No abstract

Detecting and monitoring air-polluting gases such as carbon monoxide (CO), nitrogen oxides (NOx), and sulfur oxides (SOx) are critical, as these gases are toxic and harm the ecosystem and the human health. Therefore, it is necessary to design high-performance gas sensors for toxic gas detection. In this sense, graphene-based materials are promising for use as toxic gas sensors. In addition to experimental investigations, first-principle methods have enabled graphene-based sensor design to progress by leaps and bounds. This review presents a detailed analysis of graphene-based toxic gas sensors by using first-principle methods. The modifications made to graphene, such as decorated, defective, and doped to improve the detection of NOx, SOx, and CO toxic gases are revised and analyzed. In general, graphene decorated with transition metals, defective graphene, and doped graphene have a higher sensibility toward the toxic gases than pristine graphene. This review shows the relevance of using first-principle studies for the design of novel and efficient toxic gas sensors. The theoretical results obtained to date can greatly help experimental groups to design novel and efficient graphene-based toxic gas sensors.

A c c e p t e d M a n u s c r i p t 2 Induction of anhydrobiosis and storage stability of entomopathogenic nematodes are influenced by moisture availability. Decreasing moisture content in diatomaceous earth pellets containing Steinernema glaseri NJ-43 strain and its effect on survival time and infectivity of the nematode was determined. Pelletisation was performed in a vortex mixer, using diatomaceous earth Celite ® 209 as desiccant material. Pellets were stored at room temperature (23±2 °C) and high relative humidity (96-100%). Nematode survival and infectivity against last instar greater wax moth, Galleria mellonella, were tested daily. Initial average and average equilibrium moisture content in pellets were 66.7% and 13.6%, respectively, and the IJ's mean survival time was 8.8 days. A moisture transfer model based on diffusion and evaporation was evaluated to predict moisture fluctuations within the pellets. We concluded that 84% of variation in S. glaseri infectivity on G. mellonella larvae was explained by the survival of the nematode whereas 52% of variation in S. glaseri survival was explained by the loss of moisture from the pellets. The moisture transfer model achieved 78% reliability in predicting moisture content and fluctuations. Therefore, the mechanisms of moisture diffusion and evaporation from the surface to the surrounding atmosphere contribute significantly to moisture loss from the pellets.

No abstract

Cruz-Martínez H., Ruiz-Vega J., Matadamas-Ortíz P.T., Cortés-Martínez C.I., Rosas-Diaz J. (2017): Formulation of entomopathogenic nematodes for crop pest control -a review. Plant Protect. Sci., 53: 15-24.The different materials and methods used to develop biopesticides with entomopathogenic nematodes (EPNs) still limit the quality of the final product, reducing field efficacy and complicating application strategies. Therefore, the objective of this review is to identify priority areas to improve the EPN formulation process based on the scientific and technological research developed so far. The results show great progress in the EPN survival time, from 7 days to 180 days, through two types of formulations: water dispersible granules and calcium alginate capsules. Also, EPNs formulated and applied as insect cadavers showed higher efficacy for the pest control than the EPNs applied in an aqueous solution. We consider that the priority areas of research are: automated massive formulation and exploration of new additives with better properties that may lead to increase the infectivity in the field. It is concluded that the study of these aspects requires a systemic approach with greater involvement of the invertebrate physiology and systems modelling disciplines.