| 1. |
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| 2. |
- Aili, Katarina, 1980-, et al.
(författare)
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Reliability of Actigraphy and Subjective Sleep Measurements in Adults : The Design of Sleep Assessments
- 2017
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Ingår i: Journal of Clinical Sleep Medicine (JCSM). - Darien, IL : The American Academy of Sleep Medicine. - 1550-9389 .- 1550-9397. ; 13:1, s. 39-47
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Tidskriftsartikel (refereegranskat)abstract
- STUDY OBJECTIVES: The aim of the study was to investigate how many nights of measurement are needed for a reliable measure of sleep in a working population including adult women and men.METHODS: In all, 54 individuals participated in the study. Sleep was assessed for 7 consecutive nights using actigraphy as an objective measure, and the Karolinska sleep diary for a subjective measure of quality. Using intra-class correlation and the Spearman-Brown formula, calculations of how many nights of measurements were required for a reliable measure were performed. Differences in reliability according to whether or not weekend measurements were included were investigated. Further, the correlation between objectively (actigraphy) measured sleep and subjectively measured sleep quality was studied over the different days of the week.RESULTS/CONCLUSIONS: The results concerning actigraphy sleep measures suggest that data from at least 2 nights are to be recommended when assessing sleep percent and at least 5 nights when assessing sleep efficiency. For actigraphy-measured total sleep time, more than 7 nights are needed. At least 6 nights of measurements are required for a reliable measure of self-reported sleep. Fewer nights (days) are required if measurements include only week nights. Overall, there was a low correlation between the investigated actigraphy sleep parameters and subjective sleep quality, suggesting that the two methods of measurement capture different dimensions of sleep.
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| 3. |
- Andersson, Ragni, et al.
(författare)
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Minskade växtnäringsförlusteroch växthusgasutsläpp till 2016 : – förslag till handlingsprogram för jordbruket
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Jordbruksverket har haft i uppdrag att ta fram ett förslag till handlingsprogram förminskade växtnäringsförluster och växthusgasutsläpp. Förslaget ska gälla perioden2011-2016, med utblick till 2020.Det här är första gången som Jordbruksverket presenterar ett samlat handlingsprogramför växtnäring och klimat. Utgångspunkten i arbetet har dels varit vad som utifråndagens kunskap är tekniskt möjligt att göra på gårdsnivå, dels vår kunskap om vilkaförändringar som låter sig styras av samhället med administrativa eller ekonomiskastyrmedel. En annan avgörande utgångspunkt har varit att fokusera på åtgärder som kanvidtas i jordbruket utan att dagens produktionsinriktning och omfattning förändras.
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| 4. |
- Arakelian, Erebouni, 1973-, et al.
(författare)
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How Human Resources Index, Relational Justice, and Perceived Productivity Change after Reorganization at a Hospital in Sweden That Uses a Structured Support Model for Systematic Work Environment Management
- 2021
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Ingår i: International Journal of Environmental Research and Public Health. - : MDPI. - 1661-7827 .- 1660-4601. ; 18:21
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Tidskriftsartikel (refereegranskat)abstract
- To facilitate systematic work environment management, which should be a natural part of business development, a structured support model was developed. The Stamina model has previously been used in Swedish municipalities, showing positive results. The aim was to study how the Human Resources Index (HRI), relational justice, short-term recovery and perceived productivity changed in a recently reorganised perioperative setting in a hospital in Sweden that uses a structured support model for systematic work environment management. A longitudinal design that took measurements at four time points was used in a sample of 500 employees in a perioperative hospital department. The results for the overall sample indicated a positive trend in the HRI (Mt1 = 48.5, SDt1 = 22.5; Mt3 = 56.7, SDt1 = 21.2; p < 0.001). Perceived health-related production loss (Mdt1 = 2, IQR = 3; Mdt3 = 0, IQR = 3; p < 0.001) and perceived work environment-related production loss (Mdt1 = 2, IQR = 3; Mdt3 = 0, IQR = 4; p < 0.001) showed major improvements. Short-term recovery showed a minor improvement (Mt1 = 2.61, SDt1 = 1.33; Mt3 = 2.65, SDt3 = 1.22; p = 0.872). In conclusion, the implementation of the Stamina model, of which the HRI constitutes an important part, seems to be a helpful tool to follow-up on work environment processes, and minimise production losses due to health and work environment-related issues.
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| 5. |
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| 6. |
- Bolam, Kate, et al.
(författare)
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Association between change in cardiorespiratory fitness and prostate cancer incidence and mortality in 57 652 Swedish men.
- 2024
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Ingår i: British Journal of Sports Medicine. - : BMJ Publishing Group Ltd. - 0306-3674 .- 1473-0480. ; 58:7, s. 366-372
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To examine the associations between changes in cardiorespiratory fitness (CRF) in adulthood and prostate cancer incidence and mortality.METHODS: In this prospective study, men who completed an occupational health profile assessment including at least two valid submaximal CRF tests, performed on a cycle ergometer, were included in the study. Data on prostate cancer incidence and mortality were derived from national registers. HRs and CIs were calculated using Cox proportional hazard regression with inverse probability treatment weights of time-varying covariates.RESULTS: During a mean follow-up time of 6.7 years (SD 4.9), 592 (1%) of the 57 652 men were diagnosed with prostate cancer, and 46 (0.08%) died with prostate cancer as the primary cause of death. An increase in absolute CRF (as % of L/min) was associated with a reduced risk of prostate cancer incidence (HR 0.98, 95% CI 0.96 to 0.99) but not mortality, in the fully adjusted model. When participants were grouped as having increased (+3%), stable (±3%) or decreased (-3%) CRF, those with increased fitness also had a reduced risk of prostate cancer incidence compared with those with decreased fitness (HR 0.65, 95% CI 0.49 to 0.86), in the fully adjusted model.CONCLUSION: In this study of employed Swedish men, change in CRF was inversely associated with risk of prostate cancer incidence, but not mortality. Change in CRF appears to be important for reducing the risk of prostate cancer.
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| 7. |
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| 8. |
- Brandbyge, Mads, et al.
(författare)
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First-principles NEGF-DFT transport
- 2006
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Ingår i: Report on multiscale approaches to modelling for nanotechnology.
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 9. |
- Che, Karlhans F., et al.
(författare)
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Complex Involvement of Interleukin-26 in Bacterial Lung Infection
- 2021
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Ingår i: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 12, s. 1-18
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Tidskriftsartikel (refereegranskat)abstract
- Pneumonia is a global cause of mortality, and this provides a strong incentive to improve the mechanistic understanding of innate immune responses in the lungs. Here, we characterized the involvement of the cytokine interleukin (IL)-26 in bacterial lung infection. We observed markedly increased concentrations of IL-26 in lower airway samples from patients with bacterial pneumonia and these correlated with blood neutrophil concentrations. Moreover, pathogen-associated molecular patterns (PAMPs) from both Gram-negative and -positive bacteria increased extracellular IL-26 concentrations in conditioned media from human models of alveolar epithelial cells, macrophages, and neutrophils in vitro. Stimulation with IL-26 inhibited the inherent release of neutrophil elastase and myeloperoxidase in unexposed neutrophils. This stimulation also inhibited the expression of activity makers in neutrophils exposed to Klebsiella pneumoniae. In addition, priming of human lung tissue ex vivo with exogenous IL-26 potentiated the endotoxin-induced increase in mRNA for other cytokines involved in the innate immune response, including the master Th17-regulator IL-23 and the archetype inhibitory cytokine IL-10. Finally, neutralization of endogenous IL-26 clearly increased the growth of Klebsiella pneumoniae in the macrophage culture. These findings suggest that IL-26 is involved in bacterial lung infection in a complex manner, by modulating critical aspects of innate immune responses locally and systemically in a seemingly purposeful manner and by contributing to the killing of bacteria in a way that resembles an antimicrobial peptide. Thus, IL-26 displays both diagnostic and therapeutic potential in pneumonia and deserves to be further evaluated in these respects.
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| 10. |
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| 11. |
- Ekblom Bak, Elin, 1981-, et al.
(författare)
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Association Between Cardiorespiratory Fitness and Cancer Incidence and Cancer-Specific Mortality of Colon, Lung, and Prostate Cancer Among Swedish Men.
- 2023
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Ingår i: JAMA Network Open. - : American Medical Association (AMA). - 2574-3805. ; 6:6
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Tidskriftsartikel (refereegranskat)abstract
- IMPORTANCE: Cardiorespiratory fitness (CRF) levels appear to be an important risk factor for cancer incidence and death.OBJECTIVES: To examine CRF and prostate, colon, and lung cancer incidence and mortality in Swedish men, and to assess whether age moderated any associations between CRF and cancer.DESIGN, SETTING, AND PARTICIPANTS: A prospective cohort study was conducted in a population of men who completed an occupational health profile assessment between October 1982 and December 2019 in Sweden. Data analysis was performed from June 22, 2022, to May 11, 2023.EXPOSURE: Cardiorespiratory fitness was assessed as maximal oxygen consumption, estimated using a submaximal cycle ergometer test.MAIN OUTCOMES AND MEASURES: Data on prostate, colon, and lung cancer incidence and mortality were derived from national registers. Hazard ratios (HRs) and 95% CIs were calculated using Cox proportional hazards regression.RESULTS: Data on 177 709 men (age range, 18-75 years; mean [SD] age, 42 [11] years; mean [SD] body mass index, 26 [3.8]) were analyzed. During a mean (SD) follow-up time of 9.6 (5.5) years, a total of 499 incident cases of colon, 283 of lung, and 1918 of prostate cancer occurred, as well as 152 deaths due to colon cancer, 207 due to lung cancer, and 141 deaths due to prostate cancer. Higher levels of CRF (maximal oxygen consumption as milliliters per minute per kilogram) were associated with a significantly lower risk of colon (HR, 0.98, 95% CI, 0.96-0.98) and lung cancer (HR, 0.98; 95% CI, 0.96-0.99) incidence, and a higher risk of prostate cancer incidence (HR, 1.01; 95% CI, 1.00-1.01). Higher CRF was associated with a lower risk of death due to colon (HR, 0.98; 95% CI, 0.96-1.00), lung (HR, 0.97; 95% CI, 0.95-0.99), and prostate (HR, 0.95; 95% CI, 0.93-0.97) cancer. After stratification into 4 groups and in fully adjusted models, the associations remained for moderate (>35-45 mL/min/kg), 0.72 (0.53-0.96) and high (>45 mL/min/kg), 0.63 (0.41-0.98) levels of CRF, compared with very low (<25 mL/min/kg) CRF for colon cancer incidence. For prostate cancer mortality, associations remained for low (HR, 0.67; 95% CI, 0.45-1.00), moderate (HR, 0.57; 95% CI, 0.34-0.97), and high (HR, 0.29; 95% CI, 0.10-0.86) CRF. For lung cancer mortality, only high CRF (HR, 0.41; 95% CI, 0.17-0.99) was significant. Age modified the associations for lung (HR, 0.99; 95% CI, 0.99-0.99) and prostate (HR, 1.00; 95% CI, 1.00-1.00; P < .001) cancer incidence, and for death due to lung cancer (HR, 0.99; 95% CI, 0.99-0.99; P = .04).CONCLUSIONS AND RELEVANCE: In this cohort of Swedish men, moderate and high CRF were associated with a lower risk of colon cancer. Low, moderate, and high CRF were associated with lower risk of death due to prostate cancer, while only high CRF was associated with lower risk of death due to lung cancer. If evidence for causality is established, interventions to improve CRF in individuals with low CRF should be prioritized.
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| 12. |
- Enberg, Sofia, et al.
(författare)
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Mapping and modelling of optical properties from pulp to super calendered paper
- 2015
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Ingår i: Appita journal. - 1038-6807. ; 68:2, s. 128-138-
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Forskningsöversikt (refereegranskat)abstract
- During production of mechanical pulp based paper, the pulp darkenswithin the process which represents a significant cost for the mill. Amapping of the optical properties of the pulp was conducted along theprocess, from pulp mill to paper machine, at a mill producing supercalendered (SC) paper on three paper machines. The focus was to evaluateat which positions in the mill the discolouration occurs and also whichfraction of the pulp darkens the most.The fine fraction of the pulp darkened more than the long fibrefraction. Bleached pulp diluted with white water from the paper machinedarkened more during storage than pulp diluted with clear filtrate. Thewhite water contains a considerable amount of suspended solids, i.e.pulp fines and clay. There was a tendency for a shoulder in absorptionspectra of the pulp stored in white water from the paper machine in theregion 550 to 650 nm, both for fibres and for fines. This is in the sameregion where the added dyes have their absorption maxima and also somecomplexes between iron and some of the components among lignin and theextractives. Simulation of retention times of different fractions showedthat, although the main part of the fine material is retained in thepaper within a few hours, a small part might circulate for considerablylonger time.
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| 13. |
- Enberg, Sofia, et al.
(författare)
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Some causes of formation of colour during storage of hydrogen-peroxide bleached Norway spruce mechanical pulp
- 2014
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 29:2, s. 356-366
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Tidskriftsartikel (refereegranskat)abstract
- The discolouration of hydrogen-peroxide bleached Norway spruce mechanical pulp during storage in mill systems was studied and the contributions of process water, iron and dyes were evaluated over the visible spectrum. Washing of the pulp made it less sensitive to storage, possibly due to the removal of extractives, lignin-like substances, iron and pulp fines. Storage in white water gave extensive discolouration with a shoulder in the absorption spectrum at around 550-650 nm. Most of the colour was associated with pulp fines or filler but some colour was also found in smaller fractions and in the water phase. The addition of ferric ions increased the light absorption coefficient during storage, initially at short wavelengths and then over the whole spectrum, but could not explain the increased absorption at 550-650 nm and could not be the only cause of the darkening in the mill system. A cationic basic violet dye gave a shoulder in the absorption spectrum similar to that in the mill system, but the absorption in this area did not increase during storage. Model calculations indicate that ferric ions together with violet and red dyes could explain a major part, but not all, of the colour observed in the mill system after storage. The darkening not accounted for at longer wavelengths and around 550-650 nm is suggested to be related to fines and fillers including dissolved and colloidal substances associated with these particles.
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| 14. |
- Enberg, Sofia
(författare)
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Storage of Hydrogen Peroxide Bleached Mechanical Pulp : Reduction in Reflectance over the Visible Spectrum
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The objective of this thesis is to determine possible causes of the darkening of hydrogen peroxide bleached mechanical pulp over the visible spectrum and their relative contributions. It focuses on both process conditions and the composition of the pulp and the dilution water, including additions or losses of material along the process line from the bleach tower to the paper machine.A mapping of the optical properties of the pulp along the process showed that the fine fraction of the pulp darkened more than the long fibre fraction. Simulation of retention times of different fractions showed that the main part of the fine material is retained in the paper within a few hours, a small part might circulate for considerably longer time and may therefore be strongly coloured.Storage trials were mainly performed using a hydrogen peroxide bleached mechanical pulp intended for SC paper made of Norway spruce (Picea abies), sampled on one occasion and stored in a freezer. Unwashed or well-washed pulp was stored in distilled water or in different process waters. Some complementary trials were included, e.g. unbleached pulp.Time and temperature were the process variables that gave the strongest darkening of the pulp, as expected, both in a clean and a more process-like system, whereas pH only had an effect in the presence of process waters; the highest brightness stability was seen at a pH around 5.5–6.0.The darkening was due to an increase in the light absorption coefficient (k) beginning at short wavelengths, but after longer storage times the increase in kλ also became noticeable at longer wavelengths. The colour (CIE L*, a*, b*) of the pulp changed towards red and yellow, initially more towards red and then more towards yellow. These changes were clearly visible.Washing of the bleached pulp made it less sensitive to storage; possibly due to the removal of extractives, lignin-like substances, metals and pulp fines. This washing had little effect before storage and the amount of material removed was small.The pulp darkened more when stored in process waters compared to distilled water. Apart from fibres, most of the colour was associated with pulp fines or filler but some colour was also found in the dissolved and colloidal fractions. At an increased pulp consistency, the increase in k460 was smaller.Storage in white water from the paper machine gave extensive discolouration with a shoulder in the absorption spectrum around 550–650 nm, which increased with time. The addition of ferric ions increased the light absorption coefficient during storage, but could not explain the increased absorption at 550–650 nm nor could it be the only cause of the darkening in the mill system. A cationic basic violet dye gave a shoulder in the absorption spectrum similar to that of the mill system, but the absorption of the dye did not increase during storage. Model calculations indicate, but do not prove, that ferric ions together with violet and red dyes could have played a major, but not exclusive role in the colour observed in the mill system after storage. The darkening not accounted for, at longer wavelengths and around 550–650 nm, is suggested to be related to fines and fillers including dissolved and colloidal substances associated with these particles.A method to produce representative sheets for determination of optical properties of mechanical pulps was developed. The new method makes it possible to follow changes in light absorption and light scattering coefficients over the visible range of wavelengths. It is approximately six times faster than standard methods, reduces the risk of additional darkening of the sample and can be used with small pulp quantities.The deviation from the expected linear behaviour of the light scattering coefficient, s, at wavelengths corresponding to strong light absorption has been studied using the Kubelka-Munk model and the angular resolved DORT2002 radiative transfer solution method. The decrease in s could not be explained by errors introduced in the Kubelka-Munk modelling by anisotropic scattering.
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| 15. |
- Enberg, Sofia, et al.
(författare)
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The influence of process conditions during pulp storage on the optical properties of Norway spruce mechanical pulps
- 2013
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 28:2, s. 203-210
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this work was to study the influence of process conditions (time, pH, temperature and consistency) on the optical properties of mechanical pulps during storage in a clean system as a reference for further work. Laboratory storage trials were performed with unbleached and hydrogen-peroxide bleached well-washed Norway spruce pulps. In general, the pulp darkened during storage due to an increase in light absorption, especially at shorter wavelengths. After long storage times, the light absorption coefficient, k had increased also at longer wavelengths. No specific peaks were seen in Delta k-spectra. The increase in light absorption was most rapid initially, during the first four hours, for all pulps when stored at high temperature (80 degrees C), and then proceeded more slowly. The corresponding change in colour, measured as a* and b*, was shifted towards red and somewhat towards yellow, and over longer periods of storage, the shift towards yellow became greater. Time and temperature were found to have the largest impact. The effects were similar regardless of the starting pH (4.3-9.7) and pulp consistency (5%-25%). The hydrogen-peroxide bleached pulps were more sensitive to storage compared to the unbleached pulp at temperatures above 50 degrees C. At storage times of up to four hours, the unbleached pulp showed no loss of brightness at either of the storage temperatures. A slightly less bleached pulp darkened more than a highly bleached pulp at all wavelengths. The only difference measured between the two pulps was that the less bleached pulp had a higher content of iron. This higher iron content may be at least part of the reason for the more extensive darkening.
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| 16. |
- Enberg, Sofia, et al.
(författare)
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The influence of process waters on optical properties during storage of hydrogen-peroxide bleached Norway spruce mechanical pulp
- 2014
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 29:2, s. 344-355
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Tidskriftsartikel (refereegranskat)abstract
- To evaluate the causes behind the formation of colour in mill systems, the effect of different process waters on the optical properties of hydrogen-peroxide bleached Norway spruce mechanical pulp during storage was studied. The influence of process water type, temperature, time, pulp consistency and pH was evaluated over the visible range of wavelengths. The darkening was more pronounced when pulp was stored in process waters compared to in distilled water. Increased temperature and prolonged storage times increased the darkening as expected, whereas a higher storage consistency gave less darkening than a lower storage consistency (15% compared to 5%). The pH value that gave the lowest brightness reduction and a minimum in Delta k(460) was found to be 5.5-6.0. Storage of pulp in white water from the paper machine resulted in a broad shoulder in the k spectra indicating colour formation related to the particles in this water. Part of this shoulder in absorption spectra was related to added dyes, but the increase in absorption with time is likely to be caused by some other colour formation. The colour measured as a*, b* showed that the storage changed the colour of the pulp towards red and yellow, and initially more towards red.
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| 17. |
- Engstrand, Per, Professor, 1955-, et al.
(författare)
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Decrease in strengthalong a process line for SC paper
- 2019
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Ingår i: Fundamental Mechanical Pulp Research Seminar, FMPRS2019, Norrköping, SwedenArranged by Mid Sweden University in cooperatrion with Holmen AB, Valmet AB, AF AB and Treesearch..
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Konferensbidrag (refereegranskat)
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| 18. |
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| 19. |
- Fjellström, Helena, 1977-, et al.
(författare)
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A novel method for studying the photo-stabilising properties of coating layers
- 2006
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A new model system was developed which made it possible to study the reflectance and transmittance of thin coating layers (<10 g/m2) in a reproducible way, and to link this to the inhibition of the light-induced yellowing (Figure 1). The UV/VIS-screening properties of coatings of different coat weights containing common pigments such as kaolin, calcium carbonate (ground or precipitated) and titanium dioxide will be reported. The ability of a coating layer to protect a birch CTMP from light-induced discoloration will be exemplified using the evolved model system. An estimation of the contribution of different wavelength regions of the illuminating light to the photo-yellowing of various types of materials will also be shown. The developed method is a valuable tool for future photo-yellowing studies as well as for optimisation of the pigment coating formulation for various paper grades.
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| 20. |
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| 21. |
- Fjellström, Helena, et al.
(författare)
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Inhibition of light-induced brightness reversion of high-yield pulps : the UV-screening properties of coating layers containing kaolin or calcium carbonate pigments
- 2007
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 22:3, s. 350-355
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Tidskriftsartikel (refereegranskat)abstract
- A newly developed method making it possible to study the reflectance/transmittance of thin coating layers and to link this to the inhibition of the light-induced yellowing, was used to describe the photo-stabilising properties of different types of commercial kaolin and calcium carbonate pigments. A base paper produced from a hydrogen-peroxide-bleached birch chemithermomechanical pulp (CTMP) was used throughout the study.The transmittance of the coating layers in the UV-region (300-385 nm) was found to be very low (below 1.0% at coat weights < 5g/m2) for all of the tested pigments, it strongly depends on the coat weight especially for coat weights below 10 g/m2. The kaolin pigments examined were found to be better in inhibiting the brightness reversion compared to the calcium carbonate pigments, even though the differences between the pigment types were only a few brightness units. The coating layer was, however, able to conceal some of the colour formed through the light-induce brightness reversion. For example, a coating layer consisting of kaolin pigments (coat weight of 15.6 g/m2) could conceal about 30% of the discoloration of the CTMP base paper.
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| 22. |
- Fjellström, Helena
(författare)
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Inhibition of light-induced colour reversion of wood-containing papers by means of coating
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The main purpose of this thesis was to find ways to maintain a low level of light‐induceddiscolouration at an increased addition of mechanical and chemimechanical pulps in coated highqualityfine paper and magazine paper grades. Current technology allows the production of highyieldpulps such as thermomechanical and chemimechanical pulps with properties suitable formanufacturing high‐quality paper or paperboard with a low basis weight. Coating of woodcontainingpaper will probably be necessary for photo‐stability reasons if lignin‐containing pulps areto be used as the main fibre furnish in long‐life and high‐value products.In order to find the most suitable pulp for this purpose, light‐induced discolouration of a variety ofpaper samples from unbleached and bleached softwood and hardwood pulps was studied under bothaccelerated and long‐term ambient light‐induced ageing conditions. Hardwood high‐yield pulps,especially aspen pulps, were proven to be more photo‐stable compared to softwood pulps. Hardwoodpulps should therefore be the first choice for applications where a high permanence is desirable.Evaluating ageing characteristics using the CIELAB colour system showed that accelerated ageingconditions tend to mainly increase the b* value and decrease the L* value (i.e. yellow the pulp),whereas long‐term ambient ageing also increases the a* value, which makes the pulp more reddish.A new method for studying the influence of the UV‐screening properties of coating layers on abase paper was developed, and used to investigate the effect of pigment, pigment size distribution,binder and UV‐absorbing additives. The coat weight and pigment type were found to be the mostimportant factors for reducing the transmittance of UV‐radiation. Coating colours containing kaolinpigments had a lower UV‐transmittance than calcium carbonate pigments. Of the calcium carbonates,precipitated calcium carbonates were better than ground calcium carbonates and the difference wasgreater at higher coat weights. The particle size distribution should preferable be narrow. When thebest pigment (bleached kaolin) and the best binder (styrene butadiene latex) were combined withtitanium dioxide, the UV‐transmittance could be reduced by about 90% at a coat weight of ~10 g/m2.At a coat weight close to 20 g/m2, the transmittance was close to zero. This shows that it is possible tomore or less fully protect a double coated base paper from harmful UV‐radiation, when the coatinglayer has an optimum composition for that purpose. A prerequisite to reach so far is that the coatinglayer has an even coat weight.
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| 23. |
- Fjellström, Helena, et al.
(författare)
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Light-induced yellowing of mechanical and chemimechanical pulp sheets : influence of wood raw material, process and ageing method
- 2007
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 22:1, s. 117-123
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Tidskriftsartikel (refereegranskat)abstract
- The light-induced brightness reversion of different types of unbleached and bleached high-yield pulps was studied under both accelerated and long-term ambient light-induced ageing conditions. It was found that accelerated ageing conditions that mimic indoor daylight exposures overestimate the yellowing tendencies of hardwood high-yield pulps (especially aspen pulps) compared to long-term ambient aging with no indirect sunlight present. It was, however, possible to predict the yellowing characteristics of softwood high-yield pulps. The lignin content of the pulps was found to be strongly correlated with the degree of photo-yellowing in the case of long-term ambient light-induced ageing. The presence of small amounts of birch chemithermomechanical pulp (CTMP) in a fine paper furnish resulted in extensive light-induced discoloration. The extent of photo-yellowing was found to be nearly linearly related to the amount of birch CTMP in the paper.
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| 24. |
- Fjellström, Helena, et al.
(författare)
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The UV-screening properties of coating layers : The influence of pigments, binders and additives
- 2009
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Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 24:2, s. 206-212
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Tidskriftsartikel (refereegranskat)abstract
- The ability of coating colours to obstruct ultraviolet (UV) radiation in the 300-385 nm region was examined with the aim of finding the best photo-stabilising formulation to inhibit discoloration of high-yield pulps. The influence of pigment type, bleaching of the pigments, pigment size, pigment size distribution, type of binder and addition of U-V-absorbing compounds were examined using a newly developed method for studying the reflectance and transmittance properties of thin coating layers.The pigment type and coat weight was found to be the most important factors for reducing the transmittance of UV-radiation. Kaolin clays were more effective than calcium carbonate pigments and are therefore a better coating pigment for photostability reasons. Bleaching of the pigments, resulted in an overall minor decrease in transmittance for both kaolin and ground calcium carbonate (GCC) pigments, especially at low coat weights. Bleaching of the pigments changed the particle size distribution somewhat, which probably alters the structure in the coating layer. Precipitated calcium carbonate (PCC) pigments have a higher UV-screening potential compared to GCC pigments and should therefore be a better choice among the calcium carbonates. It was further concluded that a narrow pigment size distribution was beneficial for reducing the amount of transmitted UV-radiation that reaches the base paper. Styrene butadiene latex and polyvinylpyrrolidone were better in reducing the transmittance in the UV-region than polyvinyl alcohol.Adding a fluorescent whitening agent to a coating colour decreased the transmittance in the UV-region when the pigment was of the GCC type, and increased the transmittance when kaolin pigment was used. Addition of titanium dioxide (3 parts) to a coating colour containing kaolin pigment blocked about 90% of the UV-radiation at a coat weight of 10 g/m(2), which is a common coat weight for a single coated paper. Another possibility is to double coat to increase the coat weight, which turns the transmittance factor closed to zero.
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| 25. |
- Frederiksen, Thomas, et al.
(författare)
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Exploring the Tilt-Angle Dependence of Electron Tunneling across Molecular Junctions of Self-Assembled Alkanethiols
- 2009
-
Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 3:8, s. 2073-2080
-
Tidskriftsartikel (refereegranskat)abstract
- Electronic transport mechanisms in molecular junctions are investigated by a combination of first-principles calculations and current-voltage measurements of several well-characterized structures. We study self-assembled layers of alkanethiols grown on Au(111) and form tunnel junctions by contacting the molecular layers with the tip of a conductive force microscope. Measurements done under low-load conditions permit us to obtain reliable tilt-angle and molecular length dependencies of the low-bias conductance through the alkanethiol layers. The observed dependence on tilt-angle is stronger for the longer molecular chains. Our calculations confirm the observed trends and explain them as a result of two mechanisms, namely, a previously proposed intermolecular tunneling enhancement as well as a hitherto overlooked tilt-dependent molecular gate effect.
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| 26. |
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| 27. |
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| 28. |
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| 29. |
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| 30. |
- Frederiksen, T., et al.
(författare)
-
Theory of action spectroscopy for single-molecule reactions induced by vibrational excitations with STM
- 2014
-
Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 89:3, s. 035427-
-
Tidskriftsartikel (refereegranskat)abstract
- A theory of action spectroscopy, i.e., a reaction rate or yield as a function of bias voltage, is presented for single-molecule reactions induced by the inelastic tunneling current with a scanning tunneling microscope. A formula for the reaction yield is derived using the adsorbate resonance model, which provides a versatile tool to analyze vibrationally mediated reactions of single adsorbates on conductive surfaces. This allows us to determine the energy quantum of the excited vibrational mode, the effective broadening of the vibrational density of states (as described by Gaussian or Lorentzian functions), and a prefactor characterizing the elementary process behind the reaction. The underlying approximations are critically discussed. We point out that observation of reaction yields at both bias voltage polarities can provide additional insight into the adsorbate density of states near the Fermi level. As an example, we apply the theory to the case of flip motion of a hydroxyl dimer (OD)(2) on Cu(110) which was experimentally observed by Kumagai et al. [Phys. Rev. B 79, 035423 (2009)]. In combination with density functional theory calculations for the vibrational modes, the vibrational damping due to electron-hole pair generation, and the potential energy landscape for the flip motion, a detailed microscopic picture for the switching process is established. This picture reveals that the predominant mechanism is excitation of the OD stretch modes which couple anharmonically to the low-energy frustrated rotation mode.
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| 31. |
- Granbom, Marianne, et al.
(författare)
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Ageing in the right place–a prototype of a web-based housing counselling intervention for later life
- 2020
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Ingår i: Scandinavian Journal of Occupational Therapy. - : Informa UK Limited. - 1103-8128 .- 1651-2014. ; 27:4, s. 289-297
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Tidskriftsartikel (refereegranskat)abstract
- Background: Despite a strong desire among most older adults to age in place, there are few widely available services to support planning and preparing for one’s future housing needs. Objective: To develop a prototype of a web-based housing counselling intervention for use in later life, by employing a user-centred design. Material and Methods: As the first step in intervention development, we employed a development process based on research circle methodology. Nine older adults participated in three sessions. Findings from literature reviews, a meeting with a technology and design panel (n = 6) and interviews with representatives of nonprofit organizations, companies, and municipalities (n = 7) served as discussion points. Result: An on-paper prototype was derived, composed of the THINK, LEARN and ACT module reflecting different stages of the decision-making process. Each module addressed preferences, health, home and social and financial resources. Key design features and theoretical underpinnings were included. Conclusion and Significance: A user-centred design process can result in services that are aligned with older adults’ preferences for obtaining housing information. Services for planning and preparing future housing needs have the potential to increase older adults´ well-being at home as well as reduce costs for care and housing provision by the municipalities.
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| 32. |
- Gustafsson, Alexander, 1982-, et al.
(författare)
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Analysis of STM images with pure and CO-functionalized tips : A first-principles and experimental study
- 2017
-
Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 96:8
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Tidskriftsartikel (refereegranskat)abstract
- We describe a first-principles method to calculate scanning tunneling microscopy (STM) images, and compare the results to well-characterized experiments combining STM with atomic force microscopy (AFM). The theory is based on density functional theory with a localized basis set, where the wave functions in the vacuum gap are computed by propagating the localized-basis wave functions into the gap using a real-space grid. Constant-height STM images are computed using Bardeen's approximation method, including averaging over the reciprocal space. We consider copper adatoms and single CO molecules adsorbed on Cu(111), scanned with a single-atom copper tip with and without CO functionalization. The calculated images agree with state-of-the-art experiments, where the atomic structure of the tip apex is determined by AFM. The comparison further allows for detailed interpretation of the STM images.
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| 33. |
- Gustafsson, Alexander, 1982-
(författare)
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Modeling of non-equilibrium scanning probe microscopy
- 2015
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The work in this thesis is basically divided into two related but separate investigations.The first part treats simple chemical reactions of adsorbate molecules on metallic surfaces, induced by means of a scanning tunneling probe (STM). The investigation serves as a parameter free extension to existing theories. The theoretical framework is based on a combination of density functional theory (DFT) and non-equilibrium Green's functions (NEGF). Tunneling electrons that pass the adsorbate molecule are assumed to heat up the molecule, and excite vibrations that directly correspond to the reaction coordinate. The theory is demonstrated for an OD molecule adsorbed on a bridge site on a Cu(110) surface, and critically compared to the corresponding experimental results. Both reaction rates and pathways are deduced, opening up the understanding of energy transfer between different configurational geometries, and suggests a deeper insight, and ultimately a higher control of the behaviour of adsorbate molecules on surfaces.The second part describes a method to calculate STM images in the low bias regime in order to overcome the limitations of localized orbital DFT in the weak coupling limit, i.e., for large vacuum gaps between a tip and the adsorbate molecule. The theory is based on Bardeen's approach to tunneling, where the orbitals computed by DFT are used together with the single-particle Green's function formalism, to accurately describe the orbitals far away from the surface/tip. In particular, the theory successfully reproduces the experimentally well-observed characteristic dip in the tunneling current for a carbon monoxide (CO) molecule adsorbed on a Cu(111) surface. Constant height/current STM images provide direct comparisons to experiments, and from the developed method further insights into elastic tunneling are gained.
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| 34. |
- Gustafsson, Alexander, et al.
(författare)
-
Scanning tunneling microscopy current from localized basis orbital density functional theory
- 2016
-
Ingår i: Physical Review B. - 2469-9950 .- 2469-9969. ; 93:11
-
Tidskriftsartikel (refereegranskat)abstract
- We present a method capable of calculating elastic scanning tunneling microscopy (STM) currents from localized atomic orbital density functional theory (DFT). To overcome the poor accuracy of the localized orbital description of the wave functions far away from the atoms, we propagate the wave functions, using the total DFT potential. From the propagated wave functions, the Bardeen's perturbative approach provides the tunneling current. To illustrate the method we investigate carbon monoxide adsorbed on a Cu(111) surface and recover the depression/protrusion observed experimentally with normal/CO-functionalized STM tips. The theory furthermore allows us to discuss the significance of s- and p-wave tips.
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| 35. |
- Gustafsson, Alexander, 1982-, et al.
(författare)
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STM contrast of a CO dimer on a Cu(111) surface: a wave-function analysis
- 2017
-
Ingår i: Journal of Physics. - : Institute of Physics Publishing (IOPP). - 0953-8984 .- 1361-648X. ; 29:505301
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Tidskriftsartikel (refereegranskat)abstract
- We present a method used to intuitively interpret the scanning tunneling microscopy (STM) contrast by investigating individual wave functions originating from the substrate and tip side. We use localized basis orbital density functional theory, and propagate the wave functions into the vacuum region at a real-space grid, including averaging over the lateral reciprocal space. Optimization by means of the method of Lagrange multipliers is implemented to perform a unitary transformation of the wave functions in the middle of the vacuum region. The method enables (i) reduction of the number of contributing tip-substrate wave function combinations used in the corresponding transmission matrix, and (ii) to bundle up wave functions with similar symmetry in the lateral plane, so that (iii) an intuitive understanding of the STM contrast can be achieved. The theory is applied to a CO dimer adsorbed on a Cu(1 1 1) surface scanned by a single-atom Cu tip, whose STM image is discussed in detail by the outlined method.
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| 36. |
- Gustafsson, Alexander, 1982-
(författare)
-
Theoretical modeling of scanning tunneling microscopy
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The main body of this thesis describes how to calculate scanning tunneling microscopy (STM) images from first-principles methods. The theory is based on localized orbital density functional theory (DFT), whose limitations for large-vacuum STM models are resolved by propagating localized-basis wave functions close to the surface into the vacuum region in real space. A finite difference approximation is used to define the vacuum Hamiltonian, from which accurate vacuum wave functions are calculated using equations based on standard single-particle Green’s function techniques, and ultimately used to compute the conductance. By averaging over the lateral reciprocal space, the theory is compared to a series of high-quality experiments in the low- bias limit, concerning copper surfaces with adsorbed carbon monoxide (CO) species and adsorbate atoms, scanned by pure and CO-functionalized copper tips. The theory compares well to the experiments, and allows for further insights into the elastic tunneling regime.A second significant project in this thesis concerns first-principles calculations of a simple chemical reaction of a hydroxyl (oxygen-deuterium) monomer adsorbed on a copper surface. The reaction mechanism is provided by tunneling electrons that, via a finite electron-vibration coupling, trigger the deuterium atom to flip between two nearly identical configurational states along a frustrated rotational motion. The theory suggests that the reaction primarily occurs via nuclear tunneling for the deuterium atom through the estimated reaction barrier, and that over-barrier ladder climbing processes are unlikely.
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| 37. |
- Gustafsson, Alexander, et al.
(författare)
-
Theory of vibrationally assisted tunneling for hydroxyl monomer flipping on Cu(110)
- 2014
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 90:16, s. Article ID: 165413-
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Tidskriftsartikel (refereegranskat)abstract
- To describe vibrationally mediated configuration changes of adsorbates on surfaces we have developed a theory to calculate both reaction rates and pathways. The method uses the T-matrix to describe excitations of vibrational states by the electrons of the substrate, adsorbate, and tunneling electrons from a scanning tunneling probe. In addition to reaction rates, the theory also provides the reaction pathways by going beyond the harmonic approximation and using the full potential energy surface of the adsorbate which contains local minima corresponding to the adsorbates different configurations. To describe the theory, we reproduce the experimental results in [T. Kumagai et al., Phys. Rev. B 79, 035423 (2009)], where the hydrogen/deuterium atom of an adsorbed hydroxyl (OH/OD) exhibits back and forth flipping between two equivalent configurations on a Cu(110) surface at T = 6 K. We estimate the potential energy surface and the reaction barrier, similar to 160 meV, from DFT calculations. The calculated flipping processes arise from (i) at low bias, tunneling of the hydrogen through the barrier, (ii) intermediate bias, tunneling electrons excite the vibrations increasing the reaction rate although over the barrier processes are rare, and (iii) higher bias, overtone excitations increase the reaction rate further.
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| 38. |
- Hansson, Anders, et al.
(författare)
-
Effect of bending and vacancies on the conductance of carbon nanotubes
- 2000
-
Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 62:11, s. 7639-7644
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Tidskriftsartikel (refereegranskat)abstract
- Electron transport through nanotubes is studied theoretically using the Landauer formalism. The studies are carried out for finite metallic nanotubes that bridge two contacts pads. The current is observed to increase stepwise with the applied voltage. Each step corresponds to resonance tunneling including one single-particle eigenstate of the nanotube. Moderate bending of the nanotube results in a shift of the single-particle levels but the overall current remains essentially unaffected. For large bending, however, the pi electron system becomes more disturbed, which introduces backscattering and a marked decrease in the conductivity along the tube. A single carbon vacancy in the nanotube is shown to have very small effect on the conductivity in the center of the metallic band whereas, by increasing the defect concentration the conductivity decreases in the same way as for the strongly bent tubes.
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| 39. |
- Hayashi, M., et al.
(författare)
-
Lateral hopping of CO molecules on Pt(111) surface by femtosecond laser pulses
- 2009
-
Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 80:Article number: 245409
-
Tidskriftsartikel (refereegranskat)abstract
- Theory of heat transfer between adsorbate vibrational degrees of freedom and ultrafast laser heated hot electrons including vibrational intermode coupling is applied to calculate two-pulse correlation, laser fluence dependence and time dependence of lateral hopping of CO molecules from a step to terrace site on a stepped Pt (111) surface. The intermode coupling is a key ingredient to describe vibrational heating of the frustrated translation mode responsible for the CO hopping. The calculated results are in good agreement with the experimental results, especially if we scale down the experimentally determined absorbed fluence. It is found that CO hopping is induced by indirect heating of the FT mode by the FR mode with a strong frictional coupling to hot electrons.
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| 40. |
- Hellström, Mikael, et al.
(författare)
-
Styra meningsfullt med mål
- 2009
-
Ingår i: Ett smörgåsbord med ekonomistyrning och redovisning. - 9185113395 - 9789185113392 ; Nr 113, s. 207-229
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- I denna artikel belyses några kommunala ambitioner att styra med mål. En av frågorna vi ställer oss är varför vissa organisationer i den kommunala och landstingskommunala sektorn förefaller styras mer effektivt med mål än andra. Vad är det som gör att vissa offentliga organisationer vinner den ena utmärkelsen efter den andra avseende till exempel servicekvalité och styrning. Med vilken substans pratas det om att – X-kommun har lyckats göra något bra och på Y-sjukhus har de verkligen vänt på skutan. Är det några speciella beslut som tas? Vissa beslut förefaller leda till en styrning med mål som är bättre, mer effektiv än andra. Frågorna om mål och styrning är onekligen många. Syftet med denna artikel är att beskriva och analysera hur man kan styra effektivt med mål.
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| 41. |
- Hellström, Pia, 1960-, et al.
(författare)
-
A comparative study of enzymatic and Fenton pretreatment applied to a birch kraft pulp used for MFC production in a pilot scale high-pressure homogenizer
- 2016
-
Ingår i: TAPPI Journal. - : TAPPI Press. - 0734-1415. ; 15:6, s. 375-381
-
Tidskriftsartikel (refereegranskat)abstract
- Microfibrillated cellulose (MFC) was produced in pilot scale from a bleached birch (Betula verrucosa) kraft pulp that was pretreated with either Fenton's reagent or with a combined mechanical and enzymatic method used at the Centre Technique du Papier (CTP; Grenoble, France). The change in fiber fibrillation during the homogenization treatment was monitored by analyzing the fiber and the fines content, size fractionation, rheological properties and visualization by light-and scanning electron microscopy (SEM). The Fenton pretreatment resulted in MFC suspensions that contained a high amount of small sized elements. After five passes through the high-pressure homogenizer, the amount of particles smaller than 20 mu m was 37% for the Fenton pretreated MFC compared to 13% for the enzymatically (endoglucanase) pretreated MFC. Altogether, the Fenton pretreatment enabled preparation of MFC with a higher degree of fibrillation after the same number of passes through the high-pressure homogenizer. Another option is to produce MFC of the same amount of fibrillation as after an enzymatic stage, but at significantly lower energy consumption.
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| 42. |
- Hellström, Pia, 1960-, et al.
(författare)
-
Fenton pre-treated microfibrillated cellulose evaluated as a strength enhancer in the middle ply of paperboard
- 2014
-
Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 29:4, s. 732-740
-
Tidskriftsartikel (refereegranskat)abstract
- Microfibrillated celluloses (MFCs), produced by various pre-treatments of a fully bleached birch kraft pulp, were evaluated as strength enhancers in test sheets representing the middle ply of paperboard. The furnish consisted of hydrogen peroxide bleached high temperature spruce chemithermomechanical pulp (HT-CTMP), MFC and a retention system containing cationic starch and an anionic silica sol. The MFC was prepared via a mechanical treatment in a colloid mill after pretreatment with Fenton's reagent, monocomponent endoglucanase or acidic hydrogen peroxide. Addition of 5% MFC, produced with Fenton pre-treatment, resulted in improved HT-CTMP properties with respect to increased tensile index (similar to 35%), z-directional strength (similar to 50%), tensile stiffness index (similar to 25%) compared to HT-CTMP test sheets prepared without MFC addition. The strength improvement was linearly correlated to the density of the tests sheet, to the surface area (BET) and to the surface charge of the enzymatic or chemically pre-treated MFCs.
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| 43. |
- Hellström, Pia, 1960-
(författare)
-
Fenton Pre-treatment of a Birch Kraft Pulp for MFC preparation
- 2015
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The potential to use acidic hydrogen peroxide in the presence of ferrous ions (Fenton’s reagent) as a pre-treatment when producing microfibrillar cellulose (MFC) from a fully bleached birch (Betula verucosa) kraft pulp was investigated and the properties of the produced MFC was compared to the properties of a MFC produced with enzymatic pre-treatment with a monocomponent endoglucanase (FiberCare® R). The mechanical treatment to MFC was performed in a laboratory colloid mill or in a pilot high-pressure homogeniser and the pre-treated pulps as well as the produced MFCs were chemically and morphologically characterised. Additionally, the MFCs produced in the colloid mill were evaluated as strength enhancers in test sheets representing the middle ply of paperboard.From the chemical characterisation, it was concluded that the Fenton pre-treatment caused a decrease in the degree of polymerisation (DP) and an increase in both carboxyl- and carbonyl groups. The increase in carbonyl groups could not be explained by the formation of new reducing end groups due to depolymerisation which indicates that carbonyl groups are introduced along the cellulose chain. The enzymatic pre-treatment as performed in this study caused less impact on the cellulosic material, i.e. resulted in a pulp with a higher DP and a much lower amount of carbonyl- and carboxylic groups compared with the Fenton pre-treated pulps. In the subsequent mechanical treatment in a colloid mill, the Fenton pre-treated pulps were easier to process mechanically i.e. reached a higher specific surface area and a higher surface charge at a given mechanical treatment time compared to enzymatic pre-treated pulps and pulps not subjected to any pre-treatment. These findings were confirmed when MFCs were produced by homogenisation at high pressure in multiple passes; the birch kraft pulp was either pre-treated with Fenton’s reagent or the combined mechanic and enzymatic pre-treatment methodology used at the Centre Technique du Papier (CTP, France). By size fractionation, rheological measurements and scanning electron microscopy, it was revealed that Fenton pre-treatment resulted in MFC suspension containing a significantly higher proportion of small sized material (< 0.2 mm).When the MFCs were evaluated as strength enhancers in test sheets produced from a furnish consisting of a spruce (Picea abies) chemithermomechanical pulp, MFC and a retention system containing cationic starch and an anionic silica sol, Fenton pre-treated MFCs increased the strength properties more than the enzymatic pre-treated MFCs. Addition of 5 wt% Fenton pre-treated MFC resulted in an increase in z-directional strength of about 50%, an increase in tensile stiffness index of about 25% and an increase in tensile index of 35% compared to test sheets prepared without MFC addition.
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| 44. |
- Hellström, Pia, et al.
(författare)
-
The effect of Fenton chemistry on the production of microfibrillated cellulose - characterization and paper board application
- 2013
-
Konferensbidrag (refereegranskat)abstract
- A fully bleached birch (Betula verucosa) sulphate pulp was treated with acidic hydrogen peroxide in the presence of ferrous iron (i.e. Fenton's reagent) and thereafter treated mechanically in a colloid mill to produce microfibrillated cellulose (MFC). The produced MFCs were chemically and morphologically characterized and compared with MFCs produced with enzymatic (monocomponent endoglucanase) pre-treatment (Figure 1). As a reference MFC produced with only acid pre-treatment was also included in the study.The Fenton pre-treatment increased the total charge of the fibres, decreased the viscosity and introduced new carbonyl groups. Addition of 10 and 50 kg/t hydrogen peroxide resulted in a yield loss of 2 and 4%, respectively. The enzymatic hydrolysis did not substantially change the total charge or the carbonyl group content of the pulp and did not release any organic material. The Fenton pre-treated pulps were easier to process mechanically, i.e. they reached a higher specific surface (BET) area and thereby a higher surface charge at a given mechanical treatment time, indicating a potential to reduce the energy demand in the final mechanical processing stage. The Fenton pre-treatment produced microfibrillated cellulose that in a water suspension (0.5% consistency) was stable with respect to sedimentation for at least eight weeks (Figure 2). Further, the Fenton pre-treatment gave a MFC product that contained a higher amount of small well fibrillated particles, as indicated by fractionation and scanning electron microscopy, compared with the enzymatic and acid pre-treatment methods studied.
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| 45. |
- Hellström, Pia, 1960-, et al.
(författare)
-
The effect of Fenton chemistry on the properties of microfibrillated cellulose
- 2014
-
Ingår i: Cellulose. - : Springer. - 0969-0239 .- 1572-882X. ; 21:3, s. 1489-1503
-
Tidskriftsartikel (refereegranskat)abstract
- A fully bleached birch kraft pulp was treated with acidic hydrogen peroxide in the presence of ferrous ions (Fenton's reagent) and thereafter treated mechanically in a colloid mill to produce a product containing microfibrillated cellulose (MFC). The produced MFC products were chemically and morphologically characterized and compared with MFC products produced without pretreatment as well as with enzymatic hydrolysis. Fenton treatment resulted in an increase in total charge and number of carbonyl groups while the intrinsic viscosity decreased. The Fenton treated pulps were easier to process mechanically i.e. they reached a higher specific surface area at a given mechanical treatment time and the MFC produced had a stable water-fibre suspension for at least 8 weeks compared to enzymatic pretreated pulps and pulps not subjected to any pretreatment.
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| 46. |
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| 47. |
- Hjelmblom, Magnus, PhD, 1973-, et al.
(författare)
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Towards Automation of the Swedish Property Formation Process : A Structural and Logical Analysis of Property Subdivision
- 2019
-
Ingår i: Nordic Journal of Surveying and Real Estate Research. - : The Finnish Society of Built Environment Research. - 1459-5877 .- 2341-6599. ; 14:1, s. 29-63
-
Tidskriftsartikel (refereegranskat)abstract
- The ongoing digitalization of public administration and increasedautomation of legal decision-making bears promise to benefit citizens,businesses and other stakeholders through simpler and more efficient civilprocesses, and thus has great impact on the urban planning and buildingprocess. However, automation of decision-making that is directed orconstrained by normative systems such as laws, regulations and policies,requires a detailed and accurate representation of these concepts andtheir constituent parts, and the domain to which they are applied. Thispaper combines two perspectives on formalisation and classification oflegal relations within the urban planning and building domain. In a crossdisciplinaryfashion, the paper analyses and describes a small part of thisdomain at a higher level of abstraction and formalization using two differentanalysis instruments. Using these tools, we perform structural and conceptualas well as logical analyses of two specific snapshots of a fictitious propertysubdivision case in Sweden, focusing on the legal relations between differententities and parties involved in the specific situations. The structural analysisuses the Land Administration Domain Model ISO 19152:2012 standardformalism, and the logical analysis is based on the notion of atomic types oflegal relations. The paper discusses some of the strengths and weaknesses ofthe two tools regarding the formal representation of rights, restrictions andresponsibilities of different parties in the land administration domain, as wellas how the tools relate to each other and how they can be aligned. This papertakes one step towards a deeper understanding of the domain, and identifyareas for future research that may provide better conditions for efficient andtransparent use of geospatial information, and automation of the propertysubdivision process and other related civil processes.
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| 48. |
- Hossein Khademi, S. M., et al.
(författare)
-
Genomic and phenotypic evolution of achromobacter xylosoxidans during chronic airway infections of patients with cystic fibrosis
- 2021
-
Ingår i: mSystems. - 2379-5077. ; 6:3
-
Tidskriftsartikel (refereegranskat)abstract
- Bacterial pathogens evolve during chronic colonization of the human host by selection for pathoadaptive mutations. One of the emerging and understudied bacterial species causing chronic airway infections in patients with cystic fibrosis (CF) is Achromobacter xylosoxidans. It can establish chronic infections in patients with CF, but the genetic and phenotypic changes associated with adaptation during these infections are not completely understood. In this study, we analyzed the wholegenome sequences of 55 clinical A. xylosoxidans isolates longitudinally collected from the sputum of 6 patients with CF. Four genes encoding regulatory proteins and two intergenic regions showed convergent evolution, likely driven by positive selection for pathoadaptive mutations, across the different clones of A. xylosoxidans. Most of the evolved isolates had lower swimming motility and were resistant to multiple classes of antibiotics, while fewer of the evolved isolates had slower growth or higher biofilm production than the first isolates. Using a genome-wide association study method, we identified several putative genetic determinants of biofilm formation, motility and b-lactam resistance in this pathogen. With respect to antibiotic resistance, we discovered that a combination of mutations in pathoadaptive genes (phoQ and bigR) and two other genes encoding regulatory proteins (spoT and cpxA) were associated with increased resistance to meropenem and ceftazidime. Altogether, our results suggest that genetic changes within regulatory loci facilitate within-host adaptation of A. xylosoxidans and the emergence of adaptive phenotypes, such as antibiotic resistance or biofilm formation. IMPORTANCE A thorough understanding of bacterial pathogen adaptation is essential for the treatment of chronic bacterial infections. One unique challenge in the analysis and interpretation of genomics data is identifying the functional impact of mutations accumulated in the bacterial genome during colonization in the human host. Here, we investigated the genomic and phenotypic evolution of A. xylosoxidans in chronic airway infections of patients with CF and identified several mutations associated with the phenotypic evolution of this pathogen using genome-wide associations. Identification of phenotypes under positive selection and the associated mutations can enlighten the adaptive processes of this emerging pathogen in human infections and pave the way for novel therapeutic interventions.
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| 49. |
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| 50. |
- Karlsson, Anette, et al.
(författare)
-
Determining optical properties of mechanical pulps : Sheetmaking procedure and investigation of different ways to evaluate light absorption
- 2012
-
Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 27:3, s. 531-541
-
Tidskriftsartikel (refereegranskat)abstract
- A method to produce representative sheets for determination of optical properties of mechanical pulps has been developed. It reduces the risk of contamination and discoloration and can be used with small pulp quantities. The deviation from the expected linear behaviour of the light scattering coefficient, s, at wavelengths corresponding to strong light absorption, has been studied using the Kubelka-Munk model and the angular resolved DORT2002 radiative transfer solution method. This decrease in s could not be explained by errors introduced in the Kubelka-Munk modelling by anisotropic scattering. Linear extrapolation of s can therefore not be justified as a way to obtain a more correct light absorption coefficient, k. For thepulps studied, the decrease in s at short wavelengths had little effect on k at 457 nm.
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