The aim of the present experiment was to investigate the influence of silver nanoparticles on Fusarium culmorum (W.G. Smith) Sacc. (FC) spores. The silver nanoparticles were produced by the high-voltage arc discharge method. To test the effect of silver nanoparticles on FC spores, 3 parameters were tested. One of these parameters was the vegetative mycelial growth in 2 experiments. The first involved the growth of FC spores on potato dextrose agar (PDA) medium after contact with 0.12–10 ppm of silver nanoparticles, and the second the growth of spores after contact with 0.12–2.5 ppm solutions of silver, but with culturing on 3 types of media (PDA, nutrient-poor PDA, and agar) instead. The next parameter was the formation of spores after the mycelia were cultured. The last parameter was spore germination in a 2.5 ppm solution of silver nanoparticles. A significant reduction in mycelial growth was observed for spores incubated with silver nanoparticles. This relationship was dependent on the incubation time and type of growth medium, but did not depend significantly on the concentration of silver nanoparticles up to 2.5 ppm. The sporulation test showed that, relative to control samples, the number of spores formed by mycelia increased in the culture after contact with silver nanoparticles, especially on the nutrient-poor PDA medium. The 24 h incubation of FC spores with a 2.5 ppm solution of silver nanoparticles greatly reduced the number of germinating fragments and sprout length relative to the control.

The aim of the investigation was to assess the influence of commercial and carboxylated multi-walled carbon nanotubes (MWCNTs) on conidia of the entomopathogenic fungus Paecilomyces fumosoroseus. The commercial MWCNTs had an external diameter of about 40–60 nm, a length of 300–600 nm, a specific density of 140 to 300 g/dm³ and a carbon content of above 80%. Carboxylated MWCNTs were obtained by oxidizing commercial MWCNT by heating in HNO₃, filtering, washing with water and drying. Conidia after different times of contact (from 1 to 865 hours) with nanomaterials in aqueous solutions were cultured for linear and biomass growth. Growth and sporification of mycelium after culture were evaluated. MWCNTs are not greatly cytotoxic for P. fumosoroseus conidia in the applied concentrations. The linear growth of mycelium obtained from conidia after contact with nanotubes was inhibited only in 2 (out of 18) cases (ones for both kinds of nanotubes). Carboxylated nanotubes did not inhibit biomass growth at all, but commercial nanotubes inhibited biomass growth in 2 cases. Sporification was the feature most strongly modified by carbon nanotubes. The commercial nanotubes again more strongly limited sporification of mycelium than carboxylated nanotubes did. The relatively greater influence of commercial versus carboxylated nanotubes was observed in the experiments.

The commonly accepted theory of light-induced atomic desorption (LIAD) [S. N. Atutov et al., Phys. Rev. A 60, 4693 (1999)] explains the dynamics of this effect by referring to a light-enhanced diffusion process proceeding in the absorbing medium. On the other hand, recently performed measurements show that in siloxane films which are used in LIAD experiments, the characteristic time of diffusion is extremely short (a fraction of 1 s) compared to the duration of the LIAD effect (hundreds of seconds). This is in contradiction to the conceptual basis of the theory of Atutov et al. that requires the characteristic diffusion time to be sufficiently long. What is more, the theory of Atutov et al. relies on an unjustified assumption about the dependence of the diffusion coefficient on the light intensity. In consequence, the theoretical results of Atutov et al. yield unsatisfactory predictions and do not fit well with experimental data. In this paper, we consider a partially illuminated siloxane-coated cell and propose an alternative theory of LIAD dynamics based on an assumption about lateral diffusion proceeding in the siloxane coating. Our theory provides a unique solution for the desorbed atoms’ density regardless of the power of the laser light, explains the lengthy duration of LIAD, and accurately reproduces experimental results. A reasoning which explains how the boundary condition at the siloxane surface is established by the incident light gives us a proper relation between the desorbed atoms’ density and the intensity of the desorbing light.

Kinetic energy distributions of alkali-metal atoms (sodium and rubidium) desorbed from poly-dimethylsiloxane coated glasses via visible $\left(532\text{nm}\right)$ and near-infrared $\left(1064\text{nm}\right)$ laser irradiation are determined. In each case the time-of-flight spectra show a single desorption peak. In the case of sodium the mean kinetic energy of the desorbing atoms depends on the photon energy and linearly on the laser fluence. Evanescent-wave desorption measurements show that the origin of the desorbed atoms is within the bulk of the thin organic film. The results are discussed in terms of electronic excitation and resonant heating, providing values of barrier heights for desorption from PDMS. The observed small barrier heights explain the weak light intensity necessary for light-induced atomic desorption from such systems.