285 research outputs found

    Pseudo-contractions as Gentle Repairs

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    Updating a knowledge base to remove an unwanted consequence is a challenging task. Some of the original sentences must be either deleted or weakened in such a way that the sentence to be removed is no longer entailed by the resulting set. On the other hand, it is desirable that the existing knowledge be preserved as much as possible, minimising the loss of information. Several approaches to this problem can be found in the literature. In particular, when the knowledge is represented by an ontology, two different families of frameworks have been developed in the literature in the past decades with numerous ideas in common but with little interaction between the communities: applications of AGM-like Belief Change and justification-based Ontology Repair. In this paper, we investigate the relationship between pseudo-contraction operations and gentle repairs. Both aim to avoid the complete deletion of sentences when replacing them with weaker versions is enough to prevent the entailment of the unwanted formula. We show the correspondence between concepts on both sides and investigate under which conditions they are equivalent. Furthermore, we propose a unified notation for the two approaches, which might contribute to the integration of the two areas

    Optimal Fixed-Premise Repairs of EL TBoxes: Extended Version

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    Reasoners can be used to derive implicit consequences from an ontology. Sometimes unwanted consequences are revealed, indicating errors or privacy-sensitive information, and the ontology needs to be appropriately repaired. The classical approach is to remove just enough axioms such that the unwanted consequences vanish. However, this is often too rough since mere axiom deletion also erases many other consequences that might actually be desired. The goal should not be to remove a minimal number of axioms but to modify the ontology such that only a minimal number of consequences is removed, including the unwanted ones. Specifically, a repair should rather be logically entailed by the input ontology, instead of being a subset. To this end, we introduce a framework for computing fixed-premise repairs of EL\mathcal{EL} TBoxes. In the first variant the conclusions must be generalizations of those in the input TBox, while in the second variant no such restriction is imposed. In both variants, every repair is entailed by an optimal one and, up to equivalence, the set of all optimal repairs can be computed in exponential time. A prototypical implementation is provided. In addition, we show new complexity results regarding gentle repairs.This is an extended version of an article accepted at the 45th German Conference on Artificial Intelligence (KI 2022)

    Optimal Repairs in the Description Logic EL Revisited

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    Ontologies based on Description Logics may contain errors, which are usually detected when reasoning produces consequences that follow from the ontology, but do not hold in the modelled application domain. In previous work, we have introduced repair approaches for EL ontologies that are optimal in the sense that they preserve a maximal amount of consequences. In this paper, we will, on the one hand, review these approaches, but with an emphasis on motivation rather than on technical details. On the other hand, we will describe new results that address the problems that optimal repairs may become very large or need not even exist unless strong restrictions on the terminological part of the ontology apply. We will show how one can deal with these problems by introducing concise representations of optimal repairs

    Procedures in obstetrics and gynaecology

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    Book providing practical approach to broad range of procedures in obstetrics and gynaecology. Textbook relevant to fourth through six year medical students

    Tumor Cell Migration and Interaction with ECM and Stroma in 3D Tissue Models

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    Tumors are often described as ”wounds that do not heal”. Tumor progression and woundhealing both feature sustained proliferative signaling, evasion from immune destruction, cell death resistance, inflammation, angiogenesis, extracellular matrix(ECM) remodeling, and activated cell migration. Unlike normal wound healing which often ends up with restored tissue homeostasis, pathological ECM remodeling is frequently implicated in fibrotic diseases and solid tumors. In addition, the dysregulated ECM signatures are directly associated with poor prognosis and also immunotherapy failure in certain types of cancers. In this dissertation, we used 3D in vitro cocultures to understand how tumor cells co-op with stromal/immune components, how ECM remodeling is hijacked, and how ECM architecture impacts tumor progression. We first investigated the impact of fibroblasts. Fibroblasts are the most abundant cell types in the tumor stroma. The density of cancer-associated fibroblasts(CAFs) has been shown directly correlated with poor prognosis in some types of solid tumors. To uncover potential mechanisms behind the quantitative relationship between CAFs and tumor dissemination, we developed our coculture model by varying the density ratios between normal human lung fibroblasts and breast cancer cells(MDA-MB-231s). We found that fibroblasts increase tumor cell motility and facilitate the transition from confined to diffusive tumor cell motions, indicative of an uncaging effect. Furthermore, the ECM is globally and locally remodeled substantially with the presence of fibroblasts. Moreover, these fibroblast-mediated phenomena are in part dependent on matrix metalloproteinases. We then investigated the impact of macrophages. In this study, we developed a 3D collagen co-culture system to mimic the melanoma microenvironment and investigate how interactions between melanoma cancer cells, fibroblasts, and macrophages shape the early stages of macrophage immune activity. In this in vitro model, we captured the macrophage immunosuppressive transition. Macrophages in the model displayed increased motility and acquired a phenotype that was similar to tumor-associated macrophages(TAMs) from melanoma tumors. This model may provide a platform for further studies on TAMs targeted immune therapy in melanoma. In the end, we investigated the impact of ECM architecture in tumor progression. Reconstruction of a biomimetic scaffold is critical in 3D in vitro models. Here we introduce a new type of thick collagen bundles that highly mimic in vivo ECM structure. We fabricated this type of thickened collagen bundles by introducing mechanical agitation during the transient gelation process. Thickened collagen patches are interconnected with a loose collagen network, highly resembling collagen architecture in human skin scars. This type of thickened collagen bundles promotes tumor cell dissemination. The effect is significantly augmented in the presence of fibroblasts. The application of this type of collagen triggers different morphology and migration behaviors of tumor cells and highlights the importance of mesoscale architectures. Overall, this dissertation investigated the roles of stromal and non-stromal components in tumor progression through 3D in vitro models. The coculture models established in this dissertation may be further extended to test novel therapeutics targeted at CAFs, TAMs or ECM architecture

    Modifications in Early Rehabilitation Protocol after Rotator Cuff Repair : EMG Studies

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    La déchirure de la coiffe des rotateurs est une des causes les plus fréquentes de douleur et de dysfonctionnement de l'épaule. La réparation chirurgicale est couramment réalisée chez les patients symptomatiques et de nombreux efforts ont été faits pour améliorer les techniques chirurgicales. Cependant, le taux de re-déchirure est encore élevé ce qui affecte les stratégies de réhabilitation post-opératoire. Les recommandations post-chirurgicales doivent trouver un équilibre optimal entre le repos total afin de protéger le tendon réparé et les activités préconisées afin de restaurer l'amplitude articulaire et la force musculaire. Après une réparation de la coiffe, l'épaule est le plus souvent immobilisée grâce à une écharpe ou une orthèse. Cependant, cette immobilisation limite aussi la mobilité du coude et du poignet. Cette période qui peut durer de 4 à 6 semaines où seuls des mouvements passifs peuvent être réalisés. Ensuite, les patients sont incités à réaliser les exercices actifs assistés et des exercices actifs dans toute la mobilité articulaire pour récupérer respectivement l’amplitude complète de mouvement actif et se préparer aux exercices de résistance réalisés dans la phase suivante de la réadaptation. L’analyse électromyographique des muscles de l'épaule a fourni des évidences scientifiques pour la recommandation de beaucoup d'exercices de réadaptation au cours de cette période. Les activités sollicitant les muscles de la coiffe des rotateurs à moins de 20% de leur activation maximale volontaire sont considérés sécuritaires pour les premières phases de la réhabilitation. À partir de ce concept, l'objectif de cette thèse a été d'évaluer des activités musculaires de l'épaule pendant des mouvements et exercices qui peuvent théoriquement être effectués au cours des premières phases de la réhabilitation. Les trois questions principales de cette thèse sont : 1) Est-ce que la mobilisation du coude et du poignet produisent une grande activité des muscles de la coiffe? 2) Est-ce que les exercices de renforcement musculaire du bras, de l’avant-bras et du torse produisent une grande activité dans les muscles de la coiffe? 3) Au cours d'élévations actives du bras, est-ce que le plan d'élévation affecte l'activité de la coiffe des rotateurs? Dans notre première étude, nous avons évalué 15 muscles de l'épaule chez 14 sujets sains par électromyographie de surface et intramusculaire. Nos résultats ont montré qu’avec une orthèse d’épaule, les mouvements du coude et du poignet et même quelques exercices de renforcement impliquant ces deux articulations, activent de manière sécuritaire les muscles de ii la coiffe. Nous avons également introduit des tâches de la vie quotidienne qui peuvent être effectuées en toute sécurité pendant la période d'immobilisation. Ces résultats peuvent aider à modifier la conception d'orthèses de l’épaule. Dans notre deuxième étude, nous avons montré que l'adduction du bras réalisée contre une mousse à faible densité, positionnée pour remplacer le triangle d’une orthèse, produit des activations des muscles de la coiffe sécuritaires. Dans notre troisième étude, nous avons évalué l'électromyographie des muscles de l’épaule pendant les tâches d'élévation du bras chez 8 patients symptomatiques avec la déchirure de coiffe des rotateurs. Nous avons constaté que l'activité du supra-épineux était significativement plus élevée pendant l’abduction que pendant la scaption et la flexion. Ce résultat suggère une séquence de plan d’élévation active pendant la rééducation. Les résultats présentés dans cette thèse, suggèrent quelques modifications dans les protocoles de réadaptation de l’épaule pendant les 12 premières semaines après la réparation de la coiffe. Ces suggestions fournissent également des évidences scientifiques pour la production d'orthèses plus dynamiques et fonctionnelles à l’articulation de l’épaule.Rotator cuff tear is one of the most common causes of shoulder pain and dysfunction. The operative repair has been widely performed for symptomatic patients and many efforts have been done to improve the surgical techniques. However, the re-tear rate is still high and this affects post-repair rehabilitation strategies. Post-surgical care should balance between the restriction imposed to protect the repaired tendon and the activities prescribed to restore range of motion and muscle strength. Frequently, early after rotator cuff repair, shoulder is immobilized in a sling or abduction orthosis, but this immobilization includes elbow and wrist joints as well. In this period that may last 4-6 weeks, only passive range of motion exercises are performed. After removing the immobilizer, patients are encouraged to do active assisted and active range of motion exercises respectively to regain the full active range of motion and be prepared for the resistance exercises in the following phase of rehabilitation. Electromyography of shoulder muscles has provided scientific basis for many of rehabilitation exercises during this period. Anecdotally, the activities of less than 20% of the maximal voluntary contraction of rotator cuff muscles are considered safe for the first phases of rehabilitation after rotator cuff repair. Using this concept, the aim of this dissertation is to evaluate the activity of shoulder musculature during some movements and exercises that can theoretically be performed during the early phases of rehabilitation. Three main questions of this thesis are: 1) Do elbow and wrist mobilizations highly activate rotator cuff muscles? 2) Do some resistance exercises of arm, forearm and chest muscles produce high activity in rotator cuff muscles? 3) During active arm elevation, does the plane of elevation affect rotator cuff activity? In our first study, we evaluated 15 shoulder muscles in 14 healthy subjects with both surface and indwelling EMG. Our results showed that while wearing a shoulder orthosis, elbow and wrist movements and even some resistance training involving these two joints, would minimally activate the rotator cuff muscles and can be considered safe. We also introduced some daily living tasks that can be performed safely during immobilization period. These findings may help to modify the design of current shoulder orthoses. In the second study, we also showed that resisted arm adduction against a low-density foam that replaced the hard wedge of orthosis would not highly activate the cuff muscles. In our final study, we evaluated the EMG of shoulder musculature during arm elevation tasks in 8 symptomatic patients with rotator cuff tears. We found that supraspinatus activity during arm elevation is significantly higher in abduction plane than in scaption and flexion planes in patients with rotator cuff tears. This suggested a plane sequences for active range of motion exercises during rehabilitation. The findings that are presented in this dissertation, suggest some modifications in the rehabilitation protocols during the first 12 weeks after rotator cuff repair. These suggestions also provide a scientific basis for producing more dynamic and functional shoulder orthoses

    Evidence-Based Beliefs in Many-Valued Modal Logics

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    Rational agents, humans or otherwise, build their beliefs from evidence – a process which we call consolidation. But how should this process be carried out? In this thesis, we study a multi-agent logic of evidence and the question how agents should form beliefs in this logic. The main contributions of this thesis are twofold. First, we present and study a many-valued modal logic, and show how it can be suitable for modelling multi-agent scenarios where each agent has access to some evidence, which in turn can be processed into beliefs. This is a technical and practical contribution to many-valued modal logics. Second, we open new paths for research in the field of evidence logics: we show a new approach based on many-valued logics, we highlight the concept of consolidations and the importance of looking at their dynamic nature, and build a methodology based on rationality postulates to evaluate them

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    1962 Clinic Yearbook

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    The Clinic is the yearbook of the Sidney Kimmel Medical College (formerly Jefferson Medical College) at Thomas Jefferson University
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