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  • 1.
    Bodén, Ida
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Larsson, William
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Nilsson, David
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Forssell, Erik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Naredi, Peter
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Lindholm-Sethson, Britta
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    In vivo skin measurements with a novel probe head for simultaneous skin impedance and near-infrared spectroscopy2011In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 17, no 4, p. 494-504Article in journal (Refereed)
    Abstract [en]

    Background/purpose: Near-infrared (NIR) spectroscopy and skin impedance (IMP) measurements are useful techniques for objective diagnostics of various skin diseases. Here, we present a combined probe head for simultaneous, time-saving NIR spectroscopy and skin impedance measurements. The probe also ensures that both measurements are performed under equal conditions and at the same skin location.

    Methods: Finite element method simulations were performed for evaluation of the impedance. In vivo skin measurements were performed and combined NIR and impedance spectra were analysed by means of multivariate methods with respect to body location, age and gender. The classification rate was determined by a planar discriminant analysis. Reproducibility was investigated by calculation of scatter values and statistical significance between overlapping groups was assessed by the calculation of intra-model distances, q.

    Results: The novel probe yielded rapid reproducible results and was easy to manage. Significant differences between skin locations and to a lesser extent age groups and gender were demonstrated.

    Conclusion: With the novel probe, statistically significant differences between overlapping classes in score plots can be confirmed by calculating intra-model distances. The influence of molecular differences in the skin at different body locations is larger than the influence of gender or age and therefore relevant reference measurements are discussed.

  • 2.
    Bodén, Ida
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Nilsson, David
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Naredi, Peter
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Lindholm-Sethson, Britta
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Characterization of healthy skin using near infrared spectroscopy and skin impedance2008In: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 46, no 10, p. 985-995Article in journal (Refereed)
    Abstract [en]

    Near infrared spectroscopy (NIR) and skin impedance (IMP) spectroscopy are two methods suggested for diagnoses of diseases inducing adverse effects in skin. The reproducibility of these methods and their potential value in non-invasive diagnostics were investigated. Measurements were performed in vivo on healthy skin at five anatomic body sites on eight young women. partial least squares discriminant analysis showed that both methods were useful for classification of the skin characteristics at the sites. Inter-individually the NIR model gave 100% correct classification while the IMP model provided 92%. Intra-individually the NIR model gave 88% correct classification whereas the IMP model did not provide any useful classification. The correct classification was increased to 93% when both datasets were combined, which demonstrates the value of adding information. Partial least squares discriminant analysis gave 72% correct predictions of skin sites while the combined model slightly improved to 73%.

  • 3.
    Brynolfsson, Patrik
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Nilsson, David
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Henriksson, Roger
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Hauksson, Jon
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Karlsson, Mikael
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Garpebring, Anders
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Birgander, Richard
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Trygg, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Nyholm, Tufve
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Asklund, Thomas
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    ADC texture-An imaging biomarker for high-grade glioma?2014In: Medical physics (Lancaster), ISSN 0094-2405, Vol. 41, no 10, p. 101903-Article in journal (Refereed)
    Abstract [en]

    Purpose:

    Survival for high-grade gliomas is poor, at least partly explained by intratumoral heterogeneity contributing to treatment resistance. Radiological evaluation of treatment response is in most cases limited to assessment of tumor size months after the initiation of therapy. Diffusion-weighted magnetic resonance imaging (MRI) and its estimate of the apparent diffusion coefficient (ADC) has been widely investigated, as it reflects tumor cellularity and proliferation. The aim of this study was to investigate texture analysis of ADC images in conjunction with multivariate image analysis as a means for identification of pretreatment imaging biomarkers.

    Methods:

    Twenty-three consecutive high-grade glioma patients were treated with radiotherapy (2 Gy/60 Gy) with concomitant and adjuvant temozolomide. ADC maps and T1-weighted anatomical images with and without contrast enhancement were collected prior to treatment, and (residual) tumor contrast enhancement was delineated. A gray-level co-occurrence matrix analysis was performed on the ADC maps in a cuboid encapsulating the tumor in coronal, sagittal, and transversal planes, giving a total of 60 textural descriptors for each tumor. In addition, similar examinations and analyses were performed at day 1, week 2, and week 6 into treatment. Principal component analysis (PCA) was applied to reduce dimensionality of the data, and the five largest components (scores) were used in subsequent analyses. MRI assessment three months after completion of radiochemotherapy was used for classifying tumor progression or regression.

    Results:

    The score scatter plots revealed that the first, third, and fifth components of the pretreatment examinations exhibited a pattern that strongly correlated to survival. Two groups could be identified: one with a median survival after diagnosis of 1099 days and one with 345 days, p = 0.0001.

    Conclusions:

    By combining PCA and texture analysis, ADC texture characteristics were identified, which seems to hold pretreatment prognostic information, independent of known prognostic factors such as age, stage, and surgical procedure. These findings encourage further studies with a larger patient cohort. (C) 2014 Author(s).

  • 4.
    Brynolfsson, Patrik
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Nilsson, David
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Torheim, Turid
    Asklund, Thomas
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Thellenberg Karlsson, Camilla
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Trygg, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Nyholm, Tufve
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Garpebring, Anders
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Haralick texture features from apparent diffusion coefficient (ADC) MRI images depend on imaging and pre-processing parameters2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 4041Article in journal (Refereed)
    Abstract [en]

    In recent years, texture analysis of medical images has become increasingly popular in studies investigating diagnosis, classification and treatment response assessment of cancerous disease. Despite numerous applications in oncology and medical imaging in general, there is no consensus regarding texture analysis workflow, or reporting of parameter settings crucial for replication of results. The aim of this study was to assess how sensitive Haralick texture features of apparent diffusion coefficient (ADC) MR images are to changes in five parameters related to image acquisition and pre-processing: noise, resolution, how the ADC map is constructed, the choice of quantization method, and the number of gray levels in the quantized image. We found that noise, resolution, choice of quantization method and the number of gray levels in the quantized images had a significant influence on most texture features, and that the effect size varied between different features. Different methods for constructing the ADC maps did not have an impact on any texture feature. Based on our results, we recommend using images with similar resolutions and noise levels, using one quantization method, and the same number of gray levels in all quantized images, to make meaningful comparisons of texture feature results between different subjects.

  • 5. Kuess, Peter
    et al.
    Andrzejewski, Piotr
    Nilsson, David
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Georg, Petra
    Knoth, Johannes
    Susani, Martin
    Trygg, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Helbich, Thomas H.
    Polanec, Stephan H.
    Georg, Dietmar
    Nyholm, Tufve
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
    Association between pathology and texture features of multi parametric MRI of the prostate2017In: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 62, no 19, p. 7833-7854Article in journal (Refereed)
    Abstract [en]

    The role of multi-parametric (mp)MRI in the diagnosis and treatment of prostate cancer has increased considerably. An alternative to visual inspection of mpMRI is the evaluation using histogram-based (first order statistics) parameters and textural features (second order statistics). The aims of the present work were to investigate the relationship between benign and malignant sub-volumes of the prostate and textures obtained from mpMR images. The performance of tumor prediction was investigated based on the combination of histogram-based and textural parameters. Subsequently, the relative importance of mpMR images was assessed and the benefit of additional imaging analyzed. Finally, sub-structures based on the PI-RADS classification were investigated as potential regions to automatically detect maligned lesions. Twenty-five patients who received mpMRI prior to radical prostatectomy were included in the study. The imaging protocol included T2, DWI, and DCE. Delineation of tumor regions was performed based on pathological information. First and second order statistics were derived from each structure and for all image modalities. The resulting data were processed with multivariate analysis, using PCA (principal component analysis) and OPLS-DA (orthogonal partial least squares discriminant analysis) for separation of malignant and healthy tissue. PCA showed a clear difference between tumor and healthy regions in the peripheral zone for all investigated images. The predictive ability of the OPLS-DA models increased for all image modalities when first and second order statistics were combined. The predictive value reached a plateau after adding ADC and T2, and did not increase further with the addition of other image information. The present study indicates a distinct difference in the signatures between malign and benign prostate tissue. This is an absolute prerequisite for automatic tumor segmentation, but only the first step in that direction. For the specific identified signature, DCE did not add complementary information to T2 and ADC maps.

  • 6.
    Lindholm-Sethson, Britta
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Geladi, Paul
    Koeppe II, Roger E
    Jonsson, Oskar
    Nilsson, David
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Nelson, Andrew
    Multivariate Data Analysis for Enhanced Interpretation of Electrochemical Impedance Spectra of Gramicidin-Ion Interactions in Phospholipid Monolayers2007In: Langmuir, Vol. 23, no 9, p. 5029-32Article in journal (Refereed)
    Abstract [en]

    This article describes a multifrequency electrochemical impedance study of phospholipid monolayers on a mercury drop electrode in solutions containing electrolytes and gramicidin derivatives: gramicidin A (gA), gramicidin-BOC (g-BOC), and desformylgramicidin (g-des). The impedance spectra have been studied individually (univariate approach) and also transformed using a multivariate data reduction method (multivariate approach). It was shown that the two approaches are complementary. Thus the formation of K+-conducting channels is observed in gA only, and these channels can be distinguished from an interaction of all gramicidin derivatives with Mg2+. An unknown peptide interaction in the monolayer was observed on a slow time scale.

  • 7.
    Nilsson, David
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Edlund, Ulf
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Pine and spruce roundwood species classification using multivariate image analysis on bark2005In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 59, no 6, p. 689-695Article in journal (Refereed)
    Abstract [en]

    Wood discs from 67 pine and 79 spruce logs were collected from a forest clearing. Three different 24-bit red-green-blue (RGB) images were acquired from the radial surface of each disc. The first image contained bark, the second image was a mixture of bark and wood surface, and the third image consisted only of wood surface. The image texture was compressed into vectors of Fourier-transformed wavelet coefficients. These were assembled in matrices and analysed by principal component analysis (PCA) and partial least-squares projections to latent structures (PLS). Classification using Fourier-transformed wavelet scales showed that the wood species could be predicted with 90% accuracy. A thorough examination of this classification showed that the predicting power of these models was mostly due to wavelet scales that represented the mean value of each colour channel. The prediction accuracy that could be obtained from coefficients representing image texture was generally low. The use of grey-level co-occurrence matrices prior to the wavelet transformation showed, however, that it is possible to classify the wood species of pine and spruce with an accuracy approaching 100%.

  • 8.
    Nilsson, David
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Edlund, Ulf
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Elg-Christofferson, Kristina
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sjöström, Michael
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Agnemo, Roland
    The effect of designed wood storage on the brightness of bleached and unbleached thermo mechanical pulp2003In: Nordic Pulp & Paper Research Journal, Vol. 18, no 4, p. 369-76Article in journal (Refereed)
    Abstract [en]

    60 Norway Spruce (Picea abies) logs were stored in climate chambers for 14 weeks in order to investigate the effect of wood storage on the brightness of thermo mechanical pulp. The storage conditions were altered according to an experimental design comprised of five factors; light, watering, temperature, tree growth and debarking. Wood samples were collected during the storage period and refined into thermo mechanical pulp. ISO brightness values were measured for the unbleached, the dithionite bleached and the hydrogen peroxide bleached thermo mechanical pulp samples that were refined from the stored wood. The decrease in ISO brightness after 14 weeks of wood storage was significant for some of the samples bleached with dithionite. It was found that the interaction between watering and light had a significant negative effect on the brightness of the unbleached and dithionite bleached samples. The samples bleached with hydrogen peroxide generally showed a more consistent ISO brightness. Only watering and temperature had a significant effect on the brightness of peroxide bleached thermo, mechanical pulp.

  • 9.
    Nilsson, David
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Edlund, Ulf
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sjöström, Michael
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Agnemo, Roland
    Prediction of thermo mechanical pulp brightness using NIR spectroscopy on wood raw material2005In: Paperi ja puu, ISSN 0031-1243, Vol. 87, no 2, p. 102-109Article in journal (Refereed)
    Abstract [en]

    Partial Least Squares regression to latent structures was used to find a correlation between near-infrared reflectance spectra of samples of milled Norway Spruce (Picea abies) and ISO brightness of bleached thermo mechanical pulp. Logs of spruce were stored in climate chambers with different conditions for 14 weeks. A factorial design based on five variables was constructed to control the storage and to provide different brightness properties of the stored spruce logs. Wood samples were collected during the storage and they were analysed with near-infrared reflectance spectroscopy and later refined to thermo mechanical pulp. The pulp was bleached with both hydrogen peroxide and sodium dithionite. The ISO brightness of the bleached pulp was correlated to the near-infrared spectra of the untreated samples using Partial Least Squares regression to latent structures. The modelling showed that it is possible to predict the ISO brightness of bleached thermo mechanical pulp from near-infrared spectra of original wood raw material.

  • 10.
    Nilsson, David
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Persson, Erik
    Classification of the softwood species spruce and pine using near-infrared reflectance measurements on bark combined with multivariate data analysisManuscript (Other academic)
  • 11.
    Peolsson, A.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Medical and Health Sciences, Physiotherapy, Linköping University, Sweden; Centre for Clinical Research Sörmland, Uppsala University, Sweden.
    Peterson, G.
    Trygg, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Nilsson, David
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Altered mechanical deformation of the trapezius and multifidus muscles registered with ultrasonography in women with chronic whiplash-associated disorders2016In: Manual Therapy, ISSN 1356-689X, E-ISSN 1532-2769, Vol. 25, p. e58-Article in journal (Refereed)
    Abstract [en]

    Background: The deformation and deformation rate of the dorsal neck muscle layers in individuals with chronic whiplash associated disorders (WAD) is rarely evaluated, and the mechanical behaviour during dynamic neck extension remains to be investigated.

    Purpose: To compare the deformation and deformation rate of dorsal neck muscles (trapezius, splenius capitis, semispinalis capitis and cervicis, and multifidus) in women with chronic WAD compared with healthy controls during a dynamic resisted neck extension.

    Methods: Nine women with chronic grade 2 and 3 WAD (mean age 38 years, standard deviation [SD] 11.3) and nine age- and gender-matched healthy controls (mean age 38 years, SD 11.6) participated in this cross-sectional, controlled study. Ultrasonography movies and post-process speckle tracking were used to investigate real-time mechanical dorsal neck muscle behaviour at the C4 segmental level during a low-loaded dynamic standardized neck extension. Deformation (longitudinal shortening and elongation) and deformation rate (speed of deformation) were calculated during the entire exercise sequence.

    Results: There were significant differences between the WAD and control groups in total deformation for the trapezius (p < 0.04) and multifidus (p < 0.03). The WAD group showed more shortening in the deformation pattern during the concentric contraction phase in the trapezius muscle, and during both the concentric and eccentric phase in the multifidus muscle compared to healthy controls. There were no other significant differences between groups either in deformation or deformation rate.

    Conclusion: There were altered mechanical deformations of the trapezius and multifidus muscles, with preliminary evidence for overuse in individuals with WAD compared to healthy controls. The findings must be interpreted with caution due to the small sample size.

    Implications: An ultrasound investigation made it possible to non-invasively capture multi-layered muscles in real time, adding new information of value for clinical practice of patients with WAD, which may impact future rehabilitation.

  • 12. Peolsson, Anneli
    et al.
    Peterson, Gunnel
    Trygg, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Nilsson, David
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Multivariate analysis of ultrasound-recorded dorsal strain sequences: Investigation of dynamic neck extensions in women with chronic whiplash associated disorders2016In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, article id 30415Article in journal (Refereed)
    Abstract [en]

    Whiplash Associated Disorders (WAD) refers to the multifaceted and chronic burden that is common after a whiplash injury. Tools to assist in the diagnosis of WAD and an increased understanding of neck muscle behaviour are needed. We examined the multilayer dorsal neck muscle behaviour in nine women with chronic WAD versus healthy controls during the entire sequence of a dynamic low-loaded neck extension exercise, which was recorded using real-time ultrasound movies with high frame rates. Principal component analysis and orthogonal partial least squares were used to analyse mechanical muscle strain (deformation in elongation and shortening). The WAD group showed more shortening during the neck extension phase in the trapezius muscle and during both the neck extension and the return to neutral phase in the multifidus muscle. For the first time, a novel non-invasive method is presented that is capable of detecting altered dorsal muscle strain in women with WAD during an entire exercise sequence. This method may be a breakthrough for the future diagnosis and treatment of WAD.

  • 13.
    Peterson, Gunnel
    et al.
    Eskilstuna, Sweden; Linköping, Sweden.
    Dedering, Åsa
    Karolinska Institutet, Sweden; Karolinska University Hospital, Sweden.
    Andersson, Erika
    Linköping, Sweden.
    Nilsson, David
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Trygg, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Peolsson, Michael
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wallman, Thorne
    Eskilstuna, Sweden; Uppsala, Swe.
    Peolsson, Anneli
    Linköping, Sweden.
    Altered ventral neck muscle deformation for individuals with whiplash associated disorder compared to healthy controls: A case-control ultrasound study2015In: Manual Therapy, ISSN 1356-689X, E-ISSN 1532-2769, Vol. 20, no 2, p. 319-327Article in journal (Refereed)
    Abstract [en]

    Previous studies have shown altered neck muscle function in individuals with chronic whiplash associated disorder (WAD). However, we lack real-time investigations with non-invasive methods that can distinguish between the different ventral neck muscle layers. This study investigated deformations and deformation rates in the sternocleidomastoid (SCM), longus capitis (Lcap), and longus colli (Lco) muscles with real-time ultrasonography. Twenty-six individuals with WAD were compared with 26 controls, matched for age and sex. Ultrasound imaging of the SCM, Lcap, and Lco were recorded during 10 repetitive arm elevations. The first and tenth arm elevations were post-process analyzed with speckle tracking. There were few significant differences in the deformations or deformation rates in the SCM, Lcap, and Lco between the WAD and control group. In controls, deformations and deformation rates showed linear positive relationships between SCM/Lcap, SCM/Lco, and Lcap/Lco which increased from the first arm elevation (R-2 = 0.14-0.70); to the tenth arm elevation (R-2 = 0.51-0.71). The WAD group showed similar or weaker linear relationship (R-2 < 0.19) during the tenth compared to the first (R-2 < 0.44) arm elevation except for deformations in Lcap/Lco (R-2 = 0.13-0.57). This result indicated that deformations and deformation rates in one muscle were correlated by similar deformations and deformation rates in other neck muscles in the control group, but this interplay between muscles was not found in the WAD group. (C) 2014 Elsevier Ltd. All rights reserved.

  • 14. Peterson, Gunnel
    et al.
    Nilsson, David
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Peterson, Simon
    Dedering, Åsa
    Trygg, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wallman, Thorne
    Peolsson, Anneli
    Changes in dorsal neck muscle function in individuals with chronic whiplash-associated disorders: a real-time ultrasound case-control study2016In: Ultrasound in Medicine and Biology, ISSN 0301-5629, E-ISSN 1879-291X, Vol. 42, no 5, p. 1090-1102Article in journal (Refereed)
    Abstract [en]

    Impaired neck muscle function leads to disability in individuals with chronic whiplash-associated disorder (WAD), but diagnostic tools are lacking. In this study, deformations and deformation rates were investigated in five dorsal neck muscles during 10 arm elevations by ultrasonography with speckle tracking analyses. Forty individuals with chronic WAD (28 women and 12 men, mean age = 37 y) and 40 healthy controls matched for age and sex were included. The WAD group had higher deformation rates in the multifidus muscle during the first (p < 0.04) and 10th (only women, p < 0.01) arm elevations compared with the control group. Linear relationships between the neck muscles for deformation rate (controls: R-2 = 0.24-0.82, WAD: R-2 = 0.05-0.74) and deformation of the deepest muscles (controls: R-2 = 0.61-0.32, WAD: R-2 = 0.15-0.01) were stronger for women in the control group versus women with WAD, indicating there is altered interplay between dorsal neck muscles in chronic WAD. 

  • 15. Peterson, Gunnel
    et al.
    Nilsson, David
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Trygg, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Falla, Deborah
    Dedering, Åsa
    Wallman, Thorne
    Peolsson, Anneli
    Novel insights into the interplay between ventral neck muscles in individuals with whiplash-associated disorders2015In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 5, article id 15289Article in journal (Refereed)
    Abstract [en]

    Chronic whiplash-associated disorder (WAD) is common after whiplash injury, with considerable personal, social, and economic burden. Despite decades of research, factors responsible for continuing pain and disability are largely unknown, and diagnostic tools are lacking. Here, we report a novel model of mechanical ventral neck muscle function recorded from non-invasive, real-time, ultrasound measurements. We calculated the deformation area and deformation rate in 23 individuals with persistent WAD and compared them to 23 sex-and age-matched controls. Multivariate statistics were used to analyse interactions between ventral neck muscles, revealing different interplay between muscles in individuals with WAD and healthy controls. Although the cause and effect relation cannot be established from this data, for the first time, we reveal a novel method capable of detecting different neck muscle interplay in people with WAD. This non-invasive method stands to make a major breakthrough in the assessment and diagnosis of people following a whiplash trauma.

  • 16. Peterson, Gunnel
    et al.
    Nilsson, David
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Trygg, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Peolsson, Anneli
    Neck-specific exercise improves impaired interactions between ventral neck muscles in chronic whiplash: A randomized controlled ultrasound study2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 9649Article in journal (Refereed)
    Abstract [en]

    Chronic pain and disability is common in whiplash-associated disorders (WAD), leading to personal suffering, sick leave, and social cost. The cervical spine is heavily dependent on muscular support and whiplash injury can cause damage to the neck muscles, but diagnostic tools to measure neck muscle impairment and evaluate exercise interventions are lacking. Therefore, the present study investigated ventral neck muscle interactions in 26 individuals with chronic WAD randomized to neck-specific exercise (NSE) or remaining on a waiting list (WL) in 3 months. We performed real-time, non-invasive ultrasound measurements with speckle tracking analysis and calculated the deformation area and deformation rate in three ventral neck muscles. Multivariate statistics were used to analyse interactions between the muscles. After 3 months of NSE, significant improvements were observed in neck muscle interactions and pain intensity in the NSE group compared to the WL group. Thus, this study demonstrates that non-invasive ultrasound can be a diagnostic tool for muscle impairment and used to evaluate exercise interventions in WAD and stands to make a breakthrough for better management in chronic WAD.

  • 17. Peterson, Gunnel
    et al.
    O'Leary, Shaun
    Nilsson, David
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Moodie, Katherine
    Tucker, Kylie
    Trygg, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Peolsson, Anneli
    Ultrasound imaging of dorsal neck muscles with speckle tracking analyses: the relationship between muscle deformation and force2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 13688Article in journal (Refereed)
    Abstract [en]

    The development of methods of non-invasive measurement of neck muscle function remains a priority in the clinical sciences. In this study, dorsal neck muscle deformation vs time curves (deformation area) were evaluated against incremental force, recorded from non-invasive real-time ultrasound measurement. The results revealed subject-specific moderate to strong linear or non-linear relationships between deformation and force. Test-retest variability showed strong reliability for all five neck muscles summed together and fair to good reliability for the five muscles evaluated separately. Multivariate statistics were used to analyse the interactions between the dorsal neck muscles during different percentages of maximal voluntary contraction (MVC). Low force (10-20% MVC) was related to muscle shortening; higher force (40-80% MVC) showed combination of shortening and elongation deformation in the muscle interactions. The muscle interactions during isometric MVC test were subject-specific, with different combinations and deformations of the five neck muscles. Force >= 40% MVC were associated with a forward movement of the cervical spine that affected the ultrasound measurement of the dorsal neck muscles. Ultrasound with speckle-tracking analyses may be best used to detect low levels (<40% MVC) of neck muscle activity.

  • 18.
    Skotare, Tomas
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Nilsson, David
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Xiong, Shaojun
    Geladi, Paul
    Trygg, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Corporate Research, Sartorius AG, 37079 Göttingen, Germany.
    Joint and unique multiblock analysis for integration and calibration transfer of NIR instruments2019In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 91, no 5, p. 3516-3524Article in journal (Refereed)
    Abstract [en]

    In the present paper, we introduce an end-to-end workflow called joint and unique multiblock analysis (JUMBA), which allows multiple sources of data to be analyzed simultaneously to better understand how they complement each other. In near-infrared (NIR) spectroscopy, calibration models between NIR spectra and responses are used to replace wet-chemistry methods, and the models tend to be instrument-specific. Calibration-transfer techniques are used for standardization of NIR-instrumentation, enabling the use of one model on several instruments. The current paper investigates both the similarities and differences among a variety of NIR instruments using JUMBA. We demonstrate JUMBA on both a previously unpublished data set in which five NIR instruments measured mushroom substrate and a publicly available data set measured on corn samples. We found that NIR spectra from different instrumentation largely shared the same underlying structures, an insight we took advantage of to perform calibration transfer. The proposed JUMBA transfer displayed excellent calibration-transfer performance across the two analyzed data sets and outperformed existing methods in terms of both prediction accuracy and stability. When applied to a multi-instrument environment, JUMBA transfer can integrate all instruments in the same model and will ensure higher consistency among them compared with existing calibration-transfer methods.

  • 19.
    Skotare, Tomas
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sjögren, Rickard
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Surowiec, Izabella
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Nilsson, David
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Trygg, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Sartorius Stedim Data Analytics, 907 36 Umeå, Sweden.
    Visualization of descriptive multiblock analysis2018In: Journal of Chemometrics, ISSN 0886-9383, E-ISSN 1099-128XArticle in journal (Refereed)
    Abstract [en]

    Abstract Understanding and making the most of complex data collected from multiple sources is a challenging task. Data integration is the procedure of describing the main features in multiple data blocks, and several methods for multiblock analysis have been previously developed, including OnPLS and JIVE. One of the main challenges is how to visualize and interpret the results of multiblock analyses because of the increased model complexity and sheer size of data. In this paper, we present novel visualization tools that simplify interpretation and overview of multiblock analysis. We introduce a correlation matrix plot that provides an overview of the relationships between blocks found by multiblock models. We also present a multiblock scatter plot, a metadata correlation plot, and a variation distribution plot, that simplify the interpretation of multiblock models. We demonstrate our visualizations on an industrial case study in vibration spectroscopy (NIR, UV, and Raman datasets) as well as a multiomics integration study (transcript, metabolite, and protein datasets). We conclude that our visualizations provide useful tools to harness the complexity of multiblock analysis and enable better understanding of the investigated system.

  • 20.
    Souihi, Nabil
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Nilsson, David
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Josefson, Mats
    Trygg, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Near-infrared chemical imaging (NIR-CI) on roll compacted ribbons and tablets - multivariate mapping of physical and chemical properties2015In: International Journal of Pharmaceutics, ISSN 0378-5173, E-ISSN 1873-3476, Vol. 483, no 1-2, p. 200-211Article in journal (Refereed)
    Abstract [en]

    Near-infrared chemical imaging (NIR-CI) is an attractive technique within the pharmaceutical industry, where tools are continuously in demand to assess the quality of the intermediate and final products. The present paper demonstrates how NIR-CI in combination with multivariate methods was utilized to spatially map physical properties and content of roll compacted ribbons and tablets. Additionally, extracted textural parameters from tablet images were correlated to the design parameters of the roll compaction process as well as to the physical properties of the granules. The results established the use of NIR-CI as a complementary nondestructive tool to determine the ribbon density and map the density distribution across the width and along the length of the ribbons. For the tablets, the compaction pressure developed during compression increased with the lateral distance from the center. Therefore, NIR-CI can be an effective tool to provide information about the spatial distribution of the compaction pressures on the surface of the tablet. Moreover, low roll compaction roll force correlated to a heterogeneous type of texture in the API chemical image. Overall, texture analysis of the tablets enabled efficient investigation of the spatial variation and could be used to advance process understanding. Finally, orthogonal projections to latent structures (O2PLS) model facilitated the understanding of the interrelationships between textural features, design parameters and physical properties data by separately joint and unique variations.

  • 21.
    Wiklund, Susanne
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Nilsson, David
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Eriksson, Lennart
    Umetrics, Umeå, Sweden.
    Sjöström, Michael
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wold, Svante
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Faber, Klaas
    Chemometry Consultancy, Rubensstraat 7, 6717 VD Ede, The Netherlands.
    A randomization test for PLS component selection2007In: Journal of Chemometrics, ISSN 0886-9383, E-ISSN 1099-128X, Vol. 21, no 10-11, p. 427-439Article in journal (Refereed)
    Abstract [en]

    During the last two decades, a number of methods have been developed and evaluated for selecting the optimal number of components in a PLS model. In this paper, a new method is introduced that is based on a randomization test. The advantage of using a randomization test is that in contrast to cross validation (CV), it requires no exclusion of data, thus avoiding problems related to data exclusion, for example in designed experiments. The method is tested using simulated data sets for which the true dimensionality is clearly defined and also compared to regularly used methods for 10 real data sets. The randomization test works as a good statistical selection tool in combination with other selection rules. It also works as an indicator when the data require a pre-treatment.

1 - 21 of 21
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