| 1. |
- Burrascano, S., et al.
(författare)
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Where are we now with European forest multi-taxon biodiversity and where can we head to?
- 2023
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Ingår i: Biological Conservation. - 0006-3207. ; 284
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Tidskriftsartikel (refereegranskat)abstract
- The European biodiversity and forest strategies rely on forest sustainable management (SFM) to conserve forest biodiversity. However, current sustainability assessments hardly account for direct biodiversity indicators. We focused on forest multi-taxon biodiversity to: i) gather and map the existing information; ii) identify knowledge and research gaps; iii) discuss its research potential. We established a research network to fit data on species, standing trees, lying deadwood and sampling unit description from 34 local datasets across 3591 sampling units. A total of 8724 species were represented, with the share of common and rare species varying across taxonomic classes: some included many species with several rare ones (e.g., Insecta); others (e.g., Bryopsida) were repre-sented by few common species. Tree-related structural attributes were sampled in a subset of sampling units (2889; 2356; 2309 and 1388 respectively for diameter, height, deadwood and microhabitats). Overall, multi-taxon studies are biased towards mature forests and may underrepresent the species related to other develop-mental phases. European forest compositional categories were all represented, but beech forests were over-represented as compared to thermophilous and boreal forests. Most sampling units (94%) were referred to a habitat type of conservation concern. Existing information may support European conservation and SFM stra-tegies in: (i) methodological harmonization and coordinated monitoring; (ii) definition and testing of SFM in-dicators and thresholds; (iii) data-driven assessment of the effects of environmental and management drivers on multi-taxon forest biological and functional diversity, (iv) multi-scale forest monitoring integrating in-situ and remotely sensed information.
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| 2. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 3. |
- Endrődi, Balázs, 1987-, et al.
(författare)
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Electrochemical synthesis and characterization of poly(3-hexylthiophene)/single-walled carbon nanotube array hybrid materials
- 2016
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Ingår i: Journal of Solid State Electrochemistry. - : Springer. - 1432-8488 .- 1433-0768. ; 20:11, s. 3179-3187
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we demonstrate that by directly employing single-walled carbon nanotube arrays (SWCNT-arrays)-grown on conductive substrates-as working electrodes, selective and uniform electrodeposition of a conducting polymer, namely poly(3-hexylthiophene), can be achieved on the surface of the nanotubes. The overall kinetic pattern of the electrodeposition was studied by separating the deposition charge from the one related to the redox transformation of the polymer film deposited during the precedent cycles. Both the structure and the electrochemical properties of the hybrid materials were studied as a function of the electrodeposition cycles, thus the amount of the formed polymer. The hybrids were characterized by electron microscopic (SEM, TEM) and vibrational spectroscopic (Raman spectroscopy) means. The obtained results were compared and contrasted with those gathered on macroscopic-sized multi-walled carbon nanotube array-based composites in our group recently. Overall, we conclude that electrochemical polymerization is an attractive tool to synthesize conducting polymer/SWCNT hybrid materials with controlled composition and morphology.
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| 4. |
- Gondo, Thamani F., et al.
(författare)
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Pesticide residues in fruits and vegetables from the southern part of Botswana
- 2021
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Ingår i: Food Additives and Contaminants: Part B Surveillance. - : Informa UK Limited. - 1939-3210 .- 1939-3229. ; 14:4, s. 271-280
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Tidskriftsartikel (refereegranskat)abstract
- This study reports a surveillance of multi-pesticide residues of fruits and vegetables sold in the local markets carried out in 2018–2019 in Botswana to access consumer safety. A validated method for analysis of 232 pesticide residues in fruits and vegetables was applied, based on QuEChERS-GC-MS/MS methodology. A total of 83 fruit and vegetable sold in different markets were bought from three different areas of the southern region. Levels of pesticides ranged between 0.0032 ± 0.0009 mg/kg and 70.4 ± 19.4 mg/kg. A total of 78% of the samples contained pesticide residues, whereas only 13% of the samples violated the EU/Codex MRLs. In particular, rape vegetable samples exceeded legislative limits most, followed by cabbage, green pepper and tomato. The most frequently detected compounds were chlopyrifos, chlorfenapyr, tebuconazole, methamidophos and cypermethrin. These results will serve as a foundation for future studies, involving continuous monitoring programmes.
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| 5. |
- Mayer, Peter J., et al.
(författare)
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Structure–Property Relationships in Unsymmetric Bis(antiaromatics) : Who Wins the Battle between Pentalene and Benzocyclobutadiene?
- 2020
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Ingår i: Journal of Organic Chemistry. - : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 85:8, s. 5158-5172
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Tidskriftsartikel (refereegranskat)abstract
- According to the currently accepted structure-property relationships, aceno-pentalenes with an angular shape (fused to the 1,2-bond of the acene) exhibit higher antiaromaticity than those with a linear shape (fused to the 2,3-bond of the acene). To explore and expand the current view, we designed and synthesized molecules where two isomeric, yet, different, 8 pi antiaromatic subunits, a benzocyclobutadiene (BCB) and a pentalene, are combined into, respectively, an angular and a linear topology via an unsaturated six-membered ring. The antiaromatic character of the molecules is supported experimentally by H-1 NMR, UV-vis, and cyclic voltammetry measurements and X-ray crystallography. The experimental results are further confirmed by theoretical studies including the calculation of several aromaticity indices (NICS, ACID, HOMA, FLU, MCI). In the case of the angular molecule, double bond-localization within the connecting six-membered ring resulted in reduced antiaromaticity of both the BCB and pentalene subunits, while the linear structure provided a competitive situation for the two unequal [4n]pi subunits. We found that in the latter case the BCB unit alleviated its unfavorable antiaromaticity more efficiently, leaving the pentalene with strong antiaromaticity. Thus, a reversed structure-antiaromaticity relationship when compared to aceno-pentalenes was achieved.
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| 6. |
- Samu, G. F., et al.
(författare)
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Bandgap-engineered quaternary MxBi2-xTi2O7 (M: Fe, Mn) semiconductor nanoparticles : Solution combustion synthesis, characterization, and photocatalysis
- 2017
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Ingår i: Applied Catalysis B. - : Elsevier. - 0926-3373 .- 1873-3883. ; 208, s. 148-160
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Tidskriftsartikel (refereegranskat)abstract
- Ternary and quaternary metal oxides form a rapidly emerging class of new functional materials tackling the grand challenge of efficient solar energy harvesting. Currently the main interest is devoted to the characteristics of these materials and little consideration has been given to their preparation. Solution combustion synthesis (SCS) is considered a green and sustainable alternative to the widely employed energy-and/or time-consuming synthesis methods. In this study, SCS was employed to prepare Bi2Ti2O7 and to perform bandgap engineering through foreign ion (Fe, Mn) incorporation. The synthesized materials were characterized by powder X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray microanalysis, diffuse reflectance UV-vis and Raman spectroscopy, and surface area determination via N-2 adsorption. We found that nanocrystalline materials were formed during the SCS synthesis. Further, the phase composition of these materials and the amount of the foreign metal ions incorporated in the parent structure, could be effectively controlled. Consequently, the SCS technique provided a simple and reliable tool for bandgap engineering. The photocatalytic activity of the materials was tested through methyl orange degradation, and the intrinsic photocatalytic activity of the various samples were compared after deconvoluting the effect of their vastly different specific surface areas.
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| 7. |
- Tóth, P. S., et al.
(författare)
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Hyphenated in situ conductance and spectroelectrochemical studies of polyaniline films in strongly acidic solutions
- 2013
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Ingår i: Electrochimica Acta. - : Elsevier BV. - 0013-4686 .- 1873-3859. ; 110, s. 446-451
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Tidskriftsartikel (refereegranskat)abstract
- The redox transformations of polyaniline (PANI) have been studied in acidic solutions of pH <1 by in situ optical electrochemistry and in situ ac conductance technique applied both separately and by using them in a hyphenated mode. For the combination of the two in situ electrochemical techniques, thin layers have been deposited on a special double-band ITO electrode (dbITO), with a gap of 15 p,m. The structure of the dbITO printed circuit electrode made possible to monitor simultaneously the electrochemical, the optical and the conductance changes during the redox processes, occurring in the self-same film. Spectral features confirmed the existence of protonated segments in the reduced film, formed in these strongly acidic media, assumingly via the proton partition at the reduced film/solution interface, coupled also with anion uptake to fulfil electroneutrality. The simultaneous in situ spectral and ac conductance data gave evidence that the development of the conducting state starts only with the oxidative transformation of emeraldine type radical cations coupled with anion entry, leading to the increase in the quinoid/benzonoid ratio in the charge carriers.
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