| 11. |
- Glans, Peter, et al.
(author)
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Dielectronic recombination of N4
- 2001
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In: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947. ; 649:4, s. 043609/1-043609/11
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Journal article (peer-reviewed)abstract
- The dielectronic recombination spectrum of N4+ has been measured with high resolution and accuracy. The 1s22p5l resonances in the energy range from 0 to 1.6 eV were studied in detail. The experimental spectrum is compared with the results from four different calculations. An almost perfect agreement between the experiment and a calculation which combines relativistic many-body perturbation theory and complex rotation is found. The calculation provides accurate spectroscopic data for all fifty 1s22p5l states. The literature value for the 1s22p5s 1P energy level is found to be off by more than 0.1 eV.
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| 12. |
- Glans, Peter, et al.
(author)
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Dielectronic recombination used as a tool for spectroscopic studies of highly charged ions
- 2004
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In: Physica scripta. T. - 0281-1847. ; T110, s. 212-215
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Journal article (peer-reviewed)abstract
- Systematic studies of electron-ion recombination for Li-like, Na-like, and Cu-like ions have been made during the last few years at the CRYRING facility. The main purpose has been to measure recombination spectra with such high resolution and accuracy that stringent tests of advanced atomic calculations of doubly excited states can be made. From the comparison with theory it is possible to obtain energy positions, as well as radiative and nonradiative decay rates for the doubly excited states. In addition, for heavy, highly charged ions it is possible to deduce radiative corrections for energy splittings with very high accuracy.
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| 13. |
- Griffiths, P. C., et al.
(author)
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Small-angle neutron scattering, electron paramagnetic resonance, electrophoretic NMR, and time-resolved fluorescence quenching studies of sodium dodecyl sulfate and tetra(ethylene oxide) dodecyl ether mixed surfactant micelles
- 2004
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In: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 108:4, s. 1351-1356
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Journal article (peer-reviewed)abstract
- Small-angle neutron scattering (SANS), time-resolved fluorescence quenching (TRFQ), electrophoretic NMR (ENMR), and electron paramagnetic resonance (EPR) have been used to study mixed micelles formed from the two dodecyl tailed surfactants, sodium dodecyl sulfate (SDS) and tetra(ethylene oxide) dodecyl ether. By combining the TRFQ and EPR techniques, one is essentially able to calculate the SANS data, lending significant weight to the micelle characteristics thus obtained. EPR reports the degree of hydration of the surfactant headgroups; TRFQ, the micelle aggregation number and inter alia the volume of the hydrophobic core. Given the physical dimensions of the surfactant, i.e., alkyl chain length, headgroup volumes, etc., it is then possible to calculate the micelle ellipticity and shell thickness. The ENMR studies provide a rather different but complementary estimate of the ionic character of the micelle. With increasing nonionic content, the aggregation number increases, the micelle becomes more elliptical, and the headgroup region of the micelle becomes less hydrated and significantly more viscous. The degree of sodium counterion dissociation shows an initial small decrease with decreasing SDS micelle mole fraction but subsequently increases, reflecting the interplay between the electrostatic character of the micelle surface and the micelle curvature.
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| 14. |
- Hertzberg, M., et al.
(author)
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A transcriptional roadmap to wood formation
- 2001
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In: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 98:25, s. 14732-14737
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Journal article (peer-reviewed)abstract
- The large vascular meristem of poplar trees with its highly organized secondary xylem enables the boundaries between different developmental zones to be easily distinguished. This property of wood-forming tissues allowed us to determine a unique tissue-specific transcript profile for a well defined developmental gradient. RNA was prepared from different developmental stages of xylogenesis for DNA microarray analysis by using a hybrid aspen unigene set consisting of 2,995 expressed sequence tags. The analysis revealed that the genes encoding lignin and cellulose biosynthetic enzymes, as well as a number of transcription factors and other potential regulators of xylogenesis, are under strict developmental stage-specific transcriptional regulation.
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| 15. |
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| 16. |
- Nilsson, K.Peter R., et al.
(author)
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Conformational transitions in a free amino acid functionalized polythiophene
- 2003
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In: Synthetic metals. - : Elsevier. - 0379-6779 .- 1879-3290. ; 135-136, s. 291-292
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Journal article (peer-reviewed)abstract
- A chiral, 3-substituted polythiophene with an amino acid function shows pH-dependent visible, emission and circular dichroism spectra in buffered aqueous solution. At pH equal to pi of the amino acid, the backbone adopts a non-planar right-handed helical conformation and the polymer chains are separated from each other. Increasing pH leads to a more planar conformation of the backbone and an aggregation of the polymer chains occurs. A lower pH will also lead to a more planar conformation of the backbone, but aggregation of the polymer chains appears to be absent. © 2003 Elsevier Science B.V. All rights reserved.
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| 17. |
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| 18. |
- Schrader, J., et al.
(author)
-
Cambial meristem dormancy in trees involves extensive remodelling of the transcriptome
- 2004
-
In: The Plant Journal. - Malden : Wiley-Blackwell. - 0960-7412 .- 1365-313X. ; 40:2, s. 173-187
-
Journal article (peer-reviewed)abstract
- The establishment of the dormant state in meristems involves considerable physiological and metabolic alterations necessary for surviving unfavourable growth conditions. However, a global molecular analysis of dormancy in meristems has been hampered by the difficulty in isolating meristem cells. We used cryosectioning to isolate purified cambial meristem cells from the woody plant Populus tremula during active growth and dormancy. These samples were used to generate meristem-specific cDNA libraries and for cDNA microarray experiments to define the global transcriptional changes underlying cambial dormancy. The results indicate a significant reduction in the complexity of the cambial transcriptome in the dormant state. Although cell division is terminated in the dormant cambium, the cell cycle machinery appears to be maintained in a skeletal state as suggested by the continued presence of transcripts for several cell cycle regulators. The downregulation of PttPIN1 and PttPIN2 transcripts explains the reduced basipetal polar auxin transport during dormancy. The induction of a member of the SINA family of ubiquitin ligases implicated in auxin signalling indicates a potential mechanism for modulation of auxin sensitivity during cambial dormancy. The metabolic alterations during dormancy are mirrored in the induction of genes involved in starch breakdown and the glyoxysomal cycle. Interestingly, the induction of RGA1 like gene suggests modification of gibberellin signalling in cambial dormancy. The induction of genes such as poplar orthologues of FIE and HAP2 indicates a potential role for these global regulators of transcription in orchestrating extensive changes in gene expression during dormancy.
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| 19. |
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| 20. |
- Svensson, Glenn, et al.
(author)
-
Mating disruption in Agrotis segetum monitored by harmonic radar
- 2001
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In: Entomologia Experimentalis et Applicata. - : Wiley. - 1570-7458 .- 0013-8703. ; 101:2, s. 111-121
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Journal article (peer-reviewed)abstract
- The long-range, pheromone-mediated, flight behaviour of male moths under natural and mating disruption conditions was monitored by means of harmonic radar. Individual male turnip moths, Agrotis segetum (Denis & Schiffermüller) (Lepidoptera: Noctuidae), tagged with radar transponders, were released and tracked in plots with or without disruptive doses of sex pheromone. In addition, male attraction to pheromone-baited traps and mating of calling females in treated and untreated plots was investigated. High doses of a four-component pheromone blend reduced trap catch by 79% and mating of females by 62% when compared with control plots in pre-radar experiments. Surprisingly, this effect was not associated with any pronounced differences in flight behaviour of males between a treatment and a control plot as revealed by harmonic radar recordings. In total, 20 flight tracks from a control plot and 22 flight tracks from a treatment plot were analysed. Moths could be followed for up to 77 min, corresponding to a track length of 7350 m. Mean ground speed ranged from 0.7 m s1 to 5.4 m s1. There was a strong trend (P = 0.06) for a greater number of male orientations to traps from downwind in the control field compared to the treatment field. Many flight tracks were fragmented due to radar shadow. Advantages and constraints using harmonic radar to study the pheromone-mediated flight behaviour of nocturnal moths are discussed.
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