ABSTRACT
For the chemical speciation of binary compounds of tri- and tetravalent titanium, high-resolution X-ray absorption and emission spectra were recorded in different energy regimes in order to evaluate and to qualify both near-edge X-ray absorption fine structure (NEXAFS or XANES) spectroscopy and wavelength-dispersive X-ray emission spectroscopy (WDXES) as spectroscopic methods for this analytical task. A high resolving power in the excitation channel was ensured by use of monochromatic synchrotron radiation provided by BESSY II, where the soft X-ray emission spectra were recorded as well. In the hard X-ray range, emission measurements were performed at SPring-8. For a comparison of the information gained from the various methods, the titanium compounds were classified according to the bonded titanium's oxidation state. Thus, it was possible to distinguish between inner atomic effects due to different oxidation states and external effects related to the respective ligand and the surrounding structure. It becomes evident, that certain compounds, while hardly distinguishable in their Ti-K XANES spectra, still show significant differences in their emission characteristics. On the other hand, some compounds with little difference in their emission spectra are easily distinguished by their NEXAFS structures. Only the combined use of the complementary methods both in the soft and the hard X-ray range allows for a reliable speciation of tri- and tetravalent titanium compounds.
ABSTRACT
To evaluate differences in anti-tuberculous glycolipid (TBGL) antibody titers in patients who developed tuberculosis (TB) with and without gastrectomy, 11 gastrectomised patients who developed TB after surgery (GS-TB), 19 TB patients without any other complications (TB), 12 gastrectomised patients who did not develop TB after surgery (GS) and 27 healthy subjects (H) with normal findings on chest X-ray were evaluated, although there were no differences in the clinical findings at admission between the TB and GS-TB groups. The assay used here allowed us to find low anti-TBGL antibody titers in GS-TB patients.
