54 resultados para fracture and deformation concepts
Resumo:
The study of semantic memory in patients with Alzheimer's disease (AD) has raised important questions about the representation of conceptual knowledge in the human brain. It is still unknown whether semantic memory impairments are caused by localized damage to specialized regions or by diffuse damage to distributed representations within nonspecialized brain areas. To our knowledge, there have been no direct correlations of neuroimaging of in vivo brain function in AD with performance on tasks differentially addressing visual and functional knowledge of living and nonliving concepts. We used a semantic verification task and resting 18-fluorodeoxyglucose positron emission tomography in a group of mild to moderate AD patients to investigate this issue. The four task conditions required semantic knowledge of (1) visual, (2) functional properties of living objects, and (3) visual or (4) functional properties of nonliving objects. Visual property verification of living objects was significantly correlated with left posterior fusiform gyrus metabolism (Brodmann's area [BA] 37/19). Effects of visual and functional property verification for non-living objects largely overlapped in the left anterior temporal (BA 38/20) and bilateral premotor areas (BA 6), with the visual condition extending more into left lateral precentral areas. There were no associations with functional property verification for living concepts. Our results provide strong support for anatomically separable representations of living and nonliving concepts, as well as visual feature knowledge of living objects, and against distributed accounts of semantic memory that view visual and functional features of living and nonliving objects as distributed across a common set of brain areas.
Resumo:
BACKGROUND: Severe brain trauma leads to an activation of the immune system. To this date, neither the exact perturbation of the specific immune reaction induced by the traumatic brain injury (TBI), nor the interactions leading to the infiltration of peripheral immune cells into the brain are fully understood. PATIENTS AND METHODS: Serum was collected from 17 patients with TBI and a long bone fracture, 24 patients with an isolated long bone fracture and from healthy individuals. The effect of the serum on normal human monocytes and T-lymphocytes was tested in vitro by assessing proliferation and expression of surface markers, chemokine receptors and cytokines. RESULTS: Serum collected from patients with a TBI and a long bone fracture increased the expression of the chemokine receptor CCR4 in monocytes when compared to patients with an isolated long bone fracture. Extending this comparison to T-lymphocytes, the serum from TBI patients induced lower proliferation rates and decreased expression of the pro-inflammatory cytokine TNF-alpha, while simultaneously increasing the secretion of immune-modulatory cytokines (IL-4, IL-10 and TGF-beta) (p<0.05). CONCLUSION: Patients with a TBI release currently unknown soluble factors into the circulating blood that up regulate expression of chemokine receptor CCR4 in peripheral blood monocytes whilst concurrently inducing expression of immunosuppressive cytokines by activated T-lymphocytes.
Resumo:
The authors describe a case of sellar fracture followed by sudden death. The victim was involved in a wrangle. The autopsy revealed facial damage and sellar fracture and no evidence of cerebral damage, except for a mild subarachnoid hemorrhage in the left parietotemporal regions and undersurface of both frontal lobes. Sellar fracture is a rare and severe entity, associated with serious complications, which is frequently diagnosed postmortem. In any case, death is rarely a direct consequence of the sellar fracture itself and is usually considered to be the result of associated cerebral trauma. This case prompted us to screen the literature on sellar fracture to gain a better understanding of the mechanism of death.
Resumo:
In variational linguistics, the concept of space has always been a central issue. However, different research traditions considering space coexisted for a long time separately. Traditional dialectology focused primarily on the diatopic dimension of linguistic variation, whereas in sociolinguistic studies diastratic and diaphasic dimensions were considered. For a long time only very few linguistic investigations tried to combine both research traditions in a two-dimensional design – a desideratum which is meant to be compensated by the contributions of this volume. The articles present findings from empirical studies which take on these different concepts and examine how they relate to one another. Besides dialectological and sociolinguistic concepts also a lay perspective of linguistic space is considered, a paradigm that is often referred to as “folk dialectology”. Many of the studies in this volume make use of new computational possibilities of processing and cartographically representing large corpora of linguistic data. The empirical studies incorporate findings from different linguistic communities in Europe and pursue the objective to shed light on the inter-relationship between the different concepts of space and their relevance to variational linguistics.
Resumo:
The paper deals with the development of a general as well as integrative and holistic framework to systematize and assess vulnerability, risk and adaptation. The framework is a thinking tool meant as a heuristic that outlines key factors and different dimensions that need to be addressed when assessing vulnerability in the context of natural hazards and climate change. The approach underlines that the key factors of such a common framework are related to the exposure of a society or system to a hazard or stressor, the susceptibility of the system or community exposed, and its resilience and adaptive capacity. Additionally, it underlines the necessity to consider key factors and multiple thematic dimensions when assessing vulnerability in the context of natural and socio-natural hazards. In this regard, it shows key linkages between the different concepts used within the disaster risk management (DRM) and climate change adaptation (CCA) research. Further, it helps to illustrate the strong relationships between different concepts used in DRM and CCA. The framework is also a tool for communicating complexity and stresses the need for societal change in order to reduce risk and to promote adaptation. With regard to this, the policy relevance of the framework and first results of its application are outlined. Overall, the framework presented enhances the discussion on how to frame and link vulnerability, disaster risk, risk management and adaptation concepts.
Resumo:
Data on treatment of glucocorticoid-induced osteoporosis (GIO) in men are scarce. We performed a randomized, open-label trial in men who have taken glucocorticoids (GC) for ≥3 months, and had an areal bone mineral density (aBMD) T-score ≤ –1.5 standard deviations. Subjects received 20 μg/d teriparatide (n = 45) or 35 mg/week risedronate (n = 47) for 18 months. Primary objective was to compare lumbar spine (L1–L3) BMD measured by quantitative computed tomography (QCT). Secondary outcomes included BMD and microstructure measured by high-resolution QCT (HRQCT) at the 12th thoracic vertebra, biomechanical effects for axial compression, anterior bending, and axial torsion evaluated by finite element (FE) analysis from HRQCT data, aBMD by dual X-ray absorptiometry, biochemical markers, and safety. Computed tomography scans were performed at 0, 6, and 18 months. A mixed model repeated measures analysis was performed to compare changes from baseline between groups. Mean age was 56.3 years. Median GC dose and duration were 8.8 mg/d and 6.4 years, respectively; 39.1% of subjects had a prevalent fracture, and 32.6% received prior bisphosphonate treatment. At 18 months, trabecular BMD had significantly increased for both treatments, with significantly greater increases with teriparatide (16.3% versus 3.8%; p = 0.004). HRQCT trabecular and cortical variables significantly increased for both treatments with significantly larger improvements for teriparatide for integral and trabecular BMD and bone surface to volume ratio (BS/BV) as a microstructural measure. Vertebral strength increases at 18 months were significant in both groups (teriparatide: 26.0% to 34.0%; risedronate: 4.2% to 6.7%), with significantly higher increases in the teriparatide group for all loading modes (0.005 < p < 0.015). Adverse events were similar between groups. None of the patients on teriparatide but five (10.6%) on risedronate developed new clinical fractures (p = 0.056). In conclusion, in this 18-month trial in men with GIO, teriparatide showed larger improvements in spinal BMD, microstructure, and FE-derived strength than risedronate.
Resumo:
Life expectancy continuously increases but our society faces age-related conditions. Among musculoskeletal diseases, osteoporosis associated with risk of vertebral fracture and degenerative intervertebral disc (IVD) are painful pathologies responsible for tremendous healthcare costs. Hence, reliable diagnostic tools are necessary to plan a treatment or follow up its efficacy. Yet, radiographic and MRI techniques, respectively clinical standards for evaluation of bone strength and IVD degeneration, are unspecific and not objective. Increasingly used in biomedical engineering, CT-based finite element (FE) models constitute the state-of-art for vertebral strength prediction. However, as non-invasive biomechanical evaluation and personalised FE models of the IVD are not available, rigid boundary conditions (BCs) are applied on the FE models to avoid uncertainties of disc degeneration that might bias the predictions. Moreover, considering the impact of low back pain, the biomechanical status of the IVD is needed as a criterion for early disc degeneration. Thus, the first FE study focuses on two rigid BCs applied on the vertebral bodies during compression test of cadaver vertebral bodies, vertebral sections and PMMA embedding. The second FE study highlights the large influence of the intervertebral disc’s compliance on the vertebral strength, damage distribution and its initiation. The third study introduces a new protocol for normalisation of the IVD stiffness in compression, torsion and bending using MRI-based data to account for its morphology. In the last study, a new criterion (Otsu threshold) for disc degeneration based on quantitative MRI data (axial T2 map) is proposed. The results show that vertebral strength and damage distribution computed with rigid BCs are identical. Yet, large discrepancies in strength and damage localisation were observed when the vertebral bodies were loaded via IVDs. The normalisation protocol attenuated the effect of geometry on the IVD stiffnesses without complete suppression. Finally, the Otsu threshold computed in the posterior part of annulus fibrosus was related to the disc biomechanics and meet objectivity and simplicity required for a clinical application. In conclusion, the stiffness normalisation protocol necessary for consistent IVD comparisons and the relation found between degeneration, mechanical response of the IVD and Otsu threshold lead the way for non-invasive evaluation biomechanical status of the IVD. As the FE prediction of vertebral strength is largely influenced by the IVD conditions, this data could also improve the future FE models of osteoporotic vertebra.
Resumo:
This Strategy and Action Plan was written within the framework of the project on Sustainable Land Management in the High Pamir and Pamir-Alai Mountains (PALM). PALM is an integrated transboundary initiative of the governments of the Kyrgyz Republic and the Republic of Tajikistan. It aims to address the interlinked problems of land degradation and poverty within a region that is one of Central Asia’s crucial sources of freshwater and a location of biodiversity hotspots. The project is executed by the Committee on Environment Protection in Tajikistan and the National Center for Mountain Regions Development in Kyrgyzstan, with fi nancial support from the Global Environment Facility (GEF) and other donors. The United Nations Environment Programme (UNEP) is the GEF Implementing Agency for the project, and the United Nations University (UNU) is the International Executing Agency. This Strategy and Action Plan integrates the work of three main teams of experts, namely the Pamir-Alai Transboundary Strategy and Action Plan (PATSAP) team, the Legal Task Forces, and a team of Natural Disaster Risk specialists. The PATSAP team was coordinated by the Centre for Development and Environment (CDE), University of Bern, Switzerland. The Legal Task Force was led by the Australian Centre for Agriculture and Law of the University of New England (UNE), and responsibility for the Natural Disaster Risk assessment was with the Central- Asian Institute of Applied Geosciences (CAIAG) in Bishkek, Kyrgyzstan. The development of the strategy took place from June 2009 to October 2010. The activities included fi eld study tours for updating the information base with fi rst-hand information from the local level, coordination meetings with actors from the region, and two multi-level stakeholder forums conducted in Khorog and Osh to identify priorities and to collect ideas for concrete action plans. The baseline information collected for the Strategy and Action Plan has been compiled by the experts and made available as reports1. A joint multi-level stakeholder forum was conducted in Jirgitol, Tajikistan, for in-depth discussion of the transboundary aspects. In August 2010, the draft Strategy and Action Plan was distributed among local, national, and international actors for consultation, and their comments were discussed at feedback forums in Khorog and Bishkek. This Strategy and Action Plan is intended as a recommendation. Nevertheless, it proposes concrete mechanisms for implementing the proposed sustainable land management (SLM) activities: The Regional Natural Resources Governance Framework provides the legal and policy concepts, principles, and regulatory requirements needed to create an enabling environment for SLM in the High Pamir and Pamir-Alai region at the transboundary, national, and local levels. The priority directions outlined provide a framework for the elaboration of rayon-level strategies and for strategies on specifi c topics (forestry, livestock, etc.), as well as for further development of government programmes and international projects. The action plans may serve as a pool of concrete ideas, which can be taken up by diff erent institutions and in smaller or larger projects. Finally, this document provides a basis for the elaboration and signing of targeted cooperation agreements on land use and management between the leaders of Osh oblast (Kyrgyz Republic), Gorno Badakhshan Autonomous Oblast, and Jirgitol rayon (Republic of Tajikistan).
Resumo:
Land systems are the result of human interactions with the natural environment. Understanding the drivers, state, trends and impacts of different land systems on social and natural processes helps to reveal how changes in the land system affect the functioning of the socio-ecological system as a whole and the tradeoff these changes may represent. The Global Land Project has led advances by synthesizing land systems research across different scales and providing concepts to further understand the feedbacks between social-and environmental systems, between urban and rural environments and between distant world regions. Land system science has moved from a focus on observation of change and understanding the drivers of these changes to a focus on using this understanding to design sustainable transformations through stakeholder engagement and through the concept of land governance. As land use can be seen as the largest geo-engineering project in which mankind has engaged, land system science can act as a platform for integration of insights from different disciplines and for translation of knowledge into action.
Resumo:
Benign bone lesions in children although rare, can result in a pathological fracture. Although their etiology and pathogenesis are not yet entirely clear, the phenomenon of spontaneous healing is well known. Nevertheless, some benign bone lesions are unlikely to heal spontaneously due to the patient's age or high risk of fracture and deformity due to the lesion's location or size. The following study presents our results after treatment of these bone cysts with chronOS Inject.