| 1. |
- Hammarlund, Dan, et al.
(författare)
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Climate and environment during the Younger Dryas (GS-1) as reflected by composite stable isotope records of lacustrine carbonates at Torreberga, southern Sweden
- 1999
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Ingår i: Journal of Quaternary Science. - 1099-1417. ; 14:1, s. 17-28
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Tidskriftsartikel (refereegranskat)abstract
- Climatic and environmental changes during the Younger Dryas stadial (GS-1) and preceding and following transitions are inferred from stable carbon and oxygen isotope records obtained from the sediments of ancient Lake Torreberga, southern Sweden. Event GS-1 is represented in the sediment sequence by 3.5 m of clay containing lacustrine carbonates of various origins. Comparison of isotopic records obtained on mollusc shells, ostracod valves, and Chara encrustations precipitated during specific seasons of the year supports estimates of relative changes in both lake water and mean annual air temperatures. Variations in soil erosion rates can also be estimated from a simple isotope-mass-balance model to separate allochthonous and autochthonous carbonate contributions to the bulk carbonate content of the sediments. The well-known, rapid climatic shifts characterising the Last Termination in the North Atlantic region are clearly reflected in the isotopic data, as well as longer-term changes within GS-1. Following maximum cooling shortly after the Allerod-Younger Dryas (GI-1-GS-1) transition, a progressive warming and a slight increase in aquatic productivity is indicated. At the Younger Dryas-Preboreal (GS-1-PB) transition mean annual air temperature rapidly increased by more than 5 degrees C and summer lake-water temperature increased by ca. 12 degrees C. The subsequent Preboreal oscillation is characterised by an increase in soil erosion and a slight decrease in mean annual air temperature. These results are in harmony with recent findings about large-scale climate dynamics during the Last Termination. Copyright (C) 1999 John Wiley & Sons, Ltd.
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| 2. |
- Rogers, David, et al.
(författare)
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Highlights of Coastal Waves 1996
- 1998
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Ingår i: Bulletin of The American Meteorological Society - (BAMS). - 0003-0007 .- 1520-0477. ; 79, s. 1307-1326
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Rogers, DP, et al.
(författare)
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Highlights of Coastal Waves 1996
- 1998
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Ingår i: BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY. - : AMER METEOROLOGICAL SOC. - 0003-0007. ; 79:7, s. 1307-1326
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Tidskriftsartikel (refereegranskat)abstract
- Some of the highlights of an experiment designed to study coastal atmospheric phenomena along the California coast (Coastal Waves 1996 experiment) are described. This study was designed to address several problems, including the cross-shore variability a
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| 7. |
- Wasan, E K, et al.
(författare)
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A multi-step lipid mixing assay to model structural changes in cationic lipoplexes used for in vitro transfection
- 1999
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Ingår i: Biochimica et Biophysica Acta - Biomembranes. - 0005-2736 .- 1879-2642. ; 1461:1, s. 27-46
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Tidskriftsartikel (refereegranskat)abstract
- Formation of liposome/polynucleotide complexes (lipoplexes) involves electrostatic interactions, which induce changes in liposome structure. The ability of these complexes to transfer DNA into cells is dependent on the physicochemical attributes of the complexes, therefore characterization of binding-induced changes in liposomes is critical for the development of lipid-based DNA delivery systems. To clarify the apparent lack of correlation between membrane fusion and in vitro transfection previously observed, we performed a multi-step lipid mixing assay to model the sequential steps involved in transfection. The roles of anion charge density, charge ratio and presence of salt on lipid mixing and liposome aggregation were investigated. The resonance-energy transfer method was used to monitor lipid mixing as cationic liposomes (DODAC/DOPE and DODAC/DOPC; 1:1 mole ratio) were combined with plasmid, oligonucleotides or Na(2)HPO(4). Cryo-transmission electron microscopy was performed to assess morphology. As plasmid or oligonucleotide concentration increased, lipid mixing and aggregation increased, but with Na(2)HPO(4) only aggregation occurred. NaCl (150 mM) reduced the extent of lipid mixing. Transfection studies suggest that the presence of salt during complexation had minimal effects on in vitro transfection. These data give new information about the effects of polynucleotide binding to cationic liposomes, illustrating the complicated nature of anion induced changes in liposome morphology and membrane behavior.
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| 8. |
- WITTUNG, P, et al.
(författare)
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PHOSPHOLIPID MEMBRANE-PERMEABILITY OF PEPTIDE NUCLEIC-ACID
- 1995
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Ingår i: FEBS LETTERS. - 0014-5793. ; 365:1, s. 27-29
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Tidskriftsartikel (refereegranskat)abstract
- Phospholipid vesicles (liposomes) as membrane models have been used to study the penetration properties of peptide nucleic acid (PNA), a new DNA analog in which the nucleobases are attached to a pseudo-peptide backbone, The liposomes were characterised by
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| 9. |
- Wittung, Pernilla, 1968, et al.
(författare)
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Phospholipid membrane permeability of peptide nucleic acid
- 1995
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Ingår i: FEBS Letters. - : Wiley. - 1873-3468 .- 0014-5793. ; 365:1, s. 27-29
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Tidskriftsartikel (refereegranskat)abstract
- Phospholipid vesicles (liposomes) as membrane models have been used to study the penetration properties of peptide nucleic acid (PNA), a new DNA analog in which the nucleobases are attached to a pseudo-peptide backbone, The liposomes were characterised by carboxyfluorescein efflux, light-scattering and cryogenic transmission electron microscopy. The liposome structure was found not to be affected by the incorporation of PNA or an oligonucleotide. Two 10-mer fluorescein-labelled PNAs were found to have low efflux rates (half-times of 5.5 and 11 days), comparable to a 10-mer oligonucleotide (half-time of 7 days). We conclude that passive diffusion of unmodified PNA is not an effective way of transport into biological cells.
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