Triclinic polymorph of bis­(triphenyl­sil­yl) oxide toluene disolvate

A new polymorph of the title compound, C36H30OSi2·2C7H8, is reported, which is triclinic (P-1) instead of possessing the previously reported rhombohedral symmetry [Hönle et al. (1990). Acta Cryst. C46, 1982–1984]. Each of the –SiPh3 units are related by the inversion center. The Si—O—Si moiety is linear with the O atom sitting on an inversion center, and the O—Si—(toluene ring centroid) angle is 3.69 (15)°. Each toluene mol­ecule is 5.622 (2) Å from the Si atom and has its closest contacts with the phenyl rings outside of the van der Waals radii

catena-Poly[copper(II)-bis­(μ-2-ethyl-5-methyl­imidazole-4-sulfonato-κ3 N 3,O 4:O 4′)]

In the title compound, [Cu(C6H9N2O3S)2]n, the copper(II) ion sits on an inversion center and is chelated by the imidazole N and sulfonate O atoms of two ligands in equatorial positions. O atoms of adjacent mol­ecules coordinate in the axial positions. Jahn–Teller tetra­gonal distortion is evident in the coordination geometry [Cu—N and Cu—O equatorial distances of 1.971 (3) and 2.045 (2) Å, respectively, with a Cu—O axial distance of 2.433 (3) Å]. The structure is propagated by an infinite chain of eight-membered (Cu—O—S—O)2 ring systems along the a axis. Only N—H⋯O hydrogen bonding exists between the chains

Metabolic flexibility as a major predictor of spatial distribution in microbial communities

A better understand the ecology of microbes and their role in the global ecosystem could be achieved if traditional ecological theories can be applied to microbes. In ecology organisms are defined as specialists or generalists according to the breadth of their niche. Spatial distribution is often used as a proxy measure of niche breadth; generalists have broad niches and a wide spatial distribution and specialists a narrow niche and spatial distribution. Previous studies suggest that microbial distribution patterns are contrary to this idea; a microbial generalist genus (Desulfobulbus) has a limited spatial distribution while a specialist genus (Methanosaeta) has a cosmopolitan distribution. Therefore, we hypothesise that this counter-intuitive distribution within generalist and specialist microbial genera is a common microbial characteristic. Using molecular fingerprinting the distribution of four microbial genera, two generalists, Desulfobulbus and the methanogenic archaea Methanosarcina, and two specialists, Methanosaeta and the sulfate-reducing bacteria Desulfobacter were analysed in sediment samples from along a UK estuary. Detected genotypes of both generalist genera showed a distinct spatial distribution, significantly correlated with geographic distance between sites. Genotypes of both specialist genera showed no significant differential spatial distribution. These data support the hypothesis that the spatial distribution of specialist and generalist microbes does not match that seen with specialist and generalist large organisms. It may be that generalist microbes, while having a wider potential niche, are constrained, possibly by intrageneric competition, to exploit only a small part of that potential niche while specialists, with far fewer constraints to their niche, are more capable of filling their potential niche more effectively, perhaps by avoiding intrageneric competition. We suggest that these counter-intuitive distribution patterns may be a common feature of microbes in general and represent a distinct microbial principle in ecology, which is a real challenge if we are to develop a truly inclusive ecology

Insights into the evolution of the Thomson Orogen from geochronology, geochemistry, and zircon isotopic studies of magmatic rocks

Zircon U–Pb ages, εHf(t), and δ18O isotopic data together with geochemistry and limited Sm–Nd results from magmatic rocks sampled in deep-basement drill cores from undercover parts of the Thomson Orogen provide strong temporal links with outcropping regions of the orogen and important clues to its evolution and relationship with the Lachlan Orogen. SHRIMP U–Pb zircon ages show that magmatism of Early Ordovician age is widespread across the central, undercover regions of the Thomson Orogen and occurred in a narrow time-window between 480 and 470 Ma. These rocks have evolved εHf(t)zrn (−12.18 to −6.26) and εNd (−11.3 to −7.1), and supracrustal δ18Ozrn (7.01–8.50‰), which is in stark contrast to Early Ordovician magmatic rocks in the Lachlan Orogen that are isotopically juvenile. Two samples have late Silurian ages (425–420 Ma), and four have Devonian ages (408–382 Ma). The late Silurian rocks have evolved εHf(t)zrn (−6.42 to −4.62) and supracrustal δ18Ozrn (9.26–10.29‰) values, while the younger Devonian rocks show a shift toward more juvenile εHf(t)zrn, a trend that is also seen in rocks of this age in the Lachlan Orogen. Interestingly, two early Late Devonian samples have juvenile εHf(t)zrn (0.01–1.92) but supracrustal δ18Ozrn (7.45–8.77‰) indicating rapid recycling of juvenile material. Two distinct Hf–O isotopic mixing trends are observed for magmatic rocks of the Thomson Orogen. One trend appears to have incorporated a more evolved supracrustal component and is defined by samples from the northern two-thirds of the Thomson Orogen, while the other trend is generally less evolved and from samples in the southern third of the Thomson Orogen and matches the isotopic character of rocks from the Lachlan Orogen. The spatial association of the Early Ordovician magmatism with the more evolved metasedimentary signature suggests that at least the northern part of the Thomson Orogen is underlain by older pre-Delamerian metasedimentary rocks

An electrostatic mechanism for Ca(2+)-mediated regulation of gap junction channels.

Gap junction channels mediate intercellular signalling that is crucial in tissue development, homeostasis and pathologic states such as cardiac arrhythmias, cancer and trauma. To explore the mechanism by which Ca(2+) blocks intercellular communication during tissue injury, we determined the X-ray crystal structures of the human Cx26 gap junction channel with and without bound Ca(2+). The two structures were nearly identical, ruling out both a large-scale structural change and a local steric constriction of the pore. Ca(2+) coordination sites reside at the interfaces between adjacent subunits, near the entrance to the extracellular gap, where local, side chain conformational rearrangements enable Ca(2+)chelation. Computational analysis revealed that Ca(2+)-binding generates a positive electrostatic barrier that substantially inhibits permeation of cations such as K(+) into the pore. Our results provide structural evidence for a unique mechanism of channel regulation: ionic conduction block via an electrostatic barrier rather than steric occlusion of the channel pore

The Metabolic Profile of Young, Watered Chickpea Plants Can Be Used as a Biomarker to Predict Seed Number under Terminal Drought

Chickpea is the second-most-cultivated legume globally, with India and Australia being the two largest producers. In both of these locations, the crop is sown on residual summer soil moisture and left to grow on progressively depleting water content, finally maturing under terminal drought conditions. The metabolic profile of plants is commonly, correlatively associated with performance or stress responses, e.g., the accumulation of osmoprotective metabolites during cold stress. In animals and humans, metabolites are also prognostically used to predict the likelihood of an event (usually a disease) before it occurs, e.g., blood cholesterol and heart disease. We sought to discover metabolic biomarkers in chickpea that could be used to predict grain yield traits under terminal drought, from the leaf tissue of young, watered, healthy plants. The metabolic profile (GC-MS and enzyme assays) of field-grown chickpea leaves was analysed over two growing seasons, and then predictive modelling was applied to associate the most strongly correlated metabolites with the final seed number plan

Metagenomic data-mining reveals contrasting microbial populations responsible for trimethylamine formation in human gut and marine ecosystems

Existing metagenome datasets from many different environments contain untapped potential for understanding metabolic pathways and their biological impact. Our interest lies in the formation of trimethylamine (TMA), a key metabolite in both human health and climate change. Here, we focus on bacterial degradation pathways for choline, carnitine, glycine betaine and trimethylamine N-oxide (TMAO) to TMA in human gut and marine metagenomes. We found the TMAO reductase pathway was the most prevalent pathway in both environments. Proteobacteria were found to contribute the majority of the TMAO reductase pathway sequences, except in the stressed gut, where Actinobacteria dominated. Interestingly, in the human gut metagenomes, a high proportion of the Proteobacteria hits were accounted for by the genera Klebsiella and Escherichia. Furthermore Klebsiella and Escherichia harboured three of the four potential TMA-production pathways (choline, carnitine and TMAO), suggesting they have a key role in TMA cycling in the human gut. In addition to the intensive TMAO–TMA cycling in the marine environment, our data suggest that carnitine-to-TMA transformation plays an overlooked role in aerobic marine surface waters, whereas choline-to-TMA transformation is important in anaerobic marine sediments. Our study provides new insights into the potential key microbes and metabolic pathways for TMA formation in two contrasting environments

Sulfonated 1,3-bis­(4-pyrid­yl)propane

In the title compound, 4-[3-(3-sulfonato­pyridin-1-ium-4-yl)prop­yl]pyridin-1-ium-3-sulfonate, C13H14N2O6S2, the mol­ecule is zwitterionic, with the sulfonic acid proton transfered to the basic pyridine N atom. Also, the structure adopts a butterfly-like conformation with the sulfonate groups on opposite sides of the ‘wings’. The dihedral angle between the two pyridinium rings is 83.56 (7)°, and this results in the mol­ecule having a chiral conformation and packing. There is strong inter­molecular hydrogen bonding between the pyridinium H and sulfonate O atoms of adjoining mol­ecules. In addition, there are weaker inter­molecular C—H⋯O inter­actions

Changes in admission thresholds in English Emergency Departments

YesBackground: The most common route to a hospital bed in an emergency is via an emergency department (ED). Many recent initiatives and interventions have the objective of reducing the number of unnecessary emergency admissions. We aimed to assess whether ED admission thresholds had changed over time taking account of the casemix of patients arriving at ED. Methods: We conducted a retrospective cross-sectional analysis of more than 20 million attendances at 47 consultant-led emergency departments in England between April 2010 and March 2015. We used mixed- effects logistic regression to estimate the odds of a patient being admitted to hospital and the impact of a range of potential explanatory variables. Models were developed and validated for four attendance subgroups : ambulance-conveyed children; walk-in children; ambulance-conveyed adults; and walk-in adults. Results: 23.8% of attendances were for children aged under 18 years, 49.7% were female and 30.0% were conveyed by ambulance. The number of ED attendances increased by 1.8% per annum between April 2010 – March 2011 (year 1) and April 2014 –March 2015 (year 5). The proportion of these attendances that were admitted to hospital changed little between year 1 (27.0%) and year 5 (27.5%). However, after adjusting for patient and attendance characteristics the odds of admission over the five year period had reduced by: 15.2% (95% CI 13.4% - 17.0%) for ambulance-conveyed children; 22.6% (95% CI 21.7%-23.5%) for walk-in children; 20.9% (95% CI 4%-21.5%) for ambulance conveyed adults; and 22.9% (95% CI 22.4%-23.5%) for walk-in adults. Conclusions: The casemix-adjusted odds of admission via ED to NHS hospitals in England have decreased since April 2010. EDs are admitting a similar proportion of patients to hospital despite increases in the complexity and acuity of presenting patients. Without these threshold changes, the number of emergency admissions would have been 11.9% higher than was the case in year 5

Doing our work better, together: a relationship-based approach to defining the quality improvement agenda in trauma care

Article presents a study conducted at Gold Coast University Hospital that aimed to define and improve relational aspects of trauma care and facilitate co-creation of targeted interventions designed to improve team relationships and performance