kth.sePublications
Change search
Refine search result
3456 251 - 265 of 265
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 251.
    Vizcaíno-Vergara, Maria Del Mar
    et al.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Fluid Mechanics and Engineering Acoustics, Marcus Wallenberg Laboratory MWL. School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London, E1 4NS, United Kingdom.
    Tunnicliffe, L. B.
    Birla Carbon, Marietta, GA 30062 USA..
    Busfield, J. J. C.
    Queen Mary Univ London, Sch Engn & Mat Sci, Mile End Rd, London E1 4NS, England..
    Kari, Leif
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Fluid Mechanics and Engineering Acoustics, Marcus Wallenberg Laboratory MWL.
    Viscoelastic characterisation of carbon black reinforced rubber using the torsion pendulum: Guidelines and temperature sweep results2022In: Polymer testing, ISSN 0142-9418, E-ISSN 1873-2348, Vol. 114, article id 107692Article in journal (Refereed)
    Abstract [en]

    A comprehensive set of guidelines on the use of the torsion pendulum for the viscoelastic characterisation of carbon black reinforced rubber is presented, including the set up selection, the post processing steps and the final evaluation of the method using temperature sweep results at small strains. The torsion pendulum is based on the free vibration principle, in which the sample is instantaneously perturbed to initiate a torsional movement and then left to freely vibrate. From the frequency and damping of this impulse response function, the properties of the material can be obtained against temperature and time. However, despite the extensive use for many years of the torsion pendulum, the difficulty of activating only the desired torsional mode hinders the acquisition of accurate results. The method presented aims to improve the torsion pendulum performance and can be divided in two stages. The pre-testing phase covers the influence of the test set up and sample geometry on the measured response. The test set up will determine the frequency at which the dynamic properties are obtained, while the sample geometry will influence the torsional strain and bending deflection. The post-testing phase includes the steps to post-process the curve and the criteria to identify and select the most reliable data sets from all of the measured data. The quality of the curve is assessed in the frequency domain by evaluating the frequency components of its Fast Fourier Transform and in the time domain by evaluating its fit to an ideal exponentially decreasing sinusoidal curve. The final selection of the response functions that can be used to measure the viscoelastic properties of the rubber samples is made based on the maximum strain level and the minimum variation of the dynamic properties within one curve. The validity of the method is then tested by comparing temperature sweep results before and after the application of the presented guidelines, where a clear decrease on the results deviation can be observed. Finally, the results obtained with this method are compared to Dynamic Mechanical Analysis results over the same temperature range, where a good fit is obtained. Thus, this investigation presents a comprehensive method, useful to all torsional pendulum users aiming to measure and characterise the mechanical behaviour of viscoelastic materials.

  • 252.
    Wang, Ruoli
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, BioMEx. KTH, School of Engineering Sciences (SCI), Mechanics. Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.
    Gäverth, J.
    Herman, Pawel
    KTH, School of Electrical Engineering and Computer Science (EECS), Computer Science, Computational Science and Technology (CST).
    Changes in the neural and non-neural related properties of the spastic wrist flexors after treatment with botulinum toxin a in post-stroke subjects: An optimization study2018In: Frontiers in Bioengineering and Biotechnology, E-ISSN 2296-4185, Vol. 9, no June, article id 73Article in journal (Refereed)
    Abstract [en]

    Quantifying neural and non-neural contributions to the joint resistance in spasticity is essential for a better evaluation of different intervention strategies such as botulinum toxin A (BoTN-A). However, direct measurement of muscle mechanical properties and spasticity-related parameters in humans is extremely challenging. The aim of this study was to use a previously developed musculoskeletal model and optimization scheme to evaluate the changes of neural and non-neural related properties of the spastic wrist flexors during passive wrist extension after BoTN-A injection. Data of joint angle and resistant torque were collected from 21 chronic stroke patients before, and 4 and 12 weeks post BoTN-A injection using NeuroFlexor, which is a motorized force measurement device to passively stretch wrist flexors. The model was optimized by tuning the passive and stretch-related parameters to fit the measured torque in each participant. It was found that stroke survivors exhibited decreased neural components at 4 weeks post BoNT-A injection, which returned to baseline levels after 12 weeks. The decreased neural component was mainly due to the increased motoneuron pool threshold, which is interpreted as a net excitatory and inhibitory inputs to the motoneuron pool. Though the linear stiffness and viscosity properties of wrist flexors were similar before and after treatment, increased exponential stiffness was observed over time which may indicate a decreased range of motion of the wrist joint. Using a combination of modeling and experimental measurement, valuable insights into the treatment responses, i.e., transmission of motoneurons, are provided by investigating potential parameter changes along the stretch reflex pathway in persons with chronic stroke.

  • 253.
    Wiklund, Urban
    et al.
    Department of Biomedcal Engineering and Informatics, Univeristy Hospital of Umeå.
    Karlsson, Marcus
    Department of Biomedcal Engineering and Informatics, Univeristy Hospital of Umeå.
    Ostlund, Nils
    Department of Biomedcal Engineering and Informatics, Univeristy Hospital of Umeå.
    Berglin, Lena
    School of Textiles, University of Borås.
    Lindecrantz, Kaj
    School of Engineering, University of Borås.
    Karlsson, Stefan
    Engineering and Informatics, Univeristy Hospital of Umeå.
    Sandsjö, Leif
    National Institute of Working Life, Gothenburg.
    Adaptive spatio-temporal filtering of disturbed ECGs: a multi-channel approach to heartbeat detection in smart clothing2007In: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 45, no 6, p. 515-523Article in journal (Refereed)
    Abstract [en]

    Intermittent disturbances are common in ECG signals recorded with smart clothing: this is mainly because of displacement of the electrodes over the skin. We evaluated a novel adaptive method for spatio-temporal filtering for heartbeat detection in noisy multi-channel ECGs including short signal interruptions in single channels. Using multi-channel database recordings (12-channel ECGs from 10 healthy subjects), the results showed that multi-channel spatio-temporal filtering outperformed regular independent component analysis. We also recorded seven channels of ECG using a T-shirt with textile electrodes. Ten healthy subjects performed different sequences during a 10-min recording: resting, standing, flexing breast muscles, walking and pushups. Using adaptive multi-channel filtering, the sensitivity and precision was above 97% in nine subjects. Adaptive multi-channel spatio-temporal filtering can be used to detect heartbeats in ECGs with high noise levels. One application is heartbeat detection in noisy ECG recordings obtained by integrated textile electrodes in smart clothing.

  • 254.
    Williams, Cecilia
    et al.
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology.
    Pontén, F
    Moberg, C
    Söderkvist, P
    Uhlén, M
    Pontén, J
    Sitbon, G
    Lundeberg, J
    A high frequency of sequence alterations is due to formalin fixation of archival specimens.1999In: American Journal of Pathology, ISSN 0002-9440, E-ISSN 1525-2191, Vol. 155, no 5Article in journal (Refereed)
    Abstract [en]

    Genomic analysis of archival tissues fixed in formalin is of fundamental importance in biomedical research, and numerous studies have used such material. Although the possibility of polymerase chain reaction (PCR)-introduced artifacts is known, the use of direct sequencing has been thought to overcome such problems. Here we report the results from a controlled study, performed in parallel on frozen and formalin-fixed material, where a high frequency of nonreproducible sequence alterations was detected with the use of formalin-fixed tissues. Defined numbers of well-characterized tumor cells were amplified and analyzed by direct DNA sequencing. No nonreproducible sequence alterations were found in frozen tissues. In formalin-fixed material up to one mutation artifact per 500 bases was recorded. The chance of such artificial mutations in formalin-fixed material was inversely correlated with the number of cells used in the PCR-the fewer cells, the more artifacts. A total of 28 artificial mutations were recorded, of which 27 were C-T or G-A transitions. Through confirmational sequencing of independent amplification products artifacts can be distinguished from true mutations. However, because this problem was not acknowledged earlier, the presence of artifacts may have profoundly influenced previously reported mutations in formalin-fixed material, including those inserted into mutation databases.

  • 255.
    Wåhslén, Jonas
    et al.
    KTH, School of Technology and Health (STH), Data- och elektroteknik.
    Orhan, Ibrahim
    KTH, School of Technology and Health (STH), Data- och elektroteknik.
    Lindh, Thomas
    KTH, School of Technology and Health (STH).
    Local Time Synchronization in Bluetooth Piconets for Data Fusion Using Mobile Phones2011In: BSN 2011: 8th International Conference on Body Sensor Networks, 2011, p. 113-138Conference paper (Refereed)
    Abstract [en]

    This paper presents a method to synchronize the clocks in a Bluetooth piconet from the application layer in a mobile phone. It adapts algorithms for time synchronization of distributed systems and the Internet to Bluetooth networks. The performance issues that cause problems for data synchronization between master and slaves in Bluetooth are highlighted. The tests show that the synchronization error is limited to one sampling time.

  • 256. Xing, Zhe
    et al.
    Xue, Ying
    Dånmark, Staffan
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Finne-Wistrand, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Arvidson, Kristina
    Hellem, Solve
    Yang, Zhuang-Qun
    Mustafa, Kamal
    Comparison of short-run cell seeding methods for poly(L-lactide-co-1,5-dioxepan-2-one) scaffold intended for bone tissue engineering2011In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 34, no 5, p. 432-441Article in journal (Refereed)
    Abstract [en]

    Constructs intended for bone tissue engineering are influenced by the initial cell seeding procedure. The seeding method should be rapid, convenient, improve cell spatial distribution, and have no negative effects on cellular viability and differentiation. This study aimed to compare the effect of short-run seeding methods (centrifuge and vortex) with a static method on the scaffolds prepared from poly(L-lactide-co-1,5-dioxepan-2-one) by solvent-casting particulate-leaching (SCPL) technique. Human osteoblast-like cells (HOB) were seeded by the three methods described above. The seeding efficiency was determined by attached cell numbers. Cellular proliferation was analyzed by WST-1 and dsDNA assay. Cell distribution was examined by scanning electron (SEM) and fluorescence microscopy. Expression of Alkaline Phosphatase (ALP), Collagen type I (Col I), Osteocalcin (OC) and Proliferating Cell Nuclear Antigen (PCNA) were determined by real time RT-PCR. Results indicated that centrifuge and vortex increased seeding efficiency and had no negative effects on cellular viability. The data obtained by the fluorescence microscope confirmed the SEM results that the vortex method improved cell distribution through the scaffolds more than the other two methods (p<0.05). The RT-PCR results showed no significant differences on the expression of mRNA between the three methods of the above markers. The vortex method was found to be a simple and feasible seeding method for the poly(L-lactide-co-1,5-dioxepan-2-one) scaffolds.

  • 257.
    Xu, Cheng
    KTH, School of Engineering Sciences (SCI), Physics, Physics of Medical Imaging.
    A Segmented Silicon Strip Detector for Photon-Counting Spectral Computed Tomography2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Spectral computed tomography with energy-resolving detectors has a potential to improve the detectability of images and correspondingly reduce the radiation dose to patients by extracting and properly using the energy information in the broad x-ray spectrum. A silicon photon-counting detector has been developed for spectral CT and it has successfully solved the problem of high photon flux in clinical CT applications by adopting the segmented detector structure and operating the detector in edge-on geometry. The detector was evaluated by both the simulation and measurements.

    The effects of energy loss and charge sharing on the energy response of this segmented silicon strip detector with different pixel sizes were investigated by Monte Carlo simulation and a comparison to pixelated CdTe detectors is presented. The validity of spherical approximations of initial charge cloud shape in silicon detectors was evaluated and a more accurate statistical model has been proposed.

    A photon-counting energy-resolving application specific integrated circuit (ASIC) developed for spectral CT was characterized extensively by electrical pulses, pulsed laser and real x-ray photons from both the synchrotron and an x-ray tube. It has been demonstrated that the ASIC performs as designed. A noise level of 1.09 keV RMS has been measured and a threshold dispersion of 0.89 keV RMS has been determined. The count rate performance of the ASIC in terms of count loss and energy resolution was evaluated by real x-rays and promising results have been obtained.

    The segmented silicon strip detector was evaluated using synchrotron radiation. An energy resolution of 16.1% has been determined with 22 keV photons in the lowest flux limit, which deteriorates to 21.5% at an input count rate of 100 Mcps mm−2. The fraction of charge shared events has been estimated and found to be 11.1% for 22 keV and 15.3% for 30 keV. A lower fraction of charge shared events and an improved energy resolution can be expected by applying a higher bias voltage to the detector.

    Download full text (pdf)
    PhD_thesis_ChengXu
  • 258.
    Zheng, Miaomiao
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Härmark, Johan
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Structural Biotechnology.
    Grishenkov, Dmitry
    KTH, School of Technology and Health (STH), Medical Engineering.
    Janerot Sjöberg, Birgitta
    CLINTEC, Department of Medical Imaging and Technology, Karolinska Institute.
    Polymer-Shelled Ultrasound Contrast Agents with controlled size and polydispersity.2011In: Nanomedicine: Nanotechnology, Biology & Medicine, 2011Conference paper (Refereed)
    Abstract [en]

    Ultrasound imaging techniques can be greatly improved by the use of ultrasound contrast agents (UCAs). Gas bubbles encapsulated into biocompatible polymer shell are of particular interest of this work. Shell of the bubbles produced from Poly-Vinyl-Alcohol (PVA) offers considerable chemical versatility and stability. However, questions regarding the size and polydispersity of the microbubbles must be further investigated. The ideal UCAs should not obstruct the blood flow in pulmonary capillaries which diameter is less than 10 μm. From the technical perspective UCAs should modify the acoustic properties of a region of interest, by increasing backscattered efficiency. In order to enhance the ultrasound response UCAs should be engineered with narrow size distribution. In the present work PVA-shelled UCAs with controlled size and polydispersity is manufactured under varied parameters of the manufacturing protocol. It was observed that temperature of the surrounding atmosphere has major effect on the size of the UCAs, while polydispersity is regulated by geometry and speed of the disperser. Finally, the acoustic response of these microbubbles is tested using developed ultrasound test rig. The enhancement of the backscattered power of about 25 dB from a suspension of the microbubbles is observed at 5 MHz ultrasound frequency. Keeping in mind that in clinical practice ultrasound scatter from the blood is of about 30 dB weaker than scatter from surrounding tissue, introduction of novel PVA microbubbles will potentially improve diagnosis of the cardiovascular patients.

  • 259.
    Zhou, Jing
    et al.
    University of Tampere.
    Zhang, Weikai
    University of Tampere.
    Poe, Dennis
    University of Tampere.
    Qin, Jian
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Fornara, Andrea
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Zhang, Ya
    University of Tampere.
    Ramadan, Usama
    University of Helsinki.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Pyykkö, Ilmari
    University of Tampere.
    MRI manifestation of novel superparamagnetic iron oxide nanoparticles in the rat inner ear2010In: Nanomedicine, ISSN 1743-5889, Vol. 5, no 5, p. 739-754Article in journal (Refereed)
    Abstract [en]

    Aim: Superparamagnetic iron oxide nanoparticles hierarchically coated with oleic acid and Pluronic F127 copolymers (POA@SPION) have shown exceptional 12 contrast enhancement. The aim of the present work was to investigate the MRI manifestation of POA@SPION in the inner ear. Materials & methods: A total of 26 male Wister rats were selected for testing POA@SPION administered through intracochlear, intratympanic and intravenous routes. MRI was performed with a 4.7 T MR scanner. Results & conclusion: POA@SPION can be introduced into the perilymph space, after which it becomes widely distributed and can demonstrate the integrity of the perilymph-endolymph barrier. Positive highlighting of the endolymph compartment against the darkened perilymph was visualized for the first time. POA@SPION passed through the middle-inner ear barriers in only small amounts, but stayed in the perilymph for 3 days. They did not traverse the blood-perilymph barrier or blood-endolymph barrier. The inner ear distribution of POA@SPION was confirmed by histology. POA@SPION is a promising T2 negative contrast agent.

  • 260.
    Åslund, Magnus
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederström, Björn
    KTH, School of Engineering Sciences (SCI), Physics.
    Lundqvist, Mats
    KTH, School of Engineering Sciences (SCI), Physics.
    Danielsson, Mats
    KTH, School of Engineering Sciences (SCI), Physics.
    AEC for scanning digital mammography based on variation of scan velocity2005In: Medical physics (Lancaster), ISSN 0094-2405, Vol. 32, no 11, p. 3367-3374Article in journal (Refereed)
    Abstract [en]

    A theoretical evaluation of nonuniform x-ray field distributions in mammography was conducted. An automatic exposure control (AEC) is proposed for a scanning full field digital mammography system. It uses information from the leading part of the detector to vary the scan velocity dynamically, thus creating a nonuniform x-ray field in the scan direction. Nonuniform radiation fields were also created by numerically optimizing the scan velocity profile to each breast's transmission distribution, with constraints on velocity and acceleration. The goal of the proposed AEC is to produce constant pixel signal-to-noise ratio throughout the image. The target pixel SNR for each image could be set based on the breast thickness, breast composition, and the beam quality as to achieve the same contrast-to-noise ratio between images for structures of interest. The results are quantified in terms of reduction in entrance surface air kerma (ESAK) and scan time relative to a uniform x-ray field. The theoretical evaluation was performed on a set of 266 mammograms. The performance of the different methods to create nonuniform fields decreased with increased detector width, from 18% to 11% in terms of ESAK reduction and from 30% to 25% in terms of scan time reduction for the proposed AEC and detector widths from 10 to 60 mm. Some correlation was found between compressed breast thickness and the projected breast area onto the image field. This translated into an increase of the ESAK and decrease of the scan time reduction with breast thickness. Ideally a nonuniform field in two dimensions could reduce the entrance dose by 39% on average, whereas a field nonuniform in only the scanning dimension ideally yields a 20% reduction. A benefit with the proposed AEC is that the risk of underexposing the densest region of the breast can be virtually eliminated.

  • 261.
    Åslund, Magnus
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederström, Björn
    KTH, School of Engineering Sciences (SCI), Physics.
    Lundqvist, Mats
    KTH, School of Engineering Sciences (SCI), Physics.
    Danielsson, Mats
    KTH, School of Engineering Sciences (SCI), Physics.
    Evaluation of an AEC system for scanning photon counting mammography based on variation of scan velocityIn: Medical physics (Lancaster), ISSN 0094-2405Article in journal (Other academic)
  • 262.
    Åslund, Magnus
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederström, Björn
    KTH, School of Engineering Sciences (SCI), Physics.
    Lundqvist, Mats
    KTH, School of Engineering Sciences (SCI), Physics.
    Danielsson, Mats
    KTH, School of Engineering Sciences (SCI), Physics.
    Physical characterization of a scanning photon counting digital mammography system based on Si-strip detectors2007In: Medical physics (Lancaster), ISSN 0094-2405, Vol. 34, no 6, p. 1918-1925Article in journal (Refereed)
    Abstract [en]

    The physical performance of a scanning multislit full field digital mammography system was determined using basic image quality parameters. The system employs a direct detection detector comprised of linear silicon strip sensors in an edge-on geometry connected to photon counting electronics. The pixel size is 50 mu m and the field of view 24 x 26 cm(2). The performance was quantified using the presampled modulation transfer function, the normalized noise power spectrum and the detective quantum efficiency (DQE). Compared to conventional DQE methods, the scanning geometry with its intrinsic scatter rejection poses additional requirements on the measurement setup, which are investigated in this work. The DQE of the photon counting system was found to be independent of the dose level to the detector in the 7.6-206 mu Gy range. The peak DQE was 72% and 73% in the scan and slit direction, respectively, measured with a 28 kV W-0.5 mm Al anodefilter combination with an added 2 mm Al filtration.

  • 263.
    Åslund, Magnus
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Cederström, Björn
    KTH, School of Engineering Sciences (SCI), Physics.
    Lundqvist, Mats
    KTH, School of Engineering Sciences (SCI), Physics.
    Danielsson, Mats
    KTH, School of Engineering Sciences (SCI), Physics, Physics of Medical Imaging.
    Scatter rejection in multislit digital mammography2006In: Medical physics (Lancaster), ISSN 0094-2405, Vol. 33, no 4, p. 933-940Article in journal (Refereed)
    Abstract [en]

    The scatter to primary ratio (SPR) was measured on a scanning multislit full-field digital mammography system for different thickness of breast equivalent material and different tube voltages. Scatter within the detector was measured separately and was found to be the major source of scatter in the assembly. Measured total SPRs below 6% are reported for breast range 3-7 cm. The performance of the multislit assembly is compared to other imaging geometries with different scatter rejection schemes by using the scatter detective quantum efficiency.

  • 264.
    Åslund, Magnus
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    Fredenberg, Erik
    KTH, School of Engineering Sciences (SCI), Physics, Physics of Medical Imaging.
    Cederström, Björn
    KTH, School of Engineering Sciences (SCI), Physics.
    Danielsson, Mats
    KTH, School of Engineering Sciences (SCI), Physics.
    Spectral shaping for photon counting digital mammography2007In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 580, no 2, p. 1046-1049Article in journal (Refereed)
    Abstract [en]

    The spectral shaping properties of conventional filters have been evaluated for a photon counting digital mammography system, and the result has been compared with the theoretical spectrum from a multi-prism X-ray lens (MPL). The absorption filters and the MPL were evaluated using a theoretical model of the system which has been verified experimentally. The spectral shaping performance is quantified with the spectral quantum efficiency (SQE), calculated as the polychromatic signal-difference-to-noise ratio (SDNR) squared over the optimal monochromatic SDNR squared at the same average glandular dose. The MPL increases the SQE by 25% compared to the investigated absorption filter when compared with a Tungsten anode. This translates into a potential dose reduction of 20% at maintained SDNR.

  • 265.
    Þráinsson, Hrafnkell
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Towards a Reliable and Valid Analysis of VO2Off-Kinetics2022Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Non-invasive methods to evaluate skeletal muscle oxidative capacity have beenemerging as a viable substitute for invasive methods in recent years. One ofthose methods utilises near-infrared spectroscopy (NIRS) to calculate V O2mrecovery off-kinetics following an exercise. The data analysis of the measuredsignals from the NIRS is still done manually in a time-consuming and dauntingprocess. The present thesis aimed to develop software, associated with theNIRS method, capable of analysing the recovery from a repeated arterialocclusion protocol following an exercise to assess muscle oxidative capacity.Additionally, to analyse the recovery from ischemic preconditioning as a singletest to assess muscle oxidative capacity. A method that has never been utilisedbefore.11 active, healthy subjects were analysed to calculate their recovery rate.Subjects underwent ischemic preconditioning before exercising for 6 minutesat 80% of gas exchange threshold. A repeated arterial occlusion protocol wascarried out after the exercise. A software was developed in R that utilised linearregression as well as exponential fitting to calculate the recovery rate of eachsubject during both the ischemic preconditioning and the occlusion protocol.The calculated results were compared to predetermined recovery rate results ofeach subject. The calculated results of the repeated arterial occlusion protocolgave similar results to the predetermined ones and even more data on eachsubject’s recovery from an exercise. The calculated results of the ischemicpreconditioning were promising and implied that ischemic preconditioning asa single test can be utilised as a method to assess muscle oxidative capacity.However, further research is required to confirm it. 

    Download full text (pdf)
    fulltext
3456 251 - 265 of 265
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf