[Non-viral infections of the liver]. / Nichtvirale Infektionen der Leber.

Non-viral infections of the liver are rare to very rare compared to viral infections. They can be caused by various bacteria, helminths, protozoa, and fungi, often leading to liver involvement during dissemination. Some of these infections affect in particular immunocompromised individuals, while others need to be considered in the differential diagnostic work-up in patients returning from tropical countries. In cases where the infection occurs through oral ingestion of eggs, such as in cystic and alveolar echinococcosis, the liver is often the most commonly affected organ. Due to the diversity of non-viral liver infections and their varied clinical manifestations, a comprehensive discussion of all potential pathogens and their effects is not within the scope of this article. Therefore, only a few of these conditions will be discussed in more detail.

Strong neutrino cooling by cycles of electron capture and ß- decay in neutron star crusts.

The temperature in the crust of an accreting neutron star, which comprises its outermost kilometre, is set by heating from nuclear reactions at large densities, neutrino cooling and heat transport from the interior. The heated crust has been thought to affect observable phenomena at shallower depths, such as thermonuclear bursts in the accreted envelope. Here we report that cycles of electron capture and its inverse, ß(-) decay, involving neutron-rich nuclei at a typical depth of about 150 metres, cool the outer neutron star crust by emitting neutrinos while also thermally decoupling the surface layers from the deeper crust. This 'Urca' mechanism has been studied in the context of white dwarfs and type Ia supernovae, but hitherto was not considered in neutron stars, because previous models computed the crust reactions using a zero-temperature approximation and assumed that only a single nuclear species was present at any given depth. The thermal decoupling means that X-ray bursts and other surface phenomena are largely independent of the strength of deep crustal heating. The unexpectedly short recurrence times, of the order of years, observed for very energetic thermonuclear superbursts are therefore not an indicator of a hot crust, but may point instead to an unknown local heating mechanism near the neutron star surface.