Estimating Risk from Ambient Concentrations of Acrolein across the United States

BACKGROUND: Estimated ambient concentrations of acrolein, a hazardous air pollutant, are greater than the U.S. Environmental Protection Agency (EPA) reference concentration throughout the United States, making it a concern for human health. However, there is no method for assessing the extent of risk under the U.S. EPA noncancer risk assessment framework. OBJECTIVES: We estimated excess risks from ambient concentrations of acrolein based on dose–response modeling of a study in rats with a relationship between acrolein and residual volume/total lung capacity ratio (RV/TLC) and specific compliance (sC(L)), markers for altered lung function. METHODS: Based on existing literature, we defined values above the 90th percentile for controls as “adverse.” We estimated the increase over baseline response that would occur in the human population from estimated ambient concentrations of acrolein, taken from the U.S. EPA’s National-Scale Air Toxics Assessment for 1999, after standard animal-to-human conversions and extrapolating to doses below the experimental data. RESULTS: The estimated median additional number of adverse sC(L) outcomes across the United States was approximately 2.5 cases per 1,000 people. The estimated range of additional outcomes from the 5th to the 95th percentile of acrolein concentration levels across census tracts was 0.28–14 cases per 1,000. For RV/TLC, the median additional outcome was 0.002 per 1,000, and the additional outcome at the 95th percentile was 0.13 per 1,000. CONCLUSIONS: Although there are uncertainties in estimating human risks from animal data, this analysis demonstrates a method for estimating health risks for noncancer effects and suggests that acrolein could be associated with decreased respiratory function in the United States

Impact testing to determine the mechanical properties of articular cartilage in isolation and on bone

The original publication is available at www.springerlink.comNon peer reviewedPostprin

Cadaveric Simulation of Endoscopic Endonasal Procedures: Analysis of Droplet Splatter Patterns During the COVID-19 Pandemic

Objective The primary mode of viral transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is thought to occur through the spread of respiratory droplets. The objective of this study was to investigate droplet and splatter patterns resulting from common endoscopic endonasal procedures. Study Design Cadaver simulation series. Setting Dedicated surgical laboratory. Subjects and Methods After instilling cadaver head specimens (n = 2) with fluorescein solution, endoscopic endonasal procedures were systematically performed to evaluate the quantity, size, and distance of droplets and splatter following each experimental condition. Results There were no observable fluorescein droplets or splatter noted in the measured surgical field in any direction after nasal endoscopy, septoplasty with microdebrider-assisted turbinoplasty, cold-steel functional endoscopic sinus surgery (FESS), and all experimental conditions using an ultrasonic aspirator. Limited droplet spread was noted with microdebrider FESS (2 droplets, <1 mm in size, within 10 cm), drilling of the sphenoid rostrum with a diamond burr (8, <1 mm, 12 cm), and drilling of the frontal beak with a cutting burr (5, <1 mm, 9 cm); however, the use of concurrent suction while drilling resulted in no droplets or splatter. The control condition of external activation of the drill resulted in gross contamination (11, 2 cm, 13 cm). Conclusion Our results indicate that there is very little droplet generation from routine rhinologic procedures. The droplet generation from drilling was mitigated with the use of concurrent suction. Extreme caution should be used to avoid activating powered instrumentation outside of the nasal cavity, which was found to cause droplet contamination

Mitigation of Aerosols Generated During Rhinologic Surgery: A Pandemic-Era Cadaveric Simulation

Objective: After significant restrictions initially due to the COVID-19 pandemic, otolaryngologists have begun resuming normal clinical practice. However, the risk of SARS-CoV2 transmission to health care workers through aerosolization and airborne transmission during rhinologic surgery remains incompletely characterized. The objective of this study was to quantify the number concentrations of aerosols generated during rhinologic surgery with and without interventions involving 3 passive suction devices. Study Design: Cadaver simulation. Setting: Dedicated surgical laboratory. Subjects and Methods: In a simulation of rhinologic procedures with and without different passive suction interventions, the concentrations of generated aerosols in the particle size range of 0.30 to 10.0 mm were quantified with an optical particle sizer. Results: Functional endoscopic sinus surgery with and without microdebrider, high-speed powered drilling, use of an ultrasonic aspirator, and electrocautery all produced statistically significant increases in concentrations of aerosols of various sizes (P \.05). Powered drilling, ultrasonic aspirator, and electrocautery generated the highest concentration of aerosols, predominantly submicroparticles \1 mm. All interventions with a suction device were effective in reducing aerosols, though the surgical smoke evacuation system was the most effective passive suction method in 2 of the 5 surgical conditions with statistical significance (P \.05). Conclusion. Significant aerosol concentrations were produced in the range of 0.30 to 10.0 mm during all rhinologic procedures in this cadaver simulation. Rhinologic surgery with a passive suction device results in significant mitigation of generated aerosols

HeII->HeI Recombination of Primordial Helium Plasma Including the Effect of Neutral Hydrogen

The HeII->HeI recombination of primordial helium plasma (z = 1500 - 3000) is considered in terms of the standard cosmological model. This process affects the formation of cosmic microwave background anisotropy and spectral distortions. We investigate the effect of neutral hydrogen on the HeII->HeI recombination kinetics with partial and complete redistributions of radiation in frequency in the HeI resonance lines. It is shown that to properly compute the HeII->HeI recombination kinetics, one should take into account not only the wings in the absorption and emission profiles of the HeI resonance lines, but also the mechanism of the redistribution of resonance photons in frequency. Thus, for example, the relative difference in the numbers of free electrons for the model using Doppler absorption and emission profiles and the model using a partial redistribution in frequency is 1 - 1.3% for the epoch z = 1770 - 1920. The relative difference in the numbers of free electrons for the model using a partial redistribution in frequency and the model using a complete redistribution in frequency is 1 - 3.8% for the epoch z = 1750 - 2350.Comment: 28 pages, 9 figures, 2 tabel

Direct Observation of Propagating Gigahertz Coherent Guided Acoustic Phonons in Free Standing Single Copper Nanowires

We report on gigahertz acoustic phonon waveguiding in free-standing single copper nanowires studied by femtosecond transient reflectivity measurements. The results are discussed on the basis of the semianalytical resolution of the Pochhammer and Chree equation. The spreading of the generated Gaussian wave packet of two different modes is derived analytically and compared with the observed oscillations of the sample reflectivity. These experiments provide a unique way to independently obtain geometrical and material characterization. This direct observation of coherent guided acoustic phonons in a single nano-object is also the first step toward nanolateral size acoustic transducer and comprehensive studies of the thermal properties of nanowires

‘Video Replay: Families, films and fantasy’ as a transformational text: Commentary on Valerie Walkerdine's ‘Video Replay’.

In this commentary I explore the significance of Valerie Walkerdine's paper ‘Video Replay: Families, Films and Fantasy’. I review its impact in 1986 and then discuss how some of its ideas about subjectivity and popular culture – specifically film - can be developed in the contemporary context. A recurring fantasy of Rocky II and its reception is that of social and psychological transformation. I address this theme by drawing on the work of Christopher Bollas to argue that Walkerdine's psychosocial analysis continues to facilitate, across a range of contexts, some of the transformational processes described in her article

Measurements of Flavour Dependent Fragmentation Functions in Z^0 -> qq(bar) Events

Fragmentation functions for charged particles in Z -> qq(bar) events have been measured for bottom (b), charm (c) and light (uds) quarks as well as for all flavours together. The results are based on data recorded between 1990 and 1995 using the OPAL detector at LEP. Event samples with different flavour compositions were formed using reconstructed D* mesons and secondary vertices. The \xi_p = ln(1/x_E) distributions and the position of their maxima \xi_max are also presented separately for uds, c and b quark events. The fragmentation function for b quarks is significantly softer than for uds quarks.Comment: 29 pages, LaTeX, 5 eps figures (and colour figs) included, submitted to Eur. Phys. J.

Aerosol generation during routine rhinologic surgeries and in-office procedures

Objective Cadaveric simulations have shown endonasal drilling and cautery generate aerosols, which is a significant concern for otolaryngologists during the COVID‐19 era. This study quantifies aerosol generation during routine rhinologic surgeries and in‐office procedures in live patients. Methods Aerosols ranging from 0.30 to 10.0 μm were measured in real‐time using an optical particle sizer during surgeries and in‐office procedures. Various mask conditions were tested during rigid nasal endoscopy (RNE) and postoperative debridement (POD). Results Higher aerosol concentrations (AC) ranging from 2.69 to 10.0 μm were measured during RNE (n = 9) with no mask vs two mask conditions (P = .002 and P = .017). Mean AC (0.30‐10.0 μm) were significantly higher during POD (n = 9) for no mask vs a mask covering the patient's mouth condition (mean difference = 0.16 ± 0.03 particles/cm3, 95% CI 0.10‐0.22, P < .001). There were no discernible spikes in aerosol levels during endoscopic septoplasty (n = 3). Aerosol spikes were measured in two of three functional endoscopic sinus surgeries (FESS) with microdebrider. Using suction mitigation, there were no discernible spikes during powered drilling in two anterior skull base surgeries (ASBS). Conclusion Use of a surgical mask over the patient's mouth during in‐office procedures or a mask with a slit for an endoscope during RNE significantly diminished aerosol generation. However, whether this reduction in aerosol generation is sufficient to prevent transmission of communicable diseases via aerosols was beyond the scope of this study. There were several spikes in aerosols during FESS and ASBS, though none were associated with endonasal drilling with the use of suction mitigation

Measuring Biodiversity and Extinction – Present and Past

How biodiversity is changing in our time represents a major concern for all organismal biologists. Anthropogenic changes to our planet are decreasing species diversity through the negative effects of pollution, habitat destruction, direct extirpation of species, and climate change. But major biotic changes – including those that have both increased and decreased species diversity – have happened before in Earth’s history. Biodiversity dynamics in past eras provide important context to understand ecological responses to current environmental change. The work of assessing biodiversity is woven into ecology, environmental science, conservation, paleontology, phylogenetics, evolutionary and developmental biology, and many other disciplines; yet, the absolute foundation of how we measure species diversity depends on taxonomy and systematics. The aspiration of this symposium, and complementary contributed talks, was to promote better understanding of our common goals and encourage future interdisciplinary discussion of biodiversity dynamics. The contributions in this collection of papers bring together a diverse group of speakers to confront several important themes. How can biologists best respond to the urgent need to identify and conserve diversity? How can we better communicate the nature of species across scientific disciplines? Where are the major gaps in knowledge about the diversity of living animal and plant groups, and what are the implications for understanding potential diversity loss? How can we effectively use the fossil record of past diversity and extinction to understand current biodiversity loss