Suppression of rupture in thin, nonwetting liquid films

Stabilization against the rupture and breakup of thin, nonwetting liquid films spread on surfaces is generally sought by modification of equilibrium interfacial properties. A mechanism for suppressing rupture in such films that uses surface-attached polymers togetherwithfree chains in the bulk of the film is reported. Films of an oligostyrene liquid, which rupture within several minutes when spread on a silicon wafer, may be stabilized for many months by a polystyrene brush attached to the substrate, together with some free polystyrene in the liquid. The effect may arise from entanglements of the free chains with the immobilized brush.     

Spread of viruses through the food chain

Food associated viruses are responsible for a high number of infectious diseases in man, mainly gastroenteritis and hepatitis. The three most important viral agents are noroviruses (NV) (formerly known as Norwalk-like viruses), Rotavirus (RV) and Hepatitis A-Virus (HAV). The numbers of infections in man were in 2002 according to the Robert Koch-Institut for NV and RV 50,000, respectively, and for HAV 1,500, slightly decreasing in 2003. The rate of foodborne infections caused by viruses can only be estimated (appr. 20% of total cases). On the other hand only a very small part of viral gastroenteritis can be diagnosed and notified. Besides the direct infection through contaminated food the human to human infection is the most important source, also responsible for outbreaks. There is at the moment no routine diagnostic tool available for the detection of viruses in food because of the lack of standardized methods. For NV, one of the most important foodborne (live bivalve molluscs) viral pathogens, indicator organisms are in use. There is a scientific evaluation in different member states concerning the value of bacterial indicators vs. bacteriophages. In addition to foodborne viruses (via faecal contamination present in the food chain) there are emerging zoonotic viral agents. Food may be a vector for this agents depending on the production structures (e.g. SARS or influenca).