Simulated gastric leachate of 3D printer metal-fill filaments induces cytotoxic effects in rat and human intestinal models.

Metals are used in 3-dimensional (3D) printer filaments in the manufacture of 3D printed objects. Exposure to the filaments, printed objects and emissions from printing may pose health risks from release of toxic metals. This study investigated the cytotoxicity of extruded 3D printer filament leachates in rat and human intestinal cells. Copper-, bronze-, and steel-fill extruded filaments were incubated in acidic media for 2 h. Leachates were adjusted to pH 7 and cells exposed for 4 or 24 h. Concentration- and time-dependent decreases in rat and human cell viability were observed using a colorimetric assay and confirmed by microscopy. Copper- and bronze-fill leachates were more cytotoxic than steel. Copper-fill leachates had the highest copper concentrations by ICP-MS. Exposure to CuSO4 resulted in concentration-dependent cytotoxicity in rat cells. The copper chelator bathocuproine disulphonate alleviated cytotoxicity of CuSO4 and copper-fill leachate, suggesting that copper ions have a role in the cytotoxicity. Hydrogen peroxide increased and glutathione decreased in rat cells exposed to copper-fill leachate, suggesting the formation of reactive oxygen species. Overall, our data indicate that metals released from the acidic exposure of print objects using metal-fill filaments, especially copper, are toxic to rat and human intestinal cells and additional studies are needed.

Time to recovery and its predictors among under five children in outpatient therapeutic feeding programme in Borena zone, Southern Ethiopia: a retrospective cohort study.

OBJECTIVES: This study aimed to assess the time to recovery and its predictors among 6-59 months aged children treated at an outpatient therapeutic feeding programme in Borena zone. DESIGN: A retrospective cohort study. SETTING: Facility based; 23 treatment sites included in this study. PARTICIPANTS: Among the cohorts of 601 children aged 6-59 months enrolled from July 2019 to June 2021, records of 590 children were selected using systematic random sampling. Transfers and incomplete records were excluded. PRIMARY AND SECONDARY OUTCOME MEASURES: Time to recovery was a main outcome while its predictors were secondary outcomes. RESULTS: The median recovery time was 49 days (95% CI=49 to 52) with a recovery rate of 79.8% (95% CI=76.4 to 83.0). Absence of comorbidity (adjusted HR, AHR=1.72, 95% CI=1.08 to 2.73), referral way by trained mothers on screening (AHR=1.91, 95% CI=1.25 to 2.91), new admission (AHR=1.59, 95% CI=1.05 to 2.41) and adequate Plumpy'Nut provision (AHR=2.10, 95% CI=1.72 to 2.56) were significantly associated with time to recovery. It is also found that being from a distance ≥30 min to treatment site lowers a chance of recovery by 27% (AHR=0.73, 95% CI=0.60 to 0.89). CONCLUSIONS: The findings showed that a time to recovery was within an acceptable range. Incidence of recovery is enhanced with early case detection, proper management, nearby service, new admissions, provision of adequate Plumpy'Nut and enabling mothers to screen their own children for acute malnutrition. However, we did not observe a statistically significant association among breastfeeding status, type of health facility, wasting type, vaccination and routine medications. Service providers should improve adherence to treatment protocols, defaulter tracing, community outreach and timely case identification.

Does quality of antenatal care influence antepartum stillbirth in Hossana City, South Ethiopia?

BACKGROUND: Antepartum stillbirth is a public health problem in a low-income country like Ethiopia. Quality antenatal care (ANC) is supposed to reduce the risk of many bad outcomes. Thus the main objective of this study was to identify the effect of quality antenatal care on antepartum stillbirth in Public health facilities of Hossana town Hadiya zone south Ethiopia. METHOD: About 1123 mothers with a gestational age of less than 16 weeks were identified and followed using an observational longitudinal study to determine whether the quality of ANC influences antepartum stillbirth or not. Standardized and pretested observation checklists and participants' interview questionnaires were employed to obtain the necessary information after getting both written and verbal consent from the concerned bodies and study participants. In this study, quality was measured by the process attributes of quality to measure the acceptable standard of quality of antenatal care. Women who received ≥75% of essential ANC services (from 1st-4th visit) were categorized under received good quality antenatal care. General estimating equation analysis was done to determine the effect of quality antenatal care on antepartum stillbirth. RESULT: A total of 121 (12.3%) 95% CI (10.3%, 14.5%) mothers who were observed during delivery had encountered antepartum stillbirth. In this study, the overall quality of antenatal care service that was provided in the whole visit (1st -4th) was 1230 (31.38%). Higher quality ANC decreases the odds of antepartum stillbirth by almost 81%, after controlling other factors (0.19 (AOR 0.19 at 95% CI; 0.088 to 0.435). There is a change in the odds of developing antepartum stillbirth as the level of education of mothers increases. Moreover, mothers with a history of preexisting hypertension were more like to have antepartum stillbirth AOR = 3.1, 95%CI (1.44, 6.77)]. CONCLUSION AND RECOMMENDATION: Therefore, having a good quality of ANC significantly reduces antepartum stillbirth. Strategies need to be developed on the problems identified to improve the quality of ANC and reduce antepartum stillbirth significantly.

Characterization of 3D printing filaments containing metal additives and their particulate emissions.

Polylactic acid (PLA) filaments are widely used in fused filament fabrication (FFF) processes (3D printing). Filament additives such as metallic particles incorporated into PLA to modify functional and aesthetic features of print objects are becoming increasingly popular. However, the identities and concentrations of low percentage and trace metals in these filaments have not been well described in either the literature or product safety information included with the product. We report the structures and concentrations of metals in selected Copperfill, Bronzefill and Steelfill filaments. We also report size-weighted number concentrations and size-weighted mass concentrations of particulate emissions as a function of print temperature for each filament. Particulate emissions were heterogenous in shape and size with airborne particles below 50 nm diameter dominating the size-weighted particle concentrations and larger particles (approximately 300 nm) dominating the mass weighted particle concentration. Results indicate that potential exposure to particles in the nano-size range increase when using print temperatures above 200o C. Because inhalation exposure to nanoparticles has been linked to adverse health outcomes, we suggest that using lower print temperatures for specific metal-fill filaments may reduce their operational hazard.

Human exposure to metals in consumer-focused fused filament fabrication (FFF)/ 3D printing processes.

Fused filament fabrication (FFF) or 3D printing is a growing technology used in industry, cottage industry and for consumer applications. Low-cost 3D printing devices have become increasingly popular among children and teens. Consequently, 3D printers are increasingly common in households, schools, and libraries. Because the operation of 3D printers is associated with the release of inhalable particles and volatile organic compounds (VOCs), there are concerns of possible health implications, particularly for use in schools and residential environments that may not have adequate ventilation such as classrooms bedrooms and garages, etc. Along with the growing consumer market for low-cost printers and printer pens, there is also an expanding market for a range of specialty filaments with additives such as inorganic colorants, metal particles and nanomaterials as well as metal-containing flame retardants, antioxidants, heat stabilizers and catalysts. Inhalation of particulate-associated metals may represent a health risk depending on both the metal and internal dose to the respiratory tract. Little has been reported, however, about the presence, speciation, and source of metals in the emissions; or likewise the effect of metals on emission processes and toxicological implications of these 3D printer generated emissions. This report evaluates various issues including the following: metals in feedstock with a focus on filament characteristics and function of metals; the effect of metals on the emissions and metals detected in emissions; printer emissions, particle formation, transport, and transformation; exposure and translation to internal dose; and potential toxicity on inhaled dose. Finally, data gaps and potential areas of future research are discussed within these contexts.