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Production of nitroaryl secondary metabolites by wood-decaying fungi of<i> Phlebia</i> spp.
No full textFilamentous fungi produce secondary metabolites with multiple biochemical activities. For wood-decaying fungi of Basidiomycota, some of these compounds may act as redox-active mediators involved in biodegradation of lignocelluloses and biopolymers. Our aim was to identify natural aromatic compounds produced by white rot fungi of the genus Phlebia (Meruliaceae, Polyporales, Agaricomycetes), which comprises efficient decomposers of wood, wastes, and xenobiotics. Naturally produced aryl compounds were obtained by cultivating the fungi on a defined low-nitrogen liquid medium with glucose as carbon source. Culture supernatants were extracted and analyzed with UPLC-MS (ultra-performance liquid chromatography–mass spectrometry) and NMR (nuclear magnetic resonance). Enzyme assays, cultivation with 15N isotope–labeled nitrogen supplement, and aryl compound–feeding experiments were performed to assess biosynthesis mechanisms. Together with the well-known secondary metabolite veratryl alcohol and its enzymatic oxidation product veratraldehyde, we identified two nitroaryl derivatives, 6-nitroveratryl alcohol and 4-nitroveratrole, accumulating in culture supernatants of Phlebia spp. Cultivation of P. radiata isolate 2776 with NH4NO3 caused higher product yield of the nitroaryl compounds than 15NH4Cl supplementation, suggesting a role of nitrate ions in formation of nitroaryl products. With 15N-labeled supplementation, however, incorporation of nitrogen also from ammonium ions was observed. Although lignin peroxidase (LiP) enzyme activities correlated with appearance of nitroaryl compounds, their formation from veratryl alcohol by LiP was not accomplished in vitro in reaction mixtures with extracellular supernatants. In compound-feeding experiments, additional glycosylated derivative of 6-nitroveratryl alcohol was detected in P. radiata cultures, and nitroguaiacol was formed from nitroveratrole. These results indicate multiple pathways including both intra- and extracellular metabolism in biosynthesis and bioconversion of monoaromatic aryl compounds and their derivatives in fungi of Phlebia
Intercomparison exercise of easy-to-measure and non-volatile difficult-to-measure analysis in homogenised high activity steel
No full textIntercomparison exercises (IE) are a way for laboratories to test their analytical performance. In case of difficult-to-measure (DTM) radionuclide analysis, participation in IEs are important due to the lack of reference materials. This paper reports the results from an IE focusing on non-volatile DTM analysis in homogenised high activity steel. The IE was carried out according to the ISO 13528 standard, in which the performances are assessed using z score. The z scores were generally acceptable. The experimental results were compared with activation calculation results showing wide range of compatibility.</p
Measuring damage anisotropy in concrete from ultrasound velocity data
No full textThe uniaxial compression of an initially isotropic concrete specimen induces a damage pattern that is anisotropic: in the direction of loading, the concrete undergoes compaction, while in the directions orthogonal to the loading direction, concrete cracking can be observed. In order to quantify such damage patterns, one possibility is to observe the changes in the stiffness tensor of a compressed specimen with respect to the stiffness tensor of the corresponding virgin state specimen. The eigensolutions of the Kelvin–Christoffel matrix for anisotropic media provide the relation between ultrasound wave velocities in given wavefront and polarization directions and the stiffness matrix components. In this study, it is shown how using the through transmission method for the determination of first-time arrival, one can evaluate the sound wave velocities in different directions and compute the stiffness tensor components for a damaged concrete specimen. Plots of stiffness tensor components as a function of non-recoverable strain give a qualitative measure of the anisotropic strain degradation process
MITE: the Minimum Information about a Tailoring Enzyme database for capturing specialized metabolite biosynthesis
No full textSecondary or specialized metabolites show extraordinary structural diversity and potent biological activities relevant for clinical and industrial applications. The biosynthesis of these metabolites usually starts with the assembly of a core ‘scaffold’, which is subsequently modified by tailoring enzymes to define the molecule’s final structure and, in turn, its biological activity profile. Knowledge about reaction and substrate specificity of tailoring enzymes is essential for understanding and computationally predicting metabolite biosynthesis, but this information is usually scattered in the literature. Here, we present MITE, the Minimum Information about a Tailoring Enzyme database. MITE employs a comprehensive set of parameters to annotate tailoring enzymes, defining substrate and reaction specificity by the expressive reaction SMARTS (Simplified Molecular Input Line Entry System Arbitrary Target Specification) chemical pattern language. Both human and machine readable, MITE can be used as a knowledge base, for in silico biosynthesis, or to train machine-learning applications, and tightly integrates with existing resources. Designed as a community-driven and open resource, MITE employs a rolling release model of data curation and expert review. MITE is freely accessible at https://mite.bioinformatics.nl/
Some Problems in the Ethical Impact Assessment of Emerging Technologies and Socio-Technical Visions:Case CityVerse
No full textThis paper examines methodological challenges in the participatory ethical assessment of emerging technologies in urban contexts, using the CityVerse vision in Tampere, Finland as a case study. While metaverse technologies promise to transform smart cities by blending physical and virtual spaces, their ethical implications remain unclear. Through focus groups with city officials, we explored how participatory methods can effectively evaluate ethical dimensions of emerging technologies when they remain largely conceptual. Our findings reveal that while stakeholders can generate substantive ethical discourse, they struggle with the abstract nature of metaverse experiences, producing more questions than definitive answers. We argue that sociotechnical visions serve better as platforms for ethical discourse than as concrete implementation plans, functioning primarily to surface tacit values and assumptions. The study contributes to ethical technology assessment methodologies by suggesting that for emerging technologies, developing structured ontologies of questions may prove more valuable than premature answers. We conclude that CityVerse design should be approached as an ongoing discourse—not merely about technologies, but fundamentally about designing for improved quality of human life—where participatory ethical vision assessment functions as a form of collaborative conceptual engineering.</p
Flexible Cu2AgBiI6-based perovskite-inspired solar cells using large-scale processing methods
No full textIn this work, emerging perovskite-inspired Cu2AgBiI6 (CABI) solar cells were successfully fabricated on flexible substrates, demonstrating that the transition from rigid to flexible materials does not compromise device performance. This underscores the versatility of CABI on two different kinds of substrates. Additionally, to optimize charge extraction, we selected a polymeric hole-transport material (HTM), PPDT2FBT, whose energy levels align with CABI. The PPDT2FBT-based devices outperformed those using the well-known poly(3-hexylthiophene) (P3HT), leading to power conversion efficiencies as high as approximately 0.8%. These results suggest that PPDT2FBT may hold promise as a HTM for use in low-toxicity, perovskite-inspired photovoltaic systems, such as those based on CABI. Furthermore, roll-to-roll processing techniques, crucial for scalable production, were tested. However, controlling the morphology of the active layer remains a significant challenge. These findings represent critical steps toward the large-scale manufacturing and commercialization of flexible, PIM-based solar cells
Modeling Thermal Effects in Atomic Layer Deposition for Trench-Shaped Structures
No full textAn atomic layer deposition (ALD) simulation approach is presented for transient diffusion of heat and mass at low Knudsen numbers (Kn < 0.1), focusing on thermal effects in trench-shaped structures. Two boundary conditions (BCs) are analyzed: the ‘thin wall’ BC incorporates exothermic reactions with a derived wall heat flux term, and the ‘thick wall’ BC maintains constant wall temperature ranging between 500 K and 800 K. For both BCs, we examine aspect ratios from 1 to 100. The chosen BC significantly impacts reaction kinetics/peak temperatures, with local temperature variations up to 200 K under ‘thin wall’ conditions. The coating time ratio between ‘thin wall’ and ‘thick wall’ ranges from 0.9 to 1.7. Two ‘universal’ functional forms are proposed to explain how surface coverage depends on time and how coating time relates to aspect ratio and diffusion timescale. Results emphasize the crucial role of temperature distribution in ALD, impacting growth per cycle, reactant decomposition/desorption, and potential substrate damage
Oxide Formation at the Sulfide Film-Copper Interface in Anoxic Sulfide Solution and On-Line Sulfide Detection Via Linear Polarization Resistance
Get PDFThe observation of a thin oxide film on oxygen free phosphorous doped copper after several days of exposure in supposedly anoxic conditions poses several questions, where the most straight-forward answers regarding sample preparation and handling is oftentimes overlooked. In an effort to minimize the environmental factors contributing to the oxide formation on the copper surface, a flow through cell arrangement was built to investigate the oxide formation at the Cu–Cu2S interface after exposure to anoxic sulfide containing phosphate buffer solution. The post exposure characterization by scanning electron microscopy and focused ion beam revealed no oxide formation on the copper surface in the absence of oxygen, while the exposure of the copper surface during the metallographic sample preparation phase, which employs the use of aerated water, causes the formation of copper oxide. Furthermore, a novel technique for noninvasive, semi-quantitative, and on-line sulfide determination is presented. The anodic current density determined from the linear polarization resistance of copper in sulfide solution was found to linearly increase with sulfide concentration.</p
Incorporation of a pyrethroid-based insecticide system into regenerated cellulose:interfacial interactions and effect on fiber formation
No full textInsecticide treated nets (ITNs) are a key tool for controlling vector-borne diseases, such as malaria. However, they are traditionally made of non-renewable polymeric materials, which lack sustainability and longevity. The goal of this research is to address this issue by developing renewable, bio-based fibers that can carry insecticides while remaining suitable for netting fabric, using readily available and abundant cellulose as a raw material. To achieve this, understanding the underlying interactions between insecticides and cellulose is necessary, especially under the dissolution and regeneration conditions. Permethrin, a type of pyrethroid insecticide used in ITNs to kill malaria mosquitoes, is often mixed with piperonyl butoxide (PBO) to combat insecticide resistance. In this study, the adsorption of permethrin and PBO onto cellulose model surfaces treated with two potential direct dissolution solvents (deep eutectic solvent and ionic liquid), which yielded different allomorphs of cellulose, and was examined using surface-sensitive methods. The insecticides were then incorporated into the ionic liquid containing dissolved cellulose, processed into fiber via dry-jet wet spinning, and evaluated for mechanical performance and insecticide retention
Cascade synthesis of diarylamines catalyzed by oxygen-rich and porous carbon
No full textActivated carbon derived porous materials, effectively enriched with OH and C[double bond, length as m-dash]O groups, were found to mediate, in a cascade manner, the condensation between anilines and 3-hexenones or β-tetralones, followed by their aromatization to diarylamines. The reaction proceeds via in situ formation of enamine intermediates which are subsequently oxidatively dehydrogenated in presence of a molecular oxidant under inert atmosphere. The functional groups on the carbon surface contributed actively to the catalysis: phenolic hydroxyl groups were found to promote the coupling of amines and ketones to imines and their tautomerization to enamines, while the C[double bond, length as m-dash]O groups of the quinoidic moieties catalyze the dehydrogenative aromatization step. The carbon material's extensive porous structure turns out to be critical to preserve the reactive β,γ-unsaturated cyclohexanone derivatives and their enamine intermediates from undesirable coupling and condensation side-reactions. The carbocatalyst can be regenerated by molecular N-oxo quinoline, which acts as a more convenient and cleaner stoichiometric oxidant in comparison with standard aerobic conditions (oxygen-rich atmosphere). The developed methodology delivered up to 93% yields for many diarylamines, formerly accessible exclusively via Pd-mediated couplings. Computational DFT study of possible enamine reaction modes with quinone model compounds, combined with kinetic isotope effects (KIE) suggest that the aromatization reaction is triggered by hydride abstraction at the benzylic position of the enamine intermediate