1,650 research outputs found

    REAL-TIME MONITORING OF WIND CONVERTERS BASED ON SOFTWARE AGENTS

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    Due to increasing numbers of wind energy converters, the accurate assessment of the lifespan of their structural parts and the entire converter system is becoming more and more paramount. Lifespan-oriented design, inspections and remedial maintenance are challenging because of their complex dynamic behavior. Wind energy converters are subjected to stochastic turbulent wind loading causing corresponding stochastic structural response and vibrations associated with an extreme number of stress cycles (up to 109 according to the rotation of the blades). Currently, wind energy converters are constructed for a service life of about 20 years. However, this estimation is more or less made by rule of thumb and not backed by profound scientific analyses or accurate simulations. By contrast, modern structural health monitoring systems allow an improved identification of deteriorations and, thereupon, to drastically advance the lifespan assessment of wind energy converters. In particular, monitoring systems based on artificial intelligence techniques represent a promising approach towards cost-efficient and reliable real-time monitoring. Therefore, an innovative real-time structural health monitoring concept based on software agents is introduced in this contribution. For a short time, this concept is also turned into a real-world monitoring system developed in a DFG joint research project in the authors’ institute at the Ruhr-University Bochum. In this paper, primarily the agent-based development, implementation and application of the monitoring system is addressed, focusing on the real-time monitoring tasks in the deserved detail

    A descriptive retrospective audit of the obstetric conditions which occur in mothers of babies with neonatal encephalopathy at Mowbray Maternity Hospital in 2016

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    Introduction: Neonatal encephalopathy (NE) is an important condition which may result in mortality or severe and permanent morbidity placing much strain on busy under-resourced health care services, parents and families, and the greater community. There is much debate on its aetiology; whether it is caused by antepartum conditions or intrapartum obstetric complications (known as sentinel events); and the relative contribution of intrapartum hypoxia. Unlike perinatal mortality, NE rates are not routinely audited by maternity facilities. At Mowbray Maternity Hospital, a formal audit was conducted in 2008, which measured the NE rate, focussed on obstetric factors associated with NE and identified avoidable factors in the care provided. It was thought to be of clinical value to repeat this audit to identify whether there were any trends in rates and the pattern of obstetric factors. Aims and objectives: The aim was to describe the obstetric factors occurring in patients who delivered neonates at MMH, diagnosed with NE. Specifically, it was planned to determine the NE rate, to describe obstetric factors occurring in these patients and to assess the avoidable factors related to the patients, health system and clinical management. Methodology: This was a retrospective descriptive study which included patients whose neonates were diagnosed with NE and were born at MMH in 2016. The diagnosis of NE was made according to the MMH NE protocol where NE is defined as a voltage suppression in amplitude-integrated electroencephalography (aEEG) or seizures; or clinical seizures or dystonic movements; or moderate to severe clinical signs of NE as defined by Shankaran and a level of consciousness which is decreased with abnormal tone. The neonates’ names were retrieved from a NE register in the neonatal unit and the corresponding mothers’ folders retrieved. Data on relevant obstetric and clinical management factors were collected from the folders using a data collection tool developed in the Western Cape and all cardiotocographic tracings were assessed by the researcher. Ethics approval was granted by the University of Cape Town Human Research Ethics Committee (UCT HREC) prior to the commencement of the study. STATA 14 was used for the analysis. Results: In 2016, 53 neonates with NE were identified out of 9,702 live births (LB) at MMH. The NE rate was 5.5 per 1000 LB. Of the 53 neonates, 48 maternal patient files were retrieved and analysed. There were 58% who had been referred to MMH from the midwife obstetric units (MOUs), and 42% fully managed at MMH. All patients were booked for 14 antenatal care, the mean age was 27.5 years and 50% were nulliparous. The mean gestational age at delivery was 39 weeks. The majority (87.5%) experienced labour, spontaneous in 72.9% and induced in 14.6%. Antenatal complications occurred in 77.1%, the most frequent being prolonged pregnancy (25%) hypertensive disorders (18.8%), antepartum haemorrhage (8.3%) and prelabour rupture of membranes (8.3%). Obstetric problems in labour included prolonged second stage of labour (25% of patients who had a second stage of labour); multiple vaginal examinations (28.6%) and prolonged first stage of labour (17.9%). Fetal monitoring at the MOUs was done according to protocol in 70% of patients in the latent phase but only 12.5% of those in the active phase of labour. At MMH, all patients in labour had Cardiotocograph (CTG) monitoring with 90.6% of CTGs being pathological and 6.3% suspicious, as assessed by the researcher. Meconium stained liquor occurred in 40.5% of patients. The mode of delivery was normal vertex, (27.1%), Caesarean sections (58.3%) and assisted vaginal delivery (14.6%). Most CS (71.4%) were done for pathological CTGs. Sentinel events occurred in 15 (31.3%) patients; approximately two-thirds occurring intrapartum and one- third antenatal. Sentinel events included shoulder dystocia (10.4%), prolonged second stage of labour (10.4%), abruptio placenta (6.3%), cord prolapse (2.1%) and eclampsia (2.1%). Of the 37 (68.7%) without a sentinel event, 75.8% had a pathological CTG. Considering avoidable factors, there was an ambulance delay in 42.9%, and a delay in accessing theatre for 53.6% of patients requiring a CS. Poor quality CTG tracing and monitoring occurred in 20.8% of patients; and for 34.4%, the researcher identified an abnormal CTG but it was not detected by the attendant health care workers. Discussion and conclusion: The NE rate for MMH is 5.5 per 1000 LBs, this is higher than the 3.7 found in the previous 2008 MMH study, despite a higher CS rate. Possible reasons for the increase include changes in case ascertainment, increased workload with same staff component, or a shift from perinatal hypoxic mortality to morbidity, notably NE. This NE rate compares with other lower resource settings and the previous MMH audit, as does the high proportion of intrapartum obstetric sentinel events. This is in contrast to findings from high resource settings. Areas for service improvement include regular and ongoing intrapartum care training, including fetal heart monitoring, for medical and nursing staff; and addressing the health system issues identified

    REAL-TIME MONITORING OF WIND CONVERTERS BASED ON SOFTWARE AGENTS

    Get PDF
    Due to increasing numbers of wind energy converters, the accurate assessment of the lifespan of their structural parts and the entire converter system is becoming more and more paramount. Lifespan-oriented design, inspections and remedial maintenance are challenging because of their complex dynamic behavior. Wind energy converters are subjected to stochastic turbulent wind loading causing corresponding stochastic structural response and vibrations associated with an extreme number of stress cycles (up to 109 according to the rotation of the blades). Currently, wind energy converters are constructed for a service life of about 20 years. However, this estimation is more or less made by rule of thumb and not backed by profound scientific analyses or accurate simulations. By contrast, modern structural health monitoring systems allow an improved identification of deteriorations and, thereupon, to drastically advance the lifespan assessment of wind energy converters. In particular, monitoring systems based on artificial intelligence techniques represent a promising approach towards cost-efficient and reliable real-time monitoring. Therefore, an innovative real-time structural health monitoring concept based on software agents is introduced in this contribution. For a short time, this concept is also turned into a real-world monitoring system developed in a DFG joint research project in the authors’ institute at the Ruhr-University Bochum. In this paper, primarily the agent-based development, implementation and application of the monitoring system is addressed, focusing on the real-time monitoring tasks in the deserved detail

    Upscaling Tracer-Aided Ecohydrological Modeling to Larger Catchments : Implications for Process Representation and Heterogeneity in Landscape Organization

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    Funding Information: This work was supported by the Modular Observation Solutions for Earth Systems—MOSES project and the Terrestrial Environmental Observatories—TERENO project. Funding was also received for Doerthe Tetzlaff through the Einstein Research Unit “Climate and Water under Change” from the Einstein Foundation Berlin and Berlin University Alliance. Contributions by Chris Soulsby were supported by the Leverhulme Trust through the ISO‐LAND project (RPG 2018 375). The authors thank Michael Rode and Ralf Merz for permitting the use of the water stable isotope data and for constructive discussions related to the data analysis. The authors would like to thank Marco Maneta and Aaron Smith for their support and discussion on the modeling. The authors thank the Editor Peter Troch, the Associate Editor and three anonymous reviewers for their constructive comments. The authors also thank the German Weather Service, the Federal Institute for Geosciences and Natural Resources and the State Agency for Flood Protection and Water Management Saxony‐Anhalt for the model setup data. Open Access funding enabled and organized by Projekt DEAL. Publisher Copyright: © 2023. The Authors.Peer reviewedPublisher PD

    Implementierung eines webbasierten Talsperren-Monitoring-Systems

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    Die Bauwerksüberwachung gewinnt aus sicherheitstechnischen sowie aus wirtschaftlichen Gründen zunehmend an Bedeutung. Nicht nur die Bauwerkssicherheit kann durch leistungsfähige Monitoring-Systeme angemessen beurteilt, auch die Nutzungsdauer bestehender Bauwerke kann durch die gewonnenen Informationen deutlich verlängert werden. Das vorliegende Papier beschreibt die Entwicklung eines webbasierten Talsperren-Monitoring-Systems, das die automatisierte Erfassung von Daten vor Ort sowie die computergestützte Aufbereitung und Analyse der gesammelten Messdaten ermöglicht. Das Monitoring-System ist durch seinen modularen Aufbau nicht auf die Talsperren-Überwachung beschränkt, sondern kann ohne großen Aufwand an andere Überwachungsaufgaben angepasst werden. Das System besteht aus drei wesentlichen Modulen: (i) einer erweiterbaren Klassenbibliothek, die die Steuerung der im Bauwerk installierten Messelektronik ermöglicht, (ii) einem webbasierten Datenerfassungsmodul, das neben der automatischen Datenerfassung eine Fernsteuerung der Messelektronik erlaubt und Funktionen zur Verwaltung der Überwachungsaufgaben bereitstellt, sowie (iii) einem webbasierten Visualisierungs- und Auswertungsmodul zur Aufbereitung und Analyse der gesammelten Daten. Alle an der Überwachung beteiligten Mitarbeiter können mit einem üblichen Web-Browser über das Internet auf das entwickelte System zugreifen; ein Zugriff mittels Mobiltelefon ist alternativ möglich. Das implementierte Talsperren-Monitoring-System begleitet die beteiligten Fachleute von der Erfassung der Daten vor Ort bis hin zur Aufbereitung und Analyse der Messdaten an zentraler Stelle: Die Mitarbeiter werden durch einen einfachen Zugriff auf die installierte Messelektronik, automatisierte Messungen und umfangreiche Analysefunktionalitäten bei ihren spezifischen Aufgaben unterstützt. Der bisherige manuelle Arbeitsaufwand für Datenerfassung, -transfer und Analyse wird somit deutlich reduziert

    Altered VEGF splicing isoform balance in tumor endothelium involves activation of splicing factors Srpk1 and Srsf1 by the Wilms’ tumor suppressor Wt1

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    Angiogenesis is one hallmark of cancer. Vascular endothelial growth factor (VEGF) is a known inducer of angiogenesis. Many patients benefit from antiangiogenic therapies, which however have limitations. Although VEGF is overexpressed in most tumors, different VEGF isoforms with distinct angiogenic properties are produced through alternative splicing. In podocytes, the Wilms’ tumor suppressor 1 (WT1) suppresses the Serine/arginine-rich protein-specific splicing factor kinase (SRPK1), and indirectly Serine/arginine-rich splicing factor 1 (Srsf1) activity, and alters VEGF splicing. We analyzed VEGF isoforms, Wt1, Srpk1, and Srsf1 in normal and tumor endothelium. Wt1, Srpk1, Srsf1, and the angiogenic VEGF164a isoform were highly expressed in tumor endothelium compared to normal lung endothelium. Nuclear expression of Srsf1 was detectable in the endothelium of various tumor types, but not in healthy tissues. Inducible conditional vessel-specific knockout of Wt1 reduced Wt1, Srpk1, and Srsf1 expression in endothelial cells and induced a shift towards the antiangiogenic VEGF120 isoform. Wt1(−KTS) directly binds and activates both the promoters of Srpk1 and Srsf1 in endothelial cells. In conclusion, Wt1 activates Srpk1 and Srsf1 and induces expression of angiogenic VEGF isoforms in tumor endothelium

    Merging Top‐Down and Bottom‐Up Approaches to Fabricate Artificial Photonic Nanomaterials with a Deterministic Electric and Magnetic Response

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    Artificial photonic nanomaterials made from densely packed scatterers are frequently realized either by top-down or bottom-up techniques. While top-down techniques offer unprecedented control over achievable geometries for the scatterers, by trend they suffer from being limited to planar and periodic structures. In contrast, materials fabricated with bottom-up techniques do not suffer from such disadvantages but, unfortunately, they offer only little control on achievable geometries for the scatterers. To overcome these limitations, a nanofabrication strategy is introduced that merges both approaches. A large number of scatterers are fabricated with a tailored optical response by fast character projection electron-beam lithography and are embedded into a membrane. By peeling-off this membrane from the substrate, scrambling, and densifying it, a bulk material comprising densely packed and randomly arranged scatterers is obtained. The fabrication of an isotropic material from these scatterers with a strong electric and magnetic response is demonstrated. The approach of this study unlocks novel opportunities to fabricate nanomaterials with a complex optical response in the bulk but also on top of arbitrarily shaped surfaces

    Materials Pushing the Application Limits of Wire Grid Polarizers further into the Deep Ultraviolet Spectral Range

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    Wire grid polarizers (WGPs), periodic nano-optical meta-surfaces, are convenient polarizing elements for many optical applications. However, they are still inadequate in the deep ultraviolet spectral range. We show that to achieve high performance ultraviolet WGPs a material with large absolute value of the complex permittivity and extinction coefficient at the wavelength of interest has to be utilized. This requirement is compared to refractive index models considering intraband and interband absorption processes. We elucidate why the extinction ratio of metallic WGPs intrinsically humble in the deep ultraviolet, whereas wide bandgap semiconductors are superior material candidates in this spectral range. To demonstrate this, we present the design, fabrication and optical characterization of a titanium dioxide WGP. At a wavelength of 193 nm an unprecedented extinction ratio of 384 and a transmittance of 10 % is achieved.Comment: 21 pages, Advanced Optical Materials 201

    Myocardial-specific R-spondin3 drives proliferation of the coronary stems primarily through the Leucine Rich Repeat G Protein coupled receptor LGR4

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    Coronary artery anomalies are common congenital disorders with serious consequences in adult life. Coronary circulation begins when the coronary stems form connections between the aorta and the developing vascular plexus. We recently identified the WNT signaling modulator R-spondin 3 (Rspo3), as a crucial regulator of coronary stem proliferation. Using expression analysis and tissue-specific deletion we now demonstrate that Rspo3 is primarily produced by cardiomyocytes. Moreover, we have employed CRISPR/Cas9 technology to generate novel Lgr4-null alleles that showed a significant decrease in coronary stem proliferation and thus phenocopied the coronary artery defects seen in Rspo3 mutants. Interestingly, Lgr4 mutants displayed slightly hypomorphic right ventricles, an observation also made after myocardial specific deletion of Rspo3. These results shed new light on the role of Rspo3 in heart development and demonstrate that LGR4 is the principal Rspondin 3 receptor in the heart
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