| 1. |
|
|
| 2. |
- Alzubaidi, H., et al.
(författare)
-
Statistical Analysis of Gravel Road Rating
- 2002
-
Ingår i: The international journal of pavement engineering. - Nottingham. - 1029-8436 .- 1477-268X. ; 3:1, s. 35-42
-
Tidskriftsartikel (refereegranskat)
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
- Engström, Björn, et al.
(författare)
-
Anchorage and bond in high strenght concrete
- 2000
-
Ingår i: Bond of reinforcement in concrete. - Lausanne : International Federation for Structural Concrete / Task Group Bond Models. - 2883940509 ; , s. 99-156
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
|
|
| 6. |
|
|
| 7. |
- Fransson, Per-Anders, et al.
(författare)
-
Analysis of Postural Control Adaptation during Galvanic and Vibratory Stimulation
- 2001
-
Ingår i: Proc. 23rd Annual EMBS International Conference (EMBC2001). ; , s. 1170-1173
-
Konferensbidrag (refereegranskat)abstract
- The objective for this study was to investigate whether the postural control adaptation during galvanic stimulation of the vestibular nerve were similar to that found during vibration stimulation to the calf muscles. A method for adaptation analysis was used to analyze the evoked changes of posture, stimulus responses and the motion dynamics. The adaptive adjustments of postural control were similar during galvanic and vibratory stimulation, which suggests that the adaptation operate in the same way independent of the receptor systems affected by the disturbance. There was however a difference in the dynamic feedback properties of the measured responses.
|
|
| 8. |
- Fransson, Per-Anders, et al.
(författare)
-
Analysis of Short- and Long-Term Effects of Adaptation in Human Postural Control
- 2002
-
Ingår i: Biological Cybernetics. - : Springer Science and Business Media LLC. - 1432-0770 .- 0340-1200. ; 86:5, s. 355-365
-
Tidskriftsartikel (refereegranskat)abstract
- The short-term (i.e., days) and long-term (i.e., months) effects of adaptation to posturography examinations were investigated in 12 normal subjects who were repeatedly examined for five consecutive days and again after 90 days. The examinations were conducted both with eyes open and closed, and the perturbations were evoked by a pseudorandomly applied vibration stimulation to the calf muscles. The evoked anteroposterior responses were analyzed with a method considering adaptation in the slow changes in posture and in the stimulus-response relationship. Repetition of examinations on a daily basis revealed a gradual improvement of postural-control performance. The body sway induced by the stimulation was significantly reduced and the dynamical properties changed. Most of the improvements remained after 90 days, but some parameters such as the complexity of the control system used were increased to the initial level. The results confirm previous observations that postural control contains several partially independent adaptive processes, observed in terms of alteration of posture and as a progressive reduction of body sway induced by stimulation. The method used for the adaptation analysis in this study could be applied to analyze biological systems with multiple individual adaptive processes with different time courses or characteristics, or where the adaptation processes are related to multiple internal or external factors.
|
|
| 9. |
- Fransson, Per-Anders, et al.
(författare)
-
Balance Control and Adaptation during Vibratory Perturbations in Middle-Aged and Elderly Humans.
- 2004
-
Ingår i: European Journal of Applied Physiology. - : Springer Science and Business Media LLC. - 1439-6327 .- 1439-6319. ; 91:5-6, s. 595-603
-
Tidskriftsartikel (refereegranskat)abstract
- The objective was to investigate if healthy elderly people respond and adapt differently to postural disturbances compared to middle-aged people. Thirty middle-aged (mean age 37.8 years, range 24–56 years) and forty healthy elderly subjects (mean age 74.6 years, range 66–88 years) were tested with posturography. Body sway was evoked by applying pseudorandom vibratory stimulation to the belly of the gastrocnemius muscles of both legs simultaneously. The tests were performed both with eyes open and eyes closed. The anteroposterior body sway was measured with a force platform and analyzed with a method that considers the adaptive changes of posture and stimulation responses. The results showed that middle-aged people generally used a different postural control strategy as compared to the elderly. The elderly responded more rapidly to vibratory perturbation, used more high-frequency (>0.1 Hz) motions and the motion dynamics had a higher degree of complexity. Moreover, the elderly had diminished ability to use visual information to improve balance control. Altogether, despite having an effective postural control adaptation similar to that of middle-aged people, the elderly had more difficultly in withstanding balance perturbations. These findings suggest that the balance control deterioration associated with aging cannot be fully compensated for by postural control adaptation.
|
|
| 10. |
- Fransson, Per-Anders, et al.
(författare)
-
Methods for Evaluation of Postural Control Adaptation
- 2000
-
Ingår i: Gait & Posture. - 1879-2219. ; 12:1, s. 14-24
-
Tidskriftsartikel (refereegranskat)abstract
- New methods were developed to determine the dynamic changes of postural control during the initial exposure to large perturbances of stance. The adjustments of postural control over time in measured anteroposterior torque, were investigated in ten normal subjects. Perturbations of stance were evoked by two high intensity vibrators applying pseudorandom stimulation either to the calf muscles or the paravertebral muscles of the neck. The new methods use a system identification approach, which distinguishes between feedback control, adaptation of postural responses and adaptation to stimulus. This approach makes it possible to quantify motion dynamics and complexity, stimulus impact and adjustments of postural control. Quantification of the different adaptive responses could be useful for diagnostic purposes, in evaluating treatment efficacy and patient progress in rehabilitation programs.
|
|
| 11. |
- Fransson, Per-Anders, et al.
(författare)
-
Postural Control Adaptation during Galvanic Vestibular and Vibratory Proprioceptive Stimulation
- 2003
-
Ingår i: IEEE Transactions on Biomedical Engineering. - 1558-2531. ; 50:12, s. 1310-1319
-
Tidskriftsartikel (refereegranskat)abstract
- he objective for this study was to investigate whether the adaptation of postural control was similar during galvanic vestibular stimulation and during vibratory proprioceptivestimulation of the calf muscles. Healthy subjects were tested during erect stance with eyes open or closed. An analysis method designed to consider the adaptive adjustments was used to evaluate the motion dynamics and the evoked changes of posture and stimulation response.Galvanic vestibular stimulation induced primarily lateral body movements and vibratory proprioceptive stimulation induced anteroposterior movements. The lateral body sway generated by the galvanic stimulation was proportionally smaller and contained more high-frequency movements (0.1 Hz) than the anteroposterior body sway induced by the vibratory stimulation. The adaptive adjustments of the body sway to the stimulation had similar time course and magnitude during galvanic and vibratory stimulation. The perturbations induced by stimulation were gradually reduced within the same time range (15–20 s) and both kinds of stimulation induced a body leaning whose direction was dependent on stimulus. The similarities in the adjustmentpatterns suggest that postural control operates in the same way independent of the receptor systems affected by the disturbance and irrespective of whether the motion responses were induced in a lateral or anteroposterior direction.
|
|
| 12. |
- Johansson, Rolf, et al.
(författare)
-
Identification of Adaptation in Human Postural Control using GARCH Models
- 2001
-
Ingår i: Proceedings of the 40th IEEE Conference on Decision and Control, 2001.. - 0780370619 ; 1, s. 7-12
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Human postural dynamics was investigated in twelve normal subjects by means of a force platform recording body sway induced by bipolar transmastoid galvanic stimulation of the vestibular nerve and labyrinth. We modeled the stabilizing forces actuated by the feet as resulting from complex muscular activity subject to feedback of body velocity and position. Time series analysis demonstrated that a transfer function from stimulus to sway-force response with specific parameters could be identified. In addition, adaptation to the vestibular stimulus was demonstrated to exist. Residual GARCH modeling (generalized autoregressive conditional heteroskedasticity) suggested a postural adaptation time constant in the range of 40-50 s. The results suggest means to evaluate adaptive behavior in postural control and in other physiological contexts
|
|
| 13. |
- Johansson, Rolf, et al.
(författare)
-
Multi-Stimulus Multi-Response Posturography
- 2001
-
Ingår i: Mathematical Biosciences. - 0025-5564. ; 174:1, s. 41-59
-
Tidskriftsartikel (refereegranskat)abstract
- In this study a method for the analysis of simultaneous multiple measurements of kinematics and stabilizing forces related to human postural dynamics is proposed. Each subject in a group of normal subjects (n=10) was tested with eyes-open and eyes-closed with simultaneous but uncorrelated vestibular and proprioceptive stimuli in order to investigate the contributions of individual sensory feedback loops. Statistical analysis was made by means of multi-input multi-output identification of a transfer function from stimuli to stabilizing forces of the feet and the resulting body position, the transfer function being compatible with a biomechanical model formulated as a stabilized segmented inverted pendulum subject to feedback of body sway and position. Each individual model estimated is effective in predicting a subject's response to new stimuli and in describing the interacting effects of stimuli on body kinetics. The proposed methodology responds to the current needs of data analysis of multi-stimulus multi-response experiments.
|
|
| 14. |
|
|
| 15. |
|
|
| 16. |
|
|
| 17. |
|
|
| 18. |
|
|
| 19. |
|
|
| 20. |
|
|
| 21. |
|
|
| 22. |
- Tågerud, Sven, et al.
(författare)
-
The nifk gene is widely expressed in mouse tissues and is up-regulated in denervated hind limb muscle
- 2003
-
Ingår i: Cell Biology International. - 1065-6995 .- 1095-8355. ; 27:6, s. 469-475
-
Tidskriftsartikel (refereegranskat)abstract
- Denervation of skeletal muscle alters the expression of many genes, which may be important for establishing optimal conditions for reinnervation. Using the differential display technique we have attempted to discover neurally regulated genes in skeletal muscle. An mRNA that is up-regulated in denervated hind limb muscle was identified and cloned. The cDNA encodes an RNA-binding protein, which was discovered during the course of this work to be a nucleolar protein interacting with the fork-head associated domain of the proliferation marker protein Ki-67, and named NIFK. We show that the nifk gene is widely expressed in adult mouse tissues and that the expression is up-regulated in denervated hind limb muscle. No difference between expression in perisynaptic and extrasynaptic portions of muscle was observed. The widespread expression in adult tissues suggests that the NIFK protein has other functions in addition to its interaction with Ki-67, which is only expressed in proliferating cells.
|
|
