Beryllium

Abstract: In order to study the coordinative behavior of doubly charged metal ions in water, a few representative metals have been chosen for theoretical studies. These are the group 2 metal ions beryllium, magnesium, and calcium and the group 12 zinc ion. The density functional method B3LYP has been used with very large basis sets. It is found that the water dipole moment and polarizabilities, which are critical for the accuracy of the binding energies, are very well reproduced provided that the basis set on the metal is included in the calculations. One of the main points of the present investigation has been to study the boundary between the first and second hydration shells. Trends of binding energies and structures are also discussed.

Abstract: Chronic beryllium disease is an occupational lung disease that begins as a cell-mediated immune response to beryllium. Although respiratory and engineering controls have significantly decreased occupational beryllium exposures over the last decade, the rate of beryllium sensitization has not declined. We hypothesized that skin exposure to beryllium particles would provide an alternative route for sensitization to this metal. We employed optical scanning laser confocal microscopy and size-selected fluorospheres to demonstrate that 0.5- and 1.0- micro m particles, in conjunction with motion, as at the wrist, penetrate the stratum corneum of human skin and reach the epidermis and, occasionally, the dermis. The cutaneous immune response to chemical sensitizers is initiated in the skin, matures in the local lymph node (LN), and releases hapten-specific T cells into the peripheral blood. Topical application of beryllium to C3H mice generated beryllium-specific sensitization that was documented by peripheral blood and LN beryllium lymphocyte proliferation tests (BeLPT) and by changes in LN T-cell activation markers, increased expression of CD44, and decreased CD62L. In a sensitization-challenge treatment paradigm, epicutaneous beryllium increased murine ear thickness following chemical challenge. These data are consistent with development of a hapten-specific, cell-mediated immune response following topical application of beryllium and suggest a mechanistic link between the persistent rate of beryllium worker sensitization and skin exposure to fine and ultrafine beryllium particles.

Abstract: § 1. It was shown by Bothe and Becker that some light elements when bombarded by α-particles of polonium emit radiations which appear to be of the γ-ray type. The element beryllium gave a particularly marked effect of this kind, and later observations by Bothe, by Mme. Curie-Joliot and by Webster showed that the radiation excited in beryllium possessed a penetrating power distinctly greater than that of any γ-radiation yet found from the radioactive elements. In Webster’s experiments the intensity of the radiation was measured both by means of the Geiger-Muller tube counter and in a high pressure ionisation chamber. He found that the beryllium radiation had an absorption coefficient in lead of about 0·22 cm.-1 as measured under his experimental conditions. Making the necessary corrections for these conditions, and using the results of Gray and Tarrant to estimate the relative contributions of scattering, photoelectric absorption, and nuclear absorption in the absorption of such penetrating radiation, Webster concluded that the radiation had a quantum energy of about 7 × 106 electron volts. Similarly he found that the radiation from boron bombarded by α-particles of polonium consisted in part of a radiation rather more penetrating than that from beryllium, and he estimated the quant um energy of this component as about 10 X 106 electron volts. These conclusions agree quite well with the supposition that the radiations arise by the capture of the α-particle into the beryllium (or boron) nucleus and the emission of the surplus energy as a quantum of radiation. The radiations showed, however, certain peculiarities, and at my request the beryllium radiation was passed into an expansion chamber and several photographs were taken. No unexpected phenomena were observed though, as will be seen later, similar experiments have now revealed some rather striking events. The failure of these early experiments was partly due to the weakness of the available source of polonium, and partly to the experimental arrangement, which, as it now appears, was not very suitable.