In-vitro and in-vivo evaluation of the antistaphylococcal activity of S-5556, a new 16-membered macrolide

During recent years, a resurgence of interest in the macrolides had led to the discovery of new derivatives of erythromycin with improved antibacterial activity and pharmacokinetic properties. In this study the in-vitro and in-vivo antistaphylococcal activity of S-5556, a 16-membered macrolide, was evaluated. In vitro, S-5556 was slightly less active than erythromycin against methicillin-susceptible Staphylococcus aureus. In contrast, it had superior activity for methicillin-resistant S. aureus (MRSA); several of these strains with inducible resistance to the macrolides-lincosamides-streptogramins group were susceptible to S-5556 whereas erythromycin was inactive. The combination of S-5556 with oxatillin was synergic for most MRSA strains tested. In vivo, a single prophylactic dose of S-5556 prevented 75%-100% of the cases of acute staphylococcal subcutaneous foreign body infection in a guinea pig-model. In a rat-model of chronic implant infection due to a methicillin- and erythromycin-resistant S. aureus strain, S-5556 significantly decreased the bacteria] concentration around the foreign material, however resistant mutants emerge

Transient domain walls and lepton asymmetry in the Left-Right symmetric model

It is shown that the dynamics of domain walls in Left-Right symmetric models, separating respective regions of unbroken SU(2)_L and SU(2)_R in the early universe, can give rise to baryogenesis via leptogenesis. Neutrinos have a spatially varying complex mass matrix due to CP-violating scalar condensates in the domain wall. The motion of the wall through the plasma generates a flux of lepton number across the wall which is converted to a lepton asymmetry by helicity-flipping scatterings. Subsequent processing of the lepton excess by sphalerons results in the observed baryon asymmetry, for a range of parameters in Left-Right symmetric models.Comment: v2 version accepted for publication in Phys. Rev. D. Discussion in Introduction and Conclusion sharpened. Equation (12) corrected. 16 pages, 3 figure files, RevTeX4 styl

Efficient Content-based Image Retrieval in Digital Picture Collections Using Projections: (Near)-Copy location

Digital storage of large photo collections opens the way to computer-aided queries based on visual rather than thematic search patterns. The objective of our queries in this research was the 19th-century mass-produced studio portrait or carte-de-visite, whose front and back sides provide a testbed for gray level and binary images classes. We established a ground truth for detecting highly similar images (former copies) in different classes of B/W images. The results will serve as a reference benchmark for yet to be developed visual search methods. The similarity measure used for locating near-copies was the average distance in pixel intensity for shifted image pairs with normalized position, orientation, resolution and lighting. To measure the performance of possible hierarchical comparison and ranking protocols, we scanned in test sets of known copies and near-copies together with over a thousand similar format pictures. The results show that projections are highly effective and effic..