Ross River virus disease in two Dutch travellers returning from Australia, February to April 2015

We report two cases of Ross River virus (RRV) infection in Dutch travellers who visited Australia during February to April 2015. These cases coincided with the largest recorded outbreak of RRV disease in Australia since 1996. This report serves to create awareness among physicians to consider travel-related RRV disease in differential diagnosis of patients with fever, arthralgia and/or rash returning from the South Pacific area, and to promote awareness among professionals advising travellers to this region

In-Situ Nuclear Magnetic Resonance Investigation of Strain, Temperature, and Strain-Rate Variations of Deformation-Induced Vacancy Concentration in Aluminum

Critical strain to serrated flow in solid solution alloys exhibiting dynamic strain aging (DSA) or Portevin–LeChatelier effect is due to the strain-induced vacancy production. Nuclear magnetic resonance (NMR) techniques can be used to monitor in situ the dynamical behavior of point and line defects in materials during deformation, and these techniques are nondestructive and noninvasive. The new CUT-sequence pulse method allowed an accurate evaluation of the strain-enhanced vacancy diffusion and, thus, the excess vacancy concentration during deformation as a function of strain, strain rate, and temperature. Due to skin effect problems in metals at high frequencies, thin foils of Al were used and experimental results correlated with models based on vacancy production through mechanical work (vs thermal jogs), while in situ annealing of excess vacancies is noted at high temperatures. These correlations made it feasible to obtain explicit dependencies of the strain-induced vacancy concentration on test variables such as the strain, strain rate, and temperature. These studies clearly reveal the power and utility of these NMR techniques in the determination of deformation-induced vacancies in situ in a noninvasive fashion.

Determination of the nonlinear optical susceptibility c(2) of surface layers by sum and difference frequency generation in reflection and transmission

The theor. investigation of sum and difference frequency generation in thin surface layers with rotational symmetry led to formulas which connected the generated light intensities to the surface 2nd-order nonlinear susceptibility tensor. A max. of 7 tensor components was detd. in the lowest symmetry case. Measurements in transmission were esp. useful since they allowed easy variation of both polarization and angle of incidence. Large signal enhancements are expected for total internal reflection geometries. A consistent set of c(2) tensor components for a thin layer of Rhodamine 6G adsorbed on fused SiO2 was found based on data from reflection and transmission measurements