Publications by authors named "Andrew Plummer"

Wearable robots are emerging as a viable and effective solution for assisting and enabling people who suffer from balance and mobility disorders. Virtual prototyping is a powerful tool to design robots, preventing the costly iterative physical prototyping and testing. Design of wearable robots through modelling, however, often involves computationally expensive and error-prone multi-body simulations wrapped in an optimization framework to simulate human-robot-environment interactions.

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Conventional trajectory planning for lower limb assistive devices usually relies on a finite-state strategy, which pre-defines fixed trajectory types for specific gait events and activities. The advancement of deep learning enables walking assistive devices to better adapt to varied terrains for diverse users by learning movement patterns from gait data. Using a self-attention mechanism, a temporal deep learning model is developed in this study to continuously generate lower limb joint angle trajectories for an ankle and knee across various activities.

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Current guidelines recommend that individuals with moderate COVID-19 disease isolate for 5 days after the first appearance of symptoms or a positive SARS-CoV-2 test. It would be useful to understand the time course of infectious virus production and its correlation with virus detection using a rapid antigen test (RAT) or quantitative reverse transcriptase (qRT)-PCR. In a phase 2 study, 242 vaccinated patients with COVID-19 and at low risk for progression to severe disease initiated 5 days of treatment with pomotrelvir (PBI-0451, a SARS-CoV-2 main protease inhibitor) or placebo within 5 days after symptom onset.

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Pomotrelvir is an orally bioavailable, target antiviral inhibitor of the main protease (M) of coronaviruses, including severe acute respiratory syndrome coronavirus 2, the etiological agent of Coronavirus Disease 2019. The pharmacokinetics, metabolism and elimination of two [C]-labeled microtracers of 5 Ci/700 mg pomotrelvir with separate labeling positions (isotopomers), [lactam carbonyl-C-pomotelvir] and [benzene ring-U-C-pomotrelvir], following a single oral dose in healthy adult males was evaluated in two separate cohorts. Pomotrelvir was rapidly absorbed and eliminated primarily through metabolism and subsequently excreted via urine and feces.

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Pomotrelvir is a new chemical entity and potent direct-acting antiviral inhibitor of the main protease of coronaviruses. Here the cytochrome P450 (CYP)-mediated drug-drug interaction (DDI) potential of pomotrelvir was evaluated for major CYP isoforms, starting with in vitro assays followed by the basic static model assessment. The identified CYP3A4-mediated potential DDIs were evaluated clinically at a supratherapeutic dose of 1050 mg twice daily (b.

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Reliable estimation of desired motion trajectories plays a crucial part in the continuous control of lower extremity assistance devices such as prostheses and orthoses. Moreover, reliable estimation methods are also required to predict hard-to-measure biomechanical quantities (e.g.

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Human Locomotion Mode Recognition (LMR) has the potential to be used as a control mechanism for lower-limb active prostheses. Active prostheses can assist and restore a more natural gait for amputees, but as a medical device it must minimize user risks, such as falls and trips. As such, any control system must have high accuracy and robustness, with a detailed understanding of its internal operation.

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Background: With large numbers of COVID-19 patients requiring mechanical ventilation and ventilators possibly being in short supply, in extremis two patients may have to share one ventilator. Careful matching of patient ventilation requirements is necessary. However, good matching is difficult to achieve as lung characteristics can have a wide range and may vary over time.

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Low-dimensional representations of speech data, such as formant values extracted by linear predictive coding analysis or spectral moments computed from whole spectra viewed as probability distributions, have been instrumental in both phonetic and phonological analyses over the last few decades. In this paper, we present a framework for computing low-dimensional representations of speech data based on two assumptions: that speech data represented in high-dimensional data spaces lie on shapes called that can be used to map speech data to low-dimensional coordinate spaces, and that manifolds underlying speech data are generated from a combination of language-specific lexical, phonological, and phonetic information as well as culture-specific socio-indexical information that is expressed by talkers of a given speech community. We demonstrate the basic mechanics of the framework by carrying out an analysis of children's productions of sibilant fricatives relative to those of adults in their speech community using the phoneigen package - a publicly available implementation of the framework.

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We used individual-based computer simulation models at community, regional and national levels to evaluate the likely impact of coordinated pre-emptive school dismissal policies during an influenza pandemic. Such policies involve three key decisions: when, over what geographical scale, and how long to keep schools closed. Our evaluation includes uncertainty and sensitivity analyses, as well as model output uncertainties arising from variability in serial intervals and presumed modifications of social contacts during school dismissal periods.

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Recent work in the forensic analysis of Gunshot residues (GSR) has suggested that the sub-surface or internal composition and morphology of these residues be explored. A particular area of interest is in heavy metal free, or non-toxic ammunition, which are becoming more frequently encountered in the marketplace. As the formulation of the primer compound changes the conditions of the firearm discharge, there is the possibility that different primer formulations may result in the formation of different GSR particles with distinct internal morphologies and compositions.

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The majority of 0.22 calibre rimfire ammunition available in Australia, and overseas, tends to use glass powder rather than antimony sulfide frictionator in the primer. This glass can be the nucleus of a GSR particle, with other primer components condensing around and onto the glass structure.

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Objective: Assess the performance of HIV-1 RNA repeat testing of stored samples in cases of low-level viremia during clinical trials.

Design: Prospective and retrospective analysis of randomized clinical trial samples and reference standards.

Methods: To evaluate assay variability of the Cobas AmpliPrep/Cobas TaqMan HIV-1 Test, v2.

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Methods from automatic speech recognition (ASR), such as segmentation and forced alignment, have facilitated the rapid annotation and analysis of very large adult speech databases and databases of caregiver-infant interaction, enabling advances in speech science that were unimaginable just a few decades ago. This paper centers on two main problems that must be addressed in order to have analogous resources for developing and exploiting databases of young children's speech. The first problem is to understand and appreciate the differences between adult and child speech that cause ASR models developed for adult speech to fail when applied to child speech.

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In 2 double-blind phase 3 trials, 1733 antiretroviral-naive adults were randomized to tenofovir alafenamide (TAF) or tenofovir disoproxil fumarate (TDF), each coformulated with elvitegravir/cobicistat/emtricitabine (E/C/F). At 144 weeks, TAF was superior to TDF in virologic efficacy, with 84.2% vs 80.

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Background: Emtricitabine with tenofovir disoproxil fumarate is a standard-of-care nucleoside reverse transcriptase inhibitor (NRTI) backbone. However, tenofovir disoproxil fumarate is associated with renal and bone toxic effects; the novel prodrug tenofovir alafenamide achieves 90% lower plasma tenofovir concentrations. We aimed to further assess safety and efficacy of fixed-dose combination emtricitabine with tenofovir alafenamide in patients switched from emtricitabine with tenofovir disoproxil fumarate.

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Moulin-Frier et al. (2016) proffer a conceptual framework and computational modeling architecture for the investigation of the emergence of phonological universals for spoken languages. They validate the framework and architecture by testing to see whether universals such as the prevalence of triangular vowel systems that show adequate dispersion in the F1-F2-F3 space can fall out of simulations of referential communication between social agents, without building principles such as dispersion directly into the model.

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Background: Antiretroviral regimens containing tenofovir disoproxil fumarate have been associated with renal toxicity and reduced bone mineral density. Tenofovir alafenamide is a novel tenofovir prodrug that reduces tenofovir plasma concentrations by 90%, thereby decreasing off-target side-effects. We aimed to assess whether efficacy, safety, and tolerability were non-inferior in patients switched to a regimen containing tenofovir alafenamide versus in those remaining on one containing tenofovir disoproxil fumarate.

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Background: Tenofovir disoproxil fumarate can cause renal and bone toxic effects related to high plasma tenofovir concentrations. Tenofovir alafenamide is a novel tenofovir prodrug with a 90% reduction in plasma tenofovir concentrations. Tenofovir alafenamide-containing regimens can have improved renal and bone safety compared with tenofovir disoproxil fumarate-containing regimens.

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Objectives: Infrared thermal detection systems (ITDSs) have been used with limited success outside the United States to screen for fever during recent outbreaks of novel infectious diseases. Although ITDSs are fairly accurate in detecting fever in adults, there is little information about their utility in children.

Methods: In a pediatric emergency department, we compared temperatures of children (<18 years old) measured using 3 ITDSs (OptoTherm Thermoscreen, FLIR ThermoVision 360, and Thermofocus 0800H3) to standard, age-appropriate temperature measurements (confirmed fever defined as ≥38.

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We report week 96 results from a phase 3 trial of elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate (EVG/COBI/FTC/TDF, n = 348) vs efavirenz/emtricitabine/tenofovir disoproxil fumarate (EFV/FTC/TDF, n = 352). At week 48, EVG/COBI/FTC/TDF was noninferior to EFV/FTC/TDF (88% vs 84%, difference +3.6%, 95% confidence interval: -1.

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This ongoing, randomized, double-blind, active-controlled phase 3 international trial demonstrated the noninferior efficacy of elvitegravir/cobicistat/emtricitabine/tenofovir DF (EVG/COBI/FTC/TDF) compared with atazanavir boosted by ritonavir (ATV/RTV) plus emtricitabine/tenofovir disoproxil fumarate (FTC/TDF) at 48 weeks. Here, we report the week 96 results. Of 708 treated subjects, virological success (Food and Drug Administration snapshot) was maintained at week 96 with EVG/COBI/FTC/TDF and ATV/RTV + FTC/TDF (83% vs 82%, difference 1.

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The effects of influenza on a population are attributable to the clinical severity of illness and the number of persons infected, which can vary greatly between seasons or pandemics. To create a systematic framework for assessing the public health effects of an emerging pandemic, we reviewed data from past influenza seasons and pandemics to characterize severity and transmissibility (based on ranges of these measures in the United States) and outlined a formal assessment of the potential effects of a novel virus. The assessment was divided into 2 periods.

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A systematic study of nanoenergetic films consisting of nanostructured porous silicon impregnated with sodium perchlorate is carried out. The explosive properties of these films are investigated as a function of thickness, porosity, and confinement. The films' burning rates are investigated using fiber-optic velocity probes, demonstrating that flame-front velocities vary between approximately 1 and 500 m s(-1) and are very sensitive to the films' structural characteristics.

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