Distribution, Abundance and Diversity of Benthic Macroinvertebrates on the Canadian Continental Shelf and Slope of Southern Davis Strait and Ungava Bay

Stations in a survey of benthic invertebrates on the Canadian continental shelf and slope of southeastern Baffin Island, in Ungava Bay, and on the northern Labrador Shelf, fell into definite groups as a result of an objective analysis of similarity in species composition. The groupings were shown to correspond to major water masses in the area. Groups corresponding to cold surface water masses, to the deep Irminger Atlantic water mass, and to mixtures of these with adjacent water masses were observed. The Irminger Atlantic group dominated on the Baffin Island continental shelf. Species diversity, also measured in the study, was high, with large numbers of species present in low abundance.Key words: marine, benthos, invertebrates, distribution, shelf, slope, Davis Strait, Ungava Bay, subarticMots clés: marin, benthos, invertébrés, distribution, plateau, versant, détroit de Davis, baie d'Ungava, subarctiqu

Cratonic Basins as Effective Sediment Barriers in Continent‑Scale Sediment Routing Systems of Paleozoic North America

Provenance studies demonstrate the important control of plate boundary mountain building on continental sediment routing systems. Less well understood is if subsidence and uplift in cratons also has the potential to affect the organization of sediment routing systems on continental scales. New detrital zircon provenance data from the Michigan Basin in the Midcontinent of North America preserve evidence of intrabasin provenance heterogeneity in Cambrian, Ordovician, and middle Devonian strata. These results suggest that cratonic basins serve as effective sediment barriers that prevent mixing within and across basins from 10 to 100 s of millions of years. Internal sediment mixing, sorting, and dispersal may be achieved by a combination of sedimentary processes and inherited low relief topography. These observations are consistent with provenance data sets from eastern Laurentian Midcontinent basins that show locally and regionally variable provenance signatures during the early Paleozoic. By the late Devonian, provenance signatures throughout the basins homogenized, consistent with the emergence of transcontinental sediment transport systems associated with Appalachian orogenesis at the plate margin. These results demonstrate the importance of cratonic basins on local and regional sediment routing systems suggesting that these features may impede the integration of continental-scale sediment routings systems, particularly during periods of plate margin quiescence

Temocillin: a new candidate antibiotic for local antimicrobial delivery in orthopaedic surgery?

Objectives - To assess the performance of the Gram-negative-specific antibiotic temocillin in polymethylmethacrylate bone cement pre-loaded with gentamicin, as a strategy for local antibiotic delivery. Methods - Temocillin was added at varying concentrations to commercial gentamicin-loaded bone cement. The elution of the antibiotic from cement samples over a 2 week period was quantified by LC-MS. The eluted temocillin was purified by fast protein liquid chromatography and the MICs for a number of antibiotic-resistant Escherichia coli were determined. The impact strength of antibiotic-loaded samples was determined using a Charpy-type impact testing apparatus. Results - LC-MS data showed temocillin eluted to clinically significant concentrations within 1 h in this laboratory system and the eluted temocillin retained antimicrobial activity against all organisms tested. Impact strength analysis showed no significant difference between cement samples with or without temocillin. Conclusions - Temocillin can be added to bone cement and retains its antimicrobial activity after elution. The addition of up to 10% temocillin did not affect the impact strength of the cement. The results show that temocillin is a promising candidate for use in antibiotic-loaded bone cement.</p

Identification and characterisation of a novel adhesin Ifp in Yersinia pseudotuberculosis

BACKGROUND: In order to identify new virulence determinants in Y. pseudotuberculosis a comparison between its genome and that of Yersinia pestis was undertaken. This reveals dozens of pseudogenes in Y. pestis, which are still putatively functional in Y. pseudotuberculosis and may be important in the enteric lifestyle. One such gene, YPTB1572 in the Y. pseudotuberculosis IP32953 genome sequence, encodes a protein with similarity to invasin, a classic adhesion/invasion protein, and to intimin, the attaching and effacing protein from enteropathogenic (EPEC) and enterohaemorraghic (EHEC) Escherichia coli. RESULTS: We termed YPTB1572 Ifp (Intimin family protein) and show that it is able to bind directly to human HEp-2 epithelial cells. Cysteine and tryptophan residues in the C-terminal region of intimin that are essential for function in EPEC and EHEC are conserved in Ifp. Protein binding occurred at distinct foci on the HEp-2 cell surface and can be disrupted by mutation of a single cysteine residue at the C-terminus of the protein. Temporal expression analysis using lux reporter constructs revealed that ifp is expressed at late log phase at 37°C in contrast to invasin, suggesting that Ifp is a late stage adhesin. An ifp defined mutant showed a reduction in adhesion to HEp-2 cells and was attenuated in the Galleria mellonella infection model. CONCLUSION: A new Y. pseudotuberculosis adhesin has been identified and characterised. This Ifp is a new member in the family of invasin/intimin outer membrane adhesins

Characterizing Fishing Effort and Spatial Extent of Coastal Fisheries

Biodiverse coastal zones are often areas of intense fishing pressure due to the high relative density of fishing capacity in these nearshore regions. Although overcapacity is one of the central challenges to fisheries sustainability in coastal zones, accurate estimates of fishing pressure in coastal zones are limited, hampering the assessment of the direct and collateral impacts (e.g., habitat degradation, bycatch) of fishing. We compiled a comprehensive database of fishing effort metrics and the corresponding spatial limits of fisheries and used a spatial analysis program (FEET) to map fishing effort density (measured as boat-meters per km2) in the coastal zones of six ocean regions. We also considered the utility of a number of socioeconomic variables as indicators of fishing pressure at the national level; fishing density increased as a function of population size and decreased as a function of coastline length. Our mapping exercise points to intra and interregional ‘hotspots’ of coastal fishing pressure. The significant and intuitive relationships we found between fishing density and population size and coastline length may help with coarse regional characterizations of fishing pressure. However, spatially-delimited fishing effort data are needed to accurately map fishing hotspots, i.e., areas of intense fishing activity. We suggest that estimates of fishing effort, not just target catch or yield, serve as a necessary measure of fishing activity, which is a key link to evaluating sustainability and environmental impacts of coastal fisheries

Metabolomic Profiling of Bile Acids in Clinical and Experimental Samples of Alzheimer’s Disease

Certain endogenous bile acids have been proposed as potential therapies for ameliorating Alzheimer’s disease (AD) but their role, if any, in the pathophysiology of this disease is not currently known. Given recent evidence of bile acids having protective and anti-inflammatory effects on the brain, it is important to establish how AD affects levels of endogenous bile acids. Using LC-MS/MS, this study profiled 22 bile acids in brain extracts and blood plasma from AD patients (n = 10) and age-matched control subjects (n = 10). In addition, we also profiled brain/plasma samples from APP/PS1 and WT mice (aged 6 and 12 months). In human plasma, we detected significantly lower cholic acid (CA, p = 0.03) in AD patients than age-matched control subjects. In APP/PS1 mouse plasma we detected higher CA (p = 0.05, 6 months) and lower hyodeoxycholic acid (p = 0.04, 12 months) than WT. In human brain with AD pathology (Braak stages V-VI) taurocholic acid (TCA) were significantly lower (p = 0.01) than age-matched control subjects. In APP/PS1 mice we detected higher brain lithocholic acid (p = 0.05) and lower tauromuricholic acid (TMCA; p = 0.05, 6 months). TMCA was also decreased (p = 0.002) in 12-month-old APP/PS1 mice along with 5 other acids: CA (p = 0.02), β-muricholic acid (p = 0.02), Ω-muricholic acid (p = 0.05), TCA (p = 0.04), and tauroursodeoxycholic acid (p = 0.02). The levels of bile acids are clearly disturbed during the development of AD pathology and, since some bile acids are being proposed as potential AD therapeutics, we demonstrate a method that can be used to support work to advance bile acid therapeutics

Structure and spectroscopy of CuH prepared via borohydride reduction

Copper(I) hydride (cuprous hydride, CuH) was the first binary metal hydride to be discovered (in 1844) and is singular in that it is synthesized in solution, at ambient temperature. There are several synthetic paths to CuH, one of which involves reduction of an aqueous solution of CuSO(4)·5H(2)O by borohydride ions. The product from this procedure has not been extensively characterized. Using a combination of diffraction methods (X-ray and neutron) and inelastic neutron scattering spectroscopy, we show that the CuH from the borohydride route has the same bulk structure as CuH produced by other routes. Our work shows that the product consists of a core of CuH with a shell of water and that this may be largely replaced by ethanol. This offers the possibility of modifying the properties of CuH produced by aqueous routes

Effects of Nitrogen and Planting Seed Size on Cotton Growth, Development, and Yield

A standardized experiment was conducted during 2009 and 2010 at 20 location-years across U.S. cotton (Gossypium hirsutum L.)-producing states to compare the N use requirement of contemporary cotton cultivars based on their planting seed size. Treatments consisted of three cotton varieties with planting seed of different numbers of seed per kg and N rates of 0, 45, 90, and 134 kg ha⁻¹. Soil at each trial location was sampled and tested for nitrate presence. High levels of soil nitrate (>91 N-NO₃⁻kg ha⁻¹) were found in Arizona and western Texas, and soil nitrate in the range of 45 to 73 kg N-NO₃⁻ ha⁻¹ was found at locations in the central United States. Cotton lint yield responded to applied N at 11 of 20 locations. Considering only sites that responded to applied N, highest lint yields were achieved with 112 to 224 kg ha⁻¹of applied plus pre-plant residual soil NO₃—translating to an optimal N requirement of 23 kg ha⁻¹ per 218 kg bale of lint produced. Among the varieties tested those with medium-sized seed produced higher yields in response to N than did larger and smaller seeded varieties. Varieties with larger seed had longer and stronger fibers, higher fiber length uniformity than small seeded varieties and decreased micronaire. Seed protein and oil increased and decreased slightly in response to increasing amounts of soil nitrate plus applied N, respectively

Hadal Biodiversity, Habitats and Potential Chemosynthesis in the Java Trench, Eastern Indian Ocean

The Java Trench is the only subduction trench in the Indian Ocean that extends to the hadal zone (> 6,000 m water depth), and except for sevenbenthic trawls acquired around the 1950s, there has been little to no sampling at hadal depths undertaken since. In 2019, we undertook a 5-day expedition comprising a scientific dive using a full ocean depth-rated submersible, the DSV Limiting Factor, seven hadal-lander deployments, and high-resolution bathymetric survey. The submersible performed a video transect from the deepest point of the trench, up a 150 m high near-vertical escarpment located on the forearc, and then across a plateau at a depth of ∼7,050 m to make in situ observations of the habitat heterogeneity and biodiversity inhabiting these hadal depths. We found the Java Trench hadal community to be diverse and represented by 10 phyla, 21 classes, 34 orders and 55 families, with many new records and extensions in either depth or geographic range, including a rare encounter of a hadal ascidian. The submersible transect revealed six habitats spanning the terrain. The deepest trench axis comprised fine-grained sediments dominated by holothurians, whereas evidence of active rock slope failure and associated talus deposits were prevalent in near-vertical and vertical sections of the escarpment. Sediment pockets and sediment pouring down the steep wall in “chutes” were commonly observed. The slope terrain was dominated by two species in the order Actiniaria and an asteroid, as well as 36 instances of orange, yellow, and white bacterial mats, likely exploiting discontinuities in the exposed bedrock, that may indicate a prevalence of chemosynthetic input into this hadal ecosystem. Near the top of the escarpment was an overhang populated by > 100 hexactinellid (glass) sponges. The substrate of the plateau returned to fine-grained sediment, but with a decreased density and diversity of epifauna relative to the trench floor. By providing the first visual insights of the hadal habitats and fauna of the Java Trench, this study highlights how the habitat heterogeneity influences patchy species distributions, and the great benefit of using a hadal-rated exploratory vehicle to comprehensively assess the biodiversity of hadal ecosystems

Association between the COVID-19 pandemic and insurance-based disparities in mortality after major surgery among US adults

Importance: The COVID-19 pandemic caused significant disruptions in surgical care. Whether these disruptions disproportionately impacted economically disadvantaged individuals is unknown. Objective: To evaluate the association between the COVID-19 pandemic and mortality after major surgery among patients with Medicaid insurance or without insurance compared with patients with commercial insurance. Design, Setting, and Participants: This cross-sectional study used data from the Vizient Clinical Database for patients who underwent major surgery at hospitals in the US between January 1, 2018, and May 31, 2020. Exposures: The hospital proportion of patients with COVID-19 during the first wave of COVID-19 cases between March 1 and May 31, 2020, stratified as low (≤5.0%), medium (5.1%-10.0%), high (10.1%-25.0%), and very high (\u3e25.0%). Main Outcomes and Measures: The main outcome was inpatient mortality. The association between mortality after surgery and payer status as a function of the proportion of hospitalized patients with COVID-19 was evaluated with a quasi-experimental triple-difference approach using logistic regression. Results: Among 2 950 147 adults undergoing inpatient surgery (1 550 752 female [52.6%]) at 677 hospitals, the primary payer was Medicare (1 427 791 [48.4%]), followed by commercial insurance (1 000 068 [33.9%]), Medicaid (321 600 [10.9%]), other payer (140 959 [4.8%]), and no insurance (59 729 [2.0%]). Mortality rates increased more for patients undergoing surgery during the first wave of the pandemic in hospitals with a high COVID-19 burden (adjusted odds ratio [AOR], 1.13; 95% CI, 1.03-1.24; P = .01) and a very high COVID-19 burden (AOR, 1.38; 95% CI, 1.24-1.53; P \u3c .001) compared with patients in hospitals with a low COVID-19 burden. Overall, patients with Medicaid had 29% higher odds of death (AOR, 1.29; 95% CI, 1.22-1.36; P \u3c .001) and patients without insurance had 75% higher odds of death (AOR, 1.75; 95% CI, 1.55-1.98; P \u3c .001) compared with patients with commercial insurance. However, mortality rates for surgical patients with Medicaid insurance (AOR, 1.03; 95% CI, 0.82-1.30; P = .79) or without insurance (AOR, 0.85; 95% CI, 0.47-1.54; P = .60) did not increase more than for patients with commercial insurance in hospitals with a high COVID-19 burden compared with hospitals with a low COVID-19 burden. These findings were similar in hospitals with very high COVID-19 burdens. Conclusions and Relevance: In this cross-sectional study, the first wave of the COVID-19 pandemic was associated with a higher risk of mortality after surgery in hospitals with more than 25.0% of patients with COVID-19. However, the pandemic was not associated with greater increases in mortality among patients with no insurance or patients with Medicaid compared with patients with commercial insurance in hospitals with a very high COVID-19 burden