Capillary supercritical fluid chromatography/mass spectrometry of phenolic mannich bases with dimethyl ether modified ethane as the mobile phase

The analysis of phenolic Mannich bases [Formula: see text] which are used as hardeners and accelerators for epoxy resins [Formula: see text] by capillary supercritical fluid chromatography (SFC) with dimethyl ether modified ethane as the mobile phase is described. The elution properties of several different mobile phases with respect to amines are shown. SFC with UV detection is coupled via a custom-built interface to a mass spectrometer with atmospheric pressure chemical ionization. Two technically important Mannich bases prepared by different production processes are characterized and compared with respect to their byproducts. The role of dimethyl ether during the ionization process and the fragmentation of phenolic Mannich bases is discussed.     

High Fluence Ion Irradiation of Thin Fullertte Films

Abstract

Thin fullerite films - partly covered with a thin Au layer -have been irradiated with 100 keV Arⁿ⁺ (n = 1, 6, and 12), 250 keV N⁺, and 30 keV Au⁺ ions up to high fluences, and subsequently analyzed by profilometry, Rutherford Backscattering Spectrometry (RBS), and Atomic Force Microscopy (AFM). Depending on the system, either an increase or a decrease of the film thickness after the irradiations was found, and the probing RBS α particles suffered sometimes an enhanced, and sometimes a reduced energy loss upon passage through the films. The comparison of profilometry and RBS results on uncovered and covered samples allows us to separate the different effects which influence the behavior of high-fluence irradiated fullerite samples clearly from each other. Such effects might be the incorporation of the projectile ions, density changes, phase changes, sputtering, and transport of neighbored unirradiated matter into the irradiated zone.

It is remarkable that ion irradiation of fullerite can lead as well to a densified material, with densities of about 2.1 g-cm^?3, as to a foam-like carbonaceous material with a density around 0.35 g-cm^?3 - depending on the type of projectile and its range. The latter case appears to be characteristic for high-fluence heavy noble gas implantation into fullerite. Fullerite sputtering was reconfirmed to decrease inversely with the fluence.     

Neonatal cytokines and coagulation factors in children with cerebral palsy

We explored the association of inflammatory mediators and markers of autoimmune and coagulation disorders with cerebral palsy (CP), examining 53 analytes in dried neonatal blood of 31 children with spastic CP, most born at term, and 65 control children. Ultramicroanalysis was performed by recycling immunoaffinity chromatography coupled with laser-enhanced fluorescence and chemiluminescence detection. Reactive antibodies to lupus anticoagulant, anticardiolipin, antithrombin III, and the translational product of the factor V Leiden mutation were isolated by recycling immunoaffinity chromatography and measured by capillary electrophoresis with chemiluminescence-enhanced immunoassay. Higher concentrations of interleukins (ILs) 1, 8, 9, tumor necrosis factor-alpha, and RANTES were observed in these children with CP than in any control child. There were also substantial elevations of IL-6, 11, 13, and other chemokines and colony-stimulating factors in children with CP. Antiphospholipid antibody was present in a titer of 1:100 or greater in 4 children with CP and no control child. Using cuts empirically chosen by recursive partitioning, we found higher concentrations of antibody to antithrombin III, to a translational product of factor V Leiden mutation, and to proteins C and S in children with CP than in controls. We conclude that inflammation and these coagulation abnormalities, which have interacting pathways, are important in the etiology of CP.     

Generalized Bose–Einstein Condensation Formalism and BCS Theory

Reexamining BCS theory leads one to formulate a generalized BEC formalism (GBEC) that is essentially a boson–fermion (BF) model with not two but three constituents, two bosonic being two-electron Cooper pairs (2eCPs) plus two-hole CPs (2hCPs), along with unpaired electrons. This ternary BF model contains three new ingredients: (i) CPs as real bosons in contrast to BCS pairs, which are at best so-called “hard-core bosons,” (ii) 2hCPs explicitly accounted for on an equal footing with 2eCPs, and (iii) four BF vertex interactions (analogous to electron-phonon vertices) describing the formation and dissociation of both 2eCPs and 2hCPs. The two pure gauge-invariant GBEC phases (of a total of four including the trivial normal phase) that result exhibit substantially higher T _c s than BCS theory. In addition, in contrast to the well-known BCS exponential rise of T _c from zero, the GBEC scheme exhibits the linear rise as function of doping typically observed in high-T _c superconductors.     

Extended BCS-Bose Crossover

Applying the generalized Bose-Einstein condensation (GBEC) formalism, we extend the BCS-Bose crossover theory by explicitly including hole Cooper pairs (2hCPs). From this, follows a phase diagram with two pure phases, one with 2hCPs and the other with electron Cooper pairs (2eCPs), plus a mixed phase with arbitrary proportions of 2eCPs and 2hCPs. The special-case phase when there is perfect symmetry, i.e., with ideal 50-50 proportions between 2eCPs and 2hCPs, corresponds to the usual BCS-Bose crossover. Explicitly including 2hCPs yields an extended BCS-Bose crossover which predicts improved T _c /T _F values for some conventional superconductors (i.e., with electron-phonon dynamics) when compared with experiment. To do this, we employ the BCS dimensionless coupling constant λ _{B C S} via the BCS gap equation and compare with the Bogoliubov et al. upper limit λ _{B C S} ≤ 1/2. Another phase diagram presented exhibits experimental T _c /T _F values for some conventional superconductors for arbitrary proportions between 2eCPs and 2hCPs as function of Δn = n/n _f ? 1, where n is the electron concentration and n _f that of unbound electrons at T = 0. The extended crossover is compared with experimental T _c /T _F values as well as to the gap-to- T _c ratio.