Institution
Université Nantes Angers Le Mans
Education•Nantes, France•
About: Université Nantes Angers Le Mans is a education organization based out in Nantes, France. It is known for research contribution in the topics: Geology & Population. The organization has 434 authors who have published 249 publications receiving 7208 citations. The organization is also known as: PRES Universite Nantes Angers Le Mans.
Papers
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TL;DR: Saturation mutagenesis at this position demonstrated that valine and tryptophan further increased the transglycosylation performance of BgaB and GP643.3 (BgaB R109W) was shown to be the most efficient mutant.
Abstract: A mutagenesis approach was applied to the beta-galactosidase BgaB from Geobacillus stearothermophilus KVE39 in order to improve its enzymatic transglycosylation of lactose into oligosaccharides. A simple screening strategy, which was based on the reduction of the hydrolysis of a potential transglycosylation product (lactosucrose), provided mutant enzymes possessing improved synthetic properties for the autocondensation product from nitrophenyl-galactoside and galacto-oligosaccharides (GOS) from lactose. The effects of the mutations on enzyme activity and kinetics were determined. An change of one arginine to lysine (R109K) increased the oligosaccharide yield compared to that for the wild-type BgaB. Subsequently, saturation mutagenesis at this position demonstrated that valine and tryptophan further increased the transglycosylation performance of BgaB. During the transglycosylation reaction with lactose of the evolved beta-galactosidases, a major trisaccharide was formed. Its structure was characterized as beta-D-galactopyranosyl-(1-->3)-beta-D-galactopyranosyl-(1-->4)-D-glucopyranoside (3'-galactosyl-lactose). At the lactose concentration of 18% (wt/vol), this trisaccharide was obtained in yields of 11.5% (wt/wt) with GP21 (BgaB R109K), 21% with GP637.2 (BgaB R109V), and only 2% with the wild-type BgaB enzyme. GP643.3 (BgaB R109W) was shown to be the most efficient mutant, with a 3'-galactosyl-lactose production of 23%.
81 citations
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TL;DR: It is found that a larvicide spraying at regular time intervals acted as a preventive measure against mosquito emergence, and that such a strategy was more efficient than spraying only when the abundance of host-seeking females reached a given threshold.
81 citations
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TL;DR: In this article, a detailed review of the physics basis for the DTE2 operational scenarios, including the fusion power predictions through first principle and integrated modelling, and the impact of isotopes in the operation and physics of DTE plasmas (thermal and particle transport, high confinement mode, Be and W erosion, fuel recovery, etc).
Abstract: For the past several years, the JET scientific programme (Pamela et al 2007 Fusion Eng. Des.
82 590) has been engaged in a multi-campaign effort, including experiments in D, H and T,
leading up to 2020 and the first experiments with 50%/50% D–T mixtures since 1997 and the
first ever D–T plasmas with the ITER mix of plasma-facing component materials. For this
purpose, a concerted physics and technology programme was launched with a view to prepare
the D–T campaign (DTE2). This paper addresses the key elements developed by the JET
programme directly contributing to the D–T preparation. This intense preparation includes
the review of the physics basis for the D–T operational scenarios, including the fusion power
predictions through first principle and integrated modelling, and the impact of isotopes in the
operation and physics of D–T plasmas (thermal and particle transport, high confinement mode
(H-mode) access, Be and W erosion, fuel recovery, etc). This effort also requires improving
several aspects of plasma operation for DTE2, such as real time control schemes, heat load
control, disruption avoidance and a mitigation system (including the installation of a new
shattered pellet injector), novel ion cyclotron resonance heating schemes (such as the threeions
scheme), new diagnostics (neutron camera and spectrometer, active Alfven eigenmode
antennas, neutral gauges, radiation hard imaging systems…) and the calibration of the JET
neutron diagnostics at 14 MeV for accurate fusion power measurement. The active preparation
of JET for the 2020 D–T campaign provides an incomparable source of information and a
basis for the future D–T operation of ITER, and it is also foreseen that a large number of key
physics issues will be addressed in support of burning plasmas.
79 citations
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TL;DR: Toxin extracts obtained from collected biomass were purified using different techniques such as liquid-liquid partition or size exclusion, and open-column chromatography with Sephadex LH20 phase yielded the best results with a cleanup efficiency of 93% and recovery of about 85%, representing an increase of toxin percentage by 13 fold.
Abstract: Ostreopsis cf. ovata produces palytoxin analogues including ovatoxins (OVTXs) and a putative palytoxin (p-PLTX), which can accumulate in marine organisms and may possibly lead to food intoxication. However, purified ovatoxins are not widely available and their toxicities are still unknown. The aim of this study was to improve understanding of the ecophysiology of Ostreopsis cf. ovata and its toxin production as well as to optimize the purification process for ovatoxin. During Ostreopsis blooms in 2011 and 2012 in Villefranche-sur-Mer (France, NW Mediterranean Sea), microalgae epiphytic cells and marine organisms were collected and analyzed both by LC-MS/MS and hemolysis OPEN ACCESS Mar. Drugs 2014, 12 2852 assay. Results obtained with these two methods were comparable, suggesting ovatoxins have hemolytic properties. An average of 223 μg· kg −1 of palytoxin equivalent of whole flesh was found, thus exceeding the threshold of 30 μg· kg −1 in shellfish recommended by the European Food Safety Authority (EFSA). Ostreopsis cells showed the same toxin profile both in situ and in laboratory culture, with ovatoxin-a (OVTX-a) being the most abundant analogue (~50%), followed by OVTX-b (~15%), p-PLTX (12%), OVTX-d (8%), OVTX-c (5%) and OVTX-e (4%). Ostreopsis cf. ovata produced up to 2 g of biomass per L of culture, with a maximum concentration of 300 pg PLTX equivalent cell −1. Thus, an approximate amount of 10 mg of PLTX-group toxins may be produced with 10 L of this strain. Toxin extracts obtained from collected biomass were purified using different techniques such as liquid-liquid partition or size exclusion. Among these methods, open-column chromatography with Sephadex LH20 phase yielded the best results with a cleanup efficiency of 93% and recovery of about 85%, representing an increase of toxin percentage by 13 fold. Hence, this purification step should be incorporated into future isolation exercises.
78 citations
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TL;DR: In this article, the uplift capacity of helical anchors normally increases with the number of the helical plates and the rate of capacity gain is variable, considering that the disturbance caused by the anchor installatio...
Abstract: The uplift capacity of helical anchors normally increases with the number of helical plates. The rate of capacity gain is variable, considering that the disturbance caused by the anchor installatio...
76 citations
Authors
Showing all 446 results
Name | H-index | Papers | Citations |
---|---|---|---|
Jean-Pierre Benoit | 78 | 428 | 22384 |
Denis Jacquemin | 69 | 623 | 22712 |
Olivier Beauchet | 63 | 320 | 13778 |
Dominique Heymann | 62 | 347 | 13497 |
Paul Calès | 61 | 353 | 14123 |
Jérôme Guicheux | 58 | 238 | 9568 |
Ignacio Anegon | 57 | 265 | 11797 |
Cédric Annweiler | 54 | 346 | 9990 |
Michel Neunlist | 53 | 204 | 9136 |
Patrick Saulnier | 50 | 219 | 13125 |
Bruno Le Bizec | 50 | 295 | 9082 |
Alain Mercat | 49 | 142 | 16603 |
Vincent Rohmer | 48 | 121 | 7090 |
J.C. Bernède | 47 | 345 | 7669 |
Jean-Philippe Antignac | 46 | 171 | 6392 |