| 1. |
- Klintenäs, Maria
(author)
-
Regulation of phenology and the juvenility-to-maturity transition in trees
- 2012
-
Doctoral thesis (other academic/artistic)abstract
- The juvenile reproductive phase refers to the period when young plants are unable to respond to inductive environmental signals to induce flowering. The length of this phase varies considerably between different species. In annuals, e.g., Arabidopsis, the juvenile phase is typically very short, whereas in perennials, e.g., hybrid aspen, it is several years. Apart from juvenile and mature reproductive phases, the plant can also display juvenile and mature vegetative phases, distinguished by morphological changes in growth pattern, leaf shape, trichome distribution, etc. miR156 is a primary regulator of the juvenile phase in Arabidopsis, whereas TEMPRANILLO (TEM) plays a more minor but still important role in regulating the length of the juvenile phase in Arabidopsis. In the work described in this thesis, I investigated the function of the closest Populus homologs of both miR156 and TEM in hybrid aspen with respect to their involvement in regulating the juvenile vegetative phase in Populus as well as their effects on phenology. The results showed that miR156 regulates the juvenile vegetative phase in Populus as hybrid aspen overexpressing PttmiR156e exhibits a severely prolonged juvenile phase. In addition, both PttmiR156e and the TEM homologs PttRAV1 and PttRAV2 affect sylleptic branching, possibly by changing the dormancy of the axillary bud. Interestingly, they also affect bud set. This indicates that similar genetic pathways are involved in the control of aging and phenology in Populus. I also studied the biochemical evolution of the angiosperm FT lineage. My data show that FT-like genes are absent in gymnosperms and suggests that the FT-like function emerged at an early stage during the evolution of flowering plants as a means to regulate flowering time.
|
|
| 2. |
- Aad, G., et al.
(author)
-
- 2012
-
swepub:Mat__t (peer-reviewed)
|
|
| 3. |
- Huč, Sabina, 1987-, et al.
(author)
-
Numerical analysis of moisture-induced strains and stresses in glued-laminated timber
- 2020
-
In: Holzforschung. - : Walter de Gruyter. - 0018-3830 .- 1437-434X. ; 74:5, s. 445-457
-
Journal article (peer-reviewed)abstract
- Changes in relative humidity of the ambient air, RH (%), cause wetting and drying of wood material, which results in non-uniform moisture contents or moisture gradients, and consequently in moisture-induced stresses and strains in the glued-laminated timber (glulam) members. The aim of the present paper is to perform a hygromechanical analysis to predict the mechanical behavior of glulam specimens exposed to two RH regimes, causing wetting from 50% to 90% RH and drying from 90% to 50% RH, and compare the numerical to the experimental results. The aims are also to quantitatively analyze the influence of characteristic material parameters required in the multi-Fickian moisture transport model and the mechanical model on moisture-induced strains and stresses in glulam specimens and to determine the possibility of cracking of the material by analyzing the maximum tensile stresses perpendicular to the grain. Accurate numerical predictions of moisture contents and moisture-induced strains are obtained in the glulam specimens during wetting and drying as compared to the experimental results. The influence of a particular characteristic material parameter on moisture-induced strains and stresses is characterized as significant, but not crucial when a rough numerical estimation of the mechanical behavior of the glulam beam exposed to RH changes is required.
|
|
| 4. |
|
|
| 5. |
- Faxälv, Lars, et al.
(author)
-
Imaging of blood plasma coagulation and its propagation at surfaces.
- 2008
-
In: Journal of biomedical materials research. Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 85:4, s. 1129-34
-
Journal article (peer-reviewed)abstract
- A new method utilizing image capture and processing was developed for the analysis of blood plasma coagulation at surfaces. The coagulation was detected in a cuvette by time-lapse image capture of light scattering from the developing fibrin network. By image processing and computer analysis of the captured image data, both early detection of coagulation at the surface and the propagation phase of coagulation could be measured in the same experiment. It is possible to use both platelet-rich plasma (PRP) and platelet-free plasma (PFP) with the method, and thereby study the platelet contribution to both surface coagulation and propagation of coagulation. Two well-known model surfaces, hydrophilic and hydrophobic glass, were used in combination with PRP and PFP to illustrate the method. Hydrophilic glass activated coagulation significantly faster (PRP: 7.0 +/- 1.7 min, PFP: 5.9 +/- 1.2 min, n= 16) than hydrophobic glass (PRP: 50 +/- 14 min, PFP: 65 +/- 32 min, n = 16) in both PRP and PFP. Hydrophilic surfaces showed a faster initial propagation of coagulation adjacent to the surface (mean velocity: 0.14 +/- 0.05 mm/ minute) compared with the propagation observed further out from the surface (mean velocity: 0.05 +/- 0.01 mm/min). The method is very flexible and can be suitable for screening hemocompatibility of biomaterials.
|
|
