Amino acid clusters have been studied by several groups and most notably magic number clusters and chiral recognition have been reported. In this work, we have studied the formation of amino acid clusters by electrospray ionization (ESI) and their stability by high-energy collision-induced dissociation (CID). Appearance sizes were determined for multiply charged clusters where the charge is either due to protons or to sodium ions. Finally, we conclude that chiral selectivity plays an important role in cluster formation but seems to be of minor importance for the fragmentation of mixed clusters.
Electron capture to monoanionic metal complexes in high-energy collisions with sodium vapor is shown to occur with the formation of dianions. In this way, we prepared the small dianions Cr(SCN)42-, Fe(CN)42-, Pt(NO2)22-, and Pt(C2O4)22- in the gas phase. The Cr(SCN)42- dianion Coulomb explodes into Cr(SCN)3- and SCN- with a release of kinetic energy (3.2 +/- 0.4 eV) into translational energy of the fragments. The scheme provides a way to study charge dissociation reactions of molecular dianions that are too short-lived to survive extraction from the ion source.
Fifty-eight patients with 67 fingers with flexor tendon injuries in Bunnell's "no man's land" treated with primary repair were re-examined 14-84 months after surgery. Thirty-five fingers had repair of both tendons, and in thirty-two fingers the superficialis tendon was excised and only the profundus tendon was repaired. Postoperatively thirty-one fingers were treated by Kleinert's rubber band traction, and in thirty-six fingers a dorsal plaster of Paris was applied. The functional end-result was evaluated according to the method of Buck-Gramcko. Seventy-four per cent of fingers with suture of both tendons and 47 per cent of fingers with suture of only the profundus tendon attained an excellent or good result. The fingers treated by Kleinert's rubber band traction achieved the most favourable functional result, but many inconstant factors had influence upon this evaluation. The number of re-operations were significantly higher after repair of only the profundus tendon.
Electron scattering on stored Pt(CN)2-4 and Pt(CN)2-6 centrosymmetric molecular dianions has been performed at the electrostatic storage ring ELISA. The thresholds for production of neutral particles by electron bombardment were found to be 17.2 and 18.7 eV, respectively. The relatively high thresholds reflect the strong Coulomb repulsion in the incoming channel as well as a high energetic stability of the target electrons. A trianion resonance was identified with a positive energy of 17.0 eV for the Pt(CN)2-4 square-planar complex, while three trianion resonances were identified for the Pt(CN)2-6 octahedral complex with positive energies of 15.3, 18.1, and 20.1 eV.
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