Pre-operative gastric ultrasound in patients at risk of pulmonary aspiration: a prospective observational cohort study.

Point-of-care gastric sonography offers an objective approach to assessing individual pulmonary aspiration risk before induction of general anaesthesia. We aimed to evaluate the potential impact of routine pre-operative gastric ultrasound on peri-operative management in a cohort of adult patients undergoing elective or emergency surgery at a single centre. According to pre-operative gastric ultrasound results, patients were classified as low risk (empty, gastric fluid volume ≤ 1.5 ml.kg-1 body weight) or high risk (solid, mixed or gastric fluid volume > 1.5 ml.kg-1 body weight) of aspiration. After sonography, examiners were asked to indicate changes in aspiration risk management (none; more conservative; more liberal) to their pre-defined anaesthetic plan and to adapt it if patient safety was at risk. We included 2003 patients, 1246 (62%) of which underwent elective and 757 (38%) emergency surgery. Among patients who underwent elective surgery, 1046/1246 (84%) had a low-risk and 178/1246 (14%) a high-risk stomach, with this being 587/757 (78%) vs. 158/757 (21%) among patients undergoing emergency surgery, respectively. Routine pre-operative gastric sonography enabled changes in anaesthetic management in 379/2003 (19%) of patients, with these being a more liberal approach in 303/2003 (15%). In patients undergoing elective surgery, pre-operative gastric sonography would have allowed a more liberal approach in 170/1246 (14%) and made a more conservative approach indicated in 52/1246 (4%), whereas in patients undergoing emergency surgery, 133/757 (18%) would have been managed more liberally and 24/757 (3%) more conservatively. We showed that pre-operative gastric ultrasound helps to identify high- and low-risk situations in patients at risk of aspiration and adds useful information to peri-operative management. Our data suggest that routine use of pre-operative gastric ultrasound may improve individualised care and potentially impact patient safety

Ferroelectricity induced by interatomic magnetic exchange interaction

Multiferroics, where two or more ferroic order parameters coexist, is one of the hottest fields in condensed matter physics and materials science[1-9]. However, the coexistence of magnetism and conventional ferroelectricity is physically unfavoured[10]. Recently several remedies have been proposed, e.g., improper ferroelectricity induced by specific magnetic[6] or charge orders[2]. Guiding by these theories, currently most research is focused on frustrated magnets, which usually have complicated magnetic structure and low magnetic ordering temperature, consequently far from the practical application. Simple collinear magnets, which can have high magnetic transition temperature, have never been considered seriously as the candidates for multiferroics. Here, we argue that actually simple interatomic magnetic exchange interaction already contains a driving force for ferroelectricity, thus providing a new microscopic mechanism for the coexistence and strong coupling between ferroelectricity and magnetism. We demonstrate this mechanism by showing that even the simplest antiferromagnetic (AFM) insulator MnO, can display a magnetically induced ferroelectricity under a biaxial strain

Magnetoelectric ordering of BiFeO3 from the perspective of crystal chemistry

In this paper we examine the role of crystal chemistry factors in creating conditions for formation of magnetoelectric ordering in BiFeO3. It is generally accepted that the main reason of the ferroelectric distortion in BiFeO3 is concerned with a stereochemical activity of the Bi lone pair. However, the lone pair is stereochemically active in the paraelectric orthorhombic beta-phase as well. We demonstrate that a crucial role in emerging of phase transitions of the metal-insulator, paraelectric-ferroelectric and magnetic disorder-order types belongs to the change of the degree of the lone pair stereochemical activity - its consecutive increase with the temperature decrease. Using the structural data, we calculated the sign and strength of magnetic couplings in BiFeO3 in the range from 945 C down to 25 C and found the couplings, which undergo the antiferromagnetic-ferromagnetic transition with the temperature decrease and give rise to the antiferromagnetic ordering and its delay in regard to temperature, as compared to the ferroelectric ordering. We discuss the reasons of emerging of the spatially modulated spin structure and its suppression by doping with La3+.Comment: 18 pages, 5 figures, 3 table

Reduction in greenhouse gas emissions from national climate legislation

The international response to climate change has been inadequate, but not zero. There are 1,800 climate change laws worldwide. We use panel data on legislative activity in 133 countries over the period 1999–2016 to identify statistically the short-term and long-term impact of climate legislation. Each new law reduces annual carbon dioxide (CO2) emissions per unit of gross domestic product by 0.78% nationally in the short term (during the first three years) and by 1.79% in the long term (beyond three years). The results are driven by parliamentary acts and by countries with a strong rule of law. In 2016, current climate laws were associated with an annual reduction in global CO2 emissions of 5.9 GtCO2, more than the US CO2 output that year. Cumulative CO2 emissions savings from 1999 to 2016 amount to 38 GtCO2, or one year’s worth of global CO2 output. The impact on other greenhouse gases is much lower

The 4Cs of adaptation tracking: consistency, comparability, comprehensiveness, coherency

Adaptation tracking seeks to characterize, monitor, and compare general trends in climate change adaptation over time and across nations. Recognized as essential for evaluating adaptation progress, there have been few attempts to develop systematic approaches for tracking adaptation. This is reflected in polarized opinions, contradictory findings, and lack of understanding on the state of adaptation globally. In this paper, we outline key methodological considerations necessary for adaptation tracking research to produce systematic, rigorous, comparable, and usable insights that can capture the current state of adaptation globally, provide the basis for characterizing and evaluating adaptations taking place, facilitate examination of what conditions explain differences in adaptation action across jurisdictions, and can underpin the monitoring of change in adaptation over time. Specifically, we argue that approaches to adaptation tracking need to (i) utilize a consistent and operational conceptualization of adaptation, (ii) focus on comparable units of analysis, (iii) use and develop comprehensive datasets on adaptation action, and (iv) be coherent with our understanding of what constitutes real adaptation. Collectively, these form the 4Cs of adaptation tracking (consistency, comparability, comprehensiveness, and coherency)

Structural analysis of the reaction cycle of aminoglycoside 6'- N-acetyltransferase type-li, an aminoglycoside- resistance factor

Antibiotic resistance is a serious concern in nosocomial bacterial infections. The extensive use of antibiotics has led to the emergence of multidrug-resistant bacteria such as Enterococci. Strains of E. faecium are frequently encountered that are resistant to a diverse range of antibiotics, including beta-lactams, glycopeptides, as well as aminoglycosides. The resistance profile of E. faecium to many aminoglycosides is attributed to an acetyltransferase. The enzyme, aminoglycoside 6'-N-acetyltransferase type-Ii (AAC(6')-Ii), uses acetyl coenzyme A (AcCoA) to modify all clinically relevant aminoglycosides that contain a 6'-amino sugar. Such modifications render aminoglycosides incapable of binding to the 30S bacterial ribosome, thereby preventing antibiotics from inducing protein mistranslation and thus abolishing their bactericidal properties.We aimed to explore different possibilities to restore aminoglycoside susceptibility by either protecting aminoglycosides from being modified by AAC(6')-Ii or inhibiting the enzyme so that it can no longer modify aminoglycosides. To this end, we pursued the structural description of the entire AAC(6')-Ii reaction cycle. AAC(6')-Ii employs an ordered sequential mechanism, where AcCoA binds prior to the substrate, and where the modified substrate leaves before coenzyme A (CoASH). Thus, the enzyme cycles through four distinct states: apo, AcCoA complex, ternary complex, and CoASH complex. Two out of the four states (AcCoA and CoASH complexed forms) had already been structurally characterized. In addition, diverse mutagenesis and kinetic studies have determined many aspects of the kinetic mechanism governing the enzyme. However, the most important states (apo and ternary state) remain uncharacterized and no conclusive AAC(6')-Ii reaction mechanism has been proposed.Here, we report structural studies for the two remaining states of AAC(6')-Ii. X-ray crystallographic studies of the apo and ternary complex permitted us to describe conformational changes between the different states, define the active site/binding pocket of the enzyme, and rationalize its broad substrate specificity. Complementary solution methods such as nuclear magnetic resonance (NMR), circular dichroism (CD) and small angle X-ray scattering (SAXS) allowed us to gain a better understanding of the dynamics of conformational changes between the apo and complexed states. Estimating quantitative binding energies between the enzyme and several aminoglycosides enabled us to postulate a complete reaction mechanism and extend this mechanism to other acetyltransferases. Ultimately, this detailed structural analysis of AAC(6')-Ii allows us to propose avenues to rejuvenate aminoglycoside therapy against multidrug-resistant pathogens such as E. faecium.La résistance aux antibiotiques est un grave problème pour les infections nosocomiales bactériennes. L'utilisation excessive d'antibiotiques a conduit à l'émergence de bactéries multirésistantes telles que Enterococci. Plusieurs souches d'E. faecium sont résistantes à un large éventail d'antibiotiques, dont les bêtalactamines, les glycopeptides et les aminoglycosides. Le profil de résistance d'E. faecium à plusieurs aminoglycosides est attribué en majeure partie à une acétyltransférase. Cette enzyme, aminoglycoside 6'-N-acétyltransférase de type-Ii AAC(6')-Ii, se sert de l'acétyl-coenzyme A (AcCoA) pour modifier, en position 6', tous les aminoglycosides utilisés en milieux hospitaliers. Ces modifications rendent les aminoglycosides incapables de se lier à la sous-unité 30S du ribosome bactérien, empêchant ainsi l'antibiotique de modifier la traduction des protéines et entraînant donc la suppression de ses propriétés bactéricides.Le but premier de cette étude était de déterminer par quels moyens il serait possible de redonner aux aminoglycosides leur sensibilité, soit en les protégeant d'une modification par AAC(6')-Ii ou en inhibant directement l'enzyme, de sorte qu'elle ne puisse plus modifier les aminoglycosides. À cette fin, nous avons commencé par décrire, à partir de la structure d'AAC(6')-Ii, le cycle des réactions de l'enzyme menant à l'inactivation des aminoglycosides. AAC(6')-Ii utilise un mécanisme séquentiel ordonné, où AcCoA se lie à l'enzyme avant le substrat et où le substrat modifié quitte le site actif avant la coenzyme A (CoASH). Ainsi, la réaction enzymatique se décrit en quatre états distincts: apo, complexe AcCoA, complexe ternaire et complexe CoASH. Deux de ces états (AcCoA et CoASH complexés) ont déjà été caractérisés structurellement. De plus, diverses mutagenéses et études cinétiques ont minutieusement déterminé de nombreux aspects des mécanismes cinétiques régissant l'enzyme. Toutefois, les états les plus importants (apo et ternaire) sont toujours indéterminés et aucun mécanisme concluant n'a été proposé pour l'activité d'AAC(6')-Ii.Nous présentons ici les deux états enzymatiques manquants d'AAC(6')-Ii. Les cristallographies par rayons X des complexes apo et ternaire nous ont permis de décrire les changements de conformation entre les différents états, de définir le site de liaison et le site actif de l'enzyme, et de rationaliser son large spectre de substrats. Grâce à des méthodes complémentaires telles que la résonance magnétique nucléaire (RMN), le dichroïsme circulaire (CD) et la diffusion de rayons X à petit angle (SAXS) nous avons pu mieux comprendre la dynamique qui guide les changements de conformation entre les états apo et complexés. Des estimations quantitatives des énergies de liaison entre l'enzyme et les aminoglycosides nous ont ainsi permis de proposer un mécanisme réactionnel complet pour AAC(6')-Ii et d'étendre ce mécanisme à d'autres membres de la famille des acétyltransférases. Pour conclure, ces études détaillées de la structure d'AAC(6')-Ii nous permettent de proposer des pistes vers l'élaboration de solutions pour surmonter la résistance aux aminoglycosides de pathogènes tels que E. faecium

Dissociative electron attachment and electron energy-loss spectra of phenyl azide

Electron-induced chemistry—dissociative electron attachment (DEA)—was studied for phenyl azide. The major fragment corresponded to the loss of N₂ and formation of the phenylnitrene anion. This process has an onset already at zero kinetic energy of the incident electron and is interpreted as proceeding via the A″π* electronic ground state of the phenyl azide anion. Other fragments, N₃⁻ and CN⁻, were observed at higher energies and interpreted as proceeding via low-lying shape resonances or higher lying core-excited resonances. The interpretation of the dissociative attachment spectra was supported by an investigation of the excited electronic states of neutral phenyl azide by electron energy-loss spectroscopy and DFT/MRCI calculations, and a study of shape and core-excited resonances of the phenyl azide anion by means of electron transmission spectroscopy and of cross sections for vibrational and electronic excitation by electron impact. Interesting parallels and differences are found by comparing DEA of phenyl and benzyl azides with the corresponding chloro compounds

Review of the research conducted by the Poplar Technology Center in Chile: 1999-2011

Zamudio, F (reprint author), Univ Talca, Ctr Tecnol Alamo, Poplar Technol Ctr, 2 Norte 685,POB 747, Talca, Chile.Between 1999 and 2002 the Poplar Technology Center (PTC) introduced more than 2000 experimental poplar hybrids originated by the former Poplar Molecular Genetics Cooperative. Between 2002 and 2003, 12 nursery tests were established in central Chile. Initial growth and the presence of pests and diseases were recorded annually. At the end of 2005, about 100 hybrids were selected from nursery tests and planted in four candidacy tests during 2006. Genetic variation of growth and wood properties is still under study. Here, we present a summary of results obtained to date