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The cuticle forms an effective barrier protecting plants from water loss. Its permeability to water and other compounds significantly differs between species, types of cuticle (stomatous, astomatous), and can be affected by a wide variety of ambient conditions. Enzymatic isolation of the leaf cuticle allows obtaining intact cuticles for permeability measurements. However, the most available gravimetric method, which is used for the assessment of water permeability of isolated cuticles, requires a relatively large area of the cuticle and does not allow the determination of membrane heterogeneity. We propose a new method for the determination of water permeance based on an on-line detection of water flux from a liquid phase to the atmosphere through isolated leaf cuticles in semi-flow chambers. This approach is new in using the phenomenon of surface plasmon resonance for the detection of the liquid phase refractive index affected by water vapor. Isolated cuticles of the leaves of Ficus elastica and an artificial polyethersulfone membrane were used for method evaluation. The composition of cuticular wax and its influence on cuticular permeability was also studied. It has been confirmed that the application of the surface plasmon resonance principle can be used for the assessment of leaf cuticle water permeability and heterogeneity.

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Thermo-catalytic pyrolysis is considered as a promising process for the chemical recycling of waste polymeric materials aiming at converting them into their original monomers or other valuable chemicals. In this regard, process parameters and reactor type can play important roles for an enhanced recovery of the desired products. Polystyrene (PS) wastes are excellent feedstocks for the chemical recycling owing to the capability of PS to be fully recycled. In this respect, the present work deals with the thermo-catalytic pyrolysis of PS in batch and semi-batch reactor setups. The main goal was to perform a comprehensive study on the depolymerisation of PS, thereby investigating the effect of reactor type, catalyst arrangement, feed to catalyst ratio and residence time on the yields of oil and styrene monomer (SM). A further goal was to identify the optimum operating conditions as well as reactor type for an enhanced recovery of oil and SM. It was demonstrated that the semi-batch reactor outperformed the batch reactor in terms of oil and SM yields in both thermal (non-catalytic) and catalytic tests performed at 400°C. Furthermore, it was shown that the layered arrangement of catalyst (catalyst separated from PS) produced a higher amount of oil with higher selectivity for SM as compared to the mixed arrangement (catalyst mixed with PS). Moreover, the effect of carrier gas flowrate on the product distribution was presented.

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BACKGROUND: The plant cuticle represents one of the major adaptations of vascular plants to terrestrial life. Cuticular permeability and chemical composition differ among species. Arabidopsis thaliana is a widely used model for biochemical and molecular genetic studies in plants. However, attempts to isolate the intact cuticle from fresh leaves of Arabidopsis have failed so far. The goal of this study was to optimise an enzymatic method for cuticle isolation of species with a thin cuticle and to test it on several A. thaliana wild types and mutants. RESULTS: We developed a method for isolation of thin cuticles that allows reducing the isolation time, the separation of abaxial and adaxial cuticles, and avoids formation of wrinkles. Optical microscopy was used for studying cuticle intactness and scanning electron microscopy for visualisation of external and internal cuticle structures after isolation. Wax extracts were analysed by GC-MS. Isolation of intact cuticle was successful for all tested plants. The wax compositions (very-long-chained fatty acids, alcohols and alkanes) of intact leaves and isolated cuticles of wild type Col-0 were compared. CONCLUSIONS: We conclude that the optimised enzymatic method is suitable for the isolation of A. thaliana adaxial and abaxial cuticles. The isolated cuticles are suitable for microscopic observation. Analysis of wax composition revealed some discrepancies between isolated cuticles and intact leaves with a higher yield of wax in isolated cuticles.

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Exfoliated graphitic carbon nitride (g-C3N4) and two commercially available nanomaterials from titanium dioxide (P25 and CG300) were tested for the photocatalytic degradation of paracetamol (PAR), ibuprofen (IBU), and diclofenac (DIC). Prior to photocatalytic experiments, the nanomaterials were characterized by common methods, such as X-ray diffraction (XRD), UV-VIS diffuse reflectance spectroscopy (DRS), Fourier transformed infrared spectroscopy in attenuated total reflection mode (FTIR-ATR), transmission electron microscopy (TEM), physisorption of nitrogen, and dynamic vapor adsorption (DVS) of water. The sizes and specific surface area (SSA) of the TiO2 nanoparticles were 6 nm and 300 m2·g-1 for CG300 and 21 nm and 50 m2·g-1 for P25. The SSA of g-C3N4 was 140 m2·g-1. All photocatalytic experiments were performed under UV (368 nm), as well as VIS (446 nm) irradiation. TiO2 P25 was the most active photocatalyst under UV irradiation and g-C3N4 was the most active one under VIS irradiation. Photodegradation yields were evaluated by means of high performance liquid chromatography (HPLC) and reaction intermediates were identified using gas chromatography with mass detection (GC-MS). Paracetamol and ibuprofen were totally removed but the intermediates of diclofenac were observed even after 6 h of irradiation. Some intermediates, such as carbazole-1-acetic acid, 2,6-dichloraniline, and hydroxylated derivates of diclofenac were identified. This study showed that g-C3N4 is a promising photocatalyst for the degradation of pharmaceuticals in an aqueous environment, under visible light.

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The CE-ESI-MS/MS method for the identification, separation and determination of mushroom toxins, namely ibotenic acid, muscimol and muscarine, was developed. It proved to be sensitive and thus useful for the real sample analysis with omitting the labor and time consuming pretreatment step. The CE-ESI-MS/MS method was applied on the spiked human urine. The analytical characteristics of the proposed method, such as limits of detection, linearity and repeatability of the peak area and the migration time, were evaluated. The RSD of the migration time and peak area were from 0.93% to 1.60% and from 2.96% to 3.42%, respectively. The obtained LOD values were at the nanomolar concentration level, therefore the developed method is sufficient for the determination and quantification of studied toxins in human urine after mushroom intoxication.

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