20 research outputs found

    Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

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    Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

    Experiment Stands Corrected: Accurate Prediction of the Aqueous pKa Values of Sulfonamide Drugs Using Equilibrium Bond Lengths

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    We show here for the first time that strongly correlated linear relationships exist between equilibrium bond lengths of the sulfonamide group and aqueous pKa values. Models are constructed for three variants of the SO2NHR group: primary benzene sulfonamide derivatives (e.g. diuretic drugs furosemide and hydrochlorothiazide), N-phenyl substituted 4-amino-N-phenylbenzenesulfonamide analogues (e.g. the sulfa antibiotic sulfadiazine) and phenylsulfonylureas (e.g. insulin secretogogue, glimepiride). In the context of these compounds, we present solutions to some of the more complex challenges in pKa prediction: (i) prediction for multiprotic compounds, (ii) predicting macroscopic values for compounds that tautomerize, and (iii) quantum chemical pKa prediction for compounds with more than 50 atoms. Using bond lengths as a powerful descriptor of ionization feasibility, we also identify that literature values for drug compounds celecoxib, glimepiride and glipizide are inaccurate. Our newly measured experimental values match our initial predictions to within 0.26 pKa units, whereas previous values were found to deviate by up to 1.68 pKa units. For glimepiride, our corrected value denotes a percentage of ionization at intracellular pH, which is only now in excellent agreement with its known therapeutic efficacy. We propose that linear relationships between bond lengths and pKa should emerge for any set of congeners, thus providing a powerful method of pKa prediction obviating the need for thermodynamic cycles

    Enhancing Carbon Acid pK<sub>a</sub> Prediction by Augmentation of Sparse Experimental Datasets with Accurate AIBL (QM) Derived Values

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    The prediction of the aqueous pKa of carbon acids by Quantitative Structure Property Relationship or cheminformatics-based methods is a rather arduous problem. Primarily, there are insufficient high-quality experimental data points measured in homogeneous conditions to allow for a good global model to be generated. In our computationally efficient pKa prediction method, we generate an atom-type feature vector, called a distance spectrum, from the assigned ionisation atom, and learn coefficients for those atom-types that show the impact each atom-type has on the pKa of the ionisable centre. In the current work, we augment our dataset with pKa values from a series of high performing local models derived from the Ab Initio Bond Lengths method (AIBL). We find that, in distilling the knowledge available from multiple models into one general model, the prediction error for an external test set is reduced compared to that using literature experimental data alone

    The AIBLHiCoS Method: Predicting Aqueous p<i>K</i><sub>a</sub> Values from Gas-Phase Equilibrium Bond Lengths

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    The proposed AIBLHiCoS method predicts a given compound’s p<i>K</i><sub>a</sub> in aqueous solution from a single ab initio bond length only, after geometry optimization in the gas phase. Here we provide simple and predictive equations for naphthols and chemically similar biomolecules. Each linear equation corresponds to a <i>High-Correlation Subset</i> (HiCoS) that expresses the novel type of linear free energy relationship discovered here. The naphthol family exhibits a clear and strong relationship with the phenol family, with the “active” C–O bond always producing the highest correlations. The proposed method can isolate erroneous experiments and operate in non-aqueous solution and at different temperatures. Moreover, the existence of “active fragments” is demonstrated in a variety of sizable biomolecules for which the p<i>K</i><sub>a</sub> is successfully predicted

    Solving the Problem of Aqueous pKa Prediction for Tautomerizable Compounds Using Equilibrium Bond Lengths

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    Our new pKa predictor called AIBL outperforms Marvin for the well-known challenge of tautomerizable compounds. The powerful descriptors used here are simply ab initio equilibrium bond lengths. We also correct the literature experimental value for the herbicide Profoxydim, from a previous value 5.91 to a new value of 4.82. This is a fine and rare example of theory correcting experiment

    How In-Home Technologies Mediate Caregiving Relationships in Later Life

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    In-home technologies can support older adults' activities of daily living, provide physical safety and security, and connect elders to family and friends. They facilitate aging in place while reducing caregiver burden. One of older adults' primary concerns about in-home technologies is their potential to reduce human contact, particularly from cherished caregivers. In this exploratory in-situ study, we provided an ecosystem of networked monitoring technologies to six older adults and their caregivers. We analyzed the amount and content of communication between them. The amount of non-computer-mediated communication did not decrease through the six week study. The content of communication coalesced into four themes: communication about the technologies, communication facilitated by technologies, intrusiveness of technologies, and fun and playfulness with the technologies. Results suggest that in-home technologies, designed with sensitivity to older adults' primary motivations, have the potential to shape and tailor important relationships in later life.Update copyright statement and embargo date when published version is available - OR 19/02/201
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