1,194 research outputs found

    Controlled production of the elusive metastable form II of acetaminophen (paracetamol) : a fully scalable templating approach in a cooling environment

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    A scalable, transferable, cooling crystallisation route to the elusive, metastable, form II of the API acetaminophen (paracetamol) has been developed using a multicomponent "templating" approach, delivering 100% polymorphic phase pure form II at scales up to 120 g. Favourable solubility and stability properties are found for the form II samples

    Comparison of offshore wind farm layout optimization using a genetic algorithm and a particle swarm optimizer

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    This article explores the application of a binary genetic algorithm and a binary particle swarm optimizer to the optimization of an offshore wind farm layout. The framework developed as part of this work makes use of a modular design to include a detailed assessment of a wind farm’s layout including validated analytic wake modeling, cost assessment, and the design of the necessary electrical infrastructure considering constraints. This study has found that both algorithms are capable of optimizing the layout with respect to levelized cost of energy when using a detailed, complex evaluation function. Both are also capable of identifying layouts with lower levelized costs of energy than similar studies that have been published in the past and are therefore both applicable to this problem. The performance of both algorithms has highlighted that both should be further tuned and benchmarked in order to better characterize their performance

    Making Space for Failure in the Scholarship of Teaching and Learning: A Blueprint

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    In this essay, we offer a typology of failure in the scholarship of teaching and learning (SoTL) to serve as the foundation for a new line of inquiry to be featured in this new section of Teaching & Learning Inquiry — SoTL in Process. Through the typology, we advocate for making space to talk about failure and its many forms in SoTL. Read the corresponding ISSOTL blog post here

    Simulations to Evaluate HIV Vaccine Trial Designs

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    Many HIV vaccine trials have been proposed to evaluate susceptibility of individuals. However, vac cines may also affect an epidemic's course at the population level by altering the infectiousness of vaccinated individuals who become infected. A vac cine trial design that does not estimate both suscep tibility and infectiousness might reject a proposed vaccine that is capable of halting the HIV epidemic. We describe a vaccine trial design called the Retro spective Partner Trial (RPT), which can quantify vaccine effects on both susceptibility and infectious ness. We describe HIVSIM, a simulation environ ment that generates simulated populations and al lows for empirical evaluation of the statistical power of the RPT. HIVSIM explicitly models a number of factors which influence transmission and preva lence, and which have proven difficult to model us ing standard models. These factors include the infec tion stage of infected individuals, partnership selec tion, the duration of partnerships and concurrence, and transmission of HIV. The simulation analysis indicates that the RPT design has substantially greater statistical power for identifying vaccines which, in spite of exhibiting poor protection against infection, are nonetheless capable of halting the HIV epidemic by substantially reducing the infectious ness of vaccinated individuals who become infected.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68501/2/10.1177_003754979807100403.pd

    Interventions to reduce the risk of surgically transmitted Creutzfeldt–Jakob disease: a cost-effective modelling review

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    Background Creutzfeldt–Jakob disease is a fatal neurological disease caused by abnormal infectious proteins called prions. Prions that are present on surgical instruments cannot be completely deactivated; therefore, patients who are subsequently operated on using these instruments may become infected. This can result in surgically transmitted Creutzfeldt–Jakob disease. Objective To update literature reviews, consultation with experts and economic modelling published in 2006, and to provide the cost-effectiveness of strategies to reduce the risk of surgically transmitted Creutzfeldt–Jakob disease. Methods Eight systematic reviews were undertaken for clinical parameters. One review of cost-effectiveness was undertaken. Electronic databases including MEDLINE and EMBASE were searched from 2005 to 2017. Expert elicitation sessions were undertaken. An advisory committee, convened by the National Institute for Health and Care Excellence to produce guidance, provided an additional source of information. A mathematical model was updated focusing on brain and posterior eye surgery and neuroendoscopy. The model simulated both patients and instrument sets. Assuming that there were potentially 15 cases of surgically transmitted Creutzfeldt–Jakob disease between 2005 and 2018, approximate Bayesian computation was used to obtain samples from the posterior distribution of the model parameters to generate results. Heuristics were used to improve computational efficiency. The modelling conformed to the National Institute for Health and Care Excellence reference case. The strategies evaluated included neither keeping instruments moist nor prohibiting set migration; ensuring that instruments were kept moist; prohibiting instrument migration between sets; and employing single-use instruments. Threshold analyses were undertaken to establish prices at which single-use sets or completely effective decontamination solutions would be cost-effective. Results A total of 169 papers were identified for the clinical review. The evidence from published literature was not deemed sufficiently strong to take precedence over the distributions obtained from expert elicitation. Forty-eight papers were identified in the review of cost-effectiveness. The previous modelling structure was revised to add the possibility of misclassifying surgically transmitted Creutzfeldt–Jakob disease as another neurodegenerative disease, and assuming that all patients were susceptible to infection. Keeping instruments moist was estimated to reduce the risk of surgically transmitted Creutzfeldt–Jakob disease cases and associated costs. Based on probabilistic sensitivity analyses, keeping instruments moist was estimated to on average result in 2.36 (range 0–47) surgically transmitted Creutzfeldt–Jakob disease cases (across England) caused by infection occurring between 2019 and 2023. Prohibiting set migration or employing single-use instruments reduced the estimated risk of surgically transmitted Creutzfeldt–Jakob disease cases further, but at considerable cost. The estimated costs per quality-adjusted life-year gained of these strategies in addition to keeping instruments moist were in excess of £1M. It was estimated that single-use instrument sets (currently £350–500) or completely effective cleaning solutions would need to cost approximately £12 per patient to be cost-effective using a £30,000 per quality-adjusted life-year gained value. Limitations As no direct published evidence to implicate surgery as a cause of Creutzfeldt–Jakob disease has been found since 2005, the estimations of potential cases from elicitation are still speculative. A particular source of uncertainty was in the number of potential surgically transmitted Creutzfeldt–Jakob disease cases that may have occurred between 2005 and 2018. Conclusions Keeping instruments moist is estimated to reduce the risk of surgically transmitted Creutzfeldt–Jakob disease cases and associated costs. Further surgical management strategies can reduce the risks of surgically transmitted Creutzfeldt–Jakob disease but have considerable associated costs. Study registration This study is registered as PROSPERO CRD42017071807. Funding This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 11. See the NIHR Journals Library website for further project information

    Integrase-deficient lentiviral vectors mediate efficient gene transfer to human vascular smooth muscle cells with minimal genotoxic risk

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    We have previously shown that injury-induced neointima formation was rescued by adenoviral-Nogo-B gene delivery. Integrase-competent lentiviral vectors (ICLV) are efficient at gene delivery to vascular cells but present a risk of insertional mutagenesis. Conversely, integrase-deficient lentiviral vectors (IDLV) offer additional benefits through reduced mutagenesis risk, but this has not been evaluated in the context of vascular gene transfer. Here, we have investigated the performance and genetic safety of both counterparts in primary human vascular smooth muscle cells (VSMC) and compared gene transfer efficiency and assessed the genotoxic potential of ICLVs and IDLVs based on their integration frequency and insertional profile in the human genome. Expression of enhanced green fluorescent protein (eGFP) mediated by IDLVs (IDLV-eGFP) demonstrated efficient transgene expression in VSMCs. IDLV gene transfer of Nogo-B mediated efficient overexpression of Nogo-B in VSMCs, leading to phenotypic effects on VSMC migration and proliferation, similar to its ICLV version and unlike its eGFP control and uninfected VSMCs. Large-scale integration site analyses in VSMCs indicated that IDLV-mediated gene transfer gave rise to a very low frequency of genomic integration compared to ICLVs, revealing a close-to-random genomic distribution in VSMCs. This study demonstrates for the first time the potential of IDLVs for safe and efficient vascular gene transfer
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