28 research outputs found

    Assessing the impact of diagenesis on foraminiferal geochemistry from a low latitude, shallow-water drift deposit

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    Due to their large heat and moisture storage capabilities, the tropics are fundamental in modulating both regional and global climate. Furthermore, their thermal response during past extreme warming periods, such as super interglacials, is not fully resolved. In this regard, we present high-resolution (analytical) foraminiferal geochemical (δ18O and Mg/Ca) records for the last 1800 kyr from the shallow (487 m) Inner Sea drift deposits of the Maldives archipelago in the equatorial Indian Ocean. Considering the diagenetic susceptibility of these proxies, in carbonate-rich environments, we assess the integrity of a suite of commonly used planktonic and benthic foraminifera geochemical datasets (Globigerinoides ruber (white), Globigerinita glutinata (with bulla), Pulleniatina obliquiloculata (with cortex) and Cibicides mabahethi) and their use for future paleoceanographic reconstructions. Using a combination of spot Secondary Ion Mass Spectrometer, Electron Probe Micro-Analyzer and Scanning Electron Microscope image data, it is evident that authigenic overgrowths are present on both the external and internal test (shell) surfaces, yet the degree down-core as well as the associated bias is shown to be variable across the investigated species and proxies. Given the elevated authigenic overgrowth Mg/Ca (∼12–22 mmol/mol) and δ18O values (closer to the benthic isotopic compositions) the whole-test planktonic G. ruber (w) geochemical records are notably impacted beyond ∼627.4 ka (24.7 mcd). Yet, considering the setting (i.e. bottom water location) for overgrowth formation, the benthic foraminifera δ18O record is markedly less impacted with only minor diagenetic bias beyond ∼790.0 ka (28.7 mcd). Even though only the top of the G. ruber (w) and C. mabahethi records (whole-test data) would be suitable for paleo-reconstructions of absolute values (i.e. sea surface temperature, salinity, seawater δ18O), the long-term cycles, while dampened, appear to be preserved. Furthermore, planktonic species with thicker-tests (i.e. P. obliquiloculata (w/c)) might be better suited, in comparison to thinner-test counter-parts (i.e. G. glutinata (w/b), G. ruber (w)), for traditional whole- test geochemical studies in shallow, carbonate-rich environments. A thicker test equates to a smaller overall bias from the authigenic overgrowth. Overall, if the diagenetic impact is constrained, as done in this study, these types of diagenetically altered geochemical records can still significantly contribute to studies relating to past tropical seawater temperatures, latitudinal scale ocean current shifts and South Asian Monsoon dynamics

    Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

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    Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

    Bidirectional DNA unwinding by a ternary complex of T antigen, nucleolin and topoisomerase I

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    The simian virus 40 large tumour-antigen (T antigen) DNA helicase is a hexameric structure; it has been proposed that, in viral DNA replication, two of these hexamers are combined to form a bipartite holoenzyme that acts concurrently at both forks of a replication bubble. In a search for structural components of this helicase complex, we have identified nucleolin as a specific binding protein for the T-antigen hexamer. We show that nucleolin, in co-operation with human topoisomerase I, mediates the cohesion of the T-antigen helicase holoenzyme during plasmid unwinding. Our results provide biochemical evidence for a direct role of nucleolin in DNA replication, in addition to its known function in ribosome biogenesis. The data presented here suggest that nucleolin enables the formation of a functional 'helicase-swivelase' complex at the replication fork

    Adjusted Relationship between Blood Lead Concentration and Arrest Rate Ratio For Violent Offenses

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    <p>Shown are data for maternal prenatal blood lead concentration (A), early childhood average blood lead concentration (B), and 6-year blood lead concentration (C). Rate ratios are plotted as a function of increasing blood lead from the 5th to the 95th percentiles of blood lead relative to participants at the 5th percentile. Dashed lines are 95% confidence intervals. To convert to μmol/l: (μg/dl) × 0.04826.</p

    Adjusted Relationship between Blood Lead Concentration and Arrest Rate Ratio For Total Arrests

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    <p>Shown are data for maternal prenatal blood lead concentration (A), early childhood average blood lead concentration (B), and 6-year blood lead concentration (C). Rate ratios are plotted as a function of increasing blood lead from the 5th to the 95th percentiles of blood lead relative to participants at the 5th percentile. Dashed lines are 95% confidence intervals. To convert to μmol/l: (μg/dl) × 0.04826.</p

    Clinical outcomes after surgery for primary aldosteronism: Evaluation of the PASO-investigators’ consensus criteria within a worldwide cohort of patients

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    Background: In a first step toward standardization, the Primary Aldosteronism Surgical Outcomes investigators introduced consensus criteria defining the clinical outcomes after adrenalectomy for primary aldosteronism. Within this retrospective cohort study, we evaluated the use of these consensus criteria in daily clinical practice in 16 centers in Europe, Canada, Australia, and the United States. Methods: Patients who underwent unilateral adrenalectomy for primary aldosteronism between 2010 and 2016 were included. Patients with missing data regarding preoperative or postoperative blood pressure or their defined daily dose were excluded. According to the Primary Aldosteronism Surgical Outcomes criteria, patients were classified as complete, partial, or absent clinical success. Results: A total of 380 patients were eligible for analysis. Complete, partial, and absent clinical success was achieved in 30%, 48%, and 22%, respectively. Evaluation of the Primary Aldosteronism Surgical Outcomes criteria showed that in 11% and 47% of patients with partial and absent clinical success, this classification was incorrect or debatable (16% of the total cohort). This concept of a “debatable classification of success” was due mainly to the cutoff of ≥20 mmHg used to indicate a clinically relevant change in systolic blood pressure and the use of percentages instead of absolute values to indicate a change in defined daily dose. Conclusion: Although introduction of the Primary Aldosteronism Surgical Outcomes consensus criteria induced substantial advancement in the standardization of postoperative outcomes, our study suggests that there is room for improvement in the concept for success given the observed limitations when the criteria were tested within our international cohort. In line, determining clinical success remains challenging, especially in patients with opposing change in blood pressure and defined daily dose

    Clinical outcomes after surgery for primary aldosteronism : Evaluation of the PASO-investigators’ consensus criteria within a worldwide cohort of patients

    No full text
    Background: In a first step toward standardization, the Primary Aldosteronism Surgical Outcomes investigators introduced consensus criteria defining the clinical outcomes after adrenalectomy for primary aldosteronism. Within this retrospective cohort study, we evaluated the use of these consensus criteria in daily clinical practice in 16 centers in Europe, Canada, Australia, and the United States. Methods: Patients who underwent unilateral adrenalectomy for primary aldosteronism between 2010 and 2016 were included. Patients with missing data regarding preoperative or postoperative blood pressure or their defined daily dose were excluded. According to the Primary Aldosteronism Surgical Outcomes criteria, patients were classified as complete, partial, or absent clinical success. Results: A total of 380 patients were eligible for analysis. Complete, partial, and absent clinical success was achieved in 30%, 48%, and 22%, respectively. Evaluation of the Primary Aldosteronism Surgical Outcomes criteria showed that in 11% and 47% of patients with partial and absent clinical success, this classification was incorrect or debatable (16% of the total cohort). This concept of a “debatable classification of success” was due mainly to the cutoff of ≥20 mmHg used to indicate a clinically relevant change in systolic blood pressure and the use of percentages instead of absolute values to indicate a change in defined daily dose. Conclusion: Although introduction of the Primary Aldosteronism Surgical Outcomes consensus criteria induced substantial advancement in the standardization of postoperative outcomes, our study suggests that there is room for improvement in the concept for success given the observed limitations when the criteria were tested within our international cohort. In line, determining clinical success remains challenging, especially in patients with opposing change in blood pressure and defined daily dose
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