According to the International Energy Agency, biorefinery is “the sustainable processing of biomass into a spectrum of marketable bio-based products (chemicals, materials) and bioenergy (fuels, power, heat)”. In this review, we survey how the biorefinery approach can be applied to highly porous and nanostructured materials, namely aerogels. Historically, aerogels were first developed using inorganic matter. Subsequently, synthetic polymers were also employed. At the beginning of the 21st century, new aerogels were created based on biomass. Which sources of biomass can be used to make aerogels and how? This review answers these questions, paying special attention to bio-aerogels’ environmental and biomedical applications. The article is a result of fruitful exchanges in the frame of the European project COST Action “CA 18125 AERoGELS: Advanced Engineering and Research of aeroGels for Environment and Life Sciences”.

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A b s t r a c t. Due to the absence of a suitable method and standardized procedures, the root systems of plants have been evaluated to a much lesser extent than aboveground organs. The aim of this article is (i) to provide a detailed description and thus standardization of an upgraded procedure of electrical capacitance measurement for evaluating the size of the root system of plants in situ, which allows for a reassessment to be made during the growing season and subsequent harvest of seeds for the planting of selected progenies, (ii) to demonstrate, through a standardized methodological protocol, the applicability of root electrical capacitance measurement as a field phenotyping method for the selection of superior root systems to improve crop abiotic stress tolerance and resource efficiency, (iii) to suggest a standardized methodological protocol for the application of electrical capacitance measurements in breeding nurseries, and (iv) to discuss the methodological aspects, development and limitations of this method. A methodological overview of the use of electrical capacitance to measure plant root systems, which emerged from working groups directed by the author of this unique method, is presented along with a standardized protocol. An overview of the application of electrical capacitance measurements of roots in breeding is shown along with some examples of successful applications.K e y w o r d s: root system, drought tolerance, varieties, yield

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For many years, scientists have been searching for nondestructive methods for the measurement of plant root system parameters. The measurement of electrical capacitance (EC) across the root has been proposed as one such nondestructive method. This article presents a study on the determination of relationships between EC measurement and the shape and size of the electrodes immersed in medium that are used for measurement. Measurement of EC and the parameters characterizing root systems of 1-year-old seedlings of the common beech Fagus sylvatica L. was conducted under laboratory conditions. The measurements of EC were performed between seedling root systems and two different electrodes in the form of a cylinder or a rectangular plate. Statistically significant correlations were found between the capacitance and root system parameters in both the variants; however, the correlations were higher in the case of the flat rectangular plate. Correlation coefficient (r) between EC and total root length was  0.688 for cylindrical electrode and  0.802 for rectangular plate, for total root area 0.641 and 0.818, and for dry weight of root system 0.502 and 0.747. The best-fitted linear regression relationships between the EC and the measured parameters were characterized by low determination coefficients in variants with cylindrical electrodes, and higher with flat rectangular plate electrodes. The results indicated that a two-dielectric media concept is a better model than Dalton's model when attempting to interpret the behavior of root and soil capacitance. The different electrodes probably allow root capacitance measurements to be interpreted from different aspects. However, this hypothesis requires further verification.