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| 3. |
- Bergman, B, et al.
(författare)
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An intraindividual clinical comparison of 2 metal-ceramic systems.
- 1999
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Ingår i: International Journal of Prosthodontics. - 0893-2174 .- 1139-9791. ; 12:5, s. 444-7
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: It has been questioned whether the surface and color of the ceramic and the metal-ceramic bond strength of a titanium-ceramic system are comparable to those of a conventional noble alloy-ceramic system. It was therefore the aim of this study to carry out an intraindividual clinical comparison between crowns fabricated according to the Procera system (titanium copings veneered with a low-fusing ceramic) and noble-alloy copings veneered with a medium-fusing ceramic. MATERIALS AND METHODS: Twenty-one crown pairs were fabricated for eighteen patients; three of the patients were each provided with two crown pairs. After 2 years nineteen crown pairs in sixteen patients could be compared. Clinical examinations were performed by two calibrated dentists who are long experienced in prosthetic dentistry. The crowns were rated according to the California Dental Association system. In addition, Bleeding Index and Margin Index were evaluated. RESULTS: After 2 years the quality of surface and color of the ceramic material seemed to have deteriorated more in titanium-ceramic crowns than in conventional metal-ceramic crowns, although the difference was not statistically significant. Regarding anatomic form, margin integrity, Bleeding Index, and Margin Index the differences between the two crown systems were small. CONCLUSION: The low-fusing ceramics have been subject to improvements during the last few years. Their bond strength to titanium seems to be comparable to that of conventional metal-ceramic systems. However, in the long run one problem may be the surface and color stability of low-fusing ceramics. To make extended long-term comparisons between the two metal-ceramic systems possible the present patient material will be followed for a longer period than the current 2 years.
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- Bergman, Louise E., et al.
(författare)
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Comparing Depressive Symptoms, Emotional Exhaustion, and Sleep Disturbances in Self-Employed and Employed Workers : Application of Approximate Bayesian Measurement Invariance
- 2021
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Ingår i: Frontiers in Psychology. - : Frontiers Media SA. - 1664-1078. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Studies investigating differences in mental health problems between self-employed and employed workers have provided contradictory results. Many of the studies utilized scales validated for employed workers, without collecting validity evidence for making comparisons with self-employed. The aim of this study was (1) to collect validity evidence for three different scales assessing depressive symptoms, emotional exhaustion, and sleep disturbances for employed workers, and combinators; and (2) to test if these groups differed. We first conducted approximate measurement invariance analysis and found that all scales were invariant at the scalar level. Self-employed workers had least mental health problems and employed workers had most, but differences were small. Though we found the scales invariant, we do not find them optimal for comparison of means. To be more precise in describing differences between groups, we recommend using clinical cut-offs or scales developed with the specific purpose of assessing mental health problems at work.
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| 5. |
- Bergman, Susanna, et al.
(författare)
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In-situ studies of oxidation/reduction of copper in Cu-CHA SCR catalysts:comparison of fresh and SO2-poisoned catalysts
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- SO2-poisoning results in deactivation of Cu-CHA SCR under standard SCR conditions; however regeneration at 700 ◦C completely restores the SCR performance. To understand the nature of these effects, Cu-species in the fresh and poisoned catalystswere characterized by in-situ temperature-dependent time-resolved Cu K-edge X-ray absorption spectroscopy using the multivariate curve resolution alternating least squares (MCR-ALS) approach and continuous Cauchy wavelet transforms. The extracted chemically-meaningful reference spectra of Cu-species were analyzed by DFT-assisted XANES calculations. Cu-bisulfates werefound as the most energetically favorable poisoned Cu-species. The response of Cu-species to a reducing environment differs inthe fresh and SO2-poisoned catalysts. Differences in reducibility are related to the formation of quasi-linear Cu-complexes in the SO2-poisoned catalyst formed during heating in H2/He. Heating in H2/He leads to partial desulfurization of the poisoned catalyst. Cooling in H2/He after heating results in more facile formation of Cu-metal clusters in fresh catalyst than in SO2-poisoned.
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| 6. |
- Bergman, Susanna L., et al.
(författare)
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In-situ studies of oxidation/reduction of copper in Cu-CHA SCR catalysts: Comparison of fresh and SO2-poisoned catalysts
- 2020
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Ingår i: Applied Catalysis B: Environmental. - : Elsevier BV. - 0926-3373 .- 1873-3883. ; 269
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Tidskriftsartikel (refereegranskat)abstract
- SO2-poisoning results in deactivation of Cu-CHA SCR under standard SCR conditions; however regeneration at 700 °C completely restores the SCR performance. To understand the nature of these effects, Cu-species in the fresh and poisoned catalysts were characterized by in-situ temperature-dependent time-resolved Cu K-edge X-ray absorption spectroscopy using the multivariate curve resolution alternating least squares (MCR-ALS) approach and continuous Cauchy wavelet transforms. The extracted chemically-meaningful reference spectra of Cu-species were analyzed by DFT-assisted XANES calculations. Cu-bisulfates were found as the most energetically favorable poisoned Cu-species. The response of Cu-species to a reducing environment differs in the fresh and SO2-poisoned catalysts. Differences in reducibility are related to the formation of quasi-linear Cu-complexes in the SO2-poisoned catalyst formed during heating in H2/He. Heating in H2/He leads to partial desulfurization of the poisoned catalyst. Cooling in H2/He after heating results in more facile formation of Cu-metal clusters in fresh catalyst than in SO2-poisoned.
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| 7. |
- Bernhard-Oettel, Claudia, et al.
(författare)
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Flourish, fight or flight : Health and well-being in self-employment over time - associations with business success
- 2019
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Ingår i: Abstract Book of the 19th European Association of Work and Organizational Psychology Congress. ; , s. 207-207
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Purpose: Around 9% of the working population in Sweden consists of self-employed business owners, but a considerable amount of them struggle to consolidate or expand their businesses. Among the factors predicting business success the decisive role of long-term health of business owners has been acknowledged only recently, but longitudinal studies testing this assumption are scarce. Based on the conservation of resources theory, good health can be seen as a resource that helps business owners to tackle high workloads and make business succeed.Design: Data from the Swedish Longitudinal Occupational Health Survey is used. Starting in 2012, N=554 self-employed have answered three or more times in the biannual data collection. Latent growth curve modelling is employed to study general and mental health trajectories and their associations with business survival over time.Results: Preliminary descriptive analyses on biannual changes suggest that roughly one in ten self-employed leaves self-employment at follow-up. Job demands and emotional exhaustion are higher among those who leave compared to those who remain in business. After integrating new data collected in 2018, growth curve analyses are run over the whole longitudinal sample, and associations of health trajectories to business survival will be tested.Limitations: Data is collected with questionnaires, and business success is operationalized as business survival only.Research/Practical Implications: Study results increase knowledge on the self-employed’s health developments, vulnerable groups with poor health and risk of business failure can be detected.Originality/Value: This is one of few studies on longitudinal developments of health in selfemployed business owners.
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| 8. |
- Bernhard-Oettel, Claudia, et al.
(författare)
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Flourish, fight or flight : health in self-employment over time-associations with individual and business resources
- 2024
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Ingår i: International Archives of Occupational and Environmental Health. - 0340-0131 .- 1432-1246. ; 97, s. 263-278
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Using COR theory to study developments of health and other key resources in self-employed workers in Sweden over 6 years, this study: (1) explored whether the heterogenous group of self-employed workers contained subgroups with different health trajectories, (2) investigated whether these were more typical for certain individuals (with respect to age, gender, sector, education, employment status), and (3) compared the different health trajectories regarding resource development in mental well-being, business resources, employment status, work ability. Method: The study used data from the Swedish longitudinal occupational survey of health (SLOSH) and included participants working as self-employed or combiner (N = 2642). Result: Five trajectories were identified with latent class growth curve model analysis (LCGM). Two health trajectories with (1) very good, respective (2) good stable health (together comprising 78.5% of the participants), (3) one with moderate stable health (14.8%), (4) one with a U-shaped form (1.9%), and (5) one with low, slightly increasing health (4.7%). The first two trajectories flourish: they maintained or increased in all key resources and were more likely to remain self-employed. Trajectories three and five consist of those who fight to maintain or increase their resources. Workers in the U-shaped health trajectory show signs of fight and flight after loss in health and other key resources. Conclusions: Studying subgroups with different resource developments over time was suitable to understand heterogeneity in self-employed workers. It also helped to identify vulnerable groups that may benefit from interventions to preserve their resources.
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| 9. |
- Bernhard-Oettel, Claudia, et al.
(författare)
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Flourish, fight or flight: Health and well-being in self-employment over time-associations with business success
- 2019
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Konferensbidrag (refereegranskat)abstract
- Purpose: Around 9% of the working population in Sweden consists of self-employed business owners, but a considerable amount of them struggle to consolidate or expand their businesses. Among the factors predicting business success the decisive role of long-term health of business owners has been acknowledged only recently, but longitudinal studies testing this assumption are scarce. Based on the conservation of resources theory, good health can be seen as a resource that helps business owners to tackle high workloads and make business succeed.Design: Data from the Swedish Longitudinal Occupational Health Survey is used. Starting in 2012, N= 554 self-employed have answered three or more times in the biannual data collection. Latent growth curve modelling is employed to study general and mental health trajectories and their associations with business survival over time.Results: Preliminary descriptive analyses on biannual changes suggest that roughly one in ten self-employed leaves self-employment at follow-up. Job demands and emotional exhaustion are higher among those who leave compared to those who remain in business. After integrating new data collected in 2018, growth curve analyses are run over the whole longitudinal sample, and associations of health trajectories to business survival will be tested.Limitations: Data is collected with questionnaires, and business success is operationalized as business survival only.
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| 10. |
- Dahlin, Sandra, et al.
(författare)
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Multivariate analysis of the effect of biodiesel-derived contaminants on V2O5-WO3/TiO2 SCR catalysts
- 2016
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Ingår i: Applied Catalysis B. - : Elsevier. - 0926-3373 .- 1873-3883. ; 183, s. 377-385
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates the effect of biodiesel-derived contaminants on vanadia-based NH3-SCR catalysts in heavy-duty exhaust aftertreatment. The aim was to study, not only the effect of single contaminants on the catalyst performance, but also of possible interaction effects between poisons.The effect of six potential catalyst poisons (Na, K, Mg, P, S and Zn) was evaluated using an experimental design and multivariate data analysis. Monolithic V2O5-WO3/TiO2 catalysts were subjected to accelerated laboratory-scale aging, where the six contaminants were fed simultaneously using a wet impregnation method. In addition to NOx conversion tests, the catalysts were characterized by means of ICP-OES, SEM-EDX, XPS, N2 physisorption and NH3-TPD. The lab-aged samples were compared to fresh and vehicle-aged catalysts.The accelerated aging method showed good reproducibility and gave rise to surface compounds similar to those found in vehicle-aged catalysts. Despite plausible differences regarding penetration depth of the contaminants into the walls of the catalyst, the aging method appears to be an efficient way to point out significant chemical poisons.The model obtained from the experimental design was found to correlate well with the experimental data and can therefore be used to predict effects of the various poisons and poison interactions. Significant effects on the NO. x conversion were found for P, S, Na, Mg and K as well as for the interactions P. ×. Na, P. ×. K and S. ×. Na. A poisoning effect was found for Mg, Na, K, P. ×. K, and P. ×. Na, where Na and K exhibited the strongest poisoning effect. The deactivating effect of alkali was lowered in the presence of phosphorus and sulfur, which is explained by the formation of phosphates and sulfates, preventing the interaction of the alkali metals with the vanadia active sites.
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