| 1. |
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| 2. |
- Cappellini, Francesca, et al.
(author)
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Dry Generation of CeO2 Nanoparticles and Deposition onto a Co-Culture of A549 and THP-1 Cells in Air-Liquid Interface-Dosimetry Considerations and Comparison to Submerged Exposure
- 2020
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In: Nanomaterials. - : MDPI AG. - 2079-4991. ; 10:4
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Journal article (peer-reviewed)abstract
- Relevant in vitro assays that can simulate exposure to nanoparticles (NPs) via inhalation are urgently needed. Presently, the most common method employed is to expose lung cells under submerged conditions, but the cellular responses to NPs under such conditions might differ from those observed at the more physiological air-liquid interface (ALI). The aim of this study was to investigate the cytotoxic and inflammatory potential of CeO2 NPs (NM-212) in a co-culture of A549 lung epithelial cells and differentiated THP-1 cells in both ALI and submerged conditions. Cellular dose was examined quantitatively using inductively coupled plasma mass spectrometry (ICP-MS). The role of serum and LPS-priming for IL-1 beta release was further tested in THP-1 cells in submerged exposure. An aerosol of CeO2 NPs was generated by using the PreciseInhale (R) system, and NPs were deposited on the co-culture using XposeALI (R). No or minor cytotoxicity and no increased release of inflammatory cytokines (IL-1 beta, IL-6, TNF alpha, MCP-1) were observed after exposure of the co-culture in ALI (max 5 mu g/cm(2)) or submerged (max 22 mu g/cm(2)) conditions. In contrast, CeO2 NPs cause clear IL-1 beta release in monocultures of macrophage-like THP-1, independent of the presence of serum and LPS-priming. This study demonstrates a useful approach for comparing effects at various in-vitro conditions.
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| 3. |
- Nordin, Susanna, et al.
(author)
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The physical environment, activity and interaction in residential care facilities for older people: a comparative case study
- 2017
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In: Scandinavian Journal of Caring Sciences. - : Wiley. - 0283-9318 .- 1471-6712. ; 31:4, s. 727-738
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Journal article (peer-reviewed)abstract
- The physical environment is of particular importance for supporting activities and interactions among older people living in residential care facilities (RCFs) who spend most of their time inside the facility. More knowledge is needed regarding the complex relationships between older people and environmental aspects in long-term care. The present study aimed to explore how the physical environment influences resident activities and interactions at two RCFs by using a mixed-method approach. Environmental assessments were conducted via the Swedish version of the Sheffield Care Environment Assessment Matrix (S-SCEAM), and resident activities, interactions and locations were assessed through an adapted version of the Dementia Care Mapping (DCM). The Observed Emotion Rating Scale (OERS) was used to assess residents’ affective states. Field notes and walk-along interviews were also used. Findings indicate that the design of the physical environment influenced the residents’ activities and interactions. Private apartments and dining areas showed high environmental quality at both RCFs, whereas the overall layout had lower quality. Safety was highly supported. Despite high environmental quality in general, several factors restricted resident activities. To optimise care for older people, the design process must clearly focus on accessible environments that provide options for residents to use the facility independently.
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| 4. |
- Sörqvist, Patrik, et al.
(author)
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The green halo : Mechanisms and limits of the eco-label effect
- 2015
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In: Food Quality and Preference. - : Elsevier BV. - 0950-3293 .- 1873-6343. ; 43, s. 1-9
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Journal article (peer-reviewed)abstract
- Consumers believe that “eco-labeled” products taste better, which, at least in part, may be an effect of the label. The purpose of the current series of experiments was to examine some mechanisms and limits of this eco-label effect. In Experiment 1, an eco-label effect of similar magnitude was found for taste ratings of both conventional and organic bananas. Experiment 2 showed eco-label effects for a wider range of judgmental dimensions (i.e., health, calories, vitamins/minerals, mental performance, and willingness to pay) and the effect was about the same in magnitude for judgments of grapes and raisins. Experiment 3, with water as the tasted product, found no eco-label effect on judgments of taste, calories and vitamins/minerals, but an effect on willingness to pay, judgments of health benefits and judgments of mental performance benefits. Experiments 2 and 3 also included questionnaires on social desirability traits, schizotypal traits and pro-environmental consumer traits. The last was the strongest predictor of the eco-label effect amongst the three. In all, the eco-label effect is a robust phenomenon, but depends on interactions between product type and judgmental dimension. Implications for several accounts of the effect are discussed.
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| 5. |
- Hedberg, Jonas, et al.
(author)
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Interactions between surfactants and silver nanoparticles of varying charge
- 2012
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In: Journal of Colloid and Interface Science. - Amsterdam : Elsevier. - 0021-9797 .- 1095-7103. ; 369:1, s. 193-201
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Journal article (peer-reviewed)abstract
- The interaction between silvernanoparticles (Ag NPs) of different surface charge and surfactants relevant to the laundry cycle has been investigated to understand changes in speciation, both in and during transport from the washing machine. Ag NPs were synthesized to exhibit either a positive or a negative surface charge in solution conditions relevant for the laundry cycle (pH 10 and pH 7). These particles were characterized in terms of size and surface charge and compared to commercially laser ablated Ag NPs. The surfactants included anionic sodium dodecylbenzenesulfonate (LAS), cationic dodecyltrimethylammoniumchloride (DTAC) and nonionic Berol 266 (Berol). Surfactant–Ag NP interactions were studied by means of dynamic light scattering, Raman spectroscopy, zeta potential, and Quartz Crystal Microbalance. Mixed bilayers of CTAB and LAS were formed through a co-operative adsorption process on positively charged Ag NPs with pre-adsorbed CTAB, resulting in charge reversal from positive to negative zeta potentials. Adsorption of DTAC on negatively charged synthesized Ag NPs and negatively charged commercial Ag NPs resulted in bilayer formation and charge reversal. Weak interactions were observed for nonionic Berol with all Ag NPs via hydrophobic interactions, which resulted in decreased zeta potentials for Berol concentrations above its critical micelle concentration. Differences in particle size were essentially not affected by surfactant adsorption, as the surfactant layer thicknesses did not exceed more than a few nanometers. The surfactant interaction with the Ag NP surface was shown to be reversible, an observation of particular importance for hazard and environmental risk assessments.
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| 6. |
- Hedberg, Jonas, et al.
(author)
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Sequential Studies of Silver Released from Silver Nanoparticles in Aqueous Media Simulating Sweat, Laundry Detergent Solutions and Surface Water
- 2014
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In: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 48:13, s. 7314-7322
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Journal article (peer-reviewed)abstract
- From an increased use of silver nanoparticles (Ag NPs) as an antibacterial in consumer products follows a need to assess the environmental interaction and fate of their possible dispersion and release of silver. This study aims to elucidate an exposure scenario of the Ag NPs potentially released from, for example, impregnated clothing by assessing the release of silver and changes in particle properties in sequential contact with synthetic sweat, laundry detergent solutions, and freshwater, simulating a possible transport path through different aquatic media. The release of ionic silver is addressed from a water chemical perspective, compared with important particle and surface characteristics. Released amounts of silver in the sequential exposures were significantly lower, approximately a factor of 2, than the sum of each separate exposure. Particle characteristics such as speciation (both of Ag ionic species and at the Ag NP surface) influenced the release of soluble silver species present on the surface, thereby increasing the total silver release in the separate exposures compared with sequential immersions. The particle stability had no drastic impact on the silver release as most of the Ag NPs were unstable in solution. The silver release was also influenced by a lower pH (increased release of silver), and cotransported zeolites (reduced silver in solution).
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| 7. |
- Hedberg, Yolanda, et al.
(author)
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Chromium-protein complexation studies by adsorptive cathodic stripping voltammetry and MALDI-TOF-MS
- 2012
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In: Journal of Applied Electrochemistry. - : Springer Science and Business Media LLC. - 0021-891X .- 1572-8838. ; 42:5, s. 349-358
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Journal article (peer-reviewed)abstract
- A methodology using stripping voltammetry has been elaborated to enable sensitive and reliable protein-chromium complexation measurements. Disturbing effects caused by adsorption of proteins on the mercury electrode were addressed. At low concentrations of proteins (< 60-85 nM), chromium-protein complexation measurements were possible. Chromium(VI) complexation was quantitatively determined using differently sized, charged, and structured proteins: serum albumin (human and bovine), lysozyme, and mucin. Generated results showed a strong relation between complexation and protein size, concentration, and the number of amino acids per protein mass. Complexation increased nonlinearly with increasing protein concentrations. The nature of this complexation was based on weak interactions judged from combined results with MALDI-TOF-MS and adsorptive cathodic stripping voltammetry.
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| 8. |
- Hedberg, Yolanda, et al.
(author)
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Correlation between surface physicochemical properties and the release of iron from stainless steel AISI 304 in biological media
- 2014
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In: Colloids and Surfaces B. - : Elsevier BV. - 0927-7765 .- 1873-4367. ; 122, s. 216-222
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Journal article (peer-reviewed)abstract
- Stainless steel is widely used in biological environments, for example as implant material or in food applications, where adsorption-controlled ligand-induced metal release is of importance from a corrosion, health, and food safety perspective. The objective of this study was to elucidate potential correlations between surface energy and wettability of stainless steel surfaces and the release of iron in complexing biological media. This was accomplished by studying changes in surface energies calculated from contact angle measurements, surface oxide composition (X-ray photoelectron spectroscopy), and released iron (graphite furnace atomic absorption spectroscopy) for stainless steel grade AISI 304 immersed in fluids containing bovine serum albumin or citric acid, and non-complexing fluids such as NaCl, NaOH, and HNO3. It was shown that the surface wettability and polar surface energy components were all influenced by adventitious atmospheric carbon (surface contamination of low molecular weight), rather than differences in surface oxide composition in non-complexing solutions. Adsorption of both BSA and citrate, which resulted in ligand-induced metal release, strongly influenced the wettability and the surface energy, and correlated well with the measured released amount of iron.
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| 9. |
- Hedberg, Yolanda, 1985-, et al.
(author)
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Interaction of Albumin and Fibrinogen with Stainless Steel : Influence of Sequential Exposure and Protein Aggregation on Metal Release and Corrosion Resistance
- 2017
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In: Corrosion. - : NATL ASSOC CORROSION ENG. - 0010-9312 .- 1938-159X. ; 73:12
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Journal article (peer-reviewed)abstract
- Corrosion and metal release mechanisms of the biomedical stainless steel grade Type 316L are at human-relevant biological conditions not fully understood. This study focuses on its corrosion properties and release of iron (Fe), chromium (Cr), manganese (Mn), and nickel (Ni) into simulated physiological solutions at pH 7.4 in the presence of proteins. Parallel studies were performed on stainless steel Type 303 containing a substantial amount of MnS inclusions. Metal release studies were performed in phosphate buffered saline (PBS) for 4 h and 24 h at 37 degrees C with or without different concentrations of bovine serum albumin (BSA), fibrinogen from bovine plasma (Fbn), or mixtures of the same. Studies were in addition performed after 1, 4, 6, and 24 h in solutions that were partially replenished after 5 h in order to investigate whether any Vroman effect (exchange of adsorbed proteins by proteins of higher binding affinity) could influence the extent of released metals in solution. This was performed at physiological concentrations of BSA (40 g/L) and Fbn (2.67 g/L) in PBS, and for reference solutions of PBS, PBS with 40 g/L BSA, and PBS with 2.67 g/L Fbn. Changes in open-circuit potential and linear polarization resistance were investigated for the same conditions. After exposure, the exposed surfaces were rinsed and investigated ex situ by means of x-ray photoelectron spectroscopy and infrared reflection absorption spectroscopy. Metal-protein complexation-induced metal release mechanisms were found to be most pronounced for Type 316L and the release of Fe, Cr, and Ni. Fibrinogen adsorbed differently onto Type 303 (thicker conformation of adsorbed proteins) as compared with Type 316L and occasionally induced corrosion events for Type 303. Mn was mostly released from inclusions present in the Type 303 alloy, most probably via non-electrochemical mechanisms. A Vroman effect was observed for both grades. A significant extent of precipitation of metal-rich protein aggregates influenced the metal release measurements in solution and resulted in an underestimation of the total amount of released metals from the stainless steel grades.
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| 10. |
- Hedberg, Yolanda S., et al.
(author)
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Can Cobalt(II) and Chromium(III) ions released from joint prostheses influence the friction coefficient?
- 2015
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In: ACS Biomaterial Science and Engineering. - : American Chemical Society (ACS). - 2373-9878. ; 1:8, s. 617-620
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Journal article (peer-reviewed)abstract
- Cobalt chromium molybdenum alloys (CoCrMo) are commonly used as articulating components in joint prostheses. In this tribocorrosive environment, wear debris and metal ionic species are released and interact with proteins, possibly resulting in protein aggregation. This study aimed to investigate whether this could have an effect on the friction coefficient in a typical material couple, namely CoCrMo-on-polyethylene. It was confirmed that both Co(II) and Cr(III) ions, and their combination, at concentrations relevant for the metal release situation, resulted in protein aggregation and its concomitant precipitation, which increased the friction coefficient. Future studies should identify the clinical importance of these findings.
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| 11. |
- Hedberg, Yolanda S., et al.
(author)
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Electrochemical surface oxide characteristics of metal nanoparticles (Mn, Cu and Al) and the relation to toxicity
- 2016
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In: Electrochimica Acta. - : Elsevier BV. - 0013-4686 .- 1873-3859. ; 212, s. 360-371
-
Journal article (peer-reviewed)abstract
- Most metal nanoparticles (NPs), except noble metal NPs, rapidly form a thin surface oxide in ambient conditions. The protective properties of these oxides improve or worsen depending on the environment, e.g., the human lung. Several properties, including the chemical/electrochemical stability and defect density, determine the capacity of these surface oxides to hinder the bulk metal from further oxidation (corrosion). The aim of this study was to investigate whether electrochemical surface oxide characterization of non-functionalized base metal NPs of different characteristics (Al, Mn and Cu) can assist in understanding their bioaccessibility (metal release) in cell media (DMEM+) and their cytotoxic properties following exposure in lung epithelial (A549) cells. The composition and valence states of surface oxides of metal NPs and their electrochemical activity were investigated using an electrochemical technique based on a graphite paste electrode to perform cyclic voltammetry in buffer solutions and open circuit potential measurements in DMEM+. The electrochemical surface oxide characterization was complemented and verified by Raman spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The open circuit potential trends in DMEM+ correlated well with metal release results in the same solution, and provided information on the kinetics of oxide dissolution in the case of Cu NPs. Extensive particle agglomeration in cell medium (DMEM+) was observed by means of photon-cross correlation spectroscopy for all metal NPs, with sedimentation taking place very quickly. As a consequence, measurements of the real dose of added non-functionalized metal NPs to cell cultures for cytotoxicity testing from a sonicated stock solution were shown necessary. The cytotoxic response was found to be strongly correlated to changes in physico-chemical and electrochemical properties of the surface oxides of the metal NPs, the most potent being Cu NPs, followed by Mn NPs. No cytotoxicity was observed for Al NPs. The electrochemical surface oxide characterization corresponded well with other tools commonly used for nanotoxicological characterization and provided additional information.
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| 12. |
- Hedberg, Yolanda, et al.
(author)
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Surface-protein interactions on different stainless steel grades : effects of protein adsorption, surface changes and metal release
- 2013
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In: Journal of materials science. Materials in medicine. - : Springer Science and Business Media LLC. - 0957-4530 .- 1573-4838. ; 24:4, s. 1015-1033
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Journal article (peer-reviewed)abstract
- Implantation using stainless steels (SS) is an example where an understanding of protein-induced metal release from SS is important when assessing potential toxicological risks. Here, the protein-induced metal release was investigated for austenitic (AISI 304, 310, and 316L), ferritic (AISI 430), and duplex (AISI 2205) grades in a phosphate buffered saline (PBS, pH 7.4) solution containing either bovine serum albumin (BSA) or lysozyme (LSZ). The results show that both BSA and LSZ induce a significant enrichment of chromium in the surface oxide of all stainless steel grades. Both proteins induced an enhanced extent of released iron, chromium, nickel and manganese, very significant in the case of BSA (up to 40-fold increase), whereas both proteins reduced the corrosion resistance of SS, with the reverse situation for iron metal (reduced corrosion rates and reduced metal release in the presence of proteins). A full monolayer coverage is necessary to induce the effects observed.
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| 13. |
- Herting, Gunilla, 1975-, et al.
(author)
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A novel method to assess mass loss of aluminium in concrete
- 2018
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In: Materials and corrosion - Werkstoffe und Korrosion. - : John Wiley & Sons. - 0947-5117 .- 1521-4176. ; 69:12, s. 1811-1814
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Journal article (peer-reviewed)abstract
- A novel pickling procedure for aluminium is elaborated for successful removal of corrosion products on aluminium embedded and exposed in concrete, allowing subsequent mass loss evaluation. The current recommended standard procedures for mass loss evaluation of aluminium are not sufficiently effective, either leaving significant amounts of concrete and corrosion products on the aluminium surfaces after pickling, or containing hazardous chemicals. Removal of both concrete and corrosion products from the aluminium surfaces require a stepwise combination of an aqueous glycine solution, nitric acid at elevated temperature and careful manual removal of adherent concrete.
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| 14. |
- Lowe, Troy A., et al.
(author)
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Chemical Speciation Measurements of Silver Ions in Alkaline Carbonate Electrolytes Using Differential Pulse Stripping Voltammetry on Glassy Carbon Compared With Ion Selective Electrode Measurements
- 2013
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In: International Journal of Electrochemical Science. - 1452-3981. ; 8:3, s. 3851-3865
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Journal article (peer-reviewed)abstract
- Given the increasing incorporation of silver nanoparticles as an antibacterial additive in washing machines and textiles, sensitive methods for accurate determination of Ag+ ions in laundry relevant electrolytes (alkaline carbonate) are required. The most widely reported method, the silver ion selective electrode (ISE), lacked sensitivity and accuracy and was affected by the concentration of Na2CO3 in solution. Differential pulse stripping voltammetry (DPSV) on glassy carbon electrodes (GCE) was therefore investigated as an alternative technique. Surface preparation of the GCE surface was essential and a suitable procedure was developed. A linear response was observed from 0 to 180 mg L-1 with a lower detection limit of 500 ng L-1 (5 nM). DPSV was shown to be significantly more sensitive and accurate in determining the Ag+ activity than the silver ISE technique, particularly below 200 nM.
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| 15. |
- Lundin, Maria, et al.
(author)
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Adsorption and protein-induced metal release from chromium metal and stainless steel
- 2012
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In: Journal of Colloid and Interface Science. - : Elsevier BV. - 0021-9797 .- 1095-7103. ; 366:1, s. 155-164
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Journal article (peer-reviewed)abstract
- A research effort is undertaken to understand the mechanism of metal release from, e.g., inhaled metal particles or metal implants in the presence of proteins. The effect of protein adsorption on the metal release process from oxidized chromium metal surfaces and stainless steel surfaces was therefore examined by quartz crystal microbalance with energy dissipation monitoring (QCM-D) and graphite furnace atomic absorption spectroscopy (GFAAS). Differently charged and sized proteins, relevant for the inhalation and dermal exposure route were chosen including human and bovine serum albumin (HSA, BSA), mucin (BSM), and lysozyme (LYS). The results show that all proteins have high affinities for chromium and stainless steel (AISI 316) when deposited from solutions at pH 4 and at pH 7.4 where the protein adsorbed amount was very similar. Adsorption of albumin and mucin was substantially higher at pH 4 compared to pH 7.4 with approximately monolayer coverage at pH 7.4, whereas lysozyme adsorbed in multilayers at both investigated pH. The protein-surface interaction was strong since proteins were irreversibly adsorbed with respect to rinsing. Due to the passive nature of chromium and stainless steel (AISI 316) surfaces, very low metal release concentrations from the QCM metal surfaces in the presence of proteins were obtained on the time scale of the adsorption experiment. Therefore, metal release studies from massive metal sheets in contact with protein solutions were carried out in parallel. The presence of proteins increased the extent of metals released for chromium metal and stainless steel grades of different microstructure and alloy content, all with passive chromium(III)-rich surface oxides, such as QCM (AISI 316), ferritic (AISI 430), austentic (AISI 304, 316L), and duplex (LDX 2205).
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| 16. |
- Nielsen, Maria, et al.
(author)
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Nanomaterials in the European chemicals legislation-methodological challenges for registration and environmental safety assessment
- 2021
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In: Environmental Science: Nano. - : Royal Society of Chemistry. - 2051-8153 .- 2051-8161. ; 8:3, s. 731-747
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Journal article (peer-reviewed)abstract
- In the European Union the Annexes of its chemical legislation (REACH) were revised and now clarify the technical data requirements for nanomaterials (NMs). These new provisions, effective from January 1, 2020, introduce requirements for manufacturers, importers and downstream users regarding registration and safety assessment of NMs. This study aims to assess the availability and suitability of methods needed to comply with the new regulatory provisions on NMs for physico-chemical characterisation and environmental fate and effects. The scientific literature and relevant test guideline frameworks were reviewed to identify applicable methods. These were subsequently evaluated and categorised as either: 'internationally accepted test guideline or standard (TGS)', 'internationally accepted test guideline or standard under development (TGSUD)', 'established as standard methods in scientific literature (SCI)', 'other methods and/or more research needed (O)' or 'no method (N)'. We find that 80% of the information requirements and a bit more than 40% of the waiving criteria in the new REACH Annexes are supported by methods that are available as TGS, TGSUD or SCI. Most of the relevant methods in the scientific literature are included in recent OECD guidance documents or ECHA guidance. We recommend that a targeted effort is made to develop protocols and guidelines for methods to determine NM adsorption/desorption, degradation, exposure scenarios and ability to cross biological membranes. Here methods to fulfil the information requirements and waiving criteria are currently lacking. Furthermore, we recommend that increasing attention is directed towards regulatory reliability and relevance of the information that is submitted by the registrants.
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| 17. |
- Nordanstig, Joakim, et al.
(author)
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Mortality with Paclitaxel-Coated Devices in Peripheral Artery Disease.
- 2020
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In: The New England journal of medicine. - : Massachusetts Medical Society. - 1533-4406 .- 0028-4793. ; 383, s. 2538-46
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Journal article (peer-reviewed)abstract
- The results of a recent meta-analysis aroused concern about an increased risk of death associated with the use of paclitaxel-coated angioplasty balloons and stents in lower-limb endovascular interventions for symptomatic peripheral artery disease.We conducted an unplanned interim analysis of data from a multicenter, randomized, open-label, registry-based clinical trial. At the time of the analysis, 2289 patients had been randomly assigned to treatment with drug-coated devices (the drug-coated-device group, 1149 patients) or treatment with uncoated devices (the uncoated-device group, 1140 patients). Randomization was stratified according to disease severity on the basis of whether patients had chronic limb-threatening ischemia (1480 patients) or intermittent claudication (809 patients). The single end point for this interim analysis was all-cause mortality.No patients were lost to follow-up. Paclitaxel was used as the coating agent for all the drug-coated devices. During a mean follow-up of 2.49 years, 574 patients died, including 293 patients (25.5%) in the drug-coated-device group and 281 patients (24.6%) in the uncoated-device group (hazard ratio, 1.06; 95% confidence interval, 0.92 to 1.22). At 1 year, all-cause mortality was 10.2% (117 patients) in the drug-coated-device group and 9.9% (113 patients) in the uncoated-device group. During the entire follow-up period, there was no significant difference in the incidence of death between the treatment groups among patients with chronic limb-threatening ischemia (33.4% [249 patients] in the drug-coated-device group and 33.1% [243 patients] in the uncoated-device group) or among those with intermittent claudication (10.9% [44 patients] and 9.4% [38 patients], respectively).In this randomized trial in which patients with peripheral artery disease received treatment with paclitaxel-coated or uncoated endovascular devices, the results of an unplanned interim analysis of all-cause mortality did not show a difference between the groups in the incidence of death during 1 to 4 years of follow-up. (Funded by the Swedish Research Council and others; ClinicalTrials.gov number, NCT02051088.).
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| 18. |
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| 19. |
- Shi, J., et al.
(author)
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Hemolytic properties of synthetic nano- and porous silica particles : The effect of surface properties and the protection by the plasma corona
- 2012
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In: Acta Biomaterialia. - : Elsevier BV. - 1742-7061 .- 1878-7568. ; 8:9, s. 3478-3490
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Journal article (peer-reviewed)abstract
- Novel silica materials incorporating nanotechnology are promising materials for biomedical applications, but their novel properties may also bring unforeseen behavior in biological systems. Micro-size silica is well documented to induce hemolysis, but little is known about the hemolytic activities of nanostructured silica materials. In this study, the hemolytic properties of synthetic amorphous silica nanoparticles with primary sizes of 7-14 nm (hydrophilic vs. hydrophobic), 5-15 nm, 20 nm and 50 nm, and model meso/macroporous silica particles with pore diameters of 40 nm and 170 nm are investigated. A crystalline silica sample (0.5-10 ÎŒm) is included for benchmarking purposes. Special emphasis is given to investigations of how the temperature and solution complexity (solvent, plasma), as well as the physicochemical properties (such as size, surface charge, hydrophobicity and other surface properties), link to the hemolytic activities of these particles. Results suggests the potential importance of small size and large external surface area, as well as surface charge/structure, in the hemolysis of silica particles. Furthermore, a significant correlation is observed between the hemolytic profile of red blood cells and the cytotoxicity profile of human promyelocytic leukemia cells (HL-60) induced by nano- and porous silica particles, suggesting a potential universal mechanism of action. Importantly, the results generated suggest that the protective effect of plasma towards silica nanoparticle-induced hemolysis as well as cytotoxicity is primarily due to the protein/lipid layer shielding the silica particle surface. These results will assist the rational design of hemocompatible silica particles for biomedical applications.
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| 20. |
- Skoglund, Sara, et al.
(author)
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Effect of Laundry Surfactants on Surface Charge and Colloidal Stability of Silver Nanoparticles
- 2013
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In: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 29:28, s. 8882-8891
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Journal article (peer-reviewed)abstract
- The stability of silver nanoparticles (Ag NPs) potentially released from clothing during a laundry cycle and their interactions with laundry-relevant surfactants [anionic (LAS), cationic (DTAC), and nonionic (Berol)] have been investigated. Surface interactions between Ag NPs and surfactants influence their speciation and stability. In the absence of surfactants as well as in the presence of LAS, the negatively charged Ag NPs were stable in solution for more than 1 day. At low DTAC concentrations (<= 1 mM), DTAC-Ag NP interactions resulted in charge neutralization and formation of agglomerates. The surface charge of the particles became positive at higher concentrations due to a bilayer type formation of DTAC that prevents from agglomeration due to repulsive electrostatic forces between the positively charged colloids. The adsorption of Berol was enhanced when above its critical micelle concentration (cmc). This resulted in a surface charge dose to zero and subsequent agglomeration. Extended DLVO theory calculations were in compliance with observed findings. The stability of the Ag NPs was shown to depend on the charge and concentration of the adsorbed surfactants. Such knowledge is important as it may influence the subsequent transport of Ag NPs through different chemical transients and thus their potential bioavailability and toxicity.
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| 21. |
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