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- Liljemalm, Rickard, 1982-
(författare)
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Infrared Laser Stimulation of Cerebral Cortex Cells - Aspects of Heating and Cellular Responses
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The research of functional stimulation of neural tissue is of great interest within the field of clinical neuroscience to further develop new neural prosthetics. A technique which has gained increased interest during the last couple of years is the stimulation of nervous tissue using infrared laser light. Successful results have been reported, such as stimulation of cells in both the central nervous system, and in the peripheral nervous system, and even cardiomyocytes. So far, the details about the stimulation mechanism have been a question of debate as the mechanism is somewhat hard to explain. The mechanism is believed to have a photo-thermal origin, where the light from the laser is absorbed by water, thus increasing the temperature inside and around the target cell. Despite the mechanism questions, the technique holds several promising features compared to traditional electrical stimulation. Examples of advantages are that it is contact free, no penetration is needed, it has high spatial resolution and no toxic electrochemical byproducts are produced during stimulation. However, since the laser pulses locally increase the temperature of the tissue, there is a risk of heat induced damage. Therefore, the effect of increased temperatures must be investigated thoroughly. One method of examining the changes in temperature during stimulation is to model the heating.This thesis is based on the work from four papers with the main aim to investigate and describe the response of heating, caused by laser pulses, on central nervous system cells. In paper one, a model of the heating during pulsed laser stimulation is established and used to describe the dynamic temperature changes occurring during functional stimulation of cerebral cortex cells. The model was used in all four papers. Furthermore, single cell responses, as action potentials, as well as network responses, as activity inhibition, were observed. In paper two, the response of rat astrocytes exposed to laser induced hyperthermia was investigated. Cellular migration was observed and the migration limit was used to calculate the kinetic parameters for the cells, i.e., the reaction activation energy, Ea (321.4 kJ⋅mol-1), and the frequency factor, Ac (9.47 x 1048 s-1). Furthermore, a damage signal ratio (DSR) for calculating a threshold for cellular damage was defined, and calculated to six percent. In paper three, the response of hyperthermia to cerebral cortex cells was investigated, in the same way as in the second paper. Fluorescence staining of the metabolic activity was used to reveal the heat response, and by using the limit of the observed increased fluorescence the kinetic parameters, Ea (333.6 kJ⋅mol-1), and Ac (9.76 x 1050 s-1), were calculated. The DSR for the cells was calculated to five percent. In paper four, the behavior of action potentials triggered by laser stimulation was investigated. More specifically, the time delay from the start of a laser pulse to the detection of an action potential, delta-t, were investigated. Two different behaviors for the initial action potentials were observed: fast decreasing delta-t and slow decreasing delta-t. The results show the dynamic behavior of action potential responses to infrared light.The work of this thesis show the dynamic changes of the temperature during optical stimulation, using an infrared laser working at 1,550 nanometers. It also shows how the changes cause astrocytes to migrate for pulses several seconds long, and neurons to fire action potentials for pulses in the millisecond range. Furthermore, a damage signal ratio was defined and calculated for the cell systems.
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| 2. |
- Marklund, Sarah, et al.
(författare)
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To act or not to act - a sense of control is important for people with chronic obstructive pulmonary disease to increase physical activity : grounded theory study
- 2023
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Ingår i: JMIR Formative Research. - : JMIR Publications. - 2561-326X. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Background: Among people with chronic obstructive pulmonary disease (COPD), low level of daily physical activity (PA) is the main risk factor for developing cardiovascular, metabolic, and musculoskeletal comorbidities. Increasing PA in people with COPD is complex as PA behavior itself is complex and multifaceted, including personal, physiological, and psychologicalelements as well as social and environmental factors. Although eHealth solutions such as web-based support or websites haveshown positive effects on PA in people with COPD, the results are inconclusive, and it is still unclear how eHealth solutionsmight be used to support positive changes in PA behavior in people with COPD.Objective: This study aimed to explore the perceptions of increasing objective PA when using a web-based eHealth tool amongpeople with COPD.Methods: This study was part of a pragmatic randomized controlled trial with in-depth interviews between the 3- and 12-month follow-ups. The methodology used was constructivist grounded theory. All sampling included participants from the randomized controlled trial intervention group, that is, participants who had access to the eHealth tool in question and agreed to be contacted for an in-depth interview. Inclusion of participants continued until data saturation was reached, resulting in an inclusion of 14 (n=8, 57% women) participants aged between 49 and 84 years and living in 8 municipalities in Middle and Northern Sweden. Two interviews were conducted face-to-face, and the remaining interviews were conducted via telephone. All interviews were recorded using a Dictaphone.Results: The analysis resulted in 3 main categories: welcoming or not welcoming action, having or lacking resources, and lowering the threshold. The first 2 categories contain barriers and facilitators, whereas the third category contains only facilitators. The categories lead to the more latent theme Perceiving enough control to enable action, meaning that it seems that perceiving the right amount of control is essential to maintain or increase the level of PA when using an eHealth tool, among patients with COPD. However, the right amount of control seemed to depend on the individual (and context) in question.Conclusions: The core category indicates that a need for a certain sense of control was interpreted as necessary for increasing the PA level as well as for using an eHealth tool to help increase the PA level. The eHealth tool seemed to strengthen or weaken the perception of control by either providing support or by being too demanding on the user. Perceptions varied depending onother environmental factors. The Fogg Behavior Model illustrated how motivational levels, ability levels, and functional triggers interact within our findings. Thus, this study provides further evidence for the importance of empowering the patients to boost their level of agency and their ability to improve PA levels.
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| 3. |
- Nyberg, Andre, Docent, 1984-, et al.
(författare)
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KOLwebben ökar kunskapen hos både personer med KOL och personal
- 2023
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Ingår i: Fysioterapi. - : Fysioterapeuterna. - 1653-5804. ; :1, s. 30-35
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Forskningsöversikt (populärvet., debatt m.m.)abstract
- I ett försök att minska gapet mellan rådande riktlinjer gällande icke-farmakologiska interventioner och den vård som erbjuds till personer med KOL har vi, tillsammans med användare, utvecklat och utvärderat KOLwebben. Användning av KOLwebben ledde till en kliniskt relevant ökad fysisk aktivitetsnivå och en ökad kunskap om egenvårdsstrategier hos personer med KOL. Hälso- och sjukvårdspersonal i regional primärvård och kommunal hemsjukvård rapporterade ökad kunskap om sjukdomen, behandlingsmetoder, arbetssätt och att verktyget är ett stöd i deras arbete. Initialt krävs dock extra resurser i form av tid och rutiner för att implementering ska ske. Ett digitalt stöd som KOLwebben kan rekommenderas till personer som är motiverade till att använda e-hälsoverktyg och som har en tillräcklig förmåga att ta till sig information om sin hälsa.
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