The Use of Near Infrared Reflectance Spectroscopy (NIRS) to Follow the Leaf/Stem Ratio of Legumes During Drying

Legume-rich mixed swards allow the production of a high quantity protein-rich forage with low nitrogen input. Nevertheless, during hay or silage making, dry matter losses as high as, 40 and 25 % have been recorded (Ciotti & Cavallero, 1979; Stilmant et al., 2004). These losses have mainly been linked to the high sensitivity to physical loss of legume leaves during drying. The development of a tool to characterise leaf losses or leaf/stem ratio during drying will help us to define the technical approach to reach the best compromise between quality loss reduction and good pre-wilting of legum-rich mixed swards. The aim of the present work was to test the potentialities of near infrared reflectance spectroscopy (NIRS) to quantify legume leaf/stem ratio in mixed grass-legume swards. The mixtures tested were perennial ryegrass-white clover (PR-WC), perennial ryegrass-red clover (PR-RC), timothy-red clover (T-RC) and cocksfoot-lucerne (C-L) swards. This technique has been successfully used to quantify leaf/stem ratio in pure perennial ryegrass swards (Leconte et al. 1999)

Effect of magnesium addition on the mechanical properties of metallic composite materials based on the eutectic Al-5.7% Ni alloy

The effect of Mg addns. on the mech. properties of dispersion hardening alloys, prepd. from the eutectic Al-5.7% Ni by casting and isostatic extrusion was detd. A small amt. of Mg increases significantly the tensile strength and fracture elongation, and esp. stabilizes the alloy structure for annealing at high tempinfo:eu-repo/semantics/publishe

Insectes tropicaux en collection au Musée de zoologie de l'université de Liège : une première approche

peer reviewedThe University of Liège Museum of Zoology holds some large and not well-known insect collections, which are still very well preserved, due to the work of famous entomologists and curators such as Fritz Carpentier and Noël Magis. Insects from tropical areas are very well presented in these collections and were collected all around the world. The expedition of Edouard van Beneden in Brazil (in company of two entomologists) provided numerous specimens, mainly Coleoptera. More than 8,500 insects were sent from Paraguay by the Estacion Entomologica ‘FABRE’ and are still preserved in the original mailing boxes. Due to investment of the University in cooperation projects with some African countries, numerous insects (mainly Lepidoptera and Coleoptera) were collected there between 1900 and 1990. The main source of exotic insect specimens is the “Léon Candèze’s collection of Lepidoptera from around the world”, which comprimes more than 9,500 specimens. A first inventory, which digitized all genera and families present in this collection, showed it contains at least five systematic types. However, the aforesaid collections need an in depth study from researchers interested in the genera and species they concern. Even though not every insect specimen is recorded in the handwritten registers or the collection database, the well- organised depositories allow finding them easy, and any request of study would be welcome

Macromolecular ligands for gadolinium MRI contrast agents

Macromolecular ligands for gadolinium contrast agents (CAs) were prepared via a “grafting to” strategy. Copolymers of oligoethylene glycol methyl ether acrylate (OEGA) and an activated ester monomer, pentafluorophenyl acrylate (PFPA), were synthesized and modified with the 1-(5-amino-3-aza-2-oxypentyl)-4,7,10-tris(tert-butoxycarbonylmethyl)-1,4,7,10-tetraazacyclododecane (DO3A-tBu-NH2) chelate for the complexation of Gd3+. The relaxivity properties of the ligated Gd3+ agents were then studied to evaluate the effect of macromolecular architecture on their behavior as magnetic resonance imaging (MRI) CAs. Ligands made from linear and hyperbranched macromolecules showed a substantially increased relaxivity in comparison to existing commercial Gd3+ MRI contrast agents. In contrast, star nanogel polymers exhibited a slightly lower relaxivity per Gd3+ ion (but still substantially higher relaxivity than existing low molecular weight commercial CAs). This work shows that macromolecular ligands have the potential to serve as components of Gd MRI agents as there are enhanced effects on relaxivity, allowing for lower Gd concentrations to achieve contrast, while potentially imparting control over pharmacokinetics

The Precise Molecular Location of Gadolinium Atoms has a Significant Influence on the Efficacy of Nanoparticulate MRI Positive Contrast Agents

In this work, we studied the influence of the structure of macromolecular ligands on the relaxivity of gadolinium contrast agents constructed as nanoparticle systems. Macromolecular ligands were assembled as single-molecule nanoparticles in the form of either discrete core cross-linked star polymers or hyperbranched polymers. 1-(5-Amino-3-aza-2-oxypentyl)-4,7,10-tris(tert-butoxycarbonylmethyl)-1,4,7,10-tetraaza-cyclododecane (DO3A–tBu–NH2) chelate was incorporated into different parts (arms, cores, and end-groups) of the polymeric structures using activated ester/amine nucleophilic substitutions, deprotected and complexed with Gd3+. The relaxivity properties of the ligated Gd3+ agents were then studied to evaluate the effect of macromolecular architecture and Gd3+ placement on their behavior as discrete nanoparticle magnetic resonance imaging (MRI) contrast agents. The precise placement of Gd3+ in the polymeric structures (and therefore in the nanoparticles) proved to be critical in optimizing the performance of the nanoparticles as MRI contrast agents. The relaxivity was measured to vary from 11 to 22 mM−1 s−1, 2–5 times higher than that of a commercial DOTA–Gd contrast agent when using a magnetic field strength of 0.47 T. The relaxivity of these nanoparticles was examined at different magnetic fields from 0.47 T to 9.4 T. Finally, the residence time of the coordinated water (τM) and the rotational correlation time of the final molecule (τR) were evaluated for these different nanostructures and correlated with the polymeric architecture

Multimetallic complexes and functionalized gold nanoparticles based on a combination of d- and f-elements

The new DO3A-derived dithiocarbamate ligand, DO3A-tBu-CS2K, is formed by treatment of the ammonium salt [DO3A-tBu]HBr with K2CO3 and carbon disulfide. DO3A-tBu-CS2K reacts with the ruthenium complexes cis-[RuCl2(dppm)2] and [Ru(CH═CHC6H4Me-4)Cl(CO)(BTD)(PPh3)2] (BTD = 2,1,3-benzothiadiazole) to yield [Ru(S2C-DO3A-tBu)(dppm)2]+ and [Ru(CH═CHC6H4Me-4)(S2C-DO3A-tBu)(CO)(PPh3)2], respectively. Similarly, the group 10 metal complexes [Pd(C,N-C6H4CH2NMe2)Cl]2 and [PtCl2(PPh3)2] form the dithiocarbamate compounds, [Pd(C,N-C6H4CH2NMe2)(S2C-DO3A-tBu)] and [Pt(S2C-DO3A-tBu)(PPh3)2]+, under the same conditions. The linear gold complexes [Au(S2C-DO3A-tBu)(PR3)] are formed by reaction of [AuCl(PR3)] (R = Ph, Cy) with DO3A-tBu-CS2K. However, on reaction with [AuCl(tht)] (tht = tetrahydrothiophene), the homoleptic digold complex [Au(S2C-DO3A-tBu)]2 is formed. Further homoleptic examples, [M(S2C-DO3A-tBu)2] (M = Ni, Cu) and [Co(S2C-DO3A-tBu)3], are formed from treatment of NiCl2·6H2O, Cu(OAc)2, or Co(OAc)2, respectively, with DO3A-tBu-CS2K. The molecular structure of [Ni(S2C-DO3A-tBu)2] was determined crystallographically. The tert-butyl ester protecting groups of [M(S2C-DO3A-tBu)2] (M = Ni, Cu) and [Co(S2C-DO3A-tBu)3] are cleaved by trifluoroacetic acid to afford the carboxylic acid products, [M(S2C-DO3A)2] (M = Ni, Cu) and [Co(S2C-DO3A)3]. Complexation with Gd(III) salts yields trimetallic [M(S2C-DO3A-Gd)2] (M = Ni, Cu) and tetrametallic [Co(S2C-DO3A-Gd)3], with r1 values of 11.5 (Co) and 11.0 (Cu) mM–1 s–1 per Gd center. DO3A-tBu-CS2K can also be used to prepare gold nanoparticles, Au@S2C-DO3A-tBu, by displacement of the surface units from citrate-stabilized nanoparticles. This material can be transformed into the carboxylic acid derivative Au@S2C-DO3A by treatment with trifluoroacetic acid. Complexation with Gd(OTf)3 or GdCl3 affords Au@S2C-DO3A-Gd with an r1 value of 4.7 mM–1 s–1 per chelate and 1500 mM–1 s–1 per object