820 research outputs found

    Electrical stimulation for enhanced denitrification in woodchip bioreactors: Opportunities and challenges

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    Woodchip bioreactors are being implemented for the removal of nitrates in groundwater and tile water drainage. However, low nitrate removals in denitrifying woodchip bioreactors have been observed for short hydraulic retention time (HRT) and low water temperature (°C). One potential approach to improve woodchip bioreactor performance is to provide an alternative and readily available electron source to the denitrifying microorganisms through electrical stimulation. Previous work has demonstrated the capability of bio-electrochemical reactors (BER) to remove a variety of water contaminants, including nitrate, in the presence of a soluble carbon source. The objective of this study was to evaluate the denitrification efficiency of electrically augmented woodchip bioreactors and conduct a simple techno-economic analysis (TEA) to understand the possibilities and limitations for full-scale BER implementation for treatment of agricultural drainage. Up-flow column woodchip bioreactors were studied included two controls (non-energized, and without electrodes), two electrically enhanced bioreactors, each using a single 316 stainless steel anode coupled with graphite cathodes, and two electrically enhanced bioreactors, each with graphite for both anode and cathodes. Both pairs of electrically enhanced bioreactors demonstrated higher denitrification efficiencies than controls when 500 mA of current was applied. While this technology appeared promising, the techno-economic analysis showed that the normalized N removal cost ($/kg N) for BERs was 2–10 times higher than the base cost with no electrical stimulation. With our current reactor design, opportunities to make this technology cost effective require denitrification efficiency of 85% at 100 mA. This work informs the process and design of electrically stimulated woodchip bioreactors with optimized performance to achieve lower capital and maintenance costs, and thus lower N removal cost

    Strongly Correlated Cerium Systems: Non-Kondo Mechanism for Moment Collapse

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    We present an ab initio based method which gives clear insight into the interplay between the hybridization, the coulomb exchange, and the crystal-field interactions, as the degree of 4f localization is varied across a series of strongly correlated cerium systems. The results for the ordered magnetic moments, magnetic structure, and ordering temperatures are in excellent agreement with experiment, including the occurence of a moment collapse of non-Kondo origin. In contrast, standard ab initio density functional calculations fail to predict, even qualitatively, the trend of the unusual magentic properties.Comment: A shorter version of this has been submitted to PR

    Cardioprotective Effects of Cell Permeable NADPH oxidase inhibitors in Myocardial Ischemia/Reperfusion Injury

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    During myocardial ischemia/reperfusion (I/R), the generation of reactive oxygen species (ROS) contributes to post-reperfused cardiac injury and contractile dysfunction. Activation of NADPH oxidase (NOX) during reperfusion generates ROS, and exacerbates I/R injury. We hypothesize that reducing ROS formation through inhibition of NOX will attenuate myocardial I/R injury in isolated perfused rat hearts subjected to I(30min)/R(45min) compared to untreated I/R hearts. The cell-permeable NOX inhibiting peptide, gp91 ds/tat (RKKRRQRRR-CSTRIRRQL-Amide, MW=2452 g/mol, 20μM, n=5), significantly improved post-reperfused cardiac function compared to controls (n=15,

    The β-isoform of BCCIP promotes ADP release from the RAD51 presynaptic filament and enhances homologous DNA pairing

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    Homologous recombination (HR) is a template-driven repair pathway that mends DNA double-stranded breaks (DSBs), and thus helps to maintain genome stability. The RAD51 recombinase facilitates DNA joint formation during HR, but to accomplish this task, RAD51 must be loaded onto the single-stranded DNA. DSS1, a candidate gene for split hand/split foot syndrome, provides the ability to recognize RPA-coated ssDNA to the tumor suppressor BRCA2, which is complexed with RAD51. Together BRCA2-DSS1 displace RPA and load RAD51 onto the ssDNA. In addition, the BRCA2 interacting protein BCCIP normally colocalizes with chromatin bound BRCA2, and upon DSB induction, RAD51 colocalizes with BRCA2-BCCIP foci. Down-regulation of BCCIP reduces DSB repair and disrupts BRCA2 and RAD51 foci formation. While BCCIP is known to interact with BRCA2, the relationship between BCCIP and RAD51 is not known. In this study, we investigated the biochemical role of the β-isoform of BCCIP in relation to the RAD51 recombinase. We demonstrate that BCCIPβ binds DNA and physically and functionally interacts with RAD51 to stimulate its homologous DNA pairing activity. Notably, this stimulatory effect is not the result of RAD51 nucleoprotein filament stabilization; rather, we demonstrate that BCCIPβ induces a conformational change within the RAD51 filament that promotes release of ADP to help maintain an active presynaptic filament. Our findings reveal a functional role for BCCIPβ as a RAD51 accessory factor in HR

    Treatment of hypertension in rural Cambodia: results of a 6-year programme

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    This study was aimed to describe the outcomes of a hypertension treatment programme in two outpatient clinics in Cambodia. We determined proportions of patients who met the optimal targets for blood pressure (BP) control and assessed the evolution of mean systolic and diastolic BP (SBP/DBP) over time. Multivariate analyses were used to identify predictors of BP decrease and risk factors for LTFU. A total of 2858 patients were enrolled between March 2002 and June 2008 of whom 69.2% were female, 30.5% were aged >/=64years and 32.6% were diabetic. The median follow-up time was 600 days. By the end of 2008, 1642 (57.4%) were alive-in-care, 8 (0.3%) had died and 1208 (42.3%) were lost to follow-up. On admission, mean SBP and DBP were 162 and 94 mm Hg, respectively. Among the patients treated, a significant SBP reduction of 26.8 mm Hg (95% CI: 28.4-25.3) was observed at 6 months. Overall, 36.5% of patients reached the BP targets at 24 months. The number of young adults, non-overweight patients and non-diabetics reaching the BP targets was more. Older age (>64 years), uncontrolled DBP (>/=90 mm Hg) on last consultation and coming late for the last consultation were associated with LTFU, whereas non-diabetic patients were 1.5 times more likely to default than diabetics (95% CI: 1.3-1.7). Although the definite magnitude of the BP decrease due to antihypertension medication over time cannot be assessed definitely without a control group, our results suggest that BP reduction can be obtained with essential hypertension treatment in a large-scale programme in a resource-limited setting

    Do patients prefer optimistic or cautious psychiatrists? An experimental study with new and long-term patients

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    Abstract Background Patients seeking treatment may be assumed to prefer a psychiatrist who suggests a new treatment with confidence and optimism. Yet, this might not apply uniformly to all patients. In this study, we tested the hypothesis that new patients prefer psychiatrists who present treatments optimistically, whilst patients with longer-term experience of mental health care may rather prefer more cautious psychiatrists. Methods In an experimental study, we produced video-clips of four psychiatrists, each suggesting a pharmacological and a psychological treatment once with optimism and once with caution. 100 \u2018new\u2019 patients with less than 3\ua0months experience of mental health care and 100 \u2018long-term\u2019 patients with more than one year of experience were shown a random selection of one video-clip from each psychiatrist, always including an optimistic and a cautious suggestion of each treatment. Patients rated their preferences for psychiatrists on Likert type scales. Differences in subgroups with different age (18\u201340 vs. 41\u201365 years), gender, school leaving age (\u226416 vs. >16\ua0years), and diagnosis (ICD 10\ua0F2 vs. others) were explored. Results New patients preferred more optimistic treatment suggestions, whilst there was no preference among long-term patients. The interaction effect between preference for treatment presentations and experience of patients was significant (interaction p -value\u2009=\u20090.003). Findings in subgroups were similar. Conclusion In line with the hypothesis, psychiatrists should suggest treatments with optimism to patients with little experience of mental health care. However, this rule does not apply to longer-term patients, who may have experienced treatment failures in the past

    Atmospheric observations consistent with reported decline in the UK’s methane emissions, 2013 – 2020

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    Atmospheric measurements can be used as a tool to evaluate national greenhouse gas inventories through inverse modelling. Using 8 years of continuous methane (CH4) concentration data, this work assesses the United Kingdom's (UK) CH4 emissions over the period 2013–2020. Using two different inversion methods, we find mean emissions of 2.10 ± 0.09 and 2.12 ± 0.26 Tg yr−1 between 2013 and 2020, an overall trend of −0.05 ± 0.01 and −0.06 ± 0.04 Tg yr−2 and a 2 %–3 % decrease each year. This compares with the mean emissions of 2.23 Tg yr−1 and the trend of −0.03 Tg yr−2 (1 % annual decrease) reported in the UK's 2021 inventory between 2013 and 2019. We examine how sensitive these estimates are to various components of the inversion set-up, such as the measurement network configuration, the prior emissions estimate, the inversion method and the atmospheric transport model used. We find the decreasing trend to be due, primarily, to a reduction in emissions from England, which accounts for 70 % of the UK CH4 emissions. Comparisons during 2015 demonstrate consistency when different atmospheric transport models are used to map the relationship between sources and atmospheric observations at the aggregation level of the UK. The posterior annual national means and negative trend are found to be consistent across changes in network configuration. We show, using only two monitoring sites, that the same conclusions on mean UK emissions and negative trend would be reached as using the full six-site network, albeit with larger posterior uncertainties. However, emissions estimates from Scotland fail to converge on the same posterior under different inversion set-ups, highlighting a shortcoming of the current observation network in monitoring all of the UK. Although CH4 emissions in 2020 are estimated to have declined relative to previous years, this decrease is in line with the longer-term emissions trend and is not necessarily a response to national lockdowns

    Pre-validation of the WHO organ dysfunction based criteria for identification of maternal near miss

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    <p>Abstract</p> <p>Background</p> <p>To evaluate the performance of the WHO criteria for defining maternal near miss and identifying deaths among cases of severe maternal morbidity (SMM) admitted for intensive care.</p> <p>Method</p> <p>Between October 2002 and September 2007, 673 women with SMM were admitted, and among them 18 died. Variables used for the definition of maternal near miss according to WHO criteria and for the SOFA score were retrospectively evaluated. The identification of at least one of the WHO criteria in women who did not die defined the case as a near miss. Organ failure was evaluated through the maximum SOFA score above 2 for each one of the six components of the score, being considered the gold standard for the diagnosis of maternal near miss. The aggregated score (Total Maximum SOFA score) was calculated using the worst result of the maximum SOFA score. Sensitivity, specificity, positive and negative predictive values of these WHO criteria for predicting maternal death and also for identifying cases of organ failure were estimated.</p> <p>Results</p> <p>The WHO criteria identified 194 cases of maternal near miss and all the 18 deaths. The most prevalent criteria among cases of maternal deaths were the use of vasoactive drug and the use of mechanical ventilation (≥1 h). For the prediction of maternal deaths, sensitivity was 100% and specificity 70.4%. These criteria identified 119 of the 120 cases of organ failure by the maximum SOFA score (Sensitivity 99.2%) among 194 case of maternal near miss (61.34%). There was disagreement in 76 cases, one organ failure without any WHO criteria and 75 cases with no failure but with WHO criteria. The Total Maximum SOFA score had a good performance (area under the curve of 0.897) for prediction of cases of maternal near miss according to the WHO criteria.</p> <p>Conclusions</p> <p>The WHO criteria for maternal near miss showed to be able to identify all cases of death and almost all cases of organ failure. Therefore they allow evaluation of the severity of the complication and consequently enable clinicians to build a plan of care or to provide an early transfer for appropriate reference centers.</p
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