Accurate Measurements and Simulations of the Evaporation and Trajectories of Individual Solution Droplets.

A refined numerical model for the evaporation and transport of droplets of binary solutions is introduced. Benchmarking is performed against other models found in the literature and experimental measurements of both electrodynamically trapped and freefalling droplets. The model presented represents the microphysical behavior of solutions droplets in the continuum and transition regimes, accounting for the unique hygroscopic behavior of different solutions, including the Fuchs-Sutugin and Cunningham slip correction factors, and accounting for the Kelvin effect. Simulations of pure water evaporation are experimentally validated for temperatures between 290 K and 298 K and between relative humidity values of approximately 0% and 85%. Measurements and simulations of the spatial trajectories and evaporative behavior of aqueous sodium chloride droplets are compared for relative humidity values between 0 and 40%. Simulations are shown to represent experimental data within experimental uncertainty in initial conditions. Calculations of a time-dependent Péclet number, including the temperature dependence of solute diffusion, are related to morphologies of sodium chloride particles dried at different rates. For sodium chloride solutions, dried particles are composed of collections of reproducibly shaped crystals, with higher evaporation rates resulting in higher numbers of crystals, which are smaller.

Effects of three chitin synthesis inhibitors on egg masses, nymphs and adults of Halyomorpha halys (Hemiptera: Pentatomidae).

BACKGROUND: Halyomorpha halys, (brown marmorated stink bug, BMSB), is a high-concern invasive species causing severe damage to orchards in many countries outside its native Asian range. Management methods other than frequent sprays of broad-spectrum insecticides are needed to restore integrated pest management (IPM) practices in orchards. Chitin synthesis inhibitors are usually regarded as desirable options in IPM programs because of lower toxicity to beneficial insects and non-target organisms compared to neurotoxic insecticides. In this study, the activity of three chitin synthesis inhibitors (namely buprofezin, novaluron and triflumuron) was investigated on BMSB egg masses, third instars and adults by means of laboratory bioassays. RESULTS: Novaluron and to a lesser extent triflumuron were detrimental to BMSB nymphs exposed to residues on potted peach plants. Novaluron caused high mortality among early instars that emerged from sprayed egg masses. No significant differences were found between buprofezin and water control on eggs or third instars. When sprayed on BMSB adults, none of the chitin synthesis inhibitors affected survival, fecundity, or egg hatching. CONCLUSION: Given the activity on nymphs, but the lack of effects on adults, novaluron and triflumuron might be considered for field applications only as a tool in a wider management strategy along with other methods aimed at preventing the invasion of crops by BMSB adults. © 2023 Society of Chemical Industry.

Dynamics and outcomes of binary collisions of equi-diameter picolitre droplets with identical viscosities.

The dynamics of binary collisions of equi-diameter picolitre droplets with identical viscosities, varying impact speeds and impact angles have been investigated experimentally and compared to collision outcome prediction models. Collisions between pairs of pure water droplets with a viscosity of 0.89 mPa s and pairs of aqueous-sucrose (40% w/w) droplets with a viscosity of 5.17 mPa s were examined. The colliding droplets were ∼38 µm in diameter, which is around ten times smaller than those previously investigated when examining the effect of viscosity on the outcome of binary droplet collisions. Varying the impact speed and angle resulted in different collision outcomes, including coalescence, reflexive separation and stretching separation. The collision outcomes were plotted on two viscosity dependent regime maps. The regime boundaries are generally in agreement with earlier literature for both high and low viscosity cases. The agreement between experiment and theory, for both fluids, gives more confidence in the models tested here to predict collision outcomes for droplets of this size and these viscosities.

Teledermatology Utilization and Integration in Residency Training Over the COVID-19 Pandemic.

BACKGROUND: During the 2019 Coronavirus (COVID-19) pandemic, the Division of Dermatology, University of Ottawa, adapted pre-existing local healthcare infrastructures to provide increased provider-to-provider teledermatology services as well as integrated teledermatology into the dermatology residency training program. OBJECTIVES: (1) To assess the differences in utilization of provider-to-provider teledermatology services before and during the COVID-19 pandemic; and (2) to assess dermatology resident and faculty experiences with the integration of teledermatology into dermatology residency training at the University of Ottawa. METHODS: We conducted a cross-sectional analysis comparing provider-to-provider teledermatology consults submitted to dermatologists from April 2019 to October 2019 pre-pandemic with the same period during the pandemic in 2020. Two different questionnaires were also disseminated to the dermatology residents and faculty at our institution inquiring about their perspectives on teledermatology, education, and practice. RESULTS: The number of dermatologists completing consults, the number of providers submitting a case to Dermatology, and the number of consults initiated all increased during the pandemic period. Ninety-one percent of residents agreed that eConsults and teledermatology enhanced their residency education, enabled continuation of training during the pandemic, and that eConsult-based training should be incorporated into the curriculum. Ninety-six percent of staff incorporated a virtual dermatology practice model, and one-third used teledermatology with residents during the pandemic. Most staff felt there was value in providing virtual visits in some capacity during the pandemic. CONCLUSIONS: Our study confirms that the use of teledermatology services continues to increase accessibility during the pandemic. Teledermatology enhances the education and training of residents and will be incorporated into dermatology residency programs.

Correction to "Accurate Representations of the Microphysical Processes Occurring during the Transport of Exhaled Aerosols and Droplets".

[This corrects the article DOI: 10.1021/acscentsci.0c01522.].

Accurate Representations of the Microphysical Processes Occurring during the Transport of Exhaled Aerosols and Droplets.

Aerosols and droplets from expiratory events play an integral role in transmitting pathogens such as SARS-CoV-2 from an infected individual to a susceptible host. However, there remain significant uncertainties in our understanding of the aerosol droplet microphysics occurring during drying and sedimentation and the effect on the sedimentation outcomes. Here, we apply a new treatment for the microphysical behavior of respiratory fluid droplets to a droplet evaporation/sedimentation model and assess the impact on sedimentation distance, time scale, and particle phase. Above a 100 µm initial diameter, the sedimentation outcome for a respiratory droplet is insensitive to composition and ambient conditions. Below 100 µm, and particularly below 80 µm, the increased settling time allows the exact nature of the evaporation process to play a significant role in influencing the sedimentation outcome. For this size range, an incorrect treatment of the droplet composition, or imprecise use of RH or temperature, can lead to large discrepancies in sedimentation distance (with representative values >1 m, >2 m, and >2 m, respectively). Additionally, a respiratory droplet is likely to undergo a phase change prior to sedimenting if initially <100 µm in diameter, provided that the RH is below the measured phase change RH. Calculations of the potential exposure versus distance from the infected source show that the volume fraction of the initial respiratory droplet distribution, in this size range, which remains elevated above 1 m decreases from 1 at 1 m to 0.125 at 2 m.

Optical Interrogation of Single Levitated Droplets in a Linear Quadrupole Trap by Cavity Ring-Down Spectroscopy.

Optical trapping is a well-established technique to manipulate and levitate micro- and nanoscale particles and droplets. However, optical traps for single aerosol studies are most often limited to trapping spherical nonabsorbing droplets, and a universal optical trap for the stable confinement of particles regardless of their absorption strength and morphology is not established. Instead, new opportunities arise from levitating droplets using electrodynamic traps. Here, using a combined electrodynamic linear quadrupole trap and a cavity ring-down spectrometer, we demonstrate that it is possible to trap single droplets and simultaneously measure their extinction cross sections and elastic scattering phase functions over extended periods of time. To test the novel setup, we evaluated the evaporation of 1,2,6-hexanetriol under low-humidity conditions, and the evolution of aqueous (NH4)2SO4 and NaCl droplets experiencing changing environmental conditions. Our studies extended beyond spherical droplets and we measured particle extinction cross sections after the efflorescence (crystallization) of the inorganic salt particles. Comparison of measured cross sections for crystallized particles with light scattering model predictions (using Mie theory or the T-matrix/extended boundary-condition method (EBCM) implementations for random orientation, with either the spheroid or superellipsoid parameterizations) enables information on particle shape to be inferred. Specifically, we find that cross sections for dry (NH4)2SO4 particles are accounted for by Mie theory and, thus, particle shape is represented well by a sphere. Conversely, the cross sections for dry NaCl particles are only reconciled with light scattering models pertaining to nonspherical shapes. These results will have implications for accurate remote sensing retrievals of dry salt optical properties and for parameterizations implemented in radiative forcing calculations with changing humidity. Moreover, our new platform for precise and accurate measurement of optical properties of micron-scale and sub-micron particles has potential applications in a range of areas of atmospheric science, such as precise light scattering measurements for ice crystals and mineral dust. It represents a promising step toward accurate characterizations of optical properties for nonspherical and light-absorbing aerosols.

Drying Kinetics and Particle Formation from Dilute Colloidal Suspensions in Aerosol Droplets.

Industrial processes such as spray drying of pharmaceutical and food products often involve the drying of aerosol droplets containing colloidal suspensions into powdered microparticles of desired properties. The morphology and surface properties of the final dry products/microparticles obtained after the drying process are strongly influenced by the parameters of the initial aerosol droplet composition and the drying conditions. In particular, the final dry microparticle morphology can be dependent on the dimensionless Péclet number (Pe), which expresses the relative competition between the diffusion of the dispersed particles within the droplet and the rate of solvent loss via evaporation. In this work, we examine how control over the gas phase drying conditions and initial aerosol droplet composition can be used to influence the aerosol droplet drying kinetics in the gas phase for a range of Péclet numbers. We used a single-particle levitation instrument, the electrodynamic balance, to measure the drying kinetics of colloidal silica droplets (0.10-0.60% v/v) under controlled gas phase drying conditions of temperature (263-326 K) and relative humidity (0-90%) and obtained Péclet numbers ranging from 4.05 to 184.5. We demonstrate that, for aerosol droplets with initially dilute feed colloid concentrations and within the constant evaporation regime, the starting composition does not strongly influence the solvent evaporation rate with the included nanoparticles (NPs) acting as spectators. However, the gas phase drying conditions, temperature, and relative humidity, directly influence the droplet temperature via evaporative cooling as well as the droplet drying kinetics and the final dry microparticle properties. With a priori knowledge of the droplet drying kinetics from the single droplet measurements, we further demonstrate the possibility of tailoring the morphology of the dried microparticles. Dried silica microparticles collected at Pe = 23.8 had dense spherical morphologies, while those at the highest Pe = 180.0 had crumpled surface morphologies with a transition in morphology between these limiting Pe values. Our results extend the fundamental understanding of the mechanisms controlling the drying of aerosol droplets in colloidal suspensions across a wide range of application areas extending from spray drying to the drying of respiratory fluid droplets containing bacteria and viruses and the drying of atmospheric aerosol droplets.

2019 update of EULAR recommendations for vaccination in adult patients with autoimmune inflammatory rheumatic diseases.

To update the European League Against Rheumatism (EULAR) recommendations for vaccination in adult patients with autoimmune inflammatory rheumatic diseases (AIIRD) published in 2011. Four systematic literature reviews were performed regarding the incidence/prevalence of vaccine-preventable infections among patients with AIIRD; efficacy, immunogenicity and safety of vaccines; effect of anti-rheumatic drugs on the response to vaccines; effect of vaccination of household of AIIRDs patients. Subsequently, recommendations were formulated based on the evidence and expert opinion. The updated recommendations comprise six overarching principles and nine recommendations. The former address the need for an annual vaccination status assessment, shared decision-making and timing of vaccination, favouring vaccination during quiescent disease, preferably prior to the initiation of immunosuppression. Non-live vaccines can be safely provided to AIIRD patients regardless of underlying therapy, whereas live-attenuated vaccines may be considered with caution. Influenza and pneumococcal vaccination should be strongly considered for the majority of patients with AIIRD. Tetanus toxoid and human papilloma virus vaccination should be provided to AIIRD patients as recommended for the general population. Hepatitis A, hepatitis B and herpes zoster vaccination should be administered to AIIRD patients at risk. Immunocompetent household members of patients with AIIRD should receive vaccines according to national guidelines, except for the oral poliomyelitis vaccine. Live-attenuated vaccines should be avoided during the first 6 months of life in newborns of mothers treated with biologics during the second half of pregnancy. These 2019 EULAR recommendations provide an up-to-date guidance on the management of vaccinations in patients with AIIRD.

Incidence and prevalence of vaccine preventable infections in adult patients with autoimmune inflammatory rheumatic diseases (AIIRD): a systemic literature review informing the 2019 update of the EULAR recommendations for vaccination in adult patients with AIIRD.

Objectives: The aims of this study were to update the evidence on the incidence and prevalence rates of vaccine preventable infections (VPI) in patients with autoimmune inflammatory rheumatic diseases (AIIRD) and compare the data to the general population when available. Methods: A literature search was performed using Medline, Embase and Cochrane library (October 2009 to August 2018). The primary outcome was the incidence or prevalence of VPI in the adult AIIRD population. Meta-analysis was performed when appropriate. Results: Sixty-three publications out of 3876 identified records met the inclusion criteria: influenza (n=4), pneumococcal disease (n=7), hepatitis B (n=10), herpes zoster (HZ) (n=29), human papillomavirus (HPV) infection (n=13). An increased incidence of influenza and pneumococcal disease was reported in patients with AIIRD. HZ infection-pooled incidence rate ratio (IRR) was 2.9 (95% CI 2.4 to 3.3) in patients with AIIRD versus general population. Among AIIRD, inflammatory myositis conferred the highest incidence rate (IR) of HZ (pooled IRR 5.1, 95% CI 4.3 to 5.9), followed by systemic lupus erythematosus (SLE) (pooled IRR 4.0, 95% CI 2.3 to 5.7) and rheumatoid arthritis (pooled IRR 2.3, 95% CI 2.1 to 2.6). HPV infection-pooled prevalence ratio was 1.6, 95% CI 0.7 to 3.4 versus general population, based on studies mainly conducted in the SLE population in Latin America and Asia. Pooled prevalence of hepatitis B surface antigen and hepatitis B core antibody in patients with AIIRD was similar to the general population, 3%, 95% CI 1% to 5% and 15%, 95% CI 7% to 26%, respectively. Conclusion: Current evidence shows an increased risk of VPI in patients with AIIRD, emphasising that prevention of infections is essential in these patients.

Efficacy, immunogenicity and safety of vaccination in adult patients with autoimmune inflammatory rheumatic diseases: a systematic literature review for the 2019 update of EULAR recommendations.

Aim: To present a systematic literature review (SLR) on efficacy, immunogenicity and safety of vaccination in adult patients with autoimmune inflammatory rheumatic diseases (AIIRD), aiming to provide a basis for updating the EULAR evidence-based recommendations. Methods: An SLR was performed according to the standard operating procedures for EULAR-endorsed recommendations. Outcome was determined by efficacy, immunogenicity and safety of vaccination in adult patients with AIIRD, including those receiving immunomodulating therapy. Furthermore, a search was performed on the effect of vaccinating household members of patients with AIIRD on the occurrence of vaccine-preventable infections in patients and their household members (including newborns). The literature search was performed using Medline, Embase and the Cochrane Library (October 2009 to August 2018). Results: While most investigated vaccines were efficacious and/or immunogenic in patients with AIIRD, some were less efficacious than in healthy control subjects, and/or in patients receiving immunosuppressive agents. Adverse events of vaccination were generally mild and the rates were comparable to those in healthy persons. Vaccination did not seem to lead to an increase in activity of the underlying AIIRD, but insufficient power of most studies precluded arriving at definite conclusions. The number of studies investigating clinical efficacy of vaccination is still limited. No studies on the effect of vaccinating household members of patients with AIIRD were retrieved. Conclusion: Evidence on efficacy, immunogenicity and safety of vaccination in patients with AIIRD was systematically reviewed to provide a basis for updated recommendations.

Surface Tensions of Picoliter Droplets with Sub-Millisecond Surface Age.

Aerosols are key components of the atmosphere and play important roles in many industrial processes. Because aerosol particles have high surface-to-volume ratios, their surface properties are especially important. However, direct measurement of the surface properties of aerosol particles is challenging. In this work, we describe an approach to measure the surface tension of picoliter volume droplets with surface age <1 ms by resolving their dynamic oscillations in shape immediately after ejection from a microdroplet dispenser. Droplet shape oscillations are monitored by highly time-resolved (500 ns) stroboscopic imaging, and droplet surface tension is accurately retrieved across a wide range of droplet sizes (10-25 µm radius) and surface ages (down to ∼100 µs). The approach is validated for droplets containing sodium chloride, glutaric acid, and water, which all show no variation in surface tension with surface age. Experimental results from the microdroplet dispenser approach are compared to complementary surface tension measurements of 5-10 µm radius droplets with aged surfaces using a holographic optical tweezers approach and predictions of surface tension using a statistical thermodynamic model. These approaches combined will allow investigation of droplet surface tension across a wide range of droplet sizes, compositions, and surface ages.

Coalescence Sampling and Analysis of Aerosols using Aerosol Optical Tweezers.

We present a first exploratory study to assess the use of aerosol optical tweezers as an instrument for sampling and detecting accumulation- and coarse-mode aerosol. A subpicoliter aqueous aerosol droplet is captured in the optical trap and used as a sampling volume, accreting mass from a free-flowing aerosol generated by a medical nebulizer or atomizer. Real-time measurements of the initial stability in size, refractive index, and composition of the sampling droplet inferred from Raman spectroscopy confirm that these quantities can be measured with high accuracy and low noise. Typical standard deviations in size and refractive index of the sampling droplet over a period of 200 s are <±2 nm and <±0.0005, respectively, equivalent to <±0.04% in both measured quantities. A standard deviation of <±1% over a 200 s period is achieved in the spontaneous Raman intensity measurement. When sampling coarse-mode aerosol, mass changes of <10 pg can be detected by the sampling droplet as discrete coalescence events. With accumulation-mode aerosol, we show that fluxes as low as 0.068 pg s-1 can be detected over a 50 s period, equivalent to ∼3 pg of sampled material.

Deviations from plane-wave Mie scattering and precise retrieval of refractive index for a single spherical particle in an optical cavity.

The extinction cross-sections of individual, optically confined aerosol particles with radii of a micrometer or less can, in principle, be measured using cavity ring-down spectroscopy (CRDS). However, when the particle radius is comparable in magnitude to the wavelength of light stored in a high-finesse cavity, the phenomenological cross-section retrieved from a CRDS experiment depends on the location of the particle in the intracavity standing wave and differs from the Mie scattering cross-section for plane-wave irradiation. Using an evaporating 1,2,6-hexanetriol particle of initial radius ∼1.75 µm confined within the 4.5 µm diameter core of a Bessel beam, we demonstrate that the scatter in the retrieved extinction efficiency of a single particle is determined by its lateral motion, which spans a few wavelengths of the intracavity standing wave used for CRDS measurements. Fits of experimental measurements to Mie calculations, modified to account for the intracavity standing wave, allow precise retrieval of the refractive index of 1,2,6-hexanetriol particles (with relative humidity, RH < 10%) of 1.47824 ± 0.00072.

Timescales of water transport in viscous aerosol: measurements on sub-micron particles and dependence on conditioning history.

Evaporation studies of single aqueous sucrose aerosol particles as a function of relative humidity (RH) are presented for coarse and fine mode particles down into the submicron size range (600 nm < r < 3.0 µm). These sucrose particles serve as a proxy for biogenic secondary organic aerosols that have been shown to exist, under ambient conditions, in an ultraviscous glassy state, which can affect the kinetics of water mass transport within the bulk phase and hinder particle response to changes in the gas phase water content. A counter-propagating Bessel beams (CPBBs) optical trapping setup is employed to monitor the real-time change in the particle radius with RH decreasing from 75% to 5%. The slow-down of the size change upon each RH step and the deviation from the theoretical equilibrium hygroscopic growth curve indicate the onset of glassy behavior in the RH range of 10-40%. Size-dependent effects were not observed within the uncertainty of the measurements. The influence of the drying time below the glass transition RH on the timescale of subsequent water condensation and re-equilibration for sucrose particles is explored by optical tweezers measurements of micron-sized particles (3 µm < r < 6 µm). The timescale for water condensation and re-equilibration is shown to increase with increasing drying time, i.e. the time over which a viscous particle is dried below 5% RH. These studies demonstrate the importance of the history of the particle conditioning on subsequent water condensation and re-equilibration dynamics of ultraviscous and glassy aerosol particles.

Measurements of the evaporation and hygroscopic response of single fine-mode aerosol particles using a Bessel beam optical trap.

A single horizontally-propagating zeroth order Bessel laser beam with a counter-propagating gas flow was used to confine single fine-mode aerosol particles over extended periods of time, during which process measurements were performed. Particle sizes were measured by the analysis of the angular variation of light scattered at 532 nm by a particle in the Bessel beam, using either a probe beam at 405 nm or 633 nm. The vapour pressures of glycerol and 1,2,6-hexanetriol particles were determined to be 7.5 ± 2.6 mPa and 0.20 ± 0.02 mPa respectively. The lower volatility of hexanetriol allowed better definition of the trapping environment relative humidity profile over the measurement time period, thus higher precision measurements were obtained compared to those for glycerol. The size evolution of a hexanetriol particle, as well as its refractive index at wavelengths 532 nm and 405 nm, were determined by modelling its position along the Bessel beam propagation length while collecting phase functions with the 405 nm probe beam. Measurements of the hygroscopic growth of sodium chloride and ammonium sulfate have been performed on particles as small as 350 nm in radius, with growth curves well described by widely used equilibrium state models. These are the smallest particles for which single-particle hygroscopicity has been measured and represent the first measurements of hygroscopicity on fine mode and near-accumulation mode aerosols, the size regimes bearing the most atmospheric relevance in terms of loading, light extinction and scattering. Finally, the technique is contrasted with other single particle and ensemble methods, and limitations are assessed.

REM sleep behavior disorder in Parkinson's disease: A case from India confirmed with polysomnographic data.

Rapid eye movement (REM) sleep behavior disorder is a condition characterized by dream enactment. This condition may accompany neurodegenerative disorders. However, only a few reports from India are available, that too, without any polysomnographic evidence. We are reporting a case of REM sleep behavior disorder with polysomnographic evidence.

The future state of clinical data capture and documentation: a report from AMIA's 2011 Policy Meeting.

Much of what is currently documented in the electronic health record is in response toincreasingly complex and prescriptive medicolegal, reimbursement, and regulatory requirements. These requirements often result in redundant data capture and cumbersome documentation processes. AMIA's 2011 Health Policy Meeting examined key issues in this arena and envisioned changes to help move toward an ideal future state of clinical data capture and documentation. The consensus of the meeting was that, in the move to a technology-enabled healthcare environment, the main purpose of documentation should be to support patient care and improved outcomes for individuals and populations and that documentation for other purposes should be generated as a byproduct of care delivery. This paper summarizes meeting deliberations, and highlights policy recommendations and research priorities. The authors recommend development of a national strategy to review and amend public policies to better support technology-enabled data capture and documentation practices.

Measurements of Light Extinction by Single Aerosol Particles.

A Bessel beam optical trap is combined with continuous wave cavity ringdown spectroscopy to measure the extinction cross section of individual aerosol particles. Particles, ∼1 µm in size, can be captured indefinitely and processes that transform size or refractive index studied. The measured light extinction induced by the particle is shown to depend on the position of the particle in the cavity, allowing accurate measurements of the mode structure of a high finesse optical cavity without significant perturbation. The variation in extinction efficiency of a sodium chloride droplet with relative humidity is shown to agree well with predictions from Mie scattering theory.

Selection and characterization of aerosol particle size using a bessel beam optical trap for single particle analysis.

Bessel beams were used to create a counter-propagating optical trap for capturing and manipulating aerosol particles. Aerosol droplets were characterized through measurement of the elastic scattered light at three wavelengths; the trapping wavelength of 532 nm was used in conjunction with two probe beams at 405 nm and 633 nm to reduce the uncertainty in estimating droplet radii of 1 µm or less. Control of the aerosol size distribution sampled by the counter-propagating trap was demonstrated by varying the trapping beam core diameters and intensities. Smaller droplet sizes were preferentially selected with a 1.7 µm core diameter compared to cores of 2.7 µm and 4.5 µm. Further, an increase in core intensity was shown to broaden the range in droplet sizes that were optically trapped. The possibility of using such an approach to isolate and analyze the properties of single accumulation mode aerosol particles is discussed.