Series Of Ir Research Articles

1H MR spectroscopy of the lumbar spine in diffuse osteopenia due to plasmacytoma or osteoporosis

To evaluate the role of in vivo 1H MR spectroscopic determination of relaxation times and of fat and water content to differentiate between infiltration of multiple myeloma or osteoporosis in patients with roentgenologic unclear demineralization of the lumbar spine. Ten patients each with osteoporotic reduction of bone mineral density (BMD), histologically proven multiple myeloma who showed only diffuse tumor manifestations without tumor compression fractures in the spine, and volunteers were investigated. Osteoporosis was confirmed by dual-energy X-ray absorptiometry (DXA) (Hologic QDR 2000 device, Siemens Medical Systems). The MR investigations were performed with a 1.5 T whole body system (Gyroscan S15/ACS II, Philips Medical Systems). Localized MR spectra from a cubic volume of about 8 cm3 were acquired by the PRESS technique. Chemical shift selective T1 relaxation times were obtained from an IR series, T2 was measured by variation of the interval between the first and the second echo in the volume selection scheme. Statistical analysis was done using the Kruskal-Wallis test and the Mann-Whitney test with the software SPSS. There were highly significant differences in T2 values and fat content between patients with osteoporosis and multiple myeloma. T2 values were decreased in osteoporosis (37 ms and 59 ms vs. 44 ms and 70 ms in plasmocytoma) and fat content was decreased in multiple myeloma (20% vs 31% and 34% in volunteers and osteoporosis). Between volunteers and patients with osteoporosis the differences in the T2 of the fat component was significantly different. In our preliminary experience MRS is helpful in the differential diagnosis of bony demineralization. It enables a differentiation between osteoporosis and diffuse multiple myeloma. T2 value measurements may be helpful in the diagnostic trial of osteoporosis.

Investigation of a transition metal-assisted retro Diels-Alder reaction used in the synthesis of transition metal S 2O complexes

Treatment of 4,5-diphenyl-3,6-dihydro-1,2-dithiin-1-oxide with coordinatively unsaturated transition metal complexes resulted in the production of S 2O complexes and 2,3-diphenylbutadien. A transition metal-assisted retro Diels-Alder mechanism has been proposed for this reaction. A series of IR and 1H NMR experiments and MNDO calculations on 4,5-diphenyl-3,6-dihydro-1,2-dithiin-1-oxide have been performed to gain additional information about this transformation.

Asymmetric hydrogen transfer reactions from propan-2-ol to ketones catalyzed by Ir(I) derivatives with chiral schiff bases

Alkyl phenyl ketones are effectively reduced using propan-2-ol as hydrogen source and a series of Ir(I) complexes with chiral bidentate Schiff bases as catalysts. Both the activity and the selectivity strongly depend on the nature of the substituents at the chiral center of the ligand and at the prochiral center of the substrate. Optical yields of 50% (100% conversion) are obtained in the reduction of t-butyl phenyl ketone and benzyl phenyl ketone.

Submillimeter deuterated ethyl halogen laser

The authors obtain 70 new laser submillimeter (SM) transitions on 12 isotopic modifications of ethyl halogens of the type CH/sub 3/CHDX, CH/sub 3/CH/sub 2/X, where X = C1, Br, I. The optacoustical (OA) spectra, which can be used in laser spectroscopy and isotopic analysis of these compounds with the help of a low-pressure CO/sub 2/ laser, are presented. The OA spectra were used to search for SM transitions. The preliminary identification of a series of IR and SM transitions is discussed.