Caught in the act: Implications for the increasing abundance of mafic enclaves during the eruption of the Soufriere Hills Volcano, Montserrat

An exceptional opportunity to sample several large blocks sourced from the same region of the growing Soufrière Hills lava dome has documented a significant increase in the presence of mafic enclaves in the host andesite during the course of a long-lived eruptive episode with several phases. In 1997 (Phase I) mafic inclusions comprised ~1 volume percent of erupted material; in 2007 (Phase III) deposits their volumetric abundance increased to 5–7 percent. A broader range of geochemically distinctive types occurs amongst the 2007 enclaves. Crystal-poor enclaves generally have the least evolved (basaltic) compositions; porphyritic enclaves represent compositions intermediate between basaltic and andesitic compositions. The absence of porphyritic enclaves prior to Phase III magmatism at Soufrière Hills Volcano suggests that a mixing event occurred during the course of the current eruptive episode, providing direct evidence consistent with geophysical observations that the system is continuously re-invigorated from depth

Compound-specific Carbon Isotope Compositions of Aldehydes and Ketones in the Murchison Meteorite

Compoundspecific carbon isotope analysis (13C) of meteoritic organic compounds can be used to elucidate the abiotic chemical reactions involved in their synthesis. The soluble organic content of the Murchison carbonaceous chondrite has been extensively investigated over the years, with a focus on the origins of amino acids and the potential role of Streckercyanohydrin synthesis in the early solar system. Previous 13C investigations have targeted amino acid and hydroxy acid Strecker products and reactant HCN; however, 13C values for meteoritic aldehydes and ketones (Strecker precursors) have not yet been reported. As such, the distribution of aldehydes and ketones in the cosmos and their role in prebiotic reactions have not been fully investigated. Here, we have applied an optimized O(2,3,4,5,6pentafluorobenzyl)hydroxylamine (PFBHA) derivatization procedure to the extraction, identification, and 13C analysis of carbonyl compounds in the Murchison meteorite. A suite of aldehydes and ketones, dominated by acetaldehyde, propionaldehyde, and acetone, were detected in the sample. 13C values, ranging from 10.0 to +66.4, were more 13Cdepleted than would be expected for aldehydes and ketones derived from the interstellar medium, based on interstellar 12C/13C ratios. These relatively 13Cdepleted values suggest that chemical processes taking place in asteroid parent bodies (e.g., oxidation of the IOM) may provide a secondary source of aldehydes and ketones in the solar system. Comparisons between 13C compositions of meteoritic aldehydes and ketones and other organic compound classes were used to evaluate potential structural relationships and associated reactions, including Strecker synthesis and alterationdriven chemical pathways

Enrichment of Non-Terrestrial L-Proteinogenic Amino Acids by Aqueous Alteration on the Tagish Lake Meteorite Parent Body

The distribution and isotopic and enantiomeric compositions of amino acids found in three distinct fragments of the Tagish Lake C2-type carbonaceous chondrite were investigated via liquid chromatography fluorescence detection time-of-flight mass spectrometry and gas chromatography isotope ratio mass spectrometry. Large L-enantiomeric excesses (L(sub ee) approx. 43 to 59%) of the a-hydrogen aspartic and glutamic amino acids were measured in Tagish Lake, whereas alanine, another alpha-hydrogen protein amino acid, was found to be nearly racemic (D approx. L) using both techniques. Carbon isotope measurements of D- and L-aspartic acid and D- and L-alanine in Tagish Lake fall well outside of the terrestrial range and indicate that the measured aspartic acid enantioenrichment is indigenous to the meteorite. Alternate explanations for the Lexcesses of aspartic acid such as interference from other compounds present in the sample, analytical biases, or terrestrial amino acid contamination were investigated and rejected. These results can be explained by differences in the solid-solution phase behavior of aspartic acid, which can form conglomerate enantiopure solids during crystallization, and alanine, which can only form racemic crystals

New Insights into the Heterogeneity of the Tagish Lake Meteorite: Soluble Organic Compositions of Variously Altered Specimens

The Tagish Lake carbonaceous chondrite exhibits a unique compositional heterogeneity that may be attributed to varying degrees of aqueous alteration within the parent body asteroid. Previous analyses of soluble organic compounds from four Tagish Lake meteorite specimens (TL5b, TL11h, TL11i, TL11v) identified distinct distributions and isotopic compositions that appeared to be linked to their degree of parent body processing (Herd et al. 2011; Glavin et al. 2012; Hilts et al. 2014). In the present study, we build upon these initial observations and evaluate the molecular distribution of amino acids, aldehydes and ketones, monocarboxylic acids, and aliphatic and aromatic hydrocarbons, including compoundspecific 13C compositions, for three additional Tagish Lake specimens: TL1, TL4, and TL10a. TL1 contains relatively high abundances of soluble organics and appears to be a moderately altered specimen, similar to the previously analyzed TL5b and TL11h lithologies. In contrast, specimens TL4 and TL10a both contain relatively low abundances of all of the soluble organic compound classes measured, similar to TL11i and TL11v. The organicdepleted composition of TL4 appears to have resulted from a relatively low degree of parent body aqueous alteration. In the case of TL10a, some unusual properties (e.g., the lack of detection of intrinsic monocarboxylic acids and aliphatic and aromatic hydrocarbons) suggest that it has experienced extensive alteration and/or a distinct organicdepleted alteration history. Collectively, these varying compositions provide valuable new insights into the relationships between asteroidal aqueous alteration and the synthesis and preservation of soluble organic compounds

Written education materials for stroke patients and their carers: perspectives and practices of health professionals

Inadequacies in the provision of written education materials to stroke patients and their carers have been reported. In this study, 20 stroke team health professionals were surveyed regarding their use of and perspectives on written education materials. Seventy percent of participants provided materials to 25% or fewer stroke patients and 90% believed that patients and carers are only occasionally or rarely provided with sufficient written information. Health professionals were uncertain which team members provided written information and identified the need to improve the quality of materials used. Stroke teams should implement a system that facilitates the routine provision of quality written materials to patients and carers, communication among team members, and documentation and verbal reinforcement of the information provided

Development and fabrication of a Bi-2223 racetrack coil for generator applications

The development and fabrication of a layer-wound, epoxy-impregnated Bi-2223 high-temperature superconducting (HTS) racetrack coil which generates 40,000 ampere-turns of magnetomotive force (MMF) at 25 K is described. The coil was wound using Ag-sheathed Bi-2223 tape conductor laminated with copper foils for strength enhancement and insulated using a paper-wrap method. After epoxy impregnation, the coil was tested over a range of 16--25 K in a vacuum dewar using a closed-cycle helium refrigeration system. Descriptions of the tape lamination and insulation processing, the coil winding and impregnation, and the experimental test setup are given

The Gift:Transforming Lives through Organ Donation

It is my great pleasure to introduce this comic. Our project originated from an honest conversation with my friend and colleague Prof Chris Murray: how to communicate complex issues surrounding the issue of organ donation? Over the last seven years I have had the honour of being an ambassador for the Organ Donation campaign by telling my son, Andrew’s, story.Through my role as an Organ Donation ambassador I meet courageous and selfless people. Some are in desperate need of hope, some are in the position to provide hope, and those who, through their professionalism and dedication, transform lives.Our sincere thanks for the support of the following organisations: University of Dundee; the NHS Blood and Transplant Specialist Nurses in Organ Donation; Dundee Comics Creative Space; Good Life, Good Death, Good Grief, and the Organ Donation Comics team. it is only through their support that this projectcame to fruition.In the following pages we share heartfelt stories and life experiences related to organ donation. By doing so we hope to bring awareness to a wider audience and prompt honest conversations about organ donation.Finally, I would like thank my sons Andrew and Stuart for warming my heart. Through tears and laughter we present to you… The Gift

A multiorganism pipeline for antiseizure drug discovery:Identification of chlorothymol as a novel γ-aminobutyric acidergic anticonvulsant

OBJECTIVE:Current medicines are ineffective in approximately one-third of people with epilepsy. Therefore, new antiseizure drugs are urgently needed to address this problem of pharmacoresistance. However, traditional rodent seizure and epilepsy models are poorly suited to high-throughput compound screening. Furthermore, testing in a single species increases the chance that therapeutic compounds act on molecular targets that may not be conserved in humans. To address these issues, we developed a pipeline approach using four different organisms. METHODS:We sequentially employed compound library screening in the zebrafish, Danio rerio, chemical genetics in the worm, Caenorhabditis elegans, electrophysiological analysis in mouse and human brain slices, and preclinical validation in mouse seizure models to identify novel antiseizure drugs and their molecular mechanism of action. RESULTS:Initially, a library of 1690 compounds was screened in an acute pentylenetetrazol seizure model using D rerio. From this screen, the compound chlorothymol was identified as an effective anticonvulsant not only in fish, but also in worms. A subsequent genetic screen in C elegans revealed the molecular target of chlorothymol to be LGC-37, a worm γ-aminobutyric acid type A (GABAA ) receptor subunit. This GABAergic effect was confirmed using in vitro brain slice preparations from both mice and humans, as chlorothymol was shown to enhance tonic and phasic inhibition and this action was reversed by the GABAA receptor antagonist, bicuculline. Finally, chlorothymol exhibited in vivo anticonvulsant efficacy in several mouse seizure assays, including the 6-Hz 44-mA model of pharmacoresistant seizures. SIGNIFICANCE:These findings establish a multiorganism approach that can identify compounds with evolutionarily conserved molecular targets and translational potential, and so may be useful in drug discovery for epilepsy and possibly other conditions

Strain field analysis on Montserrat (W.I.) as tool for assessing permeable flow paths in the magmatic system of Soufrière Hills Volcano

Strain dilatometers have been operated on the volcanic island of Montserrat (West Indies) for more than a decade and have proven to be a powerful technique to approach short-term dynamics in the deformational field in response to pressure changes in the magmatic system of the andesitic dome-building Soufrière Hills Volcano (SHV). We here demonstrate that magmatic activity in each of the different segments of the SHV magmatic system (shallow dyke-conduit, upper and lower magma chambers) generates a characteristic strain pattern that allows the identification of operating sources in the plumbing system based on a simple scheme of amplitude ratios. We use this method to evaluate strain data from selected Vulcanian explosions and gas emission events that occurred at SHV between 2003 and 2012. Our results show that the events were initiated by a short phase of contraction of either one or both magma chambers and a simultaneous inflation of the shallow feeder system. The initial phase of the events usually lasted only tens to hundreds of seconds before the explosion/gas emission started and the system recovered. The short duration of this process points at rapid transport of fluids rather than magma ascent to generate the pressure changes. We suggest the propagation of tensile hydraulic fractures as viable mechanism to provide a pathway for fluid migration in the magmatic system at the observed time scale. Fluid mobilization was initiated by a sudden destabilization of large pockets of already segregated fluid in the magma chambers. Our study demonstrates that geodetic observables can provide unprecedented insights into complex dynamic processes within a magmatic system commonly assessed by theoretical modeling and petrologic observations. Key Points Strain data analysis from explosions/degassing events at Soufriere Hills Volcano Pressure release deep within the magmatic system sec-min prior to events Rapid gas rise from magma reservoir to surface via tensile hydraulic fractures © 2014. American Geophysical Union. All Rights Reserved