The role of surface properties of Thiobacillus Ferrooxidans and minerals in microbial adhesion

To explain the selective microbial adhesion of Thiobacillus ferrooxidans on pyrite, zeta potential of both the bacterium cells and the mineral was measured using the electrophoretic light scattering (ELS) technique. Simultaneously, relative hydrophobicity of the cells and the mineral was determined by the liquid-liquid partition (BATH) test and the thin-layer wicking method (TLW), respectively. Heteroaggregation of the cells with the pyrite particles has been evaluated qualitatively from the ELS spectra provided by their mixtures at different pH and interpreted in terms of the Lifshitz-van der Waals and acid-base surface thermodynamics model of microbial adhesio

Spin chirality on a two-dimensional frustrated lattice

The collective behavior of interacting magnetic moments can be strongly influenced by the topology of the underlying lattice. In geometrically frustrated spin systems, interesting chiral correlations may develop that are related to the spin arrangement on triangular plaquettes. We report a study of the spin chirality on a two-dimensional geometrically frustrated lattice. Our new chemical synthesis methods allow us to produce large single crystal samples of KFe3(OH)6(SO4)2, an ideal Kagome lattice antiferromagnet. Combined thermodynamic and neutron scattering measurements reveal that the phase transition to the ordered ground-state is unusual. At low temperatures, application of a magnetic field induces a transition between states with different non-trivial spin-textures.Comment: 7 pages, 4 figure

SpinWaves in the Frustrated Kagomé Lattice Antiferromagnet KFe\u3csub\u3e3\u3c/sub\u3e(OH)\u3csub\u3e6\u3c/sub\u3e(SO\u3csub\u3e4\u3c/sub\u3e)\u3csub\u3e2\u3c/sub\u3e

The spin wave excitations of the S = 5/2 kagomé lattice antiferromagnet KFe3(OH)6(SO4)2 have been measured using high-resolution inelastic neutron scattering. We directly observe a flat mode which corresponds to a lifted ‘‘zero energy mode,’’ verifying a fundamental prediction for the kagomé lattice. A simple Heisenberg spin Hamiltonian provides an excellent fit to our spin wave data. The antisymmetric Dzyaloshinskii-Moriya interaction is the primary source of anisotropy and explains the low-temperature magnetization and spin structure