RESUMEN
The charge density (CD) of coordination polymer Co3(C8H4O4)4(C4H12N)2(C5H11NO)3 (1) has been determined from multipole modeling of structure factors obtained from single-crystal synchrotron X-ray diffraction measurements at 16 K. The crystal structure formally contains a negatively charged framework with cations and neutral molecules in the voids. However, the CD suggests that the framework is close to neutral, and therefore qualitative conclusions based on formal charge counting, e.g., about guest inclusion properties, will be incorrect. There are considerable differences in the charge distributions of the three unique benzenedicarboxylic acid linkers, which are widely used in coordination polymers. This suggests that the electrostatic properties of coordination polymer cavities, and thereby their inclusion properties, are highly tunable. The electron density topology shows that the tetrahedrally coordinated Co atom has an atomic volume which is 15% larger than that of the octahedrally coordinated Co atom. The crystal structure has both ferromagnetic and antiferromagnetic interactions, but no direct metal-metal bonding is evidenced in the CD. The magnetic ordering therefore takes place through superexchange in the oxygen bridges and the aromatic linkers. Bonding analysis of the experimental CD reveals that two oxygen atoms, O(1) and O(11), have significant covalent contributions to the metal-ligand bonding, whereas all other oxygen atoms have closed-shell interactions with the metals. This indicates that these two oxygen atoms are the key mediators of the magnetic ordering.
RESUMEN
BACKGROUND: The role of Mycoplasma genitalium in the pathogenesis of pelvic inflammatory disease has not been characterized. METHODS: Sera from 308 infertile women were investigated for antibodies to M. genitalium by immunoblotting. Women with tubal factor infertility (TFI) made up 132 of the patients, 67 of the women had an infertile male partner and 109 were infertile for unknown reasons. RESULTS: Of the TFI patients 29 (22.0%) were seropositive to the major adhesin, MgPa, of M. genitalium versus 11 (6.3%) in the group of women with normal tubes. No cross-reactions between MgPa and P1 of the related Mycoplasma pneumoniae were found. Besides, MgPa positive sera were confirmed by immunoblotting using a cloned fragment of the C-terminal part of MgPa specific to M. genitalium. Chlamydia trachomatis is known to be able to cause infertility as a result of salpingitis. Therefore, the sera were tested against C. trachomatis using a commercial ELISA test. Seventy-five (56.8%) of the TFI patients were seropositive to C. trachomatis. Eight (27.6%) TFI patients seropositive to MgPa were negative to C. trachomatis. CONCLUSIONS: This study indicates that M. genitalium may be an independent risk factor in the development of an inflammatory process leading to scarring of the uterine tubes in women and thereby causing infertility.