Magnetic properties of the geometrically frustrated S=1/2 antiferromagnets, La2LiMoO6 and Ba2YMoO6, with the B-site ordered double perovskite structure: Evidence for a Collective Spin Singlet Ground State

Two B-site ordered double perovskites, La2LiMoO6 and Ba2YMoO6, based on the S = 1/2 ion, Mo5+, have been investigated in the context of geometric magnetic frustration. Powder neutron diffraction, heat capacity, susceptibility, muon spin relaxation(_SR), and 89Y NMR- including MAS NMR- data have been collected. La2LiMoO6 deviates strongly from simple Curie-Weiss paramagnetic behavior below 150K and zero-field cooled/ field cooled (ZFC/FC)irreversibility occurs below 20K with a weak, broad susceptibility maximum near 5K in the ZFC data. A Curie-Weiss fit shows a reduced mu_eff=1.42\mu_B, (spin only = 1.73 muB) and a Weiss temperature, \theta_c, which depends strongly on the temperature range of the fit. Powder neutron diffraction, heat capacity and 7Li NMR show no evidence for long range magnetic order to 2K. On the other hand oscillations develop below 20K in muSR indicating at least short range magnetic correlations. Susceptibility data for Ba2YMoO6 also deviate strongly from the C-W law below 150K with a similarly reduced mu_eff = 1.72\mu_B and \theta_c = - 219(1)K. Heat capacity, neutron powder diffraction and muSR data show no evidence for long range order to 2K but a very broad maximum appears in the heat capacity. The 89Y NMR paramagnetic Knight shift shows a remarkable local spin susceptibility behavior below about 70K with two components from roughly equal sample volumes, one indicating a singlet state and the other a strongly fluctuating paramagnetic state. Further evidence for a singlet state comes from the behavior of the relaxation rate, 1/T1. These results are discussed and compared with those from other isostructural S = 1/2 materials and those based on S = 3/2 and S = 1.Comment: Accepted for publication in Phys. Rev.

Cyclic nucleotide binding proteins in the <it>Arabidopsis thaliana </it>and <it>Oryza sativa </it>genomes

Abstract Background Cyclic nucleotides are ubiquitous intracellular messengers. Until recently, the roles of cyclic nucleotides in plant cells have proven difficult to uncover. With an understanding of the protein domains which can bind cyclic nucleotides (CNB and GAF domains) we scanned the completed genomes of the higher plants Arabidopsis thaliana (mustard weed) and Oryza sativa (rice) for the effectors of these signalling molecules. Results Our analysis found that several ion channels and a class of thioesterases constitute the possible cyclic nucleotide binding proteins in plants. Contrary to some reports, we found no biochemical or bioinformatic evidence for a plant cyclic nucleotide regulated protein kinase, suggesting that cyclic nucleotide functions in plants have evolved differently than in mammals. Conclusion This paper provides a molecular framework for the discussion of cyclic nucleotide function in plants, and resolves a longstanding debate about the presence of a cyclic nucleotide dependent kinase in plants.</p

Copyright and the Future of the Entertainment Industry

Panelists will discuss the intersection of copyright law and arts, entertainment, and sports law and recent legislation proposed by Congress to curb copyright infringement on the Internet. Questions posed to the panelists will include: Do copyright laws adequately protect creators in industries so heavily dominated by consumer interest? Is consumer innovation and subversion of the copyright laws forcing companies to rethink their copyright policies, as well as their business models? Is illegal activity to credit for such new developments such as the licensing regimes of Netflix and Spotify, and would it have been better to adjust copyright laws earlier in order to incentivize such moves in the market place earlier, rather than criminalizing hoards of consumers? What does the recent SOPA legislation add to this discussion? PANELISTS: Andrew Bridges is a Partner at Fenwick & West LLP, specializing in intellectual property. He has worked on some of the most influential copyright cases of the last decaded, including Grokster, Napster, Perfect 10, and RIAA v. Diamond. Michael Carrier is a Professor at Rutgers School of Law - Camden, specializing in intellectual property, innovation, antitrust, and copyright matters. He has recently published an Article with the Journal, titled An Anitrtust Framework for Climate Change. Greg Kot is a music critic for the Chicago Tribune, a host of NPR\u27s Sound Opinions, and the author of such books as Ripped: How the Wired Generation Revolutionized Music. His journalism focuses not only on music criticism but also music-related social, political and business matters. Nicole Reifman is a Partner at McDonnell Boehnen Hulbert & Berghoff LLP, specializing in intellectual property issues. Her practice focuses on patents and trademarks, including industries such as telecommunications, mechanical engineering, and medical devices. Matthew Sag is an Associate Professor of Law at Loyola University Chicago. His recent research focuses on copyright fair use issues and copyright/technology intersections and conflicts

Copyright and the Future of the Entertainment Industry

Panelists will discuss the intersection of copyright law and arts, entertainment, and sports law and recent legislation proposed by Congress to curb copyright infringement on the Internet. Questions posed to the panelists will include: Do copyright laws adequately protect creators in industries so heavily dominated by consumer interest? Is consumer innovation and subversion of the copyright laws forcing companies to rethink their copyright policies, as well as their business models? Is illegal activity to credit for such new developments such as the licensing regimes of Netflix and Spotify, and would it have been better to adjust copyright laws earlier in order to incentivize such moves in the market place earlier, rather than criminalizing hoards of consumers? What does the recent SOPA legislation add to this discussion? PANELISTS: Andrew Bridges is a Partner at Fenwick & West LLP, specializing in intellectual property. He has worked on some of the most influential copyright cases of the last decaded, including Grokster, Napster, Perfect 10, and RIAA v. Diamond. Michael Carrier is a Professor at Rutgers School of Law - Camden, specializing in intellectual property, innovation, antitrust, and copyright matters. He has recently published an Article with the Journal, titled An Anitrtust Framework for Climate Change. Greg Kot is a music critic for the Chicago Tribune, a host of NPR\u27s Sound Opinions, and the author of such books as Ripped: How the Wired Generation Revolutionized Music. His journalism focuses not only on music criticism but also music-related social, political and business matters. Nicole Reifman is a Partner at McDonnell Boehnen Hulbert & Berghoff LLP, specializing in intellectual property issues. Her practice focuses on patents and trademarks, including industries such as telecommunications, mechanical engineering, and medical devices. Matthew Sag is an Associate Professor of Law at Loyola University Chicago. His recent research focuses on copyright fair use issues and copyright/technology intersections and conflicts

Cyclic nucleotide binding proteins in the Arabidopsis thaliana and Oryza sativa genomes - Figure 3

<p><strong>Copyright information:</strong></p> <p>Taken from "Cyclic nucleotide binding proteins in the and genomes"</p> <p>BMC Bioinformatics 2005;6():6-6.</p> <p>Published online 11 Jan 2005</p> <p>PMCID:PMC545951.</p> <p>Copyright © 2005 Bridges et al; licensee BioMed Central Ltd.</p> <p>re aligned against several well studied CNB domains including regulatory subunits of PKA (RIα and RIIβ), Epac1, Epac2, and cyclic GMP dependent kinase 2 (CGK2) from humans, HCN2 from mouse and CAP. Highlighted on the alignment are glycine residues involved in loop structures (dark grey arrows), residues forming the hydrophobic pocket for cNMP binding (green arrows) and residues proposed to contact the phosphate of the cNMP (blue arrows). The highly conserved helix capping acidic residue is shown in red. Secondary structure is denoted by arrows above the alignment, with light blue for alpha helices and pink for beta sheets and is based on the secondary structure of HCN2. (B) A homology model of atCNTE1 was generated from the known structures of CNB domains. Key residues are shown as stick representations and are colored and labeled according to the color scheme described in (A). The cGMP ligand is shown in magenta and is based on the structure of cGMP bound to HCN2 [pdb: 1Q3E] superimposed over our model. Figure was generated with Molscript [83] and Raster3D [84].</p

Cyclic nucleotide binding proteins in the Arabidopsis thaliana and Oryza sativa genomes - Figure 4

<p><strong>Copyright information:</strong></p> <p>Taken from "Cyclic nucleotide binding proteins in the <em>Arabidopsis thaliana</em> and <em>Oryza sativa</em> genomes"</p> <p>BMC Bioinformatics 2005;6():6-6.</p> <p>Published online 11 Jan 2005</p> <p>PMCID:PMC545951.</p> <p>Copyright © 2005 Bridges et al; licensee BioMed Central Ltd.</p> <p><strong>Biochemical evidence for lack of a cyclic nucleotide dependent kinase in <em>Arabidopsis thaliana</em></strong>. (A) Protein kinase assays using Kemptide as a substrate. Assays were conducted on identically prepared extracts of Arabidopsis and rat adipose tissue in the presence or absence (control) of 10 μM cyclic nucleotide as indicated. Scale is offset in order to visualize both sets of results. All assays were performed in duplicate from three separate preparations and error bars indicate standard error for three separate preparations. (B) Western blotting of extracts with PKA catalytic (PKAcs) and regulatory (RII) subunit polyclonal antibodies. The PKAcs antibody was affinity purified according to [82] and used at 0.5 μg/mL while the RII antibody was used as crude serum at 5000X dilution. Lanes are as follows (A), 10 ng of purified bovine PKAcs or RII, (B) 25 μg clarified crude Arabidopsis extract, (C) 25 μg clarified crude rat adipocyte extract. Positions of mammalian PKA and RII are indicated with arrows.</p

Cyclic nucleotide binding proteins in the Arabidopsis thaliana and Oryza sativa genomes - Figure 2

<p><strong>Copyright information:</strong></p> <p>Taken from "Cyclic nucleotide binding proteins in the and genomes"</p> <p>BMC Bioinformatics 2005;6():6-6.</p> <p>Published online 11 Jan 2005</p> <p>PMCID:PMC545951.</p> <p>Copyright © 2005 Bridges et al; licensee BioMed Central Ltd.</p> <p>re aligned against several well studied CNB domains including regulatory subunits of PKA (RIα and RIIβ), Epac1, Epac2, and cyclic GMP dependent kinase 2 (CGK2) from humans, HCN2 from mouse and CAP. Highlighted on the alignment are glycine residues involved in loop structures (dark grey arrows), residues forming the hydrophobic pocket for cNMP binding (green arrows) and residues proposed to contact the phosphate of the cNMP (blue arrows). The highly conserved helix capping acidic residue is shown in red. Secondary structure is denoted by arrows above the alignment, with light blue for alpha helices and pink for beta sheets and is based on the secondary structure of HCN2. (B) A homology model of atCNTE1 was generated from the known structures of CNB domains. Key residues are shown as stick representations and are colored and labeled according to the color scheme described in (A). The cGMP ligand is shown in magenta and is based on the structure of cGMP bound to HCN2 [pdb: 1Q3E] superimposed over our model. Figure was generated with Molscript [83] and Raster3D [84].</p