| 1. |
- Blomberg, Sara, et al.
(författare)
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Bimetallic nanoparticles as a model system for an industrial NiMo catalyst
- 2019
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Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 12:22
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Tidskriftsartikel (refereegranskat)abstract
- An in-depth understanding of the reactionmechanismis required for the further development of Mo-based catalysts for biobased feedstocks. However, fundamental studies of industrial catalysts are challenging, and simplified systems are often used without direct comparison to their industrial counterparts. Here, we report on size-selected bimetallic NiMo nanoparticles as a candidate for a model catalyst that is directly compared to the industrial system to evaluate their industrial relevance. Both the nanoparticles and industrial supported NiMo catalysts were characterized using surface- and bulk-sensitive techniques. We found that the active Ni and Mo metals in the industrial catalyst are well dispersed and well mixed on the support, and that the interaction between Ni and Mo promotes the reduction of the Mo oxide. We successfully produced 25 nm NiMo alloyed nanoparticles with a narrow size distribution. Characterization of the nanoparticles showed that they have a metallic core with a native oxide shell with a high potential for use as a model system for fundamental studies of hydrotreating catalysts for biobased feedstocks. © 2019 by the authors.
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| 2. |
- Eriksson, Mats, Professor, 1959-, et al.
(författare)
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Did the organization of primary care practices during the COVID-19 pandemic influence quality and safety? : an international survey
- 2024
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Ingår i: BMC Health Services Research. - : BioMed Central (BMC). - 1472-6963. ; 24
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Tidskriftsartikel (refereegranskat)abstract
- Background: Changes in demographics with an older population, the illness panorama with increasing prevalence of non-communicable diseases, and the shift from hospital care to home-based care place demand on primary health care, which requires multiprofessional collaboration and team-based organization of work. The COVID-19 pandemic affected health care in various ways, such as heightened infection control measures, changing work practices, and increased workload.Objectives: This study aimed to investigate the association between primary care practices’ organization, and quality and safety changes during the COVID-19 pandemic.Design: Data were collected from 38 countries in a large online survey, the PRICOV-19 study. For this paper, the participating practices were categorized as “Only GPs”, comprising practices with solely general practitioners (GPs) and/or GP trainees, without any other health care professionals (n = 1,544), and “Multiprofessional,” comprising practices with at least one GP or GP trainee and one or more other health professionals (n = 3,936).Results: Both categories of practices improved in infection control routines when compared before and during the COVID-19 pandemic. A larger proportion of the multiprofessional practices changed their routines to protect vulnerable patients. Telephone triage was used in more “Multiprofessional” practices, whereas “Only GPs” were more likely to perform video consultations as an alternative to physical visits. Both types of practices reported that the time to review new guidelines and scientific literature decreased during the pandemic. However, both had more meetings to discuss directives than before the pandemic.Conclusions: Multiprofessional teams were keener to introduce changes to the care organization to protect vulnerable patients. However, practices with only GPs were found to be more aligned with video consultations, perhaps reflecting the close patient-doctor relationship. In contrast, telephone triage was used more in multiprofessional teams.
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| 3. |
- 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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| 4. |
- 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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| 5. |
- Merte, Lindsay, et al.
(författare)
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Growth of Ultrathin Iron Oxide Films on Ag(100)
- 2015
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 119:5, s. 2572-2582
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Tidskriftsartikel (refereegranskat)abstract
- Ultrathin iron oxide films are useful model materials for fundamental studies of surface processes and exhibit intriguing properties as catalysts, as demonstrated recently in a number of studies utilizing platinum as a substrate. We report a study of the initial stages of iron oxide film growth on an Ag(100) surface using scanning tunneling microscopy, low energy electron diffraction, X-ray photoelectron spectroscopy, and near-edge X-ray absorption fine structure spectroscopy, with the goal of elucidating the effects of the substrate material on FeOx film growth and physical properties. We demonstrate that a well-ordered, monolayer-thick FeO(111) film can be prepared which is similar to the well-studied structure formed on Pt(111), though with a significantly expanded lattice constant indicative of smaller FeO buckling and weaker interactions with the substrate. Increased oxygen pressure during deposition leads to formation of a multilayer phase taking the form of well-ordered islands. Although superficially similar to FeO(111), spectroscopic measurements show a substantial proportion of Fe3+ in the phase. FeO(100) grains are observed upon deposition at elevated substrate temperatures, which is proposed to result from formation and oxidation of iron clusters embedded in the surface
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| 6. |
- Ajakaiye Jensen, Lucy Idowu, et al.
(författare)
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Effect of pd and ir as promoters in the activity of Ni/CeZrO2 catalyst for the reverse water-gas shift reaction
- 2021
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Ingår i: Catalysts. - : MDPI AG. - 2073-4344. ; 11:9
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Tidskriftsartikel (refereegranskat)abstract
- Catalytic conversion of CO2 to CO using reverse water gas shift (RWGS) reaction is a key intermediate step for many CO2 utilization processes. RWGS followed by well-known synthesis gas conversion may emerge as a potential approach to convert CO2 to valuable chemicals and fuels. Nickel (Ni) based catalysts with ceria-zirconia (Ce-Zr) support can be used to tune the metal-support interactions, resulting in a potentially enhanced CO2 hydrogenation rate and elongation of the catalyst lifespan. The thermodynamics of RWGS reaction is favored at high temperature for CO2 conversion. In this paper the effect of Palladium (Pd) and Iridium (Ir) as promoters in the activity of 10 wt%Ni 2 wt%Pd 0.1wt%Ir/CeZrO2 catalyst for the reverse water gas shift reaction was investigated. RWGS was studied for different feed (CO2:H2) ratios. The new active interface between Ni, Pd and Ir particles is proposed to be an important factor in enhancing catalytic activity. 10 wt%Ni 2 wt%Pd 0.1 wt%Ir/CeZrO2 catalyst showed a better activity with CO2 conversion of 52.4% and a CO selectivity of 98% for H2:CO2 (1:1) compared to the activity of 10%Ni/CeZrO2 with CO2 conversion of 49.9% and a CO selectivity of 93%. The catalytic activity for different feed ratios using 10 wt%Ni 2 wt%Pd 0.1 wt%Ir/CeZrO2 were also studied. The use of palladium and iridium boosts the stability and life span of the Ni-based catalysts. This indicates that the catalyst could be used potentially to design RWGS reactors for CO2 utilization units.
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| 7. |
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| 8. |
- Balmes, Olivier, et al.
(författare)
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Reversible formation of a PdCx phase in Pd nanoparticles upon CO and O-2 exposure
- 2012
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Ingår i: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9084 .- 1463-9076. ; 14:14, s. 4796-4801
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Tidskriftsartikel (refereegranskat)abstract
- The structure and chemical composition of Pd nanoparticles exposed to pure CO and mixtures of CO and O-2 at elevated temperatures have been studied in situ by a combination of X-ray Diffraction and X-ray Photoelectron Spectroscopy in pressures ranging from ultra high vacuum to 10 mbar and from room temperature to a few hundred degrees celsius. Our investigation shows that under CO exposure, above a certain temperature, carbon dissolves into the Pd particles forming a carbide phase. Upon exposure to CO and O-2 mixtures, the carbide phase forms and disappears reversibly, switching at the stoichiometric ratio for CO oxidation. This finding opens new scenarios for the understanding of catalytic oxidation of C-based molecules.
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| 9. |
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| 10. |
- Björsell, Tove, et al.
(författare)
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Risk factors for impaired respiratory function post COVID-19 : A prospective cohort study of nonhospitalized and hospitalized patients
- 2023
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Ingår i: Journal of Internal Medicine. - : Wiley-Blackwell Publishing Inc.. - 0954-6820 .- 1365-2796. ; 293:5, s. 600-614
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Severe COVID-19 increases the risk for long-term respiratory impairment, but data after mild COVID-19 are scarce. Our aims were to determine risk factors for reduced respiratory function 3-6 months after COVID-19 infection and to investigate if reduced respiratory function would relate to impairment of exercise performance and breathlessness.METHODS: Patients with COVID-19 were enrolled at the University Hospitals of Umeå and Örebro, and Karlstad Central Hospital, Sweden. Disease severity was defined as mild (nonhospitalized), moderate (hospitalized with or without oxygen treatment), and severe (intensive care). Spirometry, including diffusion capacity (DLCO ), was performed 3-6 months after hospital discharge or study enrollment (for nonhospitalized patients). Breathlessness (defined as ≥1 according to the modified Medical Research Council scale) and functional exercise capacity (1-min sit-to-stand test; 1-MSTST) were assessed.RESULTS: Between April 2020 and May 2021, 337 patients were enrolled in the study. Forced vital capacity and DLCO were significantly lower in patients with severe COVID-19. Among hospitalized patients, 20% had reduced DLCO , versus 4% in nonhospitalized. Breathlessness was found in 40.6% of the participants and was associated with impaired DLCO . A pathological desaturation or heart rate response was observed in 17% of participants during the 1-MSTST. However, this response was not associated with reduced DLCO .CONCLUSION: Reduced DLCO was the major respiratory impairment 3-6 months following COVID-19, with hospitalization as the most important risk factor. The lack of association between impaired DLCO and pathological physiological responses to exertion suggests that these physiological responses are not primarily related to decreased lung function.
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