Temperature dependence of the electronic structure of Sr14Cu24O41 studied by resonant inelastic X-ray scattering

We report a resonant inelastic X-ray scattering (RIXS) study of charge excitations in the two-leg ladder Sr₁₄Cu₂₄O₄₁. RIXS spectra at 1–5 eV are found to be dependent on temperature. An intraband excitation of the ladder, which appears as a continuum intensity below the Mott gap, decreases in intensity with temperature. Because the intraband excitation is related to the dynamics of doped holes in the ladder, its decrease of the intraband excitation is attributed to the reduction of the mobile holes in the ladder at low temperature.     

(e, 3e) Differential cross section of He (21 S) and He (23 S)

The angular distribution of the five-fold differential cross section for the electron impact double ionization of He (2¹ S) and He (2³ S) has been studied. The kinematical conditions for maxima/minima in the angular distribution for the two cases have been compared. The two-step process for the double ionization is found to contribute very little in the triplet case.     

Synthesis of platinum complexes of 2-aminomethylpyrrolidine derivatives for use as carrier ligands and their antitumor activities

In order to study a new antitumor platinum complex, various platinum complexes were prepared from 2-amino-methylpyrrolidine derivatives synthesized to serve as carrier ligands and tested for their antitumor activity against Colon 26 carcinoma (s.c.-i.p. system) and P388 leukemia (i.p.-i.p. system) in mice. 2-Aminomethylpyrrolidine proved to be the most effective carrier ligand in its amine derivatives. The structure-activity relationships of the carrier ligands in the platinum complexes with dichloro, oxalato, 1,1-cyclobutanedicarboxylato and dichlorodihydroxo as leaving group were clearly shown on the Colon 26 carcinoma screen and were as follows: the antitumor activity of the platinum complexes with any leaving groups was considerably decreased by the substitution of hydrogen by alkyl group (Me, Et) on nitrogen of aminomethyl and the effects of 1,1-cyclobutanedicarboxylato Pt(II) complexes completely disappeared with the same substitution on nitrogen of pyrrolidine. In all the tested platinum complexes 2-aminomethylpyrrolidine(1,1-cyclobutanedicarboxylato)platin um(II) (15) exhibited the most potent antitumor activity. 15 was superior to 1,1-cyclobutanedicarboxylatodiammineplatinum(II) (CBDCA) and similar to cis-diamminedichloroplatinum(II) (CDDP) on the Colon 26 carcinoma screen but it was inferior to CBDCA and CDDP on the P388 leukemia screen. Furthermore, 15 showed more potent antitumor activity than CBDCA against Colon 38 carcinoma (s.c.-i.p. system).     

High-performance liquid chromatographic determination of pamaquine, primaquine and carboxy primaquine in calf plasma using electrochemical detection.

A high-performance liquid chromatographic method with electrochemical detection is described for quantification of pamaquine, primaquine and carboxy primaquine in calf plasma. After the proteins had been precipitated with acetonitrile, the drugs were separated on a 5-microns C18-modified polymer gel column with an isocratic mobile phase. The detection limit was 0.01 microgram/ml in plasma for all three compounds. The applicability of the method in pharmacokinetic studies was demonstrated by determining the plasma concentrations of the three substances in calves administered a single dose of pamaquine or primaquine.     

Equilibria and kinetics of the extraction of gallium with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone

The equilibria and kinetics of the solvent extraction of gallium(III) from aqueous monochloroacetic acid [HA] media with a benzene solution of 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone [PMBP or HL] has been studied at 25 ± 0.1° and an ionic strength of 0.2. The species extracted was found to be GaL₃. The value of the acid dissociation constant of PMBP determined spectrophotometrically was 1.17 × 10⁻⁴. The values of the partition coefficient of PMBP and the extraction constant of its gallium complex between an aqueous and a benzene phase were found to be 3.72 × 10³ and 2.51 × 10⁴, respectively. The rate of extraction was first-order with respect to the concentrations of gallium(III) in the aqueous phase and PMBP in the organic phase, inversely first- and second-order with respect to the hydrogen-ion concentration and zero- and first-order with respect to the concentration of monochloroacetate ions. Two mechanisms operate for this extraction, depending on the pH of the aqueous phase, one where the formation of the first complex, GaL²⁺, between Ga³⁺ and L⁻ in the region of pH < 1.6 becomes the rate-determining step, and the other where the formation of the first complex between GaA²⁺ and L⁻ in the region of pH 2.0–2.3 is the rate-determining step. The rate constant for the first of these reactions was calculated to be 1.62 × 10⁴l.mole⁻¹.sec⁻¹, but that for the second could not be determined.