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The use of natural organic correctives is a current agricultural practice that may have advantages for the production of plants in contaminated soils. Cork powder is a natural sub-product of the cork industry that has several potential benefits compared to more commonly used soil amendments. In this work, an evaluation was performed of the use of cork powder (a non-conventional organic residue) and horse manure (traditionally used in agriculture) to control the availability of potentially toxic elements in artificially contaminated soils. Four concentrations were used for each element: Cr (100 to 800 mg kg−1), Ni (37.5 to 300 mg kg−1), Zn (150 to 1200 mg kg−1), Cd (1.5 to 12 mg kg−1) and Pb (150 to 1200 mg kg−1). The accumulation of these elements in lettuce plants grown in pots under controlled conditions was evaluated. With the exception of Cd, no significant differences were detected in the absorption of the different elements by lettuce plants at the studied amounts of correctives applied (1% for cork powder and 0.5% for horse manure). Cadmium was the element that accumulated most in lettuce. Cork powder was shown to be less effective than horse manure in controlling the bioavailability of these elements in the soil. Further tests with chemically modified cork products could improve its efficiency.

UID/Multi/04378/2020 Electronic noses (e-noses) mimic the complex biological olfactory system, usually including an array of gas sensors to act as the olfactory receptors and a trained computer with signal-processing and pattern recognition tools as the brain. In this work, a new stimuli-responsive material is shown, consisting of self-assembled droplets of liquid crystal and ionic liquid stabilised within a fish gelatin matrix. These materials change their opto/electrical properties upon contact with volatile organic compounds (VOCs). By using an in-house developed e-nose, these new gas-sensing films yield characteristic optical signals for VOCs from different chemical classes. A support vector machine classifier was implemented based on 12 features of the signals. The results show that the films are excellent identifying hydrocarbon VOCs (toluene, heptane and hexane) (95% accuracy) but lower performance was found to other VOCs, resulting in an overall 60.4% accuracy. Even though they are not reusable, these sustainable gas-sensing films are stable throughout time and reproducible, opening several opportunities for future optoelectronic devices and artificial olfaction systems. publishersversion published

In this work, we describe the development of a computational screening approach for tripeptide-dipeptide co-assembly. Studies are carried out both in water and in oil–water mixtures, to evaluate possible candidates that give rise to hydrogels or more stable emulsions, respectively, through nanofibre formation. The results give rise to design rules for the identification of promising systems for numerous types of soft materials. The possibility of achieving innovative functional materials through the co-assembly of tripeptides and dipeptides is studied. In particular, coarse-grained simulations allowed for the extraction of some promising dipeptides that, together with H-aspartyl-phenylalanyl-phenylalanine-OH (DFF), are able to act as hydrogelators or emulsifiers with superior characteristics relative to DFF on its own.

We report on the biocatalytic activation of a self-assembling (unprotected) tripeptide to stabilize oil-in-water emulsions on-demand. This is achieved by the conversion of a phosphorylated precursor into a hydrogelator using alkaline phosphatase (AP) as the trigger. The rate of conversion, controlled by the amount of enzyme used, is shown to play a key role in dictating the morphology of the nanofibrous networks produced. When these amphiphilic tripeptides are used in biphasic mixtures, nanofibers are shown to self-assemble not only at the aqueous/organic interface but also throughout the surrounding buffer, thereby stabilizing the oil-in-water droplet dispersions. The use of enzymatic activation of tripeptide emulsions gives rise to enhanced control of the emulsification process because emulsions can be stabilized on-demand by simply adding AP. In addition, control over the emulsion stabilization can be achieved by taking advantage of the kinetics of dephosphorylation and consequent formation of different stabilizing nanofibrous networks at the interface and/or in the aqueous environment. This approach can be attractive for various cosmetic, food, or biomedical applications because both tunability of the tripeptide emulsion stability and on-demand stabilization of emulsions can be achieved.

Plants need a whole range of mineral elements as nutrients in order to grow. Some of these essential elements are needed in higher amounts (macronutrients), and others in lower amounts (micronutrients). They are absorbed by the roots, and distributed through the different plant parts. The presence of heavy metals, such as cadmium, can disturb this equilibrium, and can affect both the uptake of several of these elements by the roots and/or its distribution through the other plant parts. This can be due to several effects, such as competition with the same transporters, a disturbance in water uptake, or affecting key enzymes in the transport process. Although there are many publications concerning the effect of Cd on nutrient uptake, the results are sometimes contradictory, due to the fact that the effects are highly dependent on plant species and experimental conditions, among other factors. In this chapter we present an update on the main effects caused by Cd in mineral nutrient uptake, describing the elements that are reported to be most affected, and the known mechanisms that can cause the nutrient imbalance.

Different types of heating systems have been developed lately, representing a growing interest in both the academic and industrial sectors. Based on the Joule effect, fibrous structures can produce heat once an electrical current is passed, whereby different approaches have been followed. For that purpose, materials with electrical and thermal conductivity have been explored, such as carbon-based nanomaterials, metallic nanostructures, intrinsically conducting polymers, fibers or hybrids. We review the usage of these emerging nanomaterials at the nanoscale and processed up to the macroscale to create heaters. In addition to fibrous systems, the creation of composite systems for electrical and thermal conductivity enhancement has also been highly studied. Different techniques can be used to create thin film heaters or heating textiles, as opposed to the conventional textile technologies. The combination of nanoscale and microscale materials gives the best heating performances, and some applications have already been proven, even though some effort is still needed to reach the industry level., This article is a result of the project LH4Auto—Lighting and Heating System for Automotive, code POCI-01-0271-FEDER-049652, under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF)

We report on-demand formation of emulsions stabilised by interfacial nanoscale networks. These are formed through biocatalytic dephosphorylation and self-assembly of Fmoc(9-fluorenylmethoxycarbonyl)-dipeptide amphiphiles in aqueous/organic mixtures. This is achieved by using alkaline phosphatase which transforms surfactant-like phosphorylated precursors into self-assembling aromatic peptide amphiphiles (Fmoc-tyrosine-leucine, Fmoc-YL) that form nanofibrous networks. In biphasic organic/aqueous systems, these networks form preferentially at the interface thus providing a means of emulsion stabilisation. We demonstrate on-demand emulsification by enzyme addition, even after storage of the biphasic mixture for several weeks. Experimental (Fluorescence, FTIR spectroscopy, fluorescence microscopy, electron microscopy, atomic force microscopy) and computational techniques (atomistic molecular dynamics) are used\ud to characterise the interfacial self-assembly process.