110 research outputs found

    Visual Turn: The Emergence of the Concept from the ‹Grammar of Seeing›

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    Angesichts der Frage nach Bildern und Bildpraxen analysiert der Beitrag von Wolfgang Wein aus der Perspektive eines rationalistischen Neukantianismus die Rolle und Funktion von visuellen Begriffen wie Einbildung, Anschauung oder Vorstellung. Dabei geht es vor allem darum, gegen jede Widerspiegelungstheorie die aktive Seite des Sehens herauszuarbeiten, um auch aus Sicht der Evolutionstheorie zu betonen, dass im Sinne des visual turn von der Primordialität des Visuellen auch angesichts von Begriffen auszugehen ist. Insgesamt geht es dabei im Rückgriff auf Kant um eine Grammatik des Sehens.In view of the question of images and image practices, Wolfgang Wein’s contribution analyzes the role and function of visual concepts such as imagination, “Anschauung”, or “Vorstellung” from the perspective of a rationalist neo-Kantianism. The main aim is to work out the active side of seeing against any theory of reflection, in order to emphasize, also from the perspective of evolutionary theory, that in the sense of the visual turn, the primordiality of the visual is to be assumed even in the face of concepts. All in all, it is a matter of a grammar of seeing with recourse to Kant

    Light-cone distribution amplitudes of the baryon octet

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    We present results of the first ab initio lattice QCD calculation of the normalization constants and first moments of the leading twist distribution amplitudes of the full baryon octet, corresponding to the small transverse distance limit of the associated S-wave light-cone wave functions. The P-wave (higher twist) normalization constants are evaluated as well. The calculation is done using Nf=2+1N_f=2+1 flavors of dynamical (clover) fermions on lattices of different volumes and pion masses down to 222 MeV. Significant SU(3) flavor symmetry violation effects in the shape of the distribution amplitudes are observed.Comment: Update to the version published in JHE

    Light-cone distribution amplitudes of octet baryons from lattice QCD

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    We present lattice QCD results for the wave function normalization constants and the first moments of the distribution amplitudes for the lowest-lying baryon octet. The analysis is based on a large number of Nf=2+1N_f=2+1 ensembles comprising multiple trajectories in the quark mass plane including physical pion (and kaon) masses, large volumes, and, most importantly, five different lattice spacings down to a=0.039fma=0.039\,\mathrm{fm}. This allows us to perform a controlled extrapolation to the continuum and infinite volume limits by a simultaneous fit to all available data. We demonstrate that the formerly observed violation of flavor symmetry breaking constraints can, indeed, be attributed to discretization effects that vanish in the continuum limit

    Разработка технологии изготовления детали «Гайка поджимная»

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    В работе рассматривается проектирование технологического процесса изготовления детали "гайка поджимная" из титана ВТ6. В технологическом разделе проводится анализ технологичности конструкции данной детали и разрабатывается технологический процесс ее изготовления. В конструкторском разделе приведено спроектированное приспособление для фиксации заготовки во время фрезерования. В экономическом разделе составлена таблица оценочной конкурентоспособности, произведен SWOT-анализ, составлен график Ганта, рассчитаны затраты на материальные расходы при изготовлении детали. В разделе "Социальная ответственность" рассмотрены вопросы экологичности и безопасности.The paper discusses the design process of manufacturing parts "gayga gland" of titanium VT6. The technological section analyzes the technological design of the part and develops the technological process of its manufacture. The design section shows the designed fixture for fixing the workpiece during milling. In the economic section, a table of estimated competitiveness has been compiled, a SWOT analysis has been carried out, a Gantt chart has been compiled, and material costs have been calculated for the manufacture of the part. In the section "Social Responsibility" addressed issues of environmental and safety

    Autonomous Robotic Screening of Tubular Structures based only on Real-Time Ultrasound Imaging Feedback

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    Ultrasound (US) imaging is widely employed for diagnosis and staging of peripheral vascular diseases (PVD), mainly due to its high availability and the fact it does not emit radiation. However, high inter-operator variability and a lack of repeatability of US image acquisition hinder the implementation of extensive screening programs. To address this challenge, we propose an end-to-end workflow for automatic robotic US screening of tubular structures using only the real-time US imaging feedback. We first train a U-Net for real-time segmentation of the vascular structure from cross-sectional US images. Then, we represent the detected vascular structure as a 3D point cloud and use it to estimate the longitudinal axis of the target tubular structure and its mean radius by solving a constrained non-linear optimization problem. Iterating the previous processes, the US probe is automatically aligned to the orientation normal to the target tubular tissue and adjusted online to center the tracked tissue based on the spatial calibration. The real-time segmentation result is evaluated both on a phantom and in-vivo on brachial arteries of volunteers. In addition, the whole process is validated both in simulation and physical phantoms. The mean absolute radius error and orientation error (±\pm SD) in the simulation are 1.16±0.1 mm1.16\pm0.1~mm and 2.7±3.32.7\pm3.3^{\circ}, respectively. On a gel phantom, these errors are 1.95±2.02 mm1.95\pm2.02~mm and 3.3±2.43.3\pm2.4^{\circ}. This shows that the method is able to automatically screen tubular tissues with an optimal probe orientation (i.e. normal to the vessel) and at the same to accurately estimate the mean radius, both in real-time.Comment: Accepted for publication in IEEE Transactions on Industrial Electronics Video: https://www.youtube.com/watch?v=VAaNZL0I5i

    Treatment of Adult Spasticity With Botox (onabotulinumtoxinA): Development, Insights, and Impact

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    Upper and lower limb spasticity (ULS, LLS) often occur following a stroke or in patients with other neurological disorders, leading to difficulties in mobility and daily living and decreased quality of life. Prior to the use of onabotulinumtoxinA, antispastic medications had limited efficacy and often caused sedation. Phenol injections were difficult for physicians to perform, painful, and led to tissue destruction. The success of onabotulinumtoxinA in treating cervical dystonia led to its use in spasticity. However, many challenges characterized the development of onabotulinumtoxinA for adult spasticity. The wide variability in the presentation of spasticity among patients rendered it difficult to determine which muscles to inject and how to measure improvement. Another challenge was the initial refusal of the Food and Drug Administration to accept the Ashworth Scale as a primary endpoint. Additional scales were designed to incorporate a goal-oriented, patient-centered approach that also accounted for the variability of spasticity presentations. Several randomized, double-blind, placebo-controlled trials of post-stroke spasticity of the elbow, wrist, and/or fingers showed significantly greater improvements in the modified Ashworth Scale and patient treatment goals and led to the approval of onabotulinumtoxinA for the treatment of ULS in adult patients. Lessons learned from the successful ULS trials were applied to design an LLS trial that led to approval for the latter indication. Additional observational trials mimicking real-world treatment have shown continued effectiveness and patient satisfaction. The use of onabotulinumtoxinA for spasticity has ushered in a more patient-centered treatment approach that has vastly improved patients\u27 quality of life

    The Many Facets of SDF-1α, CXCR4 Agonists and Antagonists on Hematopoietic Progenitor Cells

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    Stromal cell-derived factor-1alpha (SDF-1α) has pleiotropic effects on hematopoietic progenitor cells (HPCs). We have monitored podia formation, migration, proliferation, and cell-cell adhesion of human HPC under the influence of SDF-1α, a peptide agonist of CXCR4 (CTCE-0214), a peptide antagonist (CTCE-9908), and a nonpeptide antagonist (AMD3100). Whereas SDF-1α induced migration of CD34+ cells in a dose-dependent manner, CTCE-0214, CTCE-9908, and AMD3100 did not induce chemotaxis in this concentration range albeit the peptides CTCE-0214 and CTCE-9908 increased podia formation. Cell-cell adhesion of HPC to human mesenchymal stromal cells was impaired by the addition of SDF-1α, CTCE-0214, and AMD3100. Proliferation was not affected by SDF-1α or its analogs. Surface antigen detection of CXCR4 was reduced upon treatment with SDF-1α or AMD3100 and it was enhanced by CTCE-9908. Despite the fact that all these molecules target the same CXCR4 receptor, CXCR4 agonists and antagonists have selective effects on different functions of the natural molecule

    An automated optimization pipeline for clinical-grade computer-assisted planning of high tibial osteotomies under consideration of weight-bearing

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    3D preoperative planning for high tibial osteotomies (HTO) has increasingly replaced 2D planning but is complex, time-consuming and therefore expensive. Several interdependent clinical objectives and constraints have to be considered, which often requires multiple rounds of revisions between surgeons and biomedical engineers. We therefore developed an automated preoperative planning pipeline, which takes imaging data as an input to generate a ready-to-use, patient-specific planning solution. Deep-learning based segmentation and landmark localization was used to enable the fully automated 3D lower limb deformity assessment. A 2D-3D registration algorithm allowed the transformation of the 3D bone models into the weight-bearing state. Finally, an optimization framework was implemented to generate ready-to use preoperative plannings in a fully automated fashion, using a genetic algorithm to solve the multi-objective optimization (MOO) problem based on several clinical requirements and constraints. The entire pipeline was evaluated on a large clinical dataset of 53 patient cases who previously underwent a medial opening-wedge HTO. The pipeline was used to automatically generate preoperative solutions for these patients. Five experts blindly compared the automatically generated solutions to the previously generated manual plannings. The overall mean rating for the algorithm-generated solutions was better than for the manual solutions. In 90% of all comparisons, they were considered to be equally good or better than the manual solution. The combined use of deep learning approaches, registration methods and MOO can reliably produce ready-to-use preoperative solutions that significantly reduce human workload and related health costs
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