| 1. |
- Cornelissen, R., et al.
(författare)
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The Cell Envelope Structure of Cable Bacteria
- 2018
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Ingår i: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Cable bacteria are long, multicellular micro-organisms that are capable of transporting electrons from cell to cell along the longitudinal axis of their centimeter-long filaments. The conductive structures that mediate this long-distance electron transport are thought to be located in the cell envelope. Therefore, this study examines in detail the architecture of the cell envelope of cable bacterium filaments by combining different sample preparation methods (chemical fixation, resin-embedding, and cryo-fixation) with a portfolio of imaging techniques (scanning electron microscopy, transmission electron microscopy and tomography, focused ion beam scanning electron microscopy, and atomic force microscopy). We systematically imaged intact filaments with varying diameters. In addition, we investigated the periplasmic fiber sheath that remains after the cytoplasm and membranes were removed by chemical extraction. Based on these investigations, we present a quantitative structural model of a cable bacterium. Cable bacteria build their cell envelope by a parallel concatenation of ridge compartments that have a standard size. Larger diameter filaments simply incorporate more parallel ridge compartments. Each ridge compartment contains a similar to 50 nm diameter fiber in the periplasmic space. These fibers are continuous across cell-to-cell junctions, which display a conspicuous cartwheel structure that is likely made by invaginations of the outer cell membrane around the periplasmic fibers. The continuity of the periplasmic fibers across cells makes them a prime candidate for the sought-after electron conducting structure in cable bacteria.
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| 2. |
- Ling, M. L., et al.
(författare)
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Effects of Ice Nucleation Protein Repeat Number and Oligomerization Level on Ice Nucleation Activity
- 2018
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Ingår i: Journal of Geophysical Research: Atmospheres. - 2169-8996. ; 123:3, s. 1802-1810
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Tidskriftsartikel (refereegranskat)abstract
- Ice nucleation active bacteria have attracted particular attention due to their unique ability to produce specific ice nucleation proteins (INpros), which are the most efficient ice nuclei known as they induce nucleation at temperatures close to 0°C. Our model bacterium Pseudomonas syringae strain R10.79 produced INpros containing 67 tandem repeats, forming the proposed ice-binding surface. To understand the role of the INpro repeats as well as the role of intermolecular interactions between INpros for their ice nucleation behavior, we produced a truncated version of the protein with only 16 tandem repeats (INpro16R). The purified INpro16R produced oligomers of varying sizes. Immersion freezing ice nucleation behavior of purified INpro16R was characterized by droplet-freezing assays and in the Leipzig Aerosol Cloud Interaction Simulator. Predominant INpro16R oligomers introduced into Leipzig Aerosol Cloud Interaction Simulator as single particles with diameters of 50 nm or 70 nm were ice nucleation active at temperatures of -26°C and -24°C, respectively. These are much lower temperatures compared to that of intact INpros (-12°C). The data clearly indicated that the number of repeats determines the ice nucleation temperature. In addition, ice nucleation between -9°C and -10°C, comparable to the activity of intact INpro, was caused by higher-order INpro16R oligomers. This supported previous observations that INpro oligomerization increases the ice-binding surface, thereby affecting ice nucleation activity. In conclusion, both repeat number and oligomerization contribute in a seemingly independent manner to the nucleation mechanism of INpros.
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| 3. |
- Axelsen, M. B., et al.
(författare)
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Responsiveness of different dynamic contrast-enhanced magnetic resonance imaging approaches: a post-hoc analysis of a randomized controlled trial of certolizumab pegol in rheumatoid arthritis
- 2020
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Ingår i: Scandinavian Journal of Rheumatology. - : Informa UK Limited. - 0300-9742 .- 1502-7732. ; 49:2, s. 105-111
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The aim was to explore dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) as an early marker of therapeutic response in patients with rheumatoid arthritis (RA) starting treatment with certolizumab pegol (CZP). Method: In 40 RA patients initiating CZP (27 patients) or 2 weeks of placebo (PCB) followed by CZP (13 patients), DCE-MRI of the metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints was performed at weeks 0, 1, 2, 4, 8, and 16. Using semi-automated software, three methods for drawing volume regions of interest (ROIs) in MCP2-5 and PIP2-5 were applied: 'Standard' (slices: all; joints: MCP2-5 together and PIP2-5 together), 'Detailed' (slices: slices with high-quality visualization; joints: as Standard), and 'Single-joint' (slices: as Detailed; joints: each joint separately). The number of enhancing voxels (Nvoxel), initial rate of enhancement (IRE), and maximum enhancement (ME) were extracted and analysed for each method. Results: Nvoxel in MCP2-5, and IRE and ME in PIP2-5 decreased statistically significantly (Wilcoxon rank-sum test, p < 0.02-0.03) after 16 weeks of treatment for the Standard method. Nvoxel and ME decreased significantly more in the CZP group than in the PCB group after 1 week of treatment, but not at later time-points. There were no significant changes for DCE-MRI parameters for the Detailed and Single-joint methods. Conclusions: Certain DCE-MRI parameters detected decreased inflammation during CZP treatment in RA patients. Using specific criteria for ROIs, as in the Detailed and Single-joint methods, decreased the statistical power and could not show any changes over time.
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| 4. |
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| 5. |
- Boesen, Jannik, et al.
(författare)
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The "success story" of peasant tobacco production in Tanzania : the political economy of a commodity producing peasantry
- 1979
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This book studies how Tanzania in a period of 25-30 years became a tobacco producer and exporter. But its emphasis is on production, and therefore on the producers. It analyses the processes that made Tanzanians into peasant producers of tobacco for the international market. The dynamics of the organization of production under changing conditions of production. The effects on the development of productive forces, reproduction processes and the standard of living among the producers.
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| 6. |
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| 7. |
- Clausen, Stine Haugaard, et al.
(författare)
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Two-year MRI-defined structural damage and patient-reported outcomes following surgery or exercise for meniscal tears in young adults
- 2023
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Ingår i: British journal of sports medicine. - 0306-3674. ; 57:24
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To investigate potential differences in structural knee joint damage assessed by MRI and patient-reported outcomes (PROMs) at 2-year follow-up between young adults randomised to early surgery or exercise and education with optional delayed surgery for a meniscal tear. Methods: A secondary analysis of a multicentre randomised controlled trial including 121 patients (18-40 years) with an MRI-verified meniscal tear. For this study, only patients with 2-year follow-up were included. The main outcomes were the difference in worsening of structural knee damage, assessed by MRI using the Anterior Cruciate Ligament OsteoArthrits Score, and the difference in change in the mean score of four Knee Injury and Osteoarthritis Outcome Score (KOOS4) subscales covering pain, symptoms, function in sport and recreation, and quality of life, from baseline to 2 years. Results: In total, 82/121 (68%) patients completed the 2-year follow-up (39 from the surgical group and 43 from the exercise group). MRI-defined cartilage damage had developed or progressed in seven (9.1%) patients and osteophytes developed in two (2.6%) patients. The worsening of structural damage from baseline to 2-year follow-up was similar between groups. The mean (95% CI) adjusted differences in change in KOOS4 between intervention groups from baseline to 2 years was -1.4 (-9.1, 6.2) points. The mean improvement in KOOS4 was 16.4 (10.4, 22.4) in the surgical group and 21.5 (15.0, 28.0) in the exercise group. No between group differences in improvement were found in the KOOS subscales. Conclusions: The 2-year worsening of MRI-defined structural damage was limited and similar in young adult patients with a meniscal tear treated with surgery or exercise with optional delayed surgery. Both groups had similar clinically relevant improvements in KOOS4, suggesting the choice of treatment strategy does not impact 2-year structural knee damage or PROMs. Trial registration number: NCT02995551.
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| 8. |
- Hangaard, Stine, et al.
(författare)
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Delayed Gadolinium-Enhanced MRI of Menisci and Cartilage (dGEMRIM/dGEMRIC) in Obese Patients With Knee Osteoarthritis : Cross-Sectional Study of 85 Obese Patients With Intra-articular Administered Gadolinium Contrast
- 2018
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Ingår i: Journal of Magnetic Resonance Imaging. - : Wiley. - 1053-1807. ; 48:6, s. 1700-1706
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Tidskriftsartikel (refereegranskat)abstract
- Background: Early cartilage changes in knee osteoarthritis (OA) can be assessed by both intravenous (i.v.) and intra-articular (i.a.) delayed gadolinium-enhanced MRI of cartilage (dGEMRIC). Purpose: To examine the relationship between i.a. dGEMRIC and delayed gadolinium-enhanced MRI of menisci (dGEMRIM), and to investigate if the approach can be used to assess the morphological degeneration of menisci in obese patients with knee OA. Study Type: Cross-sectional. Population: Eighty-five obese patients with knee OA. Field Strength/Sequences: 1.5T. Inversion recovery sequence with four inversion times. Assessment: T1 relaxation times were calculated for posterior weight-bearing femoral cartilage and the posterior horns of the menisci. Meniscus degeneration sum score (0–2) was assessed as increased signal/no signal (1/0) and tear/no tear (1/0). Statistical Tests: T1 relaxation times were compared using Student's t-test. Comparison of cartilage and meniscus T1 relaxation times was done by regression analysis. Analysis of variance (ANOVA) was used for comparison of meniscal T1 relaxation times among the three summed morphological scores (0–2). Statistical analyses were performed with a level of significance at 0.05. Results: For lateral menisci, morphology sum scores of 0, 1, and 2 were found in 13, 58, and 14 patients and for medial menisci in 2, 30, and 30 patients, respectively. Mean T1 relaxation times were 441 msec, 480 msec, and 497 msec for cartilage, lateral menisci, and medial menisci, respectively. T1 relaxation times for the menisci were similar (P = 0.53), and a weak correlation was found between dGEMRIC and dGEMRIM in the lateral compartments (R = 0.26). Comparing dGEMRIM between different morphology sum scores showed no differences (P > 0.4). Data Conclusion: I.a. dGEMRIM showed no correlation between the degree of meniscal degeneration and meniscus T1 relaxation times. I.a. dGEMRIM do not seem to deliver useful information about meniscus degeneration to be suitable for clinical applications, but i.a. dGEMRIC may still be considered an alternative contrast-saving method for cartilage. Level of Evidence: 3. Technical Efficacy: Stage 3. J. Magn. Reson. Imaging 2018;00:000–000.
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| 9. |
- Henriksen, M., et al.
(författare)
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Is increased joint loading detrimental to obese patients with knee osteoarthritis? A secondary data analysis from a randomized trial
- 2013
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Ingår i: Osteoarthritis and Cartilage. - : Elsevier BV. - 1063-4584. ; 21:12, s. 1865-1875
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To investigate whether increased knee joint loading due to improved ambulatory function and walking speed following weight loss achieved over 16 weeks accelerates symptomatic and structural disease progression over a subsequent 1 year weight maintenance period in an obese population with knee osteoarthritis (OA). Methods: Data from a prospective study of weight loss in obese patients with knee OA (the CARtilage in obese knee OsteoarThritis (CAROT) study) were used to determine changes in knee joint compressive loadings (model estimated) during walking after a successful 16 week weight loss intervention. The participants were divided into 'Unloaders' (participants that reduced joint loads) and 'Loaders' (participants that increased joint loads). The primary symptomatic outcome was changes in knee symptoms, measured with the Knee injury and Osteoarthritis Outcome Score (KOOS) questionnaire, during a subsequent 52 weeks weight maintenance period. The primary structural outcome was changes in tibiofemoral cartilage loss assessed semi-quantitatively (Boston Leeds Knee Osteoarthritis Score (BLOKS) from MRI after the 52 weight maintenance period. Results: 157 participants (82% of the CAROT cohort) with medial and/or lateral knee OA were classified as Unloaders (n = 100) or Loaders (n = 57). The groups showed similar significant changes in symptoms (group difference: 2.4 KOOS points [95% CI 6.8:1.91) and cartilage loss (group difference: 0.06 BLOKS points [95% CI 0.22:0.11) after 1 year, with no statistically significant differences between Loaders and Unloaders. Conclusion: For obese patients undergoing a significant weight loss, increased knee joint loading for 1 year was not associated with accelerated symptomatic and structural disease progression compared to a similar weight loss group that had reduced ambulatory compressive knee joint loads. Clinicaltrials.gov: NCT00655941. (C) 2013 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.
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