Fluctuation effects in the phase separation of solid3He-4He mixtures

We analyze the excess specific heat above the phase-separation temperature in solid mixtures of³He and⁴He as due to the fluctuations that represent the symmetry of the condensing state. In a³He-rich solid, the fluctuations of the⁴He-rich phase are two-dimensional, while in an even mixture they are three-dimensional. The density fluctuations are characterized by a length scale that is essentially the interparticle spacing.     

The evolution of polyacetylene morphology upon doping

Knowledge of the evolution of the fibrillar morphology of polyacetylene with doping is critical for an understanding of the chemistry of the doping process, the mechanisms for charge transport in the polymer and the insulator-metal transition. Earlier scanning electron microscopic (SEM) studies reported conflicting results of either swelling of the fibrils or a gross morphological change. In order to resolve these differences, SEM experiments were carried out to compare the changes in apparent morphology due to the use of various coatings and coating methods used to reduce charging effects, the effects of tearing on the cross sectional morphology and the effects of contrast in imaging the samples. Results definitively show that the fibrillar morphology is retained upon doping.     

Crystallographic study of BaTiO3-BaM1/3N2/3O3 solid solutions (M=Co or Mg and N=Nb or Ta)

In order to understand the effect of niobium, tantalum, cobalt and magnesium cations on the ferroelectric properties of barium titanate we study solid solutions between BaTiO₃ and BaM_1/3N_2/3O₃ perovskite compounds where M=Co²⁺ or Mg²⁺ and N=Nb⁵⁺ or Ta⁵⁺. These solid solutions become cubic at room temperature for very weak additions. This result cannot be explained by geometrical consideration and suggests that an intermediate solid solution is made for weak additions.     

Lipids and stroke: a paradox resolved

The usual methods like hypotension, isovolaemic haemodilution, autologous transfusion and peri-operative blood salvage may significantly reduce the need for homologous blood transfusion in haemorrhagic surgery and also the risk of transmitting infectious agents. Erythropoietin (EPO) is now available and is used to stimulate red cell regeneration in pre-operative autologous blood donation. In acute anaemia, many studies have shown that the stimulation of endogenous erythropoietin production could be very high and accelerate red blood cell production. Taking higher quantities of blood than usual induces a secretion of endogenous erythropoietin, and could be an alternative for the utilization of exogenous EPO in autologous blood donation.     

Vibrational properties of Li-doped polyacetylene

Raman experiments on (CH)_x chemically doped with Li are reported. A very fast cis-trans isomerization is observed upon doping. Raman spectra of Li-doped cis or trans films show special features characteristic of short trans segments which remain undoped. Further, an additional Raman band at $\text{≌ 1570}\text{cm}{}^{\mathrm{?1}}$ is reported, as in the p-type doping case, associated with doped parts of the polymer. A possible interpretation with intercalated domains is suggested.     

A New Method to Increase the Margin of Multilayer Perceptrons

A new method to maximize the margin of MLP classifier in classification problems is described. Thismethod is based on a new cost function which minimizes the variance ofthe mean squared error. We show that with this cost function the generalizationperformance increase. This method is tested and compared with the standard mean square errorand is applied to a face detection problem.     

Uncertainty analysis of EQeau,a remote sensing based model for snow water equivalent estimation

This paper is dedicated to the application of uncertainty analysis on the EQeau model. EQeau is a semi‐empirical model that uses satellite C‐band SAR data to estimate Snow Water Equivalent. The uncertainty issues of this model's application have not yet been addressed. The uncertainty analysis permits the evaluation of the impact of input data and model parameters on the model outputs and the assessment of the implications and limitations of the model's application.     

Characterization of a multiple ligand-gated ion channel cellular membrane affinity chromatography column and identification of endogenously expressed receptors in astrocytoma cell lines

Cellular membranes obtained from the 1321N1 and A172 astrocytoma cell lines were immobilized on a chromatographic phase to create cellular membrane affinity chromatography (CMAC) columns, CMAC(1321N1) and CMAC(A172). The columns were characterized using frontal affinity chromatography with [(3)H]-epibatidine as the marker ligand and epibatidine, nicotine, and methyllycaconitine as the displacers. The results indicated that the columns contained homomeric alpha7 nicotinic acetylcholine receptors (alpha7 nAChR) and heteromeric nicotinic acetylcholine receptors (alpha(x)beta(y) nAChRs), which was confirmed by the addition of subtype-specific inhibitors, alpha-bungarotoxin (alpha7 nAChR) and kappa-bungarotoxin (alpha(x)beta(y) nAChR) to the mobile phase. The presence of two additional ligand-gated ion channels (LGICs), gamma-aminobutyric acid (GABA(A)) and N-methyl-D-aspartic acid (NMDA), was established using frontal affinity chromatography with flunitrazepam and diazepam (GABA(A) receptor) and MK-801 and NMDA (NMDA receptor). The presence of the four LGICs was confirmed using confocal microscopy and flow cytometry. The results indicate that the CMAC(1321N1) and CMAC(A172) columns contain four independently functioning LGICs, that the columns can be used to characterize binding affinities of small molecules to each of the receptors, and that the CMAC approach can be used to probe the expression of endogenous membrane receptors.