| 1. |
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| 2. |
- Björkman, Frida, et al.
(författare)
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Regular moist snuff dipping does not affect endurance exercise performance
- 2017
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 12:7
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Tidskriftsartikel (refereegranskat)abstract
- Physiological and medical effects of snuff have previously been obtained either in cross-sectional studies or after snuff administration to non-tobacco users. The effects of snuff cessation after several years of daily use are unknown. 24 participants with >2 years of daily snuff-use were tested before and after >6 weeks snuff cessation (SCG). A control group (CO) of 11 snuff users kept their normal habits. Resting heart rate (HR) and blood pressure (BP) were significantly lower in SCG after snuff cessation, and body mass was increased by 1.4 +/- 1.7 kg. Total cholesterol increased from 4.12 +/- 0.54 (95% CI 3.89-4.35) to 4.46 +/- 0.70 (95% CI 4.16-4.75) mM L-1 in SCG, due to increased LDL, and this change was significantly different from CO. Resting values of HDL, C-reactive protein, and free fatty acids (FFA) remained unchanged in both groups. In SCG group, both HR and BP were reduced during a four-stage incremental cycling test (from 50 to 80% of VO(2)max) and a prolonged cycling test (60 min at 50% of VO(2)max). Oxygen uptake (VO2), respiratory exchange ratio, blood lactate (bLa) and blood glucose (bGlu) concentration, and rate of perceived exertion (RPE) were unchanged. In CO group, all measurements were unchanged. During the prolonged cycling test, FFA was reduced, but with no significant difference between groups. During the maximal treadmill running test peak values of VO2, pulmonary ventilation (VE), time to exhaustion and bLa were unchanged in both groups. In conclusion, endurance exercise performance (VO(2)dmax and maximal endurance time) does not seem to be affected by prolonged snuff use, while effects on cardiovascular risk factors are contradictory. HR and BP during rest and submaximal exercise are reduced after cessation of regular use of snuff. Evidently, the long-time adrenergic stress on circulation is reversible.
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| 3. |
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| 4. |
- Brown, Toby D, et al.
(författare)
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Melt electrospinning of poly(ε-caprolactone) scaffolds : phenomenological observations associated with collection and direct writing.
- 2014
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Ingår i: Materials science & engineering. C, biomimetic materials, sensors and systems. - : Elsevier BV. - 0928-4931 .- 1873-0191. ; 45
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Tidskriftsartikel (refereegranskat)abstract
- Melt electrospinning and its additive manufacturing analogue, melt electrospinning writing (MEW), are two processes which can produce porous materials for applications where solvent toxicity and accumulation in solution electrospinning are problematic. This study explores the melt electrospinning of poly(ε-caprolactone) (PCL) scaffolds, specifically for applications in tissue engineering. The research described here aims to inform researchers interested in melt electrospinning about technical aspects of the process. This includes rapid fiber characterization using glass microscope slides, allowing influential processing parameters on fiber morphology to be assessed, as well as observed fiber collection phenomena on different collector substrates. The distribution and alignment of melt electrospun PCL fibers can be controlled to a certain degree using patterned collectors to create large numbers of scaffolds with shaped macroporous architectures. However, the buildup of residual charge in the collected fibers limits the achievable thickness of the porous template through such scaffolds. One challenge identified for MEW is the ability to control charge buildup so that fibers can be placed accurately in close proximity, and in many centimeter heights. The scale and size of scaffolds produced using MEW, however, indicate that this emerging process will fill a technological niche in biofabrication.
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| 5. |
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| 6. |
- Cai, Yixiao, et al.
(författare)
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Strategy towards independent electrical stimulation from cochlear implants : Guided auditory neuron growth on topographically modified nanocrystalline diamond
- 2016
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Ingår i: Acta Biomaterialia. - : Elsevier BV. - 1742-7061 .- 1878-7568. ; 31, s. 211-220
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Tidskriftsartikel (refereegranskat)abstract
- Cochlear implants (CI) have been used for several decades to treat patients with profound hearing loss. Nevertheless, results vary between individuals, and fine hearing is generally poor due to the lack of discrete neural stimulation from the individual receptor hair cells. A major problem is the deliverance of independent stimulation signals to individual auditory neurons. Fine hearing requires significantly more stimulation contacts with intimate neuron/electrode interphases from ordered axonal re-growth, something current CI technology cannot provide.Here, we demonstrate the potential application of micro-textured nanocrystalline diamond (NCD) surfaces on CI electrode arrays. Such textured NCD surfaces consist of micrometer-sized nail-head-shaped pillars (size 5 5 lm2) made with sequences of micro/nano-fabrication processes, including sputtering, photolithography and plasma etching.The results show that human and murine inner-ear ganglion neurites and, potentially, neural progenitor cells can attach to patterned NCD surfaces without an extracellular matrix coating. Microscopic methods revealed adhesion and neural growth, specifically along the nail-head-shaped NCD pillars in an ordered manner, rather than in non-textured areas. This pattern was established when the inter-NCD pillar distance varied between 4 and 9 lm.The findings demonstrate that regenerating auditory neurons show a strong affinity to the NCD pillars, and the technique could be used for neural guidance and the creation of new neural networks. Together with the NCD’s unique anti-bacterial and electrical properties, patterned NCD surfaces could provide designed neural/electrode interfaces to create independent electrical stimulation signals in CI electrode arrays for the neural population.
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| 7. |
- Detta, Nicola, et al.
(författare)
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Melt electrospinning of polycaprolactone and its blends with poly(ethylene glycol)
- 2010
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Ingår i: Polymer international. - : Wiley. - 0959-8103 .- 1097-0126. ; 59:11, s. 1558-1562
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Tidskriftsartikel (refereegranskat)abstract
- Melt electrospinning is one aspect of electrospinning with relatively little published literature, although the technique avoids solvent accumulation and/or toxicity which is favoured in certain applications In the study reported, we melt-electrospun blends of poly(epsilon-caprolactone) (PCL) and an amphiphilic diblock copolymer consisting of poly(ethylene glycol) and PCL segments (PEG-block PCL) A custom-made electrospinning apparatus was built and various combinations of instrument parameters such as voltage and polymer feeding rate were investigated Pure PEG-block-PCL copolymer melt electrospinning did not result in consistent and uniform fibres due to the low molecular weight, while blends of PCL and PEG-block-PCL, for some parameter combinations and certain weight ratios of the two components, were able to produce continuous fibres significantly thinner (average diameter of ca 2 mu m) compared to pure PCL The PCL fibres obtained had average diameters ranging from 6 to 33 mu m and meshes were uniform for the lowest voltage employed while mesh uniformity decreased when the voltage was increased This approach shows that PCL and blends of PEG block-PCL and PCL can be readily processed by melt electrospinning to obtain fibrous meshes with varied average diameters and morphologies that are of interest for tissue engineering purposes.
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| 8. |
- Edin, Emil
(författare)
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Effect of Stress Relief Annealing: Part Distortion, Mechanical Properties, and Microstructure of Additively Manufactured Austenitic Stainless Steel
- 2022
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Additive manufacturing (AM) processes may introduce large residual stresses in the as-built part, in particular the laser powder bed fusion process (L-PBF). The residual stress state is an inherent consequence of the heterogeneous heating and subsequent cooling during the process. L-PBF has become renowned for its “free complexity” and rapid prototyping capabilities. However, it is vital to ensure shape stability after the component is removed from the build plate, which can be problematic due to the residual stress inducing nature of this manufacturing process. Residual stresses can be analyzed via many different characterization routes (e.g. X-ray and neutron diffraction, hole drilling, etc.), both quantitatively and qualitatively. From an industrial perspective, most of these techniques are either prohibitively expensive, complex or too slow to be implementable during the early prototyping stages of AM manufacturing.In this work a deformation based method employing a specific geometry, a so called “keyhole”-geometry, has been investigated to qualitatively evaluate the effect of different stress relief annealing routes with respect to macroscopic part deformation, mechanical properties and microstructure. Previous published work has focused on structures with open geometry, commonly referred to as bridge-like structures where the deformation required for analysis occurs during removal from the build plate. The proposed keyhole-geometry can be removed from the build plate without releasing the residual stresses required for subsequent measurement, which enables bulk manufacturing on single build plates, prior to removal and stress relief annealing. Two L-PBF manufactured austenitic stainless steel alloys were studied, 316L and 21-6-9. Tensile specimen blanks were manufactured and the subsequent heat treatments were carried out in pairs of keyhole and tensile blank. Both a contact (micrometer measurement), and a non-contact (optical profilometry) method were employed to measure the residual stress induced deformation in the keyholes. The annealing heat treatment matrix was iteratively expanded with input from the deformation analysis to find the lowest temperature at which approximately zero deformation remained after opening the structure via wire electrical discharge machining. The lowest allowable annealing temperature was sought after to minimize strength loss. After stress relief annealing at 900 ℃ for 1 hour, the 316L keyhole-geometry was considered shape stable. The lateral micrometer measurement yielded a length change of 1 µm, and a radius of 140 m (over the 22 mm top surface) was assigned from curve fitting the top surface height profiles. The complementary microstructural characterization revealed that this temperature corresponded to where the last remains of the cellular sub-grain structures disappears. Tensile testing showed that the specimen subjected to the 900 ℃ heat treatment had a marked reduction in yield stress (YS) compared to that of the as-built: 540 MPa → 402 MPa, whereas ultimate tensile strength (UTS) only reduced slightly: 595 MPa → 570 MPa. The ductility (4D elongation) was found to be ~13 % higher for the specimen heat treated at 900 ℃ than that of the as-built specimen, 76% and 67% respectively. For alloy 21-6-9 the residual stress induced deformation minimum (zero measurable deformation) was found after stress relief heat treatment at 850 ℃ for 1 hour. Slight changes in the microstructure were observable through light optical microscopy when comparing the different heat treatment temperatures. The characteristic sub-grain features associated with alloy 316L were not verified for alloy 21-6-9. Similar to the results for 316L, UTS was slightly lower for the tensile specimen subjected to the heat treatment temperature required for shape stability (850 ℃) compared to the as-built specimen: 810 MPa → 775 MPa. The measured ductility (4D elongation) was found to be approximately equal for the as-built (47%), and heat treated (48%) specimen. As-built material exhibited a YS of 640 MPa while the heat treated specimen had a YS of 540 MPa. For alloy 21-6-9, the lateral micrometer deformation measurements were compared with stress relaxation testing performed at 600 ℃, 700℃ and 800 ℃. Stress relaxation results were in good agreement with the results from the lateral deformation measurements. The study showed that for both steel alloys, the keyhole method could be successfully employed to rapidly find a suitable stress relief heat treatment route when shape stability is vital.
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| 9. |
- Edin, Emil, et al.
(författare)
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Rapid method for comparative studies on stress relief heat treatment of additively manufactured 316L
- 2022
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Ingår i: Materials Science & Engineering. - : Elsevier. - 0921-5093 .- 1873-4936. ; 847
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Tidskriftsartikel (refereegranskat)abstract
- The additive manufacturing method laser powder bed fusion (L-PBF) is known to introduce large residual stresses in the built component. Optimization of process parameters and subsequent heat treatment is crucial to relieve these residual stresses. However, many of the available tools used to analyze these residual stresses are either prohibitively expensive, or too time consuming for initial prototyping stages.A qualitative method for rapid evaluation of the effectiveness of stress relief heat treatment of L-PBF manufactured 316L has been tested. Residual stress induced distortion has been measured with contact and non-contact methods to study the effect of different stress relief heat treatment temperatures (600 – 950 °C, fixed holding time: 1 h). Over the examined temperature interval, at which deformation was measured, distinct differences were observable at each temperature with both methods. Based on the distortion, shape stability was considered reached after subjecting the test geometry to a heat treatment temperature of 900 °C for 1 hour. Complementary mechanical testing and microstructural characterization were carried out to provide a more general understanding of the implications of each heat treatment temperature. Microstructural characterization revealed that complete dissolution of the cellular sub-grain features occurred at the same temperature as where the minimum magnitude of distortion was obtained.
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| 10. |
- Edin, Emil, et al.
(författare)
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Stress relief heat treatment and mechanical properties of laser powder bed fusion built 21-6-9 stainless steel
- 2023
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Ingår i: Materials Science and Engineering A. - : Elsevier. - 0921-5093 .- 1873-4936. ; 868
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Tidskriftsartikel (refereegranskat)abstract
- In this work, the effectiveness of residual stress relief annealing on a laser powder bed fusion (L-PBF) manufactured austenitic stainless steel, alloy 21-6-9 was investigated. Residual stress levels were gauged using geometrical distortion and relaxation testing results. In the investigated temperature interval (600–850 °C), shape stability was reached after subjecting the as-built material to an annealing temperature of 850 °C for 1 h. Microstructural characterization and tensile testing were also performed for each annealing temperature to evaluate the alloy's thermal stability and the resulting tensile properties. In the as-built state, a yield strength (YS) of 640 MPa, ultimate tensile strength (UTS) of 810 MPa and 4D elongation of 47% were measured. Annealing at 850 °C for 1 h had little measurable effect on ductility (48% 4D elongation) while still having a softening effect (UTS = 775 MPa, YS = 540 MPa). From the microstructural characterization, cell-like features were observed sporadically in the annealed condition and appeared stable up until 800 °C after which gradual dissolution began, with the last remnants disappearing after subjecting the material to 900 °C for 1 h.
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| 11. |
- Edin, Fredrik, et al.
(författare)
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3-D gel culture and time-lapse video microscopy of the human vestibular nerve
- 2014
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Ingår i: Acta Oto-Laryngologica. - : Informa UK Limited. - 0001-6489 .- 1651-2251. ; 134:12, s. 1211-1218
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Tidskriftsartikel (refereegranskat)abstract
- UNLABELLED: Abstract Conclusions: Human inner ear neurons have an innate regenerative capacity and can be cultured in vitro in a 3-D gel. The culture technique is valuable for experimental investigations of human inner ear neuron signaling and regeneration.OBJECTIVES: To establish a new in vitro model to study human inner ear nerve signaling and regeneration.METHODS: Human superior vestibular ganglion (SVG) was harvested during translabyrinthine surgery for removal of vestibular schwannoma. After dissection tissue explants were embedded and cultured in a laminin-based 3-D matrix (Matrigel™). 3-D growth cone (GC) expansion was analyzed using time-lapse video microscopy (TLVM). Neural marker expression was appraised using immunocytochemistry with fluorescence and laser confocal microscopy.RESULTS: Tissue explants from adult human SVG could be cultured in 3-D in a gel, indicating an innate potential for regeneration. Cultured GCs were found to expand dynamically in the gel. Growth cone expansion and axonal Schwann cell alignment were documented using TLVM. Neurons were identified morphologically and through immunohistochemical staining.
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| 12. |
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| 13. |
- Edin, Fredrik, et al.
(författare)
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Differentiation of human neural progenitor cell-derived spiral ganglion-like neurons : a time-lapse video study
- 2014
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Ingår i: Acta Oto-Laryngologica. - : Informa UK Limited. - 0001-6489 .- 1651-2251. ; 134:5, s. 441-447
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Tidskriftsartikel (refereegranskat)abstract
- Conclusions: Human neural progenitor cells can differentiate into spiral ganglion-like cells when exposed to inner ear-associated growth factors. The phenotype bears resemblance to human sphere-derived neurons. Objective: To establish an in vitro model for the human auditory nerve to replace and complement in vivo animal experiments and ultimately human in vivo transplantation. Methods: Human neural progenitors were differentiated under conditions developed for in vitro survival of human primary spiral ganglion culture with media containing growth factors associated with inner ear development. Differentiation was documented using time-lapse video microscopy. Time-dependent marker expression was evaluated using immunocytochemistry with fluorescence and laser confocal microscopy. Results: Within 14 days of differentiation, neural progenitors adopted neural phenotype and expressed spiral ganglion-associated markers.
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| 14. |
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| 15. |
- Edin, Fredrik, 1967-
(författare)
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Därför brinner blilen
- 2013
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Ingår i: Brand. - STOCKHOLM : Brand. - 0284-9526. - 9789197787567 ; :3, s. 35-43
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 16. |
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| 17. |
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| 18. |
- Edin, Fredrik, et al.
(författare)
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Fronto-Pariatal connection asymmetry regulates working memory distractibility
- 2007
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Ingår i: Journal of Integrative Neuroscience. - 0219-6352 .- 1757-448X. ; 6:4, s. 567-596
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Tidskriftsartikel (refereegranskat)abstract
- Recent functional magnetic resonance imaging studies demonstrate that increased task-related neural activity in parietal and frontal cortex during development and training is positively correlated with improved visuospatial working memory (vsWM) performance. Yet, the analysis of the corresponding underlying functional reorganization of the fronto-parietal network has received little attention. Here, we perform an integrative experimental and computational analysis to determine the effective balance between the superior frontal sulcus (SFS) and intraparietal sulcus (IPS) and their putative role(s) in protecting against distracters. To this end, we performed electroencephalographic (EEG) recordings during a vsWM task. We utilized a biophysically based computational cortical network model to analyze the effects of different neural changes in the underlying cortical networks on the directed transfer function (DTF) and spiking activity. Combining a DTF analysis of our EEG data with the DTF analysis of the computational model, a directed strong SFS → IPS network was revealed. Such a configuration offers protection against distracters, whereas the opposite is true for strong IPS → SFS connections. Our results therefore suggest that the previously demonstrated improvement of vsWM performance during development could be due to a shift in the control of the effective balance between the SFS-IPS networks.
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| 19. |
- Edin, Fredrik, 1967-
(författare)
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Fyra mediakonspirationer utan konspiratörer
- 2018
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Ingår i: Rum för eftertanke. - Åbo : Folkets Bildningsförbund r.f.. - 9789529622153 ; , s. 134-142
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Bokkapitel (populärvet., debatt m.m.)
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| 20. |
- Edin, Fredrik, 1967-
(författare)
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Kopyright Liberation Front
- 2005
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Ingår i: Copy me. - Stockholm : Roh-nin. - 919757970X
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Bokkapitel (populärvet., debatt m.m.)
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| 21. |
- Edin, Fredrik, 1967-
(författare)
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Kronopolis : Tid, makt och medialisering i Malmö
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Syftet med den här etnografin är att undersöka hur medialiseringen påverkar stadslivet i Malmö, särskilt ur ett tidsligt perspektiv. Föremål för studien är de tidsliga maktrelationer och linjära rytmer – som arbete och konsumtion – som medialiseringen ger upphov till i det urbana rummet. Fältarbetet har genomförts i stadsdelarna Seved, Centrum, Frihamnen och Möllevången i Malmö. Studien innehåller också en reflexiv del om erfarenheterna av att bära smart klocka under fyra år. Etnografins viktigaste upptäckt är att medialiseringen gör rumsligheter och tidsligheter abstrakta och föremål för konflikt. Det här skapar en nu typ av linjära rytmer: spekulativa rytmer. Det är en ny typ av linjära rytmer som är instabila, saknar kronologisk ordning och befinner sig i ständig förändring. Potentiellt kan vilken plats som helst vara vilken annan plats som helst och vilken tid som helst, vilken annan tid som helst. Utgången av de här konflikterna är en konsekvens att de inblandade parternas respektive styrkeförhållande i varje situation. Etnografin bidrar med ett tidsligt perspektiv på medialisering och ett ökat tidsligt förstående av samhället vi lever i.
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| 22. |
- Edin, Fredrik, et al.
(författare)
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Mechanism for top-down control of working memory capacity
- 2009
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Ingår i: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 106:16, s. 6802-6807
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Tidskriftsartikel (refereegranskat)abstract
- Working memory capacity, the maximum number of items that we can transiently store in working memory, is a good predictor of our general cognitive abilities. Neural activity in both dorsolateral prefrontal cortex and posterior parietal cortex has been associated with memory retention during visuospatial working memory tasks. The parietal cortex is thought to store the memories. However, the role of the dorsolateral prefrontal cortex, a top-down control area, during pure information retention is debated, and the mechanisms regulating capacity are unknown. Here, we propose that a major role of the dorsolateral prefrontal cortex in working memory is to boost parietal memory capacity. Furthermore, we formulate the boosting mechanism computationally in a biophysical cortical microcircuit model and derive a simple, explicit mathematical formula relating memory capacity to prefrontal and parietal model parameters. For physiologically realistic parameter values, lateral inhibition in the parietal cortex limits mnemonic capacity to a maximum of 2-7 items. However, at high loads inhibition can be counteracted by excitatory prefrontal input, thus boosting parietal capacity. Predictions from the model were confirmed in an fMRI study. Our results show that although memories are stored in the parietal cortex, interindividual differences in memory capacity are partly determined by the strength of prefrontal top-down control. The model provides a mechanistic framework for understanding top-down control of working memory and specifies two different contributions of prefrontal and parietal cortex to working memory capacity.
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| 23. |
- Edin, Fredrik, 1977-
(författare)
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Neural Mechanisms Determining Visuospatial Working Memory Tasks : Biophysical Modeling, Functional MRI and EEG
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Visuospatial working memory (vsWM) is the ability to temporarily retain goal-relevant visuospatial information in memory. It is a key cognitive function related to general intelligence, and it improves throughout childhood and through WM training. Information is maintained in vsWM through persistent neuronal activity in a fronto-parietal network that consists of the intraparietal sulcus (IPS) and the frontal eye field (FEF). This network is regulated by the dorsolateral prefrontal cortex (dlPFC). The features of brain structure and activity that regulate the access to and storage capacity of visuospatial WM (vsWM) are still unknown. The aim of my doctoral work has been to find such features by combining a biophysically based model of vsWM activity with functional MRI (fMRI) and EEG experiments. In study I, we combined modeling and fMRI and showed that stronger fronto-parietal synaptic connections result in developmental increases in brain activity and in improved vsWM during development. This causal relationship was established by ruling out other previously suggested mechanisms, such as myelination or synaptic pruning, In study II, we combined modeling and EEG to further explore the connectivity of the network. We showed that FEF→IPS connections are stronger than IPS→FEF connections, and that stimuli enter IPS. This arrangement of connections prevents distracting stimuli from being stored. Study III was a theoretical study showing that errors in measurements of the amplitude of brain activity affect the estimation of effective connection strength. In study IV, we analyzed EEG data from WM training in children with epilepsy. Improvements on the trained task were accompanied by increased frontal and parietal signal power, but not fronto-parietal coherence. This indicates that local changes in FEF and IPS could underlie improvements on the trained task. dlPFC is important for the performance on a large variety of cognitive tasks. In study V, we combined modeling with fMRI to test the hypothesis that dlPFC improves vsWM capacity by providing stabilizing excitatory inputs to IPS, and that dlPFC filters distracters by specifically lowering the capacity of neurons storing distracters. fMRI data confirmed the model hypothesis. We further showed that a dysfunctional dlPFC could explain the link between vsWM capacity and distractibility, as is found in ADHD. The model suggests that dlPFC carries out its multifaceted behavior not by performing advanced calculations itself, but by providing bias signals that control operations performed in the regions it connects to. A specific aim of this thesis has been to describe the mechanistic model in a way that is accessible to people without a modeling background.
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| 24. |
- Edin, Fredrik
(författare)
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Scaling errors in measures of brain activity cause erroneous estimates of effective connectivity
- 2010
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Ingår i: NeuroImage. - : Elsevier BV. - 1053-8119 .- 1095-9572. ; 49:1, s. 621-630
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Tidskriftsartikel (refereegranskat)abstract
- Effective connectivity (EC) is the collective term for various measures of the interaction between the nodes in a network of neurons or neural populations during a certain experimental condition. Here, I investigated three types of EC that differ with respect to signal normalization, and therefore measure different aspects of neural interactions. Unnormalized EC measures pure connection strength. Amplitude-scaled EC measures the combined influence of signal amplitude and connection strength on neural activity. Finally, normalized EC measures the influence of one node on the activity of another relative to all influences on that node. With a theoretical analysis, I investigated the sensitivity of EC to signal scaling (the ratio of the amplitude of the measured signal and the underlying neural activity) and found that scaling affects the conclusions of the analysis of unnormalized EC severely, whereas normalized EC is not affected by the scaling problem. In an analysis of previously published hemodynamic response functions (Handwerker, D. A., Ollinger, J. M., D'Esposito, M., 2004. Variation of BOLD hemodynamic responses across subjects and brain regions and their effects on statistical analyses. Neuroimage 21, 1639-1651), I tested the predictions of the theoretical analysis. The empirical analysis indicated that signal scaling contributes to a large extent to measurement errors of unnormalized EC, although hemodynamic response function shape variability also contributed. Normalized EC, on the other hand, was only affected by shape differences and not by scaling. In addition to being more accurate, normalized EC is also an appropriate type of measure of neural interactivity if one is interested in the relative influence of one node on another, rather than absolute connection strengths per se.
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| 25. |
- Edin, Fredrik, 1985-
(författare)
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Strategies in Cochlear Nerve Regeneration, Guidance and Protection : Prospects for Future Cochlear Implants
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Today, it is possible to restore hearing in congenitally deaf children and severely hearing-impaired adults through cochlear implants (CIs). A CI consists of an external sound processor that provides acoustically induced signals to an internal receiver. The receiver feeds information to an electrode array inserted into the fluid-filled cochlea, where it provides direct electrical stimulation to the auditory nerve. Despite its great success, there is still room for improvement, so as to provide the patient with better frequency resolution, pitch information for music and speech perception and overall improved quality of sound. A better stimulation mode for the auditory nerves by increasing the number of stimulation points is believed to be a part of the solution. Current technology depends on strong electrical pulses to overcome the anatomical gap between neurons and the CI. The spreading of currents limits the number of stimulation points due to signal overlap and crosstalk.Closing the anatomical gap between spiral ganglion neurons and the CI could lower the stimulation thresholds, reduce current spread, and generate a more discrete stimulation of individual neurons. This strategy may depend on the regenerative capacity of auditory neurons, and the ability to attract and guide them to the electrode and bridge the gap.Here, we investigated the potential of cultured human and murine neurons from primary inner ear tissue and human neural progenitor cells to traverse this gap through an extracellular matrix gel.Furthermore, nanoparticles were used as reservoirs for neural attractants and applied to CI electrode surfaces. The nanoparticles retained growth factors, and inner ear neurons showed affinity for the reservoirs in vitro.The potential to obtain a more ordered neural growth on a patterned, electrically conducting nanocrystalline diamond surface was also examined. Successful growth of auditory neurons that attached and grew on the patterned substrate was observed.By combining the patterned diamond surfaces with nanoparticle-based reservoirs and nerve-stimulating gels, a novel, high resolution CI may be created. This strategy could potentially enable the use of hundreds of stimulation points compared to the 12 – 22 used today. This could greatly improve the hearing sensation for many CI recipients.
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| 26. |
- Edin, Fredrik, et al.
(författare)
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Stronger fronto-parietal connectivity accounts for development of working memory-related brain activity
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Cognitive functions, including working memory capacity, improve during childhood and early adulthood. Several maturational processes take place during that time, most importantly the myelination of axons, pruning of synapses and strengthening of the remaining synapses. However, it has not yet been shown how to directly relate these cellular changes to working memory development and associated changes in brain activity. Here, we bridge this gap by integrating biophysically-based computational modelling and functional MRI of the visuospatial working memory. Cellular mechanisms corresponding to different maturational processes were implemented in in silico 'child' networks, and the predicted difference in activity between 'child' and a reference 'adult' network was then compared to measured brain activity in children and adults. Network models with stronger connectivity between brain areas, but not networks with faster conduction or increased neuronal specificity, were supported by measured developmental increases in brain activity and correlations between frontal and parietal areas. The 'adult' networks with stronger fronto-parietal connections also exhibited greater stability during distraction, which was consistent with the developmental improvement in working memory performance.
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| 27. |
- Edin, Fredrik, et al.
(författare)
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Stronger synaptic connectivity as a mechanism behind development of working memory-related brain activity during childhood
- 2007
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Ingår i: Journal of cognitive neuroscience. - : MIT Press - Journals. - 0898-929X .- 1530-8898. ; 19:5, s. 750-760
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Tidskriftsartikel (refereegranskat)abstract
- The cellular maturational processes behind cognitive development during childhood, including the development of working memory capacity, are still unknown. By using the most standard computational model of visuospatial working memory, we investigated the consequences of cellular maturational processes, including myelination, synaptic strengthening, and synaptic pruning, on working memory-related brain activity and performance. We implemented five structural developmental changes occurring as a result of the cellular maturational processes in the biophysically based computational network model. The developmental changes in memory activity predicted from the simulations of the model were then compared to brain activity measured with functional magnetic resonance imaging in children and adults. We found that networks with stronger fronto-parietal synaptic connectivity between cells coding for similar stimuli, but not those with faster conduction, stronger connectivity within a region, or increased coding specificity, predict measured developmental increases in both working memory-related brain activity and in correlations of activity between regions. Stronger fronto-parietal synaptic connectivity between cells coding for similar stimuli was thus the only developmental process that accounted for the observed changes in brain activity associated with development of working memory during childhood.
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| 28. |
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| 29. |
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| 30. |
- Garoff, Maria, 1979-, et al.
(författare)
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Bilateral vessel-outlining carotid artery calcifications in panoramic radiographs : an independent risk marker for vascular events
- 2019
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Ingår i: BMC Cardiovascular Disorders. - : BioMed Central. - 1471-2261 .- 1471-2261. ; 19:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: In odontology, panoramic radiographs (PRs) are regularly performed. PRs depict the teeth and jaws as well as carotid artery calcifications (CACs). Patients with CACs on PRs have an increased risk of vascular events compared to healthy controls without CACs, but this association is often caused by more vascular events and risk factors at baseline. However, the risk of vascular events has only been analyzed based on the presence of CACs, and not their shape. Thus, this study determined if the shape of CACs in PRs affects the risk of future vascular events.METHODS: The study cohort included 117 consecutive patients with CACs in PRs and 121 age-matched controls without CACs. CAC shape in PRs was dichotomized into bilateral vessel-outlining CACs and other CAC shapes. Participants were followed prospectively for an endpoint of vascular events including myocardial infarction, stroke, and vascular death.RESULTS: Patients with bilateral vessel-outlining CACs had more previous vascular events than those with other CAC shapes and the healthy controls (p < 0.001, χ2). The mean follow-up duration was 9.5 years. The endpoint was reached in 83 people. Patients with bilateral vessel-outlining CACs had a higher annual risk of vascular events (7.0%) than those with other CAC shapes (4.4%) and the controls (2.6%) (p < 0.001). In multivariate analysis, bilateral vessel-outlining CACs (hazard ratio: 2.2, 95% confidence interval: 1.1-4.5) were independent risk markers for the endpoint.CONCLUSIONS: Findings of bilateral vessel-outlining CACs in PRs are independent risk markers for future vascular events.
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| 31. |
- Hall, Ulrika Andersson, et al.
(författare)
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Metabolism and Whole-Body Fat Oxidation Following Post-Exercise Carbohydrate or Protein Intake.
- 2018
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Ingår i: International journal of sport nutrition and exercise metabolism. - : Human Kinetics. - 1543-2742 .- 1526-484X. ; 28:1, s. 37-45
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated how post-exercise intake of placebo (PLA), protein (PRO) or carbohydrate (CHO) affected fat oxidation (FO) and metabolic parameters during recovery and subsequent exercise.In a cross-over design, 12 moderately trained women (VO2max 45 ± 6 ml·min(-1)·kg(-1)) performed three days of testing. A 23 min control (CON) incremental FO bike test (30-80% VO2max) was followed by 60 min exercise at 75% VO2max. Immediately post-exercise, subjects ingested PLA, 20 g PRO or 40 g CHO followed by a second FO bike test 2h later.Maximal fat oxidation (MFO) and the intensity at which MFO occurs (Fatmax) increased at the second FO test compared to the first following all three post-exercise drinks (MFO for CON=0.28±0.08, PLA=0.57±0.13, PRO=0.52±0.08, CHO=0.44±0.12 g fat·min(-1); Fatmax for CON=41±7, PLA=54±4, PRO=55±6, CHO=50±8 %VO2max, P<0.01 for all values compared to CON). Resting FO, MFO and Fatmax were not significantly different between PLA and PRO, but lower for CHO. PRO and CHO increased insulin levels at 1h post-exercise, though both glucose and insulin were equal with PLA at 2h. Increased post-exercise ketone levels only occurred with PLA.Protein supplementation immediately post-exercise did not affect the doubling in whole body fat oxidation seen during a subsequent exercise trial 2 hours later. Neither did it affect resting fat oxidation during the post-exercise period despite increased insulin levels and attenuated ketosis. Carbohydrate intake dampened the increase in fat oxidation during the second test, though a significant increase was still observed compared to the first test.
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| 32. |
- Hall, Ulrika Andersson, et al.
(författare)
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Whole-body fat oxidation increases more by prior exercise than overnight fasting in elite endurance athletes.
- 2016
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Ingår i: Applied physiology, nutrition, and metabolism = Physiologie appliquée, nutrition et métabolisme. - : Canadian Science Publishing. - 1715-5320. ; 41:4, s. 430-7
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to compare whole-body fat oxidation kinetics after prior exercise with overnight fasting in elite endurance athletes. Thirteen highly trained athletes (9 men and 4 women; maximal oxygen uptake: 66 ± 1 mL·min(-1)·kg(-1)) performed 3 identical submaximal incremental tests on a cycle ergometer using a cross-over design. A control test (CON) was performed 3 h after a standardized breakfast, a fasting test (FAST) 12 h after a standardized evening meal, and a postexercise test (EXER) after standardized breakfast, endurance exercise, and 2 h fasting recovery. The test consisted of 3 min each at 30%, 40%, 50%, 60%, 70%, and 80% of maximal oxygen uptake and fat oxidation rates were measured through indirect calorimetry. During CON, maximal fat oxidation rate was 0.51 ± 0.04 g·min(-1) compared with 0.69 ± 0.04 g·min(-1) in FAST (P < 0.01), and 0.89 ± 0.05 g·min(-1) in EXER (P < 0.01). Across all intensities, EXER was significantly higher than FAST and FAST was higher than CON (P < 0.01). Blood insulin levels were lower and free fatty acid and cortisol levels were higher at the start of EXER compared with CON and FAST (P < 0.05). Plasma nuclear magnetic resonance-metabolomics showed similar changes in both EXER and FAST, including increased levels of fatty acids and succinate. In conclusion, prior exercise significantly increases whole-body fat oxidation during submaximal exercise compared with overnight fasting. Already high rates of maximal fat oxidation in elite endurance athletes were increased by approximately 75% after prior exercise and fasting recovery.
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| 33. |
- Hayashi, Hisamitsu, et al.
(författare)
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The effect of pulsed electric fields on the electrotactic migration of human neural progenitor cells through the involvement of intracellular calcium signaling
- 2016
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Ingår i: Brain Research. - : Elsevier BV. - 0006-8993 .- 1872-6240. ; 1652, s. 195-203
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Tidskriftsartikel (refereegranskat)abstract
- Endogenous electric fields (EFs) are required for the physiological control of the central nervous system development. Application of the direct current EFs to neural stem cells has been studied for the possibility of stem cell transplantation as one of the therapies for brain injury. EFs generated within the nervous system are often associated with action potentials and synaptic activity, apparently resulting in a pulsed current in nature. The aim of this study is to investigate the effect of pulsed EF, which can reduce the cytotoxicity, on the migration of human neural progenitor cells (hNPCs). We applied the mono-directional pulsed EF with a strength of 250mV/mm to hNPCs for 6h. The migration distance of the hNPCs exposed to pulsed EF was significantly greater compared with the control not exposed to the EF. Pulsed EFs, however, had less of an effect on the migration of the differentiated hNPCs. There was no significant change in the survival of hNPCs after exposure to the pulsed EF. To investigate the role of Ca(2+) signaling in electrotactic migration of hNPCs, pharmacological inhibition of Ca(2+) channels in the EF-exposed cells revealed that the electrotactic migration of hNPCs exposed to Ca(2+) channel blockers was significantly lower compared to the control group. The findings suggest that the pulsed EF induced migration of hNPCs is partly influenced by intracellular Ca(2+) signaling.
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| 34. |
- Li, Hao, et al.
(författare)
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Guided Growth of Auditory Neurons : Bioactive Particles Towards Gapless Neural - Electrode Interface
- 2017
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Ingår i: Biomaterials. - : Elsevier BV. - 0142-9612 .- 1878-5905. ; 122, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Cochlear implant (CI) is a successful device to restore hearing. Despite continuous development, frequency discrimination is poor in CI users due to an anatomical gap between the auditory neurons and CI electrode causing current spread and unspecific neural stimulation. One strategy to close this anatomical gap is guiding the growth of neuron dendrites closer to CI electrodes through targeted slow release of neurotrophins. Biodegradable calcium phosphate hollow nanospheres (CPHSs) were produced and their capacity for uptake and release of neurotrophins investigated using I-125-conjugated glia cell line-derived neurotrophic factor (GDNF). The CPHSs were coated onto CI electrodes and loaded with neurotrophins. Axon guidance effect of slow-released neurotrophins from the CPHSs was studied in an in vitro 3D culture model. CPHS coating bound and released GDNF with an association rate constant 6.3 x 10(3) M(-1)s(-1) and dissociation rate 2.6 x 10(-5) s(-1), respectively. Neurites from human vestibulocochlear ganglion explants found and established physical contact with the GDNF-loaded CPHS coating on the CI electrodes placed 0.7 mm away. Our results suggest that neurotrophin delivery through CPHS coating is a plausible way to close the anatomical gap between auditory neurons and electrodes. By overcoming this gap, selective neural activation and the fine hearing for CI users become possible.
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| 35. |
- Liu, Wei, et al.
(författare)
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Distribution of pejvakin in human spiral ganglion : an immunohistochemical study
- 2013
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Ingår i: Cochlear Implants International. - 1467-0100 .- 1754-7628. ; 14:4, s. 225-231
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Tidskriftsartikel (refereegranskat)abstract
- Up to 10% of permanent hearing impairments in children originate from lesions in the neuronal auditory pathway. This form of auditory neuron injury called auditory neuropathy features a preservation of outer hair cell integrity but an impaired inner hair cell function and/or neuronal transmission. DFNB59 gene encodes the protein pejvakin (PJVK) and its mutations cause autosomal recessive auditory neuropathy as well as other forms of sensorineural hearing loss. The finding of distinct forms of hearing anomalies was based on studies of consanguineous families from different ethnic groups as well as studies in mice with PJVK gene mutations. In the present immunohistochemical study, the distribution of pejvakin protein in surgically obtained human cochleae was for the first time investigated. The human cochleae had normal hearing thresholds before the operation. The expression of pejvakin was located in the cell bodies of all spiral ganglion neurons rather than the nerve fibers that were labeled with Tuj 1 antibody. As Tuj 1 antibody stained the cytoplasm of Type 1 cells, pejvakin antibody labeled both type 1 and type 2 cells. The nuclei of the neurons were also PJVK-positive. No labeling was seen in the structures within the organ of Corti and the stria vascularis. In the previous study, PJVK had been detected in the hair cells, the spiral ganglion, the cochlear nuclei, the superior olivary nucleus, and the inferior colliculus in mouse. Our study demonstrated for the first time the expression of PJVK in human spiral ganglion neurons. Its functional role in neural signal propagation and synchrony needs further elucidation.
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| 36. |
- Liu, Wei, et al.
(författare)
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Molecular composition and distribution of gap junctions in the sensory epithelium of the human cochlea a super-resolution structured illumination microscopy (SR-SIM) study
- 2017
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Ingår i: Upsala Journal of Medical Sciences. - : Uppsala Medical Society. - 0300-9734 .- 2000-1967. ; 122:3, s. 160-170
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Tidskriftsartikel (refereegranskat)abstract
- Background: Mutations in the GJB2 gene, which encodes the Connexin26 (Cx26) protein, are the most common cause of childhood hearing loss in American and European populations. The cochlea contains a gap junction (GJ) network in the sensory epithelium and two connective tissue networks in the lateral wall and spiral limbus. The syncytia contain the GJ proteins beta 2 (GJB2/Cx26) and beta 6 (GJB6/Cx30). Our knowledge of their expression in humans is insufficient due to the limited availability of tissue. Here, we sought to establish the molecular arrangement of GJs in the epithelial network of the human cochlea using surgically obtained samples. Methods: We analyzed Cx26 and Cx30 expression in GJ networks in well-preserved adult human auditory sensory epithelium using confocal, electron, and super -resolution structured illumination microscopy (SR-SIM). Results: Cx30 plaques (<5 mu m) dominated, while Cx26 plaques were subtle and appeared as 'mini junctions' (2-300 nm). 3-D volume rendering of Z-stacks and orthogonal projections from single optical sections suggested that the GJs are homomeric/homotypic and consist of assemblies of identical GJs composed of either Cx26 or Cx30. Occasionally, the two protein types were co-expressed, suggesting functional cooperation. Conclusions: Establishing the molecular composition and distribution of the GJ networks in the human cochlea may increase our understanding of the pathophysiology of Cx-related hearing loss. This information may also assist in developing future strategies to treat genetic hearing loss.
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| 37. |
- Liu, Wei, et al.
(författare)
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Super-resolution structured illumination fluorescence microscopy of the lateral wall of the cochlea : the Connexin26/30 proteins are separately expressed in man
- 2016
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Ingår i: Cell and Tissue Research. - : Springer. - 0302-766X .- 1432-0878. ; , s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- Globally 360 million people have disabling hearing loss and, of these, 32 million are children. Human hearing relies on 15,000 hair cells that transduce mechanical vibrations to electrical signals in the auditory nerve. The process is powered by the endo-cochlear potential, which is produced by a vascularized epithelium that actively transports ions in conjunction with a gap junction (GJ) system. This “battery” is located “off-site” in the lateral wall of the cochlea. The GJ syncytium contains the GJ protein genes beta 2 (GJB2/connexin26 (Cx26)) and 6 (GJB6/connexin30 (Cx30)), which are commonly involved in hereditary deafness. Because the molecular arrangement of these proteins is obscure, we analyze GJ protein expression (Cx26/30) in human cochleae by using super-resolution structured illumination microscopy. At this resolution, the Cx26 and Cx30 proteins were visible as separate plaques, rather than being co-localized in heterotypic channels, as previously suggested. The Cx26 and Cx30 proteins thus seem not to be co-expressed but to form closely associated assemblies of GJ plaques. These results could assist in the development of strategies to treat genetic hearing loss in the future.
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| 38. |
- Liu, Wei, et al.
(författare)
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The Pre- and Post-Somatic Segments of the Human Type I Spiral Ganglion Neurons - Structural and Functional Considerations Related to Cochlear Implantation
- 2015
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Ingår i: Neuroscience. - : Elsevier BV. - 0306-4522 .- 1873-7544. ; 284, s. 470-482
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Tidskriftsartikel (refereegranskat)abstract
- Human auditory nerve afferents consist of two separate systems; one is represented by the large type I cells innervating the inner hair cells and the other one by the small type II cells innervating the outer hair cells. Type I spiral ganglion neurons (SGNs) constitute 96% of the afferent nerve population and, in contrast to other mammals, their soma and pre- and post-somatic segments are unmyelinated. Type II nerve soma and fibers are unmyelinated. Histopathology and clinical experience imply that human SGNs can persist electrically excitable without dendrites, thus lacking connection to the organ of Corti. The biological background to this phenomenon remains elusive. We analyzed the pre- and post-somatic segments of the type I human SGNs using immunohistochemistry and transmission electron microscopy (TEM) in normal and pathological conditions. These segments were found surrounded by non-myelinated Schwann cells (NMSCs) showing strong intracellular expression of laminin-beta 2/collagen IV. These cells also bordered the perikaryal entry zone and disclosed surface rugosities outlined by a folded basement membrane (BM) expressing laminin-beta 2 and collagen IV. It is presumed that human large SGNs are demarcated by three cell categories: (a) myelinated Schwann cells, (b) NMSCs and (c) satellite glial cells (SGCs). Their BMs express laminin-beta 2/collagen IV and reaches the BM of the sensory epithelium at the habenula perforata. We speculate that the NMSCs protect SGNs from further degeneration following dendrite loss. It may give further explanation why SGNs can persist as electrically excitable monopolar cells even after long-time deafness, a blessing for the deaf treated with cochlear implantation. (C) 2014 The Authors. Published by Elsevier Ltd. on behalf of IBRO. This is an open access article under the CC BY-NC-ND license.
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| 39. |
- Lundby, Carsten, et al.
(författare)
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Physiological, biochemical, anthropometric, and biomechanical influences on exercise economy in humans
- 2017
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Ingår i: Scandinavian Journal of Medicine & Science in Sports. - : Wiley. - 0905-7188. ; 27:12, s. 1627-1637
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Tidskriftsartikel (refereegranskat)abstract
- Interindividual variation in running and cycling exercise economy (EE) remains unexplained although studied for more than a century. This study is the first to comprehensively evaluate the importance of biochemical, structural, physiological, anthropometric, and biomechanical influences on running and cycling EE within a single study. In 22 healthy males (VO(2)max range 45.5-72.1mLmin-1kg-1), no factor related to skeletal muscle structure (% slow-twitch fiber content, number of capillaries per fiber), mitochondrial properties (volume density, oxidative capacity, or mitochondrial efficiency), or protein content (UCP3 and MFN2 expression) explained variation in cycling and running EE among subjects. In contrast, biomechanical variables related to vertical displacement correlated well with running EE, but were not significant when taking body weight into account. Thus, running EE and body weight were correlated (R-2=.94; P<.001), but was lower for cycling EE (R-2=.23; P<.023). To separate biomechanical determinants of running EE, we contrasted individual running and cycling EE considering that during cycle ergometer exercise, the biomechanical influence on EE would be small because of the fixed movement pattern. Differences in cycling and running exercise protocols, for example, related to biomechanics, play however only a secondary role in determining EE. There was no evidence for an impact of structural or functional skeletal muscle variables on EE. Body weight was the main determinant of EE explaining 94% of variance in running EE, although more than 50% of the variability of cycling EE remains unexplained.
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| 40. |
- Mattsson, C. Mikael, et al.
(författare)
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Regular moist snuff dipping does not affect endurance exercise performance
- 2013
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Konferensbidrag (refereegranskat)abstract
- Physiological and medical effects of snuff have previously been obtained either in cross-sectional studies or after snuff administration to non-tobacco users, but the effects of snuff cessation (SC) after several years of daily use on individual level are unknown. 24 participants with >2 years of daily snuff-use were tested before and after >6 weeks SC (SCG), together with a control group (CO) of 11 snuff users who kept their normal habits. Resting heart rate (HR) was significantly lower in SCG after SC. Body mass in SCG group increased by 1.4 ± 1.7 kg and blood pressure (BP) were reduced, but without significant differences between groups. Total cholesterol increased from 4.12 ± 0.54 (95% CI 3.89–4.35) to 4.46 ± 0.70 (95% CI 4.16–4.75) mM/L in SCG, due to increased LDL, and this change was significantly different from CO. Resting values of HDL, C-reactive protein, and free fatty acids (FFA) remained unchanged in both groups. During a four-stage incremental (from 50 to 80% of VO2max) and a prolonged (60 min at 50% of VO2max) cycling test HR and BP were reduced in SCG, while oxygen uptake (VO2), respiratory exchange ratio, blood lactate (bLa) and blood glucose (bGlu) concentration, and rate of perceived exertion were unchanged. All measurements were unchanged in CO. During the prolonged exercise FFA was reduced but there was no significant difference between groups. During the maximal treadmill running test peak values of VO2, pulmonary ventilation (VE), time to exhaustion and bLa were unchanged in both groups. In conclusion, endurance exercise performance (VO2max and maximal endurance time) does not seem to be affected by prolonged snuff use, while effects on cardiovascular risk factors are contradictory.
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| 41. |
- Montero, D., et al.
(författare)
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Sexual dimorphism of substrate utilization: Differences in skeletal muscle mitochondrial volume density and function
- 2018
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Ingår i: Experimental Physiology. - : Wiley. - 0958-0670. ; 103:6, s. 851-859
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Tidskriftsartikel (refereegranskat)abstract
- Fat oxidation during exercise is greater in females than in males. We sought to determine whether sex differences in substrate metabolism are paralleled by distinct skeletal muscle mitochondrial volume density and oxidative capacity. Whole-body substrate (fat and carbohydrate) utilization during submaximal treadmill running was assessed, and skeletal muscle biopsies were taken to determine mitochondrial volume density and function in healthy young females (n=12) and males (n=12) matched by aerobic exercise capacity and exercise performance. Females presented a lower respiratory exchange ratio (0.87 +/- 0.04 versus 0.91 +/- 0.04, P=0.023) and whole-body carbohydrate oxidation (27.8 +/- 8.3 versus 35.8 +/- 6.5mgkg(-1)min(-1), P=0.027), whereas fat oxidation was higher (8.7 +/- 2.8 versus 5.9 +/- 2.6mgkg(-1)min(-1), P=0.034) during submaximal exercise compared with males. In skeletal muscle biopsies, females demonstrated augmented mitochondrial volume density (7.51 +/- 1.77 versus 5.90 +/- 1.72%, P=0.035) and oxidative capacity for fatty acid [36.6 +/- 12.8 versus 24.5 +/- 7.3pmol O(2)s(-1)(mg wet weight)(-1), P=0.009] and lactate [71.1 +/- 24.4 versus 53.2 +/- 14.6pmol O(2)s(-1)(mg wet weight)(-1), P=0.040]. No sex differences in respiratory exchange ratio, whole-body fat oxidation and skeletal muscle variables were detected when adjusted for anthropometric variables including body mass or leg mass, which were lower in females. In conclusion, female prioritization of fat over carbohydrate oxidation during exercise is underpinned by augmented body size-related mitochondrial volume density, fatty acid and lactate oxidative capacity in skeletal muscle fibres.
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| 42. |
- Natan, Michal, et al.
(författare)
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Two are Better than One : Combining ZnO and MgF2 Nanoparticles Reduces Streptococcus pneumoniae and Staphylococcus aureus Biofilm Formation on Cochlear Implants
- 2016
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Ingår i: Advanced Functional Materials. - : Wiley. - 1616-301X .- 1616-3028. ; 26:15, s. 2473-2481
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Tidskriftsartikel (refereegranskat)abstract
- Streptococcus pneumoniae (S. pneumoniae) and Staphylococcus aureus (S.aureus) are considered the most common colonizers of cochlear implants (CI), which have prompted the search for new ways to inhibit their growth and biofilm development. In the current study, CI-based platforms are prepared and sonochemically coated with ZnO or MgF2 nanoparticles (NPs), two agents previously shown to possess antibacterial properties. Additionally, a method is developed for coating both ZnO and MgF2 on the same platform to achieve synergistic activity against both pathogens. Each surface is characterized, and the optimal conditions for the NP homogenous distribution on the surface are determined. The ZnO-MgF2 surface significantly reduces the S. pneumoniae and S. aureus biofilm compared with the surfaces coated with either ZnO or MgF2, even though it contains smaller amounts of each NP type. Importantly, leaching assays show that the NPs remain anchored to the surface for at least 7 d. Finally, biocompatibility studies demonstrate that coating with low concentrations of ZnO-MgF2 results in no toxicity toward primary human fibroblasts from the auditory canal. Taken together, these findings underscore the potential of using NP combinations such as the one presented here to efficiently inhibit bacterial colonization and growth on medical devices such as CIs.
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| 43. |
- Nordling, Sofia, et al.
(författare)
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Vascular repair utilising immobilised heparin conjugate for protection against early activation of inflammation and coagulation
- 2015
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Ingår i: Thrombosis and Haemostasis. - 0340-6245 .- 2567-689X. ; 113:6, s. 1312-1322
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Tidskriftsartikel (refereegranskat)abstract
- Ischaemia-reperfusion injury (IRI) poses a major challenge in many thrombotic conditions and in whole organ transplantation. Activation of the endothelial cells and shedding of the protective vascular glycocalyx during IRI increase the risk of innate immune activation, cell infiltration and severe thrombus formation, promoting damage to the tissue. Here, we present a novel one-step strategy to protect the vas, culature by immobilisation of a unique multi-arm heparin conjugate to the endothelium. Applying a new in vitro blood endothelial cell chamber model, the heparin conjugate was found to bind not only to primary human endothelial cells but also directly to the collagen to which the cells adhered. Incubation of hypoxic endothelial cells with freshly drawn human blood in the blood chambers elicited coagulation activation reflected by thrombin anti-thrombin formation and binding of platelets and neutrophils. Immobilisation of the heparin conjugate to the hypoxic endothelial cells created a protective coating, leading to a Significant reduction of the recruitment of blood cells and coagulation activation compared to untreated hypoxic endothelial cells. This novel approach of immobilising multi-arm heparin conjugates on the endothelial cells and collagen of the basement membrane ensures to protect the endothelium against IRI in thrombotic disorders and in transplantation.
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| 44. |
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| 45. |
- Pettersson, Stefan, 1972, et al.
(författare)
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A Hydrogel Drink With High Fructose Content Generates Higher Exogenous Carbohydrate Oxidation and Lower Dental Biofilm pH Compared to Two Other, Commercially Available, Carbohydrate Sports Drinks
- 2020
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Ingår i: Frontiers in Nutrition. - : Frontiers Media SA. - 2296-861X. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to evaluate the substrate oxidation of three commercially available, 14%-carbohydrate sports drinks with different compositions, osmolality, and pH for their impact on dental exposure to low pH. In a cross-over, randomized double-blinded design, 12 endurance athletes (age 31. 2 +/- 7.7 years, (V) over dotO(2max) 65.6 +/- 5.0 mL.kg(-1)) completed 180 min of cycling at 55% W-max. During the first 100 min of cycling, athletes consumed amylopectin starch (AP), maltodextrin+sucrose (MD+SUC), or maltodextrin+fructose hydrogel (MD+FRU) drinks providing 95 g carbohydrate.h(-1), followed by water intake only at 120 and 160 min. Fuel use was determined using indirect calorimetry and stable-isotope techniques. Additionally, dental biofilm pH was measured using the microtouch method in a subsample of participants (n= 6) during resting conditions before, and at different time intervals up to 45 min following a single bolus of drink. Exogenous carbohydrate oxidation (CHOEXO) during the 2nd hour of exercise was significantly (P< 0.05) different between all three drinks: MD+FRU (1.17 +/- 0.17 g.min(-1)), MD+SUC (1.01 +/- 0.13 g.min(-1)), and AP (0.84 +/- 0.11 g.min(-1)). At the end of exercise, CHO(EXO)and blood glucose concentrations (3.54 +/- 0.50, 4.07 +/- 0.67, and 4.28 +/- 0.47 mmol.L-1, respectively) were significantly lower post MD+FRU consumption than post MD+SUC and AP consumption (P< 0.05). Biofilm acidogenicity at rest demonstrated a less pronounced pH fall for MD+FRU compared to the acidulant-containing MD+SUC and AP (P< 0.05). In conclusion, while total intake of MD+FRU showed signs of completed uptake before end of monitoring, this was less so for MD+SUC, and not at all the case for AP. Thus, this study showed that despite carbohydrates being encapsulated in a hydrogel, a higher CHO(EXO)was observed following MD+FRU drink ingestion compared to AP and MD+SUC consumption upon exposure to the acidic environment of the stomach. This finding may be related to the higher fructose content of the MD+FRU drink compared with the MD+SUC and AP drinks. Furthermore, a carbohydrate solution without added acidulants, which are commonly included in commercial sport drinks, may have less deleterious effects on oral health.
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| 46. |
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| 47. |
- Pettersson, Stefan, 1972, et al.
(författare)
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Effects of supplementing with an 18% carbohydrate-hydrogel drink versus a placebo during whole-body exercise in -5 °C with elite cross-country ski athletes: a crossover study
- 2019
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Ingår i: Journal of the International Society of Sports Nutrition. - : Informa UK Limited. - 1550-2783. ; 16:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND:Whilst the ergogenic effects of carbohydrate intake during prolonged exercise are well-documented, few investigations have studied the effects of carbohydrate ingestion during cross-country skiing, a mode of exercise that presents unique metabolic demands on athletes due to the combined use of large upper- and lower-body muscle masses. Moreover, no previous studies have investigated exogenous carbohydrate oxidation rates during cross-country skiing. The current study investigated the effects of a 13C-enriched 18% multiple-transportable carbohydrate solution (1:0.8 maltodextrin:fructose) with additional gelling polysaccharides (CHO-HG) on substrate utilization and gastrointestinal symptoms during prolonged cross-country skiing exercise in the cold, and subsequent double-poling time-trial performance in ~ 20 °C.METHODS:Twelve elite cross-country ski athletes (6 females, 6 males) performed 120-min of submaximal roller-skiing (69.3 ± 2.9% of [Formula: see text]O2peak) in -5 °C while receiving either 2.2 g CHO-HG·min- 1 or a non-caloric placebo administered in a double-blind, randomized manner. Whole-body substrate utilization and exogenous carbohydrate oxidation was calculated for the last 60 min of the submaximal exercise. The maximal time-trial (2000 m for females, 2400 m for males) immediately followed the 120-min submaximal bout. Repeated-measures ANOVAs with univariate follow-ups were conducted, as well as independent and paired t-tests, and significance was set at P < 0.05. Data are presented as mean ± SD.RESULTS:Exogenous carbohydrate oxidation contributed 27.6 ± 6.6% to the total energy yield with CHO-HG and the peak exogenous carbohydrate oxidation rate reached 1.33 ± 0.27 g·min- 1. Compared to placebo, fat oxidation decreased by 9.5 ± 4.8% with CHO-HG, total carbohydrate oxidation increased by 9.5 ± 4.8% and endogenous carbohydrate utilization decreased by 18.1 ± 6.4% (all P < 0.05). No severe gastrointestinal symptoms were reported in either trial and euhydration was maintained in both trials. Time-trial performance (8.4 ± 0.4 min) was not improved following CHO-HG compared to placebo (- 0.8 ± 3.5 s; 95% confidence interval - 3.0 to 1.5 s; P = 0.46). No sex differences were identified in substrate utilization or relative performance.CONCLUSIONS:Ingestion of an 18% multiple-transportable carbohydrate solution with gelling polysaccharides was found to be well-tolerated during 120 min of submaximal whole-body exercise, but did not improve subsequent maximal double-poling performance.
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| 48. |
- Pettersson, Stefan, 1972, et al.
(författare)
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Six Weeks of Aerobic Exercise in Untrained Men With Overweight/Obesity Improved Training Adaptations, Performance and Body Composition Independent of Oat/Potato or Milk Based Protein-Carbohydrate Drink Supplementation.
- 2021
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Ingår i: Frontiers in Nutrition. - : Frontiers Media S.A.. - 2296-861X. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Background: Protein availability around aerobic exercise might benefit aerobic capacity and body composition in normal weight adults. However, it is unknown if individuals with overweight/obesity elicit similar adaptations or improve other cardiometabolic/health-related markers in response to different types of protein. Thus, our aim was to study the effect of supplementation of two different protein drinks in conjunction with exercise on aerobic capacity, body composition and blood health markers in untrained subjects with overweight or obesity. Methods: The present study measured training adaptation and health parameters over a 6 week period in untrained men with overweight/obesity (n = 28; BMI 30.4 ± 2.2 kg/m2) ingesting either plant- (Oat/Potato; n = 8) or animal-based (Milk; n = 10) protein-carbohydrate drinks (10 g of protein/serving), or a control carbohydrate drink (n = 10) acutely before and after each training session (average three sessions/week @ 70% HRmax). Pre-post intervention ˙VO2peakV˙O2peak , muscle biopsies and blood samples were collected, body composition measured (DXA) and two different exercise tests performed. Body weight was controlled with participants remaining weight stable throughout the intervention. Results: For the groups combined, the training intervention significantly increased ˙VO2peakV˙O2peak (8%; P < 0.001), performance in a time-to-exhaustion trial (~ 100%; P < 0.001), mitochondrial protein content and enzyme activity (~20-200%). Lean body mass increased (1%; P < 0.01) and fat mass decreased (3%; P < 0.01). No significant effects on fasting blood glucose, insulin, lipids or markers of immune function were observed. There were no significant interactions between drink conditions for training adaptation or blood measurements. For body composition, the Oat/Potato and carbohydrate group decreased leg fat mass significantly more than the Milk group (interaction P < 0.05). Conclusions: Aerobic capacity and body composition were improved and a number of mitochondrial, glycolytic and oxidative skeletal muscle proteins and enzyme activities were upregulated by a 6 week training intervention. However, none of the parameters for endurance training adaptation were influenced by protein supplementation before and after each training session.
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| 49. |
- Renberg, Fredrik Edin, et al.
(författare)
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Microdecisions instead of coercion : patient participation and self-perceived discrimination in a psychiatric ward
- 2019
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Ingår i: Nordic Journal of Psychiatry. - : Taylor & Francis. - 0803-9488 .- 1502-4725. ; 73:8, s. 532-538
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Tidskriftsartikel (refereegranskat)abstract
- Aims: Patients may experience unfair reception when in contact with psychiatric services. The aims are to illuminate these perceptions, and the extent of inpatients' involvement in their care, and if degree of involvement depends on compulsory or voluntary care. Furthermore, we sought to determine if an educational intervention for staff members, including systematic listening and offering the inpatients involvement using microdecisions, affects the inpatients' experiences and the use of coercion.Materials and methods: We used a naturalistic setting case control design in two psychiatric wards for one year, including all inpatients (n = 685) of which 458 took part of the microdecision intervention. Structured direct interviews were carried out with inpatients based on the Discrimination and Stigma Scale (DISC), Dyadic OPTION, and CollaboRATE instruments before (n = 19) and after (n = 46) the intervention. Frequencies of coercive measures before and after the intervention were compared (n = 685).Results: Respondents subjected to the intervention experienced less discrimination related to psychiatric care compared to responders not subjected. Tendencies of improvements post intervention were found for some aspects of involvement, as attention to concerns and possibilities to ask questions. A decrease in the use of coercive measures at three and six months after the start of the intervention was observed.Conclusion: Results suggest that the intervention could decrease the inpatients' experiences of discrimination during psychiatric care as well as the use of coercion in the service. The Dyadic OPTION instrument showed a mixed picture with results implying improvements in some areas and impairments in others.
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| 50. |
- Rosdahl, Hans, et al.
(författare)
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The Moxus Modular metabolic sustem evaluated with two sensors for ventilation against the Douglas bag method
- 2013
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Ingår i: European Journal of Applied Physiology. - : Springer Science and Business Media LLC. - 1439-6319 .- 1439-6327. ; 113:5, s. 1353-1367
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Tidskriftsartikel (refereegranskat)abstract
- This study evaluated the Moxus metabolic system with the Douglas bag method (DBM) as criterion. Reliability and validity were investigated in a wide range of ventilation and oxygen uptake and two sensors for determining ventilation were included. Thirteen well-trained athletes participated in one pre-test and four tests for data collection, exercising on a cycle ergometer at five submaximal powers (50-263 W) and at [Formula: see text]. Gas exchange variables were measured simultaneously using a serial setup with data collected on different days in an order randomized between Moxus with pneumotachometer (MP) and turbine flowmeter (MT) sensors for ventilation. Reliability with both sensors was comparable to the DBM. Average CV (%) of all exercise intensities were with MP: 3.0 ± 1.3 for VO(2), 3.8 ± 1.5 for VCO(2), 3.1 ± 1.2 for the respiratory exchange ratio (RER) and 4.2 ± 0.8 for V (E). The corresponding values with MT were: 2.7 ± 0.3 for VO(2), 4.7 ± 0.4 for VCO(2), 3.3 ± 0.9 for RER and 4.8 ± 1.4 for V (E). Validity was acceptable except for small differences related to the determination of ventilation. The relative differences in relation to DBM at the powers including [Formula: see text] were similar for both sensors with the ranges being: +4 to -2 % for V (E), +5 to -3 % for VO(2) and +5 to -4 % for VCO(2) while RER did not differ at any power. The Moxus metabolic system shows high and adequate reliability and reasonable validity over a wide measurement range. At a few exercise levels, V (E) differed slightly from DBM, resulting in concomitant changes in VO(2) and VCO(2).
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