| 1. |
- Mattisson, C, et al.
(author)
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Diffusivity measurements using holographic laser interferometry in a cubic lipid-water phase
- 1996
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In: Chemistry and Physics of Lipids. - 0009-3084. ; 84:1, s. 1-12
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Journal article (peer-reviewed)abstract
- The diffusion of glucose in a cubic lipid-water phase was studied with holographic laser interferometry. The X-ray diffraction data showed that the structure of the cubic phase could be described as a primitive cubic lattice under the experimental conditions used. The present study shows that holographic laser interferometry is suitable for determining the concentration profile due to diffusion, even for such intriguing structures as cubic lipid-water phases. The concentration profile obtained revealed that the diffusion process can be described by Fick's Second Law, and the effective diffusion coefficient was obtained by fitting a theoretical concentration profile to the experimental data. The diffusion coefficient obtained for glucose was four times smaller than the corresponding coefficient in aqueous bulk solution. The effective diffusion coefficient in the cubic phase is greater than that predicted by models developed for polymer gels.
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| 2. |
- Svensson, I., et al.
(author)
-
Phase behaviour of aqueous systems of enzymatically modified phosphatidylcholines with one hexadecyl and one hexyl or octyl chain
- 1993
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In: Chemistry and Physics of Lipids. - 0009-3084. ; 66:3, s. 195-197
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Journal article (peer-reviewed)abstract
- Phosphatidylcholines composed of a hexadecyl chain in the 2-position and a hexyl or octyl chain in the l-position (C6C16PC or C8C16PC) were prepared from dipalmitoylphosphatidylcholine by lipase-catalyzed transesterification; the aqueous phase properties of the products were examined. In the C8C16PC-water system, a lamellar liquid-crystalline phase was dominant. Like all long-chain phosphatidylcholines studied earlier, a liposomal dispersion was formed in the presence of excess water. In the C6C16PC system, a new type of phase behaviour was observed; at high water content, an L3 phase was formed.
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| 3. |
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| 4. |
- Nilsson, A., et al.
(author)
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An FTIR study of the hydration and molecular ordering at phase transitions in the monooleoylglycerol/water system
- 1994
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In: Chemistry and Physics of Lipids. - : Elsevier BV. - 0009-3084 .- 1873-2941. ; 71:2, s. 119-131
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Journal article (peer-reviewed)abstract
- The liquid-crystalline phases of monooleoylglycerol and water have been investigated by FTIR spectroscopy. The use of polarized IR radiation made it possible to obtain the order parameters of transition moments in the lipid molecule. The order parameters as a function of the temperature and water content have been studied for the lamellar liquid-crystalline phase (L(α)). The decrease in the ordering of the C=O and C-O-CO stretching vibrations in the polar headgroup started earlier than for the CH=CH and CH2 stretching vibrations in the acyl chain region at the phase transition between lamellar and non-lamellar structures. The hydration of the ester carbonyl group increased with the water content. The ordering of the acyl chain decreases drastically in the two-phase regions, while it is nearly constant in the L(α) phase.
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| 5. |
- Silvander, Mats, et al.
(author)
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Effects of PEG-lipids on permeability of phosphatidylcholine/cholesterol liposomes in buffer and in human serum
- 1998
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In: Chemistry and Physics of Lipids. - 0009-3084 .- 1873-2941. ; 97:1, s. 15-26
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Journal article (peer-reviewed)abstract
- The permeability of liposomal membranes was studied as a function of the amount of incorporated PEG-lipid. The fluorescent dyes ethidium, propidium and 5(6)-carboxy fluorescein were used as markers for measurements of spontaneous leakage. The results show that addition of up to 8 mol% of PEG(2000)-DSPE into liposomal membranes of DSPC/Cho and EPC/Cho reduces the permeability of carboxyfluorescein in buffer solution. In contrast, the leakage of the more amphiphilic dye ethidium was not to any measurable extent affected by PEG-lipid inclusion. Another important difference was that ethidum leakage showed a clear dependence on temperature whereas leakage of carboxyfluorescein from pegylated liposomes did not. We conclude that the mechanisms by which the two dyes permeate the liposomal bilayer are qualitatively different. Both ethidium and carboxyfluorescein did interact with human serum components in a way that made measurements in serum unreliable. The more hydrophilic ethidium analogue propidium was shown not to interact with human serum components to any detectable extent. This made propidium suitable for permeability determinations in human serum. It was found that liposomes composed of pure EPC or EPC with 5 mol% DSPE-PEG, displayed a dramatic increase in permeability when subjected to a medium composed of 20% human serum in buffer. Addition of 40 mol% cholesterol to the EPC bilayers reduced the observed release rate in human serum substantially, whereas no stabilizing effect was observed upon PEG-lipid inclusion.
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| 6. |
- Dahim, M, et al.
(author)
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Solubilization of phospholipid/triacylglycerol aggregates by non-ionic surfactants
- 1998
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In: CHEMISTRY AND PHYSICS OF LIPIDS. - : ELSEVIER SCI IRELAND LTD. - 0009-3084. ; 97:1, s. 1-14
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Journal article (other academic/artistic)abstract
- The aggregates formed by sonication of mixtures of triacylglycerols (triglycerides) (TG) and egg phosphatidylcholine (EPC) have been examined at 25 degrees C at 6 [TG]/[EPC] ratios ranging from 0 to approximate to 1 (mol/mol) by gel exclusion chromatograp
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| 7. |
- Nyilas, A
(author)
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A new protecting group: 9-fluorenylmethoxycarbonyl (FMOC) in the synthesis of 1,2-diacylglycerols
- 1997
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In: CHEMISTRY AND PHYSICS OF LIPIDS. - : ELSEVIER SCI IRELAND LTD. - 0009-3084. ; 87:2, s. 171-174
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Journal article (other academic/artistic)abstract
- The synthesis of 1,2-L-dipalmitoyl-sn-glycerol, 1,2-L-distearoyl-sn-glycerol and 1,2-L-dioleoyl-sn-glycerol are described here using 9-fluorenylmethoxycarbonyl (FMOC) group for protection of the S-position of glycerol which can be selectively removed by E
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| 8. |
- Nyilas, A
(author)
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Synthesis of 1-beta-D-arabinofuranosyl-cytosine 5'-phosphate-L-1,2-diacylglycerols
- 1997
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In: CHEMISTRY AND PHYSICS OF LIPIDS. - : ELSEVIER SCI IRELAND LTD. - 0009-3084. ; 89:1, s. 75-81
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Journal article (other academic/artistic)abstract
- 5'-O-MMTr-cytosine arabinoside was prepared on a large scale from 5'-O-MMTr-cytidine with diphenyl carbonate via 5'-protected cytidine-2',3'-carbonate-ara-cytidine-2',2-anhydro derivative at a 67% yield. 1,2-Dipalmitoyl-sn-glycerol, 1,2-distearoyl-sn-glyc
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