| 1. |
- Kharitonov, D. S., et al.
(author)
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Corrosion of AD31 (AA6063) Alloy in Chloride-Containing Solutions
- 2018
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In: Protection of Metals and Physical Chemistry of Surfaces. - : MAIK NAUKA/INTERPERIODICA/SPRINGER. - 2070-2051. ; 54:2, s. 291-300
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Journal article (peer-reviewed)abstract
- Corrosion of AD31 (AA6063) alloy in neutral 0.05 M NaCl solutions is investigated via scanningprobe microscopy, linear-sweep voltammetry, and electrochemical-impedance spectroscopy. Al−Fe−Si−Mg intermetallic particles are determined to prevail in the structure of alloy and act as local cathodes. Intermodulation electrostatic-force-microscopy imaging shows that their Volta potential differs by 570 mV from that of the host aluminum matrix, making the alloy prone to localized corrosion. We show that the corrosion of alloy in the studied electrolyte mainly develops locally and results in pitting, with charge transfer being the limiting stage of the process. A mechanism of corrosion of the AD31 (AA6063) alloy in neutral chloride-containing solutions is proposed.
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| 2. |
- Malmsten, M, et al.
(author)
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Mucin layers on hydrophobic surfaces studied with ellipsometry and surface force measurements
- 1992
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In: Journal of Colloid and Interface Science. - 0021-9797 .- 1095-7103. ; 151, s. 579-590
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Journal article (peer-reviewed)abstract
- The forces acting between layers of gastric mucins from rat (RGM) and pig (PGM) adsorbed on to hydrophobized mica surfaces were investigated by using the surface force technique, whereas information on the kinetics and the reversibility of the adsorption process was obtained with ellipsometry. From the surface force measurements, we found that the amount adsorbed from a 0.1 mg/ml RGM solution was 3.5±1.5 mg/m2 at adsorption equilibrium, within experimental error equal to that (about 3 mg/m2) found with ellipsometry. The forces obtained with RGM were purely repulsive, whereas those displayed by PGM were partially attractive. Dilution of the bulk solution caused only minor desorption and the interaction force between the RGM layers was only weakly dependent on the excess electrolyte concentration. Hence, steric forces predominate the interaction in the RGM system. Both RGM and PGM adsorb in a flat conformation, with compressed adsorbed layer thicknesses of 10-20 nm and 3-4 nm, respectively. The interaction force was essentially reversible on approach and separation for RGM, whereas 'relaxation effects' were prominent for PGM layers.
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| 3. |
- Uhnoo, I., et al.
(author)
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Treatment and prevention of influenza : Swedish recommendations
- 2003
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In: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 35:1
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Journal article (peer-reviewed)abstract
- The introduction of the 2 neuraminidase inhibitors (NAIs) zanamivir and oseltamivir has offered new options for the prevention and treatment of influenza. This article summarizes a Swedish consensus guidance document on the rational use of antiviral drugs in the management of influenza virus infections. Vaccination remains the cornerstone for influenza prophylaxis. Target groups for the annual vaccination programme are the 'at-risk' individuals, i.e. elderly patients (= 65 y) and patients with chronic pulmonary disease or cardiovascular disease or other chronic diseases predisposing for a complicated course of influenza. Antiviral drugs are not a substitute for influenza vaccination, but could be used as adjuncts. Currently, 3 drugs have been approved for the treatment of influenza, including zanamivir and oseltamivir and the M2 inhibitor amantadin. Amantadin has come to very limited use, has recently been withdrawn from the Swedish market and is available only on a named patient basis. Compared with amantadin, the NAIs have clear advantages because of their broader anti-influenza activity against both type A and B, improved safety profiles and low potential for inducing drug resistance. The NAIs are therefore recommended as first options in the treatment of influenza. Oseltamivir can be taken orally, whereas zanamivir is for oral inhalation. Limited in vitro and in vivo data suggest that oseltamivir is less potent against influenza B, whereas zanamivir seems equally effective against influenza A and B. In influenza-positive healthy adults and children, treated within 48 h after symptom onset, the NAIs shorten the duration of illness by about 1 d. No significant effect on the duration of symptoms has been documented in treated at-risk patients with influenza. Owing to their limited therapeutic benefit, general use of the NAIs in the treatment of influenza is not recommended, but they can be advocated on an individualized basis for patients with severe influenza who can start therapy within 48 h of the onset of symptoms. Zanamivir is the preferred choice in a confirmed influenza B epidemic. For prevention of influenza, 2 drugs are approved, oseltamivir in adults above 12 y old and amantadin in people above 10 y old. The 70-90% protective efficacy of oseltamivir for household postexposure prophylaxis and for seasonal prophylaxis is comparable to that reported for amantadin. Oseltamivir is the preferred drug for prophylactic use. Chemoprophylaxis is targeted at high-risk groups and should be considered on a case-by-case basis depending on the circumstances and the population requiring protection. A broader preventive use of oseltamivir can be advocated in at-risk groups during seasons when there is a poor antigenic match between the epidemic strains and the vaccine strains. Oseltamivir prophylaxis is otherwise recommended for patients unable to be vaccinated and for families exposed to influenza which include a member of the at-risk groups. In high-risk hospital units and in institutions caring for the elderly, oseltamivir prophylaxis, in combination with vaccination, can be recommended as measures to control an influenza outbreak.
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| 4. |
- Bastardo, LA, et al.
(author)
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Deuterium isotope effects on the interaction between hyperbranched polyethylene imine and an anionic surfactant
- 2005
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In: Journal of Physical Chemistry B. - 1520-6106 .- 1520-5207. ; 109, s. 16196-16202
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Journal article (peer-reviewed)abstract
- Solvent isotope effects on the interaction between the hyperbranched cationic polyelectrolyte, polyethylene imine (PEI), and the anionic surfactant sodium dodecyl sulfate (SDS) were investigated using potentiometric titration and eletrophoretic mobility measurements. In the basic pH range a significantly higher fraction of the amine groups was found to be protonated when the PEI was dissolved in D2O compared to H2O at the same pH/pD. The difference in polymer charge in the two solvents gradually decreases with decreasing pH and it completely diminishes at around pH=4. Electrophoretic mobility measurements of PEI/SDS complexes at different pH values correlated very well with these observations. At pH/pD≈9 a much higher mobility of the PEI/SDS complexes was found at low surfactant concentrations in D2O than in H2O, and the charge neutralization point shifted to a considerably larger surfactant concentration in heavy water. These results can be explained by the significantly higher charge density of the PEI in D2O compared to H2O. On the other hand, at the natural pH/pD as well as at pH=4 and pD=4 conditions the PEI molecules have roughly equal charge density which results in very similar charged characteristics (mobilities) of the PEI/SDS complexes as well as the same charge neutralization SDS concentration. It can be concluded, that extreme care must be taken in the general analysis of those experiments where weak polyelectrolyte/surfactant aggregates are investigated in heavy water and then these observations are correlated with structures of the same system in water.
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| 5. |
- Bastardo Zambrano, Luis Alejandro, et al.
(author)
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Deuterium isotope effects on the interaction between hyperbranched polyethylene imine and an anionic surfactant
- 2005
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In: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 109:33, s. 16196-16202
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Journal article (peer-reviewed)abstract
- Solvent isotope effects on the interaction between the hyperbranched cationic polyelectrolyte, polyethylene imine (PEI), and the anionic surfactant sodium dodecyl sulfate (SDS) were investigated using potentiometric titration and eletrophoretic mobility measurements. In the basic pH range, a significantly higher fraction of the amine groups was found to be protonated when the PEI was dissolved in D2O compared to H2O at the same pH/pD. The difference in polymer charge in the two solvents decreases gradually with decreasing pH, and it completely diminishes at around pH = 4. Electrophoretic mobility measurements of PEI/SDS complexes at different pH values correlated very well with these observations. At pH/pD approximate to 9 a much higher mobility of the PEI/SDS complexes was found in D2O than in H2O at low surfactant concentrations, and the charge neutralization point shifted to a considerably larger surfactant concentration in heavy water. These results can be explained by the significantly higher charge density of the PEI in D2O compared to H2O. However, at the natural pH/pD as well as at pH = 4 and pD = 4 conditions the PEI molecules have roughly equal charge densities, which result in very similar charged characteristics (mobilities) of the PEI/SDS complexes as well as the same charge neutralization SDS concentration. It can be concluded that extreme care must be taken in the general analysis of those experiments in which weak polyelectrolyte/surfactant aggregates are investigated in heavy water, and then these observations are correlated with structures of the same system in water.
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| 6. |
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| 7. |
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| 8. |
- Bergström, Lars Magnus, et al.
(author)
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Small-angle neutron scattering study of mixtures of cationic polyelectrolyte and anionic surfactant : Effect of polyelectrolyte charge density
- 2004
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In: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 108:6, s. 1874-1881
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Journal article (peer-reviewed)abstract
- We have studied mixtures of an anionic surfactant (deuterated sodium dodecyl sulfate, SDS-d) and cationic polyelectrolytes with different charge densities (10%, 30%, 60%, and 100%) using small-angle neutron scattering (SANS). Near compositions corresponding to charge neutralization, the solutions phase separate into a complex phase (precipitate) consisting of, in the cases of 30%, 60%, and 100% charge density, a two-dimensional (213) hexagonal lattice of close-packed cylindrical micelles and a clear liquid. When either polyelectrolyte with charge density less than 100% or SDS-d is present in sufficient excess, the solution becomes clear and isotropic, and from the scattering data we may conclude that prolate or rod-shaped micelles are present. The micelles are seen to grow in length with increasing SDS-d concentration and polyelectrolyte charge density from about 80 Angstrom to 550 Angstrom, whereas the cross-sectional radius is 15 Angstrom and approximately constant. The number of micelles per polyelectrolyte chain is found to be slightly larger than unity (1-6). In some of the (turbid) samples rod-shaped micelles are found to coexist with larger polyelectrolyte-surfactant complexes. Solutions consisting of 10% charged polyelectrolyte and SDS-d are very viscous and gellike, and the complex phase is much less defined with a much larger distance between adjacent aggregates in the complex phase.
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| 9. |
- Bergström, M, et al.
(author)
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Small-angle neutron scattering study of mixtures of cationic polyelectrolyte and anionic surfactant: Effect of polyelectrolyte charge density Polyelectrolyte and Anionic Surfactant: Effect of Polyelectrolyte Charge
- 2004
-
In: Journal of Physical Chemistry B. - 1520-6106 .- 1520-5207. ; 108, s. 1874-1881
-
Journal article (peer-reviewed)abstract
- We have studied mixtures of an anionic surfactant (deuterated sodium dodecyl sulfate, SDS-d) and cationic polyelectrolytes with different charge densities (10%, 30%, 60%, and 100%) using small-angle neutron scattering (SANS). Near compositions corresponding to charge neutralization, the solutions phase separate into a complex phase (precipitate) consisting of, in the cases of 30%, 60%, and 100% charge density, a two-dimensional (2D) hexagonal lattice of close-packed cylindrical micelles and a clear liquid. When either polyelectrolyte with charge density less than 100% or SDS-d is present in sufficient excess, the solution becomes clear and isotropic, and from the scattering data we may conclude that prolate or rod-shaped micelles are present. The micelles are seen to grow in length with increasing SDS-d concentration and polyelectrolyte charge density from about 80 Å to 550 Å, whereas the cross-sectional radius is 15 Å and approximately constant. The number of micelles per polyelectrolyte chain is found to be slightly larger than unity (1-6). In some of the (turbid) samples rod-shaped micelles are found to coexist with larger polyelectrolyte-surfactant complexes. Solutions consisting of 10% charged polyelectrolyte and SDS-d are very viscous and gellike, and the complex phase is much less defined with a much larger distance between adjacent aggregates in the complex phase.
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| 10. |
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