922017 research outputs found
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Flexible sensors, circuits, and systems for bioelectronic interfacing
No full textBioelectronics is an emerging research area where human-made electronic systems interface, bidirectionally, with the electrical systems present in biology. Flexible electronics are a critical development for bioelectronic systems which can flex and stretch with the body. Printing based manufacturing approaches have been heavily investigated in recent years for creating bioelectronic systems, as screen printing can potentially provide scaled-up roll-to-roll based manufacturing while 3D and inkjet printing can potentially provide opportunities for personalisation. This paper presents a brief narrative review bioelectronics, the materials challenges in flexible sensors, circuits, and systems for bioelectronic interfacing, and examples of our approaches to tackling these challenges
Loneliness, Social Isolation, and Healthcare Utilization in the General Population
No full textObjectives Due to increasing pressure on healthcare resources, knowledge of factors that affect healthcare utilization (HCU) is important. However, the evidence of a longitudinal association between loneliness and social isolation respectively, and HCU is limited. The present prospective cohort study investigated the association of loneliness and social isolation with HCU in the general population over time. Methods Data from the 2013 Danish “How are you?" survey (n = 27.501) were combined with individual-level register data with almost complete follow-up over a 6-year follow-up period (2013-2018). Negative binomial regression analyses were performed while adjusting for baseline demographics and pre-existing chronic disease. Results Loneliness measured was significantly associated with more general practice contacts (incident-rate ratio (IRR) = 1.03, 95% confidence interval (CI) [1.02, 1.04]), more emergency treatments (IRR = 1.06, 95% CI [1.03, 1.10]), more emergency admissions (IRR = 1.06, 95% CI [1.03, 1.06]), and hospital admission days (IRR=1.05, 95% CI [1.00, 1.11]) across the 6-year follow-up period. No significant associations were found between social isolation and HCU with one minor exception, in which social isolation was associated with fewer planned outpatient treatments (IRR = .97, 95% CI [.94, .99]). Wald test demonstrated that the association of loneliness with emergency admissions and hospital admissions days was not significantly different from the effects of social isolation on those outcomes. Conclusions Our findings suggest that loneliness slightly increased the number of general practice contacts and emergency room treatments. Overall, the effects of loneliness and social isolation on HCU were small
Antiplatelet resistance: a review of concepts, mechanisms and implications for management in acute ischaemic stroke and transient ischaemic attack
No full textAcute ischaemic stroke is a leading cause of death and major disability worldwide. Approximately 50% of ischaemic strokes are caused by atherothrombotic occlusion of the cerebral arteries and antiplatelets are the mainstay of secondary stroke preventative treatment. Aspirin is beneficial if given early and short-term treatment using aspirin and clopidogrel is increasingly used for patients with intracranial atherosclerotic disease, minor stroke and/or transient ischemic attack. However, up to 50% of patients continue to have recurrent stroke and major vascular events, which may be partly due to resistance to aspirin and/or clopidogrel. Although the precise mechanisms are unknown, clinical and genetic factors associated with bioavailability and binding to target receptors are implicated. This narrative review begins with the concept of aspirin and clopidogrel resistance in ischaemic stroke and transient ischaemic attack (TIA), potential mechanisms including genetic polymorphisms and an overview of platelet function measures and limitations. We conclude by highlighting practical issues in the management of patients with aspirin and/or clopidogrel resistance including the emerging interest in ticagrelor, prasugrel and cilostazol and directions for future trials in TIA and acute ischaemic stroke
Second coordination sphere effects on the mechanistic pathways for dioxygen activation by a ferritin: involvement of a Tyr radical and the identification of a cation binding site
No full textFerritins are ubiquitous diiron enzymes involved in iron(II) detoxification and oxidative stress responses and can act as metabolic iron stores. The overall reaction mechanisms of ferritin enzymes are still unclear, particularly concerning the role of the conserved, near catalytic center Tyr residue. Thus, we carried out a computational study of a ferritin using a large cluster model of well over 300 atoms including its first- and second-coordination sphere. The calculations reveal important insight into the structure and reactivity of ferritins. Specifically, the active site Tyr residue delivers a proton and electron in the catalytic cycle prior to iron(II) oxidation. In addition, the calculations highlight a likely cation binding site at Asp65, which through long-range electrostatic interactions, influences the electronic configuration and charge distributions of the metal center. The results are consistent with experimental observations but reveal novel detail of early mechanistic steps that lead to an unusual mixedvalent iron(III)-iron(II) center
Do we need audiogram-based prescriptions? A systematic review.
No full textOBJECTIVE: Hearing aids are typically programmed using the individual’s audiometric thresholds and verified using real-ear measures. Developments in technology have resulted in a new category of direct-to-consumer devices, which are not necessarily programmed using the individual’s audiometric thresholds. This review aimed to identify whether programming hearing aids using the individual’s validated audiogram-based prescription, and verified using real-ear measures, results in better outcomes for adults with hearing loss.DESIGN: The review was registered in PROSPERO and reported in accordance with PRISMA guidelines.STUDY SAMPLE: After screening more than 1,370 records, seven experimental studies met the eligibility criteria.RESULTS: Studies were categorised under three methods of fitting: (i) comparative fitting evaluating different settings based on the beliefs of the audiologist; (ii) client choice of preset responses; and (iii) self-fit by adjustment. The findings suggest that using a prescription based on the individual’s audiogram improves outcomes relative to the comparative and client choice fitting approaches. Self-adjustment during daily use may produce equivalent (or better) outcomes than an audiogram-based prescription. The quality of evidence for the outcomes ranged from low to very low. CONCLUSIONS: This review has highlighted the dearth of high-quality studies on which to make evidence-based decisions on hearing aid fitting methods. <br/
Combined statistical decision limits based on two GH-2000 scores for the detection of growth hormone misuse
No full textThe GH-2000 biomarker method, based on the measurements of insulin-like growth factor-I (IGF-I) and the amino-terminal pro-peptide of type III collagen (P-III-NP), has been developed as a powerful technique for the detection of growth hormone (GH) misuse by athletes. IGF-I and P-III-NP are combined in gender specific formulas to create the GH-2000 score, which is used to determine whether GH has been administered. To comply with World Anti-Doping Agency regulations, each analyte must be measured by two methods. IGF-I and P-III-NP can be measured by a number of approved methods, each leading to its own GH-2000 score. Single decision limits for each GH-2000 score have been introduced and developed by Bassett, Erotokritou-Mulligan, Holt, Boehning and their co-authors in a series of papers. These have been incorporated into the guidelines of the World Anti-Doping Agency. A joint decision limit was constructed based on the sample correlation between the two GH-2000 scores generated from an available sample in order to increase the sensitivity of the biomarker method. This paper takes this idea further into a fully developed statistical approach. It constructs combined decision limits when two GH-2000 scores from different assay combinations are used to decide whether an athlete has been misusing GH. The combined decision limits are directly related to tolerance regions and constructed using a Bayesian approach. It is also shown to have highly satisfactory frequentist properties. The new approach meets the required false-positive rate with a pre-specified level of certainty
First discoveries and localisations of Fast Radio Bursts with MeerTRAP: a real-time, commensal MeerKAT survey
No full textWe report on the discovery and localization of fast radio bursts (FRBs) from the MeerTRAP project, a commensal fast radiotransient-detection programme at MeerKAT in South Africa. Our hybrid approach combines a coherent search with an averagefield-of-view of 0.4 deg2 with an incoherent search utilizing a field-of-view of 1.27 deg2 (both at 1284 MHz). Here, wepresent results on the first three FRBs: FRB 20200413A (DM=1990.05 pc cm􀀀3), FRB 20200915A (DM=740.65 pc cm􀀀3),and FRB 20201123A (DM=433.55 pc cm􀀀3). FRB 20200413A was discovered only in the incoherent beam. FRB 20200915A(also discovered only in the incoherent beam) shows speckled emission in the dynamic spectrum which cannot be explained byinterstellar scintillation in our Galaxy or plasma lensing, and might be intrinsic to the source. FRB 20201123A shows a faintpost-cursor burst about 200 ms after the main burst and warrants further follow-up to confirm whether it is a repeating FRB.FRB 20201123A also exhibits significant temporal broadening consistent with scattering by a turbulent medium. The broadeningexceeds that predicted for medium along the sightline through our Galaxy.We associate this scattering with the turbulent mediumin the environment of the FRB in the host galaxy. Within the approximately 10 localization region of FRB 20201123A , weidentify one luminous galaxy (A 15•67; J173438.35􀀀504550.4) that dominates the posterior probability for a host association.The galaxy’s measured properties are consistent with other FRB hosts with secure associations
Embodied Attention in Word-Object Mapping: A Developmental Cognitive Robotics Model
No full textDevelopmental Robotics models provide useful tools to study and understand the language learning process in infants and robots. These models allow us to describe key mechanisms of language development, such as statistical learning, the role of embodiment, and the impact of the attention payed to an object while learning its name. Robots can be particularly well suited for this type of problems, because they cover both a physical manipulation of the environment and mathematical modeling of the temporal changes of the learned concepts. In this work we present a computational representation of the impact of embodiment and attention on word learning, relying on sensory data collected with a real robotic agent in a real world scenario. Results show that the cognitive architecture designed for this scenario is able to capture the changes underlying the moving object in the field of view of the robot. The architecture successfully handles the temporal relationship in moving items and manages to show the effects of the embodied attention on word-object mapping
Efficient Approximation of Expected Hypervolume Improvement using Gauss-Hermite Quadrature
No full textMany methods for performing multi-objective optimisation of computationally expensive problems have been proposed recently. Typically, a probabilistic surrogate for each objective is constructed from an initial dataset. The surrogates can then be used to produce predictive densities in the objective space for any solution. Using the predictive densities, we can compute the expected hypervolume improvement (EHVI) due to a solution. Maximising the EHVI, we can locate the most promising solution that may be expensively evaluated next. There are closed-form expressions for computing the EHVI, integrating over the multivariate predictive densities. However, they require partitioning the objective space, which can be prohibitively expensive for more than three objectives. Furthermore, there are no closed-form expressions for a problem where the predictive densities are dependent, capturing the correlationsbetween objectives. Monte Carlo approximation is used instead in such cases, which is not cheap. Hence, the need to develop new accurate but cheaper approximation methods remains. Here we investigate an alternative approach toward approximating the EHVI using Gauss-Hermite quadrature.We show that it can be an accurate alternative to Monte Carlo for both independent and correlated predictive densities with statistically signicant rank correlations for a range of popular test problems