The Underlying Mechanism of Poisoning after the Accidental Inhalation of Aerosolised Waterproofing Spray.

Waterproofing sprays can cause acute respiratory symptoms after inhalation, including coughing and dyspnoea shortly after use. Here, we describe two cases where persons used the same brand of waterproofing spray product. In both cases the persons followed the instructions on the product and maximized the ventilation by opening windows and doors; however, they still became affected during the application of the product. Products with the same batch number as that used in one case were tested for their effect on respiration patterns of mice in whole-body plethysmographs and lung surfactant function inhibition in vitro. The product was used in spraying experiments to determine the particle size distribution of the aerosol, both using a can from one case and a can with an identical batch number. In addition, the aerosols in the mouse exposure chamber were measured. Aerosol data from a small-scale exposure chamber and data on the physical and temporal dimensions of the spraying during one case were used to estimate the deposited dose during the spraying events. All collected data point to the spraying of the waterproofing product being the reason that two people became ill, and that the inhibition of lung surfactant function was a key component of this illness.

Parental differential treatment of siblings linked with internalizing and externalizing behavior: A meta-analysis.

This meta-analysis linked relative and absolute parental differential treatment (PDT) with internalizing and externalizing behavior of children and adolescents. Multilevel meta-analysis data represented 26,451 participants based on 2890 effect sizes coming from 88 sources, nested within 43 samples. Participants were between 3.18 and 18.99 years of age (Mage = 12.64, SD = 3.89; 51.31% female; 82.23% White; 54.68% from the United States). Less-favored treatment (relative PDT) was linked to more internalizing and externalizing behavior. Additionally, greater differences in parenting between siblings (absolute PDT) were linked to more internalizing and externalizing behavior. Some links were moderated by other factors. For example, some effects were stronger when PDT was reported by children, and others, when siblings were closer in age.

Use of the dustiness index in combination with the handling energy factor for exposure modelling of nanomaterials.

The use of modelling tools in the occupational hygiene community has increased in the last years to comply with the different existing regulations. However, limitations still exist mainly due to the difficulty to obtain certain key parameters such as the emission rate, which in the case of powder handling can be estimated using the dustiness index (DI). The goal of this work is to explore the applicability and usability of the DI for emission source characterization and occupational exposure prediction to particles during nanomaterial powder handling. Modelling of occupational exposure concentrations of 13 case scenarios was performed using a two-box model as well as three nano-specific tools (Stoffenmanager nano, NanoSafer and GUIDEnano). The improvement of modelling performance by using a derived handling energy factor (H) was explored. Results show the usability of the DI for emission source characterization and respirable mass exposure modelling of powder handling scenarios of nanomaterials. A clear improvement in modelling outcome was obtained when using derived quartile-3 H factors with, 1) Pearson correlations of 0.88 vs. 0.52 (not using H), and 2) ratio of modelled/measured concentrations ranging from 0.9 to 10 in 75% cases vs. 16.7% of the cases when not using H. Particle number concentrations were generally underpredicted. Using the most conservative H values, predictions with ratios modelled/measured concentrations of 0.4-3.6 were obtained.

Modeling ocean distributions and abundances of natural- and hatchery-origin Chinook salmon stocks with integrated genetic and tagging data.

Background: Considerable resources are spent to track fish movement in marine environments, often with the intent of estimating behavior, distribution, and abundance. Resulting data from these monitoring efforts, including tagging studies and genetic sampling, often can be siloed. For Pacific salmon in the Northeast Pacific Ocean, predominant data sources for fish monitoring are coded wire tags (CWTs) and genetic stock identification (GSI). Despite their complementary strengths and weaknesses in coverage and information content, the two data streams rarely have been integrated to inform Pacific salmon biology and management. Joint, or integrated, models can combine and contextualize multiple data sources in a single statistical framework to produce more robust estimates of fish populations. Methods: We introduce and fit a comprehensive joint model that integrates data from CWT recoveries and GSI sampling to inform the marine life history of Chinook salmon stocks at spatial and temporal scales relevant to ongoing fisheries management efforts. In a departure from similar models based primarily on CWT recoveries, modeled stocks in the new framework encompass both hatchery- and natural-origin fish. We specifically model the spatial distribution and marine abundance of four distinct stocks with spawning locations in California and southern Oregon, one of which is listed under the U.S. Endangered Species Act. Results: Using the joint model, we generated the most comprehensive estimates of marine distribution to date for all modeled Chinook salmon stocks, including historically data poor and low abundance stocks. Estimated marine distributions from the joint model were broadly similar to estimates from a simpler, CWT-only model but did suggest some differences in distribution in select seasons. Model output also included novel stock-, year-, and season-specific estimates of marine abundance. We observed and partially addressed several challenges in model convergence with the use of supplemental data sources and model constraints; similar difficulties are not unexpected with integrated modeling. We identify several options for improved data collection that could address issues in convergence and increase confidence in model estimates of abundance. We expect these model advances and results provide management-relevant biological insights, with the potential to inform future mixed-stock fisheries management efforts, as well as a foundation for more expansive and comprehensive analyses to follow.

Characterization of the aerosol release from spray cleaning and disinfection products - Spray scenarios in a climate chamber.

Cleaning work using spray products has been associated with adverse respiratory effects but little is known of the exposure concentrations. The purpose of this study was to characterize aerosol generation at spray scenarios in a controlled climate chamber. Spraying on vertically and horizontally oriented surfaces, as well as spraying on a cloth, was investigated. Furthermore, the effect of nozzle geometry was tested. The average mass generation rates of six pressurized spray cans and 13 trigger sprays were about 1.7 g/s and did not differ significantly, but the average values of the individual sprays had large variations (0.5-3.1 g/s). The time required to halve the air concentration of aerosol particles, the half-life time, was determined for all spray products. The average half-life time of the total particle mass concentration (TPMC) of the pressurized spray cans was 0.5 h versus 0.25 h for trigger sprays. Gravimetrically determined airborne fractions of pressurized spray cans tended to be higher than those of trigger sprays. However, airborne fractions based on the measured peak TPMC were up to three orders of magnitude smaller. A comparison of different trigger spray nozzles when spraying the same product showed that the TPMC can be up to 18 times higher for the largest emitting nozzle. The distance of the nozzle to a cloth should be 1 cm to significantly reduce the concentration of the generated aerosols. ConsExpo modeling predicted the measured peak TPMC well but less well the decay.

Signal and noise in metabarcoding data.

Metabarcoding is a powerful molecular tool for simultaneously surveying hundreds to thousands of species from a single sample, underpinning microbiome and environmental DNA (eDNA) methods. Deriving quantitative estimates of underlying biological communities from metabarcoding is critical for enhancing the utility of such approaches for health and conservation. Recent work has demonstrated that correcting for amplification biases in genetic metabarcoding data can yield quantitative estimates of template DNA concentrations. However, a major source of uncertainty in metabarcoding data stems from non-detections across technical PCR replicates where one replicate fails to detect a species observed in other replicates. Such non-detections are a special case of variability among technical replicates in metabarcoding data. While many sampling and amplification processes underlie observed variation in metabarcoding data, understanding the causes of non-detections is an important step in distinguishing signal from noise in metabarcoding studies. Here, we use both simulated and empirical data to 1) suggest how non-detections may arise in metabarcoding data, 2) outline steps to recognize uninformative data in practice, and 3) identify the conditions under which amplicon sequence data can reliably detect underlying biological signals. We show with both simulations and empirical data that, for a given species, the rate of non-detections among technical replicates is a function of both the template DNA concentration and species-specific amplification efficiency. Consequently, we conclude metabarcoding datasets are strongly affected by (1) deterministic amplification biases during PCR and (2) stochastic sampling of amplicons during sequencing-both of which we can model-but also by (3) stochastic sampling of rare molecules prior to PCR, which remains a frontier for quantitative metabarcoding. Our results highlight the importance of estimating species-specific amplification efficiencies and critically evaluating patterns of non-detection in metabarcoding datasets to better distinguish environmental signal from the noise inherent in molecular detections of rare targets.

Correlation between inhibition of lung surfactant function in vitro and rapid reduction in tidal volume following exposure to plant protection products in mice.

Currently, testing of acute inhalation toxicity in animals is required for regulation of pesticide active ingredients and formulated plant protection products. The main outcome of the regulatory tests is "lethal concentration 50″ (LC50), i.e. the concentration that will kill 50% of the exposed animals. However, ongoing work aims to identify New Approach Methods (NAMs) to replace animal experiments. To this end, we studied 11 plant protection products, sold in the European Union (EU), for their ability to inhibit lung surfactant function in vitro in the constrained drop surfactometer (CDS). In vivo, inhibition of lung surfactant function can lead to alveolar collapse and reduction of tidal volume. Therefore, we also assessed changes in breathing patterns of mice during exposure to the same products. Six of the eleven products inhibited lung surfactant function, and six products reduced tidal volume in mice. In vitro inhibition of lung surfactant function predicted reduction in tidal volume in exposed mice with a sensitivity of 67% and a specificity of 60%. Two products were labelled as "harmful if inhaled", both inhibited surfactant function in vitro and reduced tidal volume in mice. Lung surfactant function inhibition in vitro predicted reduction in tidal volume for plant protection products to a lesser degree than for previously tested substances. This could owe to the requirement for rigorous testing of plant protection products prior to approval that might have selected against substances that could potentially inhibit lung surfactant, e.g. due to severe adverse effects during inhalation.

Genotoxicity in the absence of inflammation after tungsten inhalation in mice.

Tungsten is used in several applications and human exposure may occur. To assess its pulmonary toxicity, we exposed male mice to nose-only inhalation of tungsten particles at 9, 23 or 132 mg/m3 (Low, Mid and High exposure) (45 min/day, 5 days/week for 2 weeks). Increased genotoxicity (assessed by comet assay) was seen in bronchoalveolar (BAL) fluid cells at Low and High exposure. We measured acellular ROS production, and cannot exclude that ROS contributed to the observed genotoxicity. We saw no effects on body weight gain, pulmonary inflammation, lactate dehydrogenase or protein in BAL fluid, pathology of liver or kidney, or on sperm counts. In conclusion, tungsten showed non-dose dependent genotoxicity in the absence of inflammation and therefore interpreted to be primary genotoxicity. Based on genotoxicity, a Lowest Observed Adverse Effect Concentration (LOAEC) could be set at 9 mg/m3. It was not possible to establish a No Adverse Effect Concentration (NOAEC).

Pulmonary toxicity of molybdenum disulphide after inhalation in mice.

Molybdenum disulphide (MoS2) is a constituent of many products. To protect humans, it is important to know at what air concentrations it becomes toxic. For this, we tested MoS2 particles by nose-only inhalation in mice. Exposures were set to 13, 50 and 150 mg MoS2/m3 (=8, 30 and 90 mg Mo/m3), corresponding to Low, Mid and High exposure. The duration was 30 min/day, 5 days/week for 3 weeks. Molybdenum lung-deposition levels were estimated based on aerosol particle size distribution measurements, and empirically determined with inductively coupled plasma-mass spectrometry (ICP-MS). Toxicological endpoints were body weight gain, respiratory function, pulmonary inflammation, histopathology, and genotoxicity (comet assay). Acellular reactive oxygen species (ROS) production was also determined. The aerosolised MoS2 powder had a mean aerodynamic diameter of 800 nm, and a specific surface area of 8.96 m2/g. Alveolar deposition of MoS2 in lung was estimated at 7, 27 and 79 µg/mouse and measured as 35, 101 and 171 µg/mouse for Low, Mid and High exposure, respectively. Body weight gain was lower than in controls at Mid and High exposure. The tidal volume was decreased with Low and Mid exposure on day 15. Increased genotoxicity was seen in bronchoalveolar lavage (BAL) fluid cells at Mid and High exposures. ROS production was substantially lower than for carbon black nanoparticles used as bench-mark, when normalised by mass. Yet if ROS of MoS2 was normalised by surface area, it was similar to that of carbon black, suggesting that a ROS contribution to the observed genotoxicity cannot be ruled out. In conclusion, effects on body weight gain and genotoxicity indicated that Low exposure (13 mg MoS2/m3, corresponding to 0.8 mg/m3 for an 8-hour working day) was a No Observed Adverse Effect Concentration (NOAEC,) while effects on respiratory function suggested this level as a Lowest Observed Adverse Effect Concentration (LOAEC).

Sibling differences and parents' differential treatment of siblings: A multilevel meta-analysis.

The current study used meta-analysis to ask whether age differences, sex differences, and family size are linked to differences in parental treatment, as well as whether effect-sizes were moderated by the way parental differential treatment (PDT) was measured, who reported on the PDT, and the domain of PDT. Between August 2015 and November 2020, PsycINFO, Google Scholar, and PubMed Central were searched for articles relating to parental differential treatment; additionally, 13 sibling relationship scholars were contacted to collect unpublished analyses or unused data. Multilevel data came from 13,628 unique participants across 1,388 effect sizes nested within 66 sources (articles/raw data sets), nested within 23 unique samples (74% from North America; 26% from Western Europe). Multilevel meta-analysis conducted in R with the metafor package showed greater differences in parental treatment when siblings were further apart in age or a different sex. The main effects for age spacing, however, were moderated by several factors, particularly the domain of parenting. Specifically, age spacing was linked only to PDT based on control or autonomy granting, meaning when siblings were further apart in age, parents granted more autonomy to one sibling over another. Results were limited, however, by limited sample sizes at the sample level. Overall, findings suggest that parents may, in part, treat siblings differently because they are different to begin with. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Toward quantitative metabarcoding.

Amplicon-sequence data from environmental DNA (eDNA) and microbiome studies provide important information for ecology, conservation, management, and health. At present, amplicon-sequencing studies-known also as metabarcoding studies, in which the primary data consist of targeted, amplified fragments of DNA sequenced from many taxa in a mixture-struggle to link genetic observations to the underlying biology in a quantitative way, but many applications require quantitative information about the taxa or systems under scrutiny. As metabarcoding studies proliferate in ecology, it becomes more important to develop ways to make them quantitative to ensure that their conclusions are adequately supported. Here we link previously disparate sets of techniques for making such data quantitative, showing that the underlying polymerase chain reaction mechanism explains the observed patterns of amplicon data in a general way. By modeling the process through which amplicon-sequence data arise, rather than transforming the data post hoc, we show how to estimate the starting DNA proportions from a mixture of many taxa. We illustrate how to calibrate the model using mock communities and apply the approach to simulated data and a series of empirical examples. Our approach opens the door to improve the use of metabarcoding data in a wide range of applications in ecology, public health, and related fields.

Very large-scale diffraction investigations enabled by a matrix-multiplication facilitated radial and azimuthal integration algorithm: MatFRAIA.

As synchrotron facilities continue to generate increasingly brilliant X-rays and detector speeds increase, swift data reduction from the collected area detector images to more workable 1D diffractograms becomes of increasing importance. This work reports an integration algorithm that can integrate diffractograms in real time on modern laptops and can reach 10 kHz integration speeds on modern workstations using an efficient pixel-splitting and parallelization scheme. This algorithm is limited not by the computation of the integration itself but is rather bottlenecked by the speed of the data transfer to the processor, the data decompression and/or the saving of results. The algorithm and its implementation is described while the performance is investigated on 2D scanning X-ray diffraction/fluorescence data collected at the interface between an implant and forming bone.

Introducing zoid: A mixture model and R package for modeling proportional data with zeros and ones in ecology.

Many ecological data sets are proportional, representing mixtures of constituent elements such as species, populations, or strains. Analyses of proportional data are challenged by categories with zero observations (zeros), all observations (ones), and overdispersion. In lieu of ad hoc data adjustments, we describe and evaluate a zero-and-one inflated Dirichlet regression model, with its corresponding R package (zoid), capable of handling observed data x $$ x $$ consisting of three possible categories: zeros, proportions, or ones. Instead of fitting the model to observations of single biological units (e.g., individual organisms) within a sample, we sum proportional contributions across units and estimate mixture proportions using one aggregated observation per sample. Optional estimation of overdispersion and covariate influences expand model applications. We evaluate model performance, as implemented in Stan, using simulations and two ecological case studies. We show that zoid successfully estimates mixture proportions using simulated data with varying sample sizes and is robust to overdispersion and covariate structure. In empirical case studies, we estimate the composition of a mixed-stock Chinook salmon (Oncorhynchus tshawytscha) fishery and analyze the stomach contents of Atlantic cod (Gadus morhua). Our implementation of the model as an R package facilitates its application to varied ecological data sets composed of proportional observations.

The family stress model and parents' differential treatment of siblings: A multilevel meta-analysis.

The family stress model (FSM) suggests that stress, particularly economic stress, hinders effective parenting. Expanding on the FSM, the present study examined not only the economic stress but also the general stress and several contexts that may promote stress-namely, physical health, mental health, socioeconomic status, employment status, and marital status. The present study also expanded the FSM to examine parenting of sibling groups. Ineffective parenting of sibling groups was conceptualized as greater parental differential treatment (PDT). A number of moderating variables were also considered. Multilevel meta-analysis models were used to test hypotheses. Across models, data came from 6,003 effect sizes, nested within 59 sources, nested within 16 unique samples (all coming from 8 published studies and 11 raw data sets). Results showed main effects for only parents' general stress and parents' mental health. More stress and poorer mental health were linked with greater amounts of PDT. Additionally, poorer physical health was linked to greater PDT but only when PDT involved positive parent-child interactions. As a whole, findings suggested that actual feelings of stress and psychological distress may show stronger links with PDT than contexts that merely have the potential to cause stress. Caution is warranted, however, as effect sizes were generally small and some models were based on predominantly Caucasian samples. Future research on the FSM and PDT should focus on actual experiences of stress and further consider the moderating role of domains of parenting. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Evaluation of One- and Two-Box Models as Particle Exposure Prediction Tools at Industrial Scale.

One- and two-box models have been pointed out as useful tools for modelling indoor particle exposure. However, model performance still needs further testing if they are to be implemented as trustworthy tools for exposure assessment. The objective of this work is to evaluate the performance, applicability and reproducibility of one- and two-box models on real-world industrial scenarios. A study on filling of seven materials in three filling lines with different levels of energy and mitigation strategies was used. Inhalable and respirable mass concentrations were calculated with one- and two-box models. The continuous drop and rotating drum methods were used for emission rate calculation, and ranges from a one-at-a-time methodology were applied for local exhaust ventilation efficiency and inter-zonal air flows. When using both dustiness methods, large differences were observed for modelled inhalable concentrations but not for respirable, which showed the importance to study the linkage between dustiness and processes. Higher model accuracy (ratio modelled vs. measured concentrations 0.5-5) was obtained for the two- (87%) than the one-box model (53%). Large effects on modelled concentrations were seen when local exhausts ventilation and inter-zonal variations where parametrized in the models. However, a certain degree of variation (10-20%) seems acceptable, as similar conclusions are reached.

Occupational Exposure and Environmental Release: The Case Study of Pouring TiO2 and Filler Materials for Paint Production.

Pulmonary exposure to micro- and nanoscaled particles has been widely linked to adverse health effects and high concentrations of respirable particles are expected to occur within and around many industrial settings. In this study, a field-measurement campaign was performed at an industrial manufacturer, during the production of paints. Spatial and personal measurements were conducted and results were used to estimate the mass flows in the facility and the airborne particle release to the outdoor environment. Airborne particle number concentration (1 × 103-1.0 × 104 cm-3), respirable mass (0.06-0.6 mg m-3), and PM10 (0.3-6.5 mg m-3) were measured during pouring activities. In overall; emissions from pouring activities were found to be dominated by coarser particles >300 nm. Even though the raw materials were not identified as nanomaterials by the manufacturers, handling of TiO2 and clays resulted in release of nanometric particles to both workplace air and outdoor environment, which was confirmed by TEM analysis of indoor and stack emission samples. During the measurement period, none of the existing exposure limits in force were exceeded. Particle release to the outdoor environment varied from 6 to 20 g ton-1 at concentrations between 0.6 and 9.7 mg m-3 of total suspended dust depending on the powder. The estimated release of TiO2 to outdoors was 0.9 kg per year. Particle release to the environment is not expected to cause any major impact due to atmospheric dilution.

Look Who's Talking: Mediums of Contact Among Mid-to Later-Life Siblings.

Adult siblings maintain contact and remain close to one another. The current study used participants recruited via Amazon Mechanical Turk (n = 491) to conduct regression analyses examining five methods of contact (in person, telephone, email, texting, and social media) predicting sibling closeness and conflict. Further, two- and three-way interactions assessed the role of sibling dyad composition (e.g., women with a sister and women with a brother). Results suggested that as contact in person, through social media, the telephone, or email increased, sibling closeness increased, while increased contact through email indicated less conflict. Assessing sibling dyad composition suggested as telephone contact increased, sibling closeness increased for all sibling dyads, especially for women with a sister compared to men with a brother. In-person and texting contacts were beneficial for women with a brother. Even in mid- to later-life, siblings connect through synchronous and asynchronous mediums, and this contact appears beneficial for sisters.

Can an InChI for Nano Address the Need for a Simplified Representation of Complex Nanomaterials across Experimental and Nanoinformatics Studies?

Chemoinformatics has developed efficient ways of representing chemical structures for small molecules as simple text strings, simplified molecular-input line-entry system (SMILES) and the IUPAC International Chemical Identifier (InChI), which are machine-readable. In particular, InChIs have been extended to encode formalized representations of mixtures and reactions, and work is ongoing to represent polymers and other macromolecules in this way. The next frontier is encoding the multi-component structures of nanomaterials (NMs) in a machine-readable format to enable linking of datasets for nanoinformatics and regulatory applications. A workshop organized by the H2020 research infrastructure NanoCommons and the nanoinformatics project NanoSolveIT analyzed issues involved in developing an InChI for NMs (NInChI). The layers needed to capture NM structures include but are not limited to: core composition (possibly multi-layered); surface topography; surface coatings or functionalization; doping with other chemicals; and representation of impurities. NM distributions (size, shape, composition, surface properties, etc.), types of chemical linkages connecting surface functionalization and coating molecules to the core, and various crystallographic forms exhibited by NMs also need to be considered. Six case studies were conducted to elucidate requirements for unambiguous description of NMs. The suggested NInChI layers are intended to stimulate further analysis that will lead to the first version of a "nano" extension to the InChI standard.

Nanoparticle Exposure and Workplace Measurements During Processes Related to 3D Printing of a Metal Object.

Metal 3D printing has many potential uses within prototyping and manufacturing. Selective laser melting (SLM) is a process that uses metal powders in the micrometer range as printing material. The particle release from the entire SLM printing process is not well-studied. While the 3D printing itself often occurs in a sealed chamber, activities related to the process can potentially release harmful metal particles to the indoor working environment through resuspension of the printing powder or via incident nanoparticles generated during printing. The objective of this study was to improve the understanding of particle exposure in work processes associated with 3D printing and potential needs for interventions by a case study conducted in a 3D printing facility. In this setting, direct release and dispersion of particles throughout the workspace from processes related to metal 3D printing was investigated. The release from five activities were studied in detail. The activities included post-printing cleaning, object annealing, and preparation of new base substrate for the next printing was. Three of the five measured activities caused particles number concentrations in the working environment to increase above background levels which were found to be 8·102 cm-3. Concentrations during chamber emptying and the open powder removal system (PRS) cleaning processes increased to 104 and 5·103 cm-3, respectively, whereas grinding activity increased number concentrations to 2.5·105 cm-3. Size distributions showed that particles were mainly smaller than 200 nm. Respirable mass concentrations were 50.4 µg m-3, collected on filters. This was corroborated by respirable mass measured with a DustTrak of 58.4 µg m-3. Respirable mass concentrations were below the occupational exposure limits in Denmark for an 8 h time-weighted average.

Acute Inhalation Toxicity After Inhalation of ZnO Nanoparticles: Lung Surfactant Function Inhibition In Vitro Correlates With Reduced Tidal Volume in Mice.

People can be exposed to zinc oxide (ZnO) by inhalation of consumer products or during industrial processes. Zinc oxide nanoparticle (NP) exposure can induce acute inhalation toxicity. The toxicological mechanisms underlying the acute effects on the lungs have long focused on the phagolysosomal dissolution of ZnO NPs in macrophages followed by the release of free Zn2+ ions. However, we postulate an alternative mechanism based on the direct interaction of ZnO NPs with the lung surfactant (LS) layer covering the inside of the alveoli. Therefore, we tested the effect of ZnO NPs and Zn2+ ions on the function of LS in vitro using the constrained drop surfactometer. We found that the ZnO NPs inhibited the LS function, whereas Zn2+ ions did not. To examine the role of lung macrophages in the acute toxicity of inhaled ZnO NPs, mice were treated with Clodrosome, a drug that depletes alveolar macrophages, or Encapsome, the empty carrier of the drug. After macrophage depletion, the mice were exposed to an aerosol of ZnO NPs in whole body plethysmographs recording breathing patterns continuously. Mice in both groups developed shallow breathing (reduced tidal volume) shortly after the onset of exposure to ZnO NPs. This suggests a macrophage-independent mechanism of induction. This study shows that acute inhalation toxicity is caused by ZnO NP interaction with LS, independently of NP dissolution in macrophages.