To assess the incidence of Lyme borreliosis in Central Europe, a 12-month, prospective, population-based surveillance study of Lyme borreliosis was conducted in the Wurzburg region of central Germany, following an aggressive awareness campaign. The diagnosis of Lyme borreliosis required the presence of (i) erythema migrans (diameter > or =5 cm); (ii) lymphocytoma; or (iii) another specific manifestation including Lyme arthritis, neuroborreliosis, carditis or acrodermatitis chronica atrophicans in conjunction with serological confirmation. A total of 313 cases of Lyme borreliosis was diagnosed, giving an incidence of 111 cases/100000 inhabitants, the highest rates occurring in children and elderly adults living in wooded as opposed to agricultural areas. The incidence in city dwellers and inhabitants of rural areas was not significantly different. Erythema migrans was the only manifestation in 279 (89%) patients. Of the 34 patients with manifestations other than erythema migrans alone, 15 had arthritis, nine neuroborreliosis, six lymphocytoma, four acrodermatitis chronica atrophicans and one carditis. Children were more likely than adults to have manifestations other than erythema migrans alone. Lyme borreliosis was very common in central Germany, and one of the most frequent bacterial infections. The observation of more cases of arthritis than neuroborreliosis was similar to that in the USA. These results may be representative for many parts of central Europe and suggest the need for development of a vaccine against borreliosis caused by European strains of Borrelia species.

We present a detailed study of the tautomerization, that is, the switching of hydrogen protons, between different sites in the molecular frame of phthalocyanine (HPc) on a Ag(111) substrate by means of scanning tunneling microscopy (STM) and STM-based pump-and-sample techniques. Our data reveal that the symmetry mismatch between the substrate and the molecular frame lifts the energetic degeneracy of the two HPc tautomers. Their energy difference is so large that only one tautomer can be found in the ground state. Tip-induced tautomerization was triggered at sufficiently high bias voltages. The excited metastable HPc tautomer was found to exhibit a lifetime of at least several days, as derived from the fact that the molecule did not change back to the ground state within experimentally accessible time scales as long as noninvasive tunneling parameters were used to probe the state of the molecule. By the controlled removal of a hydrogen proton from the molecule, a four-level system was created. Pump-and-sample experiments reveal that the lifetime of the metastable positions amounts to seconds only. Current- and bias-dependent studies indicate that the presence of the STM tip modifies the potential barrier, thereby allowing for a controlled tuning of the metastable tautomer's lifetime.

We report the direct observation of a theoretically predicted magnetic ground state in a monolayer Fe on Rh(111), which is referred to as an up-up-down-down (↑↑↓↓) double-row-wise antiferromagnetic spin structure, using spin-polarized scanning tunneling microscopy. This exotic phase, which exists in three orientational domains, is revealed by experiments with magnetic probe tips performed in external magnetic fields. It is shown that a hitherto unconsidered four-spin-three-site beyond-Heisenberg interaction distinctly contributes to the spin coupling of atoms with S≥1 spins. The observation of the ↑↑↓↓ order substantiates the presence of higher-order, in particular, three-site interactions, in thin magnetic films of itinerant magnets.

Molecular electronics where single molecules perform basic functionalities of digital circuits is a fascinating concept that one day may augment or even replace nowadays semiconductor technologies. The tautomerization of molecules, that is, the bistable functional position of hydrogen protons within an organic frame, has recently been intensively discussed as a potential avenue toward nanoscale switches. It has been shown that tautomerization can be triggered locally or nonlocally, that is, by a scanning tunneling microscope (STM) tip positioned directly above or in close vicinity to the molecule. Whereas consensus exists that local switching is caused by inelastic electrons that excite vibrational molecular modes, the detailed processes responsible for nonlocal tautomerization switching and, even more important in the context of this work, methods to control, engineer, and potentially utilize this process are largely unknown. Here, we demonstrate for dehydrogenated HPc molecules on Ag(111) how to controllably decrease or increase the probability of nonlocal, hot electron-induced tautomerization by atom-by-atom designed Ag nanostructures. We show that Ag atom walls act as potential barriers that exponentially damp the hot electron current between the injection point and the molecule, reducing the switching probability by up to 83% for a four-atom wide wall. By placing the molecule in one and the STM tip in the other focal point of an elliptical nanostructure, we could coherently focus hot electrons onto the molecule that led to an almost tripled switching probability. Furthermore, single and double slit experiment based on silver atom structures were used to characterize the spatial extension of hot electron packets. The absence of any detectable interference pattern suggests that the coherence length of the hot electrons that trigger tautomerization processes is rather short. Our results demonstrate that the tautomerization switching of single molecules can remotely be controlled by utilizing suitable nanostructures and may pave the way for designing new tautomerization-based switches.