Ice chromatography: current progress and future developments

Ice chromatography, in which water-ice particles are employed as a chromatographic stationary phase, has proven an efficient technique for probing the solution/ice interface. The preparation of fine ice particles has allowed us to not only obtain higher-resolution separation but also investigate the molecular processes occurring on the ice surface in more detail. Chromatographic investigations have revealed that two or more hydrogen bonds are simultaneously formed between a solute and the dangling bonds on the ice surface when the solute gives measurable retention. Several compounds, including estrogens, amino acids, and acyclic polyethers, have been successfully separated by ice chromatography with a hexane-based mobile phase. In addition, this method effectively probes the surface melting of the ice stationary phase and the liquid phase that coexists with water ice at thermodynamic equilibrium. The thickness of the surface liquid layer and the size of the liquid phase that grows inside an ice particle have been evaluated. The perspectives of this method are also discussed.      

Steady State Thermodynamics

The present paper reports our attempt to search for a new universal framework in nonequilibrium physics. We propose a thermodynamic formalism that is expected to apply to a large class of nonequilibrium steady states including a heat conducting fluid, a sheared fluid, and an electrically conducting fluid. We call our theory steady state thermodynamics (SST) after Oono and Paniconi's original proposal. The construction of SST is based on a careful examination of how the basic notions in thermodynamics should be modified in nonequilibrium steady states. We define all thermodynamic quantities through operational procedures which can be (in principle) realized experimentally. Based on SST thus constructed, we make some nontrivial predictions, including an extension of Einstein's formula on density fluctuation, an extension of the minimum work principle, the existence of a new osmotic pressure of a purely nonequilibrium origin, and a shift of coexistence temperature. All these predictions may be checked experimentally to test SST for its quantitative validity.     

Conversion ratio to F-H center pairs from self-trapped excitons in alkali chloride crystals

Abstract

The time delayed double excitation spectroscopy has been utilized to determine the conversion ratio to F-H center pairs from self-trapped excitons(STE_L) at the lowest state (1s[sgrave]_g;a_1g). The final conversion ratios, η_F/(η_F+η_X), were 0.86, 0.49 and 0.20 for NaCl, KCl and RbCl at 14K, respectively. The conversion efficiency (η =η_F+η_X) from STE_L to F-H center pairs(η_F) and to unknown states(η_X) were 0.25, 0.90 and 0.76 for the hole excitation to π_g, while 0.03, 0.01 and 0.01 for the electron excitation to b_1u, b_2u or b_3u, in NaCl, KCl and RbCl, respectively.     

Solid phase extraction of zinc(II) using a PVC-based polymer inclusion membrane with di(2-ethylhexyl)phosphoric acid (D2EHPA) as the carrier

A polymer inclusion membrane (PIM) is reported consisting of 45% (m/m) di(2-ethylhexyl)phosphoric acid (D2EHPA) immobilized in poly(vinyl chloride) (PVC) for use as a solid phase absorbent for selectively extracting Zn(II) from aqueous solutions in the presence of Cd(II), Co(II), Cu(II), Ni(II) and Fe(II). Interference from Fe(III) in the sample is eliminated by precipitation with orthophosphate prior to the extraction of Zn(II). Studies using a dual compartment transport cell have shown that the Zn(II) flux (2.58 × 10⁻⁶ mol m⁻² s⁻¹) is comparable to that observed for supported liquid membranes. The stoichiometry of the extracted complex is shown to be ZnR₂·HR, where R is the D2EHPA anion.     

Steady-state thermodynamics for heat conduction: microscopic derivation

Starting from microscopic mechanics, we derive thermodynamic relations for heat conducting nonequilibrium steady states. The extended Clausius relation enables one to experimentally determine nonequilibrium entropy to the second order in the heat current. The associated Shannon-like microscopic expression of the entropy is suggestive. When the heat current is fixed, the extended Gibbs relation provides a unified treatment of thermodynamic forces in the linear nonequilibrium regime.     

Inhibitory effect of cis-dehydromatricaria ester isolated from Solidago altissima on the growth of mammalian cells

A cell growth inhibitory substance was isolated from Solidago altissima, which is known as a naturalized weed. The data of infrared spectrum, proton and carbon-13 nuclear magnetic resonance spectrum, and mass spectrum were identical with those of cis-dehydromatricaria ester. The compound inhibited both tumor and normal mammalian cells.     

Implantation of a glass capillary-based enzyme electrode in mouse hippocampal slices for monitoring of <Emphasis Type="SmallCaps">L</Emphasis>-glutamate release

A glass capillary-based enzyme electrode (tip size ≈10 μm) was implanted in the target neuronal region, i.e., dentate gyrus (DG) or cornu ammonis 1 (CA1), of acute brain slices at a depth of ≈10 μm from the slice surface in order to allow the monitoring of chemical stimulant-induced changes in L-glutamate levels. First, the sampling behavior of a glass capillary in a slice was investigated by visualizing the transport of a fluorescence dye. Then, the electrode was applied to real-time monitoring of L-glutamate release in acute hippocampal slices stimulated by surface application of a stimulant solution. The extracellular application of KCl (0.10 M) increased the glutamate levels in the DG and CA1 regions, respectively. The enhancement of L-glutamate concentration at DG was much larger than at CA1. The application of tetraethylammonium chloride (TEA) (25 mM) enhanced the L-glutamate level in the DG region and the enhanced level did not return to the initial value before TEA application even when washed with an artificial cerebrospinal fluid (ACSF). The usefulness of a surface-implanted capillary electrode for monitoring L-glutamate release in acute brain slices is discussed.     

Thermodynamic behavior of an area-preserving multibaker map with energy

A multibaker map with “kinetic energy” is proposed which incorporates an external field. The map is volume-preserving, time-reversal symmetric and conserves total energy. In an appropriate macroscopic limit, the particle distribution is shown to obey a Smoluchowski-type equation. For the cases without any external field and with a constant external force, the nonequilibrium stationary states are constructed by solving the evolution equation of the partially integrated distribution functions. These states are described by singular functions such as incomplete Takagi functions and Lebesgue's singular functions. In an appropriate macroscopic limit, the mass flows for the stationary states are shown to be identical to the ones expected from the Smoluchowski equation and a “heat flow” proportional to the local energy gradient appears. The Gaspard–Gilbert–Dorfman entropy production is calculated for the stationary states and is shown to be positive. Particularly, for the case with a constant external force, when the energy distribution is independent of the spatial distribution, the entropy production reduces to the one consistent with classical thermodynamics. The result shows that there exists a volume-preserving driven multibaker map whose entropy production is consistent with classical thermodynamics. Received: 17 August 1998 / Accepted: 17 September 1998 / Published online: 15 February 1999     

Spontaneous Symmetry Breaking in Coupled Bose–Einstein Condensates

Journal of Statistical Physics - We study a system of two hardcore bosonic Hubbard models weakly coupled with each other by tunneling. Assuming that the single uncoupled model exhibits off-diagonal...