| 1. |
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| 2. |
- Kehoe, Laura, et al.
(författare)
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Make EU trade with Brazil sustainable
- 2019
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 364:6438, s. 341-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 3. |
- Persson, Ingmar, et al.
(författare)
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An EXAFS Spectroscopic, Large Angle X-Ray Scattering and Crystallo¬graphic Study of the Hexahydrated and the Dimethyl Sulfoxide and Pyridine-1-Oxide Hexasolvated Mercury(II) Ions
- 2008
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Ingår i: Chemistry, A European Journal. ; 14, s. 6687-6696
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- The structure of the solvated mercury(II) ion in aqueous and dimethyl sulfoxide solution has been studied by means of large angle X-ray scattering (LAXS) and EXAFS tech¬niques. The distribution of the Hg-O bond distances is unusually wide and asymmetric in both solvents. In aqueous solution hexahydrated [Hg(OH2)6]2+ ions in distorted octahedral configuration, with the centroid of the Hg-O bond distances at 2.38(1) Å, are surrounded by a diffuse second hydration sphere, with HgOII distances around a mean value of 4.20(2) Å. In dimethyl sulfoxide solution the six Hg-O and HgS distances of the hexasolvated Hg(OS(CH3)2)6]2+ complex are centered around 2.38(1) and 3.45(2) Å, respectively. The crystal structure of hexakis¬(pyridine-1-oxide)mercury(II) perchlorate has been re-determi¬ned at 100 K. The space group R implies six equal Hg-O bond distances of 2.3416(7) Å for the Hg(ONC5H5)62+ complex, as also for the hexaaquamercury(II) perchlorate and hexakis(dimethyl sulfoxide)mercury(II) trifluoro¬methanesulfonate compounds, according to previous crystallographic results. However, EXAFS results for those compounds in all cases reveal strongly asymmetric Hg-O bond distance distributions. Vibronic coupling of close valence states in a so-called Pseudo Jahn-Teller Effect probably induces the distorted configurations.
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| 4. |
- Persson, Ingmar, et al.
(författare)
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An EXAFS Spectroscopic, Large-Angle X-Ray Scattering, and Crystallographic Study of Hexahydrated, Dimethyl Sulfoxide and Pyridine 1-Oxide Hexasolvated Mercury(II) Ions
- 2008
-
Ingår i: Chemistry - A European Journal. - : Wiley-VCH Verlagsgesellschaft. - 0947-6539 .- 1521-3765. ; 14:22, s. 6687-6696
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Tidskriftsartikel (refereegranskat)abstract
- The structure of the solvated mercury(II) ion in water and dimethyl sulfoxide has been studied by means of large‐angle X‐ray scattering (LAXS) and extended X‐ray absorption fine structure (EXAFS) techniques. The distribution of the HgO distances is unusually wide and asymmetric in both solvents. In aqueous solution, hexahydrated [Hg(OH2)6]2+ ions in a distorted octahedral configuration, with the centroid of the HgO distance at 2.38(1) Å, are surrounded by a diffuse second hydration sphere with Hg⋅⋅⋅OII distances of 4.20(2) Å. In dimethyl sulfoxide, the six HgO and Hg⋅⋅⋅S distances of the hexasolvated [Hg{OS(CH3)2}6]2+ complex are centered around 2.38(1) and 3.45(2) Å, respectively. The crystal structure of hexakis(pyridine 1‐oxide)mercury(II) perchlorate has been redetermined. The space group R implies six equal HgO distances of 2.3416(7) Å for the [Hg(ONC5H5)6]2+ complex at 100 K. However, EXAFS studies of this compound, and of the solids hexaaquamercury(II) perchlorate and hexakis(dimethyl sulfoxide)mercury(II) trifluoromethanesulfonate, also with six equidistant HgO bonds according to crystallographic results, reveal in all cases strongly asymmetric HgO distance distributions. Vibronic coupling of valence states in a so‐called pseudo‐Jahn–Teller effect probably induces the distorted configurations.
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| 5. |
- Yuan, Ning, et al.
(författare)
-
In situ XAS study of the local structure and oxidation state evolution of palladium in a reduced graphene oxide supported Pd(ii) carbene complex during an undirected C-H acetoxylation reaction
- 2019
-
Ingår i: Catalysis Science and Technology. - : Royal Society of Chemistry (RSC). - 2044-4753 .- 2044-4761. ; 9:8, s. 2025-2031
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Tidskriftsartikel (refereegranskat)abstract
- In situ X-ray absorption spectroscopy (XAS) investigations have been performed to provide insights into the reaction mechanism of a palladium(ii) catalyzed undirected C-H acetoxylation reaction in the presence of an oxidant. A Pd(ii) N-heterocyclic carbene complex π-stacked onto reduced graphene oxide (rGO) was used as the catalyst. The Pd speciation during the catalytic process was examined by XAS, which revealed a possible mechanism over the course of the reaction. Pd(ii) complexes in the as-synthesized catalyst first go through a gradual ligand substitution where chloride ions bound to Pd(ii) are replaced by other ligands with a mean bond distance to Pd matching Pd-C/N/O. Parallel to this the mean oxidation state of Pd increases indicating the formation of Pd(iv) species. At a later stage, a fraction of the Pd complexes start to slowly transform into Pd nanoclusters. The mean average oxidation state of Pd decreases to the initial state at the end of the experiment which means that comparable amounts of Pd(0) and Pd(iv) are present. These observations from heterogeneous catalysis are in good agreement with its homogeneous analog and they support a Pd(ii)-Pd(iv)-Pd(ii) reaction mechanism.
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| 6. |
- Yuan, Ning, et al.
(författare)
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In Situ XAS Study of the Local Structure and Oxidation State Evolutions of Palladium in a Reduced Graphene Oxide Supported Pd(II) Carbene Complex during an Undirected C−H Acetoxylation Reaction
- 2019
-
Ingår i: Catalysis Science & Technology. - 2044-4753 .- 2044-4761. ; 9:8, s. 2025-2031
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Tidskriftsartikel (refereegranskat)abstract
- In situ X-ray absorption spectroscopy (XAS) investigations have been performed to provide insights into the reaction mechanism of a palladium(II) catalyzed undirected C–H acetoxylation reaction in the presence of an oxidant. A Pd(II) N-heterocyclic carbene complex p-stacked onto reduced graphene oxide (rGO) was used as catalyst. The Pd speciation during the catalytic process was examined by XAS, which revealed a possible mechanism over the course of the reaction. Pd(II) complexes in the as-synthesized catalyst first go through a gradual ligand substitution where chloride ions bound to Pd(II) are replaced by other ligands with a bond distance to Pd corresponding to carbon, nitrogen and/or oxygen (L). Parallel to this the mean oxidation state of Pd increases indicating the formation of Pd(IV) species. At a later stage, a fraction of the Pd complexes start to slowly transform into Pd nanoclusters. The mean average oxidation state of Pd decreases to the initial state at the end of the experiment which means that comparable amounts of Pd(0) and Pd(IV) are present. These observations from heterogeneous catalysis are in good agreement with its homogeneous analog and they support a Pd(II)-Pd(IV)-Pd(II) reaction mechanism.
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| 7. |
- Abbasi, Alireza, et al.
(författare)
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Crystallographic and Vibrational Spectroscopic Studies of Octakis(dimethyl sulfoxide)lanthanoid(III) Iodides
- 2007
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 46:19, s. 7731-7741
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Tidskriftsartikel (refereegranskat)abstract
- The octakis(DMSO) (DMSO = dimethylsulfoxide) neodymium(III), samarium(III), gadolinium(III), dysprosium(III), erbium(III), and lutetium(III) iodides crystallize in the monoclinic space group P21/n (No. 14) with Z = 4, while the octakis(DMSO) iodides of the larger lanthanum(III), cerium(III), and praseodymium(III) ions crystallize in the orthorhombic space group Pbca (No. 61), Z = 8. In all [Ln(OS(Me2)8]I3 compounds the lanthanoid(III) ions coordinate eight DMSO oxygen atoms in a distorted square antiprism. Up to three of the DMSO ligands were found to be disordered and were described by two alternative configurations related by a twist around the metal−oxygen (Ln−O) bond. To resolve the atomic positions and achieve reliable Ln−O bond distances, complete semirigid DMSO molecules with restrained geometry and partial occupancy were refined for the alternative sites. This disorder model was also applied on previously collected data for the monoclinic octakis(DMSO)yttrium(III) iodide. At ambient temperature, the eight Ln−O bond distances are distributed over a range of about 0.1 Å. The average value increases from Ln−O 2.30, 2.34, 2.34, 2.36, 2.38, 2.40 to 2.43 Å (Ln = Lu, Er, Y, Dy, Gd, Sm, and Nd) for the monoclinic [Ln(OSMe2)8]I3 structures, and from 2.44, 2.47 to 2.49 Å (Ln = Pr, Ce, and La) for the orthorhombic structures, respectively. The average of the La−O and Nd−O bond distances remained unchanged at 100 K, 2.49 and 2.43 Å, respectively. Despite longer bond distances and larger Ln−O−S angles, the cell volumes are smaller for the orthorhombic structures (Ln = Pr, Ce, and La) than for the monoclinic structure with Ln = Nd, showing a more efficient packing arrangement. Raman and IR absorption spectra for the [Ln(OS(CH3)2)8]I3 (Ln = La, Ce, Pr, Nd, Gd, Tb, Dy, Er, Lu, and Y) compounds, also deuterated for La and Y, have been recorded and analyzed by means of normal coordinate methods. The force constants for the Ln−O and S−O stretching modes in the complexes increase with decreasing Ln−O bond distance and show increasing polarization of the bonds for the smaller and heavier lanthanoid(III) ions.
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| 8. |
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| 9. |
- Abbasi, Alireza, et al.
(författare)
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Highly hydrated cations : Deficiency, mobility and coordination of water in crystalline nonahydrated scandium(III), yttrium(III) and lanthanoid(III) trifluoromethanesulfonate
- 2005
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Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 11:14, s. 4065-4077
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Tidskriftsartikel (refereegranskat)abstract
- Trivalent lanthanide-like metal ions coordinate nine water oxygen atoms, which form a tricapped trigonal prism in a large number of crystalline hydrates. Water deficiency, randomly distributed over the capping positions, was found for the smallest metal ions in the isomorphous nonahydrated trifluoromethanesulfonates, [M(H2O)(n)]CF3SO3)(3), in which M=Sc-III, Lu-III, Yb-III, Tm-III or Er-III. The hydration number n increases (n=8.0(1), 8.4(1), 8.7(1), 8.8(1) and 8.96(5), respectively) with increasing ionic size. Deuterium (H-2) solid-state NMR spectroscopy revealed fast positional exchange between the coordinated capping and prism water molecules; this exchange started at temperatures higher than about 280 K for lutetium(m) and below 268 K for scandium(m). Similar positional exchange for the fully nonahydrated yttrium(m) and lanthanum(m) compounds started at higher temperatures, over about 330 and 360 K, respectively. An exchange mechanism is proposed that can exchange equatorial and capping water molecules within the restrictions of the crystal lattice, even for fully hydrated lanthanoid(III) ions. Phase transitions occurred for all the water-deficient compounds at; 185 K. The hydrated scandium(III) trifluoromethanesulfonate transforms reversibly (Delta H degrees= -0.80(1) kJ mol(-1) on cooling) to a trigonal unit cell that is almost nine times larger, with the scandium ion surrounded by seven fully occupied and two partly occupied oxygen atom positions in a distorted capped trigonal prism. The hydrogen bonding to the trifluoromethanesulfonate anions stabilises the trigonal prism of water ligands, even for the crowded hydration sphere of the smallest metal ions in the series. Implications for the Lewis acid catalytic activity of the hydrated scandium(III) and lanthanoid(III) trifluoromethanesulfonates for organic syntheses performed in aqueous media are discussed.
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| 10. |
- Almkvist, Gunnar, et al.
(författare)
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Distribution of iron and sulfur and their speciation in relation to degradation processes in wood from the Swedish warship Vasa
- 2011
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 35, s. 1491-1502
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Tidskriftsartikel (refereegranskat)abstract
- Wood samples from the Swedish warship Vasa were analysed by scanning electron microscopy and X-ray absorption spectroscopy with the focus on speciation and distribution of iron and sulfur compounds in the wood matrix. Both these elements were found at high concentration (10–100 mg/g) in the surface region as a result of former accumulation of iron sulfides, elemental sulfur and reduced organic sulfur species (ROSS). Below the surface region, iron was the dominating element (1–10 mg/g) present both as iron(II) and iron(III) compounds, which diffused into the wood matrix from corroding iron bolts and other iron items during the time in the sea (1628–1961). Electron microscopy results revealed that iron and sulfur are present in a variety of particles of different sizes and compositions in the surface region, in contrast to the interior where few particles were found. Here, the presence of iron compounds of nano-particle size inside the cell walls enables a close contact between the wood polymers and reactive oxygen species originating from reactions with iron compounds. The presence of ROSS seems to have played an important role as scavengers of reactive oxygen species. Samples with high iron : ROSS ratio displayed evident signs of degradation as indicated by depolymerisation of wood components accompanied by increased acidity due to low molecular organic acids. The observations strengthen the hypothesis of the pro-oxidative and antioxidant properties of iron and ROSS compounds, respectively, and that the chemical activities of these elements play crucial roles in the long term preservation of wooden maritime artefacts
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| 11. |
- Almkvist, Gunnar, et al.
(författare)
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K-edge XANES analysis of sulfur compounds: an investigation of the relative intensities using internal calibration
- 2010
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Ingår i: Journal of Synchrotron Radiation. - 0909-0495 .- 1600-5775. ; 17, s. 683-688
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Tidskriftsartikel (refereegranskat)abstract
- Sulfur K-edge XANES (X-ray absorption near-edge structure) spectroscopy is an excellent tool for determining the speciation of sulfur compounds in complex matrices. This paper presents a method to quantitatively determine the kinds of sulfur species in natural samples using internally calibrated reference spectra of model compounds Owing to significant self-absorption of formed fluorescence radiation in the sample itself the fluorescence signal displays a non-linear correlation with the sulfur content over a wide concentration range. Self-absorption is also a problem at low total absorption of the sample when the sulfur compounds are present as particles. The post-edge Intensity patterns of the sulfur K-edge XANES spectra vary with the type of sulfur compound, with reducing sulfur compounds often having a higher post-edge intensity than the oxidized forms. In dilute solutions (less than 0.3-0.5%) it is possible to use sulfur K-edge XANES reference data for quantitative analysis of the contribution from different species The results show that it is essential to use an internal calibration system when performing quantitative XANES analysis Preparation of unknown samples must take both the total absorption and possible presence of self-absorbing particles into consideration.
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| 12. |
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| 13. |
- Bajnóczi, Eva, et al.
(författare)
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Speciation and structure of tin(II) in hyper-alkaline aqueous solution
- 2014
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Ingår i: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9226 .- 1477-9234. ; 43, s. 17971–17979-
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Tidskriftsartikel (refereegranskat)abstract
- The identity of the predominating tin(II)-hydroxide complex formed in hyper-alkaline aqueous solutions (0.2 <= C-NaOH <= 12 mol dm(-3)) is determined by potentiometric titrations, Raman, Mossbauer and XANES spectroscopy, supplemented by quantum chemical calculations. Thermodynamic studies using a H-2/Pt electrode up to free hydroxide concentrations of 1 mol dm(-3) showed the presence of a single monomeric complex with a tin(II) : hydroxide ratio of 1 : 3. This observation together with Raman and Mossbauer spectroscopic measurements supplemented by quantum mechanical calculations proved that the predominating complex is [Sn(OH)(3)](-), and that the presence of the other possible complex, [SnO(OH)](-), could not be proven with either experiments or simulations. The structure of the trihydroxidostannate(II) complex, [Sn(OH)(3)](-), was determined by EXAFS and was found to be independent of the applied hydroxide and tin(II) concentrations. The mean Sn-O bond distance is short, 2.078 angstrom, and in very good agreement with the only structure reported in the solid state. It is also shown that at pH values above 13 the speciation of the predominant trihydroxidostannate(II) complex is not affected by the presence of high concentrations of chloride ions.
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| 14. |
- Bajnóczi, Eva, et al.
(författare)
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Speciation and the structure of lead(II) in hyperalkaline aqueous solution
- 2014
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Ingår i: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9226 .- 1477-9234. ; 43, s. 17539-17543
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Tidskriftsartikel (refereegranskat)abstract
- The identity of the predominating lead(II) species in hyper-alkaline aqueous solution has been determined by Raman spectroscopy, and ab initio quantum chemical calculations and its structure has been determined by EXAFS. The observed and calculated Raman spectra for the [Pb(OH)(3)](-) complex are in agreement while they are different for two-coordinated complexes and complexes containing Pb=O double bonds. Predicted bond lengths are also consistent with the presence of [Pb(OH)(3)](-) and exclude the formation of Pb=O double bond(s). These observations together with experimentally established analogies between lead(II) and tin(II) in hyper-alkaline aqueous solutions suggest that the last stepwise hydroxido complex of lead(II) is [Pb(OH)(3)](-). The Pb-O bond distance in the [Pb(OH)(3)](-) complex as determined is remarkably short, 2.216 angstrom, and has low symmetry as no multiple back-scattering is observed. The [Pb(OH)(3)](-) complex has most likely trigonal pyramidal geometry as all reported three-coordinated lead(II) complexes in the solid state. From single crystal X-ray data, the bond lengths for O-coordinated lead(II) complexes with low coordination numbers are spread over an unusually wide interval, 2.216-2.464 angstrom for N = 3. The Pb-O bond distance is at the short side and within the range of three coordinated complexes, as also observed for the trihydroxidostannate(II) complex indicating that the hydroxide ion forms short bonds with d(10)s(2) metal ions with occupied anti-bonding orbitals.
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| 15. |
- Berggren Kleja, Dan, et al.
(författare)
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Bismuth(III) Forms Exceptionally Strong Complexes with Natural Organic Matter
- 2022
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 56, s. 3076-3084
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Tidskriftsartikel (refereegranskat)abstract
- The use of bismuth in the society has steadily increased during the last decades, both as a substitute for lead in hunting ammunition and various metallurgical applications, as well as in a range of consumer products. At the same time, the environmental behavior of bismuth is largely unknown. Here, the binding of bismuth(III) to organic soil material was investigated using extended X-ray absorption spectroscopy (EXAFS) and batch experiments. Moreover, the capacity of suwannee river fulvic acid (SRFA) to enhance the solubility of metallic bismuth was studied in a long-term (2 years) equilibration experiment. Bismuth(III) formed exceptionally strong complexes with the organic soil material, where >99% of the added bismuth(III) was bound by the solid phase, even at pH 1.2. EXAFS data suggest that bismuth(III) was bound to soil organic matter as a dimeric Bi3+ complex where one carboxylate bridges two Bi3+ ions, resulting in a unique structural stability. The strong binding to natural organic matter was verified for SRFA, dissolving 16.5 mmol Bi per gram carbon, which largely exceeds the carboxylic acid group density of this compound. Our study shows that bismuth(III) will most likely be associated with natural organic matter in soils, sediments, and waters.
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| 16. |
- Berggren Kleja, Dan, et al.
(författare)
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Characterization of iron in floating surface films of some natural waters using EXAFS
- 2012
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Ingår i: Chemical Geology. - : Elsevier. - 0009-2541 .- 1872-6836. ; 326, s. 19-26
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Tidskriftsartikel (refereegranskat)abstract
- Floating, iron bearing films have been observed in a wide range of environments, including wetlands, seep waters in ground water discharge areas, small rivers and lakes. To date, knowledge about their formation and composition is scarce. We have investigated the form of iron in floating iron-rich films of different origin, including a pond and a brook, as well as seep water pools of a groundwater discharge area. Sampling sites were located in southern (pond, brook) and central (seep pools) Sweden. Synchrotron-based X-ray absorption spectroscopy (EXAFS and XANES) allowed identification of the iron precipitates present in the films, without any pretreatment. The EXAFS data showed that the iron containing phase formed in the floating films varied in composition between the sites investigated. In the films from two ground water discharge areas, characterized by out-flowing iron(II) rich ground water being high in pH and low in DOC, the iron phase was completely dominated by ferrihydrite. In contrast, surface films sampled from the brook and the pond, the iron speciation showed a mixture of iron(III)-organic complexes and iron (hydr)oxide (most likely ferrihydrite). These waters were oxic and contained higher concentration of DOC than the seep water pools in the ground water discharge areas. The position of the pre-edge peak, which is sensitive to the oxidation state of iron, did not indicate occurrence of iron (II) in any of the films. Elemental composition of one film (seep water), suggested that films contained about one third of organic matter. Ferrihydrite is probably present as small particles with humic material sorbed onto surfaces or included in the particles, making the particles sufficiently hydrophobic to not settle without physical disturbance. The films are fragile and break easily down and become suspended upon disturbance. More studies are warranted in order to understand the mechanism of the formation of these fascinating films and their biogeochemical role.
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| 17. |
- Berggren Kleja, Dan, et al.
(författare)
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Silver(I) Binding Properties of Organic Soil Materials Are Different from Those of Isolated Humic Substances
- 2016
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 50:14, s. 7453-7460
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Tidskriftsartikel (refereegranskat)abstract
- The solubility of silver(I) in many soils is controlled by complexation reactions with organic matter. In this work we have compared the ability of isolated humic and fulvic acids to bind silver(I) with that of mor and peat materials. One new data set for Suwannee River Fulvic Acid was produced, which was consistent with published data sets for isolated fulvic and humic acids. The ability of soil materials to bind silver(I) was studied as a function of pH in the range 2.5-5.0, at a wide range of silver(I)-to-soil ratios (10(-4.2) - 10(-1.9) mol kg(-1)). By calibrating the Stockholm Humic Model on the humic and fulvic acids data sets, we showed that binding of silver(I) to both types of soil materials was much stronger (up to 2 orders of magnitude) than predicted from the silver(I) binding properties of the isolated humic materials. Thus, the approach taken for many other metals, that is, to model solubility in soils by using metal and proton binding parameters derived from isolated humic and fulvic acids, cannot be used for silver(I). One possible explanation for the discrepancy could be that silver(I) predominately interacted with various biomolecules in the soil samples, instead of humic- and fulvic-acid type materials.
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| 18. |
- Bergqvist, Claes, 1977-, et al.
(författare)
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Accumulation and speciation of arsenic in vegetables cultivated in soils with various As availability
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The toxicity of arsenic (As) in the environment is controlled by its concentration, availability and speciation. The aims of the study were to evaluate the accumulation and speciation of As in three vegetables (carrot, lettuce, spinach) cultivated in both contaminated and natural soils with various As concentrations and to estimate the concomitant health risks associated with the consumption of the vegetables. Arsenic concentration and speciation in plant tissues and soils was analysed by HPLC, AAS and X-ray absorption near-edge structure (XANES) spectroscopy. To estimate the plants influence in the rhizosphere, organic acids in lettuce root exudates were analysed by ion chromatography. The results showed that the As accumulation was higher in plants cultivated in soil with higher As extractability. Arsenate predominated in the soils, rhizosphere and root exudates of lettuce. Succinic acid was the major organic acid in lettuce root exudates. Arsenite was the predominating As species in the shoots of healthy looking plants. In plants showing signs of phytotoxicity, arsenate was predominating. Ingestion of the tested vegetables may result in an intake of elevated levels of As.
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| 19. |
- Bergqvist, Claes, et al.
(författare)
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Plants influence on arsenic availability and speciation in the rhizosphere, roots and shoots of three different vegetables
- 2014
-
Ingår i: Environmental Pollution. - : Elsevier BV. - 0269-7491 .- 1873-6424. ; 184, s. 540-546
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Tidskriftsartikel (refereegranskat)abstract
- The toxicity of arsenic (As) in the environment is controlled by its concentration, availability and speciation. The aims of the study were to evaluate the accumulation and speciation of As in carrot, lettuce and spinach cultivated in soils with various As concentrations and to estimate the concomitant health risks associated with the consumption of the vegetables. Arsenic concentration and speciation in plant tissues and soils was analysed by HPLC, AAS and XANES spectroscopy. To estimate the plants influence in the rhizosphere, organic acids in lettuce root exudates were analysed by ion chromatography. The results showed that the As accumulation was higher in plants cultivated in soil with higher As extractability. Arsenate predominated in the soils, rhizosphere and root exudates of lettuce. Succinic acid was the major organic acid in lettuce root exudates. Ingestion of the tested vegetables may result in an intake of elevated levels of inorganic As.
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| 20. |
- Björnsson, Gunnar, 1969-
(författare)
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Moral internalism : An Essay in Moral Psychology
- 1998
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- An ancient but central divide in moral philosophy concerns the nature of opinions about what is morally wrong or what our moral duties are. Some philosophers argue that moral motivation is internal to moral opinions: that moral opinions consist of motivational states such as desires or emotions. This has often been seen as a threat to the possibility of rational argument and justification in morals. Other philosophers argue that moral motivation is external to moral opinion: moral opinions should be seen as beliefs about moral reality, beliefs which may or may not motivate depending on whether the person holding them cares about moral matters.In this essay it is argued that although the traditional case for the internalist position fails, the total available evidence and methodological considerations support an internalist theory formulated in terms of a relatively rich psychological model. It is shown how such a theory can explain not only the practical character of moral opinions and their connection to moral emotions but also phenomena that have been taken to suggest an externalist picture, such as the role of inference, inconsistency, argument and explanations in moral discussion, as well as cases of amoralism and psychological disturbance. In the end, it is concluded that externalist explanations of the same phenomena are methodologically inferior for postulating a more complicated psychology.
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| 21. |
- Borg, Sixten, et al.
(författare)
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Budget impact analysis of surgical treatment for obesity in Sweden
- 2012
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Ingår i: Scandinavian Journal of Surgery. - : Sage Publications. - 1457-4969 .- 1799-7267. ; 101:3, s. 190-197
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Tidskriftsartikel (refereegranskat)abstract
- Background: The recent substantial increase in the number of obese surgeries performed in Sweden has raised concerns about the budget impact.Objective: Our aim in this paper is to present an assessment of the budgetary impact of different policies for surgical intervention for obese and overweight subjects from a healthcare perspective in Sweden.Methods: The model simulates the annual expected treatment costs of obesity related diseases and surgery in patients of different sex, age and Body Mass Index (BMI). Costs evaluated are costs of surgery plus the excess treatment costs that an obese patient has over and above the treatment costs of a normal-weight patient. The diagnoses that are included for costs assessment are diabetes and cardiovascular disease since these diagnoses are the principal diagnoses associated with obesity. Four different scenarios over the number of surgical operations performed each year are simulated and compared: (1) no surgical operation, (2) 3 000 surgical operations in persons with BMI > 40, (3) 4 000 (BMI > 40), and (4) 5 000 (expanded to BMI > 38).Results: Comparing Scenario 2 with Scenario 1 results in a net budget impact of on average SEK 121 million per annum or SEK 40 000 per patient. This implies that 55 percent of the cost of surgery, set equal to SEK 90 000 for each patient, has been offset by a reduction in the excess treatment costs of obesity related diseases. Expanding annual surgery from 3000 to 4000 the cost-offset increased to 58%. By expanding annual surgery further from 4000 to 5000 and at the same time expanding the indication for surgery from BMI > 40 to BMI > 38, no cost-offset is obtained.Conclusion: A cost-minimization strategy for bariatric surgery in Sweden should not expand indication, but rather increase the number of surgeries within the currently accepted indication.
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| 22. |
- Borg, Sixten, et al.
(författare)
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Obesity and Surgical Treatment - A Cost-Effectiveness Assessment for Sweden
- 2014
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Ingår i: Nordic Journal of Health Economics. - 1892-9729. ; , s. 257-275
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Tidskriftsartikel (refereegranskat)abstract
- The rising trend in the prevalence of obesity has become a major public health concern in many countries during the past decades, partly because being obese is associated with comorbidities and death. The cost of treatment for obesity related diseases has become a heavy burden on the national health care budget in many countries. The treatment options for obesity are mainly weight management therapies in the form of diet and exercise, pharmacological therapy, and surgery. The incidence of bariatric surgery in Sweden has increased eight-fold in the last decade. Our objective was to assess the cost-effectiveness of gastric bypass surgical treatments for obesity in adult patients, in comparison with conventional treatment, in Sweden from a societal perspective. The conventional treatment alternative consisted of the prevalent mixture of non-surgical obesity treatments. A model of individual patients was used to simulate the outcomes of the patients in terms of treatment costs, indirect costs, life years, and quality adjusted life years (QALY) over a lifetime perspective. In patients with a Body Mass Index of 40-44 kg/m2, surgery was estimated to be cost-saving in men and judged cost-effective in women, with an incremental cost per QALY gained of SEK 26 thousand (EUR 3 thousand). The incremental cost associated with gastric bypass decreases with BMI, increases with the patient's age, and is higher in women than in men. Taking patient characteristics and uncertainty in input data and model design into account, the incremental cost is estimated to be at most SEK 160 thousand per QALY gained (about EUR 18 thousand per QALY). In conclusion, gastric bypass surgery appears to be a cost-effective intervention compared to conventional treatment in adult persons with obesity in Sweden.
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| 23. |
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| 24. |
- Boye, Kristin, et al.
(författare)
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Quantification of chemical sulphur species in bulk soil and organic sulphur fractions by S K-edge XANES spectroscopy
- 2011
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Ingår i: European Journal of Soil Science. - : Wiley. - 1351-0754 .- 1365-2389. ; 62, s. 874–881-
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Tidskriftsartikel (refereegranskat)abstract
- A new data treatment method for fitting spectra obtained by sulphur (S) K-edge X-ray absorption near-edge structure (XANES) spectroscopy was used to quantify the chemical S speciation at three experimental sites with arable soils receiving the same long-term field treatments. Two treatments, crop residue (CR) incorporation and farmyard manure (FYM) application, with equal applications of mineral nutrients were included in the study. In the new data treatment method, internally calibrated spectra of dilute solutions (30 mm) of model compounds were used to fit the sample spectra. This greatly enhanced the reliability of quantitative determination of contributing S species in soil samples and soil extracts. The results indicated that long-term FYM application shifted S species composition from highly oxidized towards intermediate oxidization in two of the soils, but in the third soil the opposite trend was observed. Sulphur XANES spectroscopy of acetylacetone extracts of physically protected and unprotected organic S in two of the soils revealed that physical protection was not related to S speciation; however, intermediate forms of oxidized S species appeared to accumulate in the residual S pool (not extractable by acetylacetone)
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| 25. |
- Bruneau, Alexandre, et al.
(författare)
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Synthesis of Benzofurans and Indoles from Terminal Alkynes and Iodoaromatics Catalyzed by Recyclable Palladium Nanoparticles Immobilized on Siliceous Mesocellular Foam
- 2017
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Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 23:52, s. 12886-12891
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Tidskriftsartikel (refereegranskat)abstract
- Herein, we report on the utilization of a heterogeneous catalyst, consisting of Pd nanoparticles supported on a siliceous mesocellular foam (Pd-0-AmP-MCF), for the synthesis of heterocycles. Reaction of o-iodophenols and protected o-iodoanilines with acetylenes in the presence of a Pd nanocatalyst produced 2-substituted benzofurans and indoles, respectively. In general, the catalytic protocol afforded the desired products in good to excellent yields under mild reaction conditions without the addition of ligands. Moreover, the structure of the reported Pd nanocatalyst was further elucidated with extended X-ray absorption fine-structure spectroscopy, and it was proven that the catalyst could be recycled multiple times without significant loss of activity.
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