Resistance of Aegilops, maize and wheat genotypes to Pseudomonas syringae pathovars atrofaciens and syringae

The resistance of cereal genotypes to the artificial inoculation of Pseudomonas syringae pathovars atrofaciens (PSA) and syringae (PSS) at third leaf growth stage of development was investigated. The methods of pricking and injecting were used. The injection method produced symptoms similar to natural infection, at level of inoculum at least 107 cfu/ml. At this stage of cereal growth there was a high level of resistance to PSA and PSS. None of the Aegilops species showed the symptoms of susceptible genotypes. Only one Triticum genotype was susceptible to strains V28 and Y4895 of PSA and PSS, respectively, at the highest level of inoculum. The leaves of all Zea mays genotypes were susceptible to PSS A106 at 109 cfu/ml.Résistance des génotypes d'Aegilops, de maïs et de blé à Pseudomonas syringae pathovars (pvs) atrofaciens (PSA) et syringae (PSS). La résistance au PSA et au PSS des génotypes des céréales a été étudiée après inoculation par les méthodes de scarification et d'injection. La dernière méthode permet d'obtenir des symptômes de maladie similaires à ceux obtenus dans la nature au niveau d'inoculum de 107 cfu/ml et plus. Les plantules au stade 3 feuilles ont montré un niveau élevé de résistance à PSA et PSS. Aucune espèce d'Aegilops n'a montré d'infection comme chez les génotypes sensibles. Un seul génotype de Triticum est sensible au plus haut niveau d'inoculation par PSA V28 et PSS Y4895. Les feuilles de tous les génotypes de maïs sont sensibles au PSS A 106 à la concentration de 109 cfu/ml

Nanometer superstructure in liquid alkali-thallium alloys

Structure factors obtained from neutron diffraction measurements on liquid K-Tl and Cs-Tl alloys exhibit large prepeaks at approximately 0.77 angstrom-1 and 0.70 angstrom-1, respectively. It is concluded that the liquid contains large units of thallium atoms, possibly bearing some resemblance to those found in crystalline K8Tl11

Polyclusters and Substitution Effects in the Na–Au–Ga System: Remarkable Sodium Bonding Characteristics in Polar Intermetallics

A systematic exploration of Na- and Au-poor parts of the Na–Au–Ga system (less than 15 at. % Na or Au) uncovered several compounds with novel structural features that are unusual for the rest of the system. Four ternary compounds Na1.00(3)Au0.18Ga1.82(1) (I), NaAu2Ga4 (II), Na5Au10Ga16 (III), and NaAu4Ga2 (IV) have been synthesized and structurally characterized by single crystal X-ray diffraction: Na1.00(3)Au0.18Ga1.82(1)(I, P6/mmm, a = 15.181(2), c =9.129(2)Å, Z = 30); NaAu2Ga4 (II, Pnma, a = 16.733(3), b = 4.3330(9), c =7.358(3) Å, Z = 4); Na5Au10Ga16 (III, P63/m, a = 10.754(2), c =11.457(2) Å, Z = 2); and NaAu4Ga2 (IV, P21/c, a = 8.292(2), b = 7.361(1), c =9.220(2)Å, β = 116.15(3), Z = 4). Compound I lies between the large family of Bergman-related compounds and Na-poor Zintl-type compounds and exhibits a clathrate-like structure containing icosahedral clusters similar to those in cubic 1/1 approximants, as well as tunnels with highly disordered cation positions and fused Na-centered clusters. Structures II, III, and IV are built of polyanionic networks and clusters that generate novel tunnels in each that contain isolated, ordered Na atoms. Tight-binding electronic structure calculations using linear muffin-tin-orbital (LMTO) methods on II, III, IV and an idealized model of I show that all are metallic with evident pseudogaps at the Fermi levels. The integrated crystal orbital Hamilton populations for II–IV are typically dominated by Au–Ga, Ga–Ga, and Au–Au bonding, although Na–Au and Na–Ga contributions are also significant. Sodium’s involvement into such covalency is consistent with that recently reported in Na–Au–M (M = Ga, Ge, Sn, Zn, and Cd) phases.Reprinted (adapted) with permission from Inorg. Chem., 2013, 52 (21), pp 12502–12510. Copyright 2013 American Chemical Society.</p