This paper analyses the viability of different solutions to passively augment the axial stiffness of a horizontal axis radial levitation passive magnetic bearing (PMB) with topology previously studied. The zero-field cooling (ZFC) of high-temperature superconductor (HTS) bulks promotes higher magnetic impulsion and levitation forces and lower electromagnetic losses than with the field-cooling (FC), but on the other hand, the guiding stability is much lower than with FC. Because of stability reasons, FC was adopted in most superconducting maglev systems. The trend of this research group has been to develop an HTS ZFC horizontal axis radial levitation PMB presenting notable levitation forces with reduced electromagnetic losses, defined by a topology that creates guiding stability. Previous work has shown that even optimizing the bearing geometry to maximize magnetic guidance forces, could not be enough to guarantee the axial stiffness required for many applications. First, the extent to which guidance forces are augmented by increasing the number of HTS bulks in the stator is evaluated. Then, the axial stiffness augmentation by passively adding two limiting permanent magnet (PM) rings is evaluated. Results show that the axial stiffness is highly augmented by adding limiting PM rings with no significant additional investment. This change enables using the studied ZFC superconducting PMB in high-precision axial stability applications, such as precision gyroscopes, horizontal axis propellers and turbines.

We have developed a family of N-alkyl-nitrobenzamides that exhibit promising antitubercular ac-tivities. These compounds are a simplification of the structure of known inhibitors of DprE1, an essential Mtb enzyme and an emergent anti-TB target. The compounds were obtained by a simple synthetic methodology and their antitubercular, cyto-toxicity and stability were studied. The most active compounds were the 3,5-dinitro and the 3-nitro-5-trifluoromethyl derivatives. Lipophilicity was shown to be a main parameter modulating activity within each family. The most active compound presented MIC of 16 ng/mL and had in-termediate lipophilicities. The activity was also studied in a macrophage model of infection. In this model the compounds with chain lengths of 6 and 12 carbon atoms presented the best results, ex-hibiting activity profiles comparable to isoniazid. Docking studies performed suggested that the fit of our highly active compounds to the DprE1 binding pocket was very similar to the literature compounds. Furthermore, the metrics used in the analysis were able to distinguish between the families of the highly and least active compounds. Assessment of susceptibility over multiple species and computational together with the structure of the compounds are complementary information that supports DprE1 as a likely target of action for this type of compounds.