30 research outputs found

    Towards Interpretable Machine Learning for Automated Damage Detection Based on Ultrasonic Guided Waves

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    Data-driven analysis for damage assessment has a large potential in structural health monitoring (SHM) systems, where sensors are permanently attached to the structure, enabling continuous and frequent measurements. In this contribution, we propose a machine learning (ML) approach for automated damage detection, based on an ML toolbox for industrial condition monitoring. The toolbox combines multiple complementary algorithms for feature extraction and selection and automatically chooses the best combination of methods for the dataset at hand. Here, this toolbox is applied to a guided wave-based SHM dataset for varying temperatures and damage locations, which is freely available on the Open Guided Waves platform. A classification rate of 96.2% is achieved, demonstrating reliable and automated damage detection. Moreover, the ability of the ML model to identify a damaged structure at untrained damage locations and temperatures is demonstrated

    PIA - A Concept for a Personal Information Assistant for Data Analysis and Machine Learning of Time-Continuous Data in Industrial Applications

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    A database with high-quality data must be given to fully use the potential of Artificial Intelligence (AI). Especially in small and medium-sized companies with little experience with AI, the underlying database quality is often insufficient. This results in an increased manual effort to process the data before using AI. In this contribution, the authors developed a concept to enable inexperienced users to perform a first data analysis project with machine learning and record data with high quality. The concept comprises three modules: accessibility of (meta)data and knowledge, measurement and data planning, and data analysis. Furthermore, the concept was implemented as a front-end demonstrator on the example of an assembly station and published on the GitHub platform for potential users to test and review the concept

    Transesophageal echocardiography-guided versus fluoroscopy-guided patent foramen ovale closure : A single center registry

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    Percutaneous closure of patent foramen ovale (PFO) is conventionally performed under continuous transesophageal echocardiographic (TEE) guidance. We aimed to evaluate whether a simplified procedural approach, including pure fluoroscopy-guidance and final TEE control, as well as an aimed 'next-day-discharge' is comparable with the conventional TEE-guided procedure in terms of periprocedural and intermediate-term outcomes.All patients who underwent a PFO closure at our center between 2010 and 2022 were retrospectively included. Prior to June 2019 cases were performed with continuous TEE guidance (TEE-guided group). Since June 2019, only pure fluoroscopy-guided PFO closures have been performed with TEE insertion and control just prior to device release (fluoroscopy-guided group). We analyzed procedural aspects, as well as long term clinical and echocardiographic outcomes.In total 291 patients were included in the analysis: 197 in the TEE-guided group and 94 in the fluoroscopy-guided group. Fluoroscopy-guided procedures were markedly shorter (48 ± 20 min vs. 25 ± 9 min; p < .01). There was no difference in procedural complications, including death, major bleeding, device dislodgement, stroke or clinically relevant peripheral embolization between the two groups (.5% vs. 0%; p = .99). Hospital stay was also shorter with the simplified approach (2.5 ± 1.6 vs. 3.5 ± 1.2 days; p < .01), allowing 85% same-day discharges during the last 12 months of observation period. At 6 ± 3 months echocardiographic follow-up a residual leakage was described in 8% of the TEE-guided cases and 2% of the fluoroscopy-guided cases (p = .08).While a complete TEE-free PFO closure might have potential procedural risks, our approach of pure fluoroscopy-guided with a brisk final TEE check seems to be advantageous in terms of procedural aspects with no sign of any acute or intermediate-term hazard and it could offer an equitable compromise between the two worlds: a complete TEE procedure and a procedure without any TEE

    Risk governance in organizations

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    Dieses Buch dokumentiert 10 Jahre Risk-Governance-Forschung an der Universität Siegen. In 50 Beiträgen reflektieren Forscher und Praktiker Risk Governance vor dem Hintergrund ihrer eigenen Forschungen und/oder Erfahrungen und geben jeweils einen Entwicklungsimpuls für die Zukunft der Risk Governance. Das Buch zeigt die große Bandbreite und Tiefe des Forschungsgebietes auf und diskutiert Grundannahmen, Implementierungsfragen, die Rolle der Risk Governance als Transformationsmotor, ihre Wirkung in den verschiedenen betrieblichen Funktionen, Entwicklungsperspektiven und den Beitrag der Risk Governance zu einer nachhaltigen Ausrichtung von Unternehmen.This book documents 10 years of risk governance research at the University of Siegen. In 50 contributions, researchers and practitioners reflect on risk governance against the background of their own research and/or experience and provide a development impetus for the future of risk governance. The book shows the wide range and depth of the research field and discusses basic assumptions, implementation issues, the role of risk governance as transformation engine, its impact in the various operational functions, development perspectives, and the contribution of risk governance to a sustainable orientation of companies

    Widening of the genetic and clinical spectrum of Lamb-Shaffer syndrome, a neurodevelopmental disorder due to SOX5 haploinsufficiency

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    Purpose Lamb-Shaffer syndrome (LAMSHF) is a neurodevelopmental disorder described in just over two dozen patients with heterozygous genetic alterations involving SOX5, a gene encoding a transcription factor regulating cell fate and differentiation in neurogenesis and other discrete developmental processes. The genetic alterations described so far are mainly microdeletions. The present study was aimed at increasing our understanding of LAMSHF, its clinical and genetic spectrum, and the pathophysiological mechanisms involved. Methods Clinical and genetic data were collected through GeneMatcher and clinical or genetic networks for 41 novel patients harboring various types ofSOX5 alterations. Functional consequences of selected substitutions were investigated. Results Microdeletions and truncating variants occurred throughout SOX5. In contrast, most missense variants clustered in the pivotal SOX-specific high-mobility-group domain. The latter variants prevented SOX5 from binding DNA and promoting transactivation in vitro, whereas missense variants located outside the high-mobility-group domain did not. Clinical manifestations and severity varied among patients. No clear genotype-phenotype correlations were found, except that missense variants outside the high-mobility-group domain were generally better tolerated. Conclusions This study extends the clinical and genetic spectrum associated with LAMSHF and consolidates evidence that SOX5 haploinsufficiency leads to variable degrees of intellectual disability, language delay, and other clinical features

    Peri-operative red blood cell transfusion in neonates and infants: NEonate and Children audiT of Anaesthesia pRactice IN Europe: A prospective European multicentre observational study

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    BACKGROUND: Little is known about current clinical practice concerning peri-operative red blood cell transfusion in neonates and small infants. Guidelines suggest transfusions based on haemoglobin thresholds ranging from 8.5 to 12 g dl-1, distinguishing between children from birth to day 7 (week 1), from day 8 to day 14 (week 2) or from day 15 (≥week 3) onwards. OBJECTIVE: To observe peri-operative red blood cell transfusion practice according to guidelines in relation to patient outcome. DESIGN: A multicentre observational study. SETTING: The NEonate-Children sTudy of Anaesthesia pRactice IN Europe (NECTARINE) trial recruited patients up to 60 weeks' postmenstrual age undergoing anaesthesia for surgical or diagnostic procedures from 165 centres in 31 European countries between March 2016 and January 2017. PATIENTS: The data included 5609 patients undergoing 6542 procedures. Inclusion criteria was a peri-operative red blood cell transfusion. MAIN OUTCOME MEASURES: The primary endpoint was the haemoglobin level triggering a transfusion for neonates in week 1, week 2 and week 3. Secondary endpoints were transfusion volumes, 'delta haemoglobin' (preprocedure - transfusion-triggering) and 30-day and 90-day morbidity and mortality. RESULTS: Peri-operative red blood cell transfusions were recorded during 447 procedures (6.9%). The median haemoglobin levels triggering a transfusion were 9.6 [IQR 8.7 to 10.9] g dl-1 for neonates in week 1, 9.6 [7.7 to 10.4] g dl-1 in week 2 and 8.0 [7.3 to 9.0] g dl-1 in week 3. The median transfusion volume was 17.1 [11.1 to 26.4] ml kg-1 with a median delta haemoglobin of 1.8 [0.0 to 3.6] g dl-1. Thirty-day morbidity was 47.8% with an overall mortality of 11.3%. CONCLUSIONS: Results indicate lower transfusion-triggering haemoglobin thresholds in clinical practice than suggested by current guidelines. The high morbidity and mortality of this NECTARINE sub-cohort calls for investigative action and evidence-based guidelines addressing peri-operative red blood cell transfusions strategies. TRIAL REGISTRATION: ClinicalTrials.gov, identifier: NCT02350348

    Intrinsic properties of a KlenTaq DNA polymerase mutant with enhanced substrate specificity determined by X-ray structure analysis

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    The catalytically active Klenow fragment of an evolved Thermus aquaticus DNA polymerase I (KlenTaq) with enhanced substrate specificity was structurally investigated during this Ph.D. thesis. The wild-type KlenTaq is not able to amplify DNA damages like abasic sites or 8-oxo guanine and exhibits no lesion bypass activity. An evolved Thermus aquaticus (Taq) DNA polymerase with an exchange of a hydrophobic methionine to a cationic lysine at position 747 was achieved in the AG Marx and described in detail by C. Gloeckner. This single amino acid mutation led to an enzyme which can process such damaged DNA. Patel et al. found in the KlenTaq a mutation at a different position, I614K, which interestingly exhibits similar properties. This mutant was integrated in the KlenTaq M747K mutant and characterized by C. Gloeckner. This KlenTaq M747K, I614K mutant possessed a better lesion bypass ability combined with a high processivity.The aim of this work in structural biology was to explain the differences between the functional properties of the mutated protein and the wild-type. Therefore, the proteins were crystallized and measured at the synchrotron, either the European Synchrotron Radiation Facility, ESRF, in Grenoble, France, or the Swiss Light Source, SLS, in Villigen, Switzerland.A resolution of up to 1.7 Å was obtained in this work. Until now, this is the highest resolution achieved for the Klenow fragment of the Thermus aquaticus DNA polymerase I. One structure of the KlenTaq in the open, uncomplexed form, three structures in the closed form in complex with primer/template and dideoxynucleotidetriphosphate (ddNTP) and two structures in the closed form in complex with primer/abasic template and ddNTP were solved.The structures reveal, that the higher positive charge of the polymerase at position 747 obviously results in a tighter binding of the DNA. This stronger positive potential is also observed in the translesion bypass polymerases (e.g. DPO4 - polymerase), whereas the family I DNA polymerases exhibit a less stronger positive potential in the DNA binding region. Moreover, a hydrogen bond network could be observed, which is absent in the wild-type. This also seems to contribute to a tighter binding of the protein to the template.Interestingly, in the structure of the KlenTaq M747K, I614K in complex with p/t and ddATP there is again a nonpolar to cationic exchange from isoleucine to lysine at position 614.Lysine 614 interacts with a hydrogen bond network with motif C and motif C is responsible for the binding of the metal ions, which are responsible for the incorporation of the triphosphate and for the dephosphorylation step. This interaction seems to trap the binding pocket in a more open conformation. In the KlenTaq M747K, I614K structure, bound to a stabilized abasic site template, this hydrogen bond network was visible, too, and the phenyl ring of tyrosine 671 is in the position of the absent coding base of the template. Opposite this tyrosine, an adenosintriphosphate is bound to the incorporation site via a hydrogen bond and base stacks between the adjacent nucleobase of the 3'- end of the primer and F667 from the protein. This is the first time, that such an incorporation opposite an abasic site was ever observed in a crystal structure. Soaking experiments with ddGTP instead of the bound ddATP led to a structure, where the guanosine is incorporated opposite the abasic site. The incorporated guanosine is hydrogen bonded to glutamate 615, while the adenosine hydrogen bonds to aspartate 785. The ten times higher rate of incorporation of adenosine compared to guanosine may be due to intrinsic properties of these purines. The better solvation of adenosine together with the lower hydration energy and the superior base stacking explains the higher incorporation rate compared with guanosine. Moreover, replicative polymerases enclose at the 3'- end of the DNA primer adenosine overhangs following the A-rule. The A-rule can also be explained by the tyrosine mimicking pyrimidine

    Structures of DNA Polymerases caught processing size-augmented nucleotide probes

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    The integrity of the genome relies primarily on the ability of DNA polymerases to efficiently catalyze selective DNA synthesis according to the Watson Crick rule in a templatedirected manner during DNA replication, repair, and recombination. Remarkably, some DNA polymerases achieve selective information transfer to the offspring in line with the Watson Crick rule with intrinsic error rates as low as one mistake per one million synthesized nucleotides.[1] This is far below the value that would be expected based on the energetic differences between canonical (i.e. Watson Crick) and noncanonical nucleobase pairing.[1] Geometric factors are widely cited to govern DNA polymerase selectivity.[1] Thus, high-fidelity DNA polymerases are believed to mostly select the canonical nucleotide based on close steric complementarity of the nascent base pair to the geometry of the active site of the enzyme

    Strukturen von DNA-Polymerasen mit 4 -alkylierten Nucleotiden im aktiven Zentrum

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    Die Integrität des Genoms basiert größtenteils auf der Fähigkeit von DNA-Polymerasen, die templatabhängige DNASynthese während der DNA-Replikation, -Reparatur und -Rekombination selektiv nach der Watson-Crick-Regel zu katalysieren. Manchen DNA-Polymerasen gelingt die selektive Informationsweitergabe an die Nachkommen nach der Watson-Crick-Regel mit einer intrinsischen Fehlerrate von nur einem Fehler pro eine Million synthetisierter Nucleotide.[1] Diese Rate liegt wesentlich unter dem Wert, den man erwarten würde, wenn man hauptsächlich die energetischen Unterschiede zwischen kanonischer (d. h.Watson-Crick-) und nichtkanonischer Paarung der Nucleobasen berücksichtigt.[1] Als maßgebend für die Selektivität von DNA-Polymerasen gelten weitgehend geometrische Faktoren.[1] So nimmt man an, dass sehr selektive DNA-Polymerasen kanonische Nucleotide aufgrund genauer sterischer Komplementarität des neu gebildeten Basenpaars zum aktiven Zentrum des Enzyms selektieren
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