Authors:R. Brodzinski, J. Langford, M. Thomas, and O. Harling
Procedures are described for rapid, high yield chemical separation of niobium and vanadium from surfaces of quartz, silicon,
and carbon following thermal neutron activation. Practical detection limits for stable niobium and vanadium are 7·1010 and 6·1011 atoms respectively. Application of these procedures to controlled thermonuclear reactor materials studies is discussed.
Authors:S. Marsaud, J. Thomas, M. Fallavier, J. Mackowski, and J. Tousset
Alpha particles backscattering has been used in order to study the thermal diffusion of gold electrodes into thin films of
chalcogenide glasses. The performances of the method allowing approximately a 2000 Å analyzing depth (below the front electrode
or near the surface when only back electrode is concerned) diffusion profiles are obtained. If the gold diffusion into As
can be considered as classical, following the Fick's law and showing a rather low activation energy (0.6 eV), the diffusion
into AsTe is quite different. A flat and deep gold profile develops through the entire thickness of the film (still below
the glass transition temperature). A tentative interpretation is proposed, based upon a “preferential path” diffusion, introducing
a new diffusion coefficient aside the bulk one. Several significant features support this interpretation and suggest further
investigations. Nevertheless we have already a good understanding of the electrical degradation of such devices trough, the
correlation with the diffusion process.
Authors:R. White, P. Thomas, M. Philips, R. Wuhrer, and J. Guerbois
The deleterious interaction
of some traditional sulphide artists pigments and copper ions results in the
formation of black copper sulphides, in particular, covellite (CuS), and,
hence, the discolouration of valuable artworks. In this paper the interaction
of malachite, a source of copper(II) ions, with the pigment cadmium yellow,
a sulphide pigment comprising of a solid solution of cadmium and zinc sulphides,
is investigated by XRD and TG-MS. XRD showed the presence of the copper sulphide
and cadmium carbonate phases, produced by a simple ion exchange mechanism.
TG-MS showed the complexity of the range of metastable phases produced. The
identification of these phases, however, requires further work.
Authors:E. Fiani, L. Perier-Camby, G. Thomas, and M. Sanalan
Adsorption isotherms of n-butane on a granulated activated carbon were measured by two different but complementary experimental
methods: calorimetry and gravimetry. Adsorption heats were determined in different ways. For the system studied, the experimental
results prove that the adsorbent offers a homogeneous site distribution. Besides, there can be differences between the adsorption
heat values which might come from the way they are obtained (by calculation or direct measurements).
Authors:O. Farmer, K. Olsen, M. Thomas, and S. Garofoli
A method for the separation and determination of total and isotopic uranium and plutonium by ICP/MS was developed for IAEA
samples on cellulose-based media. Preparation of the IAEA samples involved a series of redox chemistries and separations using
TRU® resin (Eichrom). The sample introduction system, an APEX nebulizer (Elemental Scientific, Inc.), provided enhanced nebulization
for a several-fold increase in sensitivity and reduction in background. Application of mass bias (ALPHA) correction factors
greatly improved the precision of the data. By combining the enhancements of chemical separation, instrumentation and data
processing, detection levels for uranium and plutonium approached high attogram levels.
Authors:Thomas V. Pollet, Toon Kuppens, and Robin I. M. Dunbar
As suggested by previous research, childlessness can thoroughly affect
the likelihood of giving and receiving help to kin, even in modern societies.
In this paper we show that childless women over thirty-five have had more recent
contact with their nephews/nieces than mothers. Yet, both groups showed no
significant differences in contact with their uncles/aunts. This suggests
heightened social investment in kin with high reproductive value by childless
women compared to mothers. Results are discussed with reference to kin
Authors:J. Laul, M. Smith, C. Thomas, P. Jackson, and N. Hubbard
Analytical procedures for measuring various radionuclides in the238U and232Th chains in briney waters are described. Using methods such as mass spectrometry, and alpha, beta and gamma spectrometry, the desired measurement sensitivity required for each of the radionuclides is achieved.233U,228Th,208Po,212Pb, and133Ba are used as tracers for chemical yield recoveries. Typical precision of the results range from 5–20%.
Authors:C. Mazzocchia, R. Anouchinsky, A. Kaddouri, M. Sautel, and G. Thomas
NiMoO4 obtained by calcination of precursors has been shown to be a very effective catalyst for oxidative dehydrogenation of propane
into propene. Preparation conditions and thermal decomposition of two precursors have been studied by TG-DTA, HTXRD, FFT-IR,
and thermo-desorption coupled to mass spectroscopy in order to determine their composition and to define the best treatment
to favour the oxidative dehydrogenation process. The selectivity and activity for propane transformation into propene are
very different depending on the nature of the precursor and of the active phases obtained after thermal activation. The more
selective high-temperature β phase of NiMoO4 has been obtained at a lower temperature (500°C) than previously reported (700°C).
Authors:Greta Gölz, Thomas Alter, Stefan Bereswill, and Markus M. Heimesaat
We have previously shown that Arcobacter butzleri infection induces Toll-like receptor (TLR) -4 dependent immune responses in perorally infected gnotobiotic IL-10−/− mice. Here, we analyzed TLR-4-dependent expression of genes encoding inflammatory mediators and matrix-degrading gelatinases MMP-2 and -9 in the small and large intestines of gnotobiotic TLR-4-deficient IL-10−/− mice that were perorally infected with A. butzleri strains CCUG 30485 or C1, of human and chicken origin, respectively. At day 6 following A. butzleri infection, colonic mucin-2 mRNA, as integral part of the intestinal mucus layer, was downregulated in the colon, but not ileum, of IL-10−/− but not TLR-4−/− IL-10−/− mice. CCUG 30485 strain-infected TLR-4-deficient IL-10−/− mice displayed less distinctly upregulated IFN-γ, IL-17A, and IL-1β mRNA levels in ileum and colon, which was also true for colonic IL-22. These changes were accompanied by upregulated colonic MMP-2 and ileal MMP-9 mRNA exclusively in IL-10−/− mice. In conclusion, TLR-4 is essentially involved in A. butzleri mediated modulation of gene expression in the intestines of gnotobiotic IL-10−/− mice.