EnCOrE (Encyclopédie de Chimie Organique Electronique): an Original Way to Represent and Transfer Knowledge from Freshmen to Researchers in Organic Chemistry

peer reviewedEnCOrE is an original proposal which is expected to allow to share and transfer knowledge in organic chemistry. The system will use MIDES a software, with a peer-to-peer architecture, which will allow to set up a technological and methodological frame to allow collaborative building of knowledge in between chemists. Learning GRID's services will help for Experimental electronic laboratory "LabCOrE" as well as for predictive computational tools

Investigating FAM-N pulses for signal enhancement in MQMAS NMR of quadrupolar nuclei

The authors would like to thank EPSRC (EP/K503162/1) for the award of a studentship to HFC and the ERC (EU FP7 Consolidator Grant 614290 “EXONMR”) for support. SEA would also like to thank the Royal Society and Wolfson Foundation for a merit award. The UK 850 MHz solid-state NMR Facility used in this research was funded by EPSRC and BBSRC (contract reference PR140003), as well as the University of Warwick including via part funding through Birmingham Science City Advanced Materials Projects 1 and 2 supported by Advantage West Midlands (AWM) and the European Regional Development Fund (ERDF). Financial support from the TGIR-RMN-THC Fr3050 CNRS to access the 800 MHz spectrometer (Lille) is gratefully acknowledged.Although a popular choice for obtaining high-resolution solid-state NMR spectra of quadrupolar nuclei, the inherently low sensitivity of the multiple-quantum magic-angle spinning (MQMAS) experiment has limited its application for nuclei with low receptivity or when the available sample volume is limited. A number of methods have been introduced in the literature to attempt to address this problem. Recently, we have introduced an alternative, automated approach, based on numerical simulations, for generating amplitude-modulated pulses (termed FAM-N pulses) to enhance the efficiency of the triple- to single-quantum conversion step within MQMAS. This results in efficient pulses that can be used without experimental reoptimisation, ensuring that this method is particularly suitable for challenging nuclei and systems. In this work, we investigate the applicability of FAM-N pulses to a wider variety of systems, and their robustness under more challenging experimental conditions. These include experiments performed under fast MAS, nuclei with higher spin quantum numbers, samples with multiple distinct sites, low-γ nuclei and nuclei subject to large quadrupolar interactions.Publisher PDFPeer reviewe

L’évaluation entre pairs dans des travaux de groupes : Impacts sur la motivation et sur la perception des étudiants

La faculté de Gembloux Agro Bio Tech qui forme principalement des bioingénieurs propose à ses étudiants de première année un nouveau cours intitulé « Question d’actualité en environnement ; projet ». Ce cours qui se veut avant tout être un cours d’intéressement se construit autour du questionnement des étudiants sur une thématique fixée, par le prisme de leurs matières enseignées en première année. Habitués aux cours ex-cathedra organisés dans de grands amphithéâtres, les 300 étudiants de première année se retrouvent répartis en groupes de 6 étudiants et doivent réaliser les travaux associés à ce cours en utilisant deux outils de collaboration asynchrones à savoir Diigo et un wiki. La construction de ce cours leur laisse une grande liberté d’organisation. Seules 8h de présentiel sont placées à l’horaire. Les étudiants doivent donc s’organiser entre eux pour soumettre dans les délais imposés deux travaux qu’ils devront réaliser collaborativement et en ligne. L’évaluation de ce cours n’est pas associée à un examen traditionnel. La note finale est construite sur base des deux travaux rendus par les étudiants plus un travail individuel de réflexion sur l’expérience de travail de groupe. Pour chacun des travaux rendus, les étudiants bénéficient de la même note collective reflétant la qualité du travail soumis plus une note individuelle qui reflète quant à elle la participation de l’étudiant dans le travail de groupe. Si lors de la première année cette participation individuelle était sanctionnée par l’enseignant qui avait accompagné le groupe, nous avons cette année, donné la responsabilité à l’étudiant d’évaluer la participation de ses pairs. Cette communication analysera l’impact de ce style de notation sur la motivation et la perception du cours par les étudiants

Investigating sensitivity improvement methods for quadrupolar nuclei in solid-state nuclear magnetic resonance

The study of quadrupolar nuclei using NMR spectroscopy in the solid state significantly increased in popularity from the end of the 20th century, with the introduction of specific methods to acquire spectra free from the effects of the quadrupolar interaction, that results in broadened lineshapes that cannot be completely removed by spinning the sample at the magic angle (MAS), unlike most of the other interactions present in the solid state. The first technique which allows, without any specific hardware, the removal of this broadening has been the Multiple-Quantum MQMAS experiment. The method quickly gained a popularity within the NMR community, with numerous successful applications published. However, the multiple-quantum filtration step in this experiment relies on severely limits sensitivity, restricting application to the most sensitive nuclei. Extending the applicability of MQMAS to less receptive nuclei requires the use of signal improvement techniques. There are multiple examples of such approaches in the literature, but most of these require additional optimisation that may be time-consuming, or simply impossible, on less receptive nuclei. This work introduces a novel signal improvement technique for MQMAS, called FAM-N. Its optimisation is solely based on density matrix simulations using SIMPSON, implying no additional experimental optimisation is required, while improving the signal in MQMAS spectra by equivalent or higher amounts than other common methods. In order to prove the applicability of this method on virtually any system, FAM-N has been investigated by simulation, and tested experimentally using a number of model samples, as well as samples known to be challenging to study by NMR. This work also explores other aspects of NMR spectroscopy on quadrupolar nuclei. Adiabatic inversion of the satellite populations can be performed to improve the central transition signal in static or MAS spectra. A range of methods has been tested and compared, with particular attention given to hyperbolic secant-shaped pulses, for which its performance have been described. Finally, cross-polarisation from a spin I = 1/2 nucleus to a quadrupolar nucleus has been investigated. After reviewing the theory for the static case, simulations have been performed under MAS in order to identify the conditions for efficient magnetisation transfer, with applications in spectral editing or for the combination with MQMAS