2,949 research outputs found
Lung CT imaging in patients with bronchopulmonary dysplasia: A systematic review
No full textBackgroundBronchopulmonary dysplasia (BPD) is a common respiratory complication of preterm birth and associated with long-term respiratory sequelae. Chest computed tomography (CT) is a sensitive tool to obtain insight in structural lung abnormalities and may be a predictor for later symptoms. ObjectivesTo give an overview of chest CT scoring methods that are used to evaluate chest CT scans of BPD patients. To review which structural lung abnormalities are described in children and adults with BPD and whether these are related to clinical outcomes. MethodsAn extensive literature search was conducted for relevant studies on chest CT imaging in patients born preterm with BPD. ResultsWe retrieved 316 original papers of which 16 articles and three abstracts fulfilled our inclusion criteria. Overall, we identified nine different semi-quantitative scoring methods. Chest CT scans revealed structural abnormalities in >85% of BPD patients. These abnormalities are decreased pulmonary attenuation, opacities, bronchial wall thickening, and consolidations. Some have been found to be negatively correlated with lung function and respiratory symptoms. ConclusionsNone of the currently described scoring systems are appropriately validated or superior over another. Future studies are needed to generate a validated and universal chest CT quantitative scoring method for patients with BPD. Pediatr Pulmonol. 2016; 51:975-986
Exhaled nitric oxide in mylar balloons: influence of storage time, humidity and temperature
No full textBackground: Mylar balloons are used to collect exhaled air for analysis of fractional nitric oxide concentration (FENO)
Paediatrics in Berlin
No full textThe aim of this report is to describe the highlights of the European Respiratory Society annual congress in Berlin, Germany. The best abstracts in asthma and allergy, cystic fibrosis, respiratory infection, paediatric and neonatal intensive care, paediatric investigative techniques (in particular respiratory physiology and bronchoscopy) and respiratory epidemiology are presented and set in the context of the current literature. Copyrigh
Measurements of exhaled nitric oxide in healthy subjects age 4 to 17 years
No full textBACKGROUND:
Fractional exhaled nitric oxide (FE NO ) is used in monitoring of asthma.
OBJECTIVES:
The aim of this multicenter study was to establish normal values of FE NO and assess feasibility in children with a standardized method and equipment approved for clinical use.
METHODS:
FE NO was measured in healthy subjects of 4 to 17 years according to American Thoracic Society guidelines (single breath online, exhalation flow 50 mL/s) with a chemiluminescence analyzer (NIOX Exhaled Nitric Oxide Monitoring System, Aerocrine, Sweden) in 3 European and 2 US centers. Each child performed 3 acceptable nitric oxide measurements within 6 attempts and completed an extended International Study of Asthma and Allergy in Children questionnaire.
RESULTS:
Measurement of FE NO was attempted in 522 children. Four hundred five children completed the study according to the protocol. Geometric mean FE NO in 405 children was 9.7 ppb, and the upper 95% confidence limit was 25.2 ppb. FE NO increased significantly with age, and higher FE NO was seen in children with self-reported rhinitis/conjunctivitis or hay fever. The success rate was age-dependent and improved from 40% in the children 4 years old to almost 100% from the age of 10 years. The repeatability of 3 approved measurements was 1.6 ppb (95% CI, 1.49-1.64 ppb).
CONCLUSION:
FE NO in healthy children is below 15 to 25 ppb depending on age and self-reported atopy. Measurement of FE NO by NIOX is simple and safe and has a good repeatability. Feasibility depends on age and may be difficult in the preschool child
Comparative feasibility study of a 30 MW disruptive floater solution with a 15 MW PivotBuoy and a benchmark 15 MW semi-submersible floater in the Bay of Biscay
No full textThis paper investigates the technical, life cycle, and economic feasibility of a 30 MW upscaled downwind turbine, comparing it to a 15 MW X1 Wind PivotBuoy downwind turbine and a benchmark 15 MW IEA Umaine VolturnUS-S upwind turbine in the 450 MW Sud de la Bretagne I wind farm site. The study is significant due to the rising energy demand, the potential for decreasing the levelized cost of energy with increased turbine size, and the optimized use of space. The size limit of current upwind turbine designs could be addressed using a downwind turbine solution.The research is conducted by modelling the global dynamic response of the structure using OpenFAST and computing the natural frequencies and stresses using a finite element model. A lifecycle analysis is performed to identify potential pitfalls and bottlenecks by analysing the individual lifecycle phases. The economic feasibility is assessed by simulating the annual energy production using TOPFARM and utilizing structural analysis and lifecycle assessment to quantify capital, operational, and abandonment expenditures. Based on the annual energy production and the performance indicators the levelized cost of energy is calculated.The findings indicate that while the global stability is within boundaries, the stress in members is too high with a simple scale-up of the proposed design. Bottlenecks are found in lifting operations and supply chain readiness. The levelized cost of energy and capital expenditure increased due to substructure self-weight, rendering the proposed 30 MW scale-up currently unfeasible when compared to the other two wind farms.These findings are important as they demonstrate that the 15 MW X1 Wind PivotBuoy is not scalable without design changes. The levelized cost of energy does not decrease with an increased floater solution. The 15 MW X1 Wind PivotBuoy downwind turbine seems more economically viable, making it a more interesting option for future development.Civil Engineerin
Short-circuit characteristics of superconducting permanent magnet generators for 10 MW wind turbines
No full textSuperconducting permanent magnet generators (SCPMGs) are a potential candidate for 10 MW direct-drive wind turbine applications. This paper presents two 10 MW SCPMG designs using MgB<sub>2</sub> cables for the armature winding and investigates the short-circuit characteristics of the designed SCPMGs. The first part of the results shows that the SCPMGs can double the shear stress of a conventional low-speed permanent magnet (PM) generator (from 65 kPa to 130 kPa) whilst avoiding demagnetization of the PMs in rated-load operation. However, the power factor has to drop to a range of 0.7-0.8. The second part of the results shows that during a sudden three-phase short circuit, the superconducting armature winding is prone to quench and the PMs are likely to be demagnetized in both proposed designs.Accepted Author ManuscriptTransport Engineering and Logistic
An Ultrasonically Powered System Using an AlN PMUT Receiver for Delivering Instantaneous mW-Range DC Power to Biomedical Implants
No full textAluminum Nitride (AlN) Piezoelectric Micromachined Ultrasonic Transducers (PMUTs) are gaining interest for biomedical implant power due to biocompatibility and lowtemperature processing. However, due to the low piezoelectric coefficient of AlN PMUTs, storage capacitors are often used to accumulate ultrasonic power transferred over an extended time. The accumulated energy is then used to power a DC load, which leads to a long start-up time, and insufficient duty cycle for some applications. We present an ultrasonically powered system for biomedical implants capable of delivering mW-range instantaneous power to DC loads, without pre-storing it. The system features a 25 mm2 AlN PMUT, an inductive matching network, and an application-specific power management integrated circuit(ASIC). For an acoustic intensity of 360 mW/cm2 at the surface of the PMUT, an open-circuit voltage of 1.11 V and an aperture efficiency of 30.5 % are measured. Furthermore, by connecting a series-matching inductor to the PMUT, the highest-reported power delivered to the load (PDL) of 6.4 mW is measured over an optimal load of 7.6 Ω. Finally, together with the ASIC and at the intensity of 108 mW/cm2, our system delivers 1.04 mW DC power to a 3.3 kΩ load, which is over two orders of magnitude higher than the previously reported average DC power for AlN PMUTs.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Bio-ElectronicsElectronic Components, Technology and Material
Clinical and cost effectiveness of mechanical support for severe ankle sprains : design of a randomised controlled trial in the emergency department [ISRCTN 37807450]
No full textBackground
The optimal management for severe sprains (Grades II and III) of the lateral ligament complex of the ankle is unclear. The aims of this randomised controlled trial are to estimate (1) the clinical effectiveness of three methods of providing mechanical support to the ankle (below knee cast, Aircast® brace and Bledsoe® boot) in comparison to Tubigrip®, and (2) to compare the cost of each strategy, including subsequent health care costs.
Methods/design
Six hundred and fifty people with a diagnosis of severe sprain are being identified through emergency departments. The study has been designed to complement routine practice in the emergency setting. Outcomes are recovery of mobility (primary outcome) and usual activity, residual symptoms and need for further medical, rehabilitation or surgical treatment. Parallel economic and qualitative studies are being conducted to aid interpretation of the results and to evaluate the cost-effectiveness of the interventions.
Discussion
This paper highlights the design, methods and operational aspects of a clinical trial of acute injury management in the emergency department
Inversion of coseismic deformation due to the 8th February 2016, Mw 4.2 earthquake at Los Humeros (Mexico) inferred from DInSAR
No full textOn the 8th of February 2016, a Mw 4.2 earthquake was detected inside the Los Humeros caldera, located in the eastern sector of the Trans-Mexican Volcanic Belt. The event occurred after a sharp increase in the injection rate at the Los Humeros Geothermal Field and it was recorded by the seismic monitoring network of the power plant. The earthquake was felt by the local population and it caused damage in the power plant infrastructure. The focal mechanism solution of a previous study based on seismological data shows a reverse movement with a minor left-lateral component: Mw=4.2, depth=1500m, strike=169°, dip=61°, rake=42°. We have performed a geodetic and geomechanical analysis of the seismic source event based on ground deformation inferred from DInSAR. We used ascending and descending Sentinel-1 differential interferograms to retrieve the horizontal and vertical components of the co-seismic deformation. Subsequently, we inverted the estimated deformation to obtain the solution of an activated fault using the Okada model. These results shed light on the geomechanical aspects of the event and can help to understand the effects of field operations interacting with pre-existing structural features and active tectonic processes in the Los Humeros caldera.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Mathematical Geodesy and Positionin
Towards a True Author Entry System for CAI
No full textCAI course authors have been faced with the disc tint problem of having to learn an instructional coding language before they can get their courses into the computer. A system has been devised so that an author may easily write his course in English on course planning forms and then a pre-processor will generate the coding which will be input for the machine assembler
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