University of Adelaide

About: University of Adelaide is a education organization based out in Adelaide, South Australia, Australia. It is known for research contribution in the topics: Population & Pregnancy. The organization has 27251 authors who have published 79167 publications receiving 2671128 citations. The organization is also known as: The University of Adelaide & Adelaide University.

Aspects of the chemical structure of soil organic materials as revealed by solid-state 13C NMR spectroscopy

Abstract: Solid-state cross-polarisation/magic-angle-spinning3C nuclear magnetic resonance (CP/MAS13C NMR) spectroscopy was used to characterise semi-quantitatively the organic materials contained in particle size and density fractions isolated from five different mineral soils: two Mollisols, two Oxisols and an Andosol The acquired spectra were analysed to determine the relative proportion of carboxyl, aromatic, O-alkyl and alkyl carbon contained in each fraction Although similar types of carbon were present in all of the fractions analysed, an influence of both soil type and particle size was evident The chemical structure of the organic materials contained in the particle size fractions isolated from the Andosol was similar; however, for the Mollisols and Oxisols, the content of O-alkyl, aromatic and alkyl carbon was greatest in the coarse, intermediate and fine fractions, respectively The compositional differences noted in progressing from the coarser to finer particle size fractions in the Mollisols and Oxisols were consistent with the changes noted in other studies where CP/MAS13C NMR was used to monitor the decomposition of natural organic materials Changes in the C:N ratio of the particle size fractions supported the proposal that the extent of decomposition of the organic materials contained in the fine fractions was greater than that contained in the coarse fractions The increased content of aromatic and alkyl carbon in the intermediate size fractions could be explained completely by a selective preservation mechanism; however, the further accumulation of alkyl carbon in the clay fractions appeared to result from both a selective preservation and anin situ synthesis The largest compositional differences noted for the entire organic fraction of the five soils were observed between soil orders The differences within orders were smaller The Mollisols and the Andosol were both dominated by O-alkyl carbon but the Andosol had a lower alkyl carbon content The Oxisols were dominated by both O-alkyl and alkyl carbon A model describing the oxidative decomposition of plant materials in mineral soils is proposed and used to explain the influence of soil order and particle size on the chemical composition of soil organic matter in terms of its extent of decomposition and bioavailability

ESC Working Group Position Paper on Myocardial Infarction With Non-Obstructive Coronary Arteries

Abstract: The management of acute myocardial infarction (AMI)1 has evolved over the past century and particularly in the past 50 years. Important milestones include the development of the electrocardiogram, coronary care units, coronary angiography, reperfusion therapies, and troponin assays. These innovations are the foundation of contemporary AMI management strategies that include a diagnosis centred on elevated troponin values associated with corroborative clinical evidence,1 early use of coronary angiography, and reperfusion therapies.2–4 Pivotal in the evolution of these contemporary strategies were the early AMI coronary angiography studies undertaken by DeWood et al. These pioneering studies demonstrated that, in patients presenting with ST elevation myocardial infarction (STEMI), almost 90% had an occluded coronary artery provided that angiography was undertaken within 4 h of chest pain onset.5 In contrast, in AMI patients who did not present with ST elevation (non-ST elevation myocardial infarction or NSTEMI), only 26% had an occluded coronary artery when angiography was performed within 24 h of symptom onset.6 In both of these landmark studies,5,6 >90% of the acute MI patients had angiographic evidence of obstructive coronary artery disease (CAD), underscoring the importance of the atherosclerotic process in the pathogenesis of AMI. Although DeWood's studies underscore the importance of obstructive CAD in AMI, it is fascinating that ∼10% had no significant CAD on coronary angiography. This is confirmed in several large AMI registries7–9 where 1–13% of AMI's occurred in the absence of obstructive CAD thereby eliciting an important set of questions—what is the mechanism of the myocardial damage in these patients? Do these patients differ from those with obstructive CAD? Should they be …