2,843 research outputs found
Light Meson Dynamics Workshop. Mini proceedings
No full text46 pages, 17 contributions. Editors: W. Gradl, P. Masjuan, M. Ostrick, and S. SchererInternational audienceThe mini-proceedings of the Light Meson Dynamics Workshop held in Mainz from February 10th to 12th, 2014, are presented. The web page of the conference, which contains all talks, can be found at https://indico.cern.ch/event/287442/overview
Light Meson Dynamics Workshop. Mini proceedings
No full text46 pages, 17 contributions. Editors: W. Gradl, P. Masjuan, M. Ostrick, and S. SchererInternational audienceThe mini-proceedings of the Light Meson Dynamics Workshop held in Mainz from February 10th to 12th, 2014, are presented. The web page of the conference, which contains all talks, can be found at https://indico.cern.ch/event/287442/overview
Assessment of the peripheral microcirculation using computer-assisted venous congestion plethysmography in post-traumatic complex regional pain syndrome type I
No full textIn complex regional pain syndrome type I (CRPS-I), edema of the affected limb is a common finding. Therefore, the changes in macro- and microcirculatory parameters were investigated to elucidate the underlying pathophysiology. Twenty-four patients with post-traumatic CRPS-I and 25 gender- and age-matched healthy subjects were examined by means of an advanced computer-assisted venous congestion strain-gauge plethysmograph. The recording of the volume response of the forearm to a stepwise inflation of an occlusion cuff placed at the upper arm enabled the calculation of the arterial blood flow into the arm (Q(a)), the vascular compliance (C), the peripheral venous pressure (P-v), the isovolumetric venous pressure (P-vi; = hydrostatic pressure needed to achieve net fluid filtration) and the capillary filtration capacity (CFC) - an index of microvascular permeability. The study revealed no difference in any of the parameters between the right and left hand of healthy subjects. In CRPS-I patients, however Qs, Pv, Pvi and CFC were significantly (p < 0.01/0.001) elevated in the affected arm (Q(a) 11.2 +/- 7.0 ml min(-1) 100 ml(-1), P-v 20.2 +/- 8.1 mm Hg, P-vi 24.7 +/- 4.2 mm Hg, CFC 0.0058 +/- 0.0015 ml min(-1) 100 ml(-1) mm Hg-1) compared to the unaffected arm (Q(a) 4.2 +/- 2.4 ml min(-1) 100 ml(-1), P-v 10.0 +/- 5.1 mm Hg, P-vi 13.2 +/- 3.7 mm Hg, CFC 0.0038 +/- 0.0005 ml min(-1) 100 ml(-1) mm Hg-1) and the values obtained in healthy controls (Q(a) 5.1 +/- 1.3 ml min(-1) 100 ml(-1), P-v 10.4 +/- 4.3 mm Hg, P-vi 15.7 +/- 3.3 mm Hg, CFC 0.0048 +/- 0.0012 ml min(-1) 100 ml(-1) mm Hg-1). Whereas the values in the unaffected arm of CRPS-I patients revealed no difference in Q(a), P-v and P-vi but a lower CFC (p < 0.01) compared to those from healthy controls. These results suggest profound changes in both macro- and microvascular perfusion in the affected arm of CRPS-I patients. The high CFC contributes to the edema formation, and combined with the elevated Pvi, they are in agreement with the hypothesis of an inflammatory origin of CRPS. Copyright (C) 2001 S. Karger AG, Basel
In vivo x-ray imaging of the respiratory system using synchrotron sources and a compact light source.
No full textBright synchrotron x-ray sources enable imaging with short exposure times, and hence in a high-speed image sequence. These x-ray movies can capture not only sample structure, but also how the sample changes with time, how it functions. The use of a synchrotron x-ray source also provides high spatial coherence, which facilitates the capture of not only a conventional attenuation-based x-ray image, but also phase-contrast and dark-field signals. These signals are strongest from air/tissue interfaces, which means that they are particularly useful for examining the respiratory system. We have performed a range of x-ray imaging studies that look at lung function, airway surface function, inhaled and instilled treatment delivery, and treatment effect in live small animal models [Morgan, 2019]. These have utilized a range of optical set-ups and phase-contrast imaging methods in order to be sensitive to the relevant sample features, and be compatible with high-speed imaging. For example, we have used a grating interferometer to measure how the airsacs in the lung inflate during inhalation, via changes in the dark-field signal [Gradl, 2018], a single-exposure, single-grid set-up to capture changes in the liquid lining of the airways [Morgan, 2015] and propagation-based phase contrast to image clearance of inhaled debris [Donnelley, 2019]. Studies have also utilized a range of analysis methods to extract how the sample features change within a time-sequence of two-dimensional projections or three-dimensional volumes. While these imaging studies began in large-scale synchrotron facilities, we have recently performed these kinds of studies at an inverse-Compton-based compact synchrotron, the Munich Compact Light Source (MuCLS) [Gradl, 2018b]. 1. Morgan, Kaye, et al., "Methods for dynamic synchrotron X-ray imaging of live animals.", under review 01/2019. 2. Gradl, R., et al. "Dynamic in vivo chest x-ray dark-field imaging in mice." IEEE Transactions on Medical Imaging (2018). 3. Morgan, Kaye S., et al. "In vivo X-ray imaging reveals improved airway surface hydration after a therapy designed for cystic fibrosis." American Journal of Respiratory and Critical Care Medicine 190.4 (2014): 469-472. 4. Donnelley, Martin, et al. "Live-pig-airway surface imaging and whole-pig CT at the Australian Synchrotron Imaging and Medical Beamline." Journal of Synchrotron Radiation 26.1 (2019). 5. Gradl, Regine, et al. "In vivo Dynamic Phase-Contrast X-ray Imaging using a Compact Light Source." Scientific Reports 8.1 (2018b): 6788
Metal additive manufacturing in aerospace: a review
No full textMetal additive manufacturing involves manufacturing techniques that add material to produce metallic components, typically layer by layer. The substantial growth in this technology is partly driven by its opportunity for commercial and performance benefits in the aerospace industry. The fundamental opportunities for metal additive manufacturing in aerospace applications include: significant cost and lead-time reductions, novel materials and unique design solutions, mass reduction of components through highly efficient and lightweight designs, and consolidation of multiple components for performance enhancement or risk management, e.g. through internal cooling features in thermally loaded components or by eliminating traditional joining processes. These opportunities are being commercially applied in a range of high-profile aerospace applications including liquid-fuel rocket engines, propellant tanks, satellite components, heat exchangers, turbomachinery, valves, and sustainment of legacy systems. This paper provides a comprehensive review of metal additive manufacturing in the aerospace industry (from industrial/popular as well as technical literature). This provides a current state of the art, while also summarizing the primary application scenarios and the associated commercial and technical benefits of additive manufacturing in these applications. Based on these observations, challenges and potential opportunities are highlighted for metal additive manufacturing for each application scenario. © 2021 The Author(s
Wnt 5a signaling is critical for macrophage-induced invasion of breast cancer cell lines
No full textInteractions between neoplastic and stromal cells contribute to tumor progression. Wnt genes, involved in cell migration and often deregulated in cancers, are attractive candidates to regulate these effects. We have recently shown that coculture of breast cancer cells with macrophages enhances invasiveness via matrix metal loproteases and TNF-alpha. Here we demonstrate that coculture of MCF-7 cells and macrophages leads to up-regulation of Writ 5a in the latter. This was accompanied by activation of AP-1/c-Jun in MCF-7. Recombinant Writ 5a mimicked the coculture effect. Writ 5a was also detectable in tumor-associated macrophages in primary breast cancers. Experiments with agonists and antagonists of Writ signaling revealed that a functional canonical pathway in the tumor cells was a necessary prerequisite; however, noncanonical signaling via Writ 5a and the Jun-N-terminal kinase pathway was critical for invasiveness. It was also responsible for induction of matrix metalloprotease-7, known to release TNF-alpha. All these effects could be antagonized by dickkopf-1. Our results indicate that Wnt 5a is essential for macrophage-induced invasiveness, because it regulates tumor cell migration as well as proteolytic activity of the macrophages. The function of Writ 5a as either a suppressor or promoter of malignant progression seems to be modulated by intercellular interactions. Writ 5a detection in tumor-associated macrophages in breast cancer biopsies supports the assumption that similar events play a role in vivo.Medical Research Council [G0601867
Future solar home systems: Matching energy supply with energy demand
No full text1.3 billion people in the world lack access to electricity (International Energy Agency (2013). The largest share of this group is poor and lives in the developing world, and has to deal with unmet basic needs. Having the possibility to use reliable and clean energy is seen as a driver for social development and environmental sustainability. Having access to energy is also often linked to economic growth and has a positive impact on health. (Gradl & Knobloch, 2011) Improving energy access is therefore a hot topic worldwide. With a Solar Home System (SHS), energy can be generated and used on a household level at places where the electric grid does not reach. The main components of a SHS are a solar panel for the generation of electricity, a battery for energy storage and balance of system (BoS) components, including power electronics, to coordinate the flows of energy. SHS are offered by multiple companies worldwide, and come in various configurations. The smallest SHS are capable of powering for example LED lights, phones and/or a radio, while larger SHS can power for example televisions and fans. Generally speaking, SHSs are increasing in size. This is due to dropping prices of system components. Where in 2003 a SHS of 20 Wp was economically competitive with kerosene lamps, in 2015 this was already 70-80 Wp. (Chattopadhyay, Bazilian and Peter Lilienthal, 2015) The conventional technologies are likely to dominate the SHS the upcoming years. Proven technologies are favourable as reliability is key for SHSs. This means that most of the SHSs in the future will rely on crystalline silicon panels and lead-acid batteries. In the future, li-ion battery technologies will become competitive as prices are dropping...Integrated Product Desig
Integral Channel Nozzles and Heat Exchangers using Additive Manufacturing Directed Energy Deposition NASA HR-1 Alloy
No full textHeat exchangers for use in propulsion applications are very critical components because they must be efficient, compact and light and often operate with working fluids at extreme temperatures or pressures or both. Various components and systems use heat exchangers such as combustion chambers of gas turbines and internal combustion engines, fuel cells (air supply and thermal management), electric batteries (thermal management), evaporators and recuperators of waste-heat-to-power systems, and rocket engines. Even if the results are more generally applicable, the heat exchangers applications to which this study is more closely related are regeneratively cooled rocket nozzles and chambers, and repressurization systems for the launch vehicles. These components are often thin-walled and contain pressurized fluids, like propellants at cryogenic or elevated temperatures. Given that the environments that these propulsion components must endure are challenging, the manufacturing to meet these specifications often require long lead times due to specialty processes and unique tooling associated with the combined thin-wall integral channel and large-scale structures. Additive manufacturing (AM) offers programmatic advantages for reduction in processing time and cost in addition to various technical advantages, including the possibility to achieve enhanced hardware complexity targeted to superior performance, part consolidation, and the capability of processing of novel alloys. While AM is already being utilized for heat exchanger components in propulsion applications, almost all these AM components are made by means of Laser Powder Bed Fusion (L-PBF). L-PBF allows for fine features but is rather limited with respect to the overall size of the components that can be manufactured. Recent developments are maturing the Laser Powder Directed Energy Deposition (LP-DED) process which may be used, for example, to make integral channel thin-wall regeneratively-cooled rocket nozzles with diameters greater than 1 m. This paper highlights some integral channel heat exchanger demonstrator hardware applications of LP-DED, as well as the characterization of this process in combination with the use of the NASA HR-1 alloy. To properly utilize LP-DED for heat exchanger manufacturing, various aspects are being characterized such as geometry limitations, measurement of surface texture and geometric angled surfaces, surface enhancements for internal channels, and material evaluation. NASA HR-1 (Fe-Ni-Cr) is a high strength hydrogen resistant superalloy developed for use in aerospace applications, such as heat exchangers. Some aspects and considerations about the design of heat exchangers are summarized together with data relevant to LP-DED manufacturing in combination with the NASA HR-1 alloy. Microchannels were successful deposited down to 2.54 mm and 1 mm wall thickness, wall angles of 30°, both with high reproducibility. It was also found that the areal surface roughness is highly dependent on the size of the powder feedstock used for deposition. The characterization of these LP-DED features is critical for fluid flow and heat transfer predictions as it can be exploited to enhance heat transfer at the cost of increased pressure drop.Space Systems EgineeringFlight Performance and Propulsio
Rediscovering the double Friedel-Crafts acylation : an expedient entry to phenanthrene-9,10-diones
No full textThe double Friedel–Crafts acylation of readily accessible biaryls with oxalyl chloride delivers the respective phenanthrene-9,10-diones, providing an alternative to the traditional methods, which require harsh oxidizing conditions and multistep sequences. This simple method allows the synthesis of various symmetrical and non-symmetrical targets, and is even effective for the synthesis of the parent ring system from (unactivated) biphenyl
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