Pulmonary evaluation of whole-body inhalation exposure of polycarbonate (PC) filament 3D printer emissions in rats.

During fused filament fabrication (FFF) 3D printing with polycarbonate (PC) filament, a release of ultrafine particles (UFPs) and volatile organic compounds (VOCs) occurs. This study aimed to determine PC filament printing emission-induced toxicity in rats via whole-body inhalation exposure. Male Sprague Dawley rats were exposed to a single concentration (0.529 mg/m3, 40 nm mean diameter) of the 3D PC filament emissions in a time-course via whole body inhalation for 1, 4, 8, 15, and 30 days (4 hr/day, 4 days/week), and sacrificed 24 hr after the last exposure. Following exposures, rats were assessed for pulmonary and systemic responses. To determine pulmonary injury, total protein and lactate dehydrogenase (LDH) activity, surfactant proteins A and D, total as well as lavage fluid differential cells in bronchoalveolar lavage fluid (BALF) were examined, as well as histopathological analysis of lung and nasal passages was performed. To determine systemic injury, hematological differentials, and blood biomarkers of muscle, metabolic, renal, and hepatic functions were also measured. Results showed that inhalation exposure induced no marked pulmonary or systemic toxicity in rats. In conclusion, inhalation exposure of rats to a low concentration of PC filament emissions produced no significant pulmonary or systemic toxicity.

Efficacy of Do-It-Yourself air filtration units in reducing exposure to simulated respiratory aerosols.

Many respiratory diseases, including COVID-19, can be spread by aerosols expelled by infected people when they cough, talk, sing, or exhale. Exposure to these aerosols indoors can be reduced by portable air filtration units (air cleaners). Homemade or Do-It-Yourself (DIY) air filtration units are a popular alternative to commercially produced devices, but performance data is limited. Our study used a speaker-audience model to examine the efficacy of two popular types of DIY air filtration units, the Corsi-Rosenthal cube and a modified Ford air filtration unit, in reducing exposure to simulated respiratory aerosols within a mock classroom. Experiments were conducted using four breathing simulators at different locations in the room, one acting as the respiratory aerosol source and three as recipients. Optical particle spectrometers monitored simulated respiratory aerosol particles (0.3-3 µm) as they dispersed throughout the room. Using two DIY cubes (in the front and back of the room) increased the air change rate as much as 12.4 over room ventilation, depending on filter thickness and fan airflow. Using multiple linear regression, each unit increase of air change reduced exposure by 10%. Increasing the number of filters, filter thickness, and fan airflow significantly enhanced the air change rate, which resulted in exposure reductions of up to 73%. Our results show DIY air filtration units can be an effective means of reducing aerosol exposure. However, they also show performance of DIY units can vary considerably depending upon their design, construction, and positioning, and users should be mindful of these limitations.

Lung toxicity profile of inhaled copper-nickel welding fume in A/J mice.

Objective: Stainless steel welding creates fumes rich in carcinogenic metals such as chromium (Cr). Welding consumables devoid of Cr are being produced in an attempt to limit worker exposures to toxic and carcinogenic metals. The study objective was to characterize a copper-nickel (Cu-Ni) fume generated using gas metal arc welding (GMAW) and determine the pulmonary deposition and toxicity of the fume in mice exposed by inhalation. Materials and Methods: Male A/J mice (6-8 weeks of age) were exposed to air or Cu-Ni welding fumes for 2 (low deposition) or 4 (high deposition) hours/day for 10 days. Mice were sacrificed, and bronchoalveolar lavage (BAL), macrophage function, and histopathological analyses were performed at different timepoints post-exposure to evaluate resolution. Results and Discussion: Characterization of the fume indicated that most of the particles were between 0.1 and 1 µm in diameter, with a mass median aerodynamic diameter of 0.43 µm. Metal content of the fume was Cu (∼76%) and Ni (∼12%). Post-exposure, BAL macrophages had a reduced ability to phagocytose E. coli, and lung cytotoxicity was evident and significant (>12%-19% fold change). Loss of body weight was also significant at the early timepoints. Lung inflammation, the predominant finding identified by histopathology, was observed as a subacute response early that progressively resolved by 28 days with only macrophage aggregates remaining late (84 days). Conclusions: Overall, there was high acute lung toxicity with a resolution of the response in mice which suggests that the Cu-Ni fume may not be ideal for reducing toxic and inflammatory lung effects.

Evaluation of Pulmonary Effects of 3-D Printer Emissions From Acrylonitrile Butadiene Styrene Using an Air-Liquid Interface Model of Primary Normal Human-Derived Bronchial Epithelial Cells.

This study investigated the inhalation toxicity of the emissions from 3-D printing with acrylonitrile butadiene styrene (ABS) filament using an air-liquid interface (ALI) in vitro model. Primary normal human-derived bronchial epithelial cells (NHBEs) were exposed to ABS filament emissions in an ALI for 4 hours. The mean and mode diameters of ABS emitted particles in the medium were 175 ± 24 and 153 ± 15 nm, respectively. The average particle deposition per surface area of the epithelium was 2.29 × 107 ± 1.47 × 107 particle/cm2, equivalent to an estimated average particle mass of 0.144 ± 0.042 µg/cm2. Results showed exposure of NHBEs to ABS emissions did not significantly affect epithelium integrity, ciliation, mucus production, nor induce cytotoxicity. At 24 hours after the exposure, significant increases in the pro-inflammatory markers IL-12p70, IL-13, IL-15, IFN-γ, TNF-α, IL-17A, VEGF, MCP-1, and MIP-1α were noted in the basolateral cell culture medium of ABS-exposed cells compared to non-exposed chamber control cells. Results obtained from this study correspond with those from our previous in vivo studies, indicating that the increase in inflammatory mediators occur without associated membrane damage. The combination of the exposure chamber and the ALI-based model is promising for assessing 3-D printer emission-induced toxicity.

An investigation of the effectiveness of vibration-reducing gloves for controlling vibration exposures during grinding handheld workpieces.

Prolonged and intensive vibration exposures during the grinding of handheld workpieces may cause hand-arm vibration syndrome. The objectives of this study are to develop an on-the-hand method for evaluating vibration-reducing (VR) gloves, and to determine whether VR gloves can significantly reduce the vibration exposures. A worker holding and pressing a typical workpiece (golf club head) against a grinding wheel or belt in order to shape the workpiece was simulated, and the input vibration and those on the workpiece and hand-arm system were measured. Ten human subjects participated in the experiment. The results demonstrate that VR gloves significantly reduced the vibrations at the palm, hand dorsum, and wrist. The grinding interface condition and hand feed force did not substantially affect glove effectiveness. The use of gloves slightly increased the workpiece resonant response, but the resonant response did not significantly affect glove effectiveness. This study concluded that the use of VR gloves can help control vibration exposures of workers performing grinding of handheld workpieces.

Adverse childhood experiences and police mental health.

Purpose ­: The purpose of this study is to examine cross-sectional associations between adverse childhood experiences (ACEs) and mental health among police officers. Design/methodology/approach ­: The sample was from the Buffalo Cardio-Metabolic Occupational Police Stress study data (132 male and 51 female officers). Standardized surveys were administered to participants. Regression coefficients were obtained from models adjusted for age, sex, race and alcohol intake. All statistical tests were performed using a statistical significance level at p < 0.05. Findings ­: Regression analyses showed significant positive associations between ACEs and mental health (Posttraumatic Stress Disorder [PTSD]: ß = 1.70, p < 0.001 and depressive symptoms: ß = 1.29, p < 0.001). Resiliency significantly modified the association between ACEs and PTSD. A positive and significant association was observed among officers with lower resiliency (ß = 2.65, p < 0.001). The association between ACEs and PTSD was stronger among male officers compared to females (ß = 2.66, p < 0.001 vs. ß = 0.59, p ≤ 0.248, respectively). Research limitations/implications ­: Child abuse and development of PTSD or depression could not be traced through time as this was a cross-sectional study. Recall bias may affect results. Practical implications ­: PTSD and depression associated with ACEs can affect the interpretation of threat and can exacerbate emotional regulation in officers. An inquiry should be expanded regarding work assignments of victimized officers, such as child exploitation and pornography investigation. Originality/value ­: There are few studies on ACEs and the mental health of police officers. The present study is among the first to associate multiple police mental health issues with ACEs.

The Feasibility and Impact of a Suicide Risk Screening Program in Rural Adult Primary Care: A Pilot Test of the Ask Suicide-Screening Questions Toolkit.

OBJECTIVE: The purpose of this study was to evaluate the feasibility and impact of a suicide risk screening program in a rural West Virginia primary care practice. METHODS: Patients presenting for routine and sick visits were asked to participate in electronic suicide risk screening using the Ask Suicide-Screening Questions tool; screen positive individuals were assessed with the Ask Suicide-Screening Questions Brief Suicide Safety Assessment. Screening program feasibility was evaluated by the proportion of patients consenting to participate, participant Ask Suicide-Screening Questions and Brief Suicide Safety Assessment completion rates, and response to a question asking whether primary care providers should ask about suicide. Screening impact was evaluated quasi-experimentally by comparing electronic medical record documentation of suicide risk screening, assessment, and risk determination in practice patients before and after implementing the screening program. RESULTS: Over half of the patients approached agreed to participate in a research study about suicide (N = 196; 57.7%). Feasibility of the screening program was demonstrated by the high completion rates for the Ask Suicide-Screening Questions (99.0%) and the Brief Suicide Safety Assessment (100.0%) among study participants. Additionally, 95.4% (N = 187) of participants agreed primary care providers should screen patients for suicide. Suicide screening rates rose significantly between the baseline and intervention phases (5.8% to 61.0%; X2 = 200.61, P < 0.001), as did suicide risk detection rates (0.7% to 6.2%; X2 = 12.58, P < 0.001). CONCLUSION: Suicide risk screening was feasible and well accepted by adult patients in rural primary care and has potential to improve suicide risk detection in this setting.