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By X-ray diffraction and neutron diffraction using the isotopic substitution method, the partial structure factors /SFeFe, SFeB, and SBB well as SNN, SCC, and SNCwere determined for the metallic glass Fe80B20. The Fourier-transforms yielded the pair correlation functions Gijfrom which the atomic distances and the partial coordination numbers were calculated. The partial coordination numbers are in good agreement with those of the metastable Fe3B-phase, which is the first crystallization product formed during annealing of the metallic glass Fe80B20. The chemical short range order parameter amounts to 100%, thus indicating perfect chemical order.

Pancreatic enzyme secretion in rats has been shown to be stimulated differentially by the intestinal hormones secretin and cholecystokinin. Since it is unknown if activation of neural mechanisms have similar effects, it was the aim of the present study to examine in anesthetized rats the output of the pancreatic enzymes amylase, lipase, trypsin, and chymotrypsin before (15 min), during, and after (30 min each) vagal stimulation (5 ms, 10 V) with different frequencies (0.5, 5, 10, and 50 Hz). At 5 Hz, a maximal stimulation of all four enzymes was observed, with a peak towards the end of the vagal stimulation period. At 0.5 Hz, amylase, trypsin, and chymotrypsin were released not only in smaller quantities but also in a different time pattern (trypsin and chymotrypsin), with a maximum early during vagal stimulation. Lipase secretion remained unchanged at 0.5 Hz. At 10 Hz, the output of amylase, lipase, and trypsin was quantitatively less compared to 5 Hz. In contrast to stimulation at 0.5 and 5 Hz, the maximal enzyme output was reached after cessation of vagal stimulation (amylase and lipase). Chymotrypsin release did not change in response to vagal stimulation at 10 Hz. A frequency of 50 Hz had no influence on the secretion of any of the four enzymes determined. These data demonstrate that activation of the vagus nerves can lead to a differential release of pancreatic enzymes. The exact regulatory mechanisms of action are as yet unknown and remain to be determined.

Electron diffraction with amorphous Fe80B20and Mn73Si27yields structure factors and pair correlation functions which are discussed together with the results of X-ray- and neutron-diffraction experiments. For Mn73Si27additional interesting details are revealed. A tetrahedral model for Mn73Si27is described. Finally we show that the evaluation of partial structure factors by the three beam experiment, i.e. the combination of an electron-, X-ray- and neutron-diffraction experiment is not possible in general.

The aim of the present paper is to state differences in the spatial distribution of valency electrons for free metal atoms and for molten metals. The element lithium was chosen since both its inner and outer electrons play an important role, so that when a precise X-ray and a precise neutron-diffraction experiment have been carried out a difference, if it exists at all. should be recognizable. The correction of the X-ray data for inelastic, i.e. Compton scattering was done on the basis of an inelastic measurement performed on a spectrometer equipped with a position sensitive detector.

The binding of CC chemokines to CC chemokine receptor 5 (CCR5) triggers cellular responses that, generally, are only transient in nature. To explore the potential role of G protein-coupled receptor kinases (GRKs) in the regulation of CCR5, we performed phosphorylation experiments in a rat basophilic leukemia cell line stably expressing CCR5. The ability of various CCR5 ligands to stimulate calcium mobilization in these cells correlated with their ability to induce receptor phosphorylation, desensitization, internalization, and GRK association with the receptor. Aminooxypentane-RANTES, a potent inhibitor of human immunodeficiency virus infection, has been proposed to act through enhanced CCR5 internalization and inhibition of receptor recycling. Aminooxypentane-RANTES profoundly induced CCR5 phosphorylation, but had no effect on CCR1. In permeabilized rat basophilic leukemia CCR5 cells, monoclonal antibodies with specificity for GRK2/3 inhibited RANTES-induced receptor phosphorylation. Consistent with a role for these kinases in CCR5 regulation, 1-2 x 10(5) copies of GRK2 or GRK3 were found to be expressed in peripheral blood leukocytes. Phosphoamino acid analysis revealed that RANTES-induced CCR5 phosphorylation selectively occurs on serine residues. Our findings with receptor mutants indicate that serine residues at positions 336, 337, 342, and 349 represent GRK phosphorylation sites on CCR5. This study demonstrates that chemokines differ in their ability to induce CCR5 phosphorylation and desensitization and provides a molecular mechanism for the agonist-induced attenuation of CCR5 signaling.