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| 2. |
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| 3. |
- Duffy, J. Emmett, et al.
(författare)
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Toward a Coordinated Global Observing System for Seagrasses and Marine Macroalgae
- 2019
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Ingår i: Frontiers in Marine Science. - : Frontiers Media S.A.. - 2296-7745. ; 6
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Forskningsöversikt (refereegranskat)abstract
- In coastal waters around the world, the dominant primary producers are benthic macrophytes, including seagrasses and macroalgae, that provide habitat structure and food for diverse and abundant biological communities and drive ecosystem processes. Seagrass meadows and macroalgal forests play key roles for coastal societies, contributing to fishery yields, storm protection, biogeochemical cycling and storage, and important cultural values. These socio-economically valuable services are threatened worldwide by human activities, with substantial areas of seagrass and macroalgal forests lost over the last half-century. Tracking the status and trends in marine macrophyte cover and quality is an emerging priority for ocean and coastal management, but doing so has been challenged by limited coordination across the numerous efforts to monitor macrophytes, which vary widely in goals, methodologies, scales, capacity, governance approaches, and data availability. Here, we present a consensus assessment and recommendations on the current state of and opportunities for advancing global marine macrophyte observations, integrating contributions from a community of researchers with broad geographic and disciplinary expertise. With the increasing scale of human impacts, the time is ripe to harmonize marine macrophyte observations by building on existing networks and identifying a core set of common metrics and approaches in sampling design, field measurements, governance, capacity building, and data management. We recommend a tiered observation system, with improvement of remote sensing and remote underwater imaging to expand capacity to capture broad-scale extent at intervals of several years, coordinated with strati fied in situ sampling annually to characterize the key variables of cover and taxonomic or functional group composition, and to provide ground-truth. A robust networked system of macrophyte observations will be facilitated by establishing best practices, including standard protocols, documentation, and sharing of resources at all stages of work flow, and secure archiving of open-access data. Because such a network is necessarily distributed, sustaining it depends on close engagement of local stakeholders and focusing on building and long-term maintenance of local capacity, particularly in the developing world. Realizing these recommendations will producemore effective, efficient, and responsive observing, a more accurate global picture of change in vegetated coastal systems, and stronger international capacity for sustaining observations.
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| 6. |
- Hakimi Hashjin, L., et al.
(författare)
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The effect of educational intervention based on the protective motivation theory on awareness and early detection behaviours of breast cancer in women
- 2022
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Ingår i: International Journal of Health Promotion and Education. - : Informa UK Limited. - 1463-5240 .- 2164-9545.
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Tidskriftsartikel (refereegranskat)abstract
- ‘Cancer control and early detection’ is one of the priority programs of the World Health Organization. This quasi-experimental study aimed to investigate the effect of educational intervention, based on the Protection Motivation Theory (PMT), on awareness and early detection behaviours of breast cancer (BC) in women. The eligible women were randomly selected through electronic health records, and divided into the intervention (IG) (n = 45) and control groups (CG) (n = 45). Data were collected in three phases: baseline (T1), immediately (T2) and two-month (T3) after the PMT-based intervention using four questionnaires of Demographic-Clinical Information, Awareness of BC Warning Signs, Awareness of BC Early Detection Behaviours and Modified Early Cancer Detection Behaviours – BC version. Results showed that the PMT-based education influenced the awareness and behaviours of participants in the IG group compared with the CG over time (p < 0.001). The mean and standard deviation of variables improved in the IG in comparison to the CG from T1 to T3: ‘awareness of BC warning signs’ [IG: (T1: 68.50 ± 5.47) to (T3: 89.40 ± 3.50)] [CG: (T1: 69.70 ± 5.87) to (T3: 67.40 ± 2.42)], ‘awareness of early detection behaviours’ [IG: (T1: 78.65 ± 4.47) to (T3: 89.55 ± 4.74)] [CG: (T1: 79.20 ± 5.45) to (T3: 84.10 ± 2.89)] and ‘protection behaviours’ [IG: (T1: 65.01 ± 23.99) to (T3: 98.15 ± 12.20)] [CG: (T1: 56.94 ± 20.85) to (T3: 57.68 ± 21.01)]. Thus, women in this context should be motivated and empowered towards protective health behaviours for early detection of BC. It is suggested that healthcare providers develop PMT-based programs for BC early detection in women in different settings of the community.
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| 7. |
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| 8. |
- Li, Hao, 1984-, et al.
(författare)
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Unlocking the human inner ear for therapeutic intervention
- 2022
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- The human inner ear contains minute three-dimensional neurosensory structures that are deeply embedded within the skull base, rendering them relatively inaccessible to regenerative therapies for hearing loss. Here we provide a detailed characterisation of the functional architecture of the space that hosts the cell bodies of the auditory nerve to make them safely accessible for the first time for therapeutic intervention. We used synchrotron phase-contrast imaging which offers the required microscopic soft-tissue contrast definition while simultaneously displaying precise bony anatomic detail. Using volume-rendering software we constructed highly accurate 3-dimensional representations of the inner ear. The cell bodies are arranged in a bony helical canal that spirals from the base of the cochlea to its apex; the canal volume is 1.6 mu L but with a diffusion potential of 15 mu L. Modelling data from 10 temporal bones enabled definition of a safe trajectory for therapeutic access while preserving the cochlea's internal architecture. We validated the approach through surgical simulation, anatomical dissection and micro-radiographic analysis. These findings will facilitate future clinical trials of novel therapeutic interventions to restore hearing.
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| 9. |
- Quintana, M., et al.
(författare)
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Assessment of the longitudinal and circumferential left ventricular function at rest and during exercise in healthy elderly individuals by tissue-Doppler echocardiography : relationship with heart rate
- 2004
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Ingår i: Clinical Science. - : Portland Press Ltd.. - 0143-5221 .- 1470-8736. ; 106:5, s. 451-457
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Tidskriftsartikel (refereegranskat)abstract
- Tissue-Doppler echocardiography (TDE) has been introduced to quantify stress echocardiography by means of assessing the left ventricular (LV) segmental myocardial velocities and excursion. The interaction between LV long- and short-axis function during physical exercise has not been elucidated completely. The aim of the present study was to investigate long- and short-axis LV function, as assessed by myocardial velocities and excursions at rest and during exercise and its possible relationship with heart rate in healthy elderly individuals by TIDE Twenty-seven individuals underwent an exercise test in the supine position on a bicycle ergometer. The initial workload was 30 Watts, followed by 20-Watt increments every third minute. Standard echocardiographic images with super-imposed colour TDE were digitized at the end of each step. The following variables were studied in the LV long- and short-axis: myocardial peak systolic velocity (PSV) and excursion, isovolumic contraction and relaxation times, peak velocity at early diastole (E-wave) and peak velocity at late diastole (A'-wave) and the E'/A' ratio. Increments in myocardial peak systolic velocity and excursion in the LV long-axis were more pronounced during low workloads. The increase in those variables in the short-axis occurred mainly, at higher exercise loads. The improvement in LV long- and short-axis functions was closely related to the increase in the heart rate. Shortening of the isovolumic contraction and relaxation times occurred only at the initial stages of exercise. An increase in the long-axis E'/A' ratio occurred during exercise, whereas this ratio was unchanged in the short-axis. In conclusion, during exercise, the LV long- and short-axis functions behave differently, and increases in LV long- and short-axis functions are related to changes in heart rate. Therefore, in the interpretation of echocardiographic findings during exercise stress echocardiography, these facts have to be taken into account.
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| 10. |
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| 11. |
- Quintana, M., et al.
(författare)
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Electromechanical coupling, uncoupling, and ventricular function in patients with bundle branch block : A tissue-doppler echocardiographic study
- 2004
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Ingår i: Echocardiography. - : Wiley. - 0742-2822 .- 1540-8175. ; 21:8, s. 687-698
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Tidskriftsartikel (refereegranskat)abstract
- Background: Left bundle branch block (LBBB) is associated with impaired left ventricular (LV) function and increased morbidity and mortality, especially in patients with structural heart diseases. The mechanisms are poorly understood. Subjects and Methods: Subjects with isolated LBBB (n = 20), right bundle branch block (RBBB, n = 20), and controls (C, n = 20) were studied with standard two-dimentional (2D), and color-encoded tissue-Doppler echocardiography (TDE). Inter- and intraventricular systolic and diastolic coordination were assessed from the TDE velocity profiles. LV function was assessed by 2D echocardiography, by TDE-derived peak systolic velocities, and the atrioventricular (AV) plane displacement. Results: Subjects with LBBB had longer electromechanical delays and longer isovolumic relaxation times than did the C and RBBB groups (P < 0.001). For the LBBB subjects compared with the RBBB and C groups, ejection times were shorter, peak systolic velocities and AV plane displacements were lower, they had larger LV end-systolic volumes and lower LV ejection fraction (all P < 0.001), and the atrial contribution to A-V plane displacement was higher (P < 0.01). There were no differences in diastolic or filling times among the groups. Conclusions: In patients with LBBB, delayed regional electromechanical coupling and uncoupling leads to generalized intra- and interventricular asynchrony, thereby explaining the depressed regional and global LV functions. Assessment of the electromechanical coupling and uncoupling processes and their consequences on cardiac function in patients with BBB and structural heart diseases may be possible using TDE.
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| 12. |
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| 13. |
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| 14. |
- Walhovd, Kristine B., et al.
(författare)
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Neurodevelopmental origins of lifespan changes in brain and cognition
- 2016
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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. ; 113:33, s. 9357-9362
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Tidskriftsartikel (refereegranskat)abstract
- Neurodevelopmental origins of functional variation in older age are increasingly being acknowledged, but identification of how early factors impact human brain and cognition throughout life has remained challenging. Much focus has been on age-specific mechanisms affecting neural foundations of cognition and their change. In contrast to this approach, we tested whether cerebral correlates of general cognitive ability (GCA) in development could be extended to the rest of the lifespan, and whether early factors traceable to prenatal stages, such as birth weight and parental education, may exert continuous influences. We measured the area of the cerebral cortex in a longitudinal sample of 974 individuals aged 4-88 y (1,633 observations). An extensive cortical region was identified wherein area related positively to GCA in development. By tracking area of the cortical region identified in the child sample throughout the lifespan, we showed that the cortical change trajectories of higher and lower GCA groups were parallel through life, suggesting continued influences of early life factors. Birth weight and parental education obtained from the Norwegian Mother-Child Cohort study were identified as such early factors of possible lifelong influence. Support for a genetic component was obtained in a separate twin sample (Vietnam Era Twin Study of Aging), but birth weight in the child sample had an effect on cortical area also when controlling for possible genetic differences in terms of parental height. Our results provide novel evidence for stability in brain-cognition relationships throughout life, and indicate that early life factors impact brain and cognition for the entire life course.
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| 15. |
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| 16. |
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| 17. |
- Enghag, Sara, et al.
(författare)
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Incus Necrosis and Blood Supply : A Micro-CT and Synchrotron Imaging Study
- 2019
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Ingår i: Otology and Neurotology. - : LIPPINCOTT WILLIAMS & WILKINS. - 1531-7129 .- 1537-4505. ; 40:7, s. E713-E722
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Tidskriftsartikel (refereegranskat)abstract
- Background: Incus necrosis is a common complication following stapes surgery and is associated with impaired microcirculation. The objective of this study was to investigate the vascular anatomy of the human incus by using light microscopy, micro-computed tomography (micro-CT), and synchrotron phase-contrast imaging (SR-PCI) for a novel three-dimensional (3D) analysis of the middle ear, mucosal folds, major vascular pathways, and intraosseous vascular bone channels. Methods: One-hundred-and-fifty temporal bones from the Uppsala collection were analyzed under light microscopy. Twenty temporal bones underwent high-resolution micro-CT scanning, and an additional seven specimens underwent SR-PCI at the Canadian Lightsource in Saskatoon, Canada. One of these specimens was from an individual who had undergone stapes surgery. Data were processed with volume-rendering software to create 3D reconstructions using scalar opacity mapping for bone transparency, cropping, and soft tissue analyses. Results: Micro-CT and SR-PCI with 3D rendering revealed the extensive vascular plexus within the un-decalcified incus bone communicating with the exterior surface. The relationship between the vessels, lenticular process, and incudostape-dial joint were clearly observed. SR-PCI allowed for histologic-level detail while preserving the specimen and its 3D relationships. Conclusion: SR-PCI with 3D reconstructions confirmed the main vascular supply to the lenticular process along the intraosseous lenticular vessels. This is the first synchrotron analysis of a patient having undergone stapes surgery, and it suggests that incus necrosis associated with stapes surgery may be caused by a disruption of the lenticular blood flow induced by the prosthesis loop, and not by strangulation of mucosal vessels as has been previously described.
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| 18. |
- Ghanavatian, S, et al.
(författare)
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Subclinical atherosclerosis, endothelial function, and serum inflammatory markers in chronic kidney disease stages 3 to 4
- 2014
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Ingår i: Angiology. - : SAGE Publications. - 1940-1574 .- 0003-3197. ; 65:5, s. 443-449
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Tidskriftsartikel (refereegranskat)abstract
- Different inflammatory markers, brachial artery flow-mediated dilatation (FMD), and brachial intima-media thickness (bIMT) were measured in 50 patients with chronic kidney disease (CKD) stages 3 to 4 with estimated glomerular filtration rate (eGFR) and 35 age- and gender-matched controls. The bIMT was significantly increased in the patients with CKD compared with controls (0.43 mm [0.42, 0.45] vs 0.34 mm [0.32, 0.36]; P < .001). There was no significant difference in FMD between the study groups (4.7% vs 5.3%; P = .56). There were significant correlations between bIMT and high-sensitive C-reactive protein, vascular cellular adhesion molecule 1, tumor necrosis factor, and interleukin 6 ( P < .05). However, eGFR adjusted for age and gender was the best predictor of bIMT. In conclusion, bIMT and inflammatory markers were increased in patients with CKD compared with the controls. Furthermore, significant correlations between bIMT and inflammatory activity in patients with CKD were observed. The eGFR adjusted for age and gender was the best predictor of bIMT.
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| 19. |
- Glasø de Lange, Ann-Marie, et al.
(författare)
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White matter integrity as a marker for cognitive plasticity in aging
- 2016
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 47, s. 74-82
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Tidskriftsartikel (refereegranskat)abstract
- Age-related differences in white matter (WM) integrity are substantial, but it is unknown whether between subject variability in WM integrity influences the capacity for cognitive improvement. We investigated the effects of memory training related to active and passive control conditions in older adults and tested whether WM integrity at baseline was predictive of training benefits. We hypothesized that (1) memory improvement would be restricted to the training group, (2) widespread areas would show greater mean diffusivity (MD) and lower fractional anisotropy in older adults relative to young adults, and (3) within these areas, variability in WM microstructure in the older group would be predictive of training gains. The results showed that only the group receiving training improved their memory. Significant age differences in MD and fractional anisotropy were found in widespread areas. Within these areas, voxelwise analyses showed a negative relationship between MD and memory improvement in 3 clusters, indicating that WM integrity could serve as a marker for the ability to adapt in response to cognitive challenges in aging.
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| 20. |
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| 21. |
- Helpard, Luke, et al.
(författare)
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An Approach for Individualized Cochlear Frequency Mapping Determined From 3D Synchrotron Radiation Phase-Contrast Imaging
- 2021
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Ingår i: IEEE Transactions on Biomedical Engineering. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9294 .- 1558-2531. ; 68:12, s. 3602-3611
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Cochlear implants are traditionally programmed to stimulate according to a generalized frequency map, where individual anatomic variability is not considered when selecting the centre frequency of stimulation of each implant electrode. However, high variability in cochlear size and spatial frequency distributions exist among individuals. Generalized cochlear implant frequency maps can result in large pitch perception errors and reduced hearing outcomes for cochlear implant recipients. The objective of this work was to develop an individualized frequency mapping technique for the human cochlea to allow for patient-specific cochlear implant stimulation.Methods: Ten cadaveric human cochleae were scanned using synchrotron radiation phase-contrast imaging (SR-PCI) combined with computed tomography (CT). For each cochlea, ground truth angle-frequency measurements were obtained in three-dimensions using the SR-PCI CT data. Using an approach designed to minimize perceptual error in frequency estimation, an individualized frequency function was determined to relate angular depth to frequency within the cochlea.Results: The individualized frequency mapping function significantly reduced pitch errors in comparison to the current gold standard generalized approach.Conclusion and Significance: This paper presents for the first time a cochlear frequency map which can be individualized using only the angular length of cochleae. This approach can be applied in the clinical setting and has the potential to revolutionize cochlear implant programming for patients worldwide.
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| 22. |
- Helpard, Luke, et al.
(författare)
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Three-Dimensional Modeling and Measurement of the Human Cochlear Hook Region : Considerations for Tonotopic Mapping
- 2021
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Ingår i: Otology and Neurotology. - : Lippincott Williams & Wilkins. - 1531-7129 .- 1537-4505. ; 42:6, s. E658-E665
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Tidskriftsartikel (refereegranskat)abstract
- Hypothesis: Measuring the length of the basilar membrane (BM) in the cochlear hook region will result in improved accuracy of cochlear duct length (CDL) measurements.Background: Cochlear implant pitch mapping is generally performed in a patient independent approach, which has been shown to result in place-pitch mismatches. In order to customize cochlear implant pitch maps, accurate CDL measurements must be obtained. CDL measurements generally begin at the center of the round window (RW) and ignore the basal-most portion of the BM in the hook region. Measuring the size and morphology of the BM in the hook region can improve CDL measurements and our understanding of cochlear tonotopy.Methods: Ten cadaveric human cochleae underwent synchrotron radiation phase-contrast imaging. The length of the BM through the hook region and CDL were measured. Two different CDL measurements were obtained for each sample, with starting points at the center of the RW (CDLRW) and the basal-most tip of the BM (CDLHR). Regression analysis was performed to relate CDLRW to CDLHR. A three-dimensional polynomial model was determined to describe the average BM hook region morphology.Results: The mean CDLRW value was 33.03 ± 1.62 mm, and the mean CDLHR value was 34.68 ± 1.72 mm. The following relationship was determined between CDLRW and CDLHR: CDLHR = 1.06(CDLRW)-0.26 (R2 = 0.99).Conclusion: The length and morphology of the hook region was determined. Current measurements underestimate CDL in the hook region and can be corrected using the results herein.
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| 23. |
- Jones, Benjamin L. H., et al.
(författare)
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Dependence on seagrass fisheries governed by household income and adaptive capacity
- 2022
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Ingår i: Ocean and Coastal Management. - : Elsevier BV. - 0964-5691 .- 1873-524X. ; 225
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Tidskriftsartikel (refereegranskat)abstract
- Seagrass meadows, like other tropical coastal ecosystems, are highly productive and sustain millions of people worldwide. However, the factors that govern the use of seagrass as a fishing habitat over other habitats are largely unknown, especially at the household scale. Using socioeconomic factors from 147 villages across four countries within the Indo-Pacific, we examined the drivers of household dependence on seagrass. We revealed that seagrass was the most common habitat used for fishing across villages in all the countries studied, being preferred over other habitats for reliability. Using structural equation modelling, we exposed how household income and adaptive capacity appears to govern dependence on seagrass. Poorer households were less likely to own motorboats and dependent on seagrass as they were unable to fish elsewhere, whereas wealthier households were more likely to invest in certain fishing gears that incentivised them to use seagrass habitats due to high rewards and low effort requirements. Our findings accentuate the complexity of seagrass social-ecological systems and the need for empirical household scale data for effective management. Safeguarding seagrass is vital to ensure that vulnerable households have equitable and equal access to the resource, addressing ocean recovery and ensuring sustainable coastal communities.
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| 24. |
- Jones, Benjamin L., et al.
(författare)
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Local Ecological Knowledge Reveals Change in Seagrass Social–Ecological Systems
- 2022
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Ingår i: Oceans. - : MDPI AG. - 2673-1924. ; 3:3, s. 419-430
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Tidskriftsartikel (refereegranskat)abstract
- It is widely recognized that humanity is currently facing multiple planetary crises, including the widespread loss of biodiversity and a rapidly changing climate. The impacts of these crises are often far reaching and threaten food security (SDG goal two: zero hunger). Small-scale fisheries are estimated to provide livelihoods for over one hundred million people and sustenance for approximately one billion people but face a plethora of threats and challenges linked to planetary crises. In this multi-country assessment (150 coastal villages across five countries within the Indo-Pacific), household interviews revealed how seagrass meadows are important to small-scale fisheries, particularly as a place to find and collect a reliable source of food. Interviews also revealed that habitat loss and the over-exploitation of these resources are placing people and their food security at risk. This study exposed how dynamic local ecological knowledge can be, uncovering personal opinions and responsibilities that result in the hybridization of knowledge. Here, we demonstrate the importance of using local ecological knowledge to incorporate shared values into management but also highlight that an integrated approach, pairing local and conventional scientific knowledge, is needed urgently if we are to meet the needs of people while simultaneously conserving biodiversity.
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| 25. |
- Li, Hao, 1984-, et al.
(författare)
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A Synchrotron and Micro-CT Study of the Human Endolymphatic Duct System : Is Meniere's Disease Caused by an Acute Endolymph Backflow?
- 2021
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Ingår i: Frontiers in Surgery. - : Frontiers Media S.A.. - 2296-875X. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Background: The etiology of Meniere's disease (MD) and endolymphatic hydrops believed to underlie its symptoms remain unknown. One reason may be the exceptional complexity of the human inner ear, its vulnerability, and surrounding hard bone. The vestibular organ contains an endolymphatic duct system (EDS) bridging the different fluid reservoirs. It may be essential for monitoring hydraulic equilibrium, and a dysregulation may result in distension of the fluid spaces or endolymphatic hydrops. Material and Methods: We studied the EDS using high-resolution synchrotron phase contrast non-invasive imaging (SR-PCI), and micro-computed tomography (micro-CT). Ten fresh human temporal bones underwent SR-PCI. One bone underwent micro-CT after fixation and staining with Lugol's iodine solution (I2KI) to increase tissue resolution. Data were processed using volume-rendering software to create 3D reconstructions allowing orthogonal sectioning, cropping, and tissue segmentation. Results: Combined imaging techniques with segmentation and tissue modeling demonstrated the 3D anatomy of the human saccule, utricle, endolymphatic duct, and sac together with connecting pathways. The utricular duct (UD) and utriculo-endolymphatic valve (UEV or Bast's valve) were demonstrated three-dimensionally for the first time. The reunion duct was displayed with micro-CT. It may serve as a safety valve to maintain cochlear endolymph homeostasis under certain conditions. Discussion: The thin reunion duct seems to play a minor role in the exchange of endolymph between the cochlea and vestibule under normal conditions. The saccule wall appears highly flexible, which may explain occult hydrops occasionally preceding symptoms in MD on magnetic resonance imaging (MRI). The design of the UEV and connecting ducts suggests that there is a reciprocal exchange of fluid among the utricle, semicircular canals, and the EDS. Based on the anatomic framework and previous experimental data, we speculate that precipitous vestibular symptoms in MD arise from a sudden increase in endolymph pressure caused by an uncontrolled endolymphatic sac secretion. A rapid rise in UD pressure, mediated along the fairly wide UEV, may underlie the acute vertigo attack, refuting the rupture/K+-intoxication theory.
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| 26. |
- Li, Hao, 1984-, et al.
(författare)
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Aeration of the Human Prussak's Space : A 3D Synchrotron Imaging Study
- 2021
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Ingår i: Otology and Neurotology. - : Lippincott Williams & Wilkins. - 1531-7129 .- 1537-4505. ; 42:7, s. E894-E904
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Prussak's space (PS) is an intricate middle ear region which may play an essential role in the development of middle ear disease. The three-dimensional (3D) anatomy of the human PS and its drainage routes remain relatively unknown. Earlier studies have histologically analyzed PS, by micro-dissection and endoscopy. Here, we used synchrotron-radiation phase-contrast imaging (SR-PCI), 3D reconstructions, and modeling to study the framework of the human PS, including aeration pathways. It may lead to increased understanding of development of middle ear pathology.Design: Nine human temporal bone specimens underwent in-line SR-PCI at the Canadian Light Source in Saskatoon, Saskatchewan, Canada. Data were processed with volume-rendering software to create 3D reconstructions using scalar opacity mapping and segmentations to visualize its walls in fixed, undecalcified human temporal bones.Results: The PS was found to be an irregular, variably shaped chamber with different aeration systems. Three different drainage pathways were found: 1) via the posterior malleolar pouch of von Troltsch in seven of nine ears; 2) directly posterior-inferior into the mesotympanum medial to the posterior malleolar pouch in one ear; and 3) anteriorly in another. The posterior-inferior communications depended on the anatomy of the posterior malleolar fold. In one bilateral case, the aeration differed between the ears. Earlier descriptions of upper ventilation routes between the PS and the epitympanic spaces could not be substantiated.Conclusions: The 3D anatomy of the membrane folds organizing the PS in humans was demonstrated for the first time using in-line SR-PCI. The PS was always aerated into the mesotympanum, suggesting its relative independence of attic ventilation. The impact of its various drainage routes on middle ear ventilation and disease were discussed.
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| 27. |
- Li, Hao, 1984-, et al.
(författare)
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Synchrotron Radiation-Based Reconstruction of the Human Spiral Ganglion : Implications for Cochlear Implantation
- 2020
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Ingår i: Ear and Hearing. - : LIPPINCOTT WILLIAMS & WILKINS. - 0196-0202 .- 1538-4667. ; 41:1, s. 173-181
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To three-dimensionally reconstruct Rosenthal's canal (RC) housing the human spiral ganglion (SG) using synchrotron radiation phase-contrast imaging (SR-PCI). Straight cochlear implant electrode arrays were inserted to better comprehend the electro-cochlear interface in cochlear implantation (CI).Design: SR-PCI was used to reconstruct the human cochlea with and without cadaveric CI. Twenty-eight cochleae were volume rendered, of which 12 underwent cadaveric CI with a straight electrode via the round window (RW). Data were input into the 3D Slicer software program and anatomical structures were modeled using a threshold paint tool.Results: The human RC and SG were reproduced three-dimensionally with artefact-free imaging of electrode arrays. The anatomy of the SG and its relationship to the sensory organ (Corti) and soft and bony structures were assessed.Conclusions: SR-PCI and computer-based three-dimensional reconstructions demonstrated the relationships among implanted electrodes, angular insertion depths, and the SG for the first time in intact, unstained, and nondecalcified specimens. This information can be used to assess stimulation strategies and future electrode designs, as well as create place-frequency maps of the SG for optimal stimulation strategies of the human auditory nerve in CI.
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| 28. |
- Li, Hao, 1984-, et al.
(författare)
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Three-dimensional tonotopic mapping of the human cochlea based on synchrotron radiation phase-contrast imaging
- 2021
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- The human cochlea transforms sound waves into electrical signals in the acoustic nerve fibers with high acuity. This transformation occurs via vibrating anisotropic membranes (basilar and tectorial membranes) and frequency-specific hair cell receptors. Frequency-positions can be mapped within the cochlea to create a tonotopic chart which fits an almost-exponential function with lowest frequencies positioned apically and highest frequencies positioned at the cochlear base (Bekesy 1960, Greenwood 1961). To date, models of frequency positions have been based on a two-dimensional analysis with inaccurate representations of the cochlear hook region. In the present study, the first three-dimensional frequency analysis of the cochlea using dendritic mapping to obtain accurate tonotopic maps of the human basilar membrane/organ of Corti and the spiral ganglion was performed. A novel imaging technique, synchrotron radiation phase-contrast imaging, was used and a spiral ganglion frequency function was estimated by nonlinear least squares fitting a Greenwood-like function (F=A (10(ax) - K)) to the data. The three-dimensional tonotopic data presented herein has large implications for validating electrode position and creating customized frequency maps for cochlear implant recipients.
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| 29. |
- Li, Hao, 1984-, et al.
(författare)
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Vestibular Organ and Cochlear Implantation-A Synchrotron and Micro-CT Study
- 2021
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Ingår i: Frontiers in Neurology. - : Frontiers Media S.A.. - 1664-2295. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Background: Reports vary on the incidence of vestibular dysfunction and dizziness in patients following cochlear implantation (CI). Disequilibrium may be caused by surgery at the cochlear base, leading to functional disturbances of the vestibular receptors and endolymphatic duct system (EDS) which are located nearby. Here, we analyzed the three-dimensional (3D) anatomy of this region, aiming to optimize surgical approaches to limit damage to the vestibular organ.Material and Methods: A total of 22 fresh-frozen human temporal bones underwent synchrotron radiation phase-contrast imaging (SR-PCI). One temporal bone underwent micro-computed tomography (micro-CT) after fixation and staining with Lugol's iodine solution (I2KI) to increase tissue contrast. We used volume-rendering software to create 3D reconstructions and tissue segmentation that allowed precise assessment of anatomical relationships and topography. Macerated human ears belonging to the Uppsala collection were also used. Drilling and insertion of CI electrodes was performed with metric analyses of different trajectories.Results and Conclusions: SR-PCI and micro-CT imaging demonstrated the complex 3D anatomy of the basal region of the human cochlea, vestibular apparatus, and EDS. Drilling of a cochleostomy may disturb vestibular organ function by injuring the endolymphatic space and disrupting fluid barriers. The saccule is at particular risk due to its proximity to the surgical area and may explain immediate and long-term post-operative vertigo. Round window insertion may be less traumatic to the inner ear, however it may affect the vestibular receptors.
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