1,490 research outputs found
Kounis syndrome – Anaphylaxis-induced acute coronary syndrome
Kounis syndrome is an underdiagnosed condition in which anaphylaxis triggers vasospastic acute coronary syndrome, either with or without underlying coronary artery disease. The prevalence of this syndrome among hospitalized patients for allergic/hypersensitivity/anaphylactic reactions in the United States is 1.1%, with a 7% rate of all-cause inpatient mortality. This article presents an anaphylaxis-induced acute coronary syndrome case in a patient with underlying coronary artery disease. The pathophysiological mechanism of anaphylactic-induced acute coronary syndrome involves the inflammatory mediators of type I hypersensitivity reactions
Groundwater dynamics in coastal gravel barriers backed by freshwater lagoons and the potential for saline intrusion: Two cases from the UK
“NOTICE: this is the author’s version of a work that was accepted for publication in Journal of Marine Systems. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Marine Systems, [VOL 123, (01.08.13)] DOI 10.1016/j.jmarsys.2013.04.004". The full text is under embargo until 01.08.15
Directly Measured Denitrification Reveals Oyster Aquaculture and Restored Oyster Reefs Remove Nitrogen at Comparable High Rates
Coastal systems are increasingly impacted by over-enrichment of nutrients, which has cascading effects for ecosystem functioning. Oyster restoration and aquaculture are both hypothesized to mitigate excessive nitrogen (N) loads via benthic denitrification. The degree to which these management activities perform similar functions for removing N, however, has not been extensively examined in New England, a place where nutrient runoff is high and increasing oyster (Crassostrea virginica) restoration and aquaculture activity is taking place. Here, we use a novel in situ methodology to directly measure net N2 and O2 fluxes across the sediment-water interface in a shallow (~1 m) coastal pond in southern Rhode Island. We collected data seasonally during 2013 and 2014 at restored oyster reefs, oyster aquaculture, oyster cultch (shell), and bare sediment. Restored oyster reefs and aquaculture had the highest mean (±SE) denitrification rates, 581.9 (±164.2) and 346 (±168.6) μmol N2−N m−2 h−1, respectively, and are among the highest recorded for oyster-dominated environments. Denitrification rates at sites with oyster cultch were 60.9 (±44.3) μmol N2−N m−2 h−1, which is substantially less than the sites with active oysters but still more than 50% higher than denitrification rates measured in bare sediment (24.4 ± 10.1 μmol N2–N m−2 h−1). The increase in denitrification rates at treatments, however, varied by season and the greatest rates for restored reefs were in the fall. Overall, the greatest aggregate denitrification rates occurred in the fall. Sediment oxygen demand (SOD) followed similar patterns but with greater overall rates in the summer, and displayed a strong linear relationship with denitrification (R2 = 0.93). Our results demonstrate that habitats associated with live oysters have higher net denitrification rates and that oyster reef restoration and oyster aquaculture may provide similar benefits to the ecosystem in terms of N removal. However, gas fluxes may also be affected where three-dimensional structure is introduced via oyster shell cultch and this appears to be seasonally-dependent. These data will be important for managers as they incorporate oysters into nutrient reduction strategies and consider system-level trade-offs in services provided by oyster reef restoration and aquaculture activities
Directly Measured Denitrification Reveals Oyster Aquaculture and Restored Oyster Reefs Remove Nitrogen at Comparable High Rates
Coastal systems are increasingly impacted by over-enrichment of nutrients, which has cascading effects for ecosystem functioning. Oyster restoration and aquaculture are both hypothesized to mitigate excessive nitrogen (N) loads via benthic denitrification. The degree to which these management activities perform similar functions for removing N, however, has not been extensively examined in New England, a place where nutrient runoff is high and increasing oyster (Crassostrea virginica) restoration and aquaculture activity is taking place. Here, we use a novel in situ methodology to directly measure net N2 and O2 fluxes across the sediment-water interface in a shallow (~1 m) coastal pond in southern Rhode Island. We collected data seasonally during 2013 and 2014 at restored oyster reefs, oyster aquaculture, oyster cultch (shell), and bare sediment. Restored oyster reefs and aquaculture had the highest mean (±SE) denitrification rates, 581.9 (±164.2) and 346 (±168.6) μmol N2−N m−2 h−1, respectively, and are among the highest recorded for oyster-dominated environments. Denitrification rates at sites with oyster cultch were 60.9 (±44.3) μmol N2−N m−2 h−1, which is substantially less than the sites with active oysters but still more than 50% higher than denitrification rates measured in bare sediment (24.4 ± 10.1 μmol N2–N m−2 h−1). The increase in denitrification rates at treatments, however, varied by season and the greatest rates for restored reefs were in the fall. Overall, the greatest aggregate denitrification rates occurred in the fall. Sediment oxygen demand (SOD) followed similar patterns but with greater overall rates in the summer, and displayed a strong linear relationship with denitrification (R2 = 0.93). Our results demonstrate that habitats associated with live oysters have higher net denitrification rates and that oyster reef restoration and oyster aquaculture may provide similar benefits to the ecosystem in terms of N removal. However, gas fluxes may also be affected where three-dimensional structure is introduced via oyster shell cultch and this appears to be seasonally-dependent. These data will be important for managers as they incorporate oysters into nutrient reduction strategies and consider system-level trade-offs in services provided by oyster reef restoration and aquaculture activities
Cosmic string formation and the power spectrum of field configurations
We examine the statistical properties of defects formed by the breaking of a
U(1) symmetry when the Higgs field has a power spectrum . We
find a marked dependence of the amount of infinite string on the spectral index
and empirically identify an analytic form for this quantity. We also
confirm that this result is robust to changes in the definition of infinite
string. It is possible that this result could account for the apparent absence
of infinite string in recent lattice-free simulations.Comment: MAJOR REVISION AND NEW RESULTS INCLUDED. 15 pages, uuencoded (LaTeX +
8 postscript figures). Version accepted by Phys. Rev. D. Available at
http://euclid.tp.ph.ic.ac.uk/Papers
The evolution of a network of cosmic string loops
We set up and analyse a model for the non-equilibrium evolution of a network
of cosmic strings initially containing only loops and no infinite strings. Due
to this particular initial condition, our analytical approach differs
significantly from existing ones. We describe the average properties of the
network in terms of the distribution function n(l,t) dl, the average number of
loops per unit volume with physical length between l and l + dl at time t. The
dynamical processes which change the length of loops are then estimated and an
equation, which we call the `rate equation', is derived for (dn/dt). In a
non-expanding universe, the loops should reach the equilibrium distribution
predicted by string statistical mechanics. Analysis of the rate equation gives
results consistent with this. We then study the rate equation in an expanding
universe and suggest that three different final states are possible for the
evolving loop network, each of which may well be realised for some initial
conditions. If the initial energy density in loops in the radiation era is low,
then the loops rapidly disappear. For large initial energy densities, we expect
that either infinite strings are formed or that the loops tend towards a
scaling solution in the radiation era and then rapidly disappear in the matter
era. Such a scenario may be relevant given recent work highlighting the
problems with structure formation from the standard cosmic string scenario.Comment: LaTeX, 27 pages, 10 figures included as .eps file
Acute NaCl Loading Reveals a Higher Blood Pressure for a Given Serum Sodium Level in African American Compared to Caucasian Adults
Purpose: African American individuals are more prone to salt-sensitive hypertension than Caucasian individuals. Small changes in serum sodium (Na+) result in increased blood pressure (BP). However, it remains unclear if there are racial differences in BP responsiveness to increases in serum Na+. Therefore, the purpose of this investigation was to determine if African American adults have altered BP responsiveness to acute changes in serum Na+ compared to Caucasian adults.Methods: We measured beat-by-beat BP, serum Na+, plasma renin activity (PRA), angiotensin II (Ang II), and aldosterone (Aldo) during a 60-min 3% NaCl infusion (hypertonic saline infusion, HSI) in 39 participants (19 African Americans, age: 23 ± 1, 20 Caucasians, age: 25 ± 1). Data reported as African American vs. Caucasian cohort, mean ± SEM.Results: Baseline BP and serum Na+ were similar between groups and increased during HSI in both African American and Caucasian participants (p < 0.01). However, the peak change in serum Na+ was greater in African American participants (Δ5.8 ± 0.34 vs. Δ4.85 ± 0.38 mmol/L, p = 0.03). There was a significant group effect (p = 0.02) and an interaction between race and serum Na+ on systolic BP (p = 0.02). Larger categorical changes in serum Na+ corresponded to changes in systolic BP (p < 0.01) and African American participants demonstrated greater systolic BP responses for a given categorical serum Na+ increase (p < 0.01). Baseline Aldo was lower in African American adults (7.2 ± 0.6 vs. 12.0 ± 1.9 ng/dL, p = 0.03), there was a trend for lower baseline PRA (0.59 ± 0.9 vs. 1.28 ± 0.34 ng/mL/h, p = 0.07), and baseline Ang II was not different (14.2 ± 1.8 vs. 18.5 ± 1.4 pg/mL, p = 0.17). PRA and Aldo decreased during the HSI (p ≤ 0.01), with a greater decline in PRA (Δ–0.31 ± 0.07 vs. Δ–0.85 ± 0.25 ng/mL/h, p < 0.01) and Aldo (Δ–2.5 ± 0.5 vs. Δ–5.0 ± 1.1 ng/dL, p < 0.01) in Caucasian participants. However, the racial difference in PRA (p = 0.57) and Aldo (p = 0.59) reduction were no longer significant following baseline covariate analysis. Conclusion: African American individuals demonstrate augmented serum Na+ to an acute hypertonic saline load and greater systolic BP responsiveness to a given serum Na+. The altered BP response may be attributable to lower basal PRA and Aldo and a subsequently blunted RAAS response during the HSI
The SPARC DynVar Project: A SPARC Project on the Dynamics and Variability of the Coupled Stratosphere-Troposphere
Recommended from our members
Plasma adiponectin levels are associated with circulating inflammatory cytokines in autoantibody positive first-degree relatives of rheumatoid arthritis patients
Background
Extra-articular manifestations of rheumatoid arthritis (RA), potentially due to systemic inflammation, include cardiovascular disease and sarcopenic obesity. Adiponectin, an adipose-derived cytokine, has been implicated in inflammatory processes in RA, but little is known regarding its association with inflammation in a pre-clinical period. Therefore, we investigated whether adiponectin was associated with inflammatory markers in individuals at risk for RA, and whether RA-related autoimmunity modifies these associations.
Methods
We analyzed samples from 144 first-degree relatives (FDRs) of RA probands, of whom 23 were positive for anti-cyclic citrullinated peptide antibody and/or ≥ 2 rheumatoid factor isotypes (IgM, IgG or IgA). We called this phenotype the ‘high risk autoantibody profile (HRP)’ as it has been shown in prior work to be >96% specific for future RA. We measured adiponectin, cytokines, and high-sensitivity C-reactive protein (hsCRP). Using linear mixed effects models, we evaluated interaction between HRP positivity and adiponectin on inflammatory markers, adjusting for age, sex, ethnicity, body mass index, pack-years smoking, and use of cholesterol-lowering medications.
Results
In everyone, adiponectin concentration was inversely associated with hsCRP and IL-1β in adjusted models, where a 1% higher adiponectin was associated with a 26% lower hsCRP (p = 0.04) and a 26% lower IL-1β (p = 0.04). Significant interactions between HRP and adiponectin for associations with GM-CSF, IL-6, and IL-9 were detected in fully adjusted models (p = 0.0006, p = 0.006, p = 0.01, respectively). In HRP positive FDRs but not HRP negative FDRs, a 1% higher adiponectin was associated with 97% higher GM-CSF, 73% higher IL-6, and 54% higher IL-9 concentrations.
Conclusions
Adiponectin associates with inflammatory markers, and these associations differ in individuals with a high-risk autoantibody profile compared with those without. The interaction between adiponectin and autoimmunity warrants further investigation into the potential systemic effects of RA-related autoantibodies and adiponectin on inflammation in the absence of clinically apparent RA
- …