Study of arsenic reabsorption in the body by the neutron activation analysis after thermal springs treatments

At French spa, La Bourboule, arsenical mineral waters are applicated by several ways. The process and degree of absorption of water are not well known; so, we tried to study absorption, measuring arsenic concentration in the blood and in some organs. On rabbits, thirty minutes after the animal had drunk mineral water, the increase of arsenic concentration in its blood is about twenty times and it is only about three to nine time in lungs, bronchia and traches. On human subjects, it was observed an increase of five times in the blood, two hours after treatment.     

Rupture energy and wetting behavior of pendular liquid bridges in relation to the spherical agglomeration process

A novel micro force balance (MFB) is used to investigate the rupture energy of a silicon oil liquid bridge formed in water between two glass particles of either the same or dissimilar surface energy. Rupture energies are integrated from force curves and compared with the models proposed by Simons et al. (Chem. Eng. Sci. 49 (1994) 2331) and Pitois et al. (Eur. Phys. J. B 23 (2001) 79). The latter showed slightly better agreement to the experimental data. Glass ballotini ( approximately 100 microm diameter) are either silanized, in order to increase their wettability toward the oil binder, or kept untreated. Results showed how the interaction between the binder and the particle influences the geometry, the capillary pressure, the force, and the rupture energy of the liquid bridge. Higher values of force and liquid bridge energy were measured between particles characterized by higher interaction (silanized-silanized configuration). A thermodynamic approach to the evaluation of the energy stored in a liquid bridge is also proposed. The mechanical work done to stretch apart the liquid bridge is evaluated as the difference of internal and hysteresis energy between the initial and the rupture configuration of the bridge. This approach showed good agreement with the experimental data only for liquid bridges formed between silanized and untreated glass particles.     

Extraction and characterisation of anti-oestradiol immunoglobulins from human serum by high-performance liquid chromatography

Summary Immunoglobulins have been extracted from human and rabbit serum by size exclusion high performance liquid chromatography. In the case of rabbit immunized against ethinyl-oestradiol and woman having arterial thrombosis in the course of oral contraceptive use, the extracted immunoglobulins present a very high affinity for 17 -oestradiol sulphate. The measurement of affinity to this compound of different extracted immunoglobulins allows a quantitative determination of these specific proteins. Comparative studies with radioimmunoassays are in good agreement.Presented at the 14th International Symposium on Chromatography London, September, 1982     

Re-sourcing teachers’ work and interactions: a collective perspective on resources, their use and transformation

This paper reviews the literature on the theme of mathematics teachers’ work and interactions with resources, taking a particular perspective, the so-called ‘collective perspective’ on resources, their use and transformation. The review is presented under three headings: (1) theoretical frameworks commonly used in this area of research; (2) teachers’ interactions with resources in terms of their design and use; and (3) teachers’ interactions with resources in terms of teacher learning and professional development. From the literature, and the collection of papers in this issue, we argue that the collective dimensions play an important role in mathematics teachers’ work with resources and in their professional learning/development. Further empirical investigations are likely to be needed on: how teachers may work in collectives and with resources, and in which ways ‘productive’ collectives may form and work together; which roles particular resources can play in these delicate constellations and how particular resources may support teachers in their work and learning; and which kinds of resources offer opportunities for community building.     

Obscurine: a new cyclostachine acid derivative from Beilschmiedia obscura

From the methylene chloride extract of the stem bark of Beilschmiedia obscura, a new cyclostachine derivative, obscurine (1), has been isolated, together with six known compounds. The structure of compound 1 was established by spectroscopic methods, including 1- and 2-dimensional NMR techniques.     

Absolute measurements of intensities, positions and self-broadening coefficients of R branch transitions in the ν2 band of ammonia

A complete spectroscopic study of 22 ammonia transitions belonging to the ν₂ fundamental band has been undertaken using a high-resolution Fourier transform spectrometer. More than 80 spectra of pure ammonia were recorded at different conditions of temperature (235, 264, and 296 K) and pressure (160-2000 Pa). Special attention was paid to the determination of the absolute wavenumber scale and of the ammonia partial pressure, which allowed to determine absolute positions (8×10⁻⁵ cm⁻¹), absolute intensities (<2%) and self-broadening coefficients (<2%) with high accuracy. Measured intensities show a mean difference of more than 13% compared to intensities extracted from the HITRAN (2008) database while absolute positions are in very good agreement (−3.3×10⁻⁵ cm⁻¹) with database values. Self-pressure shift coefficients are also reported.     

Electron Transfer Dissociation of Photolabeled Peptides. Backbone Cleavages Compete with Diazirine Ring Rearrangements

Gas-phase conformations and electron transfer dissociations of pentapeptide ions containing the photo-Leu residue (L*) were studied. Exhaustive conformational search including molecular dynamics force-field, semi-empirical, ab initio, and density functional theory calculations established that the photo-Leu residue did not alter the gas-phase conformations of (GL*GGK? + ?2H)²⁺ and (GL*GGK-NH₂?+?H)⁺ ions, which showed the same conformer energy ranking as the unmodified Leu-containing ions. This finding is significant in that it simplifies conformational analysis of photo-labeled peptide ions. Electron transfer dissociation mass spectra of (GL*GGK? + ?2H)²⁺, (GL*GGK-NH₂?+?2H)²⁺,(GL*GGKK?+?2H)²⁺, (GL*GLK?+?2H)²⁺, and (GL*LGK?+?2H)²⁺ showed 16 %–21 % fragment ions originating by radical rearrangements and cleavages in the diazirine ring. These side-chain dissociations resulted in eliminations of N₂H₃, N₂H₄, [N₂H₅], and [NH₄O] neutral fragments and were particularly abundant in long-lived charge-reduced cation-radicals. Deuterium labeling established that the neutral hydrazine molecules mainly contained two exchangeable and two nonexchangeable hydrogen atoms from the peptide and underwent further H/D exchange in an ion–molecule complex. Electron structure calculations on the charge-reduced ions indicated that the unpaired electron was delocalized between the diazirine and amide π* electronic systems in the low electronic states of the cation-radicals. The diazirine moiety in GL*GGK-NH₂was calculated to have an intrinsic electron affinity of 1.5 eV, which was further increased by the Coulomb effect of the peptide positive charge. Mechanisms are proposed for the unusual elimination of hydrazine from the photo-labeled peptide ions.