General-base catalysed hydrolysis and nucleophilic substitution of activated amides in aqueous solutions

The reactivity of 1-benzoyl-3-phenyl-1,2,4-triazole (1a) was studied in the presence of a range of weak bases in aqueous solution. A change in mechanism is observed from general-base catalysed hydrolysis to nucleophilic substitution and general-base catalysed nucleophilic substitution. A slight tendency is also observed for the more hydrophobic general bases to show higher reactivity towards 1a. Aspartame is an effective nucleophile, possibly because nucleophilic substitution is subject to intramolecular general-base catalysis. A general conclusion derived from the present results is that unexpected rate effects can only be rationalised provided that the detailed reaction mechanisms are well understood. Copyright (C) 2003 John Wiley Sons, Ltd.</p

Naar een sterke grondstofketen voor verwerkte groenten

Dit rapport omvat een vergelijking van de bestaande en de gewenste situatie voor de grondstofvoorziening voor verwerkte groenten. Daarbij worden vooral de mogelijkheden voor beperking van de ketenkosten en voor versterking van de ketenstructuur in kaart gebracht. Het onderzoek laat zien welke voordelen zijn te behalen door verbeteringen in perceelsgrootte, gebiedskeuze, oogstorganisatie, afstemming tussen ketenpartijen en herstructurering van de grondstofketen. De uitkomsten zijn gebaseerd op analyses en berekeningen voor doperwten, sperziebonen, spinazie en waspee

A water-soluble tetraazaperopyrene dye as strong G-quadruplex DNA binder

The interactions of the water-soluble tetraazaperopyrene dye 1 with ct-DNA, duplex-[(dAdT)12⋅(dAdT)12], duplex-[(dGdC)12⋅(dGdC)12] as well as with two G-quadruplex-forming sequences, namely the human telomeric 22AG and the promotor sequence c-myc, were investigated by means of UV/visible and fluorescence spectroscopy, isothermal titration calorimetry (ITC) and molecular docking studies. Dye 1 exhibits a high affinity for G-quadruplex structures over duplex DNA structures. Furthermore, the ligand shows promising G-quadruplex discrimination, with an affinity towards c-myc of 2×107 m−1 (i.e., Kd=50 nm), which is higher than for 22AG (4×106 m−1). The ITC data reveal that compound 1 interacts with c-myc in a stoichiometric ratio of 1:1 but also indicate the presence of two identical lower affinity secondary binding sites per quadruplex. In 22AG, there are two high affinity binding sites per quadruplex, that is, one on each side, with a further four weaker binding sites. For both quadruplex structures, the high affinity interactions between compound 1 and the quadruplex-forming nucleic acid structures are weakly endothermic. Molecular docking studies suggest an end-stacking binding mode for compound 1 interacting with quadruplex structures, and a higher affinity for the parallel conformation of c-myc than for the mixed-hybrid conformation of 22AG. In addition, docking studies also suggest that the reduced affinity for duplex DNA structures is due to the non-viability of an intercalative binding mode

Transplantation of human pulpal and gingival fibroblasts attached to synthetic scaffolds

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72582/1/j.0909-8836.1999.eos107408.x.pd

Gewasbescherming en de balans van milieu en economie : Berekeningen bij de 2e Nota Duurzame gewasbescherming

Ministerie van Economische ZakenLandbouw en Innovati

Investigation of the interactions between methylene blue and intramolecular G-quadruplexes: an explicit distinction in electrochemical behavior

G-quadruplex sequences exist in eukaryotic organisms and prokaryotes, and the investigation of interactions between G-quadruplexes and small molecule ligands is important for gene therapy, biosensor fabrication, fluorescence imaging and so on. Here, we investigated the behaviour of methylene blue (MB), an electroactive molecule, in the presence of different intramolecular G-quadruplexes by electrochemical method using a miniaturized electrochemical device based on its intrinsic electrochemical property. Although the effects of MB on different intramolecular G-quadruplex structures are not obvious by circular dichroism spectroscopy, distinct differences in binding affinities of MB with different intramolecular G-quadruplexes were fast and easily observed by the electrochemical technique. At the same time, for the human telomerase G-rich sequence (HT), the diffusion current of MB changed sensitively under different ion conditions due to the formation of different conformations of HT, which indicated that our electrochemical method has the potential to study the influence of metal ions on the conformations of the G-quadruplexes with simplicity, rapid response and low cost. From all these, new stacking mechanism and rule were obtained, which were also validated by docking studies and isothermal titration calorimetry (ITC)

Energiezuinige teeltplanning voor de potplanten : een systeemontwerp

Het gaat in dit project om te onderzoeken wat er voor nodig is om in de potplantenteelt het planmatig telen te kunnen combineren met energiebesparing, om zo de energie-efficiëntie van het teeltproces te kunnen verhogen. Op grond van eerdere ervaring en vanwege de complexe wisselwerking van de klimaatregeling met weer, kasklimaat en de gewasfysiologie werd vooraf verondersteld dat hiervoor een model-ondersteund adviessysteem voor nodig is. Wil de ontwikkeling van een dergelijk systeem kans van slagen hebben dan zal het goed moeten aansluiten bij de informatiebehoefte van de telers

A focus on computer vision for non-contact monitoring of catalyst degradation and product formation kinetics

Chemists know the value of looking at a reaction for clues about reaction progress and success, but what-it-looks-like has never been quantified. Reid and co-workers (C. Yan, M. Cowie, C. Howcutt, K. M. P. Wheelhouse, N. S. Hodnett, M. Kollie, M. Gildea, M. H. Goodfellow and M. Reid, Chem. Sci., 2023, 14, 5323–5331, https://doi.org/10.1039/d2sc05702f) have developed an approach that uses camera footage of reactions to obtain quantitative descriptors of changes in reaction mixtures to support kinetic analysis