Maria C.F.C. Felinto

Mechanoluminescence of Coordination Compounds

Mechanoluminescence (ML) involves all luminescence phenomena induced by mechanical action on solids. In this case, a wide varieties of mechanical stimuli, such as compressing, stretching, static loading (pressure-step), pressure pulse, cleaving, rubbing, and grinding, might induce the excitation of solids, yielding luminescence phenomena. The present chapter discusses on mechanoluminescent properties of transition metal and lanthanide coordination compounds. The principal aim of this chapter is to describe the recent facts about the mechanisms of mechanoluminescence and their correlation with structural properties. It will be also presented a concise overview on the latest progress made on the current variety of ML coordination compounds or materials based on transition and lanthanide metals. The recent studies in this area may lead to the development of ML materials for smart optical sensors for real-time damage detections, monitoring civil and military structures, luminescent probes for biological applications, and lightning systems.

Endophytic bacteria and rare earth elements; promising candidates for nutrient use efficiency in plants

Abstract Nutrient use efficiency (NUE) depends on the plant’s ability to take up nutrients efficiently from the soil, but also depends on internal transport, storage and remobilization of nutrients. Nitrogen (N) is a fundamental element regulating plant growth and development. Plants have evolved inorganic and organic N-uptake systems to cope with heterogeneous N availability in the soil. However, NUE is dependent on root growth and root architecture. Endophytic bacteria have a direct influence on root growth and increase nutrient uptake. Under reciprocal exchange, trading carbon for nutrients, plant and bacteria establish a symbiotic association. In this chapter we will address how endophytic bacteria might contribute to efficient nutrient uptake, especially organic nitrogen, through bacterial cell degradation or by externally activating nitrogen transporters. Also, here we propose the use of rare earth elements as an option for improving NUE in plants and their possible use as fertilizers.