| 1. |
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| 2. |
- Bunse, Carina, et al.
(författare)
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Spatio-Temporal Interdependence of Bacteria and Phytoplankton during a Baltic Sea Spring Bloom
- 2016
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Ingår i: Frontiers in Microbiology. - : Frontiers Media S.A.. - 1664-302X. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- In temperate systems, phytoplankton spring blooms deplete inorganic nutrients and are major sources of organic matter for the microbial loop. In response to phytoplankton exudates and environmental factors, heterotrophic microbial communities are highly dynamic and change their abundance and composition both on spatial and temporal scales. Yet, most of our understanding about these processes comes from laboratory model organism studies, mesocosm experiments or single temporal transects. Spatial -temporal studies examining interactions of phytoplankton blooms and bacterioplankton community composition and function, though being highly informative, are scarce. In this study, pelagic microbial community dynamics (bacteria and phytoplankton) and environmental variables were monitored during a spring bloom across the Baltic Proper (two cruises between North Germany to Gulf of Finland). To test to what extent bacterioplankton community composition relates to the spring bloom, we used next generation amplicon sequencing of the 16S rRNA gene, phytoplankton diversity analysis based on microscopy counts and population genotyping of the dominating diatom Skeletonema rnarinoi. Several phytoplankton bloom related and environmental variables were identified to influence bacterial community composition. Members of Bacteroidetes and Alphaproteobacteria dominated the bacterial community composition but the bacterial groups showed no apparent correlation with direct bloom related variables. The less abundant bacterial phyla Actinobacteria, Planctomycetes, and Verrucomicrobia, on the other hand, were strongly associated with phytoplankton biomass, diatom:dinoflagellate ratio, and colored dissolved organic matter (cDOM). Many bacterial operational taxonomic units (OTUs) showed high niche specificities. For example, particular Bacteroidetes OTUs were associated with two distinct genetic clusters of S. marinoi. Our study revealed the complexity of interactions of bacterial taxa with inter- and intraspecific genetic variation in phytoplankton. Overall, our findings imply that biotic and abiotic factors during spring bloom influence bacterial community dynamics in a hierarchical manner.
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| 3. |
- Clark, Eric, et al.
(författare)
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Island gentrification and space wars
- 2007
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Ingår i: A world of islands. - 9789993286103 ; , s. 483-512
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 4. |
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| 5. |
- Fromell, Karin, et al.
(författare)
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The effect of airborne Palladium nanoparticles on human lung cells, endothelium and blood-A combinatory approach using three in vitro models
- 2023
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Ingår i: Toxicology in Vitro. - : Elsevier. - 0887-2333 .- 1879-3177. ; 89
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Tidskriftsartikel (refereegranskat)abstract
- A better understanding of the mechanisms behind adverse health effects caused by airborne fine particles and nanoparticles (NP) is essential to improve risk assessment and identification the most critical particle exposures. While the use of automobile catalytic converters is decreasing the exhausts of harmful gases, concentrations of fine airborne particles and nanoparticles (NPs) from catalytic metals such as Palladium (Pd) are reaching their upper safe level. Here we used a combinatory approach with three in vitro model systems to study the toxicity of Pd particles, to infer their potential effects on human health upon inhalation. The three model systems are 1) a lung system with human lung cells (ALI), 2) an endothelial cell system and 3) a human whole blood loop system. All three model systems were exposed to the exact same type of Pd NPs. The ALI lung cell exposure system showed a clear reduction in cell growth from 24 h onwards and the effect persisted over a longer period of time. In the endothelial cell model, Pd NPs induced apoptosis, but not to the same extent as the most aggressive types of NPs such as TiO2. Similarly, Pd triggered clear coagulation and contact system activation but not as forcefully as the highly thrombogenic TiO2 NPs. In summary, we show that our 3-step in vitro model of the human lung and surrounding vessels can be a useful tool for studying pathological events triggered by airborne fine particles and NPs.
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| 6. |
- Godhe, Anna, 1967, et al.
(författare)
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Physical barriers and environmental gradients cause spatial and temporal genetic differentiation of an extensive algal bloom
- 2016
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Ingår i: Journal of Biogeography. - : John Wiley & Sons. - 0305-0270 .- 1365-2699. ; 43:6, s. 1130-1142
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To test if a phytoplankton bloom is panmictic, or whether geographical and environmental factors cause spatial and temporal genetic structure.Location: Baltic Sea.Method: During four cruises, we isolated clonal strains of the diatom Skeletonema marinoifrom 9 to 10 stations along a 1132 km transect and analysed the genetic structure using eight microsatellites. Using F-statistics and Bayesian clustering analysis we determined if samples were significantly differentiated. A seascape approach was applied to examine correlations between gene flow and oceanographic connectivity, and combined partial Mantel test and RDA based variation partitioning to investigate associations with environmental gradients.Results: The bloom was initiated during the second half of March in the southern and the northern- parts of the transect, and later propagated offshore. By mid-April the bloom declined in the south, whereas high phytoplankton biomass was recorded northward. We found two significantly differentiated populations along the transect. Genotypes were significantly isolated by distance and by the south–north salinity gradient, which illustrated that the effects of distance and environment were confounded. The gene flow among the sampled stations was significantly correlated with oceanographic connectivity. The depletion of silica during the progression of the bloom was related to a temporal population genetic shift.Main conclusions: A phytoplankton bloom may propagate as a continuous cascade and yet be genetically structured over both spatial and temporal scales. The Baltic Sea spring bloom displayed strong spatial structure driven by oceanographic connectivity and geographical distance, which was enhanced by the pronounced salinity gradient. Temporal transition of conditions important for growth may induce genetic shifts and different phenotypic strategies, which serve to maintain the bloom over longer periods.
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| 7. |
- Hansson, Jeanette, 1972, et al.
(författare)
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Antibiotics as First-line Therapy for Acute Appendicitis: Evidence for a Change in Clinical Practice.
- 2012
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Ingår i: World journal of surgery. - : Springer Science and Business Media LLC. - 1432-2323 .- 0364-2313. ; 36:9, s. 2028-36
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Tidskriftsartikel (refereegranskat)abstract
- Randomized studies have indicated that acute appendicitis may be treated by antibiotics without the need of surgery. However, concerns have been raised about selection bias of patients in such studies. Therefore, the present study was aimed to validate previous findings in randomized studies by a full-scale population-based application.
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| 8. |
- Hedin, Karin, et al.
(författare)
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Neoliberalization of housing in Sweden : gentrification, filtering, and social polarization
- 2012
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Ingår i: Annals of the Association of American Geographers. - : Informa UK Limited. - 0004-5608 .- 1467-8306. ; 102:2, s. 443-463
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Tidskriftsartikel (refereegranskat)abstract
- During the last twenty-five years, housing policy in Sweden has radically changed. Once forming a pillar of the comprehensive welfare system, abbreviated the “Swedish model,” neoliberal housing politics have established market-governed housing provision with a minimum of state engagement. This shift has had consequences on the social geography of housing conditions. The research reported here analyzes social geographic change in Sweden's three largest cities—Stockholm, Gothenburg, and Malmö—between 1986 and 2001, relating observed patterns of gentrification and filtering to cycles of accumulation and to neoliberalization of housing policies. First, we outline the neoliberalization of Swedish housing policies. We then present an empirical analysis of gentrification and filtering in the three cities, spanning two boom periods (1986–1991, 1996–2001) and a bust period (1991–1996). The data reveal social geographic polarization manifested in the growth of supergentrification and low-income filtering. The analysis also introduces the concept of ordinary gentrification, supporting the move in gentrification research toward a broad generic conception of the process. Political reforms after 2001 are summarized and we argue that these underlie the continued increase in inequality and that the social geographic polarization mapped between 1986 and 2001 has probably intensified during this decade.
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| 9. |
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| 10. |
- Liu, Bojing, et al.
(författare)
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β2-adrenoreceptor agonists, montelukast, and Parkinson's disease risk
- 2023
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Ingår i: Annals of Neurology. - : John Wiley & Sons. - 0364-5134 .- 1531-8249. ; 93:5, s. 1023-1028
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Tidskriftsartikel (refereegranskat)abstract
- Objective: This study was undertaken to examine the association between montelukast use, beta 2-adrenoreceptor (beta 2AR) agonist use, and later Parkinson disease (PD).Methods: We ascertained use of beta 2AR agonists (430,885 individuals) and montelukast (23,315 individuals) from July 1, 2005 to June 30, 2007, and followed 5,186,886 PD-free individuals from July 1, 2007 to December 31, 2013 for incident PD diagnosis. We estimated hazard ratios and 95% confidence intervals using Cox regressions.Results: We observed 16,383 PD cases during on average 6.1 years of follow-up. Overall, use of beta 2AR agonists and montelukast were not related to PD incidence. A 38% lower PD incidence was noted among high-dose montelukast users when restricted to PD registered as the primary diagnosis.Interpretation: Overall, our data do not support inverse associations between beta 2AR agonists, montelukast, and PD. The prospect of lower PD incidence with high-dose montelukast exposure warrants further investigation, especially with adjustment for high-quality data on smoking. ANN NEUROL 2023
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| 11. |
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| 12. |
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| 13. |
- Lundholm, Karin, et al.
(författare)
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Fate of Cu, Cr and As during combustion of impregnated wood with and without peat additive
- 2007
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Ingår i: Environmental Science and Technology. - : American Chemical Society. - 0013-936X .- 1520-5851. ; 41:18, s. 6534-6540
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Tidskriftsartikel (refereegranskat)abstract
- The EU Directive on incineration of waste regulates the harmful emissions of particles and twelve toxic elements, including copper, chromium, and arsenic. More information is critically needed on the speciation and behavior of these trace elements during combustion, including the effects of different process variables, as well as of different fuels and fuel mixtures. Using a 15 kW pellets-fueled grate burner, experiments were performed to determine the fate of copper, chromium, and arsenic during combustion of chromate copper arsenate (CCA) preservative wood. The effects of co-combustion of CCA-wood with peat were also studied since peat fuels previously have proved to generally reduce ash related problems. The fate and speciation of copper, chromium, and arsenic were determined from analysis of the flue gas particles and the bottom ash using SEM-EDS, XRD, XPS, and ICP-AES. In addition, chemical equilibrium model calculations were performed to interpret the experimental findings. The results revealed that about 5% copper, 15% chromium, and 60% arsenic were volatilized during combustion of pure CCA-wood, which is lower than predicted volatilization from the individual arsenic, chromium, and copper oxides. This is explained by the formation of more stable refractory complex oxide phases for which the stability trends and patterns are presented. When co-combusted with peat, an additional stabilization of these phases was obtained and thus a small but noteworthy decrease in volatilization of all three elements was observed. The major identified phases for all fuels were CuCrO2(s), (Fe,Mg,Cu)(Cr,Fe,Al)O4(s), Cr2O3(s), and Ca3(AsO4)2(s). Arsenic was also identified in the fine particles as KH2AsO4(s) and As2O3(s). A strong indication of hexavalent chromium in the form of K2CrO4 or as a solid solution between K3Na(CrO4)2 and K3Na(SO4)2 was found in the fine particles. Good qualitative agreement was observed between experimental data and chemical equilibrium model calculations.
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| 14. |
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| 15. |
- Lundholm, Karin, et al.
(författare)
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Fate of Cu, Cr, and As during the combustion stages of CCA-treated wood fuel particles
- 2008
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 22:3, s. 1589-1597
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Tidskriftsartikel (refereegranskat)abstract
- A safe end-of-life management of the abundant chromated copper arsenate (CCA) preserved materials is 14 demanded for several environmental and health reasons. Thermal treatment as a disposal method will allow for efficient energy recovery and more controlled separation of the CCA elements, and potentially decrease leaching of toxic compounds into soils, lakes, and groundwater in the vicinity of landfills. However, this also leads to a potential risk of increased trace element emissions into the atmosphere. Developments in combustion science and technology have focused on decreasing emissions of particulates, sulfur and nitrogen oxides, but to fully control the fate of the trace elements through the thermal process and the subsequent flue gas cleaning process, the partitioning of these elements during combustion must be understood, especially for CCA-treated materials. The fate of the CCA elements during the different stages of combustion of impregnated wood was therefore explored. This paper compares the predicted results from chemical equilibrium modeling with results from laboratory-scale single-particle batch experiments. The results showed that a significant volatilization of arsenic was obtained experimentally, which the equilibrium calculations suggest is mainly related to the volatilization stage of combustion. The chemical equilibrium analysis showed to describe the overall behavior and fate of the three elements relatively well, since both degree of volatilization and solid phase compositions were quite in agreement between model and experimental results.
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| 16. |
- Lundholm, Karin, 1976-
(författare)
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Fate of Cu, Cr, As and some other trace elements during combustion of recovered waste fuels
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The increased use of biomass and recovered waste fuels in favor of fossil fuels for heat and power production is an important step towards a sustainable future. Combustion of waste fuels also offers several advantages over traditional landfilling, such as substantial volume reduction, detoxification of pathological wastes, and reduction of toxic leaches and greenhouse gas (methane) formation from landfills. However, combustion of recovered waste fuels emits more harmful trace elements than combustion of other fuels. These elements are distributed between bottom ash, fly ash and flue gas, depending on the elements partitioning and enrichment behavior. Volatilized harmful trace elements are mainly enriched in the submicron fly ash fraction. If emitted to the atmosphere, submicron particles can penetrate deep into the alveoli of the lungs, causing severe impacts on human health. Consequently, to reduce ash related problems and to control the emissions to the atmosphere, there is an increased need for understanding the physicochemical processes involved in ash transformation, including particle formation.The objective of this thesis was to carefully and systematically study the fate of trace elements during combustion, i.e. the chemical form of the elements and the partitioning behavior, by means of chemical equilibrium model calculations, X-ray diffraction, microscopy techniques and various spectroscopy methods. The influence of some fuel additives was also analyzed. Primarily, the elements copper, chromium and arsenic were studied.An initial review and evaluation of the content of thermodynamical data in commercial thermochemical databases used for chemical equilibrium model calculations showed that there was a significant difference in number of included phases and species between databases. Thermodynamical data also differed between databases, although in general less for condensed phases than for gaseous species. A state-of-the-art database for Cu, Cr and As was compiled and used for further chemical equilibrium model calculations. The fate of Cu, Cr and As was determined in combustion experiments on wood impregnated with copper, chromium and arsenic (CCA) in a bench scale reactor (15 kW). The results showed that global chemical equilibrium model calculations predicted the overall fate of Cu, Cr and As in bottom ash and ash particles quite well. However, compared to the experimental results the global model overpredicted the formation of refractory calcium arsenates, thus the arsenic volatilization was found to be higher then the predicted volatilization. In terms of chromium volatility, copper was found to be an important refractory element forming stable CuCrO2(s) and CuCr2O4(s) that suppressed the formation of CrO2(OH)2(g). The retention and speciation of Cu, Cr and As in bottom ash was further determined from combustion experiments of CCA wood fuel particles in a single particle reactor. Local chemical equilibrium model calculations were performed to simulate the combustion stages of a burning CCA treated wood fuel particle: drying, devolatilization, char burning and post-combustion. The results from the work showed that a mix of global and local chemical equilibrium model calculations is needed to describe the reality and that the combustion stages are partially overlapping. The fate of harmful trace elements, including Cu, Cr and As, was finally studied in full scale (65 MW) combustion experiments. Particles from the raw flue gas emissions were sampled and analyzed. The comparison with chemical equilibrium model calculations showed that the model explained the results well, but due to lack of thermodynamic data for K2ZnCl4(s), the formation of this phase could not be predicted.
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| 17. |
- Lundholm, Karin, et al.
(författare)
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Reduced bed agglomeration by co-combustion biomass with peat fuels in a fluidized bed
- 2005
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 19:6, s. 2273-2278
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Tidskriftsartikel (refereegranskat)abstract
- Fluidized bed combustion is an energy conversion technology that is very suitable for biomass combustion because of its fuel flexibility and low process temperatures. However, agglomeration of bed material may cause severe operating problems. To prevent or at least reduce this, peat has been suggested as an additive to the main fuels. Nevertheless, the characteristics of peat fuels vary and there is limited information of the effect of different peat fuels and of the mechanisms behind the agglomeration prevention. The objectives of the present work were therefore to: (i) quantify the potential positive effect by co-combustion peat with forest fuels in terms of initial agglomeration temperatures; (ii) determine the amount of peat fuel that is needed to significantly reduce the agglomeration tendencies; and, if possible, (iii) elucidate the governing mechanisms. The results showed that all peat fuels prevented agglomeration in the studied interval of 760-1020 °C and even as little as 5% peat fuel was found to have significant effects. The results also indicated that the mechanism of the agglomeration prevention varies between different peat fuels. Possible mechanisms are the minerals in the peat fuel retain alkali, which then is either elutriated up from the bed or captured in the bed; calcium and other refractory elements increase the melting temperature and thereby counteract the melting of alkali; and sulfur reacts with alkali metals and the alkali sulfates is either elutriated up from the bed or prevents agglomeration by increased melting temperature and lowered viscosity. Results from elemental analysis of the coating on bed particles showed that all mixtures with peat fuel resulted in a decreased or unchanged fraction of potassium and an increased fraction of aluminum in the coatings. The results also indicated a complex relationship between the fuel inorganic contents and the agglomeration process.
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| 18. |
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| 19. |
- Lundholm, Karin, et al.
(författare)
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Trace element speciation in combustion processes : review and compilatons of thermodynamic data
- 2007
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Ingår i: Fuel processing technology. - Amsterdam : Elsevier. - 0378-3820 .- 1873-7188. ; 88:11-12, s. 1061-1070
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Tidskriftsartikel (refereegranskat)abstract
- Chemical equilibrium calculations are often used to determine the fate of trace metals in combustion processes and to study the effects of different process variables and varying fuel compositions. In the present report, thermodynamic data on compounds containing the trace elements As, Cd, Cr, Cu and Pb from different database sources are compared. The results showed significant differences between existing databases in both number of compounds included in the databases and thermodynamic data. The differences also significantly affected the outcome of the equilibrium calculations.
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| 20. |
- Lundholm, Lovisa, et al.
(författare)
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Effects of estrogen on gene expression profiles in mouse hypothalamus and white adipose tissue: target genes include glutathione peroxidase 3 and cell death-inducing DNA fragmentation factor, alpha-subunit-like effector A.
- 2008
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Ingår i: The Journal of endocrinology. - 1479-6805. ; 196:3, s. 547-57
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Tidskriftsartikel (refereegranskat)abstract
- Obesity has become a major health problem in many parts of the world. Estrogens are known to reduce adipose tissue mass in both humans and animals but the molecular mechanisms are not well characterized. We used gene expression profiling to study long-term effects of estrogen on gene expression in mouse white adipose tissue and hypothalamus. Overall, the effects of estrogen on hypothalamic gene expression were much smaller than the corresponding effects on white adipose tissue gene expression. We characterize in detail estrogenic regulation of glutathione peroxidase 3 (GPX3). Our studies suggest that GPX3 is a direct estrogen receptor alpha target gene in white adipose tissue. Since obesity is correlated with oxidative stress, and GPX3 has been demonstrated to be lower in obesity and higher after weight loss, we hypothesize that GPX3 is one important mediator of effects of estrogen in relation to fat mass. Additional genes that were affected by estrogen in adipose tissue include cell death-inducing DNA fragmentation factor, alpha-subunit-like effector A (CIDEA), a gene shown to be related to body fat in mice. We conclude that estrogen has large effects on gene expression in white adipose tissue and hypothesize that GPX3 and CIDEA could be important mediators of the effects of estrogen on fat mass.
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| 21. |
- Lundholm, Lovisa, et al.
(författare)
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Gene expression profiling identifies liver X receptor alpha as an estrogen-regulated gene in mouse adipose tissue.
- 2004
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Ingår i: Journal of molecular endocrinology. - : Bioscientifica. - 0952-5041 .- 1479-6813. ; 32:3, s. 879-92
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Tidskriftsartikel (refereegranskat)abstract
- Estrogens reduce adipose tissue mass in both humans and animals. The molecular mechanisms for this effect are, however, not well characterized. We took a gene expression profiling approach to study the direct effects of estrogen on mouse white adipose tissue (WAT). Female ovariectomized mice were treated for 10, 24 and 48 h with 17beta-estradiol or vehicle. RNA was extracted from gonadal fat and hybridized to Affymetrix MG-U74Av2 arrays. 17beta-Estradiol was shown to decrease mRNA expression of liver X receptor (LXR) alpha after 10 h of treatment compared with the vehicle control. The expression of several LXRalpha target genes, such as sterol regulatory element-binding protein 1c, apolipoprotein E, phospholipid transfer protein, ATP-binding cassette A1 and ATP-binding cassette G1, was similarly decreased. We furthermore identified a 1.5 kb LXRalpha promoter fragment that is negatively regulated by estrogen. Several genes involved in lipogenesis and lipolysis were identified as novel targets that could mediate estrogenic effects on adipose tissue. Finally, we show that ERalpha is the main estrogen receptor expressed in mouse white adipose tissue (WAT) with mRNA levels several hundred times higher than those of ERbeta mRNA.
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| 22. |
- Thysell, Elin, et al.
(författare)
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Clinical and biological relevance of the transcriptomic-based prostate cancer metastasis subtypes MetA-C
- 2022
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Ingår i: Molecular Oncology. - : Wiley. - 1574-7891 .- 1878-0261. ; 16:4, s. 846-859
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Tidskriftsartikel (refereegranskat)abstract
- To improve treatment of metastatic prostate cancer, the biology of metastases needs to be understood. We recently described three subtypes of prostate cancer bone metastases (MetA-C), based on differential gene expression. The aim of this study was to verify the clinical relevance of these subtypes and to explore their biology and relations to genetic drivers. Freshly-frozen metastasis samples were obtained as hormone-naive (n = 17), short-term castrated (n = 21), or castration-resistant (n = 65) from a total of 67 patients. Previously published sequencing data from 573 metastasis samples were also analyzed. Through transcriptome profiling and sample classification based on a set of predefined MetA-C-differentiating genes, we found that most metastases were heterogeneous for the MetA-C subtypes. Overall, MetA was the most common subtype, while MetB was significantly enriched in castration-resistant samples and in liver metastases, and consistently associated with poor prognosis. By gene set enrichment analysis, the phenotype of MetA was described by high androgen response, protein secretion and adipogenesis, MetB by high cell cycle activity and DNA repair, and MetC by epithelial-to-mesenchymal transition and inflammation. The MetB subtype demonstrated single nucleotide variants of RB transcriptional corepressor 1 (RB1) and loss of 21 genes at chromosome 13, including RB1, but provided independent prognostic value to those genetic aberrations. In conclusion, a distinct set of gene transcripts can be used to classify prostate cancer metastases into the subtypes MetA-C. The MetA-C subtypes show diverse biology, organ tropism, and prognosis. The MetA-C classification may be used independently, or in combination with genetic markers, primarily to identify MetB patients in need of complementary therapy to conventional androgen receptor-targeting treatments.
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| 23. |
- Öhman, Marcus, et al.
(författare)
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Ash transformations during combustion of meat-, bonemeal, and RDF in a (bench-scale) fluidized bed combustor
- 2003
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 17:5, s. 1153-1159
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Tidskriftsartikel (refereegranskat)abstract
- Following the recent Bovine spongiform encephalopathy (BSE) experiences, thermal treatment of meat- and bonemeal (MBM) in existing fluidized bed combustion (FBC) plants for refuse-derived fuels (RDFs) has evolved as an interesting disposal and disintegration method. However, only a limited number of studies have previously been performed for combustion of MBM in fluidized beds. The objectives of the present work were, therefore, to determine the bed agglomeration tendencies of these materials during combustion in fluidized beds and to evaluate the effects of dolomite and kaolin addition to the fuel mix, as well as to elucidate the overall ash transformation mechanisms governing the potential bed agglomeration and fouling processes. By controlled agglomeration experiments in a 5 kW bench-scale fluidized bed reactor, the fuel-specific critical agglomeration temperatures in normal quartz bed material were determined for the different fuel/additive mixtures. All collected samples of bed materials, final bed agglomerates, and cyclone ashes were analyzed using SEM/EDS and XRD. The results indicated that the MBM fuels could be expected to be problematic concerning bed agglomeration in normal quartz beds, while kaolin and possibly dolomite addition could be used to reduce this risk to moderate levels. A significant elemental fractionation between the bed material and the cyclone ash was obtained. Apatite (Ca5(PO4)3(OH) or potentially some other calcium phosphates are elutriated from the bed and enriched in the fly ash, while sodium and potassium are enriched in the bed material. The characteristics and the corresponding melting behavior estimations of the necks formed between agglomerated bed particles suggest that silicate melts are responsible for the bed agglomeration. Results from XRD analysis of the fly ash formed from the fuels used in the present study indicated that the risk for melt-related fly ash problems seem relatively small.
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