Spin-transfer mechanism of ferromagnetism in polymerized fullerenes: AbinitioAb initio calculations

A mechanism of the high temperature ferromagnetism in polymerized fullerenes is suggested. It is assumed that some of the C$_{60}$ molecules in the crystal become magnetically active due to spin and charge transfer from the paramagnetic impurities (atoms or groups), such as hydrogen, fluorine, hydroxyl group OH, amino group NH$_2$, or methyl group CH$_3$, dispersed in the fullerene matrix. The exchange interaction between the spins localized on the magnetically active fullerenes is evaluated using \textit{ab initio} calculations. The nearest neighbour and next nearest neighbour exchange interaction is found to be in the range $0.1\div 0.3$ eV, that is, high enough to account for the room temperature ferromagnetism.Comment: typos corrected, 8 pages, 3 figures, LaTe

Synthesis and properties of interaction product of rosin and diethylenetriamine

Amides of rosin resin acids are a promising material for use in the technology of paper and cardboard in order to increase its strength characteristics. Therefore product of rosin resin acids interaction with diethylenetriamine arouses interest. The influence of temperature and duration of the process of interaction of rosin resin acids with diethylenetriamine on the acid number of the product are examined in this article. Melting point of the received rosin amides was defined. The thermal stability of the reaction product of abietic acid with diethylenetriamine was studied. It was proved that this product contains the appropriate functional groups using IRspectroscopy

Fingerprints of Spin-Orbital Physics in Crystalline O2_2

The alkali hyperoxide KO$_2$ is a molecular analog of strongly-correlated systems, comprising of orbitally degenerate magnetic O$_2^-$ ions. Using first-principles electronic structure calculations, we set up an effective spin-orbital model for the low-energy \textit{molecular} orbitals and argue that many anomalous properties of KO$_2$ replicate the status of its orbital system in various temperature regimes.Comment: 4 pages, 2 figures, 1 tabl

A four-subunit DNA polymerase ζ complex containing Pol δ accessory subunits is essential for PCNA-mediated mutagenesis

DNA polymerase ζ (Pol ζ) plays a key role in DNA translesion synthesis (TLS) and mutagenesis in eukaryotes. Previously, a two-subunit Rev3–Rev7 complex had been identified as the minimal assembly required for catalytic activity in vitro. Herein, we show that Saccharomyces cerevisiae Pol ζ binds to the Pol31 and Pol32 subunits of Pol δ, forming a four-subunit Pol ζ(4) complex (Rev3–Rev7–Pol31–Pol32). A [4Fe-4S] cluster in Rev3 is essential for the formation of Pol ζ(4) and damage-induced mutagenesis. Pol32 is indispensible for complex formation, providing an explanation for the long-standing observation that pol32Δ strains are defective for mutagenesis. The Pol31 and Pol32 subunits are also required for proliferating cell nuclear antigen (PCNA)-dependent TLS by Pol ζ as Pol ζ(2) lacks functional interactions with PCNA. Mutation of the C-terminal PCNA-interaction motif in Pol32 attenuates PCNA-dependent TLS in vitro and mutagenesis in vivo. Furthermore, a mutant form of PCNA, encoded by the mutagenesis-defective pol30-113 mutant, fails to stimulate Pol ζ(4) activity, providing an explanation for the observed mutagenesis phenotype. A stable Pol ζ(4) complex can be identified in all phases of the cell cycle suggesting that this complex is not regulated at the level of protein interactions between Rev3-Rev7 and Pol31-Pol32

Observation of Magnetic Edge State and Dangling Bond State on Nanographene in Activated Carbon Fibers

The electronic structure of nanographene in pristine and fluorinated activated carbon fibers (ACFs) have been investigated with near-edge x-ray absorption fine structure (NEXAFS) and compared with magnetic properties we reported on previously. In pristine ACFs in which magnetic properties are governed by non-bonding edge states of the \pi-electron, a pre-peak assigned to the edge state was observed below the conduction electron {\pi}* peak close to the Fermi level in NEXAFS. Via the fluorination of the ACFs, an extra peak, which was assigned to the \sigma-dangling bond state, was observed between the pre-peak of the edge state and the {\pi}* peak in the NEXAFS profile. The intensities of the extra peak correlate closely with the spin concentration created upon fluorination. The combination of the NEXAFS and magnetic measurement results confirms the coexistence of the magnetic edge states of \pi-electrons and dangling bond states of \sigma-electrons on fluorinated nanographene sheets.Comment: 4 figures, to appear in Phys. Rev.

Application features of hexane diacid polycondensation products with diethylene triamine and resin acids in paper technology

Article examines the effectiveness of the reinforcing action for the first time received additives based on adipic acid with diethylenetriamine and tall oil rosin acids rosin. It was found that the synthesized polymers exhibit polyaminoamide hydrophobic properties due to the presence in their structure of resin acids . Strengthening effect of these compoundsis shown by introducing the structure of nitrogencontaining groups contribute to the formation of additional interfiber bonds. Tests have paper samples containing in their composition nitrogen compounds showed that hardening effect new synthesized polymers are not inferior to imported compound Melapret PAE / A, and hydrophobicity and the wet paper samples with the newly synthesized polymers exceed the value of these indicators for the paper samples containing imported analog

New polymers synthesis based on resin acids amides for waste paper hardening

Strengthening effect on the kinds of junk paper provides nitrogen poly-measures based on amides of resin acids. Conditions developed modification of resin acids and polycondensation of adipic acid with a polyamine allow to obtain a polymer with an acid number of 20–30 mg KOH/g and infinitely miscible with water. The resulting polymer of the physico-chemical properties and hardening effect is not inferior to the best imported counterpart Melapret PAE/A