490 research outputs found

    Evaluation of soil carbon simulation in CMIP6 Earth system models

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    The response of soil carbon represents one of the key uncertainties in future climate change. The ability of Earth system models (ESMs) to simulate present-day soil carbon is therefore vital for reliably estimating global carbon budgets required for Paris Agreement targets. In this study CMIP6 ESMs are evaluated against empirical datasets to assess the ability of each model to simulate soil carbon and related controls: net primary productivity (NPP) and soil carbon turnover time (Ļ„s). Comparing CMIP6 with the previous generation of models (CMIP5), a lack of consistency in modelled soil carbon remains, particularly the underestimation of northern high-latitude soil carbon stocks. There is a robust improvement in the simulation of NPP in CMIP6 compared with CMIP5; however, an unrealistically high correlation with soil carbon stocks remains, suggesting the potential for an overestimation of the long-term terrestrial carbon sink. Additionally, the same improvements are not seen in the simulation of Ļ„s. These results suggest that much of the uncertainty associated with modelled soil carbon stocks can be attributed to the simulation of below-ground processes, and greater emphasis is required on improving the representation of below-ground soil processes in future developments of models. These improvements would help to reduce the uncertainty in projected carbon release from global soils under climate change and to increase confidence in the carbon budgets associated with different levels of global warming.</p

    Visualizing Kinetically Robust (Co4L6)-L-III Assemblies in Vivo: SPECT Imaging of the Encapsulated [Tc-99m]TcO4- Anion

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    Ā© 2018 American Chemical Society. Noncovalent encapsulation is an attractive approach for modifying the efficacy and physiochemical properties of both therapeutic and diagnostic species. Abiotic self-assembled constructs have shown promise, yet many hurdles between in vitro and (pre)clinical studies remain, not least the challenges associated with maintaining the macromolecular, hollow structure under nonequilibrium conditions. Using a kinetically robust CoIII4L6 tetrahedron we now show the feasibility of encapsulating the most widely used precursor in clinical nuclear diagnostic imaging, the I-emitting [99mTc]TcO4- anion, under conditions compatible with in vivo administration. Subsequent single-photon emission computed tomography imaging of the caged-anion reveals a marked change in the biodistribution compared to the thyroid-accumulating free oxo-anion, thus moving clinical applications of (metallo)supramolecular species a step closer

    Engineering enzymes with non-canonical active site functionality

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    The combination of computational enzyme design and laboratory evolution provides an attractive platform for the creation of protein catalysts with new function. To date, designed mechanisms have relied upon Natureā€™s alphabet of 20 genetically encoded amino acids, which greatly restricts the range of functionality which can be installed into enzyme active sites. Here, we have exploited engineered components of the cellular translation machinery to create a protein catalyst which operates via a non-canonical catalytic nucleophile. We have subsequently shown that powerful laboratory evolution protocols can be readily adapted to allow optimization of enzymes containing non-canonical active site functionality. Crystal structures obtained along the evolutionary trajectory highlight the origins of improved activity. Thus our approach merges beneficial features of organo- and biocatalysis, by combining the intrinsic reactivities and greater versatility of small molecule catalysts with the rate enhancements, reaction selectivities and evolvability of proteins. Please click Additional Files below to see the full abstract

    A high solids field-to-fuel research pipeline to identify interactions between feedstocks and biofuel production

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    Background: Environmental factors, such as weather extremes, have the potential to cause adverse effects on plant biomass quality and quantity. Beyond adversely affecting feedstock yield and composition, which have been extensively studied, environmental factors can have detrimental effects on saccharification and fermentation processes in biofuel production. Only a few studies have evaluated the effect of these factors on biomass deconstruction into biofuel and resulting fuel yields. This field-to-fuel evaluation of various feedstocks requires rigorous coordination of pretreatment, enzymatic hydrolysis, and fermentation experiments. A large number of biomass samples, often in limited quantity, are needed to thoroughly understand the effect of environmental conditions on biofuel production. This requires greater processing and analytical throughput of industrially relevant, high solids loading hydrolysates for fermentation, and led to the need for a laboratory-scale high solids experimentation platform. Results: A field-to-fuel platform was developed to provide sufficient volumes of high solids loading enzymatic hydrolysate for fermentation. AFEX pretreatment was conducted in custom pretreatment reactors, followed by high solids enzymatic hydrolysis. To accommodate enzymatic hydrolysis of multiple samples, roller bottles were used to overcome the bottlenecks of mixing and reduced sugar yields at high solids loading, while allowing greater sample throughput than possible in bioreactors. The roller bottle method provided 42ā€“47% greater liquefaction compared to the batch shake flask method for the same solids loading. In fermentation experiments, hydrolysates from roller bottles were fermented more rapidly, with greater xylose consumption, but lower final ethanol yields and CO2 production than hydrolysates generated with shake flasks. The entire platform was tested and was able to replicate patterns of fermentation inhibition previously observed for experiments conducted in larger-scale reactors and bioreactors, showing divergent fermentation patterns for drought and normal year switchgrass hydrolysates. Conclusion: A pipeline of small-scale AFEX pretreatment and roller bottle enzymatic hydrolysis was able to provide adequate quantities of hydrolysate for respirometer fermentation experiments and was able to overcome hydrolysis bottlenecks at high solids loading by obtaining greater liquefaction compared to batch shake flask hydrolysis. Thus, the roller bottle method can be effectively utilized to compare divergent feedstocks and diverse process conditions

    Clinical utility of vinblastine therapeutic drug monitoring for the treatment of infantile myofibroma patients:A case series

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    Infantile myofibroma is a rare, benign tumour of infancy typically managed surgically. In a minority of cases, more aggressive disease is seen and chemotherapy with vinblastine and methotrexate may be used, although evidence for this is limited. Chemotherapy dosing in infants is challenging, and vinblastine disposition in infants is unknown. We describe the use of vinblastine therapeutic drug monitoring in four cases of infantile myofibroma. Marked inter- and intrapatient variability was observed, highlighting the poorly understood pharmacokinetics of vinblastine in children, the challenges inherent in treating neonates, and the role of adaptive dosing in optimising drug exposure in challenging situations.</p

    ā€œWhat if There's Something Wrong with Her?ā€ā€How Biomedical Technologies Contribute to Epistemic Injustice in Healthcare

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    While there is a steadily growing literature on epistemic injustice in healthcare, there are few discussions of the role that biomedical technologies play in harming patients in their capacity as knowers. Through an analysis of newborn and pediatric genetic and genomic sequencing technologies (GSTs), I argue that biomedical technologies can lead to epistemic injustice through two primary pathways: epistemic capture and value partitioning. I close by discussing the larger ethical and political context of critical analyses of GSTs and their broader implications for just and equitable healthcare delivery

    Neighbourhood prevalence-to-notification ratios for adult bacteriologically-confirmed tuberculosis reveals hotspots of underdiagnosis in Blantyre, Malawi

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    Funding: This work was supported by two grants from Wellcome Trust (ELC grant number WT200901/Z/16/Z) and (PM grant number 200901/Z/16/Z). JRC was funded by UK Medical Research Council (MRC) programme grant MC_UU_00004/07. PJD was supported by a fellowship from the MRC (MR/P022081/1); this UK funded award was part of the EDCTP2 programme supported by the European Union. RMB was funded by Wellcome Trust (203905/16/Z). KCH was supported by the European Research Council (757699) and UK FCDO (Leaving no-one behind: transforming gendered pathways to health for TB). TC was supported by US NIH R01 R01AI147854.Local information is needed to guide targeted interventions for respiratory infections such as tuberculosis (TB). Case notification rates (CNRs) are readily available, but systematically underestimate true disease burden in neighbourhoods with high diagnostic access barriers. We explored a novel approach, adjusting CNRs for under-notification (P:N ratio) using neighbourhood-level predictors of TB prevalence-to-notification ratios. We analysed data from 1) a citywide routine TB surveillance system including geolocation, confirmatory mycobacteriology, and clinical and demographic characteristics of all registering TB patients in Blantyre, Malawi during 2015ā€“19, and 2) an adult TB prevalence survey done in 2019. In the prevalence survey, consenting adults from randomly selected households in 72 neighbourhoods had symptom-plus-chest X-ray screening, confirmed with sputum smear microscopy, Xpert MTB/Rif and culture. Bayesian multilevel models were used to estimate adjusted neighbourhood prevalence-to-notification ratios, based on summarised posterior draws from fitted adult bacteriologically-confirmed TB CNRs and prevalence. From 2015ā€“19, adult bacteriologically-confirmed CNRs were 131 (479/371,834), 134 (539/415,226), 114 (519/463,707), 56 (283/517,860) and 46 (258/578,377) per 100,000 adults per annum, and 2019 bacteriologically-confirmed prevalence was 215 (29/13,490) per 100,000 adults. Lower educational achievement by household head and neighbourhood distance to TB clinic was negatively associated with CNRs. The mean neighbourhood P:N ratio was 4.49 (95% credible interval [CrI]: 0.98ā€“11.91), consistent with underdiagnosis of TB, and was most pronounced in informal peri-urban neighbourhoods. Here we have demonstrated a method for the identification of neighbourhoods with high levels of under-diagnosis of TB without the requirement for a prevalence survey; this is important since prevalence surveys are expensive and logistically challenging. If confirmed, this approach may support more efficient and effective targeting of intensified TB and HIV case-finding interventions aiming to accelerate elimination of urban TB.Peer reviewe

    Effects of coronavirus disease pandemic on tuberculosis notifications, Malawi

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    The coronavirus disease (COVID-19) pandemic might affect tuberculosis (TB) diagnosis and patient care. We analyzed a citywide electronic TB register in Blantyre, Malawi and interviewed TB officers. Malawi did not have an official COVID-19 lockdown but closed schools and borders on March 23, 2020. In an interrupted time series analysis, we noted an immediate 35.9% reduction in TB notifications in April 2020; notifications recovered to near prepandemic numbers by December 2020. However, 333 fewer cumulative TB notifications were received than anticipated. Women and girls were affected more (30.7% fewer cases) than men and boys (20.9% fewer cases). Fear of COVID-19 infection, temporary facility closures, inadequate personal protective equipment, and COVID-19 stigma because of similar symptoms to TB were mentioned as reasons for fewer people being diagnosed with TB. Public health measures could benefit control of both TB and COVID-19, but only if TB diagnostic services remain accessible and are considered safe to attend.Peer reviewe
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