Liquid-state NMR analysis of nanocelluloses

Recent developments in ionic liquid electrolytes for cellulose or biomass dissolution has also allowed for high-resolution 1H and 13C NMR on very high molecular weight cellulose. This permits the development of advanced liquid-state quantitative NMR methods for characterization of unsubstituted and low degree of substitution celluloses, for example, surface-modified nanocelluloses, which are insoluble in all molecular solvents. As such, we present the use of the tetrabutylphosphonium acetate ([P4444][OAc]):DMSO-d6 electrolyte in the 1D and 2D NMR characterization of poly(methyl methacrylate) (PMMA)-grafted cellulose nanocrystals (CNCs). PMMA-g-CNCs was chosen as a difficult model to study, to illustrate the potential of the technique. The chemical shift range of [P4444][OAc] is completely upfield of the cellulose backbone signals, avoiding signal overlap. In addition, application of diffusion-editing for 1H and HSQC was shown to be effective in the discrimination between PMMA polymer graft resonances and those from low molecular weight components arising from the solvent system. The bulk ratio of methyl methacrylate monomer to anhydroglucose unit was determined using a combination of HSQC and quantitative 13C NMR. After detachment and recovery of the PMMA grafts, through methanolysis, DOSY NMR was used to determine the average self-diffusion coefficient and, hence, molecular weight of the grafts compared to self-diffusion coefficients for PMMA GPC standards. This finally led to a calculation of both graft length and graft density using liquid-state NMR techniques. In addition, it was possible to discriminate between triads and tetrads, associated with PMMA tacticity, of the PMMA still attached to the CNCs (before methanolysis). CNC reducing end and sulfate half ester resonances, from sulfuric acid hydrolysis, were also assignable. Furthermore, other biopolymers, such as hemicelluloses and proteins (silk and wool), were found to be soluble in the electrolyte media, allowing for wider application of this method beyond just cellulose analytics.Peer reviewe

Effects of dexmedetomidine, propofol, sevoflurane and S-ketamine on the human metabolome A randomised trial using nuclear magnetic resonance spectroscopy

BACKGROUND Pharmacometabolomics uses large-scale data capturing methods to uncover drug-induced shifts in the metabolic profile. The specific effects of anaesthetics on the human metabolome are largely unknown. OBJECTIVE We aimed to discover whether exposure to routinely used anaesthetics have an acute effect on the human metabolic profile. DESIGN Randomised, open-label, controlled, parallel group, phase IV clinical drug trial. SETTING The study was conducted at Turku PET Centre, University of Turku, Finland, 2016 to 2017. PARTICIPANTS One hundred and sixty healthy male volunteers were recruited. The metabolomic data of 159 were evaluable. INTERVENTIONS Volunteers were randomised to receive a 1-h exposure to equipotent doses (EC50 for verbal command) of dexmedetomidine (1.5 ng ml(-1); n = 40), propofol (1.7 mu g ml(-1); n = 40), sevoflurane (0.9% end-tidal; n = 39), S-ketamine (0.75 mu g ml(-1); n = 20) or placebo (n = 20). MAIN OUTCOME MEASURES Metabolite subgroups of apolipoproteins and lipoproteins, cholesterol, glycerides and phospholipids, fatty acids, glycolysis, amino acids, ketone bodies, creatinine and albumin and the inflammatory marker GlycA, were analysed with nuclear magnetic resonance spectroscopy from arterial blood samples collected at baseline, after anaesthetic administration and 70 min post-anaesthesia. RESULTS All metabolite subgroups were affected. Statistically significant changes vs. placebo were observed in 11.0, 41.3, 0.65 and 3.9% of the 155 analytes in the dexmedetomidine, propofol, sevoflurane and S-ketamine groups, respectively. Dexmedetomidine increased glucose, decreased ketone bodies and affected lipoproteins and apolipoproteins. Propofol altered lipoproteins, fatty acids, glycerides and phospholipids and slightly increased inflammatory marker glycoprotein acetylation. Sevoflurane was relatively inert. S-ketamine increased glucose and lactate, whereasbranched chain amino acids and tyrosine decreased. CONCLUSION A 1-h exposure to moderate doses of routinely used anaesthetics led to significant and characteristic alterations in the metabolic profile. Dexmedetomidine-induced alterations mirror a2-adrenoceptor agonism. Propofol emulsion altered the lipid profile. The inertness of sevoflurane might prove useful in vulnerable patients. S-ketamine induced amino acid alterations might be linked to its suggested antidepressive properties.Peer reviewe

Liquid-State NMR Analysis of Nanocelluloses

Recent developments in ionic liquid electrolytes for cellulose or biomass dissolution has also allowed for high-resolution ¹H and ¹³C NMR on very high molecular weight cellulose. This permits the development of advanced liquid-state quantitative NMR methods for characterization of unsubstituted and low degree of substitution celluloses, for example, surface-modified nanocelluloses, which are insoluble in all molecular solvents. As such, we present the use of the tetrabutylphosphonium acetate ([P₄₄₄₄]­[OAc]):DMSO-<i>d</i>₆ electrolyte in the 1D and 2D NMR characterization of poly­(methyl methacrylate) (PMMA)-grafted cellulose nanocrystals (CNCs). PMMA-<i>g</i>-CNCs was chosen as a difficult model to study, to illustrate the potential of the technique. The chemical shift range of [P₄₄₄₄]­[OAc] is completely upfield of the cellulose backbone signals, avoiding signal overlap. In addition, application of diffusion-editing for ¹H and HSQC was shown to be effective in the discrimination between PMMA polymer graft resonances and those from low molecular weight components arising from the solvent system. The bulk ratio of methyl methacrylate monomer to anhydroglucose unit was determined using a combination of HSQC and quantitative ¹³C NMR. After detachment and recovery of the PMMA grafts, through methanolysis, DOSY NMR was used to determine the average self-diffusion coefficient and, hence, molecular weight of the grafts compared to self-diffusion coefficients for PMMA GPC standards. This finally led to a calculation of both graft length and graft density using liquid-state NMR techniques. In addition, it was possible to discriminate between triads and tetrads, associated with PMMA tacticity, of the PMMA still attached to the CNCs (before methanolysis). CNC reducing end and sulfate half ester resonances, from sulfuric acid hydrolysis, were also assignable. Furthermore, other biopolymers, such as hemicelluloses and proteins (silk and wool), were found to be soluble in the electrolyte media, allowing for wider application of this method beyond just cellulose analytics

Liquid-State NMR Analysis of Nanocelluloses

Recent developments in ionic liquid electrolytes for cellulose or biomass dissolution has also allowed for high-resolution ¹H and ¹³C NMR on very high molecular weight cellulose. This permits the development of advanced liquid-state quantitative NMR methods for characterization of unsubstituted and low degree of substitution celluloses, for example, surface-modified nanocelluloses, which are insoluble in all molecular solvents. As such, we present the use of the tetrabutylphosphonium acetate ([P₄₄₄₄]­[OAc]):DMSO-<i>d</i>₆ electrolyte in the 1D and 2D NMR characterization of poly­(methyl methacrylate) (PMMA)-grafted cellulose nanocrystals (CNCs). PMMA-<i>g</i>-CNCs was chosen as a difficult model to study, to illustrate the potential of the technique. The chemical shift range of [P₄₄₄₄]­[OAc] is completely upfield of the cellulose backbone signals, avoiding signal overlap. In addition, application of diffusion-editing for ¹H and HSQC was shown to be effective in the discrimination between PMMA polymer graft resonances and those from low molecular weight components arising from the solvent system. The bulk ratio of methyl methacrylate monomer to anhydroglucose unit was determined using a combination of HSQC and quantitative ¹³C NMR. After detachment and recovery of the PMMA grafts, through methanolysis, DOSY NMR was used to determine the average self-diffusion coefficient and, hence, molecular weight of the grafts compared to self-diffusion coefficients for PMMA GPC standards. This finally led to a calculation of both graft length and graft density using liquid-state NMR techniques. In addition, it was possible to discriminate between triads and tetrads, associated with PMMA tacticity, of the PMMA still attached to the CNCs (before methanolysis). CNC reducing end and sulfate half ester resonances, from sulfuric acid hydrolysis, were also assignable. Furthermore, other biopolymers, such as hemicelluloses and proteins (silk and wool), were found to be soluble in the electrolyte media, allowing for wider application of this method beyond just cellulose analytics

Unmanned agricultural tractors in private mobile networks

Abstract The need for high-quality communications networks is urgent in data-based farming. A particular challenge is how to achieve reliable, cost-efficient, secure, and broadband last-mile data transfer to enable agricultural machine control. The trialed ad hoc private communications networks built and interconnected with different alternative wireless technologies, including 4G, 5G, satellite and tactical networks, provide interesting practical solutions for connectivity. A remotely controlled tractor is exemplified as a use case of machine control in the demonstrated private communication network. This paper describes the results of a comparative technology analysis and a field trial in a realistic environment. The study includes the practical implementation of video monitoring and the optimization of the control channel for remote-controlled unmanned agricultural tractors. The findings from this study verify and consolidate the requirements for network technologies and for cybersecurity enablers. They highlight insights into the suitability of different wireless technologies for smart farming and tractor scenarios and identify potential paths for future research

2D Assignment and quantitative analysis of cellulose and oxidized celluloses using solution-state NMR spectroscopy

The limited access to fast and facile general analytical methods for cellulosic and/or biocomposite materials currently stands as one of the main barriers for the progress of these disciplines. To that end, a diverse set of narrow analytical techniques are typically employed that often are time-consuming, costly, and/or not necessarily available on a daily basis for practitioners. Herein, we rigorously demonstrate a general quantitative NMR spectroscopic method for structural determination of crystalline cellulose samples. Our method relies on the use of a readily accessible ionic liquid electrolyte, tetrabutylphosphonium acetate ([P-4444][OAc]):DMSO-d(6), for the direct dissolution of biopolymeric samples. We utilize a series of model compounds and apply now classical (nitroxyl-radical and periodate) oxidation reactions to cellulose samples, to allow for accurate resonance assignment, using 2D NMR. Quantitative heteronuclear single quantum correlation (HSQC) was applied in the analysis of key samples to assess its applicability as a high-resolution technique for following cellulose surface modification. Quantitation using HSQC was possible, but only after applying T(2)correction to integral values. The comprehensive signal assignment of the diverse set of cellulosic species in this study constitutes a blueprint for the direct quantitative structural elucidation of crystalline lignocellulosic, in general, readily available solution-state NMR spectroscopy. [GRAPHICS] .Peer reviewe