| 1. |
- Abrahamsson, Camilla, et al.
(författare)
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Aerosolized particulate matter from fragmentation of carbon nanotube-enhanced concrete
- 2023
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Ingår i: Abstracts from the 2022 Airmon-10 conference and the 2023 Inhaled Particles and NanOEH conference. - 2398-7316 .- 2398-7308. ; 67:Supplement_1, s. i94-i95
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Konferensbidrag (refereegranskat)abstract
- Construction and demolition workers are exposed to high levels of particulate matter (PM) from building materials throughout their working life. Although nano-enabled building materials (NEBMs) may improve the performance and functionality of buildings, concerns are being raised regarding health risks from occupational exposure to PM from NEBMs. In this work, an experimental set-up for integrated resuspension and characterization of PM from NEBMs was developed and tested using three types of concrete (low density, normal, high strength), each enhanced with Carbon Nanotubes (CNTs) at different concentrations (0, low, high). The performance of portable devices used in occupational exposure assessments (DustTrak and NanoTracer) was compared with stationary instruments and gravimetric filter techniques. 40-70% of the mass and 90-98% of the number of particles were within the respirable fraction, with primary modes at 150 nm and 2-3 µm. Addition of CNTs significantly decreased mean particle number concentrations (PNCs) across the entire characterized size range (7 nm - 20 µm) for low density concrete, whereas the opposite was the case for normal strength and high strength concrete. It was hypothesised that the concrete matrix primarily governs the PM formation, which is in turn modulated by CNT-matrix interactions either suppressing or supporting fragmentation during crushing. SEM imaging could display partially submerged CNTs protruding from concrete fragments. Fundamental interactions at the interface of the nanomaterial and the surrounding matrix needs to be investigated to determine how the PM generated from NEBMs differ from their non-nano counterparts and how to prevent future exposure during demolition.
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| 2. |
- Abrahamsson, Camilla, et al.
(författare)
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Characterization of airborne dust emissions from three types of crushed multi-walled carbon nanotube-enhanced concretes
- 2024
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Ingår i: NanoImpact. - : Elsevier B.V.. - 2452-0748. ; 34
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Tidskriftsartikel (refereegranskat)abstract
- Dispersing Multi-Walled Carbon Nanotubes (MWCNTs) into concrete at low (<1 wt% in cement) concentrations may improve concrete performance and properties and provide enhanced functionalities. When MWCNT-enhanced concrete is fragmented during remodelling or demolition, the stiff, fibrous and carcinogenic MWCNTs will, however, also be part of the respirable particulate matter released in the process. Consequently, systematic aerosolizing of crushed MWCNT-enhanced concretes in a controlled environment and measuring the properties of this aerosol can give valuable insights into the characteristics of the emissions such as concentrations, size range and morphology. These properties impact to which extent the emissions can be inhaled as well as where they are expected to deposit in the lung, which is critical to assess whether these materials might constitute a future health risk for construction and demolition workers. In this work, the impact from MWCNTs on aerosol characteristics was assessed for samples of three concrete types with various amounts of MWCNT, using a novel methodology based on the continuous drop method. MWCNT-enhanced concretes were crushed, aerosolized and the emitted particles were characterized with online and offline techniques. For light-weight porous concrete, the addition of MWCNT significantly reduced the respirable mass fraction (RESP) and particle number concentrations (PNC) across all size ranges (7 nm – 20 μm), indicating that MWCNTs dampened the fragmentation process by possibly reinforcing the microstructure of brittle concrete. For normal concrete, the opposite could be seen, where MWCNTs resulted in drastic increases in RESP and PNC, suggesting that the MWCNTs may be acting as defects in the concrete matrix, thus enhancing the fragmentation process. For the high strength concrete, the fragmentation decreased at the lowest MWCNT concentration, but increased again for the highest MWCNT concentration. All tested concrete types emitted <100 nm particles, regardless of CNT content. SEM imaging displayed CNTs protruding from concrete fragments, but no free fibres were detected.
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| 3. |
- Al-Rekabi, Zeinab, et al.
(författare)
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Uncovering the cytotoxic effects of air pollution with multi-modal imaging of in vitro respiratory models
- 2023
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Ingår i: Royal Society Open Science. - : Royal Society Publishing. - 2054-5703. ; 10:4
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Tidskriftsartikel (refereegranskat)abstract
- Annually, an estimated seven million deaths are linked to exposure to airborne pollutants. Despite extensive epidemiological evidence supporting clear associations between poor air quality and a range of short- and long-term health effects, there are considerable gaps in our understanding of the specific mechanisms by which pollutant exposure induces adverse biological responses at the cellular and tissue levels. The development of more complex, predictive, in vitro respiratory models, including two- and three-dimensional cell cultures, spheroids, organoids and tissue cultures, along with more realistic aerosol exposure systems, offers new opportunities to investigate the cytotoxic effects of airborne particulates under controlled laboratory conditions. Parallel advances in high-resolution microscopy have resulted in a range of in vitro imaging tools capable of visualizing and analysing biological systems across unprecedented scales of length, time and complexity. This article considers state-of-the-art in vitro respiratory models and aerosol exposure systems and how they can be interrogated using high-resolution microscopy techniques to investigate cell-pollutant interactions, from the uptake and trafficking of particles to structural and functional modification of subcellular organelles and cells. These data can provide a mechanistic basis from which to advance our understanding of the health effects of airborne particulate pollution and develop improved mitigation measures.
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| 4. |
- Berggren-Nylund, Rebecca, et al.
(författare)
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Effects of hypoxia on bronchial and alveolar epithelial cells linked to pathogenesis in chronic lung disorders
- 2023
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Ingår i: Frontiers in Physiology. - : Frontiers Media SA. - 1664-042X. ; 14, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Chronic lung disorders involve pathological alterations in the lung tissue with hypoxia as a consequence. Hypoxia may influence the release of inflammatory mediators and growth factors including vascular endothelial growth factor (VEGF) and prostaglandin (PG)E 2. The aim of this work was to investigate how hypoxia affects human lung epithelial cells in combination with profibrotic stimuli and its correlation to pathogenesis. Methods: Human bronchial (BEAS-2B) and alveolar (hAELVi) epithelial cells were exposed to either hypoxia (1% O 2) or normoxia (21% O 2) during 24 h, with or without transforming growth factor (TGF)-β1. mRNA expression of genes and proteins related to disease pathology were analysed with qPCR, ELISA or immunocytochemistry. Alterations in cell viability and metabolic activity were determined. Results: In BEAS-2B and hAELVi, hypoxia significantly dowregulated genes related to fibrosis, mitochondrial stress, oxidative stress, apoptosis and inflammation whereas VEGF receptor 2 increased. Hypoxia increased the expression of Tenascin-C, whereas both hypoxia and TGF-β1 stimuli increased the release of VEGF, IL-6, IL-8 and MCP-1 in BEAS-2B. In hAELVi, hypoxia reduced the release of fibroblast growth factor, epidermal growth factor, PGE 2, IL-6 and IL-8, whereas TGF-β1 stimulus significantly increased the release of PGE 2 and IL-6. TGF-β1 stimulated BEAS-2B cells showed a decreased release of VEGF-A and IL-8, while TGF-β1 stimulated hAELVi cells showed a decreased release of PGE 2 and IL-8 during hypoxia compared to normoxia. Metabolic activity was significantly increased by hypoxia in both epithelial cell types. Discussion: In conclusion, our data indicate that bronchial and alveolar epithelial cells respond differently to hypoxia and profibrotic stimuli. The bronchial epithelium appears more responsive to changes in oxygen levels and remodelling processes compared to the alveoli, suggesting that hypoxia may be a driver of pathogenesis in chronic lung disorders.
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| 5. |
- Franzén, Sara, et al.
(författare)
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Compositional tuning of gas-phase synthesized Pd–Cu nanoparticles
- 2023
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Ingår i: Nanoscale Advances. - 2516-0230. ; 5:22, s. 6069-6077
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Tidskriftsartikel (refereegranskat)abstract
- Bimetallic nanoparticles have gained significant attention in catalysis as potential alternatives to expensive catalysts based on noble metals. In this study, we investigate the compositional tuning of Pd–Cu bimetallic nanoparticles using a physical synthesis method called spark ablation. By utilizing pure and alloyed electrodes in different configurations, we demonstrate the ability to tailor the chemical composition of nanoparticles within the range of approximately 80 : 20 at% to 40 : 60 at% (Pd : Cu), measured using X-ray fluorescence (XRF) and transmission electron microscopy energy dispersive X-ray spectroscopy (TEM-EDXS). Time-resolved XRF measurements revealed a shift in composition throughout the ablation process, potentially influenced by material transfer between electrodes. Powder X-ray diffraction confirmed the predominantly fcc phase of the nanoparticles while high-resolution TEM and scanning TEM-EDXS confirmed the mixing of Pd and Cu within individual nanoparticles. X-ray photoelectron and absorption spectroscopy were used to analyze the outermost atomic layers of the nanoparticles, which is highly important for catalytic applications. Such comprehensive analyses offer insights into the formation and structure of bimetallic nanoparticles and pave the way for the development of efficient and affordable catalysts for various applications.
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| 6. |
- Gren, Louise, et al.
(författare)
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Lung function and self-rated symptoms in healthy volunteers after exposure to hydrotreated vegetable oil (HVO) exhaust with and without particles
- 2022
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Ingår i: Particle and Fibre Toxicology. - : Springer Science and Business Media LLC. - 1743-8977. ; 19:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Diesel engine exhaust causes adverse health effects. Meanwhile, the impact of renewable diesel exhaust, such as hydrotreated vegetable oil (HVO), on human health is less known. Nineteen healthy volunteers were exposed to HVO exhaust for 3 h in a chamber with a double-blind, randomized setup. Exposure scenarios comprised of HVO exhaust from two modern non-road vehicles with 1) no aftertreatment system ('HVOPM+NOx' PM1: 93 mu g-m(-3), EC: 54 mu g-m(-3), NO: 3.4 ppm, -NO2: 0.6 ppm), 2) an aftertreatment system containing a diesel oxidation catalyst and a diesel particulate filter ('HVONOx' PM1: similar to 1 mu g-m(-3), NO: 2.0 ppm, -NO2: 0.7 ppm) and 3) filtered air (FA) as control. The exposure concentrations were in line with current EU occupational exposure limits (OELs) of NO, -NO2, formaldehyde, polycyclic aromatic hydrocarbons (PAHs), and the future OEL (2023) of elemental carbon (EC). The effect on nasal patency, pulmonary function, and self-rated symptoms were assessed. Calculated predicted lung deposition of HVO exhaust particles was compared to data from an earlier diesel exhaust study. Results: The average total respiratory tract deposition of PM1 during -HVO(PM+ NO)x was 27 mu g-h(-1). The estimated deposition fraction of HVO PM1 was 40-50% higher compared to diesel exhaust PM1 from an older vehicle (earlier study), due to smaller particle sizes of the -HVOPM+ NOx exhaust. Compared to FA, exposure to -HVOPM+ NOx and -HVONOx caused higher incidence of self-reported symptoms (78%, 63%, respectively, vs. 28% for FA, p < 0.03). Especially, exposure to -HVOPM+ NOx showed 40-50% higher eye and throat irritation symptoms. Compared to FA, a decrement in nasal patency was found for the -HVONOx exposures (- 18.1, 95% CI: - 27.3 to - 8.8 L-min(-1), p < 0.001), and for the -HVOPM+ NOx (- 7.4 (- 15.6 to 0.8) L -min(-1), p = 0.08). Overall, no clinically significant change was indicated in the pulmonary function tests (spirometry, peak expiratory flow, forced oscillation technique). Conclusion: Short-term exposure to HVO exhaust concentrations corresponding to EU OELs for one workday did not cause adverse pulmonary function changes in healthy subjects. However, an increase in self-rated mild irritation symptoms, and mild decrease in nasal patency after both HVO exposures, may indicate irritative effects from exposure to HVO exhaust from modern non-road vehicles, with and without aftertreatment systems.
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| 7. |
- Janhäll, Sara, 1965-, et al.
(författare)
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Release of carbon nanotubes during combustion of polymer nanocomposites in a pilot-scale facility for waste incineration
- 2021
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Ingår i: NanoImpact. - : Elsevier BV. - 2452-0748. ; 24
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Tidskriftsartikel (refereegranskat)abstract
- Nanocomposites, formed by incorporating nanoparticles into a matrix of standard materials, are increasing on the market. Little focus has been directed towards safe disposal and recycling of these new materials even though the disposal has been identified as a phase of the products' life cycle with a high risk of uncontrolled emissions of nanomaterials. In this study, we investigate if the carbon nanotubes (CNTs), when used as a filler in two types of polymers, are fully destructed in a pilot-scale combustion unit designed to mimic the combustion under waste incineration. The two polymer nanocomposites studied, polycarbonate (PC) with CNT and high-density polyethylene (HDPE) with CNT, were incinerated at two temperatures where the lower temperature just about fulfilled the European waste incineration directive while the upper was chosen to be on the safe side of fulfilling the directive. Particles in the flue gas were sampled and analysed with online and offline instrumentation along with samples of the bottom ash. CNTs could be identified in the flue gas in all experiments, although present to a greater extent when the CNTs were introduced in PC as compared to in HDPE. In the case of using PC as polymer matrix, CNTs were identified in 3–10% of the analysed SEM images while for HDPE in only ~0.5% of the images. In the case of PC, the presence of CNTs decreased with increasing bed temperature (from 10% to 3% of the images). The CNTs identified were always in bundles, often coated with remnants of the polymer, forming particles of ~1–4 μm in diameter. No CNTs were identified in the bottom ash, likely explained by the difference in time when the bottom ash and fly ash are exposed to high temperatures (~hours compared to seconds) in the pilot facility. The results suggest that the residence time of the fly ash in the combustion zone is not long enough to allow full oxidation of the CNTs. Thus, the current regulation on waste incineration (requiring a residence time of the flue gas >850 °C during at least 2 s) may not be enough to obtain complete destruction of CNTs in polymer composites. Since several types of CNTs are known to be toxic, we stress the need for further investigation of the fate and toxicity of CNTs in waste treatment processes.
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| 8. |
- Jönsson, Linnéa, et al.
(författare)
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The effect of electrode composition on bimetallic AgAu nanoparticles produced by spark ablation
- 2024
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Ingår i: Journal of Aerosol Science. - 0021-8502. ; 177
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Tidskriftsartikel (refereegranskat)abstract
- A flexible way to generate bimetallic nanoparticles with high control of their composition is to use spark ablation of alloyed electrodes. It has been generally accepted and stated that particles produced using spark ablation of alloyed electrodes obtain the same chemical composition as the electrodes. However, we identify a lack of studies fully supporting the connection between electrode and particle composition, presented in a small literature survey. The aim of the study is, hence, to explore the validity of the statement by analysing the relation between alloyed electrodes and their resulting particle composition using three sets of AgAu electrodes containing Au and 25, 50, and 75 atomic % Ag, respectively. The resulting composition is thoroughly investigated using both single particle (scanning- and transmission electron microscopy) and ensemble particle techniques (inductive coupled plasma-mass spectroscopy, x-ray photoelectron spectroscopy, x-ray fluorescence, and optical measurements of surface plasmon resonance. We also investigate how sample size (e.g., the number of particles analysed) affects the reliability of the resulting sample mean. For single-particle measurements of a sample with a compositional standard deviation of a few atomic percentage points, a sample size of 20 particles is a good benchmark for obtaining reliable results of the sample mean. Furthermore, this article aims to challenge the practice in which the composition of nanoparticles is measured, presented, and interpreted, to improve and facilitate future research related to this topic. From the results of this study, it could be concluded that for the investigated Ag–Au material system, the particles obtained a composition very similar to the alloyed AgAu electrodes.
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| 9. |
- Kåredal, Monica, et al.
(författare)
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A quantitative LC-MS method to determine surface contamination of antineoplastic drugs by wipe sampling
- 2022
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Ingår i: Journal of Occupational and Environmental Hygiene. - : Informa UK Limited. - 1545-9624 .- 1545-9632. ; 19:1, s. 50-66
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Tidskriftsartikel (refereegranskat)abstract
- The main objective was to develop a wipe sampling test to measure surface contamination of the most frequently used antineoplastic drugs (ADs) in Swedish healthcare and, furthermore, to develop an analysis method sensitive enough to assess low levels of contamination. Two wipe sampling tests with separate sample processing methods assessing (i) cyclophosphamide (CP), ifosfamide (IF), 5-fluorouracil (5-FU), etoposide (ETO), gemcitabine (GEM) and cytarabine (CYT) (Wipe Test 1); and (ii) GEM, CYT and methotrexate (MTX) (Wipe Test 2), respectively, were developed by optimization of absorption and extraction efficiencies using different wipe tissue materials, tissue wetting solution, and extraction solvents. A fast liquid chromatography tandem mass spectrometry method was developed for simultaneous detection of the studied ADs. The limit of quantification for the method was between 0.04 to 2.4 ng/wipe sample (0.10 to 6.1 pg/cm2 for an area of 400 cm2) and at 50 ng/sample the within-day precision was between 1.3 and 15%, and the accuracy between 102 and 127%. Wipe Test 1 was applied in an assessment of cleaning efficiency of five different cleaning solutions (formic acid, water, sodium hydroxide, ethanol, and sodium dodecyl sulfate (SDS) for removal of ADs from surfaces made of stainless steel or plastic. For CP, IF, 5-FU, GEM, and CYT 92% of the AD were removed regardless of surface and cleaning solution. In conclusion, a user-friendly assessment method to measure low levels of seven ADs in the work environment was developed and validated. Assessment of the decontamination efficiency of cleaning solutions concerning removal of ADs from stainless steel showed that efficiencies differed depending on the AD with water being the least effective cleaning agent. The results suggests that a combination of different cleaning agents including detergent and a solution with an organic component would be optimal to efficiently remove the measured ADs from surfaces in the workplace.
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| 10. |
- Kåredal, Monica, et al.
(författare)
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Pilot study : External surface contamination of gemcitabine and 5-fluorouracil on drug packaging
- 2024
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Ingår i: Journal of oncology pharmacy practice. - : SAGE Publications. - 1078-1552 .- 1477-092X.
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Antineoplastic drugs (ADs) are commonly used pharmaceuticals for anticancer treatments. It has previously been shown that the external surface of drug vials frequently is contaminated with ADs. More than a decade ago methods to prevent occupational exposure were introduced by using plastic coverage of the glass vials or packing vials in a secondary plastic container. The aim of the pilot study was to determine contamination levels of ADs on different parts of AD packaging of two different commercially available drug vials on the Swedish market and to investigate the occurrence of cross contamination of ADs. Methods: Packagings of gemcitabine (GEM) and 5-fluorouracil (5-FU) were tested by wipe sampling. Five ADs; GEM, 5-FU, cyclophosphamide (CP), ifosfamide and etoposide were quantified using liquid chromatography mass spectrometry. Results: AD contaminations were detected in 69% and 60% of the GEM and 5-FU packaging samples. Highest levels, up to approximately 5 µg/sample, were observed on the glass vials. The protective shrink-wrap of 5-FU vials and the plastic container of GEM were contaminated with low levels of 5-FU and GEM, respectively, and furthermore the 5-FU vials with shrink-wrap were cross-contaminated with GEM. Cross-contamination of CP and GEM was detected on 5-FU vials with plastic shrink-wrap removed. Conclusions: External contamination of ADs are still present at primary drug packagings on the Swedish market. Protection of AD vials by plastic shrink-wrap or a secondary plastic container does not remove the external contamination levels completely. The presence of cross contamination of ADs on drug packagings was also observed.
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