214 research outputs found
Сім сліз Івана Чендея
Розглядається творчість Івана Чендея на рівні структурних та функціональних особливостей символічних образів сльози, уточнюються оцінки окремих творів з погляду їхньої взаємодії з часом
Journal Staff
Purpose: To investigate the accuracy of wall shear stress (WSS) estimation using MRI. Specifically, to investigate the impact of different parameters and if MRI WSS estimates are monotonically related to actual WSS. Materials and Methods: The accuracy of WSS estimation using methods based on phase-contrast (PC) MRI velocity mapping, Fourier velocity encoding (FVE) and intravoxel velocity standard deviation mapping were studied using numerical simulations. The influence of spatial resolution, velocity encoding, wall segmentation, and voxel location were investigated over a range of WSS values. Results: WSS estimates were found to be sensitive to parameter settings in general and spatial resolution in particular. All methods underestimated WSS, except for the FVE-based method, which instead was extremely sensitive to voxel position relative to the wall. Methods using PC-based WSS estimation with wall segmentation showed to be accurate for low WSS, but were sensitive to segmentation errors. Conclusion: Even in the absence of noise and for relatively simple velocity profiles, MRI WSS estimates cannot always be assumed to be linearly or even monotonically related to actual WSS. High WSS values cannot be resolved and the estimates depend on parameter setting. Nevertheless, distinguishing areas of low and moderate WSS may be feasible
Segmental variation of myocardial deformation in patients with suspected ischemic heart disease
Faster 3D cardiac CT segmentation with Vision Transformers
Accurate segmentation of the heart is essential for personalized blood flow
simulations and surgical intervention planning. A recent advancement in image
recognition is the Vision Transformer (ViT), which expands the field of view to
encompass a greater portion of the global image context. We adapted ViT for
three-dimensional volume inputs. Cardiac computed tomography (CT) volumes from
39 patients, featuring up to 20 timepoints representing the complete cardiac
cycle, were utilized. Our network incorporates a modified ResNet50 block as
well as a ViT block and employs cascade upsampling with skip connections.
Despite its increased model complexity, our hybrid Transformer-Residual U-Net
framework, termed TRUNet, converges in significantly less time than residual
U-Net while providing comparable or superior segmentations of the left
ventricle, left atrium, left atrial appendage, ascending aorta, and pulmonary
veins. TRUNet offers more precise vessel boundary segmentation and better
captures the heart's overall anatomical structure compared to residual U-Net,
as confirmed by the absence of extraneous clusters of missegmented voxels. In
terms of both performance and training speed, TRUNet exceeded U-Net, a commonly
used segmentation architecture, making it a promising tool for 3D semantic
segmentation tasks in medical imaging. The code for TRUNet is available at
github.com/ljollans/TRUNet
Myocardial mapping of T1 and T2 with 3D-QALAS - precision of independent and dependent scans in healthy subjects
Fibromodulin Interacts with Collagen Cross-linking Sites and Activates Lysyl Oxidase
The hallmark of fibrotic disorders is a highly cross-linked and dense collagen matrix, a property driven by the oxidative action of lysyl oxidase. Other fibrosis-associated proteins also contribute to the final collagen matrix properties, one of which is fibromodulin - its interactions with collagen affect collagen cross-linking, packing, and fibril diameter. We investigated the possibility that a specific relationship exists between fibromodulin and lysyl oxidase, potentially imparting a specific collagen matrix phenotype. We mapped the fibromodulin-collagen interaction sites using the Collagen II and III Toolkit peptide libraries. Fibromodulin interacted with the peptides containing the known collagen cross-linking sites and the MMP-1 cleavage site in collagens I and II. Interestingly, the interaction sites are closely aligned within the quarter-staggered collagen fibril, suggesting a multivalent interaction between fibromodulin and several collagen helices. Furthermore, we detected an interaction between fibromodulin and lysyl oxidase - a major collagen cross-linking enzyme - and mapped the interaction site to 12 N-terminal amino acids on fibromodulin. This interaction also increases the activity of lysyl oxidase. Altogether, the data suggest a fibromodulin-modulated collagen cross-linking mechanism, where fibromodulin binds to a specific part of the collagen domain and also forms a complex together with lysyl oxidase, targeting the enzyme towards specific cross-linking sites.SK and KR were supported by grants from the Swedish Cancer Foundation, the Swedish Research Council, the Alfred Österlund Foundation, the Crafoord Foundation, the Magnus Bergvall Foundation, and the Åke Wiberg Foundation; AB, DB and RWF by grants from the Wellcome Trust (094470/Z/10/Z) and British Heart Foundation (RG/15/4/31268).This is the final version of the article. It first appeared from the American Society for Biochemistry and Molecular Biology] via http://dx.doi.org/10.1074/jbc.M115.69340
Ecological direct action and the nature of anarchism : explorations from 1992 to 2005
In this thesis I study the radical environmental movement, of which I am part, by combining the analysis of texts and the textual record of discussions with my own extensive participant observation. More specifically, I look at the direct action undertaken by radical eco-activists and examine the relationship between this and the anarchist tradition. My research demonstrates, first, that anarchism is alive and well, albeit in a somewhat modified form from the `classical anarchism' of the 19th and early 20th centuries. In researching today's direct activists, therefore, I have also been examining the nature of anarchism itself. I show that anarchism is to be found most strongly in the dialogue that takes place between activists on the ground, engaged in practical struggles. It is from here, in the strategic debates, self-produced pamphlets, and open-ended discussions of radical environmentalists focussed on practical and immediate issues, that I draw much of my data and ideas. In pursuing this project, I present an understanding of anarchism as a pluralistic and dynamic discourse in which there is no single, correct line on each issue. Instead, the vigour of anarchism is revealed through the dissent and reflexive debate of its practitioners. This understanding of anarchism, while contrary to a static project of ideological mapping or comprehensive summary of a tradition, may be in keeping with both contemporary theory, and also the anarchist tradition itself. To pursue this understanding of anarchism, I elaborate an `anarchist methodology of research' which is both collective and subjective, ethically-bounded and reflexive. This draws on the experience of politically engaged researchers who have sought to draw lines of consistency between their ideals and the practice of research. The various forms of ecological direct action manifested in the UK between 1992 and 2005 provide the main source material for this thesis. I survey the practice and proclamations of anti-roads protesters, Earth First!, GM crop-trashers, peat saboteurs, Reclaim the Streets and others, particularly my own local group, `Tyneside Action for People and Planet'. Also considered are the explicitly anarchist organisations of the UK, and the direct action wings of related social movements. Comparison with these non-ecological movements serves to highlight influences, alternatives and criticisms across the cultures of anarchistic direct action, and contributes to the overall diversity of the anarchism studied.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
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