| 1. |
- Faisal, Abrar, et al.
(author)
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Recovery of l-Arginine from Model Solutions and Fermentation Broth Using Zeolite-Y Adsorbent
- 2019
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In: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 7:9, s. 8900-8907
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Journal article (peer-reviewed)abstract
- Arginine was produced via fermentation of sugars using the engineered microorganism Escherichia coli. Zeolite-Y adsorbents in the form of powder and extrudates were used to recover arginine from both a real fermentation broth and aqueous model solutions. An adsorption isotherm was determined using model solutions and zeolite-Y powder. The saturation loading was determined to be 0.2 g/g using the Sips model. Arginine adsorbed from a real fermentation broth using either zeolite-Y powder or extrudates both showed a maximum loading of 0.15 g/g at pH 11. This adsorbed loading is very close to the corresponding value obtained from the model solution showing that under the experimental conditions the presence of additional components in the broth did not have a significant effect on the adsorption of arginine. Furthermore, a breakthrough curve was determined for extrudates using a 1 wt % arginine model solution. The selectivity for arginine over ammonia and alanine from the real fermentation broth at pH 11 was 1.9 and 8.3, respectively, for powder, and 1.0, and 4.1, respectively, for extrudates. To the best of our knowledge, this is the first time recovery of arginine from real fermentation broths using any type of adsorbent has been reported.
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| 2. |
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| 3. |
- Asplund, Sofia, et al.
(author)
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Organizational and psychosocial environmental work factors associated with self-rated exhaustion disorder among municipal employees in rural northern Sweden
- 2023
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In: Work. - : IOS Press. - 1051-9815 .- 1875-9270. ; 75:4, s. 1215-1229
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Journal article (peer-reviewed)abstract
- Background: Research indicates that good organizational and psychosocial environments are vital to well-functioning workplaces and employee health. Working in the municipal sector and in the rural context may contribute to more health problems, poorer organizational and psychosocial work environments, and higher sick-leave rates.Objective: The aim of this study was to explore organizational and psychosocial environmental work factors among municipal employees with or without self-rated exhaustion disorder (s-ED) in rural northern Sweden.Methods: The Modern Work Life Questionnaire and the Self-Rated Exhaustion Disorder Scale were used among 1093 municipal employees.Results: The results showed that there were significant differences between the s-ED and the non-s-ED group in all but one of the organizational and psychosocial environmental work factors. Various demands, i.e. quantitative, emotional, intellectual, and IT demands were some factors associated with the s-ED group. Social support, resources, and time for work and reflection were some factors associated with the non-s-ED group. Both the s-ED and the non-s-ED groups assessed significantly higher emotional demands and less resources compared to national reference values.Conclusion: Findings from this study are relevant to a better understanding what organizational and psychosocial work environmental work factor the employer need to pay extra attention to. Addressing risk and protective factors in the work environment could tribute to promote occupational well-being, preventing exhaustion disorder and long-term sick leave among municipal employees in rural northern Sweden.
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| 4. |
- Asplund, Sofia, et al.
(author)
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Self-rated exhaustion disorder and associated health-related factors among municipal employees in rural areas of northern Sweden
- 2021
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In: International Archives of Occupational and Environmental Health. - : Springer. - 0340-0131 .- 1432-1246. ; , s. 659-668
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Journal article (peer-reviewed)abstract
- OBJECTIVE: The aims of this study among municipal employees in rural areas of northern Sweden were to assess the prevalence of self-rated exhaustion disorder (s-ED), describe plausible between-group differences in self-reported health-related factors among employees with or without s-ED, and identify health-related factors associated with s-ED.METHODS: In a cross-sectional study, data were collected from 1093 municipal employees (76.1% women) in two rural areas using an instrument measuring s-ED and health variables drawn from the Modern Worklife Questionnaire (MWQ), the Perceived Stress Scale (PSS), and the National Board of Health and Welfare's questions about physical activity. Comparisons were made between an s-ED and a non-s-ED group. Health-related factors associated with s-ED were identified through a logistic regression.RESULTS: Self-rated exhaustion disorder was reported by 21.5% of the participants. Health-related factors associated with s-ED were cognitive problems, sleep problems, depressive symptoms, high stress, poor self-rated health, and stomach problems. There was no statistically significant difference in the prevalence of participants who met the criteria of physical activity among s-ED and non-s-ED group.CONCLUSION: Findings from this study suggest that s-ED is more common among municipal employees in rural areas than in other working populations in Sweden. Several health-related factors were associated with s-ED. Regular use of a self-rated instrument in evaluating the organizational and social work environment can identify people at risk of developing exhaustion disorder and requiring long-term sick leave.
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| 5. |
- Asplund, Sofia, 1982-
(author)
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Work-related stress among municipal employees in rural northern Sweden
- 2022
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Doctoral thesis (other academic/artistic)abstract
- Background: Many rural municipalities in Sweden are facing challenges like depopulation, decreased economy, and difficulties in recruiting staff. Living and working in rural areas may involve adverse working conditions and higher risks of ill-health. Work is generally good for employee health, but various physical and psychosocial aspects of work can also be hazards and cause work-related stress, health problems, reduced productivity, and long-term sick leave. Leadership by managers in the organisation is important for the work environment, work performance, and occupational health of employees. The Swedish municipal sector employs almost 20% of employees in the labour market, where school, preschool and care of older people are the dominating areas. Previous research has shown that there are adverse psychosocial working conditions in Swedish municipal organisations. The municipal sector has the highest rate of long-term sick leave compared to other sectors in the labour market, mainly due to stress-related disorders, such as exhaustion disorder (ED). Therefore, it is important to focus on organisational and psychosocial work environments, work-related stress, and health in the municipal sector of rural northern Sweden.Aim: The overall aim was to explore organisational and psychosocial work environments, work-related stress, and health among municipal employees in rural northern Sweden.Methods: Both quantitative and qualitative methods were used to collect data. Study I and II had a quantitative approach, a cross-sectional design, and used a questionnaire for collecting data. Participants were employees (n =1093) in the municipal sector in two municipalities in rural northern Sweden. The questionnaire was constructed to contain instruments measuring the organisational and psychosocial work environments, perceived stress, self-rated exhaustion disorder (s-ED), and physical activity. Quantitative data were analysed using logistic regression in Study I, and partial least squares regression in Study II. Studies III and IV had a qualitative approach. In Study III, semi-structured individual interviews were conducted with 15 municipal employees with high self-reported stress. In Study IV, semi-structured individual interviews were conducted with 15 managers at different levels in the municipal sector. All qualitative data were analysed using inductive qualitative content analysis.Results: In Study I, results showed that 21.5 % of the municipal employees reported s-ED.Cognitive problems, sleep problems,depressiveivsymptoms, high stress, poor self-rated health, and stomach problems were the health-related factors most strongly associated with s-ED. In Study II, results showed that there were significant differences between the s-ED and the non–s-ED group in all but one of the 32 organisational and psychosocial environmental work factors. Various demands—i.e., quantitative, emotional, intellectual—and work conflicts were important factors associated with s-ED. Social support, resources, and time for work and reflection were important factors associated with non–s-ED. Findings from Study III showed that the employees with high self-reported stress experienced feelings of suffering through endless chaos when they worked in an organisation with high demands and low resources, control, and support. They also experienced feelings of insufficiency, and negative effects on health and family life. Findings from Study IV showed that managers in the municipal sector experienced feelings of striving for stability on shaky ground. They struggled inside slimmed-down organisations with a substitute shortage and reduced means, were burdened by conflicting demands, and experienced health and family life impairments. Managers expressed the importance of motivation, social support, and coping strategies.Conclusion: This thesis illuminates adverse psychosocial working conditions among municipal employees in two municipalities in the rural context of northern Sweden, where a stressful work environment, s-ED and health impairments are relatively common.It also provides important insights of municipal employee’s experiences of work-related stress, the importance of acknowledging suffering, and managers’ experiences of working in municipal organisations with shrinking resources, as in addition to a work–family imbalance. It seems important that organisations in the municipal sector have supportive and effective leadership, and allow employees control over their work. Furthermore, it seems important that various demands are balanced by sufficient resources; such as staff, social support, and economic resources in order to prevent work-related stress. Findings from this thesis can contribute to future interventions, aiming to prevent work-related stress and improve occupational well-being and work performance. They also have value for development work in municipal organisations.
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| 6. |
- Berglin, Mattias, 1970, et al.
(author)
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Use of surface-sensitive methods for the study of adsorption and cross-linking of marine bioadhesives
- 2005
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In: Journal of Adhesion. - : Informa UK Limited. - 0021-8464 .- 1563-518X .- 1545-5823. ; 81:7-8, s. 805-822
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Journal article (peer-reviewed)abstract
- The establishment of the bond of sessile marine organisms such as barnacles, mussels, and algae in the marine environment starts with the secretion and the adsorption of the adhesive biopolymers to the substrate. Subsequently, this is followed by the formation of cohesive interactions with the next layer of adhesive biopolymers that are deposited/adsorbed on top of the first layer. These two fundamental processes for the adhesive plaque buildup have been subjected to several investigations in recent years using model molecules, especially Mefp-1 extracted from the blue mussel Mytilus edulis. With the introduction of optical surface-sensitive methods such as ellipsometry, surface plasmon resonance (SPR), and infrared spectroscopy (IR), it has been possible to elucidate both the kinetics of adsorption and structure of the Mefp-1 film. In contrast to adsorption, the cohesive interactions or the cross-linking are not easily followed with these optical methods and new approaches and techniques are required. One such technique that has been useful is the quartz-crystal microbalance with dissipation monitoring (QCM-D), which has been used for cross-linking studies of a variety of biopolymers including bioadhesives from mussel and algae. Copyright © Taylor & Francis Inc.
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| 7. |
- Bäcklund, Ylva, et al.
(author)
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Wet etching of single crystal quartz
- 1998
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In: Workshop of Physical Chemistry of Wet Chemical Etching of Silicon, May 17-19, Holten, The Netherlands.
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Conference paper (peer-reviewed)
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| 8. |
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| 9. |
- Carabante, Ivan, et al.
(author)
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Adsorption of As (V) on iron oxide nanoparticle films studied by in situ ATR-FTIR spectroscopy
- 2009
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In: Colloids and Surfaces A. - : Elsevier BV. - 0927-7757 .- 1873-4359. ; 346:1-3, s. 106-113
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Journal article (peer-reviewed)abstract
- Stabilization of arsenic contaminated soils by iron oxides has been proposed as a remediation technique to prevent leaching of arsenate into the environment. Fundamental studies are needed to establish under which conditions the complexes formed are stable. In the present work, a powerful technique, viz. ATR-FTIR spectroscopy, is adapted to studies of adsorption of arsenate species on iron oxides. This technique facilitates acquisition of both quantitative and qualitative in situ adsorption data.In the present work, about 800 nm thick films of 6-lineferrihydrite were deposited on ZnSe ATR crystals. Arsenate adsorption on the ferrihydrite film was studied at pD values ranging from 4 to 12 and at an arsenate concentration of 0.03 mM in D2O solution. The amount of adsorbed arsenate decreased with increasing pD as a result of the more negatively charged iron oxide surface at higher pD values. The adsorption and desorption kinetics were also studied. Arsenate showed a higher adsorption rate within the first 70 minutes and a much lower adsorption rate from 70 up to 300 minutes. The low adsorption rate at longer reaction times was partly due to a low desorption rate of already adsorbed carbonate species adsorbed at the surface. The desorption of carbonate species was evidenced by the appearance of negative absorption bands. The desorption of adsorbed arsenate complexes was examined by flushing with D2O at pD 4 and 8.5 and it was found that the complexes were very stable at pD 4 suggesting formation of mostly inner-sphere complexes whereas a fraction of the complexes at pD 8.5 were less stable than at pD 4, possibly due to the formation of outer-sphere complexes.In summary, the ATR technique was shown to provide in situ information about the adsorption rate, desorption rate and the speciation of the complexes formed within a single experiment, which is very difficult to obtain using other techniques.
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| 10. |
- Carabante, Ivan, et al.
(author)
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In situ ATR-FTIR studies on the competitive adsorption of arsenate and phosphate on ferrihydrite
- 2010
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In: Journal of Colloid and Interface Science. - : Elsevier BV. - 0021-9797 .- 1095-7103. ; 351:2, s. 523-531
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Journal article (peer-reviewed)abstract
- In the present study, in-situ ATR-FTIR spectroscopy was used for the first time to study the competitive adsorption of phosphate and arsenate on ferrihydrite. Deuterium oxide was used as solvent to facilitate the interpretations of recorded infrared spectra.It was found that arsenate and phosphate adsorbed more strongly at lower pD values, showing similarities in the adsorption behavior as a function of pD. However, arsenate complexes were found to be more strongly adsorbed than phosphate complexes in the pD range studied. About five times higher concentration of phosphate in solution was needed to reduce the absorbance due to pre-adsorbed arsenate to the same relative level as for pre-adsorbed phosphate, which was desorbed using a solution containing equal (molar) concentrations in arsenate and phosphate. At pD 4, two phosphate complexes were adsorbed on the iron oxide, one deuterated and one de-deuterated. When phosphate was pre-adsorbed and arsenate subsequently added to the system, the deuterated phosphate complex desorbed rapidly while the de-deuterated phosphate complex was quite stable. At pD 8.5, only the de-deuterated phosphate complex was adsorbed on the iron oxide. Moreover, the arsenate adsorbed was also predominantly de-deuterated as opposite to the arsenate adsorbed at pD 4. During the substitution experiments the configuration of these complexes on the iron oxide surface did not change. To the best of our knowledge, this is the first time this difference in stability of the different phosphate complexes is reported and shows the power of employing in-situ spectroscopy for this kind of studies.
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| 11. |
- Carabante, Ivan, et al.
(author)
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Influence of Zn(II) on the adsorption of arsenate onto ferrihydrite
- 2012
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In: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 46:24, s. 13152-13159
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Journal article (peer-reviewed)abstract
- Addition of iron oxide to arsenic-contaminated soil has been proposed as a means of reducing the mobility of arsenic in the soil. Arsenic and zinc are common coexisting contaminants in soils. The presence of zinc therefore may affect the adsorption properties of arsenic on iron oxide, and may thus affect its mobility in the soil. The influence of Zn(II) on the adsorption of arsenate ions on iron oxide was studied. Batch adsorption experiments indicated that Zn(II) increased the arsenate removal from a solution by ferrihydrite at pH 8. However, ATR-FTIR spectroscopy showed that no adsorption of arsenate on a ferrihydrite film occurred at pD 8 in the presence of Zn(II). Precipitation of zinc hydroxide carbonate followed by arsenate adorption onto the precipitate was found to be a plausible mechanism explaining the arsenate removal from a solution in the presence of Zn(II) at pH/pD 8. The previously suggested mechanisms attributing the enhanced removal of arsenate from solution in the presence of Zn(II) to additional adsorption on iron oxides could not be verified under the experimental conditions studied. It was also shown that at pH/pD 4, the presence of Zn(II) in the system did not significantly affect the adsorption of arsenate on ferrihydrite.
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| 12. |
- Carabante, Ivan, et al.
(author)
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Reutilization of porous sintered hematite bodies as effective adsorbents for arsenic(V) removal from water
- 2014
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In: Industrial & Engineering Chemistry Research. - : American Chemical Society (ACS). - 0888-5885 .- 1520-5045. ; 53:32, s. 12689-12696
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Journal article (peer-reviewed)abstract
- A method was developed to enhance the arsenic adsorption capacity of porous bodies of sintered hematite. The method comprised the formation of a coating of 1 wt % iron oxide nanoparticles on the raw material. The nanoparticles showed two distinct habits: spherical habit, likely ferrihydrite, and acicular habit, likely goethite and/or akaganéite. The specific surface area of the hematite raw material increased from 0.5 to 3.75 m2/g, and the adsorption capacity increased from negligible to 0.65 mg of [As]/g as calculated from equilibrium and breakthrough adsorption data. Equilibrium adsorption data of arsenate on the adsorbent from a solution at pH 5 followed the Langmuir model, while breakthrough adsorption data for a 500 μg/L arsenate solution at pH 5 followed the Thomas model. The adsorbed arsenic could be desorbed using distilled water at pH 12. These results show the potential for the reutilization of waste products comprising coarse hematite bodies as adsorbents.
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| 13. |
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| 14. |
- Carvalho, Lara, et al.
(author)
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Alkali enhanced biomass gasification with in situ S capture and a novel syngas cleaning : Part 2: Techno-economic analysis
- 2018
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In: Energy. - : Elsevier. - 0360-5442 .- 1873-6785. ; 165:Part B, s. 471-482
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Journal article (peer-reviewed)abstract
- Previous research has shown that alkali addition has operational advantages in entrained flow biomass gasification and allows for capture of up to 90% of the biomass sulfur in the slag phase. The resultant low-sulfur content syngas can create new possibilities for syngas cleaning processes. The aim was to assess the techno-economic performance of biofuel production via gasification of alkali impregnated biomass using a novel gas cleaning systemcomprised of (i) entrained flow catalytic gasification with in situ sulfur removal, (ii) further sulfur removal using a zinc bed, (iii) tar removal using a carbon filter, and (iv) CO2 reductionwith zeolite membranes, in comparison to the expensive acid gas removal system (Rectisol technology). The results show that alkali impregnation increases methanol productionallowing for selling prices similar to biofuel production from non-impregnated biomass. It was concluded that the methanol production using the novel cleaning system is comparable to the Rectisol technology in terms of energy efficiency, while showing an economic advantagederived from a methanol selling price reduction of 2–6 €/MWh. The results showed a high level of robustness to changes related to prices and operation. Methanol selling prices could be further reduced by choosing low sulfur content feedstocks.
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| 15. |
- De Brandt, Jana, 1991-, et al.
(author)
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The Borg Cycle Strength Test (BCST) for prescribing supramaximal high-intensity interval training (HIIT) in COPD
- 2023
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In: European Respiratory Journal. - : European Respiratory Society. - 0903-1936 .- 1399-3003. ; 62:Supplement 67
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Journal article (other academic/artistic)abstract
- Background: Prescription of supramaximal HIIT is ideally based on an all-out test. This is, however, not suitable for people with COPD, leading to the use of workloads obtained during a maximal incremental test (CPET), which are less specific for the prescription of supramaximal HIIT. Hence, we evaluated the feasibility of a submaximal anaerobic test, the BCST, that has been used in older adults to prescribe supramaximal HIIT, and the anaerobic cycle capacity of people with COPD vs. matched healthy controls (HC).Methods: Sixteen persons with COPD and HC performed a CPET and a BCST. The BCST is an incremental stepwise test (30s cycling, 30s rest) with two end-of-test criteria: 1) Rating of perceived exertion (RPE) ≥17 or 2) cadence <75 RPM for >5s. End-of-test RPE, symptoms, peak workload (Wpeak) and cardiorespiratory demand were obtained to assess feasibility.Results: A higher Wpeak and lower RPE, symptoms and cardiorespiratory demand were observed in the BCST vs. CPET in both groups (Table1). Absolute BCST Wpeak was significantly lower, while relative BCST Wpeak (%Wpeak CPET) was similar in people with COPD (146±24%) vs. HC (157±17%)(P=0.114).Conclusion: In people with COPD, the BCST is a feasible short-duration submaximal anaerobic test specific for prescribing supramaximal HIIT. Compared to the CPET, it allows for higher workloads with lower cardiorespiratory demand and symptom burden.
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| 16. |
- Faisal, Abrar, et al.
(author)
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MFI zeolite as adsorbent for selective recovery of hydrocarbons from ABE fermentation broths
- 2014
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In: Adsorption. - : Springer Science and Business Media LLC. - 0929-5607 .- 1572-8757. ; 20:2-3, s. 465-470
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Journal article (peer-reviewed)abstract
- 1-Butanol and butyric acid are two interesting compounds that may be produced by acetone, butanol, and ethanol fermentation using e.g. Clostridium acetobutylicum. The main drawback, restricting the commercialization potential of this process, is the toxicity of butanol for the cell culture resulting in low concentrations of this compound in the broth. To make this process economically viable, an efficient recovery process has to be developed. In this work, a hydrophobic MFI type zeolite with high silica to alumina ratio was evaluated as adsorbent for the recovery of butanol and butyric acid from model solutions. Dual component adsorption experiments revealed that both butanol and butyric acid showed a high affinity for the hydrophobic MFI zeolite when adsorbed from aqueous model solutions. Multicomponent adsorption experiments using model solutions, mimicking real fermentation broths, revealed that the adsorbent was very selective to the target compounds. Further, the adsorption of butyric and acetic acid was found to be pH dependent with high adsorption below, and low adsorption above, the respective pKa values of the acids. Thermal desorption of butanol from MFI type zeolite was also studied and a suitable desorption temperature was identified.
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| 17. |
- Faisal, Abrar, et al.
(author)
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Recovery of butanol from model ABE fermentation broths using MFI adsorbent: a comparison between traditional beads and a structured adsorbent in the form of a film
- 2016
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In: Adsorption. - : Springer Science and Business Media LLC. - 0929-5607 .- 1572-8757. ; 22:2, s. 205-214
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Journal article (peer-reviewed)abstract
- Butanol, a promising biofuel, can be produced by ABE (acetone, butanol and ethanol) fermentation using e.g. Clostridium acetobutylicum. However, the butanol concentration in the resulting broth is limited to only ca. 20 g/L due to the toxicity for the microorganisms. This low product concentration demands an efficient recovery process for successful commercialization of this process. In this study, a structured adsorbent in the form of steel monolith coated with a silicalite-1 film was prepared using the in situ growth method. The adsorbent was carefully characterized by SEM and XRD. The performance of the adsorbent was evaluated by performing breakthrough experiments at room temperature using model ABE fermentation broths and the performance was compared with that of traditional adsorbents in the form of beads. The structured silicalite-1 adsorbent showed less saturation loading time as compared to commercial binder free silicalite-1 beads, reflecting the different dimensions of the columns used, set by experimental constraints. Studies of the desorption process showed that by operating at appropriate conditions, butanol with high concentration i.e. up to 95.2 wt% for butanol–water model system and 88.5 wt% for ABE fermentation broth can be obtained using the structured silicalite-1 adsorbent. Commercial silicalite-1 beads also showed good selectivity but the concentration of butanol in the desorbed product was limited to 70 % for the butanol–water model system and 69 % for ABE fermentation broth, probably as a result of entrained liquid between the beads.
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| 18. |
- Faisal, Abrar, et al.
(author)
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Zeolite MFI adsorbent for recovery of butanol from ABE fermentation broths produced from an inexpensive black liquor-derived hydrolyzate
- 2018
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In: Biomass Conversion and Biorefinery. - : Springer. - 2190-6815 .- 2190-6823. ; 8:3, s. 679-687
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Journal article (peer-reviewed)abstract
- In this work, high-silica MFI zeolite adsorbent was evaluated for selective recovery of butanol from a real ABE (acetone, butanol, and ethanol) fermentation broth by batch adsorption measurements. The fermentation broth was produced using a hydrolyzate originating from Kraft black liquor, an internal stream in pulp mills, i.e., a low-cost substrate. The adsorbent was very selective towards butanol and butyric acid and became nearly saturated with a mixture of butanol and butyric acid with relative amounts of butanol and butyric acid depending on the pH. The presence of phenolic compounds in significant amounts in the fermentation broths, originating from the black liquor hydrolyzate, did not affect the adsorption of butanol and butyric acid.
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| 19. |
- Fant, Camilla, et al.
(author)
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Investigation of Adsorption and Cross-Linking of a Mussel Adhesive Protein Using Attenuated Total Internal Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR)
- 2010
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In: Journal of Adhesion. - : Informa UK Limited. - 0021-8464 .- 1545-5823 .- 1563-518X. ; 86:1, s. 25-38
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Journal article (peer-reviewed)abstract
- Mytilus edulis foot protein 1 (Mefp-1) contains the redox-functional amino acid 3,4-dihydroxyphenylalanine (DOPA), which is a typical feature of most mefp proteins. We have previously shown, using combined optic (ellipsometry) and acoustic (QCM-D) measurements, that the oxidizing agent sodium periodate (NaIO4) and the transition metal ion Cu2+ promote cross-linking of Mefp-1. However, different chemical reaction mechanisms can not be distinguished using these methods. In the present study, we have complemented our previous investigations using Attenuated Total Internal Reflection Fourier Transform Infrared spectroscopy (ATR-FTIR), allowing a spectroscopic analysis of NaIO4 and Cu2+-induced cross-linking of Mefp-1 adsorbed on a ZnSe surface. In aqueous solution, adsorbed Mefp-1 displays absorption bands at 1570, 1472, 1260, and 973 cm(-1). Upon addition of NaIO4 and Cu2+, the absorptions at 1570, 1472, and 973 cm(-1) increase by approximately a factor of two. In contrast, the band at 1260 cm(-1) disappears upon cross-linking using NaIO4, but remains unchanged upon addition of Cu2+. This demonstrates that the band at 1260cm(-1) is attributed to the C O stretching vibration of the side chain hydroxyl groups in DOPA and that Cu2+ forms complexes with DOPA rather than transform it into an o-quinone. Moreover, upon addition of NaIO4 after cross-linking using Cu2+, the band at 1260cm(-1) disappears, indicating that the complex formation between DOPA and Cu2+ is reversed when DOPA is transformed into the o-quinone. These results demonstrate that NaIO4, which initiates a similar reaction to the naturally occurring enzyme catechol oxidase, contributes to the formation of di-DOPA cross-links. In contrast, the dominating contribution to the cross-linking from Cu2+, which is accumulated at high concentrations in the byssus thread of the blue mussel, is via complex formation between the metal and DOPA residues.
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| 20. |
- Farzaneh, Amirfarrokh, et al.
(author)
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Adsorption of Butanol and Water Vapors in Silicalite‑1 Films with a Low Defect Density
- 2016
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In: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 32, s. 11789-11798
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Journal article (peer-reviewed)abstract
- Pure silica zeolites are potentially hydrophobic and have therefore been considered to be interesting candidates for separating alcohols, e.g., 1-butanol, from water. Zeolites are traditionally synthesized at high pH, leading to the formation of intracrystalline defects in the form of silanol defects in the framework. These silanol groups introduce polar adsorption sites into the framework, potentially reducing the adsorption selectivity toward alcohols in alcohol/water mixtures. In contrast, zeolites prepared at neutral pH using the fluoride route contain significantly fewer defects. Such crystals should show a much higher butanol/water selectivity than crystals prepared in traditional hydroxide (OH−) media. Moreover, silanol groups are present at the external surface of the zeolite crystals; therefore, minimizing the external surface of the studied adsorbent is important. In this work, we determine adsorption isotherms of 1-butanol and water in silicalite-1 films prepared in a fluoride (F−) medium using in situ attenuated total reflectance−Fourier transform infrared (ATR−FTIR) spectroscopy. This film was composed of well intergrown, plate-shaped b-oriented crystals, resulting in a low external area. Single-component adsorption isotherms of 1-butanol and water were determined in the temperature range of 35− 80 °C. The 1-butanol isotherms were typical for an adsorbate showing a high affinity for a microporous material and a large increase in the amount adsorbed at low partial pressures of 1-butanol. The Langmuir−Freundlich model was successfully fitted to the 1-butanol isotherms, and the heat of adsorption was determined. Water showed a very low affinity for the adsorbent, and the amounts adsorbed were very similar to previous reports for large silicalite-1 crystals prepared in a fluoride medium. The sample also adsorbed much less water than did a reference silicalite-1(OH−) film containing a high density of internal defects.The results show that silicalite-1 films prepared in a F− medium with a low density of defects and external area are very promising for the selective recovery of 1-butanol from aqueous solutions.
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| 21. |
- Farzaneh, Amirfarrokh, et al.
(author)
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Adsorption of Water and Butanol in Silicalite-1 Film Studied with in-situ ATR-FTIR Spectroscopy
- 2015
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In: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 31:17, s. 4887-4894
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Journal article (peer-reviewed)abstract
- Biobutanol produced by, e.g., acetone–butanol–ethanol (ABE) fermentation is a promising alternative to petroleum-based chemicals as, e.g., solvent and fuel. Recovery of butanol from dilute fermentation broths by hydrophobic membranes and adsorbents has been identified as a promising route. In this work, the adsorption of water and butanol vapor in a silicalite-1 film was studied using in situ attenuated total reflectance–Fourier transform infrared (ATR–FTIR) spectroscopy to better understand the adsorption properties of silicalite-1 membranes and adsorbents. Single-component adsorption isotherms were determined in the temperature range of 35–120 °C, and the Langmuir model was successfully fitted to the experimental data. The adsorption of butanol is very favorable compared to that of water. When the silicalite-1 film was exposed to a butanol/water vapor mixture with 15 mol % butanol (which is the vapor composition of an aqueous solution containing 2 wt % butanol, a typical concentration in an ABE fermentation broth, i.e., the composition of the gas obtained from gas stripping of an ABE broth) at 35 °C, the adsorption selectivity toward butanol was as high as 107. These results confirm that silicalite-1 quite selectively adsorbs hydrocarbons from vapor mixtures. To the best of our knowledge, this is the first comprehensive study on the adsorption of water and butanol in silicalite-1 from vapor phase.
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| 22. |
- Farzaneh, Amirfarrokh, et al.
(author)
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Adsorption of Water and Butanol in Silicalite-1 Film Studied with in Situ Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy
- 2015
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In: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 31:17, s. 4887-4894
-
Journal article (peer-reviewed)abstract
- Biobutanol produced by, e.g., acetone-butanol-ethanol (ABE) fermentation is a promising alternative to petroleum-based chemicals as, e.g., solvent and fuel. Recovery of butanol from dilute fermentation broths by hydrophobic membranes and adsorbents has been identified as a promising route. In this work, the adsorption of water and butanol vapor in a silicalite-1 film was studied using in situ attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy to better understand the adsorption properties of silicalite-1 membranes and adsorbents. Single-component adsorption isotherms were determined in the temperature range of 35-120 degrees C, and the Langmuir model was successfully fitted to the experimental data. The adsorption of butanol is very favorable compared to that of water. When the silicalite-1 film was exposed to a butanol/water vapor mixture with 15 mol % butanol (which is the vapor composition of an aqueous solution containing 2 wt % butanol, a typical concentration in an ABE fermentation broth, i.e., the composition of the gas obtained from gas stripping of an ABE broth) at 35 degrees C, the adsorption selectivity toward butanol was as high as 107. These results confirm that silicalite-1 quite selectively adsorbs hydrocarbons from vapor mixtures. To the best of our knowledge, this is the first comprehensive study on the adsorption of water and butanol in silicalite-1 from vapor phase.
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| 23. |
- Filippov, Andrei, et al.
(author)
-
Dynamic properties of water in silicalite-1 powder
- 2012
-
In: Magnetic Resonance Imaging. - : Elsevier BV. - 0730-725X .- 1873-5894. ; 30:7, s. 1022-1031
-
Journal article (peer-reviewed)abstract
- Self-diffusion of D2O in partially filled silicalite-1 crystals was studied at 25 degrees C by H-2 nuclear magnetic resonance (NMR) with bipolar field gradient pulses and longitudinal Eddy-current-delay. For the first time, reliable experimental diffusion data for this system were obtained. Analysis of NMR diffusion decays revealed the presence of a continuous distribution of apparent self-diffusion coefficients (SDCs) of water, ranging from 10(-7) to similar to 10(-10) m(2)/s, which include values much higher and lower than that of bulk water (similar to 10(-9) m(2)/s) in liquid phase. The observed distribution of SDC changes with variation of the diffusion time in the range of 10-200 ms. A two-site Karger exchange model was successfully fitted to the data. Finally, the water distribution and exchange in silicalite-1 pores were described by taking into account (a) a gas-like phase in the zeolite pores, a gas-like phase in mesopores and an intercrystalline gas-like phase and (b) intercrystalline liquid droplets with intermediate exchange rate with the other phases. The other phases experience fast exchange on the NMR diffusion time scale. Diffusion coefficients and mean residence times of water in some of these states were estimated.
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| 24. |
- Frykholm, Erik, 1985-, et al.
(author)
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Applicability of a supramaximal high-intensity interval training program for older adults previously not engaged in regular exercise : analyses of secondary outcomes from the Umeå HIT Study
- 2024
-
In: Psychology of Sport And Exercise. - : Elsevier. - 1469-0292 .- 1878-5476. ; 73
-
Journal article (peer-reviewed)abstract
- This analysis of secondary outcomes investigated the applicability of supramaximal high-intensity interval training (HIT) with individually prescribed external intensity performed on stationary bicycles. Sixty-eight participants with a median (min; max) age of 69 (66; 79), at the time not engaged in regular exercise were randomized to 25 twice-weekly sessions of supramaximal HIT (20-min session with 10 × 6-s intervals) or moderate-intensity training (MIT, 40-min session with 3 × 8-min intervals). The primary aim was outcomes on applicability regarding; adherence to prescribed external interval intensity, participant reported positive and negative events, ratings of perceived exertion (RPE 6–20), and affective state (Feeling Scale, FS -5–5). A secondary aim was to investigate change in exercise-related self-efficacy (Exercise Self-Efficacy Scale) and motivation (Behavioural Regulations in Exercise Questionnaire-2). Total adherence to the prescribed external interval intensity was [median (min; max)] 89 % (56; 100 %) in supramaximal HIT, and 100 % (95; 100 %) in MIT. The supramaximal HIT group reported 60 % of the positive (112 of 186) and 36 % of the negative (52 of 146) events. At the end of the training period, the median (min; max) session RPE was 15 (12; 17) for supramaximal HIT and 14 (9; 15) for MIT. As for FS, the median last within-session rating was 3 (−1; 5) for supramaximal HIT and 3 (1; 5) for MIT. Exercise-related motivation increased (mean difference in Relative Autonomy Index score = 1.54, 95 % CI [0.69; 2.40]), while self-efficacy did not change (mean difference = 0.55, 95 % CI [-0.75; 1.82]), regardless of group. This study provide support for supramaximal HIT in supervised group settings for older adults.
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| 25. |
- Grahn, Mattias, et al.
(author)
-
A novel experimental technique for estimation of molecular orientation in zeolite
- 2007
-
In: Studies in Surface Science and Catalysis. - 0167-2991. ; 170, s. 724-731
-
Journal article (peer-reviewed)abstract
- FTIR spectroscopy in combination with polarized light and an ATR probe coated with a b-oriented ZSM-5 film was for the first time used to determine the orientation of adsorbed molecules in the ZSM-5 structure. Two adsorbates were studied, n-hexane and p-xylene and the results agreed with previously reported results obtained by other experimental techniques.
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| 26. |
- Grahn, Mattias, et al.
(author)
-
Adsorption of n-hexane and p-xylene in thin silicalite-1 films studied by FTIR/ATR spectroscopy
- 2008
-
In: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 112:20, s. 7717-7724
-
Journal article (peer-reviewed)abstract
- Adsorption isotherms for p-xylene and n-hexane in silicalite-1 films with a thickness of 200 nm were determined at 323, 343, 368, 393, and 423 K using Fourier transform infrared/attenuated total reflection (FTIR/ATR) spectroscopy. For both adsorbates, the low-pressure data agreed with literature data for MFI powder and the estimated Henry's constant and adsorption enthalpy were close to previously reported results. The upper region of the n-hexane isotherm (p > 2 kPa at 323 K) was likely influenced by micropores in open grain boundaries, as expected for a polycrystalline film of small (<200 nm) crystals. As for n-hexane, the first part (0 ≤ p ≤ 65 Pa at 323 K) of the p-xylene isotherm agreed with data for powder. However, the saturation capacity was only about half of that previously reported for powders, which indicates that p-xylene molecules do not adsorb in the sinusoidal channels in the film. We speculate that the small crystals used in the present work may behave differently from the larger crystals in previous works. Another explanation for the lower saturation capacity may be the bonding of crystals to the supports, which are known to induce strain in the attached crystals.
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| 27. |
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| 28. |
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| 29. |
- Grahn, Mattias, et al.
(author)
-
Maxwell-Stefan modelling of High flux tubular silicalite-1 membranes for CO2 removal from CO2/H2 gas mixtures
- 2014
-
In: Journal of Membrane Science. - : Elsevier BV. - 0376-7388 .- 1873-3123. ; 471, s. 328-337
-
Journal article (peer-reviewed)abstract
- In this work, a Maxwell-Stefan model for high flux tubular silicalite-1 membranes for separation of CO2 from a CO2/H2 mixture was developed. The model concerns tubular membranes operating in a counter flow module and includes transport through flow-through defects in the silicalite-1 film and pressure drop over the graded alumina support. Adsorption and diffusion parameters for perfect silicalite-1 crystals were taken from literature. The flux and selectivity predicted by the model were in reasonably good agreement with experimentally observed data for a ZSM-5 membrane without any fitting of the model. However, the CO2 flux and selectivity measured experimentally for the ZSM-5 membrane were higher than that predicted by the model for a silicalite-1 membrane.The model was used to investigate a case with a 20 000 Nm3/d feed comprised of a 50/50 mixture of CO2/H2 at pressure of 25 bar and a membrane temperature of 296 K. The permeate pressure was 1 bar and 90% of the CO2 permeated the membrane. In this case, the membrane permselectivity and CO2 flux varied along the length of the tubes between 20–26 and 950–396 kg/(m2 h), respectively. Further, both defects and pressure drop over the support were shown to have an adverse effect on the selectivity, which indicates that membrane selectivity can be improved by reducing the flow-through defects and/or by preparing supports with less flow resistance. For a one-stage process, the required membrane area is as small as ca 0.85 m2 and the hydrogen loss through the membrane was 12.4%. For a two-stage process the required membrane area almost doubled to 1.6 m2, however the hydrogen loss through the second membrane is reduced to as little as 2.5%. In summary, this work shows that high flux zeolite membranes may be an interesting option for CO2 removal from synthesis gas.
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| 30. |
- Grahn, Mattias, et al.
(author)
-
Orientational analysis of adsorbates in molecular sieves by FTIR/ATR spectroscopy
- 2008
-
In: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 20:19, s. 6270-6276
-
Journal article (peer-reviewed)abstract
- ZnS ATR elements were coated with well-defined b-oriented ZSM-5 films by in situ growth. Both adsorption isotherms, as well as molecular orientation of p-xylene adsorbed in the films, were measured at 323 and 373 K by FTIR/ATR spectroscopy. The observed isotherms for the b-oriented ZSM-5 films in the present work were very similar to previously reported isotherms of supported MFI films, albeit the crystals in the latter films were aluminum free (silicalite-1) and orientated differently relative to the support surface than the crystals in the films studied in the present work. The novel technique facilitated, for the first time, the examination of how the tilt angle varies with loading and temperature. The data obtained in the present work showed that the p-xylene molecules were mainly oriented with their long axis parallel to the b-direction of the MFI crystals in concert with previously reported results based on FTIR microscopy, Monte Carlo simulations, NMR, and XRD data. At high concentrations, the tilt angle was in good agreement with observations by FTIR microscopy. It was also found that the orientation of the molecules changed with loading, this might be due to different adsorption geometries in the channel intersection as reported previously. The observed tilt angles may also be influenced from competitive adsorption on silanol groups, as was also indicated in the spectra. The results also indicate that the adsorption properties of zeolite films and powders may differ. Hence, adsorption parameters determined for zeolite powders may not necessarily be applicable to films.
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| 31. |
- Grahn, Mattias, et al.
(author)
-
Silicalite-1 coated ATR elements as sensitive chemical sensor probes
- 2005
-
In: Microporous and Mesoporous Materials. - : Elsevier BV. - 1387-1811 .- 1873-3093. ; 81:1-3, s. 357-363
-
Journal article (peer-reviewed)abstract
- A novel sensitive chemical sensor probe has been fabricated. The sensor principle is based on silicalite-1 coated ATR (attenuated total reflection) elements and FTIR spectroscopy. The microporous silicalite-1 film enriches the analyte to the probe surface, thus increasing the sensitivity. At a relative pressure of n-hexane in helium of 6 × 10−5 the sensitivity of the probe is approximately 85 times higher for the silicalite-1 coated element compared to a 10 cm transmission gas cell and ca. 180 times higher compared to an uncoated element. The performance of the probe is illustrated by determination of an adsorption isotherm for n-hexane in silicalite-1.
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| 32. |
- Grahn, Mattias, et al.
(author)
-
Small ZSM-5 crystals with low defect density as an effective catalyst for conversion of methanol to hydrocarbons
- 2020
-
In: Catalysis Today. - : Elsevier B.V.. - 0920-5861 .- 1873-4308. ; 345, s. 136-146
-
Journal article (peer-reviewed)abstract
- This work presents the synthesis of nearly defect-free ZSM-5 nanosized crystals, prepared in fluoride medium by seeding with silicalite-1. This material was carefully characterized and its catalytic performances in the methanol to hydrocarbons (MTH) reaction were assessed. Such fluoride-based material was compared to a reference ZSM-5, produced through a conventional alkaline synthesis but from the same seeding. Despite both the materials show closely identical morphology and they have a comparable acid site population, the catalyst prepared using the fluoride route showed significantly longer lifetime in MTH compared to the catalyst prepared using conventional synthesis at high pH. The slower deactivation for the samples prepared using the fluoride route was ascribed, thanks to a thorough in situ IR spectroscopy study, to its lower density of internal defects. According to the UV-Raman characterization of coke on the spent catalyst, the fluoride-based ZSM-5 catalyst produces less molecular coke species, most probably because of the absence of enlarged cavities/channels as due to the presence of internal defects. On the basis of these observations, the deactivation mechanism in the ZSM-5 synthesized by fluoride medium could be mostly related to the deposition of an external layer of bulk coke, whereas in the alkali-synthesized catalyst an additional effect from molecular coke accumulating within the porous network accelerates the deactivation process.
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| 33. |
- Granström, Fredrik, et al.
(author)
-
Test-retest reliability of the twenty-five-hole peg test in patients who had a stroke
- 2019
-
In: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 9:12
-
Journal article (peer-reviewed)abstract
- OBJECTIVES: Weaknesses of the nine-hole peg test include high floor effects and a result that might be difficult to interpret. In the twenty-five-hole peg test (TFHPT), the larger number of available pegs allows for the straightforward counting of the number of pegs inserted as the result. The TFHPT provides a comprehensible result and low floor effects. The objective was to assess the test-retest reliability of the TFHPT when testing persons with stroke. A particular focus was placed on the absolute reliability, as quantified by the smallest real difference (SRD). Complementary aims were to investigate possible implications for how the TFHPT should be used and for how the SRD of the TFHPT performance should be expressed.DESIGN: This study employed a test-retest design including three trials. The pause between trials was approximately 10-120 s.PARTICIPANTS, SETTING AND OUTCOME MEASURE: Thirty-one participants who had suffered a stroke were recruited from a group designated for constraint-induced movement therapy at outpatient clinics. The TFHPT result was expressed as the number of pegs inserted.METHODS: Absolute reliability was quantified by the SRD, including random and systematic error for a single trial, SRD2.1, and for an average of three trials, SRD2.3. For the SRD measures, the corresponding SRD percentage (SRD%) measure was also reported.RESULTS: The differences in the number of pegs necessary to detect a change in the TFHPT for SRD2.1 and SRD2.3 were 4.0 and 2.3, respectively. The corresponding SRD% values for SRD2.1 and SRD2.3 were 36.5% and 21.3%, respectively.CONCLUSIONS: The smallest change that can be detected in the TFHPT should be just above two pegs for a test procedure including an average of three trials. The use of an average of three trials compared with a single trial substantially reduces the measurement error.TRIAL REGISTRATION NUMBER: ISRCTN registry, reference number ISRCTN24868616.
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| 34. |
- Gustafsson, Oscar, et al.
(author)
-
Photoluminescence photoresponse from InSb/InAs-based quantum dot structures
- 2012
-
In: Optics Express. - : Optical Society of America. - 1094-4087. ; 20:19, s. 21264-71
-
Journal article (peer-reviewed)abstract
- InSb-based quantum dots grown by metal-organic vapor-phase epitaxy (MOVPE) on InAs substrates are studied for use as the active material in interband photon detectors. Long-wavelength infrared (LWIR) photoluminescence is demonstrated with peak emission at 8.5 μm and photoresponse, interpreted to originate from type-II interband transitions in a p-i-n photodiode, was measured up to 6 μm, both at 80 K. The possibilities and benefits of operation in the LWIR range (8-12 μm) are discussed and the results suggest that InSb-based quantum dot structures can be suitable candidates for photon detection in the LWIR regime.
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| 35. |
- Gustavsson, Inger M., et al.
(author)
-
Clinical validation of the HPVIR high-risk HPV test on cervical samples according to the international guidelines for human papillomavirus DNA test requirements for cervical cancer screening
- 2019
-
In: Virology Journal. - : Springer Science and Business Media LLC. - 1743-422X. ; 16:1
-
Journal article (peer-reviewed)abstract
- BackgroundThe indicating FTA card is a dry medium used for collection of cervical samples. HPVIR is a multiplex real-time PCR test that detects 12 high-risk human papillomavirus types (hrHPV) and provides single genotype information for HPV16, − 31, − 35, − 39, − 51, − 56, and − 59 and pooled type information for HPV18/45 and HPV33/52/58. The aim of this study was to evaluate whether a strategy with cervical samples collected on the FTA card and subsequently analysed with the HPVIR test complies with the criteria of the international guidelines for a clinically validated method for cervical screening.MethodsWe performed a non-inferiority test comparing the clinical sensitivity and specificity of the candidate test (FTA card and HPVIR) with a clinically validated reference test (Cobas® HPV test) based on liquid-based cytology (LBC) samples. Two clinical samples (LBC and FTA) were collected from 896 participants in population-based screening. For evaluation of the specificity we used 799 women without ≥ CIN2, and for clinical sensitivity we used 67 women with histologically confirmed ≥ CIN2. The reproducibility was studied by performing inter- and intra-laboratory tests of 558 additional clinical samples.ResultsThe clinical sensitivity and specificity for samples collected on the FTA card and analysed using the HPVIR test were non-inferior to samples analysed with the Cobas® HPV test based on LBC samples (non-inferiority test score, p = 1.0 × 10− 2 and p = 1.89 × 10− 9, respectively). Adequate agreement of > 87% was seen in both the intra- and inter-laboratory comparisons.ConclusionsSamples collected on the indicating FTA card and analysed with HPVIR test fulfil the requirements of the international guidelines and can therefore be used in primary cervical cancer screening.
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| 36. |
- Gyger, Samuel, et al.
(author)
-
Metropolitan single-photon distribution at 1550 nm for random number generation
- 2022
-
In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 121:19, s. 194003-
-
Journal article (peer-reviewed)abstract
- Quantum communication networks will connect future generations of quantum processors, enable metrological applications, and provide security through quantum key distribution. We present a testbed that is part of the municipal fiber network in the greater Stockholm metropolitan area for quantum resource distribution through a 20 km long fiber based on semiconductor quantum dots emitting in the telecom C-band. We utilize the service to generate random numbers passing the NIST test suite SP800-22 at a subscriber 8 km outside of the city with a bit rate of 23.4 kbit/s.
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| 37. |
- Gyger, Samuel, et al.
(author)
-
Metropolitan Single-Photon Distribution at 1550 nm for Random Number Generation
- 2023
-
In: 2023 Conference on Lasers and Electro-Optics, CLEO 2023. - : Institute of Electrical and Electronics Engineers Inc..
-
Conference paper (peer-reviewed)abstract
- Quantum communication networks are used for QKD and metrological applications. We present research connecting two nodes ≈ 20 kilometers apart over the municipal fiber network using semiconductor quantum dots emitting at 1550 nm.
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| 38. |
- Gyger, Samuel, et al.
(author)
-
Reconfigurable frequency coding of triggered single photons in the telecom C–band
- 2019
-
In: Optics Express. - : OSA. - 1094-4087. ; 27:10, s. 14400-14406
-
Journal article (peer-reviewed)abstract
- In this work, we demonstrate reconfigurable frequency manipulation of quantum states of light in the telecom C–band. Triggered single photons are encoded in a superposition state of three channels using sidebands up to 53 GHz created by an off-the-shelf phase modulator. The single photons are emitted by an InAs/GaAs quantum dot grown by metal-organic vapor-phase epitaxy within the transparency window of the backbone fiber optical network. A cross-correlation measurement of the sidebands demonstrates the preservation of the single photon nature; an important prerequisite for future quantum technology applications using the existing telecommunication fiber network.
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| 39. |
- Hedlund, Ann, et al.
(author)
-
Assessing motivation for work environment improvements : internal consistency, reliability and factorial structure
- 2010
-
In: Journal of Safety Research. - : Elsevier. - 0022-4375 .- 1879-1247. ; 41:2, s. 145-151
-
Journal article (peer-reviewed)abstract
- Problem. Workers’ motivation to actively take part in improvements to the work environment is assumed to be important for the efficiency of investments for that purpose. That gives rise to the need for a tool to measure this motivation.Metho.d A questionnaire to measure motivation for improvements to the work environment has been designed. Internal consistency and test-retest reliability of the domains of the questionnaire has been measured, and the factorial structure has been explored, from the answers of 113 employees. Results The internal consistency is high (0.94), as well as the correlation for the total score (0.84). Three factors are identified accounting for 61.6% of the total variance.Discussion. The questionnaire can be a useful tool in improving intervention methods. The expectation is that the tool thereby can be useful, particularly with the aim of improving efficiency of companies’ investments for work environment improvements.
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| 40. |
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| 41. |
- Hedlund, Ann, et al.
(author)
-
Attraktivt arbete
- 2004
-
In: Forskningsdag, Högskolan Dalarna. - Borlänge : Högskolan Dalarna.
-
Conference paper (other academic/artistic)
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| 42. |
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| 43. |
- Hedlund, Ann, et al.
(author)
-
En studie av ungdomars och anställdas syn på arbete i två kommuner i Dalarna
- 2003
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In: Arbete och hälsa. - 0346-7821. ; 2, s. 52-
-
Journal article (peer-reviewed)abstract
- A study of youths and employees opinions on work in two municipalities in Dalarna During the second half of the 1980:s attention was drawn to the difficulties for the industry to recruite youths. The difficulties to recruite had been made worse partly as a result of the decreasing batch of youths, partly of youths negative attitudes towards industrial work. When the state of the market turned to increased prosperity during the second half of the 1990:s, the difficulties in recruiting returned to... mer the agenda. The primary purpose of the study provides a data foundation for discussions in a development project aimed at increasing the attractiveness of manufacturing industry as a workplace. Other purposes concerns youths and employees opinions on ideal work and on industrial work. The study was turned towards youths in the ninth grade and to employees in small engineering workshops and in loghouse firms. The study was delimited to the municipalities Avesta and Rättvik in Dalarna, Sweden. The youths had higher estimates than the employees in both ideal and industrial work. The working environment, including physical, social and working organisational aspects, is the one aspect that the youths has put forward as most important for the firms to improve. Improvement in the working environment may be a suitable strategy to increase the interest for manufacturing and industrial work. A result of the study is that the environment and the treatment that youths experience in the contact with industry firms, e.g. by practical occupational experience, educational visits etc., has great importance for the youths opinion on work within the manufacturing industry.
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| 44. |
- Hedlund, Ann, et al.
(author)
-
Picking Apples
- 2009
-
In: 7:th Seminar on Worklife Development. - Lappeenranta and Ruokolahti, Finland.
-
Conference paper (other academic/artistic)abstract
- The Attractive Work model was developed by Theme Working Life (Åteg, Hedlund m fl. 2004). To be able to measure attractiveness a questionnaire was developed from the model (Högskolan Dalarna 2004). The overall aim with the questionnaire is to provide a basis for the development of attractive work and workplaces. A change process with the questionnaire as a base has been developed in research and development projects together with SMEs. When following up the process at one company the thoughts about using the model itself, in the form as a tree, as a basis for development of attractive work and workplaces were born. The argument for using the model directly instead of results from the questionnaire was that in small groups, the employees can easily participate in immediate discussions based on the contents of the model. This results in a higher degree of involvement, quicker feedback and a visual representation that is easy to grasp and communicate. Development of a new method, called Picking Apples, has begun. So far a pilot study has been conducted at one company. The specific aim with the method is to raise the insight about the importance to better take care of the human resources for the organizations sustainability. This creates motivation to develop work for increased attractiveness and increased competitiveness. The Picking Apples method implies discussions around Attractive Work. One or more groups of employees discuss attractivity in different steps supported by a process leader. A whiteboard where the tree Attractive Work is drawn up is used as support to the discussion. The employees talk about what they perceive as attractive in their work, why that makes their work attractive and what can be done to increase the attractiveness. The most important qualities in the work are identified. The results of the discussions are documented with a camera. Afterwards the results of the discussions are presented to the manager. The results from the pilot study showed that the employees were engaged, and the manager appreciated the method and said that it had resulted in a better dialogue between the manager and the employees. Högskolan Dalarna (2004). Frågor om Attraktivt Arbete. Borlänge: 5. Åteg, M., A. Hedlund, m fl. (2004). Attraktivt arbete. Från anställdas uttalanden till skapandet av en modell. Stockholm, Arbetslivsinstitutet.
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| 45. |
- Hedlund, Ann, et al.
(author)
-
To monitor motivation for work place improvements
- 2009
-
In: 7:th Seminar on Worklife Development. - Lappeenranta and Ruokolahti, Finland.
-
Conference paper (other academic/artistic)abstract
- This presentation is a short summary of an article sent to Journal of Safety Research (Hedlund, Åteg m fl.). Knowledge about hazards in working life and ways to measure, eliminate and minimize them is growing. However, there are obstacles between this knowledge and actions to reduce workers’ exposure to hazards. A common problem is that the workers not are motivated to use available technology and knowledge. It is assumed that the workers’ motivation to actively take part in improvements to the work environment is important for the efficiency of investments for that purpose. With this as a background has a questionnaire that measure motivation for improvements to the work environment been developed. The objective is to present the internal consistency and test-retest reliability of the questionnaire. A second objective is to explore the factorial structure of the instrument comprising different aspects of motivation for work environment improvements.
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| 46. |
- Hedlund, Julia, 1975, et al.
(author)
-
Change of Colloidal and Surface Properties of Mytilus edulis Foot Protein 1 in the Presence of an Oxidation (NaIO4) or a Complex-Binding (Cu2+) Agent
- 2009
-
In: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 10:4, s. 845-849
-
Journal article (peer-reviewed)abstract
- Quartz crystal microbalance with dissipation monitoring (QCM-D) was used to study the viscoelastic properties of the blue mussel, Mytilus edulis, foot protein 1 (Mefp-1) adsorbed on modified hydrophobic gold surfaces. The change in viscoelasticity was studied after addition of Cu2+ and Mn2+, which theoretically could induce metal complex formation with 3,4-dihydroxyphenylalanine (DOPA) moieties. We also used NaIO4, a nonmetal oxidative agent known to induce di-DOPA formation. Reduction in viscoelasticity of adsorbed Mefp-1 followed the order of NaIO4 > Cu2+ > buffer control > Mn2+. We also studied the formation of molecular aggregates of Mefp-1 in solution with the use of dynamic light scattering (DLS). We found that addition of Cu2+, but not Mn2+, induced the formation of larger DLS-detectable aggregates. Minor aggregate formation was found with NaIO4. With the analytical resolution of small angle X-ray scattering (SAXS), we could detect differences in the molecular structure between NaIO4- and Cu2+-treated Mefp-1 aggregates. We concluded from this study that Cu2+ could participate in intermolecular cross-linking of the Mefp-1 molecule via metal complex formation. Metal incorporation in the protein most likely increases the abrasion resistance of the Mefp-1 layer. NaIO4, on the other hand, resulted in mainly intramolecular formation of di-DOPA, but failed to induce larger intermolecular aggregation phenomena. The described methodological combination of surface sensitive methods, like QCM-D, and bulk sensitive methods, like DLS and SAXS, generates high resolution results and is an attractive platform to investigate intra- and intermolecular aspects of assembly and cross-linking of the Mefp proteins.
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| 47. |
- Hedlund, Jonas, et al.
(author)
-
Controlling diffusion resistance, selectivity and deactivation of ZSM-5 catalysts by crystal thickness and defects
- 2022
-
In: Journal of Catalysis. - : Elsevier. - 0021-9517 .- 1090-2694. ; 410, s. 320-332
-
Journal article (peer-reviewed)abstract
- A systematic investigation of two sets of defect free and defective ZSM-5 crystals with controlled thickness (T) between 30 and 400 nm and of their performances in methanol conversion was reported for the first time in the present work. The defect free ZSM-5 crystals with a thickness of 35 nm are by far the smallest ever reported and displayed superior activity, stability and selectivity to slower diffusing compounds, which resulted in high yield of e.g. gasoline and the 1,2,4-trimethylbenzene isomer with high octane number, as compared to the other studied catalysts. Almost only products forming in the zeolite pores were detected and consequently, the external surface must be nearly inactive. Strong correlations between T and deactivation rate were observed. Thick crystals deactivated much faster than thin crystals, probably due to formation of carbon species in the zeolite pores, which results in pronounced percolation effects and faster deactivation of the former. At comparable thickness, crystals with defects deactivated much faster than defect free crystals, due to formation of additional small molecular coke species in the former. Strong correlations between T and selectivity were also observed and assigned to control of diffusion resistance by crystal thickness.
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| 48. |
- Hedlund, Jonas, et al.
(author)
-
Mass transport in porous media from first principles : an experimental and theoretical study
- 2012
-
In: Journal of Membrane Science. - : Elsevier BV. - 0376-7388 .- 1873-3123. ; 415-416, s. 271-277
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Journal article (peer-reviewed)abstract
- In the present work, the mass transport of helium through zeolite is experimentally determined by measuring the flow of helium through a zeolite membrane. By using a mathematical model, the mass transport through defects was accounted for to arrive at mass transport through zeolite pores. For the first time, we could thereby experimentally show that the mass transport of helium in zeolite pores is strongly controlled by the amount and location of hydrocarbons in the zeolite pores and varies several orders of magnitude. The mass transport of helium in ZSM-5 zeolite pores is first reduced gradually more than one order of magnitude when the loading of n-hexane is increased from 0 to 47% of saturation. As the loading of n-hexane is further increased to 54% of saturation, the mass transport of helium in the zeolite pores is further reduced abruptly by more than two orders of magnitude. This gradual decrease followed by an abrupt decrease of mass transport is caused by adsorption of n-hexane in the zeolite pores. In a similar yet different fashion, the mass transport of helium in the zeolite pores is reduced abruptly by almost two orders of magnitude when the loading of benzene is increased from 0 to 19% of saturation due to adsorption of benzene in the pore intersections. Effective medium approximation percolation models with parameters estimated using density functional theory employing the local density approximation, i.e. models with no adjustable parameters and the most sophisticated theory yet applied to this system, can adequately describe the experimental observations.
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| 49. |
- Hedlund, Mattias, 1968-
(author)
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Biomechanical and neural aspects of eccentric and concentric muscle performance in stroke subjects : Implications for resistance training
- 2012
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Doctoral thesis (other academic/artistic)abstract
- Muscle weakness is one of the major causes of post-stroke disability. Stroke rehabilitation programs now often incorporate the same type of resistance training that is used for healthy subjects; however, the training effects induced from these training strategies are often limited for stroke patients. An important resistance training principle is that an optimal level of stress is exerted on the neuromuscular system, both during concentric (shortening) and eccentric (lengthening) contractions. One potential problem for post-stroke patients might be difficulties achieving sufficient levels of stress on the neuromuscular system. This problem may be associated with altered muscular function after stroke. In healthy subjects, maximum strength during eccentric contractions is higher than during concentric contractions. In individuals with stroke, this difference in strength is often increased. Moreover, it has also been shown that individuals with stroke exhibit alteration with respect to how the strength varies throughout the range of motion. For example, healthy subjects exhibit a joint specific torque-angle relationship that normally is the same irrespective of contraction mode and contraction velocity. In contrast, individuals with stroke exhibit an overall change of the torque-angle relationship. This change, as described in the literature, consists of a more pronounced strength loss at short muscle length. In individuals with stroke, torque-angle relationships are only partially investigated and so far these relationships have not been analysed using testing protocols that include eccentric, isometric, and concentric modes of contraction. This thesis investigates the torque-angle relationship of elbow flexors in subjects with stroke during all three modes of contractions – isometric, concentric, and eccentric – and the relative loading throughout the range of movement during a resistance exercise. In addition, this thesis studies possible central nervous system mechanisms involved in the control of muscle activation during eccentric and concentric contractions. The torque-angle relationship during maximum voluntary elbow flexion was examined in stroke subjects (n=11), age-matched healthy subjects (n=11), and young subjects (n=11) during different contraction modes and velocities. In stroke subjects, maximum torque as well as the torque angle relationship was better preserved during eccentric contractions compared to concentric contractions. Furthermore, the relative loading during a resistance exercise at an intensity of 10RM (repetition maximum) was examined. Relative loading throughout the concentric phase of the resistance exercise, expressed as percentage of concentric torque, was found to be similar in all groups. However, relative loading during the eccentric contraction phase, expressed as the percentage of eccentric isokinetic torque, was significantly lower for the stroke group. In addition, when related to isometric maximum voluntary contraction, the loading for the stroke group was significantly lower than for the control groups during both the concentric and eccentric contraction phases.Functional magnetic resonance imaging was used to examine differences between recruited brain regions during the concentric and the eccentric phase of imagined maximum resistance exercise of the elbow flexors (motor imagery) in young healthy subjects (n=18) and in a selected sample of individuals with stroke (n=4). The motor and premotor cortex was less activated during imagined maximum eccentric contractions compared to imagined maximum concentric contraction of elbow flexors. Moreover, BA44 in the ventrolateral prefrontal cortex, a brain area that has been shown to be involved in inhibitory control of motor activity, was additionally recruited during eccentric compared to concentric conditions. This pattern was evident only on the contralesional (the intact hemisphere) in some of the stroke subjects. On the ipsilesional hemisphere, the recruitment in ventrolateral prefrontal cortex was similar for both modes of contractions. Compared to healthy subjects, the stroke subjects exhibited altered muscular function comprising a specific reduction of torque producing capacity and deviant torque-angle relationship during concentric contractions. Therefore, the relative training load during the resistance exercise at a training intensity of 10RM was lower for subjects with stroke. Furthermore, neuroimaging data indicates that the ventrolateral prefrontal cortex may be involved in a mechanism that modulates cortical motor drive differently depending on mode of the contractions. This might partly be responsible for why it is impossible to fully activate a muscle during eccentric contractions. Moreover, among individuals with stroke, a disturbance of this system could also lie behind the lack of contraction mode-specific modulation of muscle activation that has been found in this population. The altered neuromuscular function evident after a stroke means that stroke victims may find it difficult to supply a sufficient level of stress during traditional resistance exercises to promote adaptation by the neuromuscular system. This insufficiency may partially explain why the increase in strength, in response to conventional resistance training, often has been found to be low among subjects with stroke.
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| 50. |
- Hedlund, Mattias, et al.
(author)
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Development and Feasibility of a Regulated, Supramaximal High-Intensity Training Program Adapted for Older Individuals
- 2019
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In: Frontiers in Physiology. - : Frontiers Media S.A.. - 1664-042X. ; 10
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Journal article (peer-reviewed)abstract
- Background: High-intensity training (HIT) with extremely short intervals (designated here as supramaximal HIT) is a time-efficient training method for health and performance. However, a protocol for regulation and control of intensity is missing, impeding implementation in various groups, such as older individuals.Methods: This study presents the development and characteristics of a novel training protocol with regulated and controlled supramaximal intervals adapted for older people. Using both quantitative and qualitative analyses, we explored the feasibility of the program, performed in a group training setting, with physically active older individuals (aged 65–75, n = 7; five women). The developed supramaximal HIT program consisted of 10 × 6 s cycle sprint intervals with ∼1 min of active recovery with the following key characteristics: (1) an individual target power output was reached and maintained during all intervals and regulated and expressed as the percentage of the estimated maximum mean power output for the duration of the interval (i.e., 6 s); (2) pedaling cadence was standardized for all participants, while resistance was individualized; and (3) the protocol enabled controlled and systematic adjustments of training intensity following standardized escalation criteria.Aim: Our aim was to test the feasibility of a novel training regimen with regulated and controlled supramaximal HIT, adapted for older people. The feasibility criteria for the program were to support participants in reaching a supramaximal intensity (i.e., power output > 100% of estimated VO2 max), avoid inducing a negative affective response, and have participants perceive it as feasible and acceptable.Results: All feasibility criteria were met. The standardized escalation procedure provided safe escalation of training load up to a supramaximal intensity (around three times the power output at estimated VO2 max). The participants never reported negative affective responses, and they perceived the program as fun and feasible.Conclusion: This novel program offers a usable methodology for further studies on supramaximal HIT among older individuals with different levels of physical capacity. Future research should explore the effects of the program in various populations of older people and their experiences and long-term adherence compared with other forms of training.
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