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| 2. |
- Chang, Tingru, et al.
(författare)
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A novel methodology to study antimicrobial properties of high-touch surfaces used for indoor hygiene applications-A study on Cu metal
- 2021
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 16:2
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Tidskriftsartikel (refereegranskat)abstract
- Metal-based high-touch surfaces used for indoor applications such as doorknobs, light switches, handles and desks need to remain their antimicrobial properties even when tarnished or degraded. A novel laboratory methodology of relevance for indoor atmospheric conditions and fingerprint contact has therefore been elaborated for combined studies of both tarnishing/corrosion and antimicrobial properties of such high-touch surfaces. Cu metal was used as a benchmark material. The protocol includes pre-tarnishing/corrosion of the high touch surface for different time periods in a climatic chamber at repeated dry/wet conditions and artificial sweat deposition followed by the introduction of bacteria onto the surfaces via artificial sweat droplets. This methodology provides a more realistic and reproducible approach compared with other reported procedures to determine the antimicrobial efficiency of high-touch surfaces. It provides further a possibility to link the antimicrobial characteristics to physical and chemical properties such as surface composition, chemical reactivity, tarnishing/corrosion, surface roughness and surface wettability. The results elucidate that bacteria interactions as well as differences in extent of tarnishing can alter the physical properties (e.g. surface wettability, surface roughness) as well as the extent of metal release. The results clearly elucidate the importance to consider changes in chemical and physical properties of indoor hygiene surfaces when assessing their antimicrobial properties.
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| 3. |
- Chang, Tingru, et al.
(författare)
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The interplay between atmospheric corrosion and antimicrobial efficiency of Cu and Cu5Zn5Al1Sn during simulated high-touch conditions
- 2021
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Ingår i: Corrosion Science. - : Elsevier BV. - 0010-938X .- 1879-0496. ; 185
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Tidskriftsartikel (refereegranskat)abstract
- The interplay between atmospheric corrosion and antimicrobial efficiency of bare Cu and Cu5Zn5Al1Sn was studied upon exposures simulating high-touch surface conditions. The survival of the bacteria Bacillus subtilis during surface contact with Cu and Cu5Zn5Al1Sn was examined under different degrees of surface oxidation, tarnishing, wettability and copper ion release. Depending on surface conditions complete bacteria inhibition was obtained within 4 min on Cu and within 6-10 min on Cu5Zn5Al1Sn. The antibacterial efficiency increases slightly with copper release rate and is governed by complex interactions between the corroded metal surface, bacteria and extracellular polymeric substances produced by the bacteria.
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| 6. |
- Fazlinovic, Sanin, et al.
(författare)
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Outcome and survival after open heart surgery for adults with congenital heart disease - a single center experience
- 2021
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Ingår i: Scandinavian Cardiovascular Journal. - : Informa UK Limited. - 1401-7431 .- 1651-2006. ; 55:6, s. 345-353
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Tidskriftsartikel (refereegranskat)abstract
- Introduction. Congenital heart disease (CHD) is the most common type of birth defect today. The adult congenital heart disease (ACHD) population is constantly growing and becoming older and more patients require cardiac surgery. The objective of this study was to review the surgical outcome of the open heart procedures performed on ACHD patients in the last 10 years at Sahlgrenska University Hospital (SUH) through a retrospective descriptive cohort study. Methods. A retrospective data collection was performed for 421 patients who underwent a total of 439 surgical procedures between 2009 and 2018 at the Cardiothoracic department in SUH. The primary outcomes were early (<30 days) and late survival. Secondary outcomes were postoperative complications and independent risk factors for postoperative complications. Results. 30-day mortality was 1.9%. Long-term survival after 3, 5 and 10 years were 96% +/- 1, 94.3% +/- 1.3 and 92.4% +/- 1.8. 82 major complications occurred after 46 procedures (11.6%). The most common major complication was re-exploration due to hemorrhage. Risk factors for major complications were acute surgery and prolonged extracorporeal circulation time. 173 minor complications occurred after 90 procedures (22.5%). The most common minor complication was prolonged intensive care unit stay (>48 h). Conclusion. This study presents satisfactory early and midterm survival. The survival and frequency of major postoperative complications are well in line with what other studies have presented. Patients undergoing resternotomies had no increased risk for mortality or postoperative complications.
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| 7. |
- Ferraris, M., et al.
(författare)
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Antibacterial silver nanocluster/silica composite coatings on stainless steel
- 2017
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Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 396, s. 1546-1555
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Tidskriftsartikel (refereegranskat)abstract
- A coating made of silver nanocluster/silica composites has been deposited, via a radio frequency (RF) co-sputtering technique, for the first time onto stainless steel (AISI 304L) with the aim to improve its antibacterial properties. Different thermal treatments after coating deposition have been applied in order to optimize the coating adhesion, cohesion and its antibacterial properties. Its applicability has been investigated at realistic conditions in a cheese production plant. The physico-chemical characteristics of the coatings have been analyzed by means of different bulk and surface analytical techniques. Field emission scanning electron microscopy (FESEM), X-ray Photoelectron Spectroscopy (XPS), contact angle measurements and atomic force microscopy (AFM) were employed to assess coating morphology, composition, surface roughness, wetting properties, size and local distribution of the nanoparticles within the coating. Tape tests were used to determine the adhesion/cohesion properties of the coating. The amount and time-dependence of released silver in solutions of acetic acid, artificial water, artificial tap water and artificial milk were determined by means of Atomic Absorption Spectroscopy (AAS). The antibacterial effect of the coating was evaluated at different experimental conditions using a standard bacterial strain of Staphylococcus aureus in compliance with National Committee for Clinical Laboratory Standards (NCCLS) and AATCC 147 standards. The Ahearn test was performed to measure the adhesion of bacteria to the coated stainless steel surface compared with a control surface. The antibacterial coating retained its antibacterial activity after thermal treatment up to 450 °C and after soaking in common cleaning products for stainless steel surfaces used for e.g. food applications. The antibacterial capacity of the coating remained at high levels for 1-5 days, and showed a good capacity to reduce the adhesion of bacteria up to 30 days. Only a few percent of silver in the coating was released into acetic acid, even after 10 days of exposure at 40 °C. Most silver (> 90%) remained also in the coating even after 240 h of continuous exposure. Similar observations were made after repeated exposure at 100 °C. Very low levels of released silver in solution were observed in artificial milk. No release of silver nanoparticles was observed either in synthetic tap water or in artificial milk at given conditions. The coating further displayed good antibacterial properties also when tested during working conditions in a cheese production plant.
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| 8. |
- Ferraris, Sara, et al.
(författare)
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Chemical, mechanical and antibacterial properties of silver nanocluster/silica composite coated textiles for safety systems and aerospace applications
- 2014
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 317, s. 131-139
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Tidskriftsartikel (refereegranskat)abstract
- This work describes the chemical, mechanical and antibacterial properties of a novel silver nanocluster/silica composite coating, obtained by sputtering, on textiles for use in nuclear bacteriological and chemical (NBC) protection suites and for aerospace applications.The properties of the coated textiles were analyzed in terms of surface morphology, silver concentration and silver release in artificial sweat and synthetic tap water, respectively. No release of silver nanoparticles was observed at given conditions.The water repellency, permeability, flammability and mechanical resistance of the textiles before and after sputtering demonstrated that the textile properties were not negatively affected by the coating.The antibacterial effect was evaluated at different experimental conditions using a standard bacterial strain of Staphylococcus aureus and compared with the behavior of uncoated textiles.The coating process conferred all textiles a good antibacterial activity. Optimal deposition conditions were elaborated to obtain sufficient antibacterial action without altering the aesthetical appearance of the textiles.The antibacterial coating retained its antibacterial activity after one cycle in a washing machine only for the Nylon based textile.
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| 9. |
- Hedberg, Jonas, 1979-, et al.
(författare)
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In the Search for Nanospecific Effects of Dissolution of Metallic Nanoparticles at Freshwater-Like Conditions : A Critical Review
- 2019
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 53:8, s. 4030-4044
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge on relations between particle properties and dissolution/transformation characteristics of metal and metal oxide nanoparticles (NPs) in freshwater is important for risk assessment and product development. This critical review aims to elucidate nanospecific effects on dissolution of metallic NPs in freshwater and similar media. Dissolution rate constants are compiled and analyzed for NPs of silver (Ag), copper (Cu), copper oxide/hydroxide (CuO, Cu(OH) 2 ), zinc oxide (ZnO), manganese (Mn), and aluminum (Al), showing largely varying (orders of magnitude) constants when modeled using first order kinetics. An effect of small primary sizes (<15 nm) was observed, leading to increased dissolution rate constants and solubility in some cases. However, the often extensive particle agglomeration can result in reduced nanospecific effects on dissolution and also an increased uncertainty related to the surface area, a parameter that largely influence the extent of dissolution. Promising ways to model surface areas of NPs in solution using fractal dimensions and size distributions are discussed in addition to nanospecific aspects related to other processes such as corrosion, adsorption of natural organic matter (NOM), presence of capping agents, and existence of surface defects. The importance of the experimental design on the results of dissolution experiments of metal and metal oxide NPs is moreover highlighted, including the influence of ionic metal solubility and choice of particle dispersion methodology.
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| 10. |
- Hedberg, Jonas, et al.
(författare)
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Interactions between surfactants and silver nanoparticles of varying charge
- 2012
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Ingår i: Journal of Colloid and Interface Science. - Amsterdam : Elsevier. - 0021-9797 .- 1095-7103. ; 369:1, s. 193-201
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Tidskriftsartikel (refereegranskat)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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