Estimating the incidence of COVID-19, influenza and respiratory syncytial virus infection in three regions of Queensland, Australia, winter 2022: findings from a novel longitudinal testing-based sentinel surveillance programme.

OBJECTIVE: The 2022 Australian winter was the first time that COVID-19, influenza and respiratory syncytial virus (RSV) were circulating in the population together, after two winters of physical distancing, quarantine and borders closed to international travellers. We developed a novel surveillance system to estimate the incidence of COVID-19, influenza and RSV in three regions of Queensland, Australia. DESIGN: We implemented a longitudinal testing-based sentinel surveillance programme. Participants were provided with self-collection nasal swabs to be dropped off at a safe location at their workplace each week. Swabs were tested for SARS-CoV-2 by PCR. Symptomatic participants attended COVID-19 respiratory clinics to be tested by multiplex PCR for SARS-CoV-2, influenza A and B and RSV. Rapid antigen test (RAT) results reported by participants were included in the analysis. SETTING AND PARTICIPANTS: Between 4 April 2022 and 3 October 2022, 578 adults were recruited via their workplace. Due to rolling recruitment, withdrawals and completion due to positive COVID-19 results, the maximum number enrolled in any week was 423 people. RESULTS: A total of 4290 tests were included. Participation rates varied across the period ranging from 25.9% to 72.1% of enrolled participants. The total positivity of COVID-19 was 3.3%, with few influenza or RSV cases detected. Widespread use of RAT may have resulted in few symptomatic participants attending respiratory clinics. The weekly positivity rate of SARS-CoV-2 detected during the programme correlated with the incidence of notified cases in the corresponding communities. CONCLUSION: This testing-based surveillance programme could estimate disease trends and be a useful tool in settings where testing is less common or accessible. Difficulties with recruitment meant the study was underpowered. The frontline sentinel nature of workplaces meant participants were not representative of the general population but were high-risk groups providing early warning of disease.

The Resurgence of Lymphogranuloma Venereum: Changing Presentation of Lymphogranuloma Venereum in the Era of HIV Preexposure Prophylaxis, 2004 to 2022.

BACKGROUND: Before the early 2000s, the sexually transmitted infection lymphogranuloma venereum (LGV) was rare in high-income countries. Initially, most cases in these countries were among symptomatic men who have sex with men (MSM) living with HIV. In the context of widespread HIV preexposure prophylaxis (PrEP), LGV's epidemiology may be changing. We aimed to characterize the epidemiology and clinical presentation of LGV in the PrEP era. METHODS: A retrospective chart review was performed on all LGV cases occurring between November 2004 to October 2022 in British Columbia (BC), Canada. Cases were stratified by having occurred before (2004-2017) or after widespread PrEP availability in BC (2018-2022). Annual rates and test positivity percentages were calculated. Bivariate logistic regression was performed to identify drivers of asymptomatic infection in the PrEP era. RESULTS: Among 545 cases identified, 205 (37.6%) occurred pre-PrEP and 340 (62.4%) occurred during the PrEP era. Most cases were among MSM (97.2%). The estimated rate of LGV has doubled from 2018 to 2022, reaching 1535.2 cases per 100,000 PrEP users. Most PrEP-era cases were among HIV-negative individuals (65.3%), particularly those on PrEP (72.6%). Cases in the PrEP era were often asymptomatic compared with pre-PrEP (38.6% vs. 19.3%; P < 0.001). Users of PrEP were more likely to experience asymptomatic infection compared with HIV-negative PrEP nonusers (odds ratio, 2.07; 95% confidence interval, 1.07-3.99). CONCLUSIONS: In the context of increased asymptomatic testing, LGV may be increasing in BC. Most infections now occur among HIV-negative MSM. A high proportion of infections are asymptomatic.

Collective chemomechanical oscillations in active hydrogels.

We report on the collective response of an assembly of chemomechanical Belousov-Zhabotinsky (BZ) hydrogel beads. We first demonstrate that a single isolated spherical BZ hydrogel bead with a radius below a critical value does not oscillate, whereas an assembly of the same BZ hydrogel beads presents chemical oscillation. A BZ chemical model with an additional flux of chemicals out of the BZ hydrogel captures the experimentally observed transition from oxidized nonoscillating to oscillating BZ hydrogels and shows this transition is due to a flux of inhibitors out of the BZ hydrogel. The model also captures the role of neighboring BZ hydrogel beads in decreasing the critical size for an assembly of BZ hydrogel beads to oscillate. We finally leverage the quorum sensing behavior of the collective to trigger their chemomechanical oscillation and discuss how this collective effect can be used to enhance the oscillatory strain of these active BZ hydrogels. These findings could help guide the eventual fabrication of a swarm of autonomous, communicating, and motile hydrogels.

Protocol for a winter sentinel surveillance program of notifiable respiratory viruses in Queensland.

BACKGROUND: With the reduction in access to polymerase chain reaction (PCR) testing and changes in testing guidelines in Australia, a reduced number of people are seeking testing for coronavirus disease (COVID-19), limiting the opportunity to monitor disease transmission. Knowledge of community transmission of COVID-19 and other respiratory viruses is essential to better predict subsequent surges in cases during the pandemic to alert health services, protect vulnerable populations and enhance public health measures. We describe a methodology for a testing-based sentinel surveillance program to monitor disease in the community for early signal detection of SARS-CoV-2 and other respiratory viruses. METHODS/DESIGN: A longitudinal active testing-based sentinel surveillance program for respiratory viruses (including SARS-CoV-2, influenza A, influenza B and Respiratory Syncytial Virus) will be implemented in some regions of Queensland. Adults will be eligible for enrolment if they are part of specific community groups at increased risk of exposure and have not had a COVID-19 infection in the last 13 weeks. Recruitment via workplaces will occur in-person, via email and through online advertisement. Asymptomatic participants will be tested via PCR for SARS-CoV-2 infection by weekly self-collected nasal swabs. In addition, symptomatic participants will be asked to seek SARS-CoV-2 and additional respiratory virus PCR testing at nominated COVID-19 testing sites. SARS-CoV-2 and respiratory virus prevalence data will be analysed weekly and at the end of the study period. DISCUSSION: Once implemented, this surveillance program will determine the weekly prevalence of COVID-19 and other respiratory viruses in the broader community by testing a representative sample of adults, with an aim to detect early changes in the baseline positivity rate. This information is essential to define the epidemiology of SARS-CoV-2 in the community in near-real time to inform public health control measures and prepare health services and other stakeholders for a rise in service demand.

Comparing medical student experience of face-to-face and remote access consultations during the coronavirus pandemic.

INTRODUCTION: As a result of the coronavirus pandemic, outpatient consultations in National Health Service Lanarkshire were conducted using various forms of teleconsultation. A qualitative study was undertaken to ascertain how senior medical students valued the experience of outpatient teleconsultations in comparison to face-to-face consultations during the pandemic. METHODS: Anonymised, voluntary surveys were emailed to all medical students who attended clinical placements in specialties utilising teleconsultations. Participants were asked to compare their experience of and perceived value of virtual consultants to face-to-face consultations. Thematic and statistical analysis was performed on the collected data. RESULTS: Participants unanimously agreed face-to-face consultations enabled learning, with 71.4% (n = 7) having similar experiences in video consultations if a senior was physically present beside them. Video consultation, when the senior clinician was also present virtually, was deemed useful to a lesser extent (66.7%, n = 6). Only half (57.1%, n = 14) valued the learning from telephone consultations. Qualitative analysis revealed that although face to face was the preferred consultation style, there was useful learning gained in all modalities. Students appreciated discussion with senior clinicians to facilitate learning and valued involvement in the consultation through history taking, especially in teleconsultations. DISCUSSION: Teleconsultation was an effective learning tool for medical students during the coronavirus pandemic, which preserved student exposure to patients during lockdown. This study is optimistic that widespread incorporation of teleconsultation, in all modality, has the ability to support students' clinical exposure and learning, which is becoming increasingly limited as medical student numbers continue to rise and with the ongoing effects of the pandemic.

Pattern formation in a four-ring reaction-diffusion network with heterogeneity.

In networks of nonlinear oscillators, symmetries place hard constraints on the system that can be exploited to predict universal dynamical features and steady states, providing a rare generic organizing principle for far-from-equilibrium systems. However, the robustness of this class of theories to symmetry-disrupting imperfections is untested in free-running (i.e., non-computer-controlled) systems. Here, we develop a model experimental reaction-diffusion network of chemical oscillators to test applications of the theory of dynamical systems with symmeries in the context of self-organizing systems relevant to biology and soft robotics. The network is a ring of four microreactors containing the oscillatory Belousov-Zhabotinsky reaction coupled to nearest neighbors via diffusion. Assuming homogeneity across the oscillators, theory predicts four categories of stable spatiotemporal phase-locked periodic states and four categories of invariant manifolds that guide and structure transitions between phase-locked states. In our experiments, we observed that three of the four phase-locked states were displaced from their idealized positions and, in the ensemble of measurements, appeared as clusters of different shapes and sizes, and that one of the predicted states was absent. We also observed the predicted symmetry-derived synchronous clustered transients that occur when the dynamical trajectories coincide with invariant manifolds. Quantitative agreement between experiment and numerical simulations is found by accounting for the small amount of experimentally determined heterogeneity in intrinsic frequency. We further elucidate how different patterns of heterogeneity impact each attractor differently through a bifurcation analysis. We show that examining bifurcations along invariant manifolds provides a general framework for developing intuition about how chemical-specific dynamics interact with topology in the presence of heterogeneity that can be applied to other oscillators in other topologies.

Auto-Exposure Algorithm for Enhanced Mobile Robot Localization in Challenging Light Conditions.

The success of robot localization based on visual odometry (VO) largely depends on the quality of the acquired images. In challenging light conditions, specialized auto-exposure (AE) algorithms that purposely select camera exposure time and gain to maximize the image information can therefore greatly improve localization performance. In this work, an AE algorithm is introduced which, unlike existing algorithms, fully leverages the camera's photometric response function to accurately predict the optimal exposure of future frames. It also features feedback that compensates for prediction inaccuracies due to image saturation and explicitly balances motion blur and image noise effects. For validation, stereo cameras mounted on a custom-built motion table allow different AE algorithms to be benchmarked on the same repeated reference trajectory using the stereo implementation of ORB-SLAM3. Experimental evidence shows that (1) the gradient information metric appropriately serves as a proxy of indirect/feature-based VO performance; (2) the proposed prediction model based on simulated exposure changes is more accurate than using γ transformations; and (3) the overall accuracy of the estimated trajectory achieved using the proposed algorithm equals or surpasses classic exposure control approaches. The source code of the algorithm and all datasets used in this work are shared openly with the robotics community.

Shoulder Joint Stiffness in a Functional Posture at Various Levels of Muscle Activation.

OBJECTIVE: In this study, we present a method to quantify the mechanics of the shoulder joint in a functional posture, in two degrees of freedom: internal/external rotation and horizontal abduction/adduction. METHODS: We performed experiments on 15 healthy participants using a custom perturbation robot. Perturbations were applied in internal/external rotation and horizontal abduction/adduction, whilst participants applied varying levels of joint torque. System identification techniques were used to quantify the mechanical properties of the shoulder joint at various levels of muscle contraction, including; stiffness, viscous damping, and inertia parameters, natural frequency, and damping parameter. We compared the shoulder mechanical properties between dominant and non-dominant limbs. RESULTS: The mean stiffness increased 4.8 times in external rotation, and 6.25 times in internal rotation as a result of contraction to 8 Nm. It increased 2.8 times in adduction and 4.6 times in abduction as a result of contraction to 16 Nm. The mean viscous damping increased 3 times in external rotation, 2.8 times in internal rotation as a result of contraction to 8 Nm. It increased 1.6 times in adduction and 2.25 times in abduction as a result of contraction to 16 Nm. CONCLUSION: Joint stiffness, viscous damping and natural frequency all increased with the level of shoulder contraction torque, whereas the damping parameter remained unchanged. No differences were observed between dominant and non-dominant limbs. SIGNIFICANCE: We have presented a method to characterize the mechanical properties of the shoulder complex during various activation states, which has application as a diagnostic and assessment tool for shoulder pathology.

Impact of a microfluidic jet on a pendant droplet.

High speed microfluidic jets can be generated by a thermocavitation process: from the evaporation of the liquid inside a microfluidic channel, a rapidly expanding bubble is formed and generates a jet through a flow focusing effect. Here, we study the impact and traversing of such jets on a pendant liquid droplet. Upon impact, an expanding cavity is created, and, above a critical impact velocity, the jet traverses the entire droplet. We predict the critical traversing velocity (i) from a simple energy balance and (ii) by comparing the Young-Laplace and dynamic pressures in the cavity that is created during the impact. We contrast the model predictions against experiments, in which we vary the liquid properties of the pendant droplet and find good agreement. In addition, we assess how surfactants and viscoelastic effects influence the critical impact velocity. Our results increase the knowledge of the jet interaction with materials of well-known physical properties.

Impact of PDMS-Based Microfluidics on Belousov-Zhabotinsky Chemical Oscillators.

Sub-nanoliter volumes of the Belousov-Zhabotinsky (BZ) reaction are sealed in microfluidic devices made from polydimethylsiloxane (PDMS). Bromine, which is a BZ reaction intermediate that participates in the inhibitory pathway of the reaction, is known to permeate into PDMS, and it has been suggested that PDMS and bromine can react ( J. Phys. Chem. A. 108, 2004, 1325-1332). We characterize the extent to which PDMS affects BZ oscillations by varying the volume of the PDMS surrounding the BZ reactors. We measure how the oscillation period varies with PDMS volume and compare with a theoretical reaction-diffusion model, concluding that bromine reacts with PDMS. We demonstrate that minimizing the amount of PDMS by making the samples as thin as possible maximizes the number of oscillations before the BZ reaction reaches equilibrium and ceases to oscillate. We also demonstrate that the deleterious effects of the PDMS-BZ interactions are somewhat mitigated by imposing constant chemical boundary conditions through using a light-sensitive catalyst, ruthenium, in combination with patterned illumination. Furthermore, we show that light can modulate the frequency and phase of the BZ oscillators contained in a PDMS matrix by 20-30%.

Actuation of untethered pneumatic artificial muscles and soft robots using magnetically induced liquid-to-gas phase transitions.

Pneumatic artificial muscles have been widely used in industry because of their simple and relatively high-performance design. The emerging field of soft robotics has also been using pneumatic actuation mechanisms since its formation. However, these actuators/soft robots often require bulky peripheral components to operate. Here, we report a simple mechanism and design for actuating pneumatic artificial muscles and soft robotic grippers without the use of compressors, valves, or pressurized gas tanks. The actuation mechanism involves a magnetically induced liquid-to-gas phase transition of a liquid that assists the formation of pressure inside the artificial muscle. The volumetric expansion in the liquid-to-gas phase transition develops sufficient pressure inside the muscle for mechanical operations. We integrated this actuation mechanism into a McKibben-type artificial muscle and soft robotic arms. The untethered McKibben artificial muscle generated actuation strains of up to 20% (in 10 seconds) with associated work density of 40 kilojoules/meter3, which favorably compares with the peak strain and peak energy density of skeletal muscle. The untethered soft robotic arms demonstrated lifting objects with an input energy supply from only two Li-ion batteries.

Lessons learned: using adverse incident reports to investigate the characteristics and causes of prescribing errors.

INTRODUCTION: Prescribing errors are a principal cause of preventable harm in healthcare. This study aims to establish a systematic approach to analysing prescribing-related adverse incident reports, in order to elucidate the characteristics and contributing factors of common prescribing errors and target multifaceted quality improvement initiatives. METHODS: All prescribing-related adverse incident reports submitted across one NHS board over 12 months were selected. Incidents involving commonly implicated drugs (involved in ≥10 incidents) underwent analysis to establish likely underlying causes using Reason's Model of Accident Causation. RESULTS: 330 prescribing-related adverse incident reports were identified. Commonly implicated drugs were insulin (10% of incidents), gentamicin (7%), co-amoxiclav (5%) and amoxicillin (5%). The most prevalent error types were prescribing amoxicillin when contraindicated due to allergy (5%); prescribing co-amoxiclav when contraindicated due to allergy (5%); prescribing the incorrect type of insulin (3%); and omitting to prescribe insulin (3%). Error-producing factors were identified in 86% of incidents involving commonly implicated drugs. 53% of incidents involved error-producing factors related to the working environment; 38% involved factors related to the healthcare team; and 37% involved factors related to the prescriber. DISCUSSION: This study establishes that systematic analysis of adverse incident reports can efficiently identify the characteristics and contributing factors of common prescribing errors, in a manner useful for targeting quality improvement. Furthermore, this study produced a number of salient findings. First, a narrow range of drugs were implicated in the majority of incidents. Second, a small number of error types were highly recurrent. Lastly, a range of contributing factors were evident, with those related to the working environment contributing to the majority of prescribing errors analysed.

Dynamic Fluid-Like Graphene with Ultralow Frictional Molecular Bearing.

Fluid-like sliding graphenes but with solid-like out-of-plane compressive rigidity offer unique opportunities for achieving unusual physical and chemical properties for next-generation interfacial technologies. Of particular interest in the present study are graphenes with specific chemical functionalization that can predictably promote adhesion and wetting to substrate and ultralow frictional sliding structures. Lubricity between stainless steel (SS) and diamond-like carbon (DLC) is experimentally demonstrated with densely functionalized graphenes displaying dynamic intersheet bonds that mechanically transform into stable tribolayers. The macroscopic lubricity evolves through the formation of a thin film of an interconnected graphene matrix that provides a coefficient of friction (COF) of 0.01. Mechanical sliding generates complex folded graphene structures wherein equilibrated covalent chemical linkages impart rigidity and stability to the films examined in macroscopic friction tests. This new approach to frictional reduction has broad implications for manufacturing, transportation, and aerospace.

A novel microneedle device for controlled and reliable liquid biopsy of the human inner ear.

Sensorineural hearing loss is the most common sensory deficit worldwide, yet our understanding of the underlying pathophysiology is limited by the challenges of access to the inner ear in a safe and reliable manner. We present a novel microneedle device for trans-round window membrane liquid biopsy, which utilizes controlled depth of perforation and microliter aspiration control to safely biopsy fluids of the inner ear. Of eleven devices tested in fresh frozen human temporal bones, seven demonstrated alignment between electrical, visual and tactile detection of round window membrane perforation, and nine were successful in aspiration of meaningful diagnostic samples from the perilymphatic space. Purity of the average perilymph sample was 69% for a 5 µL sample volume, equivalent to 3.5 µL attributable to perilymph. Diagnostic success was shown both by transmastoid facial recess and transcanal tympanotomy approach. This device can enable new advances in the understanding of inner ear pathology, and brings us one step closer to liquid biopsy of the inner ear becoming a routine part of clinical care.

Elevated 20-HETE in metabolic syndrome regulates arterial stiffness and systolic hypertension via MMP12 activation.

Arterial stiffness plays a causal role in development of systolic hypertension. 20-hydroxyeicosatetraeonic acid (20-HETE), a cytochrome P450 (CYP450)-derived arachidonic acid metabolite, is known to be elevated in resistance arteries in hypertensive animal models and loosely associated with obesity in humans. However, the role of 20-HETE in the regulation of large artery remodeling in metabolic syndrome has not been investigated. We hypothesized that elevated 20-HETE in metabolic syndrome increases matrix metalloproteinase 12 (MMP12) activation leading to increased degradation of elastin, increased large artery stiffness and increased systolic blood pressure. 20-HETE production was increased ~7 fold in large, conduit arteries of metabolic syndrome (JCR:LA-cp, JCR) vs. normal Sprague-Dawley (SD) rats. This correlated with increased elastin degradation (~7 fold) and decreased arterial compliance (~75% JCR vs. SD). 20-HETE antagonists blocked elastin degradation in JCR rats concomitant with blocking MMP12 activation. 20-HETE antagonists normalized, and MMP12 inhibition (pharmacological and MMP12-shRNA-Lnv) significantly improved (~50% vs. untreated JCR) large artery compliance in JCR rats. 20-HETE antagonists also decreased systolic (182 ±â€¯3 mmHg JCR, 145 ±â€¯3 mmHg JCR + 20-HETE antagonists) but not diastolic blood pressure in JCR rats. Whereas diastolic pressure was fully angiotensin II (Ang II)-dependent, systolic pressure was only partially Ang II-dependent, and large artery stiffness was Ang II-independent. Thus, 20-HETE-dependent regulation of systolic blood pressure may be a unique feature of metabolic syndrome related to high 20-HETE production in large, conduit arteries, which results in increased large artery stiffness and systolic blood pressure. These findings may have implications for management of systolic hypertension in patients with metabolic syndrome.

Artificial Muscles: Mechanisms, Applications, and Challenges.

The area of artificial muscle is a highly interdisciplinary field of research that has evolved rapidly in the last 30 years. Recent advances in nanomaterial fabrication and characterization, specifically carbon nanotubes and nanowires, have had major contributions in the development of artificial muscles. However, what can artificial muscles really do for humans? This question is considered here by first examining nature's solutions to this design problem and then discussing the structure, actuation mechanism, applications, and limitations of recently developed artificial muscles, including highly oriented semicrystalline polymer fibers; nanocomposite actuators; twisted nanofiber yarns; thermally activated shape-memory alloys; ionic-polymer/metal composites; dielectric-elastomer actuators; conducting polymers; stimuli-responsive gels; piezoelectric, electrostrictive, magnetostrictive, and photostrictive actuators; photoexcited actuators; electrostatic actuators; and pneumatic actuators.

Needle-free small-volume liquid injection system powered by a rotary actuator.

Controllable jet injection could provide a fast, repeatable method for delivery of small volume, high viscosity drugs to the dermis. We have developed a compact, lightweight jet injector that uses a small commercial rotary motor and differential screw to create a jet of fluid with sufficient force to deliver drug into tissue. Clear tissue analogue and ex vivo tissue were used to demonstrate repeatable delivery of <;10 µL of fluid using the device. The fluid when forced through a narrow orifice (108 µm) reaches a velocity of >250 m/s with an injection time of <;3 ms.

High-speed X-ray analysis of liquid delivery during jet injection.

The effect of varying velocity during jet injection on the dispersion of fluid into tissue is investigated using a custom-built X-ray imaging system. Injections are performed into ex-vivo porcine abdominal tissue using a voice coil actuated injection device. Single velocity and two-phase velocity injections reveal the complex nature of the dispersion of the fluid jet in layered tissue and highlight the effects of changing the jet velocity following the initial penetration of the liquid into the tissue.

Ampoule and nozzle development for needle-free injections.

A rigid, compact, multi-piece ampoule has been designed and fabricated as a platform to conveniently house different nozzle inserts one at a time to offer increased jet consistency and functional flexibility. Three different nozzle geometries that respectively produce a single axial jet, radial jets, and intersecting jets are designed and fabricated. Through high-speed imaging and injection into tissue analog and ex vivo porcine tissue, these nozzles are demonstrated to have potential for a range of injection applications including intradermal, intratympanic, and traditional uses. The presented ampoule is more successful than a commercial jet injection ampoule in adhering to desired position and velocity trajectories and the energy efficiencies of jet ejections are compared.