| 1. |
- Boström, Ida Maria, et al.
(författare)
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CTG18.1 expansion in transcription factor 4 (TCF4) in corneal graft failure : preliminary study
- 2024
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Ingår i: Cell and Tissue Banking. - : Springer Science+Business Media B.V.. - 1389-9333 .- 1573-6814. ; 25, s. 613-618
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Tidskriftsartikel (refereegranskat)abstract
- Fuchs endothelial corneal dystrophy (FECD) is caused by a corneal endothelial cell loss, leading to corneal edema and visual impairment. The most significant genetic risk factor for FECD is an expansion of the CTG18.1 locus in transcription factor 4 (TCF4). The current treatment for severe FECD is corneal transplantation, with Descemet stripping automated keratoplasty (DSAEK) as a common surgical method. Although successful in most cases, the risk for transplant failure due to diverse causes must be considered. In this study, we investigated if presence of TCF4 CTG18.1 expansion with more than 31 (n ≥ 31) repeats in donated corneal grafts could be a reason for corneal transplant failure after DSAEK. For this, nine consecutively failed DSAEK corneal grafts were genotyped for CTG18.1 repeat length. One-sided Mann–Whitney U test was performed to evaluate if failed DSAEK corneal grafts had longer CTG18.1 repeats than healthy controls from the same population. All failed corneal grafts had CTG18.1 n ≤ 27 with a median of 18 (IQR 8.0) repeats for the longest allele. There was no statistical difference in CTG18.1 repeat lengths between failed corneal grafts and the geographically matched healthy control group. In conclusion, none of the nine failed corneal grafts in our material had CTG18.1 repeat lengths ≥ 31, a cut-off known to have a biological relevance in FECD. Thus, our results suggest that the assessment of donors and inspection of the corneal tissue before the decision for procurement is sufficient, in terms of recognizing FECD in the donor.
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| 2. |
- Fagerström, Jonathan, et al.
(författare)
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Influence of peat ash composition on particle emissions and slag formation in biomass grate co-combustion
- 2014
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 28:5, s. 3403-3411
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Tidskriftsartikel (refereegranskat)abstract
- Co-combustion by fuel blending of peat and biomass has shown positive effects on operational problems. However, peat ash compositions vary considerably, and this has been shown to affect the potential for operational problems in different fuel-blending situations. The present work used three different peat types with the objective to elucidate how the variation in peat ash composition influences both particle emissions and slag formation during co-combustion with three different biomasses in a small-scale pellet boiler. Estimations of potassium release and slag formation were performed and discussed in relation to fuel composition in the (K2O + Na2O)–(CaO + MgO)–(SiO2) system. All tested peat types reduced the fine particle emissions by capturing potassium into the bottom ash as one or several of the following forms: slag, sulfates, chlorides, and alumina silicates. However, there were considerable differences between the peat types, presumably depending upon both their content and mineral composition of silicon, calcium, aluminum, and sulfur. Some general important and beneficial properties of peat type in co-combustion situations with biomass are defined here, but the specific blending proportion of peat should be decided on an individual basis for each scenario based on the relative contents in the fuel mixture of the most relevant ash-forming elements.
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| 3. |
- Fagerström, Jonathan, et al.
(författare)
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Reduction of fine particle- and deposit forming alkali by co-combustion of peat with wheat straw and forest residues
- 2010
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Ingår i: Proceedings of the International Conference on Impact of Fuel Quality on Power production and the Environment..
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Combustion of ash rich biomass fuels like forest residues and wheat straw often cause severe fouling/deposits and high emissions of PM1, mainly related to alkali transformation. Due to technical and air pollution aspects, primary process/fuel related measures for reduction of volatilized alkali could therefore be of importance. Peat has been used extensively in e g Sweden and Finland since the early 80th due to its positive ash chemical effects. Earlier research with co-combustion of peat and biomass has mostly been focused on fluidized bed boilers and aspects of bed agglomeration and deposits/corrosion. It has also been shown that the content and form of ash forming elements in different peats can vary significantly. The objective with this work was to determine the potential reduction of fine particle- and deposit forming alkali during co-combustion of forest residue and wheat straw with four different peat types in a small scale (15 kW) grate fired pellet boiler. The results showed that significant reduction of fine particle- and deposit forming alkali is possible, either simply by "dilution" of K content (e.g for wheat straw) or by "capturing" of K to bottom ash/slag (e.g. for forest residues), most probably caused by reaction of K vapour from the biomass with reactive Si or clay minerals from the peat. The alkali reduction potential for different biomass fuels and peat mixtures is dicussed in relation to the slagging tendencies and general ash transformation processes
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| 4. |
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| 5. |
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| 6. |
- Jönsson, K. Ingemar, et al.
(författare)
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Environmental compensation as a policy tool in Swedish municipal planning
- 2019
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In the struggle to reach the national environmental policy objectives, environmental compensation has emerged as a possible policy tool that may contribute to achieving the objectives. In Sweden, environmental compensation is legally mandated mainly in cases of exploitation within Natura 2000 areas and nature reserves, which is handled through the Swedish Environmental Code. In contrast, regulatory support is weak when it comes to compensation for impacts arising from municipal development (e.g., housing, schools, hospitals, local roads, etc), even though detailed development planning is required through the Planning and Building Act. Despite this, some municipalities have voluntarily mainstreamed environmental compensation into their planning processes. In the research project ”MuniComp” (2018-2020) we investigate the more progressive use of environmental compensation in planning in two Southern Swedish municipalities, Lomma and Helsingborg (in the province of Skåne). We analyze the models and processes of compensation used, and planning cases where compensation have been applied, in terms of general aspects and criteria for environmental compensation and in light of the constraints of the Swedish legislative context. In the presentation, the compensation models and some of the results from the compensation cases will be presented.
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| 7. |
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| 8. |
- Nyström, Ida-Linn, et al.
(författare)
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Effect of peat addition to woody biomass pellets on slagging characteristics during combustion in residential pellet burners
- 2009
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Ingår i: From research to industry and markets. - Florence : ETA - Renewable Energies. ; , s. 1400-1405
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Konferensbidrag (refereegranskat)abstract
- Upgraded biofuels as pellets, briquettes and powder are today commonly used in small as well as large scale appliances. In order to cover a great fuel demand new materials as bark, whole tree assortments and peat are introduced. These materials have higher ash content why they are potentially more problematic compared with stem wood. Ash related problems in the combustion device, e.g. fouling, slagging and corrosion may occur from the incombustible leftover i.e. the fuel ash. The objective of the present work was to determine the effect on slagging characteristics when co-pelletizing peat into woody biomass. In this project woody biomass (pine and spruce 50/50) has been co-pelletized with three different mixtures (low, medium and high) of peat; peat A with high ash and high Si content and peat B with low ash and a relatively high Ca/Si content. There were totally 6 mixed assortments in which softwood sawdust and energy wood each represented the biomass in 3 samples respectively. The experiments were carried out in a commercial underfed pellet burner (20 kW) installed in a reference boiler. X-ray diffraction (XRD) was used to characterize the phase composition and scanning electron microscopy combined with energy dispersive X-ray analysis (SEM-EDS) were utilized in order to characterize the elemental distribution and morphology of the collected slag deposits and bottom ashe. The slagging tendency showed an obvious increment when adding peat into the woody biomasses. Especially the ash- and relatively Ca-poor sawdust fuel was generally more sensitive for the different peat assortments. Co-firing of peat A (high ash- and Si content) resulted in the most severe slagging tendency, where four out of six experiments led to a total shut down of the burner due to the slagging. The slagging tendency was significantly lower when adding peat B (ash poor and relatively high (Ca/Si ratio) into the woody biomass fuels. A significant increment of the Si, Al and Fe content and a significant decrement of the Ca content could be seen when increasing the mixing content of peat A in both woody biomasses. The slag from the peat B mixtures had a slightly higher Ca content compared with the Si content and a clearly higher Ca content compared with the peat A mixtures. When introducing the relatively silicon rich Peat A to the woody biomasses the slagging tendency increased because high temperature melting Ca-Mg oxides reacts to form more low temperature melting Ca-Al-K silicates. In the case of the more ash poor peat B, with relatively high Ca/Si ratio, there were still Ca-Mg oxides left in the bottom ash i.e. a less amount of sticky low temperature melting Ca-Al-K silicates were formed.
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| 9. |
- Näzelius, Ida-Linn, et al.
(författare)
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Fuel Indices for Estimation of Slagging of Phosphorus-Poor Biomass in Fixed Bed Combustion
- 2017
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 31:1, s. 904-915
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Tidskriftsartikel (refereegranskat)abstract
- The market for solid biofuels will grow rapidly during the coming years and there will be a great demand for raw materials. This will force the existing fuel base to also cover wooden materials of lower qualities as well as agricultural raw materials and residues, which often show unfavorable ash melting temperatures. This may lead to combustion related problems. Thus, for the utilization of lower quality fuels, it is important to be able to predict potential fuel ash related problems such as slagging. In light of this, the first objective of the present paper was to evaluate the applicability of previously defined indices for slagging of biomass fuels (phosphorus-poor) in fixed bed combustion. The evaluation showed that none of the previously suggested indices in the literature are suitable for qualitative (nor quantitative) prediction of slagging during fixed bed combustion of P-poor biomass fuels. Hence, a second objective was to develop improved novel fuel indices that can be applied to estimate the slagging of phosphorus-poor biomass in fixed bed combustion. The novel fuel indices give a qualitative prediction of the slagging tendency in biomass fixed bed combustion but still needs additional work to further extend the compositional range as well as to fine-tune the indices’ boundaries.
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| 10. |
- Näzelius, Ida-Linn, et al.
(författare)
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Influence of peat addition to woody biomass pellets on slagging characteristics during combustion
- 2013
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 27:7, s. 3997-4006
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Tidskriftsartikel (refereegranskat)abstract
- Upgraded biofuels such as pellets, briquettes, and powder are today commonly used in small as well as large scale appliances. In order to cover an increasing fuel demand new materials such as bark, whole tree assortments, and peat are introduced. These materials have higher ash content which is why they are potentially more problematic compared with stem wood. In general, few studies can be found regarding cocombustion of peat and biomass and in particular where the slagging tendencies are discussed. The overall objective of this study was therefore to determine the influence of peat addition to woody biomass pellets on slagging characteristics. Two different peat assortments (peat A and B) were copelletized separately in four different dry matter levels (0-5-15-30 wt %) into stem wood and energy wood, respectively. Peat A was a traditional Scandinavian fuel peat, with a high ash and Si content (carex), and peat B had a low ash content and relatively high Ca/Si ratio (sphagnum) chosen for its special characteristics. The produced pellets were combusted in a commercial underfed pellet burner (15 kW) installed in a reference boiler. The collected deposits (bottom ash and slag) from the combustion experiments were chemically characterized by scanning electron microscopy (SEM) combined with energy-dispersive X-ray analysis (EDS) and X-ray diffraction (XRD) regarding the elemental distribution and morphology and phase composition, respectively. In addition, the bottom ashes were characterized according to inductively coupled plasma atomic emission spectroscopy (ICP-AES). To interpret the experimental findings chemical equilibrium model calculations were performed. The slagging tendency increased when adding peat into the woody biomasses. Especially sawdust with its relatively low ash and Ca content was generally more sensitive for the different peat assortments. Cofiring with the relatively Si and ash rich peat A resulted in the most severe slagging tendency. A significant increment of the Si, Al, and Fe content and a significant decrement of the Ca content in the slag could be seen when increasing the content of peat A in both woody biomasses. The slagging tendency increased when adding peat A because high temperature melting Ca-Mg oxides react to form more low temperature melting Ca/Mg-Al-K silicates. The slagging tendency was significantly lower when adding the more ash poor peat B, with relatively high Ca/Si ratio, into the woody biomass fuels compared with the peat A mixtures. The slag from the peat B mixings had a slightly higher Ca content compared with the Si content and a clearly higher content of Ca compared with the peat A mixtures. There were still Ca-Mg oxides left in the bottom ash i.e. a less amount of sticky low temperature melting K-silicate rich melt was formed when peat B was added to the woody biomasses.
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