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•Laccases from T. pubescens were produced by semi solid-state fermentation.•Laccase was successfully immobilized by cross-linking plus entrapment.•Cross-linking prior to entrapment ...diminished laccase leakage from the beads.•Immobilized laccase removed almost completely 20 mg L−1 BPA in 2 h.•BPA (20 mg L−1) was efficiently removed in 10 successive batches.
The immobilization of crude laccase from Trametes pubescens by glutaraldehyde crosslinking prior to entrapment into Ca-alginate beads increased the immobilization yield by 30% and reduced the leaking by 7-fold compared to the immobilization with no crosslinking. The performance of the newly developed biocatalyst to degrade Bisphenol A (BPA) from aqueous solutions was tested. Thus, operating at optimal conditions (i.e. pH 5, 30 °C, 20 mg L−1 BPA and 1500 U L−1 laccase), a BPA removal higher than 99% in 2 h was achieved. This value is higher than those reported to date for BPA removal by immobilized laccases. In addition, the biocatalyst was able to remove BPA in 10 successive batches with an efficiency higher than 70% at the end of the last batch. BPA adsorption on the alginate beads was negligible, therefore BPA removal was only due to laccase action. Moreover, Fourier-transform Infrared (FTIR) spectroscopy suggested BPA transformation by laccase.
In this article, the novel approach to equations of motion for serial manipulators developed in literature by Bertrand and Bruneau (2013) is extended to make it usable for manipulators with general ...joints (i.e., prismatic and/or rotational). In this method, the dynamic model is explicitly and directly obtained from the structural parameters of the manipulator and matrix algebra without intermediate heavy calculations such as energy derivation. The correctness and efficiency of the described method are demonstrated through simulation of the dynamical equations of a 5-DOF SCARA robot. The simulation results obtained using the new formulation were compared with those derived by Kane’s method, Lagrange–Euler formulation, and GIM (generalized inertia matrix)-Christoffel’s algorithm, which proves the efficiency and correctness of the presented model. It was concluded that the new formulation requires less CPU time to generate explicit closed-form inverse dynamics. Finally, to illustrate the power of the new formulation in real-time control, a trajectory tracking control for the SCARA manipulator based on the numeric and symbolic computation of the inverse dynamic is established, and it is shown that the numeric and symbolic approaches based on our method are equivalent. As a consequence, the applicability of the new formulation in real-time model-based control is proved.
Our study aimed to determine the effect on barley (Hordeum vulgare L.) of adding potassium polyacrylate to a sandy soil under normal watering condition and drought. We focused on morphological and ...physiological characteristics of barley and its rhizosphere bacterial community structure using Illumina Miseq sequencing. It was found that under normal watering condition (70% of soil water holding capacity (WHC)), the soil water retention increased with the SAP addition to the soil. Barley plant height and weight, leaf relative water content and protein content decreased under drought (35% of soil WHC), the addition of SAP eliminated the negative effect of drought on plants, the proline content was reduced from 2.71 μg g
−1
leave dry weight with stressed plants to 0.99 μg g
−1
with only 0.2% of SAP. The barley rhizophere bacterial community was affected by drought. Changes in relative abundance were noticed at both phyla and OTU level. The SAP addition (0.8%) shifted the barley rhizophere bacterial community to become in part more similar to that of the normal watering condition. Also, we found that the SAP addition had a side effect itself on the barley rhizosphere bacterial community other than its capacity of water holding.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In this paper, we propose a stochastic model to describe over time the evolution of stress in a bolted mechanical structure depending on different thicknesses of a joint elastic piece. First, the ...studied structure and the experiment numerical simulation are presented. Next, we validate statistically our proposed stochastic model, and we use the maximum likelihood estimation method based on Euler–Maruyama scheme to estimate the parameters of this model. Thereafter, we use the estimated model to compare the stresses, the peak times, and extinction times for different thicknesses of the elastic piece. Some numerical simulations are carried out to illustrate different results.
La présente étude porte sur la nature des rhizobia associés aux légumineuses du genre Hippocrepis qui compte une dizaine d’espèces en Algérie et pour laquelle très peu de travaux ont été jusqu’ici ...consacrés. Les résultats de nos investigations qui ont portés sur 26 plants représentant 8 espèces de ce genre et provenant de 17 localités du nord et du sud du pays révèlent que tous les plants étaient nodulés et fixateurs d’azote, ce qui indique que les 8 espèces identifiées sont capables d’établir une symbiose efficiente avec les rhizobia présents dans les sols qui les supportent. Le séquençage du gène de l’ARN 16S des 26 souches de rhizobia isolées et authentifiées par des tests de nodulation au laboratoire permet de les assigner à 16 espèces de rhizobia réparties sur 5 genres: Ensifer, Mesorhizobium, Bradyrhizobium, Rhizobium et Neorhizobium avec une prédominance des représentants des genres Ensifer et Mesorhizobium. Les résultats de cette étude qui est la première dédiée spécifiquement au genre Hippocrepis indiquent que la symbiose à rhizobia et la capacité d’utiliser, par ce biais, l’azote atmosphérique sont communes chez les représentants de ce genre en Algérie, ils révèlent aussi la grande diversité des rhizobia qui sont associés à ce genre.
Celotno besedilo
Dostopno za:
BF, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Purpose Creating active learning opportunities requires building a learning culture in which the instructor plays the role of a facilitator, leaving the ultimate responsibility of learning to the ...student. The question, however, is whether this is happening in practice. This study aims to answer this question through instructors' perceptions of active learning in a higher education institution in Oman. Design/methodology/approach The study participants were 85 instructors working for a private university in Oman. Data were collected by surveying these instructors' perceptions of active learning practice indicators, such as active teaching strategies and student educational practices. This was followed by interviewing a random sample of the same instructors ( N = 10) to obtain a deeper understanding of their implementation of the active learning approach. Findings Data collected through the survey revealed that the shift from passive to active learning in higher education in Oman created a discrepancy between instructors' willingness to practice active learning and learners' unpreparedness to become autonomous learners. The follow-up interview findings confirmed this point, revealing instructors' negative perceptions of student participation and engagement in out-of-class activities. Originality/value This study is among the first to investigate the application of active learning in a higher education institution in Oman from the perspective of instructors.
La presente etude porte sur la nature des rhizobia associes aux legumineuses du genre Hippocrepis qui compte une dizaine d'especes en Algerie et pour laquelle tres peu de travaux ont ete jusqu'ici ...consacres. Les resultats de nos investigations qui ont portes sur 26 plants representant 8 especes de ce genre et provenant de 17 localites du nord et du sud du pays revelent que tous les plants etaient nodules et fixateurs d'azote, ce qui indique que les 8 especes identifiees sont capables d'etablir une symbiose efficiente avec les rhizobia presents dans les sols qui les supportent. Le sequencage du gene del'ARN 16S des 26 souches de rhizobia isolees et authentifiees par des tests de nodulation au laboratoire permet de les assigner a 16 especes de rhizobia reparties sur 5 genres: Ensifer, Mesorhizobium, Bradyrhizobium, Rhizobium et Neorhizobium avec une predominance des representants des genres Ensifer et Mesorhizobium. Les resultats de cette etude qui est la premiere dediee specifiquement au genre Hippocrepis indiquent que la symbiose a rhizobia et la capacite d'utiliser, par ce biais, l'azote atmospherique sont communes chez les representants de ce genre en Algerie, ils revelent aussi la grande diversite des rhizobia qui sont associes a ce genre. Mots-cles : diversite, rhizobia, Hippocrepis, Algerie, symbiose, nodulation. The present study focuses on the nature of the rhizobia associated with legumes of the genus Hippocrepis, which totals about 10 species in Algeria and for which very little work has been performed so far. The results of our investigations, which focused on 26 plants representing 8 species of this genus and coming from 17 localities in the north and south of the country, show that all plants were nodulated and nitrogen-fixing, which indicates that the species identified can establish an efficient symbiosis with the rhizobia present in the soils that support them. The sequencing of the 16S RNA gene of the 26 strains of rhizobia isolated and authenticated by nodulation tests in the laboratory allows their assignation to 16 species of rhizobia spread over 5 genera: Ensifer, Mesorhizobium, Bradyrhizobium, Rhizobium, and Neorhizobium with a predominance of representatives of the genera Ensifer and Mesorhizobium. The results of this study, which is the first dedicated to the genus Hippocrepis, show that the rhizobial symbiosis and its ability to use atmospheric nitrogen are common among representatives of the genus Hippocrepis in Algeria and reveal a great diversity of associated rhizobia. Journal Translation Keywords: diversity, rhizobia, Hippocrepis, Algeria, symbiosis, nodulation.
Celotno besedilo
Dostopno za:
BF, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Describing and conserving ecological interactions woven into ecosystems is one of the great challenges of the 21
century. Here, we present a unique dataset compiling the biotic interactions between ...two ecologically and economically important taxa: ground beetles (Coleoptera: Carabidae) and fungi. The resulting dataset contains the carabid-fungus associations collected from 392 scientific publications, 129 countries, mostly from the Palearctic region, published over a period of 200 years. With an updated taxonomy to match the currently accepted nomenclature, 3,378 unique associations among 5,564 records were identified between 1,776 carabid and 676 fungal taxa. Ectoparasitic Laboulbeniales were the most frequent fungal group associated with carabids, especially with Trechinae. The proportion of entomopathogens was low. Three different formats of the data have been provided along with an interactive data digest platform for analytical purposes. Our database summarizes the current knowledge on biotic interactions between insects and fungi, while offering a valuable resource to test large-scale hypotheses on those interactions.
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