Solvent evaporation driven entrapment of magnetic nanoparticles in mesoporous frame for designing a highly efficient MRI contrast probe

The present work reports a novel strategy of assembling maghemite (?-Fe2O3) nanoparticles (NPs) in mesoporous silica host for developing a highly efficient MRI contrast probe. Shrinkage of hydrophobic environment due to the continuous evaporation of chloroform from Chloroform-in-Water emulsions pushes the hydrophobic ?-Fe2O3 NPs towards the hydrophobic pores of silica spheres resulting in a water soluble dense assembly structure. Mesoporous silica only with straight pores is found to be suitable for this particular entrapment process, while with curved and twisted pores, NPs are found to be seated on the surface only. So-developed assembly system has retained the superparamagnetic behaviour of its comprising NPs and exhibited high colloidal stability and biocompatibility. A significant enhancement in MRI transverse relaxivity to 386.2?mM?1?s?1 from 191.8?mM?1?s?1 of isolated primary ?-Fe2O3 NPs, has been obtained due to the strong magnetic field generated by the large number of NPs packed in the porous channels and consequent faster relaxation process. The fabrication strategy can be extended for the development of designed secondary nanostructures with new magnetic effects and physical properties

Investigation of carbohydrate metabolism and transport in castor bean seedlings by cyclicjcross polarization imaging and spectroscopy

NMR experiments using13C-labeled compounds offer the possibility of noninvasive monitoring of carbohydrate transport and metabolism in living plants, but are usually hampered by the low sensitivity of the13C nucleus. The problem of low sensitivity can be overcome by using the cyclicJcross polarization (CYCLCROP) technique, which allows the indirect detection of13C nuclei coupled to1H nuclei with the high NMR sensitivity of protons. We report here on methods for imaging and spectroscopy based on the CYCLCROP technique, and their use in the firstin vivoNMR study of carbohydrate transport and metabolism in castor bean seedlings (Ricinus communis L.). Comprehensive acquisition strategies for the various NMR methods are given, including the procedure for setting up the experiments. In addition, a full analysis of the effect of relaxation on the signals generated from smallJ-coupled spin systems by the CYCLCROP sequence is given, and the high sensitivity of the sequence is demonstrated. In thein vivostudy of six-day-old castor bean seedlings, we were able to measure the uptake of labeled hexoses, supplied in solution to the cotyledons, and their conversion to sucrose, as well as the transport of this sucrose in the vascular bundles. Images of the actual distribution of labeled sucrose in the hypocotyl of the seedling have also been obtained. The resulting data show some evidence for a preferential incorporation of labeled fructose in the process of sucrose synthesis, which decreases with the time of incubation

Training Schrödinger's cat: Quantum optimal control: Strategic report on current status, visions and goals for research in Europe

It is control that turns scientific knowledge into useful technology: in physics and engineering it provides a systematic way for driving a dynamical system from a given initial state into a desired target state with minimized expenditure of energy and resources. As one of the cornerstones for enabling quantum technologies, optimal quantum control keeps evolving and expanding into areas as diverse as quantum-enhanced sensing, manipulation of single spins, photons, or atoms, optical spectroscopy, photochemistry, magnetic resonance (spectroscopy as well as medical imaging), quantum information processing and quantum simulation. In this communication, state-of-the-art quantum control techniques are reviewed and put into perspective by a consortium of experts in optimal control theory and applications to spectroscopy, imaging, as well as quantum dynamics of closed and open systems. We address key challenges and sketch a roadmap for future developments

NMR imaging of air spaces and metabolites in fruit and vegetables

This chapter deals with the principles and the applications of magnetic resonance imaging (MRI) for assessment of the distribution and of the amount of intercellular gas-filled spaces and major metabolites in fruit and vegetable tissues. Combining this information with measurements of water characteristics could enable the use of MRI in an integrative approach to plant characterization. In MRI, the presence of gas-filled intercellular spaces in plant tissues impacts the NMR relaxation behavior of water molecules because gas and water have different magnetic susceptibilities. This phenomenon can be exploited for the noninvasive detection of certain physiological disorders in fruit and vegetable tissues or for quantification of the spatial distribution of apparent microporosity. On the other hand, the amount and the distribution of major metabolites (sugars, starch, lipids, etc.) can be accessed by MRI using approaches based on differences in relaxation times or on chemical shift between water and metabolites protons. Here we provide an overview of the theoretical aspects of MRI methods and a description of different approaches. The imaging protocols for specific applications for both air space and metabolite imaging are discussed with respect to their application to fruits and vegetables.</p