334 research outputs found
COMPUTED TOMOGRAPHY BASED PREDICTION OF ANGIOGRAPHIC DEPLOYMENT ANGLES MAY REDUCE PROCEDURE TIME AND CONTRAST MEDIUM VOLUME FOR TRANSCATHETER AORTIC VALVE REPLACEMENT
Planas Calvet, LluísPrimer pla d'edifici unifamiliar, de dos habitatges
adossats.De planta baixa, planta pis i golfes,
i una torrassa adossada. Són de gran qualitat
els esgrafiats del número 8 i les elaborades
reixes de ferro forjat del número 10
Caressing the Earth: Of Maps and Mice, Flowers and Feet
This joint article draws on artistic practices that showcase how relations to nature can articulate rituals of care and reciprocity in embodied experiences and sympoesis. It discusses active approaches to practicing sympathetic interaction with Nature by challenging our habitual processes of forming connection. The paper revolves around modes of exploitation in animal experiments and the lack of emotional knowledge and connection in science, in The Touch ofSoil by Dominik Fleischmann; and advocates for attention to soil, in Palpating Landscape by celine s diaz, as ritualistic extension of inclusiveness for thelandscape. Through creative writing, theoretic reflection and the photographic medium, both unravel deep concerns for the human-centred approach of viewing and engaging with the natural world and its habitants and advocate for a broader agency, action invoked in caring. Finding overlapping questions, this paper shows two practices of responsibility as empathy and care are evermore significant in our relationship with nature. These vulnerable acts comprehenddisruptive temporalities and propose a kinder but equally relevant message: “I care”
Finteam - A React Native App for Fiduciaries and their clients
Introduction
In Switzerland, tax filing is often perceived as a cumbersome process, which leads many individuals to delegate this responsibility to fiduciaries. However, this delegation introduces its own inefficiencies, particularly in the form of unstructured communication and incomplete documentation, which impair the ability of fiduciaries to work efficiently.
Approach and technology
This thesis presents the development of Finteam, a Minimum Viable Product (MVP) designed to streamline document exchange and communication between clients and fiduciaries. Starting from a basic prototype, the project improved the architecture, added core features, and developed a scalable backend to support future growth. The system consists of three main components: first, a mobile app (built with React Native and Expo) for clients to upload tax documents and interact with an AI assistant. Second, a web app (React + TypeScript) for fiduciaries to manage client submissions and provide feedback. Third, a modular backend (Express.js + TypeScript) that handles authentication, data storage, and an RAG-based tax assistant.
Conclusion
During this thesis, the team successfully developed an MVP for the Finteam application. The system replaces unstructured communication with a digital workflow that reduces administrative overhead on both sides. The mobile application enables clients to upload tax documents, while the web platform provides fiduciaries tye ability to review submissions and send feedback to the client. This approach eliminates the typical back-and-forth email exchanges that currently affect fiduciaries.
As a secondary but notable feature, the system incorporates an AI-powered tax assistant built on Retrieval-Augmented Generation (RAG) technology integrated into the mobile app. It combines vector- and keyword-based search with reranking and query rewriting techniques to improve response quality. An empirical evaluation of various configurations showed that reranking significantly enhanced the accuracy of responses. While this came with a latency trade-off of approximately 38% compared to vector-only retrieval, which served as a baseline. With this tradeoff, the overall user experience benefited from more relevant answers. Key evaluation criteria included helpfulness, correctness, clarity, and fluency.
Key limitations include the absence of a scalable fiduciary onboarding flow and restricted iOS deployment due to the lack of access to Apple's Developer Program. Future work should focus on automating onboarding, enabling administrative oversight, integrating document parsing to prefill tax forms, and at-rest encryption of user documents to enhance security
Cryogenic electron microscopy workflows for the characterization of electrochemical interfaces and interphases in batteries
Hemodynamic Effects of Entry and Exit Tear Size in Aortic Dissection Evaluated with In Vitro Magnetic Resonance Imaging and Fluid-Structure Interaction Simulation
Understanding the complex interplay between morphologic and hemodynamic
features in aortic dissection is critical for risk stratification and for the
development of individualized therapy. This work evaluates the effects of entry
and exit tear size on the hemodynamics in type B aortic dissection by comparing
fluid-structure interaction (FSI) simulations with in vitro 4D-flow magnetic
resonance imaging (MRI). A baseline patient-specific 3D-printed model and two
variants with modified tear size (smaller entry tear, smaller exit tear) were
embedded into a flow- and pressure-controlled setup to perform MRI as well as
12-point catheter-based pressure measurements. The same models defined the wall
and fluid domains for FSI simulations, for which boundary conditions were
matched with measured data. Results showed exceptionally well matched complex
flow patterns between 4D-flow MRI and FSI simulations. Compared to the baseline
model, false lumen flow volume decreased with either a smaller entry tear
(-17.8 and -18.5 %, for FSI simulation and 4D-flow MRI, respectively) or
smaller exit tear (-16.0 and -17.3 %). True to false lumen pressure difference
(initially 11.0 and 7.9 mmHg, for FSI simulation and catheter-based pressure
measurements, respectively) increased with a smaller entry tear (28.9 and 14.6
mmHg), and became negative with a smaller exit tear (-20.6 and -13.2 mmHg).
This work establishes quantitative and qualitative effects of entry or exit
tear size on hemodynamics in aortic dissection, with particularly notable
impact observed on FL pressurization. FSI simulations demonstrate acceptable
qualitative and quantitative agreement with flow imaging, supporting its
deployment in clinical studies.Comment: Judith Zimmermann and Kathrin B\"aumler contributed equall
Low-dose coronary calcium scoring CT using a dedicated reconstruction filter for kV-independent calcium measurements
In this prospective, pilot study, we tested a kV-independent coronary artery calcium scoring CT protocol, using a novel reconstruction kernel (Sa36f). From December 2018 to November 2019, we performed an additional research scan in 61 patients undergoing clinical calcium scanning. For the standard protocol (120 kVp), images were reconstructed with a standard, medium-sharp kernel (Qr36d). For the research protocol (automated kVp selection), images were reconstructed with a novel kernel (Sa36f). Research scans were sequentially performed using a higher (cohort A, n = 31) and a lower (cohort B, n = 30) dose optimizer setting within the automatic system with customizable kV selection. Agatston scores, coronary calcium volumes, and radiation exposure of the standard and research protocol were compared. A phantom study was conducted to determine inter-scan variability. There was excellent correlation for the Agatston score between the two protocols (r = 0.99); however, the standard protocol resulted in slightly higher Agatston scores (29.4 [0-139.0] vs 17.4 [0-158.2], p = 0.028). The median calcium volumes were similar (11.5 [0-109.2] vs 11.2 [0-118.0] mm(3); p = 0.176), and the number of calcified lesions was not significantly different (p = 0.092). One patient was reclassified to another risk category. The research protocol could be performed at a lower kV and resulted in a substantially lower radiation exposure, with a median volumetric CT dose index of 4.1 vs 5.2 mGy, respectively (p < 0.001). Our results showed that a consistent coronary calcium scoring can be achieved using a kV-independent protocol that lowers radiation doses compared to the standard protocol
The Use of Intraosseous Needles for Injection of Contrast Media for Computed Tomographic Angiography of the Thoracic Aorta
Background
The objective of this study is to evaluate the safety and quality of computed tomographic angiography of the thoracic aorta (CTA-TA) exams performed using intraosseous needle intravenous access (ION-IVA) for contrast media injection (CMI).
Methods
All CTA-TA exams at the study institution performed between 1/1/2013 and 8/14/2015 were reviewed retrospectively to identify those exams which had been performed using ION-IVA (ION-exams). ION-exams were then analyzed to determine aortic attenuation and contrast-to-noise ratio (CNR). Linear regression was used to determine how injection rate and other variables affected image quality for ION-exams. Patient electronic medical records were reviewed to identify any adverse events related to CTA-TA or ION-IVA.
Results
17 (∼0.2%) of 7401 exams were ION-exams. ION-exam CMI rates varied between 2.5 and 4 ml/s. Mean attenuation was 312 HU (SD 88 HU) and mean CNR was 25 (SD 9.9). A strong positive linear association between attenuation and injection rate was found. No immediate or delayed complications related to the ION-exams, or intraosseous needle use in general, occurred.
Conclusion
For CTA-TA, ION-IVA appears to be a safe and effective route for CMI at rates up to 4 ml/s
Assessment of aortic dissection remodeling with patient-specific fluid–structure interaction models
Aortic dissection leads to late complications due tochronic degeneration and dilatation of the false lumen. This study examines the interaction between hemodynamics and long-term remodeling of a patient's aortic dissection, tracked from pre-dissection to the chronic phase using CT angiography. Fluid–structure interaction models with tissue prestress, external support, and anisotropic properties were used to analyze hemodynamic markers. Each aortic wall layer had distinct thicknesses and material properties. The boundary conditions were guided by in vitro 4D-flow MRI and the patient's blood pressure. Aortic dilatation was most significant distal to the left subclavian artery, reaching 6 cm in the chronic phase. Simulations quantified the flow jet velocity through the entry tear, which peaked at 185 cm/s in the subacute phase and decreased to 123 to 133 cm/s in the chronic phase, corresponding to an increased entry tear size. Flow jet impingement on the false lumen resulted in a localized pressure increase of 11 and 2 mmHg in the subacute and chronic phases, with wall shear stress reaching 4 Pa. These hemodynamic changes appear to be the main drivers of aortic growth and morphological changes. Despite moderate overall flap movement, in-plane displacement increased from 0.6 to 1.8 mm as disease progressed, which was associated with an overall increase in aortic diameter. Simulations with a significant reduction in flap stiffness during the subacute phase resulted in increased flap motion up to 9.5 mm. Although these results are based on a single patient, they suggest a strong relationship between hemodynamics and aortic growth
Degeneration of Lumbar Intervertebral Discs: Characterization of Anulus Fibrosus Tissue and Cells of Different Degeneration Grades
Intervertebral disc (IVD) herniation and degeneration is a major source of back pain. In order to regenerate a herniated and degenerated disc, closure of the anulus fibrosus (AF) is of crucial importance. For molecular characterization of AF, genome-wide Affymetrix HG-U133plus2.0 microarrays of native AF and cultured cells were investigated. To evaluate if cells derived from degenerated AF are able to initiate gene expression of a regenerative pattern of extracellular matrix (ECM) molecules, cultivated cells were stimulated with bone morphogenetic protein 2 (BMP2), transforming growth factor β1 (TGFβ1) or tumor necrosis factor-α (TNFα) for 24 h. Comparative microarray analysis of native AF tissues showed 788 genes with a significantly different gene expression with 213 genes more highly expressed in mild and 575 genes in severe degenerated AF tissue. Mild degenerated native AF tissues showed a higher gene expression of common cartilage ECM genes, whereas severe degenerated AF tissues expressed genes known from degenerative processes, including matrix metalloproteinases (MMP) and bone associated genes. During monolayer cultivation, only 164 differentially expressed genes were found. The cells dedifferentiated and altered their gene expression profile. RTD-PCR analyses of BMP2- and TGFβ1-stimulated cells from mild and severe degenerated AF tissue after 24 h showed an increased expression of cartilage associated genes. TNFα stimulation increased MMP1, 3, and 13 expression. Cells derived from mild and severe degenerated tissues could be stimulated to a comparable extent. These results give hope that regeneration of mildly but also strongly degenerated disc tissue is possible
Reconstruction of primary vertices at the ATLAS experiment in Run 1 proton–proton collisions at the LHC
This paper presents the method and performance of primary vertex reconstruction in proton–proton collision data recorded by the ATLAS experiment during Run 1 of the LHC. The studies presented focus on data taken during 2012 at a centre-of-mass energy of √s=8 TeV. The performance has been measured as a function of the number of interactions per bunch crossing over a wide range, from one to seventy. The measurement of the position and size of the luminous region and its use as a constraint to improve the primary vertex resolution are discussed. A longitudinal vertex position resolution of about 30μm is achieved for events with high multiplicity of reconstructed tracks. The transverse position resolution is better than 20μm and is dominated by the precision on the size of the luminous region. An analytical model is proposed to describe the primary vertex reconstruction efficiency as a function of the number of interactions per bunch crossing and of the longitudinal size of the luminous region. Agreement between the data and the predictions of this model is better than 3% up to seventy interactions per bunch crossing
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