| 1. |
- Billsten, P, et al.
(författare)
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Adsorption of human carbonic anhydrase II onto silicon oxides surfaces : The effects of truncation in the N-terminal region
- 1998
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Ingår i: The Colloid Science of Lipids New Paradigms for Self-Assembly in Science and Technology. - 1435-1536 .- 0340-255X. - 9783798511125 - 9783798516557 ; 108, s. 161-165
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Konferensbidrag (refereegranskat)abstract
- The adsorption of human carbonic anhydrase II pseudo-wild type (HCAIIpwt) and an N-terminally truncated version thereof onto silica surfaces were studied. The amount adsorbed and the adsorption kinetics were measured using in situ ellipsometry. A substantial difference was seen between the two proteins. The adsorbed amount of the truncated version (2.53 mg/m2) indicates an end-on orientation, while the HCAIIpwt seems to adsorb side-on (1.84 mg/m2). It is suggested that the orientation effects arise from the truncation. The truncation is known to unfold the two most N-terminal helical segments, which could inhibit adsorption with the N-terminal region facing the surface, due to steric repulsion.
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| 2. |
- Boström, Mattias, et al.
(författare)
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Anion-Specific Partitioning in Two-Phase Finite Volume Systems : Possible Implications for Mechanisms of Ion Pumps.
- 2009
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 113:23, s. 8124-8127
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Tidskriftsartikel (refereegranskat)abstract
- In two-phase finite volume systems of electroneutral phospholipids, the electrolyte concentration is different in the two phases. The partitioning is highly anion-specific, a phenomenon not accounted for by classical electrolyte theories. It is explained if ionic dispersion forces that lead to specific ion binding are taken into account. The mechanism provides a contribution to active ion pumps not previously considered.
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| 3. |
- Boström, Mathias, et al.
(författare)
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Atomic resonance interaction in dielectric media
- 2004
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 69:5 B, s. 054701-1
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Tidskriftsartikel (refereegranskat)abstract
- The retarded resonance interaction in dielectric media between a ground state atom and an excited atom were investigated. The whole system was represented by a superposition of states:symmetric and antisymmetric with respect to interchange of atoms. While the antisymmetric state can be long lived, the asymmetric state is likely to decay into two ground state atoms. The retarded limit large deviations were demonstrated.
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| 4. |
- Boström, Mathias, et al.
(författare)
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Contributions from dispersion and born self-free energies to the solvation energies of salt solutions
- 2004
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 108:33, s. 12593-12595
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Tidskriftsartikel (refereegranskat)abstract
- That the Born theory provides an accurate means of calculating solvation energies of ions in water has been demonstrated by Rashin and Honig (Rashin, A. A., Honig, B. J. Phys. Chem. 1985, 89, 5588). They could fit the experimental solvation energies of a number of salts nicely by a simple increase of 7% in the expected radii of all ions. However, as we demonstrate herein, there is an important previously ignored contribution due to the ionic dispersion self-free energy. The ionic parameters necessary to estimate the different contributions to solvation energy are the ionic radii, the ionic polarizabilities, and the ionization potentials. Whereas the polarizabilities and ionization potentials of a number of salts have recently been derived ab initio (in both vacuum and water), the appropriate choices of radii are less well-known. We pursue two different approaches to assign the ionic radii. In the first approach, we find that an increase of all expected radii by 23% gives reasonable agreement between theory and experiment (to within 6%). In the second approach, we increased the expected radii of six ions separately (10-30%) to obtain a best fit for the nine salts investigated. In this second approach, the deviations between theory and experiment were less than 0.1%. The essential point is that a proper theory must include contributions from both electrostatic (Born) and electrodynamic (dispersion) self-free energies.
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| 5. |
- Boström, Mathias, et al.
(författare)
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Dispersion self-free energies and interaction free energies of finite-sized ions in salt solutions
- 2004
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Ingår i: Langmuir. - 0743-7463 .- 1520-5827. ; 20:18, s. 7569-7574
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Tidskriftsartikel (refereegranskat)abstract
- The role for many-body dipolar (dispersion) potentials in ion-solvent and ion-solvent-interface interactions is explored. Such many-body potentials, accessible in principle from measured dielectric data, are necessary in accounting for Hofmeister specific ion effects. Dispersion self-energy is the quantum electrodynamic analogue of the Born electrostatic self-energy of an ion. We here describe calculations of dispersion self-free energies of four different anions (OH-, Cl-, Br-, and I-) that take finite ion size into account. Three different examples of self-free energy calculations are presented. These are the self-free energy of transfer of an ion to bulk solution, which influences solubility, the dispersion potential acting between one ion and an air-water interface (important for surface tension calculations), and the dispersion potential acting between two ions (relevant to activity coefficient calculations). To illustrate the importance of dispersion self-free energies, we compare the Born and dispersion contributions to the free energy of ion transfer from water to air (oil). We have also calculated the change in interfacial tension with added salt for air (oil)-water interfaces. A new model is used that includes dispersion potentials acting on the ions near the interface, image potentials, and ions of finite size that are allowed to spill over the solution-air interface. It is shown that interfacial free energies require a knowledge of solvent profiles at the interface.
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| 6. |
- Boström, Mathias, 1970-, et al.
(författare)
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Dissolved gases
- 2005
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Ingår i: Water encyklopedia. - Hoboken, New Jersey : Wiley. - 9780471736875 - 0471736872 ; , s. 450-452
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Leading experts in water-related fields have come together to make Water Encyclopedia a one-stop, comprehensive reference about the world s most important natural resource. It covers designated topics in a clear concise and authoritative manner. The treatment is practical in orientation, keeping in mind the needs of the users. Theory is included only where required for an understanding of the topic.
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| 7. |
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| 8. |
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| 9. |
- Boström, Mathias, 1970-, et al.
(författare)
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Hofmeister effects
- 2005
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Ingår i: Water encyclopedia. - Hoboken, New Jersey : Wiley. - 0471736872 - 9780471736875 ; , s. 468-471
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Leading experts in water-related fields have come together to make Water Encyclopedia a one-stop, comprehensive reference about the world s most important natural resource. It covers designated topics in a clear concise and authoritative manner. The treatment is practical in orientation, keeping in mind the needs of the users. Theory is included only where required for an understanding of the topic.
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| 10. |
- Boström, Mathias, et al.
(författare)
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Hofmeister effects in surface tension of aqueous electrolyte solution
- 2005
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 21:6, s. 2619-2623
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Tidskriftsartikel (refereegranskat)abstract
- The surface tension of electrolyte solutions shows marked specific ion effects. We here show an important role for both ionic solvation energies and ionic dispersion potentials in determining this ion specific surface tension of salt solutions. The ion self-free energy changes when an ion moves from bulk solution into the interfacial region, with its decreasing water density profile. We will show that the solvation energies of different ions correlate very well with the surface tension of salt solutions. Inclusion of this distance-dependent self-free energy contribution brings qualitative agreement with experiments and the right Hofmeister series. This is so not only for surface tension changes but also for measured surface potentials. The inclusion of ionic dispersion interaction potentials further improves the agreement with experiments. We discuss how further progress in the theory of the surface tension of salts can be achieved. © 2005 American Chemical Society.
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