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Absorption measurements above the K edges of the low-Z atoms, C, N, O, and F, are discussed, which utilize 250-1000-eV synchrotron radiation. The paper emphasizes experimental procedures of soft x-ray absorption and extended absorption fine structure (EXAFS) measurements as well as applications and future prospects of such studies. In particular, we discuss such applications as surface EXAFS, surface absorption fine structure, and ion yield EXAFS measurements.

A technique for the single step separation of human thymus derived (T) and Bursa equivalent (B) lymphocytes was developed. Density separation of B lymphocytes and T lymphocyte-sheep red blood cell (SRBC) rosettes on Ficoll-Hypaque was modified by pretreatment of the SRBC with 2 aminoethylisothiouronium bromide hydrobromide. This modification yielded significantly purer populations of T and B cells. Up to 15 X 10(7) were separated without increasing contamination allowing for the recovery of B lymphocytes as well as T lymphocytes in sufficient numbers to use in functional assays.

Direct iodination of morphine or dihydromorphine with iodine-125 results in products that bind to antibody raised by immunization of animals with a 3-O-carboxymethylmorphine/bovine serum albumin immunogen. Iodination of morphine or dihydromorphine with iodine-127 under identical conditions failed to yield these immunologically active products, suggesting that the results obtained with iodine-125 are in part due to a radiolytic reaction not observed with the iodine-127.