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  • 201.
    Bidleman, Terry F.
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Centre for Atmospheric Research Experiments, Environment Canada, Ontario, Canada.
    Kurt-Karakus, Perihan B.
    Department of Environmental Engineering, Faculty of Natural Sciences, Architecture and Engineering, Bursa Technical University, Turkey.
    Wong, Fiona
    Department of Applied Environmental Science (ITM), Stockholm University.
    Alegria, Henry A.
    Department of Environmental Science, Policy and Geography, University of South Florida St. Petersburg, U.S.A..
    Jantunen, Liisa M.
    Centre for Atmospheric Research Experiments, Environment Canada, Ontario, Canada.
    Hung, Hayley
    Environment Canada, Ontario, Canada.
    Is there still “new” DDT in North America?: an investigation using proportions of DDT compounds2013Inngår i: Occurrence, fate and impact of atmospheric pollutants on environmental and human health / [ed] Laura L. McConnell, Jordi Dachs, Cathleen J. Hapeman, American Chemical Society (ACS), 2013, s. 153-181Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    Usage of DDT ceased over four decades ago in Canada and the United States, and since 2000 in Mexico. Potential sources in the North American atmosphere today include emissions of legacy residues from soils and long-range transport from other countries where DDT is still used or recently banned. Distinction of source types is investigated here using proportions of p,p′-DDT, o,p′-DDT, p,p′-DDE and p,p′-DDD. The relative volatilization of DDT compounds can be accurately described by their subcooled liquid vapor pressures (PL); e.g., (p,p′-DDT/p,p′-DDE)AIR = (p,p′-DDT/p,p′-DDE)SOIL x PL, DDT/PL,DDE. Using this model, the expected proportions in air due to volatilization from technical DDT and from soils in Canada, the U.S.A. and Mexico were estimated and expressed as the fractions FDDTE = p,p′-DDT/(p,p′-DDT + p,p′-DDE), FDDTO = p,p′-DDT/(p,p′-DDT + o,p′-DDT), and FDDTD = p,p′-DDT/(p,p′-DDT + p,p′-DDD). FDDTE, FDDTO and FDDTD predicted from soil emissions were compared to compound fractions in ambient air sampled at the Integrated Atmospheric Deposition Network (IADN) of stations on the Great Lakes between Canada and the U.S.A., and at arctic monitoring stations. FDDTE in air at IADN stations on lakes Erie, Ontario, Michigan and Huron were lower than in technical DDT vapor. This is consistent with emissions of aged residues from agricultural land and urban centers near these lakes. By comparison, FDDTE values were higher at stations on Lake Superior where atmospheric DDT is likely due to long-range transport rather than regional soil emissions. FDDTE increased from the early 1990s to 2005 at the Lake Superior stations and at the Canadian arctic station Alert between 2002-2005, whereas a significant decline in FDDTE was observed at the Norwegian arctic station Zeppelin Mountain. The mean FDDTO in air at IADN stations were consistent with either soil emissions or technical DDT composition, but annual values showed significant downward trends at two Canadian stations, and also decreased with time at Zeppelin Mountain (but not at Alert). These trends might signify contribution from “dicofol-type” DDT sources, which have a lower FDDTO than technical DDT or soil emissions, or preferential degradation of p,p′-DDT vs. o,p′-DDT over time. FDDTD in air at IADN stations were lower than in technical DDT vapor, showing the influence of soil sources. The enantiomer proportions of the chiral compounds o,p′-DDT and o,p′-DDD were nonracemic in some soils and ambient air, but enantiospecific analysis has not been done for IADN air samples. It is suggested that isomer, parent/metabolite and enantiomer composition information be incorporated into air monitoring programs to help identify sources.

  • 202.
    Bidleman, Terry F.
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Laudon, Hjalmar
    Nygren, Olle
    Lokalförsörjningsenheten, Umeå universitet.
    Svanberg, Staffan
    Tysklind, Mats
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Chlorinated pesticides and natural brominated anisoles in air at three northern Baltic stations2017Inngår i: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 225, s. 381-389Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Abstract Polyurethane foam (PUF) disk passive samplers were deployed at one inland and two island locations in the Bothnian Bay region of the northern Baltic Sea. Uptake was linear over 81–147 d and a temperature range of −2.6 to 14.2 °C for organochlorine pesticides (OCPs) and current-use pesticides (CUPs) having log KOA ≥9 at ambient temperatures. Partial saturation of the PUF disks occurred for the more volatile OCPs hexachlorocyclohexanes (HCHs) and hexachlorobenzene (HCB), and for bromoanisoles (BAs), which are products of bromophenols released by natural and anthropogenic sources. Correction for nonlinear uptake of these was made using experimentally measured PUF-air partition coefficients. Passive-derived air concentrations of pesticides were uniform over the bay and agreed within a factor of 2 or better with levels determined by active (pumped) sampling at one of the island stations. Levels of OCPs were similar to those reported at background sites in the European and Canadian Arctic and at monitoring stations in the central Baltic and southern Scandinavia, indicating long-range transport. The insecticide chlorpyrifos was 10 times lower at bay stations than in the Canadian Arctic. Insight to sources and processes was gained by examining compound profiles. Fractions Falpha = α-HCH/(α-HCH + γ-HCH) and FTC = trans-chlordane/(trans-chlordane + cis-chlordane) at bay stations were higher than in the Norwegian and Finnish Arctic and similar to those at the southern monitoring stations. Volatilization of chlordanes from Baltic seawater may also modify FTC. Higher FTriBA = 2,4,6-TriBA/(2,4,6-TriBA + 2,4-DiBA) distinguished local volatilization from the Baltic Sea versus lower FTriBA found at the inland site and reported in air on the Norwegian coast, suggesting westerly transport from the Atlantic across Norway and Sweden.

  • 203.
    Bidleman, Terry F.
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Nygren, Olle
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Tysklind, Mats
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Field estimates of polyurethane foam: air partition coefficients for hexachlorobenzene, alpha-hexachlorocyclohexane and bromoanisoles2016Inngår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 159, s. 126-131Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Partition coefficients of gaseous semivolatile organic compounds (SVOCs) between polyurethane foam (PUF) and air (KPA) are needed in the estimation of sampling rates for PUF disk passive air samplers. We determined KPA in field experiments by conducting long-term (24-48 h) air sampling to saturate PUF traps and shorter runs (2-4 h) to measure air concentrations. Sampling events were done at daily mean temperatures ranging from 1.9 to 17.5 °C. Target compounds were hexachlorobenzene (HCB), alpha-hexachlorocyclohexane (α-HCH), 2,4-dibromoanisole (2,4-DiBA) and 2,4,6-tribromoanisole (2,4,6-TriBA). KPA (mL g(-1)) was calculated from quantities on the PUF traps at saturation (ng g(-1)) divided by air concentrations (ng mL(-1)). Enthalpies of PUF-to-air transfer (ΔHPA, kJ mol(-1)) were determined from the slopes of log KPA/mL g(-1) versus 1/T(K) for HCB and the bromoanisoles, KPA of α-HCH was measured only at 14.3 to 17.5 °C and ΔHPA was not determined. Experimental log KPA/mL g(-1) at 15 °C were HCB = 7.37; α-HCH = 8.08; 2,4-DiBA = 7.26 and 2,4,6-TriBA = 7.26. Experimental log KPA/mL g(-1) were compared with predictions based on an octanol-air partition coefficient (log KOA) model (Shoeib and Harner, 2002a) and a polyparameter linear free relationship (pp-LFER) model (Kamprad and Goss, 2007) using different sets of solute parameters. Predicted KP values varied by factors of 3 to over 30, depending on the compound and the model. Such discrepancies provide incentive for experimental measurements of KPA for other SVOCs.

  • 204.
    Bidleman, Terry F.
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Tysklind, Mats
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Breakthrough during air sampling with polyurethane foam: What do PUF 2/PUF 1 ratios mean?2018Inngår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 192, s. 267-271Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Frontal chromatography theory is applied to describe movement of gaseous semivolatile organic compounds (SVOCs) through a column of polyurethane foam (PUF). Collected mass fractions (FC) are predicted for sample volume/breakthrough volume ratios (τ = VS/VB) up to 6.0 and PUF bed theoretical plate numbers (N) from 2 to 16. The predictions assume constant air concentrations and temperatures. Extension of the calculations is done to relate the collection efficiency of a 2-PUF train (FC1+2) to the PUF 2/PUF 1 ratio. FC1+2 exceeds 0.9 for PUF 2/PUF 1 ≤ 0.5 and lengths of PUF commonly used in air samplers. As the PUF 2/PUF 1 ratio approaches unity, confidence in these predictions is limited by the analytical ability to distinguish residues on the two PUFs. Field data should not be arbitrarily discarded because some analytes broke through to the backup PUF trap. The fractional collection efficiencies can be used to estimate air concentrations from quantities retained on the PUF trap when sampling is not quantitative.

  • 205.
    Bidleman, Terry Frank
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Air Quality Processes Research Section, Environment Canada.
    Jantunen, L. M.
    Hung, H.
    Ma, J.
    Stern, G. A.
    Rosenberg, B.
    Racine, J.
    Annual cycles of organochlorine pesticide enantiomers in Arctic air suggest changing sources and pathways2015Inngår i: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 15, nr 3, s. 1411-1420Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Air samples collected during 1994-2000 at the Canadian Arctic air monitoring station Alert (82 degrees 30'N, 62 degrees 20'W) were analysed by enantiospecific gas chromatography-mass spectrometry for alpha-hexachlorocyclohexane (alpha-HCH), trans-chlordane (TC) and cis-chlordane (CC). Results were expressed as enantiomer fractions (EF = peak areas of (+)/[(+) + (-)] enantiomers), where EFs = 0.5, <0.5 and >0.5 indicate racemic composition, and preferential depletion of (+) and (-) enantiomers, respectively. Long-term average EFs were close to racemic values for alpha-HCH (0.504 +/- 0.004, n = 197) and CC (0.505 +/- 0.004, n = 162), and deviated farther from racemic for TC (0.470 +/- 0.013, n = 165). Digital filtration analysis revealed annual cycles of lower alpha-HCH EFs in summer-fall and higher EFs in winter-spring. These cycles suggest volatilization of partially degraded alpha-HCH with EF < 0.5 from open water and advection to Alert during the warm season, and background transport of alpha-HCH with EF > 0.5 during the cold season. The contribution of sea-volatilized alpha-HCH was only 11% at Alert, vs. 32% at Resolute Bay (74.68 degrees N, 94.90 degrees W) in 1999. EFs of TC also followed annual cycles of lower and higher values in the warm and cold seasons. These were in phase with low and high cycles of the TC / CC ratio (expressed as F-TC = TC/(TC + CC)), which suggests greater contribution of microbially "weathered" TC in summer-fall versus winter-spring. CC was closer to racemic than TC and displayed seasonal cycles only in 1997-1998. EF profiles are likely to change with rising contribution of secondary emission sources, weathering of residues in the environment, and loss of ice cover in the Arctic. Enantiomer-specific analysis could provide added forensic capability to air monitoring programs.

  • 206.
    Bidleman, Terry Frank
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Centre for Atmospheric Research Experiments, Environment Canada, Canada.
    Jantunen, Liisa M.
    Binnur Kurt-Karakus, Perihan
    Wong, Fiona
    Hung, Hayley
    Ma, Jianmin
    Stern, Gary
    Rosenberg, Bruno
    Chiral Chemicals as Tracers of Atmospheric Sources and Fate Processes in a World of Changing Climate2013Inngår i: Mass Spectrometry, ISSN 2186-5116, Vol. 2, nr 19, Special Issue: Proceedings of 19th International Mass Spectrometry Conference, s. S0019-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Elimination of persistent organic pollutants (POPs) under national and international regulations reduces “primary” emissions, but “secondary” emissions continue from residues deposited in soil, water, ice and vegetation during former years of usage. In a future, secondary source controlled world, POPs will follow the carbon cycle and biogeochemical processes will determine their transport, accumulation and fate. Climate change is likely to affect mobilisation of POPs through e.g., increased temperature, altered precipitation and wind patterns, flooding, loss of ice cover in polar regions, melting glaciers, and changes in soil and water microbiology which affect degradation and transformation. Chiral compounds offer advantages for following transport and fate pathways because of their ability to distinguish racemic (newly released or protected from microbial attack) and nonracemic (microbially degraded) sources. This paper discusses the rationale for this approach and suggests applications where chiral POPs could aid investigation of climate-mediated exchange and degradation processes. Multiyear measurements of two chiral POPs, trans-chlordane and α-HCH, at a Canadian Arctic air monitoring station show enantiomer compositions which cycle seasonally, suggesting varying source contributions which may be under climatic control. Large-scale shifts in the enantioselective metabolism of chiral POPs in soil and water might influence the enantiomer composition of atmospheric residues, and it would be advantageous to include enantiospecific analysis in POPs monitoring programs.

  • 207.
    Bidleman, Terry Frank
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Centre for Atmospheric Research Experiments (CARE), Environment Canada, 6248 Eighth Line, Egbert, ON, L0L 1N0, Canada.
    Stern, Gary A.
    Tomy, Gregg T.
    Hargrave, Barry T.
    Jantunen, Liisa M.
    Macdonald, Robie W.
    Scavenging amphipods: sentinels for penetration of mercury and persistent organic chemicals into food webs of the deep arctic ocean2013Inngår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 47, nr 11, s. 5553-5561Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Archived specimens of the scavenging amphipod Eurythenes gryllus, collected from 2075 to 4250 m below the surface on five expeditions to the western and central Arctic Ocean between 1983 and 1998, were analyzed for total mercury (∑Hg), methyl mercury (MeHg), polychlorinated biphenyls (PCBs) and other industrial or byproduct organochlorines (chlorobenzenes, pentachloroanisole, octachlorostyrene), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs). Median ∑Hg concentrations ranged from 70 to 366 ng g(-1) wet weight (ww). MeHg concentrations (3.55 to 23.5 ng g(-1) ww) accounted for 1.7 to 20.1% (median 3.7%) of ∑Hg. ∑Hg and MeHg were positively and significantly correlated with ww (∑Hg r(2) = 0.18, p = 0.0004, n = 63; MeHg r(2) = 0.42, p = 0.0004, n = 25), but not significantly with δ(13)C nor δ(15)N. Median concentrations of total persistent organic pollutants (POPs) ranged from 9750 to 156 000 ng g(-1) lipid weight, with order of abundance: ∑TOX (chlorobornanes quantified as technical toxaphene) > ∑PCBs > ∑DDTs > ∑chlordanes > ∑mirex compounds > ∑BDEs ∼ ∑chlorobenzenes ∼ octachlorostyrene > α-hexachlorocyclohexane ∼ hexachlorobenzene ∼ pentachloroanisole. Enantioselective accumulation was found for the chiral OCPs o,p'-DDT, cis- and trans-chlordane, nonachlor MC6 and oxychlordane. Lipid-normalized POPs concentrations were elevated in amphipods with lipid percentages ≤10%, suggesting that utilization of lipids resulted in concentration of POPs in the remaining lipid pool. Multidimensional Scaling (MDS) analysis using log-transformed physiological variables and lipid-normalized organochlorine concentrations distinguished amphipods from the central vs western arctic stations. This distinction was also seen for PCB homologues, whereas profiles of other compound classes were more related to specific stations rather than central-west differences.

  • 208. Biryulin, YF
    et al.
    Kurdybaylo, D
    Shamanin, V
    Aleksjuk, G
    Volkova, T
    Melenevskaya, E
    Saydashev, I
    Eidelman, E
    Makarova, Tatiana
    Ioffe Physico-Technical Institute RAS, Russia.
    Terukov, E
    Zaitseva, N
    Negrov, V
    Tkatchyov, A
    Strongly non-linear carbon nanofibre influence on electrical properties of polymer composites2008Inngår i: Fullerenes, nanotubes, and carbon nanostructures (Print), ISSN 1536-383X, E-ISSN 1536-4046, Vol. 16, nr 5-6, s. 629-633Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Composites of carbon nanofibres (CNF) (30-50 nm diam., length up to 1 mu m) in two polymer matrices (polybutadiene-styrene and polypyrrhol) show strong non-linearities of conductivity vs. CNF concentration. We have studied their voltage-current dependencies, and observed correlation of their extrema and layer morphology. Multistability of conductivity is discovered, with apparent effect of magnetic field effect on it in polypyrrhol-based composites. In addition CNF spatial configuration influence on layers' conductivity is discussed.

  • 209. Biswal, Ajaya K.
    et al.
    Soeno, Kazuo
    Gandla, Madhavi Latha
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Immerzeel, Peter
    Pattathil, Sivakumar
    Lucenius, Jessica
    Serimaa, Ritva
    Hahn, Michael G.
    Moritz, Thomas
    Jönsson, Leif J.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Israelsson-Nordstrom, Maria
    Mellerowicz, Ewa J.
    Aspen pectate lyase PtxtPL1-27 mobilizes matrix polysaccharides from woody tissues and improves saccharification yield2014Inngår i: Biotechnology for Biofuels, ISSN 1754-6834, E-ISSN 1754-6834, Vol. 7, s. 11-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: Wood cell walls are rich in cellulose, hemicellulose and lignin. Hence, they are important sources of renewable biomass for producing energy and green chemicals. However, extracting desired constituents from wood efficiently poses significant challenges because these polymers are highly cross-linked in cell walls and are not easily accessible to enzymes and chemicals. Results: We show that aspen pectate lyase PL1-27, which degrades homogalacturonan and is expressed at the onset of secondary wall formation, can increase the solubility of wood matrix polysaccharides. Overexpression of this enzyme in aspen increased solubility of not only pectins but also xylans and other hemicelluloses, indicating that homogalacturonan limits the solubility of major wood cell wall components. Enzymatic saccharification of wood obtained from PL1-27-overexpressing trees gave higher yields of pentoses and hexoses than similar treatment of wood from wild-type trees, even after acid pretreatment. Conclusions: Thus, the modification of pectins may constitute an important biotechnological target for improved wood processing despite their low abundance in woody biomass.

  • 210. Bjarnsholt, T.
    et al.
    Buhlin, K.
    Dufrêne, Y. F.
    Gomelsky, M.
    Moroni, A.
    Ramstedt, Madeleine
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Rumbaugh, K. P.
    Schulte, T.
    Sun, L.
    Åkerlund, B.
    Römling, U.
    Biofilm formation – what we can learn from recent developments2018Inngår i: Journal of Internal Medicine, ISSN 0954-6820, E-ISSN 1365-2796, Vol. 284, nr 4, s. 332-345Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Although biofilms have been observed early in the history of microbial research, their impact has only recently been fully recognized. Biofilm infections, which contribute to up to 80% of human microbial infections, are associated with common human disorders, such as diabetes mellitus and poor dental hygiene, but also with medical implants. The associated chronic infections such as wound infections, dental caries and periodontitis significantly enhance morbidity, affect quality of life and can aid development of follow-up diseases such as cancer. Biofilm infections remain challenging to treat and antibiotic monotherapy is often insufficient, although some rediscovered traditional compounds have shown surprising efficiency. Innovative anti-biofilm strategies include application of anti-biofilm small molecules, intrinsic or external stimulation of production of reactive molecules, utilization of materials with antimicrobial properties and dispersion of biofilms by digestion of the extracellular matrix, also in combination with physical biofilm breakdown. Although basic principles of biofilm formation have been deciphered, the molecular understanding of the formation and structural organization of various types of biofilms has just begun to emerge. Basic studies of biofilm physiology have also resulted in an unexpected discovery of cyclic dinucleotide second messengers that are involved in interkingdom crosstalk via specific mammalian receptors. These findings even open up new venues for exploring novel anti-biofilm strategies.

  • 211.
    Björklund, Sofie
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Naturally ProducedOrganohalogens in Algae from the Baltic Sea and the Swedish West Coast2018Independent thesis Advanced level (degree of Master (Two Years)), 30 poäng / 45 hpOppgave
  • 212.
    Björkman, Bo
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Quantitative equilibrium calculations on systems with relevance to copper smelting and converting1984Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The present thesis gives a summary of results obtained through theoretical and experimental studies of systems with relevance to copper smelting and converting.

    Many chemical elements are involved in the copper production pro­cesses and a detailed experimental study would be very time- consuming and expensive. A complicating fact is also the corrosivity of the liquid phases towards container material. A powerful alternative is equilibrium calculations, in which models for the liquid phases as well as reliable basic thermodynamic data are needed.

    In the present thesis, a generalized structure based model for liquid silicates was developed and used in assessments of the sys­tems PbO-SiO2, Fe-O-SiO2, CuO0.5-SÌO2 and Cu-Fe-O-SiO2. In the model, the non-ideal silicate melt is treated as an ideal solu­tion but containing a few complexes. The PbO-Si02 melt could be described by introducing the complexes Pb3Si207, Pb4Si4010 and Pb13Si12O37 in addition to the components PbO and Pb2Si04. The species considered in the Fe-O-SiO2 melt were FeO, FeO1.5, Fe2Si04, Fe3Si207, Fe3Si6O15 and in the CUO0.5-SiO2 melt CuO0.5 ana CU4SiO4. Trie calculated phase diagrams, the activities of me­tal oxides and the oxygen partial pressures were all in good agreement with the published data.

    Two of the papers in this thesis concern the determination of Gibbs free energies for Cu2S(s,l) and Ca2Fe2O5(s) through emf measurements utilizing a solid electrolyte. Activities and termi­nal solubilities in the solid solution [Fet,Ca]0 were also deter­mined.

    The results obtained from the quantitative equilibrium calcula­tions for conventional copper smelting and converting were used to outline the overall reactions taking place and the outcome of changes in process parameters. Comparison with observed values, however, showed that the copper and magnetite contents in slag were calculated too low. These discrepancies could be completely explained by using a non-equilibrium approach in which the con­verter was assumed to consist of several segments with concentra­tion gradients between the segments.

  • 213. Björlenius, Berndt
    et al.
    Ripszám, Mátyás
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Haglund, Peter
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Lindberg, Richard H.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Tysklind, Mats
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Fick, Jerker
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Pharmaceutical residues are widespread in Baltic Sea coastal and offshore waters: Screening for pharmaceuticals and modelling of environmental concentrations of carbamazepine2018Inngår i: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 633, s. 1496-1509Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The consumption of pharmaceuticals worldwide coupled with modest removal efficiencies of sewage treatment plants have resulted in the presence of pharmaceuticals in aquatic systems globally. In this study, we investigated the environmental concentrations of a selection of 93 pharmaceuticals in 43 locations in the Baltic Sea and Skagerrak. The Baltic Sea is vulnerable to anthropogenic activities due to a long turnover time and a sensitive ecosystem in the brackish water. Thirty-nine of 93 pharmaceuticals were detected in at least one sample, with concentrations ranging between 0.01 and 80 ng/L. One of the pharmaceuticals investigated, the anti-epileptic drug carbamazepine, was widespread in coastal and offshore seawaters (present in 37 of 43 samples). In order to predict concentrations of pharmaceuticals in the sub-basins of the Baltic Sea, a mass balance-based grey box model was set up and the persistent, widely used carbamazepine was selected as the model substance. The model was based on hydrological and meteorological sub-basin characteristics, removal data from smaller watersheds and wastewater treatment plants, and statistics relating to population, consumption and excretion rate of carbamazepine in humans. The grey box model predicted average environmental concentrations of carbamazepine in sub-basins with no significant difference from the measured concentrations, amounting to 0.57–3.2 ng/L depending on sub-basin location. In the Baltic Sea, the removal rate of carbamazepine in seawater was estimated to be 6.2 10−9 s−1 based on a calculated half-life time of 3.5 years at 10 °C, which demonstrates the long response time of the environment to measures phasing out persistent or slowly degradable substances such as carbamazepine. Sampling, analysis and grey box modelling were all valuable in describing the presence and removal of carbamazepine in the Baltic Sea.

  • 214.
    Björnberg, Arne
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten.
    Crystal structure studies of a new series of molybdovanadate polyanions and some related vanadates1980Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The determination of complexes formed in weakly acidic aqueous solutions containing pentavalent vanadium as well as hexavalent molybdenum has proved diffi cui t due to slow equilibria and 1 imi ted sol ubi 1 i ty of especially the vanadium species. The formation of several different polynuclear complexes with a very varied molybdenum/vanadium ratio also complicates the interpretation of Potentiometrie data. In order to clarify the picture of complexes formed and provide starting points for equilibrium calculations single-crystal X-ray studies were made on crystals obtained from âqueous solutions. In addition, these studies can provide information on bonding conditions and possibly formation mechanisms for molybdovanadate polyanions. Crystals were synthesized by slow evaporation of aqueous solutions. Solutions with varied molybdenum/vanadium ratios and also varied pH values were prepared and used in the synthesis experiments. The X-ray measurements were performed with Philips PAILRED, Syntex P21 and Syntex R3 automatic diffractometers. All data sets were corrected for absorption. Five of the structures were solved with heavy-atom methods and one by direct methods. The structures were refined by computer-performed least-squares methods. The following crystals were obtained and structurally determined: NaV03•1.89H2O, which contains chains of VO5 trigonal bipyramids. Na4V2O7 (H2O)18 , containing discrete V2O74- anions which are completely surrounded by sodium-coordinated water molecules. Discrete molybdovanadate polyanions were found in the structures of the compounds Na6Mo6\/2O26 (H2O)16 , K7Mo8V5O40 • 8H2O, K8Mo4,V8O36 - 12H20 and K6 (V2 , Mo10) VO40 • 13H20. The last substance belongs to a class of compounds named 'heteropoly blues', which contain metal atoms in mixed-valence states, and has one unpaired electron on the polyanion. This compound was also investigated with electron spin resonance spectroscopy. The bonding configurations of oxygen atoms coordinated to molybdenum or vanadium are described and discussed. As the Mo4V8O368-, Mo8V5O407- (which is an isomer of the Keggin anion but has a quite different structure) and Mo6V2O266- anions all contain remnants of mononuclear molybdate and vanadate anions, it seems likely that these polyanions are formed mainly through the condensation of mononuclear species.An electrostatic model for the simulation of bond distances in polyions, starting with perfectly regular idealized models, is presented.

  • 215.
    Blomberg, David
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Kemi.
    Synthesis of β-turn and pyridine based peptidomimetics2007Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Despite the unfavorable pharmacokinetic properties associated with peptides, they are still of great interest in drug development due to a multitude of interesting biological functions. The development of peptidomimetics strives to maintain or improve the biological activity of a peptide concurrently with removing the unwanted properties. This thesis describes two synthetic approaches to peptidomimetics with particular emphasis on secondary structure mimetics.

    First the design, synthesis and evaluation of two beta-turn mimetics incorporated in the endorphin Leu-enkephalin is presented. The beta-turn mimetics were stabilized by replacement of the intramolecular hydrogen bond with an ethylene bridge, and the amide bond between Tyr and Gly was replaced with an ether linkage. Linear analogues of the two mimetics were also synthesized. The peptidomimetics and their linear analogues were evaluated in a competitive binding assay at two opiate receptors, my and delta. One of the cyclized beta-turn mimetics was found to be a delta receptor antagonist with an IC50 value of 160 nM.

    Second a synthetic strategy to a beta-strand mimetic using 2-fluoro-4-iodopyridine as scaffold is described. The synthesis involved a Grignard exchange reaction on the pyridine scaffold using an amino acid derivative as electrophile followed by an SNAr reaction using an amine as nucleophile. The synthesis of a tripeptidomimetic of Leu-Gly-Gly and attempts to introduce chiral building blocks at the C-terminal, as well as studies towards elongated mimetics are presented.

    Two additional studies deal with the synthesis of two classes of potential thrombin inhibitors based on the pyridine scaffold. The first class contain pyridine as central fragment (P2 residue) substituted with a para-amidinobenzylamine group as P1 residue and various benzoyl groups as P3 residues. Three potential thrombin inhibitors were synthesized and found to be microM inhibitors in an enzymatic assay. In the second class, the pyridine ring serves as P3 residue. This class also lacks a strongly basic group in the P1 position. A small library of eight compounds were synthesized and evaluated in the enzymatic assay. Unfortunately, these compounds lacked inhibitory activity.

  • 216.
    Blomberg, David
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Hedenström, Mattias
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Kreye, Paul
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Sethson, Ingmar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Brickmann, Kay
    AstraZeneca R&D Mölndal, Mölndal, Sweden.
    Kihlberg, Jan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Synthesis and conformational studies of a β-turn mimetic incorporated in Leu-enkephalin2004Inngår i: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 69, nr 10, s. 3500-3508Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A β-turn mimetic in which the four amino acids of a β-turn have been replaced by a 10-membered ring has been designed, synthesized, and subjected to conformational studies. In the mimetic, the intramolecular COi − HNi+3 hydrogen bond that is often found in β-turns has been replaced by an ethylene bridge. In addition, the amide bond between residues i and i + 1 was exchanged for a methylene ether isoster. Such a β-turn mimetic, based on the first four residues of Leu-enkephalin (Tyr-Gly-Gly-Phe-Leu), was prepared in 15 steps. The synthesis relied on a β-azido alcohol prepared in five steps from Cbz-Tyr(tBu)-OH as a key, i-position building block. tert-Butyl bromoacetate, glycine, and a Phe-Leu dipetide were then used as building blocks for positions i + 1, i + 2, and i + 3, respectively. Conformational studies based on 1H NMR data showed that the β-turn mimetic was flexible, but that it resembled a type-II β-turn at low temperature. This low energy conformer closely resembled the structure determined for crystalline Leu-enkephalin.

  • 217.
    Blum, Kristin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Phototransformation of pharmaceuticals in the environment: Multivariate modeling and experimental determination of photolysis half-lives2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
  • 218.
    Blum, Kristin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Targeted and untargeted analysis of organic contaminants from on-site sewage treatment facilities: Removal, fate and environmental impact2018Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    On-site sewage treatment facilities (OSSFs) are widely used all over the world to treat wastewater when large-scale sewage treatment plants (STPs) are not economically feasible. Although there is great awareness that the release of untreated wastewater into the environment can lead to water-related diseases and eutrophication, little is known about organic contaminants and their removal by OSSFs, environmental load and fate. Thus, this PhD thesis aims to improve the knowledge about treatment efficiencies in current OSSFs, the environmental impact and fate of contaminants released from OSSFs, as well as how biochar fortification in sand filter (soil beds) OSSFs might increase removal of these contaminants. State-of-the-art analytical techniques for untargeted and targeted analyses were used and the results evaluated with univariate and multivariate statistics.

    Environmentally-relevant contaminants discharged from OSSFs were identified using untargeted analysis with two-dimensional gas chromatography mass spectrometry (GC×GC-MS) and a MS (NIST) library search in combination with a prioritization strategy based on environmental relevance. A method was successfully developed for the prioritized contaminants using solid phase extraction and GC×GC-MS, and the method was also applicable to untargeted analysis. This method was applied to several studies. The first study compared treatment efficiencies between STP and soil beds and showed that treatment efficiencies are similar or better in soil beds, but the removal among the same type of treatment facilities and contaminants varied considerably. Hydrophilic contaminants were generally inadequately removed in both types of treatment facilities and resulted in effluent levels in the nanogram per liter range.

    Additionally, several prioritized and sometimes badly removed compounds were found to be persistent, mobile, and bioavailable and two additional, untargeted contaminants identified by the NIST library search were potentially mobile. These contaminants were also found far from the main source, a large-scale STP, at Lake Ekoln, which is part of the drinking water reservoir Lake Mälaren, Sweden. The study also showed that two persistent, mobile and bioavailable contaminants were additionally bioaccumulating in perch. Sampling for this study was carried out over several seasons in the catchment of the River Fyris. Parts of this catchment were affected by OSSFs, other parts by STPs. Potential ecotoxicological risks at these sites were similar or higher at those affected by STPs compared to those affected by OSSFs. Mass fluxes per capita were calculated from these levels, which were higher at STP-affected than at OSSF-affected sites in summer and autumn, but not in winter. Possibly, the diffuse OSSF emissions occur at greater average distances from the sampling sites than the STP point emissions, and OSSF-affected sites may consequently be more influenced by fate processes.

    The studies carried out suggested that there is a need to improve current treatment technologies for the removal of hydrophilic contaminants. Thus, the final study of this thesis investigated char-fortified sand filters (soil beds) as potential upgrades for OSSFs using a combination of advanced chemical analysis and quantitative structure-property relationship modeling. Removal efficiencies were calculated from a large variety of contaminants that were identified by untargeted analysis using GC×GC-MS and liquid chromatography ion mobility mass spectrometry as well as library searches (NIST and Agilent libraries). On average, char-fortified sand filters removed contaminants better than sand, partly due to an enhanced removal of several hydrophilic contaminants with heteroatoms. After a two-year runtime, sorption and particularly biodegradation must have contributed to the removal of these compounds.

    Generally, the combination of targeted and untargeted analysis has proven valuable in detecting a large variety of organic contaminants, as well as unexpected ones. The results imply that OSSFs have similar or better removal efficiencies, similar or lower environmental risks and similar or lower mass fluxes per capita, compared to STPs. Biochar fortification can improve the removal of organic contaminants in soil beds, but further research is needed to find technologies that reduce the discharge of all types of organic contaminants.

  • 219.
    Blum, Kristin M.
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Andersson, Patrik L.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Renman, Gunno
    Ahrens, Lutz
    Gros, Meritxell
    Wiberg, Karin
    Haglund, Peter
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Non-target screening and prioritization of potentially persistent, bioaccumulating and toxic domestic wastewater contaminants and their removal in on-site and large-scale sewage treatment plants2017Inngår i: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 575, s. 265-275Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    On-site sewage treatment facilities (OSSFs), which are used to reduce nutrient emissions in rural areas, were screened for anthropogenic compounds with two-dimensional gas chromatography–mass spectrometry (GC × GC–MS). The detected compounds were prioritized based on their persistence, bioaccumulation, ecotoxicity, removal efficiency, and concentrations. This comprehensive prioritization strategy, which was used for the first time on OSSF samples, ranked galaxolide, α-tocopheryl acetate, octocrylene, 2,4,7,9-tetramethyl-5-decyn-4,7-diol, several chlorinated organophosphorus flame retardants and linear alkyl benzenes as the most relevant compounds being emitted from OSSFs. Twenty-six target analytes were then selected for further removal efficiency analysis, including compounds from the priority list along with substances from the same chemical classes, and a few reference compounds. We found significantly better removal of two polar contaminants 2,4,7,9-tetramethyl-5-decyn-4,7-diol (p = 0.0003) and tris(2-butoxyethyl) phosphate (p = 0.005) in soil beds, a common type of OSSF in Sweden, compared with conventional sewage treatment plants. We also report median removal efficiencies in OSSFs for compounds not studied in this context before, viz. α-tocopheryl acetate (96%), benzophenone (83%), 2-(methylthio)benzothiazole (64%), 2,4,7,9-tetramethyl-5-decyn-4,7-diol (33%), and a range of organophosphorus flame retardants (19% to 98%). The environmental load of the top prioritized compounds in soil bed effluents were in the thousands of nanogram per liter range, viz. 2,4,7,9-tetramethyl-5-decyn-4,7-diol (3000 ng L− 1), galaxolide (1400 ng L− 1), octocrylene (1200 ng L− 1), and α-tocopheryl acetate (660 ng L− 1).

  • 220.
    Blum, Kristin M.
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Umeå University.
    Gallampois, Christine
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Andersson, Patrik L.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Renman, G.
    Renman, A.
    Haglund, Peter
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Comprehensive assessment of organic contaminant removal from on-site sewage treatment facility effluent by char-fortified filter beds2019Inngår i: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 361, s. 111-122Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    The removal of organic contaminants from wastewater using cost-efficient and easily accessible methods have been increasingly studied in recent years. Most studies have focused on municipal sewage treatment plants; however, our study investigated treatment with char-fortified filter beds for on-site sewage treatment facilities (OSSFs). OSSFs are commonly used in rural and semi-urban areas all over the world to treat wastewater to reduce eutrophication and water-related diseases. To screen for a wide range of organic contaminants in order to improve the understanding of wastewater treatment efficiency and molecular properties, samples were taken from an OSSF field study site that used three filter types: sand, char-fortified sand, and char-fortified gas concrete. First, we screened for organic contaminants with state-of-the-art gas chromatography and liquid chromatography mass spectrometry-based targeted and untargeted analysis and then we developed quantitative structure-property relationship models to find the key molecular features responsible for the removal of organic contaminants. We identified 74 compounds, of which 24 were confirmed with reference standards. Amongst these 74 compounds were plasticizers, UV stabilizers, fragrances, pesticides, surfactant and polymer impurities, pharmaceuticals and their metabolites, and many biogenic compounds. Sand filters that are sometimes used as a last treatment step in OSSFs can remove hydrophobic contaminants. The addition of biochar significantly increases the removal of these and a few hydrophilic compounds (Wilcoxon signed-rank test, α = 0.05). Gas concrete did not appear to be suitable for the removal of organic contaminants. This study showed that, besides hydrophobic effects, biodegradation is the most important removal pathway in long-term field applications. However, further improvements are necessary to remove very hydrophilic contaminants as they were not removed with sand and biochar-fortified sand.

  • 221.
    Blum, Kristin M.
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Umeå University.
    Haglund, Peter
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Gao, Qiuju
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Ahrens, L.
    Gros, M.
    Wiberg, K.
    Andersson, Patrik L.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Mass fluxes per capita of organic contaminants from on-site sewage treatment facilities2018Inngår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, nr 201, s. 864-873Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    This study is the first attempt to quantify environmental fluxes per capita of organic contaminants discharged from on-site sewage treatment facilities (OSSFs) in affected recipients. Five sites were monitored around the River Fyris in Sweden: three mainly affected by OSSFs and two mainly affected by municipal sewage treatment plants (STPs). Gas chromatography-mass spectrometry was used to determine environmental concentrations of 30 anthropogenic contaminants, including organophosphorus compounds, rubber and plastic additives, UV stabilizers, fragrances, surfactant ingredients and polycyclic aromatic hydrocarbons. Uni- and multivariate statistical analysis of the most frequently detected contaminants showed that median fluxes per capita of tris(1,3-dichloro-2-propyl) phosphate, tris(1-chloro-2-propyl) phosphate, tris(2-chloroethyl) phosphate, and n-butylbenzene sulfonamide were similar at OSSF and STP sites, but the mass fluxes per capita of tris-(2-butoxyethyl) phosphate, 2-(methylthio)benzothiazole, and galaxolide, were significantly lower (~2 to 3-fold) at OSSF sites than at STP sites (Mann-Whitney, α = 0.05). Differences between these sites were larger in samples collected in summer and autumn than in samples collected in winter. Deviations likely originated from differences in treatment technology and distances between source and sampling sites. Further studies are needed to characterize mass fluxes per capita of contaminants in waters that directly receive discharges from OSSFs.

  • 222.
    Bläckberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Fysiologisk kemi.
    Fat digestion in the newborn infant: with special reference to the bile salt-stimulated lipase and the milk fat globule1981Doktoravhandling, med artikler (Annet vitenskapelig)
  • 223.
    Bo Hanh, Thi Bo
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Development of G-quadruplex stabilizing compounds identified through a High-Throughput Screen2017Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
  • 224. Bogel-Lukasik, Rafal
    Ionic Liquids in the Biorefinery Concept : Challenges and Perspectives: Challenges and Perspectives2015Bok (Fagfellevurdert)
    Abstract [en]

    This book summarises recent achievements in the use of ionic liquids in biomass processing as an alternative to conventional processes, particularly in the context of green chemistry. It features real-world case studies where high value-added products have been obtained using ionic liquid processing, demonstrating the practical applications of these technologies. The book is an important reference for researchers and practising chemists, bringing readers up-to-date with current research in this field.

  • 225. Bohlin, Pernilla
    et al.
    Jones, Kevin C
    Levin, Jan-Olof
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Lindahl, Roger
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Strandberg, Bo
    Field evaluation of a passive personal air sampler for screening of PAH exposure in workplaces2010Inngår i: Journal of Environmental Monitoring, ISSN 1464-0325, E-ISSN 1464-0333, Vol. 12, nr 7, s. 1437-1444Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    New sampling methods are needed to simplify and enable frequent monitoring of workers' exposure to polycyclic aromatic hydrocarbons (PAHs). The sampler needs to fulfil some key operational requirements for occupational exposure assessments: (i) be usable as a personal sampler; (ii) work over 8 h exposure time; (iii) sequester PAHs both in gas and particle phase, (iv) yield reliable estimates of air concentrations. Here, a new smaller design of the traditional polyurethane foam (PUF) passive air sampler (PAS) (i.e. a 'mini-PUF') was introduced and assessed against these requirements in sites with elevated PAH concentrations. The exposure times were 2 weeks and 8 hours. The obtained sampling rates (R-values) were not significantly different between gas phase (0.4-3.3 m(3) day(-1), 0.3-2.3 L min(-1)) and particle associated PAHs (0.5-1.9 m(3) day(-1), 0.4-1.3 L min(-1)). The accuracy in estimating air concentrations was within +/-25% from the active sampler for half of the PAHs for the mini-PUF under 8 h exposures. Significant correlations (p < 0.003) were found between personally deployed mini-PUFs and a co-deployed personal active sampling method. This together with the low costs and ease-of-use of the mini-PUF encourage application in exposure assessments.

  • 226.
    Boily, Jean-Francois
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Colloids2017Inngår i: Encyclopedia of geochemistry: a comprehensive reference source on the chemistry of the Earth / [ed] William M. White, Cham: Springer, 2017, s. 1-4Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 227.
    Boily, Jean-Francois
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Hydrothermal solutions2017Inngår i: Encyclopedia of geochemistry: a comprehensive reference source on the chemistry of the Earth / [ed] William M. White, Cham: Springer, 2017, s. 1-6Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 228.
    Boily, Jean-Francois
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Solubility2017Inngår i: Encyclopedia of geochemistry: a comprehensive reference source on the chemistry of the Earth / [ed] William M. White, Cham: Springer, 2017, s. 1-9Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 229.
    Boily, Jean-Francois
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    The Variable Capacitance Model: A Strategy for Treating Contrasting Charge-Neutralizing Capabilities of Counterions at the Mineral/Water Interface2014Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 30, nr 8, s. 2009-2018Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Thermodynamic models predicting ion adsorption at mineral/water interfaces can have limitations from the simplifying assumptions that compact plane thicknesses and capacitance values are constant, and that charge densities of electrolyte counterions of different charge-to-size ratios lie at the same planes of adsorption, or split between different planes. To address these limitations a thermodynamic adsorption modeling framework was developed to account for coexisting compact planes for each type of counterion complexes formed on a single mineral surface. This framework was developed to predict charge development at lepidocrocite (gamma-FeOOH) particle surfaces suspended in aqueous solutions of NaCl and NaClO4. The model incorporates properties of Cl-, ClO4-, and Na+ complexes formed at the (001) and (010) faces of this mineral obtained by molecular dynamics (MD) simulations. This concept was incorporated in a thermodynamic adsorption model that predicts an overall variable compact plane capacitance in terms of a linear combination of the capacitances of ion-specific EDL structures scaled for their relative surface loadings. These capacitance values are in turn constrained by compact plane thicknesses of every Cl-, ClO4-, and Na+ complex, based on their MD-derived structures and atomic densities. The model predicts experimental potential-determining (H+, OH-) data for submicrometer-sized synthetic lepidocrocite particles exhibiting both (001) and (010) faces. It also isolates electrostatic contributions from these faces. A computer code solving for this Variable Capacitance Model-VCM-is provided in the Supporting Information section of this article, and can be readily modified to predict molecular-level details of any other mineral/water interface systems using this methodology.

  • 230.
    Boily, Jean-Francois
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Water Structure and Hydrogen Bonding at Goethite/Water Interfaces: Implications for Proton Affinities2012Inngår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 116, nr 7, s. 4714-4724Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Molecular dynamics simulations of four crystallographic terminations of goethite (alpha-FeOOH) in contact with liquid water (300 K, 1 bar) were performed to resolve interfacial water structures in the vicinity of surface (hydr)oxo groups. Interfacial water molecules adopted highly surface-specific configurations on (010), 100), (110), and (021) planes of goethite. Water molecules generally had weaker hydrogen bond numbers and strengths, as well as smaller self-diffusion coefficients, than their bulk liquid counterparts. Relaxed surface Fe-O and H acceptor distances and populations were used to estimate proton affinity constants of singly-, and triply-coordinated (hydr)oxo groups using the multisite complexation model. These calculations confirmed that singly coordinated groups are mainly responsible for charge uptake under normal environmental conditions. However, revised proton affinity constants showed that protonation of doubly-coordinated hydroxo groups and one type of triply-coordinated oxo group may be favored in the presence of strongly binding negatively charged ligands. These calculations should facilitate elucidation of surface complexation mechanisms on this environmentally important material.

  • 231.
    Boily, Jean-Francois
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Fu, Li
    Tuladhar, Aashish
    Lu, Zhou
    Legg, Benjamin A.
    Wang, Zheming M.
    Wang, Hongfei
    Hydrogen bonding and molecular orientations across thin water films on sapphire2019Inngår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 555, s. 810-817Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hypothesis: Water vapor binding to metal oxide surfaces produces thin water films with properties controlled by interactions with surface hydroxo sites. Hydrogen bonding populations vary across films and induce different molecular orientations than at the surface of liquid water. Identifying these differences can open possibilities for tailoring film-mediated catalytic reactions by choice of the supporting metal oxide substrate.

    Experiments: The (0001) face of a single sapphire (α-Al2O3) sample exposed to water vapor and the surface of liquid water were probed by polarization dependent Sum Frequency Generation-Vibration Spectroscopy (SFG-VS). Molecular dynamics (MD) provided insight into the hydrogen bond populations and molecular orientations across films and liquid water.

    Findings: SFG-VS revealed a submonolayer film on sapphire exposed to 43% relative humidity (R.H.), and a multilayer film at 78% R.H. Polarization dependent SFG-VS spectra showed that median tilt angles of free OH bonds on the top of films are at ∼43° from the normal of the (0001) face but at 38° on neat liquid water. These values align with MD simulations, which also show that up to 36% of all OH bonds on films are free. This offers new means for understanding how interfacial reactions on sapphire-supported water films could contrast with those involving liquid water.

  • 232.
    Boily, Jean-Francois
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Kozin, Philipp A.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Particle Morphological and Roughness Controls on Mineral Surface Charge Development2014Inngår i: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 141, nr 15 September, s. 567-578Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    Effects of mineral particle morphology and roughness on potential determining ion (p.d.i.; H+, OH) loadings achieved at synthetic lepidocrocite (γ-FeOOH) surfaces were predominantly investigated by potentiometry and thermodynamic modeling. Nanosized rod- (RL) and lath-shaped (LL) particles exhibiting different proportions of the same predominant crystallographic faces acquired largely comparable pH, ionic strength and counterion (NaCl, NaClO4) dependencies on p.d.i. loadings. These results supported previous claims that faces ideally containing proton silent sites only, are likely populated by additional proton active sites. This concept was supported further by results of roughened LL-like particles (LLR) also showing highly congruent pH-, ionic strength- and composition-dependent p.d.i. loadings with those of LL and RL. These loadings thereby correspond to maximal levels allowed by net attractive and repulsive forces at each solution composition, irrespective of particle morphology. Contrasting equilibration times required to achieve these loadings revealed considerably slower exchange of p.d.i. and electrolyte ions near the point of zero charge in the rough LLR than in the more idealized LL and RL particles.

    Thermodynamic modeling was used to test various concepts accounting for these results. The model made use of a novel framework capable of isolating electrostatic contributions from different faces, and of accounting for ion-specific double-layer properties within a single crystallographic face. These efforts made use of capacitance values for each electrolyte ions within the framework of a recently developed Variable Capacitance Model. Attempts at modeling all three particle types were used to suggest that the (0 1 0) face contains ∼0.9 site nm−2 of proton active sites, a value notably constrained by recently published Na+, Cl, and ClO4 loadings derived by cryogenic X-ray photoelectron spectroscopy. The model presented in this work thus provides a means to predict p.d.i. loadings on multifaceted mineral particle surfaces, and can therefore be used to constrain further our understanding of mineral/water interface reactivity.

  • 233.
    Boily, Jean-Francois
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Lins, Roberto D
    Pacific Northwest National Laboratory, Richland Washington, USA .
    Electrostatic cooperativity of hydroxyl groups at metal oxide surfaces2009Inngår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 113, nr 38, s. 16568-16570Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The O−H bond distribution of hydroxyl groups at the {110} goethite (α-FeOOH) surface was investigated by molecular dynamics. This distribution was strongly affected by electrostatic interactions with neighboring oxo and hydroxo groups. The effects of proton surface loading, simulated by emplacing two protons at different distances of separation, were diverse and generated several sets of O−H bond distributions. DFT calculations of a representative molecular cluster were also carried out to demonstrate the impact of these effects on the orientation of oxygen lone pairs in neighboring oxo groups. These effects should have strong repercussions on O−H stretching vibrations of metal oxide surfaces.

  • 234.
    Boily, Jean-Francois
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Yesilbas, Merve
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Uddin, Munshi Md. Musleh
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Baiqing, Lu
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Trushkina, Yulia
    Salazar-Alvarez, German
    Thin Water Films at Multifaceted Hematite Particle Surfaces2015Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 31, nr 48, s. 13127-13137Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Mineral surfaces exposed to moist air stabilize nanometer- to micrometer-thick water films. This study resolves the nature of thin water film formation at multifaceted hematite (alpha-Fe2O3) nanoparticle surfaces with crystallographic faces resolved by selected area electron diffraction. Dynamic vapor adsorption (DVA) in the 0-19 Torr range at 298 K showed that these particles stabilize water films consisting of up to 4-5 monolayers. Modeling of these data predicts water loadings in terms of an "adsorption regime" (up to 16 H2O/nm(2)) involving direct water binding to hematite surface sites, and of a "condensation regime" (up to 34 H2O/nm(2)) involving water binding to hematite-bound water nanodusters. Vibration spectroscopy identified the predominant hematite surface hydroxo groups (-OH, mu-OH, mu(3)-OH) through which first layer water molecules formed hydrogen bonds, as well as surface iron sites directly coordinating water molecules (i.e., as geminal eta-(OH2)(2) sites). Chemometric analyses of the vibration spectra also revealed a strong correspondence in the response of hematite surface hydroxo groups to DVA-derived water loadings. These findings point to a near-saturation of the hydrogen-bonding environment of surface hydroxo groups at a partial water vapor pressure of similar to 8 Torr (similar to 40% relative humidity). Classical molecular dynamics (MD) resolved the interfacial water structures and hydrogen bonding populations at five representative crystallographic faces expressed in these nanoparticles. Simulations of single oriented slabs underscored the individual roles of all (hydro)oxo groups in donating and accepting hydrogen bonds with first layer water in the "adsorption regime". These analyses pointed to the preponderance of hydrogen bond-donating -OH groups in the stabilization of thin water films. Contributions of mu-OH and mu(3)-OH groups are secondary, yet remain essential in the stabilization of thin water films. MD simulations also helped resolve crystallographic controls on water water interactions occurring in the "condensation regime". Water water hydrogen bond populations are greatest on the (001) face, and decrease in importance in the order (001) > (012) approximate to (110) > (014) >> (100). Simulations of a single (similar to 5 nm x similar to 6 nm x similar to 6 nm) nanometric hematite particle terminated by the (001), (110), (012), and (100) faces also highlighted the key roles that sites at particle edges play in interconnecting thin water films grown along contiguous crystallographic faces. Hydroxo water hydrogen bond populations showed that edges were the preferential loci of binding. These simulations also suggested that equilibration times for water binding at edges were slower than on crystallographic faces. In this regard, edges, and by extension roughened surfaces, are expected to play commanding roles in the stabilization of thin water films. Thus, in focusing on the properties of nanometric-thick water layers at hematite surfaces, this study revealed the nature of interactions between water and multifaced particle surfaces. Our results pave the way for furthering our understanding of mineral-thin water film interfacial structure and reactivity on a broader range of materials.

  • 235.
    Boily, Jean-François
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Chatman, Shawn
    Rosso, Kevin M
    Inner-Helmholtz potential development at the hematite (α-Fe2O3) (0 0 1) surface2011Inngår i: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 75, nr 15, s. 4113-4124Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electric potentials of the (0 0 1) surface of hematite were measured as a function of pH and ionic strength in solutions of sodium nitrate and oxalic acid using the single-crystal electrode approach. The surface is predominantly charge-neutral in the pH 4–14 range, and develops a positive surface potential below pH 4 due to protonation of μ-OH0 sites (pK1,1,0,int = −1.32). This site is resilient to deprotonation up to at least pH 14 (−pK−1,1,0,int ≫ 19). The associated Stern layer capacitance of 0.31–0.73 F/m2 is smaller than typical values of powders, and possibly arises from a lower degree of surface solvation. Acid-promoted dissolution under elevated concentrations of HNO3 etches the (0 0 1) surface, yielding a convoluted surface populated by sites. The resulting surface potential was therefore larger under these conditions than in the absence of dissolution. Oxalate ions also promoted (0 0 1) dissolution. Associated electric potentials were strongly negative, with values as large as −0.5 V, possibly from metal-bonded interactions with oxalate. The hematite surface can also acquire negative potentials in the pH 7–11 range due to surface complexation and/or precipitation of iron species (0.0038 Fe/nm2) produced from acidic conditions. Oxalate-bearing systems also result in negative potentials in the same pH range, and may include ferric-oxalate surface complexes and/or surface precipitates. All measurements can be modeled by a thermodynamic model that can be used to predict inner-Helmholtz potentials of hematite surfaces.

  • 236.
    Bokvist, Marcus
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Kemi.
    Membrane mediated aggregation of amyloid-β protein: a potential key event in Alzheimer's disease2007Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The pathogenesis of Alzheimer’s disease (AD), the most common senile dementia, is a complex process. A crucial event in AD is the aggregation of amyloid-β protein (Aβ), a cleavage product from the Amyloid Precursor Protein (APP). Aβ40, a common component in amyloid plaques found in patients, aggregates in vitro at concentrations, much higher than the one found in vivo. But in the presence of charged lipid membranes, aggregations occurs at much lower concentration in vitro compared to the membrane-free case. This can be understood due to the ability of Aβ to get electrostatically attracted to target membranes with a pronounced surface potential. This electrostatically driven process accumulates peptide at the membrane surface at concentrations high enough for aggregation while the bulk concentration still remains below threshold. Here, we elucidated the molecular nature of this Aβ-membrane process and its consequences for Aβ misfolding by Circular Dichroism Spectroscopy, Differential Scanning Calorimetry and Nuclear Magnetic Resonance Spectroscopy. First, we revealed by NMR that Aβ40 peptide does indeed interact electrostatically with membranes of negative and positive surface potential. Surprisingly, it even binds to nominal neutral membranes if these contain lipids of opposite charge. Combined NMR and CD studies also revealed that the peptide might be shielded from aggregation when incorporated into the membrane. Moreover, CD studies of Aβ40 added to charged membranes showed that both positively and negatively membranes induce aggregation albeit at different kinetics and finally that macromolecular crowding can both speed up and slow down aggregation of Aβ.

  • 237.
    Bokvist, Marcus
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Gröbner, Gerhard
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Misfolding of amyloidogenic proteins at membrane surfaces:  the impact of macromolecularcCrowding2007Inngår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 129, nr 48, s. 14848-14849Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The presence of inert macromolecular crowding agents mimics the situation in vivo where amyloidogenic proteins are released into an aqueous, congested intracellular environment. By using the amphiphatic Alzheimer A-protein as the model system, the presence of a three-dimensional macromolecular crowding environment enhanced significantly its misfolding behavior if charged membrane surfaces as two-dimensional aggregation templates were present.

  • 238.
    Bolivar, Juan M
    et al.
    Departamento de Biocatálisis, Instituto de Catálisis y Petroleoquímica-CSIC, Cantoblanco, Madrid, Spain.
    Rocha-Martin, Javier
    Departamento de Biocatálisis, Instituto de Catálisis y Petroleoquímica-CSIC, Cantoblanco, Madrid, Spain.
    Mateo, Cesar
    Departamento de Biocatálisis, Instituto de Catálisis y Petroleoquímica-CSIC, Cantoblanco, Madrid, Spain.
    Cava, Felipe
    CBM ‘Severo Ochoa’ CSIC-UAM, Madrid, Spain.
    Berenguer, Jose
    CBM ‘Severo Ochoa’ CSIC-UAM, Madrid, Spain.
    Fernandez-Lafuente, Roberto
    Departamento de Biocatálisis, Instituto de Catálisis y Petroleoquímica-CSIC, Cantoblanco, Madrid, Spain.
    Guisan, Jose M
    Departamento de Biocatálisis, Instituto de Catálisis y Petroleoquímica-CSIC, Cantoblanco, Madrid, Spain.
    Coating of soluble and immobilized enzymes with ionic polymers: full stabilization of the quaternary structure of multimeric enzymes2009Inngår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 10, nr 4, s. 742-747Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper shows a simple and effective way to avoid the dissociation of multimeric enzymes by coating their surface with a large cationic polymer (e.g., polyethylenimine (PEI)) by ionic exchange. As model enzymes, glutamate dehydrogenase (GDH) from Thermus thermophilus and formate dehydrogenase (FDH) from Pseudomonas sp. were used. Both enzymes are very unstable at acidic pH values due to the rapid dissociation of their subunits (half-life of diluted preparations is few minutes at pH 4 and 25 degrees C). GDH and FDH were incubated in the presence of PEI yielding an enzyme-PEI composite with full activity. To stabilize the enzyme-polymer composite, a treatment with glutaraldehyde was required. These enzyme-PEI composites can be crosslinked with glutaraldehyde by immobilizing previously the composite onto a weak cationic exchanger. The soluble GDH-PEI composite was much more stable than unmodified GDH at pH 4 and 30 degrees C (retaining over 90% activity after 24 h incubation) with no effect of the GDH concentration in the inactivation course. The composite could be very strongly, but reversibly, adsorbed on cationic exchangers. Similarly, FDH could be treated with PEI and glutaraldehyde after adsorption on cationic exchangers, This permitted a stabilized FDH preparation. In this way, the coating of the enzymes surfaces with PEI is used as a simple and efficient strategy to prevent enzyme dissociation of multimeric enzymes. These composites can be used as a soluble catalyst or reversibly immobilized onto a cationic exchanger (e.g., CM-agarose).

  • 239.
    Boman, Christoffer
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Tillämpad fysik och elektronik.
    Particulate and gaseous emissions from residential biomass combustion2005Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Biomass is considered to be a sustainable energy source with significant potentials for replacing electricity and fossil fuels, not at least in the residential sector. However, present wood combustion is a major source of ambient concentrations of hydrocarbons (e.g. VOC and PAH) and particulate matter (PM) and exposure to these pollutants have been associated with adverse health effects. Increased focus on combustion related particulate emissions has been seen concerning the formation, characteristics and implications to human health. Upgraded biomass fuels (e.g. pellets) provide possibilities of more controlled and optimized combustion with less emission of products of incomplete combustion (PIC´s). For air quality and health impact assessments, regulatory standards and evaluations concerning residential biomass combustion, there is still a need for detailed emission characterization and quantification when using different fuels and combustion techniques.

    This thesis summarizes the results from seven different papers. The overall objective was to carefully and systematically study the emissions from residential biomass combustion with respect to: i) experimental characterization and quantification, ii) influences of fuel, appliance and operational variables and iii) aspects of ash and trace element transformations and aerosol formation. Special concern in the work was on sampling, quantification and characterization of particulate emissions using different appliances, fuels and operating procedures.

    An initial review of health effects showed epidemiological evidence of potential adverse effect from wood smoke exposure. A robust whole flow dilution sampling set-up for residential biomass appliances was then designed, constructed and evaluated, and subsequently used in the following emission studies. Extensive quantifications and characterizations of particulate and gases emissions were performed for residential wood and pellet appliances. Emission factor ranges for different stoves were determined with variations in fuel, appliance and operational properties. The emissions of PIC´s as well as PMtot from wood combustion were in general shown to be considerably higher compared to pellets combustion. PAHtot emissions were determined in the range of 1300-220000 µg/MJ for wood stoves and 2-300 µg/MJ for pellet stoves with phenantrene, fluoranthene and pyrene generally found as major PAH´s. The PM emissions from present residential appliances was found to consist of significant but varying fractions of PIC´s, with emissions in the range 35-350 mg/MJ for wood stoves compared to 15-45 mg/MJ for pellet stoves. Accordingly, the use of up-graded biomass fuels, combusted under continuous and controlled conditions give advantageous combustion conditions compared to traditional batch wise firing of wood logs. The importance of high temperature in well mixed isothermal conditions was further illustrated during pellets combustion to obtain complete combustion with almost a total depletion of PIC´s. Fine (100-300 nm) particles dominated in all studied cases the PM with 80-95% as PM1. Beside varying fractions of carbonaceous material, the fine PM consisted of inorganic volatilized ash elements, mainly found as KCl, K3Na(SO4)2 and K2SO4 with mass concentrations at 15-20 mg/MJ during complete combustion. The importance of the behavior of alkali elements for the ash transformation and fine particle formation processes was further shown, since the stability, distributions and compositions also directly control the degree of volatilization. In addition to the alkali metals, zinc was found as an important element in fine particles from residential biomass combustion. Finally, the behaviour of volatile trace elements, e.g. Zn and Cd, during pellets production and combustion were studied. A significant enrichment in the pellet fuel during the drying process was determined. The magnitude and importance of the enrichment was, however, relative small and some alternative measures for prevention were also suggested.

  • 240.
    Boman, Christoffer
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Broström, Markus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Skoglund, Nils
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Schmidt, Florian M.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Backman, Rainer
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Boström, Dan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Ash transformation chemistry in biomass fixed beds with focus on slagging and aerosols: 20 years of research and new developments2017Inngår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 254Artikkel i tidsskrift (Annet vitenskapelig)
  • 241. Borah, Raju Kumar
    et al.
    Raul, Prasanta Kumar
    Mahanta, Abhijit
    Shchukarev, Andrey
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Mikkola, Jyri-Pekka
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Industrial Chemistry & Reaction Engineering, Åbo Akademi University, Åbo-Turku, Finland.
    Thakur, Ashim Jyoti
    Copper Oxide Nanoparticles as a Mild and Efficient Catalyst for N-Arylation of Imidazole and Aniline with Boronic Acids at Room Temperature2017Inngår i: Synlett: Accounts and Rapid Communications in Synthetic Organic Chemistry, ISSN 0936-5214, E-ISSN 1437-2096, Vol. 28, nr 10, s. 1177-1182Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The present work describes the excellent catalytic activity of copper(II) oxide nanoparticles (NPs) towards N-arylation of aniline and imidazole at room temperature. The copper(II) oxide NPs were synthesized by a thermal refluxing technique and characterized by FT-IR spectroscopy; powder XRD, SEM, EDX, TEM, TGA, XPS, BET surface area analysis, and particle size analysis. The size of the NPs was found to be around 12 nm having a surface area of 164.180 m(2) g(-1). The catalytic system was also found to be recyclable and could be reused in subsequent catalytic runs without a significant loss of activity.

  • 242.
    Boström, Dan
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Bergquist, G
    Pettersson, Lage
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Sodium trirubidium metavanadate monohydrate2003Inngår i: Acta Crystallographica Section E: Structure Reports Online, ISSN 1600-5368, E-ISSN 1600-5368, Vol. E59, nr 11, s. i151-i153Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The title compound, sodium trirubidium metavanadate monohydrate, NaRb3(VO3)4(H2O), crystallizes in the orthorhombic space group Pnma. The structure, which represents a rare type of catena-vanadate, is built up of strongly folded chains of corner-sharing [VO4] tetrahedra, running in the [010] direction with a periodicity of four. A three-dimensional framework is obtained by sodium ions linking adjacent chains in the [001] direction and by rubidium ions linking adjacent chains in the [100] direction. The single water molecule binds to the sodium ion and to two rubidium ions.

  • 243.
    Boström, Dan
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik, Energiteknik och termisk processkemi.
    Broström, Markus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik, Energiteknik och termisk processkemi.
    Skoglund, Nils
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik, Energiteknik och termisk processkemi.
    Boman, Christoffer
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik, Energiteknik och termisk processkemi.
    Backman, Rainer
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik, Energiteknik och termisk processkemi.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Grimm, Alejandro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Ash transformation chemistry during energy conversion of biomass2010Inngår i: Impacts of Fuel Quality on Power Production & Environment: 29/08/2010 - 03/09/2010, Impacts of Fuel Quality , 2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    There is relatively extensive knowledge available concerning ash transformation reactions during energy conversion of woody biomass. Traditionally, these assortments have constituted the main resources for heating in Sweden. In recent decades the utilization of these energy carriers has increased, from a low technology residential small scale level to industrial scale (e.g. CHP plants). Along this evolution ash-chemical related phenomena for woody biomass has been observed and studied. So, presently the understanding for these are, if not complete, fairly good. Briefly, from a chemical point of view the ash from woody biomass could be characterized as a silicate dominated systems with varying content of basic oxides and with relatively high degree of volatilization of alkali sulfates and chlorides. Thus, the main ash transformation mechanisms in these systems have been outlined. Here, an attempt to give a general description of the ash transformation reactions of biomass fuels is presented, with the intention to provide guidance in the understanding of ash matter behavior in the utilization of any biomass fuel, primarily from knowledge of the concentrations of ash forming elements but also by considering the physical condition in the specific combustion appliance and the physical characteristic of the biomass fuel. Furthermore, since the demand for CO2-neutral energy resources has increased the last years and will continue to do so in the foreseeable future, other biomasses as for instance agricultural crops has become highly interesting. Globally, the availability of these shows large variation. In Sweden, for instance, which is a relatively spare populated country with large forests, these bio-masses will play a secondary role, although not insignificant. In other parts of the world, more densely populated and with a large agricultural sector, such bio-masses may constitute the main energy bio-mass resource in the future. However, the content of ash forming matter in agricultural bio-mass is rather different in comparison to woody biomass. Firstly, the content is much higher; from being about 0.3 – 0.5% (wt) in stem wood, it can amount to between 2 and 10 %(wt) in agricultural biomass. In addition, the composition of the ash forming matter is different. Shortly, the main difference is due to a much higher content of phosphorus (occasionally also silicon) which has major consequences on the ash-transformation reactions. In many crops, the concentration of phosphorus and silicon is equivalent, which (depending on the concentration levels of basic oxides) may result in a phosphate dominated ash. The properties of this ash are in several aspects different from the silicate dominated woody biomass ash and will consequently behave differently in various types of energy conversion systems. The knowledge about phosphate dominated ash systems has so far been scarce. We have been working with these systems, both with basic and applied research, for about a decade know. Some general experiences and conclusions as well as some specific examples of our research will be presented.

  • 244.
    Boström, Dan
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Clausén, Maria
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Sandström, Malin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Hexakis(dimethyl sulfoxide-kappa O)aluminium(III) trichloride2003Inngår i: Acta Crystallographica Section E: Structure Reports Online, ISSN 1600-5368, E-ISSN 1600-5368, Vol. 59, s. M934-M935Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The title compound, [Al{(CH3)(2)SO}(6)]Cl-3, crystallizes in the trigonal space group R(3) over bar. In this structure, the O atoms of six dimethyl sulfoxide (DMSO) molecules are bonded to the Al3+ ion in the form of a trigonally distorted octahedron. The Al3+ ion is situated at special site 3b (symmetry (3) over bar), while the Cl- ions are situated at special sites 3a and 6c (symmetries (3) over bar and 3). Considering only the Al3+ ions separately, they are arranged in a slightly distorted cubic close-packed arrangement. In this crystal structure, the Cl- ions occupy both the tetrahedral sites and the octahedral sites, giving a Cl-:Al3+ ratio of 3:1. This geometric condition results in a distorted rhombododecahedral arrangement of Cl- ions around the Al3+ ions.

  • 245.
    Boström, Dan
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik, Energiteknik och termisk processkemi.
    Eriksson, Gunnar
    Division of Energy Engineering, Department of Applied Physics and Mechanical Engineering, Luleå Technical University.
    Boman, Christoffer
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Öhman, Marcus
    Division of Energy Engineering, Department of Applied Physics and Mechanical Engineering, Luleå Technical University.
    Ash transformations in fluidized-bed combustion of rapeseed meal2009Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 23, nr 5, s. 2700-2706Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The global production of rapeoil is increasing. A byproduct is rapeseed meal that is a result of the oil extraction process. Presently the rapeseed meal mainly is utilized as animal feed. An interesting alternative use is, however, energy conversion by combustion. This study was undertaken to determine the combustion properties of rapeseed meal and bark mixtures in a bubbling fluidized bed, with emphasis on gas emissions, ash formation, -fractionation and -interaction with the bed material. Due to the high content of phosphorus in rapeseed meal the fuel ash is dominated by phosphates, in contrast to most woody biomass where the ash is dominated by silicates. From a fluidized bed combustion (FBC) point of view, rapeseed meal could be a suitable fuel. Considering FBC agglomeration effects, pure rapeseed meal is in level with the most suitable fuels, as earlier tested by the methods utilized in the present investigation. The SO2 emission, however, is higher than most woody biomass fuels as a direct consequence of the high levels of sulfur in the fuel. Also the particulate matter emission, both submicron and coarser particles, is higher. Again this can be attributed the high ash content of rapeseed meal. The high abundance of SO2 is apparently effective for sulfatization of KCl in the flue gas. Practically no KCl was observed in the particulate matter of the flue gas. A striking difference in the mechanisms of bed agglomeration for rapeseed meal compared to woody biomass fuels was also observed. The ubiquitous continuous layers on the bed grains found in FBC combustion of woody biomass fuels was not observed in the present investigation. Instead very thin and discontinuous layers were observed together with isolated partly melted bed ash particles. The latter could occasionally be seen as adhered to the quartz bed grains. Apparently the bed agglomeration mechanism, that obviously demanded rather high temperatures, involved more of adhesion by partly melted ash derived potassium -calcium phosphate bed ash particles/droplets than direct attack of gaseous alkali on the quartz bed grains forming potassium -calcium silicate rich bed grain layers. Am explanation could be found in the considerable higher affinity for base cations of phosphorus than silicon. This will to a great extent withdraw the present basic oxides from attacking the quartz bed grains with agglomeration at low temperatures as a result.

  • 246.
    Boström, Dan
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Skoglund, Nils
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Boman, Christoffer
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Öhman, Marcus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Broström, Markus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Backman, Rainer
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Ash transformation chemistry during combustion of biomass, theory and technical applications2017Inngår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 254Artikkel i tidsskrift (Annet vitenskapelig)
  • 247.
    Boström, Dan
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten.
    Strandberg, R
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten.
    Norén, B
    Oskarsson, Å
    CIS-Trans Influences on Square-Planar Platinum(II) Complexes: Structure of CIS-BIS (Dimethyl Sulfoxide) Dinitratoplatinum (II)1991Inngår i: Acta Crystallographica Section C: Crystal Structure Communications, ISSN 0108-2701, E-ISSN 1600-5759, Vol. 47, s. 2101-2104Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    cis-[Pt{(CH3)2SO}2(NO3)2], M(r) = 475.36, monoclinic, P2(1)/c, a = 9.006 (1), b = 14.209 (2), c = 10.908 (2) angstrom, beta = 117.88 (1)-degrees, V = 1233.9 (2) angstrom 3, Z = 4, D(x) = 2.559 Mg m-3, lambda(Mo K-alpha)BAR = 0.7107 angstrom, mu = 11.84 mm-1, F(000) = 896, T = 293 K, R = 0.033 for 1763 unique reflections [I > 3-sigma(I)]. The Pt atom coordinates two S atoms from two dimethyl sulfoxide ligands and two O atoms from different nitrate ions in a slightly distorted square-planar geometry (maximal deviation 0.10 angstrom) in a cis arrangement. The compound consists of van der Waals packed molecules appearing in pairs with a Pt-Pt distance of 4.008 (1) angstrom. The acceptor-donor distances observed are: Pt-S = 2.214 (3), 2.220 (3) and Pt-O = 2.040 (9), 2.059 (9) angstrom. These are almost the same as the corresponding ones previously found in tetrakis(dimethyl sulfoxide)platinum(II) bis(trifluoromethanesulfonate) where two dimethyl sulfoxide ligands bond to Pt via their O atoms, also in a cis position. A literature survey of platinum dimethyl sulfoxide compounds shows that the Pt-S distance is significantly affected by both cis and trans influences.

  • 248.
    Bouchet, Sylvain
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Björn, Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Analytical developments for the determination of monomethylmercury complexes with low molecular mass thiols by reverse phase liquid chromatography hyphenated to inductively coupled plasma mass spectrometry2014Inngår i: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1339, s. 50-58Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The behavior of monomethylmercury (MMHg) is markedly influenced by its distribution among complexes with low molecular mass (LMM) thiols but analytical methodologies dedicated to measure such complexes are very scarce up to date. In this work, we selected 15 LMM thiols often encountered in living organisms and/or in the environment and evaluated the separation of the 15 corresponding MMHg-thiol complexes by various high performance liquid chromatography (HPLC) columns. Two C18 (Phenomenex Synergi Hydro-RP and LunaC18(2)), two phenyl (Inertsil Ph 3 and 5 mu m) and one mixed-mode (Restek Ultra IBD) stationary phases were tested for their retention and resolution capacities of the various complexes. The objective was to find simple separation conditions with low organic contents in the mobile phase to provide optimal conditions for detection by inductively coupled plasma mass spectrometry (ICPMS). The 15 complexes were synthesized in solution and characterized by electrospray ionization-mass spectrometry (ESI-MS). The C18 columns tested were either not resolutive enough or too retentive. The 3 pm phenyl stationary phase was able to resolve 10 out of the 15 complexes in less than 25 min, under isocratic conditions. The mixed-mode column was especially effective at separating the most hydrophilic complexes (6 complexes out of the 15), corresponding to the main LMM thiols found in living organisms. The detection limits (DLs) for these two columns were in the low nanomolar range and overall slightly better for the phenyl column. The possibilities offered by such methodology were exemplified by monitoring the time-course concentrations of four MMHg-thiol complexes within a phytoplankton incubation containing MMHg in the presence of an excess of four added thiols. 

  • 249.
    Boulanger, Nicolas
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Yu, Victor
    Hilke, Michael
    Toney, Michael F.
    Barbero, David R.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Graphene induced electrical percolation enables more efficient charge transport at a hybrid organic semiconductor/graphene interface2018Inngår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 20, nr 6, s. 4422-4428Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Self-assembly of semiconducting polymer chains during crystallization from a liquid or melt dictates to a large degree the electronic properties of the resulting solid film. However, it is still unclear how charge transport pathways are created during crystallization. Here, we performed complementary in situ electrical measurements and synchrotron grazing incidence X-ray diffraction (GIXD), during slow cooling from the melt of highly regio-regular poly(3-hexylthiophene) (P3HT) films deposited on both graphene and on silicon. Two different charge transport mechanisms were identified, and were correlated to the difference in crystallites' orientations and overall amount of crystallites in the films on each surface as molecular self-assembly proceeded. On silicon, a weak charge transport was enabled as soon as the first edge-on lamellae formed, and further increased with the higher amount of crystallites (predominantly edge-on and randomly oriented lamellae) during cooling. On graphene however, the current remained low until a minimum amount of crystallites was reached, at which point interconnection of conducting units (face-on, randomly oriented lamellae and tie-chains) formed percolated conducting pathways across the film. This lead to a sudden rapid increase in current by approximate to 10 fold, and strongly enhanced charge transport, despite a much lower amount of crystallites than on silicon.

  • 250.
    Boulanger, Nicolas
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Nano-Engineered Materials and Organic Electronics Laboratory.
    Yu, Victor
    Hilke, Michael
    Toney, Michael F.
    Barbero, David R.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen. Nano-Engineered Materials and Organic Electronics Laboratory.
    In situ probing of the crystallization kinetics of rr-P3HT on single layer graphene as a function of temperature2017Inngår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 19, nr 12, s. 8496-8503Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We studied the molecular packing and crystallization of a highly regio-regular semiconducting polymer poly(3-hexylthiophene) (P3HT) on both single layer graphene and silicon as a function of temperature, during cooling from the melt. The onset of crystallization, crystallites' size, orientation, and kinetics of formation were measured in situ by synchrotron grazing incidence X-ray diffraction (GIXD) during cooling and revealed a very different crystallization process on each surface. A favored crystalline orientation with out of plane pi-pi stacking formed at a temperature of 200 degrees C on graphene, whereas the first crystallites formed with an edge-on orientation at 185 degrees C on silicon. The crystallization of face-on lamellae revealed two surprising effects during cooling: (a) a constant low value of the pi-pi spacing below 60 degrees C; and (b) a reduction by half in the coherence length of face-on lamellae from 100 to 30 degrees C, which corresponded with the weakening of the 2nd or 3rd order of the in-plane (k00) diffraction peak. The final ratio of face-on to edge-on orientations was 40% on graphene, and 2% on silicon, revealing the very different crystallization mechanisms. These results provide a better understanding of how surfaces with different chemistries and intermolecular interactions with the polythiophene polymer chains lead to different crystallization processes and crystallites orientations for specific electronic applications.

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