Comparisons of Aerosol Generation Across Different Musical Instruments and Loudness

Highlights•Aerosol number and mass concentrations measured during musical instrument playing.•A 1 dBA increase in sound pressure level yields ∼10% increase in number concentration.•Loudness of playing explains some but not all differences across instruments.•Musical instrument playing size distributions are consistent with those of breathing.•Simple songs sufficient to characterise aerosol emission during actual performance.AbstractRespiratory aerosols can serve as vectors for disease transmission, and aerosol emission is highly activity-dependent. COVID-19 severely impacted the performing arts due to concerns about disease spread by respiratory aerosols and droplets generated during singing and playing musical instruments. Aerosol generation from woodwind and brass performance is less understood compared to singing due to uncertainty about how the diverse range of musical instruments may impact respiratory aerosol concentrations and size distributions. Here, aerosol number and mass concentrations along with size distributions were measured for breathing, speaking, and playing four different woodwind and brass instruments by 23 professional instrumentalists. We find that a 1 dBA increase in sound pressure level corresponds to a ∼10% increase in aerosol number concentration. The aerosol size distribution is consistent with that of breathing. Differences in aerosol emission across musical instruments can be partly explained by the loudness of performance. Measuring aerosol generation from single notes or simple songs may be sufficient to characterise the aerosol emission range during actual performance, provided a range of loudnesses are accessed. These results provide insight into the factors contributing to aerosol emission during musical performance and facilitate risk assessments associated with infectious respiratory disease transmission in the performing arts

The Microphysics of Surrogates of Exhaled Aerosols from the Upper Respiratory Tract

Airborne transmission plays a significant role in the transmission of respiratory diseases such as COVID-19, for which the respiratory aerosol droplets are responsible for the transportation of potentially infectious pathogens. However, the aerosol physicochemical dynamics during the exhalation process are not well understood. The representativeness of respiratory droplet surrogates of exhaled aerosol and suspension media for aerosols currently used for laboratory studies remains debated. Here, we compare the evaporation kinetics and equilibrium thermodynamics of surrogate respiratory aerosol droplets including sodium chloride, artificial saliva (AS) and Dulbecco’s modified Eagle’s medium (DMEM) by using the Comparative Kinetics Electrodynamic Balance. The potential influences of droplet composition on aerosol hygroscopic response and phase behaviour, and the influence of mucin are reported. The equilibrium hygroscopicity measurement was used to verify and benchmark the prediction of evaporation kinetics of complex solutions using the Single Aerosol Particle Drying Kinetics and Trajectory model. We show that the compositionally complex culture media which differs from sodium chloride and artificial saliva (mucin-free solutions). The DMEM evaporation dynamics contained three distinctive phases when drying at a range of humidities, including a semi-dissolved phase when evaporating at the environmental humidity range. The effect of mucin on droplet evaporation and phase behaviour at low RH were compared between AS and DMEM solutions. In both cases, mucin delayed the crystallisation time of the droplets, but it promoted phase change (from homogenous to semi-dissolved/spherical with inclusions) to occur at higher water activities

Acceptability of Specialist Psychotherapy with Emotion for Anorexia in Kent and Sussex (SPEAKS):A novel intervention for anorexia nervosa

bjectiveInvestigate the acceptability of Specialist Psychotherapy with Emotion for Anorexia in Kent and Sussex (SPEAKS), a novel intervention for anorexia nervosa (AN), conducted as a feasibility trial to provide an initial test of the intervention.MethodsSPEAKS therapy lasting 9–12 months was provided to 34 people with AN or atypical AN by eight specialist eating disorder therapists trained in the model across two NHS Trusts in the UK (Kent and Sussex) during a feasibility trial. All participants were offered a post-therapy interview; sixteen patients and six therapists agreed. All patient participants were adult females. Interviews were semi-structured and asked questions around individuals' experience of SPEAKS, the acceptability of the intervention and of the research methods. Interviews were analyzed using thematic analysis.ResultsKey areas explored in line with research questions led to 5 overarching themes and 14 subthemes: (1) shift in treatment focus and experience, (2) balancing resources and treatment outcomes, (3) navigating the online treatment environment, (4) therapist adaptation and professional development, and (5) research processes.DiscussionSPEAKS was found to be an acceptable intervention for treating AN from the perspective of patients and therapists. The findings provide strong support for delivery of a larger scale randomized control trial. Recommendations for future improvements, particularly pertaining to therapist understanding of the treatment model are detailed, alongside broader clinical implications.Public SignificanceWe aimed to evaluate the acceptability of a new anorexia nervosa treatment called SPEAKS. Interviews were conducted with patients and therapists involved in the pilot study and responses were analyzed. Results showed that both patients and therapists found SPEAKS to be an acceptable treatment for anorexia nervosa. The study suggests that SPEAKS meets the criteria for moving forward with a larger trial to assess its effectiveness

Finite element modelling strategy for determining directivity of thermoelastically generated laser ultrasound

Laser ultrasound (LU) is a contactless and couplant-free remote non-destructive (NDE) technique, which uses lasers for ultrasonic generation and detection rather than conventional piezoelectric transducers. For a transducer, an important characteristic is the directivity, the angle-dependent amplitude of the ultrasonic waves generated in the material. In the non-destructive thermoelastic regime, LU source has been widely modelled as a surface force dipole. However, the directivity of LU in more complex material, where there is an increasing demand for NDE, such as carbon fibre reinforced plastic (CFRP), is yet to be understood. In the current paper, a finite element (FE) modelling methodology to obtain the directivity of LU in complex material is presented. The method is applied to a conductive isotropic material (aluminium, Al) for validation against an existing analytical solution and then applied to a heterogeneous anisotropic material (carbon-fibre reinforced plastic, CFRP). To get the directivity of a specific wave mode, the signal for that mode needs to be resolved in time from other modes at all angles. This is challenging for shear (S) waves in a small model domain due to the head wave, so a technique for suppressing the head wave is shown. The multi-physics model solves for thermal expansion, which models the laser source as a surface heat flux for the Al case, and a buried heat source for the CFRP case, according to where the energy is deposited in the material. The same ultrasound generation pattern can be obtained by using a suitable pure elastodynamic loading, which is shown to be a surface force dipole as per the validation case for Al, and a buried quadrupole for the CFRP case. The modelled directivities are scaled and fitted to experimental measurements using maximum likelihood, and the goodness of fit is discussed. For the Al case, the S wave is preferred over the longitudinal (L) wave for inspection due to greater signal amplitude. For the CFRP case, the quasi-longitudinal (qL) wave in CFRP shows a maximum amplitude directly below the source, and has a greater amplitude than the quasi-shear (qS) wave, suggesting a better choice for inspection

A qualitative exploration of the barriers and facilitators of community pharmacy PrEP delivery for pharmacists and community members

BACKGROUNDOral Pre-Exposure Prophylaxis (PrEP) is only available free of charge in the United Kingdom from sexual health clinics. Expanding PrEP delivery to community pharmacies could be an effective way of improving access to PrEP and aligns well with the UK government goals for England to eliminate new cases of HIV by 2030. Using the Capability, Opportunity, Motivation, Behaviour (COM-B) Model, the aim of this research was to explore the barriers and facilitators of community pharmacy PrEP delivery, perceived by pharmacists and community members underserved through current delivery models.METHODCommunity members at risk of acquiring HIV but not currently accessing PrEP and community pharmacists were recruited to participate in semi-structured open-ended interviews. Interviews were online, via phone or in person, were audio recorded, fully transcribed, and analysed using thematic analysis, informed by COM-B. RESULTSA total of 17 interviews with pharmacists (pharmacy owners n=7; employed pharmacists n=6; locums n=4) and 24 with community members (Black African women n=6; other women n=2; young adults aged 18- 25-years n=6; trans people n=6; street sex workers n=4) were conducted. Thematic analysis showed barriers include sub-optimal awareness and knowledge of PrEP, perceptions of pharmacist roles in delivering public health services (capability), lack of staff capacity, pharmacy facilities and privacy (opportunity), concern about being seen accessing PrEP from a pharmacy, a preference to access PrEP from a General Practitioner (GP) and a belief that pharmacy PrEP delivery could increase STIs (motivation). Facilitators included improving PrEP education and awareness (capability), the accessibility of pharmacies, being able to deliver PrEP via a patient group directive (PGD) (opportunity), a general preference for pharmacy PrEP and a belief that this model of delivery would be discrete, help decrease stigma and improve access to PrEP, particularly for those who felt uncomfortable accessing PrEP from sexual health clinics (motivation). CONCLUSIONPharmacy PrEP delivery is acceptable to pharmacists and community members but for it to be feasible, results point to the need for a behaviour change intervention incorporating education, training and awareness raising, for both pharmacists and community members to improve access, stimulate patient activation and de-stigmatise HIV and PrEP. <br/

Gaza in plain sight:witnessing in solidarity

In this visual essay, Mazen Kerbaj and Jana Traboulsi bear witness to the genocidal violence that has been unfolding in Gaza since 7 October 2023. From Berlin and Lebanon, respectively, Kerbaj and Traboulsi have been chronicling and responding to the harrowing day-to-day news and testimonies from Gaza. Their drawings raise fundamental questions about what it is to bear witness to genocide as it unfolds, about the politics of seeing as an act of solidarity against imposed invisibility and about racialized sight – the eye that refuses to see what is hiding in plain sight