| 1. |
- Andersson, Ingemar, 1950-
(författare)
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Rehabilitering vid långvarig smärta
- 2010. - 2
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Ingår i: Smärta och smärtbehandling. - Stockholm : Liber. - 9789147084135 ; , s. 401-409
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Aupée, Anne-Marie, et al.
(författare)
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Age-related changes of phasic heart rate responses to affective pictures
- 2008
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Ingår i: Scandinavian Journal of Psychology. - : Wiley-Blackwell. - 0036-5564 .- 1467-9450. ; 49:4, s. 325-331
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Tidskriftsartikel (refereegranskat)abstract
- This study examined age differences in phasic heart rate in response to neutral, negative and positive pictures. Heart rate changes and subjective ratings were analyzed in 22 middle-aged (40-55 years) and 30 older (56-78 years) participants. The effects of valence on the HR pattern across time were similar to that obtained by Bradley and co-workers. Conversely to previous studies, we did not report any age-related reduction in cardiac reactivity. Instead, when viewing positive pictures, the triphasic wave form appeared in the group of older adults, but for younger participants, it was replaced by a sustained deceleration. These results were interpreted in the light of the socioemotional selectivity theory.
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| 3. |
- Barclay, C J, et al.
(författare)
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Initial mechanical efficiency of isolated cardiac muscle
- 2003
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Ingår i: Journal of Experimental Biology. - 0022-0949 .- 1477-9145. ; 206:Pt 16, s. 2725-32
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to determine whether the initial mechanical efficiency (ratio of work output to initial metabolic cost) of isolated cardiac muscle is over 60%, as has been reported previously, or whether it is approximately 30%, as suggested by an estimate based on the well-established net mechanical efficiency (ratio of work output to total, suprabasal energy cost) of 15%. Determination of initial efficiency required separation of the enthalpy output (i.e. heat + work) into initial and recovery components. The former corresponds to energy produced by reactions that use high-energy phosphates and the latter to energy produced in the regeneration of high-energy phosphates. The two components were separated mathematically. Experiments were performed in vitro (30 degrees C) using preparations dissected from rat left ventricular papillary muscles (N=13). Muscle work output and heat production were measured during a series of 40 contractions using a contraction protocol designed to mimic in vivo papillary muscle activity. Net mechanical efficiency was 13.3+/-0.7%. The total enthalpy output was 2.16 times greater than the initial enthalpy output, so that initial mechanical efficiency was 28.1+/-1.2%.
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| 4. |
- Bredie, Wender L. P., et al.
(författare)
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A comparative study on facially expressed emotions in response to basic tastes
- 2014
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Ingår i: Chemosensory Perception. - 1936-5802. ; 7:1, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Facially expressed emotions play a role in communication between individuals. They form another means of expressing oneself besides verbal expressions or self-reporting of feelings and perceptions on psychometric scales and are implicit in nature. This study aimed to evaluate the extent and specificity of evoking facial expressed emotions by basic tastes and to evaluate if facially expressed emotions provide additional information to explicit measures. The emotions were characterised upon tasting the five basic tastes in aqueous solutions at three different concentrations levels. The sensory and emotional responses reported were obtained from a 21-membered taste panel. Facial reactions and facially expressed emotions depended on the taste quality and taste intensity. However, the facially expressed emotions were generally weak even for the relatively strong taste intensities. Bitter (caffeine), sour (citric acid) and salty (sodium chloride) lead to clear disgust and surprise responses, whereas, sweet (sucrose) and umami (glutamic acid monosodium salt) taste gave weakly noticeable facially expressed emotions. Although correlations between the expressed emotions and hedonic responses were observed, the affective experience had a limited predictive ability for the facially expressed emotion at the individual level. In conclusion, psychometric rating of the hedonic response is easier to assess than facially expressed emotions although it may not completely represent the dimensions of the emotional experience.
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| 5. |
- Hansson-Sandsten, Maria, et al.
(författare)
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Multiple window correlation analysis of HRV power and respiratory frequency
- 2007
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Ingår i: IEEE Transactions on Biomedical Engineering. - 0018-9294 .- 1558-2531. ; 54:10, s. 1770-1779
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we evaluate the correlation estimate, based on multiple window spectrum analysis, between the respiratory center frequency and the high-frequency band of the heartrate variability (HRV) power. One aim is to examine whether a more restricted frequency range would better capture respiratory related HR variation, especially when the HR variation is changing rapidly. The respiratory peak is detected and a narrow-banded measure of the high-frequency (HF) band of the HRV is defined as the respiratory frequency +/-0.05 Hz. We compare the mean square error of the correlation estimate between the frequency of the respiratory peak and the power of the HRV with the power in the usual 0.12-0.4 Hz frequency band. Different multiple window spectrum techniques are used for the estimation of the respiratory frequency as well as for the power of the HRV. We compare the peak-matched multiple windows with the Welch method while evaluating the two different HF-power estimates mentioned above. The results show that using a more narrow band for the power estimation gives stronger correlation which indicates that the estimate of the power is more robust.
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| 6. |
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| 7. |
- Jönsson, Peter, et al.
(författare)
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Cardiovascular and cortisol reactivity and habituation to a virtual reality version of the Trier Social Stress Test : a pilot study
- 2010
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Ingår i: Psychoneuroendocrinology. - : Elsevier. - 0306-4530 .- 1873-3360. ; 35:9, s. 1397-1403
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Tidskriftsartikel (refereegranskat)abstract
- The Trier Social Stress Test (TSST) is a widely used protocol to induce stress in laboratory settings. Briefly, in the TSST, the test participant is asked to hold a speech and to do an arithmetic task in front of an audience. In the present pilot study, we examined endocrine and autonomic reactivity and habituation to repeated stress provocations using a virtual reality (VR) version of TSST. The VR system was a CAVE™ system with three rear projected walls (4 m×3 m), and one floor projection. The system also included a head tracking system and passive stereoscopy. The virtual audience consisted of one woman, and two men. Ten healthy men, mean age 28.3 years (24-38 years), were confronted with the test twice (1 week between sessions), during which salivary cortisol, heart rate (HR), high frequency heart rate variability (HF-HRV, parasympathetic activity), and T-wave amplitude (TWA, suggested to be related to sympathetic influence on myocardial performance) were assessed. Cortisol secretion showed a marked increase (88% vs. baseline) during the first stress provocation, but habituated in the second session. The magnitude of HR and TWA reactivity during stress provocation was approximately the same at both sessions, implying a stable increase in sympathetic activity. Heart rate showed a maximum increase of 40% at the first session, and 32% at the second. TWA showed a maximum decrease of 42% at the first session, and 39% at the second. The results resemble those obtained in prior studies using the real-life TSST. If these results can be replicated with larger samples, VR technology may be used as a simple and standardized tool for social stress induction in experimental settings.
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| 8. |
- Widén, Cecilia, et al.
(författare)
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ATP splitting by half the cross-bridges can explain the twitch energetics of mouse papillary muscle
- 2006
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Ingår i: Journal of Physiology. - 0022-3751 .- 1469-7793. ; 573:Pt 1, s. 5-15
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to quantify the fraction of cross-bridges that cycle during a cardiac twitch. Measurements of the energetics of contracting left ventricular mouse papillary muscle were made in vitro (27 degrees C) using the myothermic technique. Enthalpy output was partitioned into force-dependent and force-independent components using 2,3-butanedione monoxime (BDM) to selectively inhibit cross-bridge cycling. For isometric contractions and a contraction frequency of 2 Hz the net enthalpy output was 5.7 +/- 0.8 mJ g(-1) twitch(-1) and initial enthalpy output was 2.3 +/- 0.3 mJ g(-1) twitch(-1) (n = 11). Assuming that low concentrations of BDM did not affect Ca2+ cycling, force-independent enthalpy output was 18.6 +/- 1.9% (n = 7) of the initial enthalpy output. Enthalpy output decreased with increased contraction frequency but was independent of shortening velocity. On the basis of these values, it was calculated that the twitch energetics were consistent with ATP splitting by half the cross-bridges and the pumping of one Ca2+ into the sarcoplasmic reticulum for every three cross-bridge cycles. The simplest interpretation is that half the cross-bridges completed one ATP-splitting cycle in each twitch. The lack of influence of shortening velocity on energy cost supports the idea that the amount of energy to be used is determined early in a twitch and is not greatly influenced by events that occur during the contraction.
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| 9. |
- Widén, Cecilia, et al.
(författare)
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Resting metabolism of mouse papillary muscle
- 2005
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Ingår i: Pflügers Archiv. - 0031-6768 .- 1432-2013. ; 450:4, s. 209-16
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Tidskriftsartikel (refereegranskat)abstract
- The aims of this study were to measure the resting metabolic rate of isolated mouse papillary muscles and to determine whether diffusive O2 supply is adequate to support the resting metabolism. Resting metabolism of left ventricular papillary muscles was measured in vitro (27 degrees C) using the myothermic technique. The rate of resting metabolism declined exponentially with time towards a steady value, with a time constant of 18+/-2 min (n=13). There was no alteration in isometric force output during this time. The magnitude of the resting metabolism, which depended inversely on muscle mass, more than doubled following a change in substrate from glucose to pyruvate and was increased 2.5-fold when the osmolarity of the bathing solution was increased by addition of 300 mM sucrose. Addition of 30 mM 2, 3-butanedione monoxime affected neither the time course of the decline in metabolic rate nor the eventual steady value. Analysis of the diffusive oxygen supply to the isolated preparation indicated that small papillary muscles (mass <1 mg), which have a very high resting metabolic rate early in an experiment, are unlikely to be adequately oxygenated.
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| 10. |
- Önning, Gunilla, et al.
(författare)
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Intake of Lactobacillus plantarum HEAL9 reduces the inflammatory markers soluble fractalkine and CD163 during acute stress : a randomized, double blind, placebo-controlled study
- 2020
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Ingår i: Physiology and Behavior. - 0031-9384 .- 1873-507X. ; 225
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Tidskriftsartikel (refereegranskat)abstract
- The intestine and the brain are connected via the brain-gut axis and the intestinal microbiota influences the immune activation and signaling molecules that are involved in the stress response. The aim of the study was to investigate if intake of the probiotic strain Lactobacillus plantarum HEAL9 (LPHEAL9) for four weeks could counteract elevated cortisol and inflammation levels in subjects with chronic stress that are exposed to an acute stress test (Trier Social Stress Test, TSST). Seventy participants were included, and 63 participants completed the study (LPHEAL9, n=32; placebo, n=31). Cardiovascular reactivity and cortisol levels were affected by the TSST, but no differences between the groups were observed. Intake of LPHEAL9 did, however, result in significantly decreased plasma levels of two inflammatory markers (soluble fractalkine and CD163) compared to placebo. In conclusion, intake of LPHEAL9 for four weeks may reduce inflammatory markers coupled to acute stress in chronically stressed individuals.
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