Partículas podem ser separadas em campos elétricos quando forças eletrostáticas ultrapassam a força devido à gravidade. Para partículas condutoras, o lift-off ocorre quando o campo elétrico gera carga a ser transferida de uma superfície aterrada para a partícula, e a partícula carregada é então separada no campo elétrico; este mecanismo ocorre com qualquer polaridade do campo elétrico. Para partículas isolantes perfeitas, esta transferência de carga não pode ocorrer, mas as partículas que já estão carregadas podem ser separadas por um campo elétrico de polaridade apropriada (mas não outra polaridade). Experimentos foram conduzidos, em condições ambiente e controlados ambientalmente, nos lift-off de partículas compostas de diferentes materiais, e os resultados para os necessários campos elétricos limites para o lift-off foram comparados a previsões baseadas em modelos de partículas condutoras e isolantes. Os resultados para uma partícula de alumínio estão em acordo com o modelo de partícula condutora. Nos casos de partículas isolantes, a separação das partículas de politetrafluoretileno (PTFE) mostra-se consistente com o modelo de partícula isolante, mas partículas de Nylon® e de vidro exibiram comportamento dependente da umidade. Em baixa umidade, partículas de Nylon® e de vidro são separadas de acordo com o modelo de partícula isolante, enquanto que à umidade elevada, o comportamento de separação surpreendentemente seguiu o modelo de partícula condutora. Sugere-se que a elevada umidade, a natureza hidrofílica das superfícies das partículas de Nylon® e de vidro levou à formação de uma camada superficial condutora que facilita a transferência de carga do mesmo modo que uma partícula de metal.

Particles can be lifted in electric fields when the electrostatic forces overcome the force due to gravity. For conducting particles, the lift-off occurs when the electric field causes charge to be transferred from a grounded surface to the particle, and the charged particle is then lifted in the electric field; this mechanism occurs with either polarity of the electric field. For perfectly insulating particles, this charge transfer cannot occur, but the particles that are already charged can be lifted by an electric field of the appropriate polarity (but not the other polarity). Experiments were carried out, under ambient and environmentally controlled conditions, on the lift-off of particles composed of different materials, and the results for the threshold electric fields necessary for lift-off were compared with predictions based on the conducting and insulating particle models. Results for an aluminum particle are in agreement with the conducting particle model. In the case of insulating particles, the lifting of polytetrafluoroethylene (PTFE) particles is consistent with the insulating particle model, but Nylon® and soda-lime glass exhibit humidity-dependent behavior. At low humidity, Nylon® and soda-lime glass particles are lifted in accordance with the insulating particle model, while at high humidity, the lifting behavior surprisingly follows the conducting particle model. It is suggested that at high humidity, the hydrophilic nature of the Nylon® and soda-lime glass particle surfaces leads to a conducting surface layer of water that facilitates charge transfer similar to a metal particle.

The levels of IgE and IgG4 increased strongly between cohorts, indicating a dynamic immunological situation, but no immediate impact on infection levels. Morbidity was little specific abdominal discomfort was reported by 61%, diarrhoea by 33% of the subjects; mild hepatomegaly was found in 16%, splenomegaly in 0.5%. No relation to egg counts was observed for any symptom. This mild morbidity may be due to the recent nature of the focus. In the first cohort, the percentage of people with negative egg counts ten weeks after treatment was only 18%, though egg counts declined strongly. Antigen detection confirmed these results. Praziquantel treatment provoked transient but impressive side effects (colics, vomiting, urticaria, aedema), the occurrence of which correlated with intensity of infection. Cure rates in subsequent cohorts were followed up shorter after treatment but remained low. Reinfection nevertheless oppears limited. This lower drug efficacy may be due to very rapid reinfection and/or to the lack of immunity in the population, but also reduced susceptibility of the local parasite strain must be considered and studied.