Magnetism of ultrathin Cr layers and Fe/Cr multilayers studied by 119Sn probes

Cr/Sn and Fe/Cr/Sn/Cr multilayers, where monatomic Sn layers are embedded in Cr layers and Fe/Cr multilayers respectively, were prepared by means of ultrahigh-vacuum deposition technique, and the magnetic hyperfine field induced at the ¹¹⁹Sn nuclear sites was examined using conversion electron Mössbauer spectroscopy. The magnetic structures of the Cr layers are inferred from the size and direction of the magnetic hyperfine field transferred at the Sn sites.     

Multielemental Analysis of Agroindustrial By-Products Employed in Animal Feeding by INAA

Instrumental neutron activation analysis (INAA) with gamma-ray spectrometry was applied to determine As, Ca, Cd, Cl, Co, Cu, Cr, Fe, Hg, K, Mg, Mn, Mo, Na, Sb, Se and Zn in the Brazilian agroindustrial by-products. These materials are widely used in ruminant feeding. The results obtained were compared with requirement and maximum tolerable concentrations. The general conclusions from the data obtained were: (1) many by-products presented concentrations of some essential elements lower than the requirement concentrations, while in some concentrations of Cr, Fe, Mg and Se exceeded by a little the maximum tolerable concentrations, (2) the elements As, Cd, Hg and Sb, generally considered toxic, showed concentrations lower than maximum tolerable values.     

Erratum to: ”Selective separation of some ecotoxic transition metal ions from aqueous solutions using immobilized macrocyclic material containing solid phase extraction system”

The original version of the article was published in Cent. Eur. J. Chem. 9(6) (2011), pp 1019–1026. Unfortunately, the original version of this article contains mistakes in the body of Fig. 1. Here we display the corrected version of the Fig. 1.     

A palmtop-sized microfluidic cell culture system driven by a miniaturized infusion pump

A palmtop-sized microfluidic cell culture system is presented. The system consists of a microfluidic device and a miniaturized infusion pump that possesses a reservoir of culture medium, an electrical control circuit, and an internal battery. The footprint of the system was downsized to 87 × 57 mm, which is, to the best of our knowledge, the smallest integrated cell culture system. Immortalized human microvascular endothelial cells (HMEC-1) and human umbilical vein endothelial cells (HUVEC) were cultured in the system. HMEC-1 in the system proliferated at the same speed as cells in a microchannel perfused by a syringe pump and cells in a culture flask. HUVEC in the system oriented along the direction of the fluid flow. Claudin-5, a tight junction protein, was localized along the peripheries of the HUVEC. We expect that the present system is applicable to various cell types as a stand-alone and easy-to-use system for microfluidic bioanalysis.     

Co-gelation mechanism of xanthan and galactomannan

Synergistic gelation of dilute (0.1% total gums) mixed solutions of xanthan and galactomannan isolated from seeds of Delonix regia was investigated. Gelation occurred in a mixed solution of xanthan and galactomannan at 0.1% total gums at room temperature (25 °C). The flow curves of mixed solutions of native xanthan and galactomannan showed plastic behavior. The maximum elastic modulus was obtained when the ratio of the xanthan to galactomannan was 2:1 at room temperature (25 °C). The largest elastic modulus was observed in the mixture solution of deacetylated xanthan. However, a small elastic modulus was obtained in the mixture with depyruvated xanthan. The results obtained supported the interaction mechanism between xanthan and galactomannan (locust bean gum) previously proposed, and the pyruvate methyl groups might also take part in the interaction.     

Observation of a tunneling magnetoresistance effect in magnetic tunneling junctions with a high resistance ferromagnetic oxide Fe2⋅5Mn0⋅5O4 electrode

A high resistance ferromagnetic oxide Fe_2⋅5Mn_0⋅5O₄ (FMO) property as a novel spin injector was investigated with a structure of a magnetic tunneling junction (MTJ) composed of FMO/Al-O/Ni₈₀Fe₂₀, in order to reduce an impedance mismatch problem on molecular spintronics. A tunneling magnetoresistance (TMR) effect in the MTJs was observed. The maximum TMR ratio observed in the MTJs was approximately 0.85% at room temperature (RT), and the spin-polarization of FMO was estimated to be at least 0.94% at RT.     

Surface Tension of Multi-phase Flow with Multiple Junctions Governed by the Variational Principle

We explore a computational model of an incompressible fluid with a multi-phase field in three-dimensional Euclidean space. By investigating an incompressible fluid with a two-phase field geometrically, we reformulate the expression of the surface tension for the two-phase field found by Lafaurie et al. (J Comput Phys 113:134–147, 1994) as a variational problem related to an infinite dimensional Lie group, the volume-preserving diffeomorphism. The variational principle to the action integral with the surface energy reproduces their Euler equation of the two-phase field with the surface tension. Since the surface energy of multiple interfaces even with singularities is not difficult to be evaluated in general and the variational formulation works for every action integral, the new formulation enables us to extend their expression to that of a multi-phase (N-phase, N\geqslant2N\geqslant2) flow and to obtain a novel Euler equation with the surface tension of the multi-phase field. The obtained Euler equation governs the equation for motion of the multi-phase field with different surface tension coefficients without any difficulties for the singularities at multiple junctions. In other words, we unify the theory of multi-phase fields which express low dimensional interface geometry and the theory of the incompressible fluid dynamics on the infinite dimensional geometry as a variational problem. We apply the equation to the contact angle problems at triple junctions. We computed the fluid dynamics for a two-phase field with a wall numerically and show the numerical computational results that for given surface tension coefficients, the contact angles are generated by the surface tension as results of balances of the kinematic energy and the surface energy.     

Isolation and structure of koshikalide,a 14-membered macrolide from the marine cyanobacterium Lyngbya sp.

A 14-membered macrolide, koshikalide (1), was isolated from the marine cyanobacterium Lyngbya sp., and its planar structure was elucidated by spectroscopic analysis. The relative stereochemistry of C-11 and C-13 was elucidated by NOESY experiments and by an analysis of ¹H–¹H coupling constants. Koshikalide (1) exhibited weak cytotoxicity against HeLa S₃ cells.