1,350 research outputs found
The effects of activated eosinophils and neutrophils on guinea pig airway epithelium in vitro
No full textEpithelial shedding is a characteristic feature of asthmatic airways and has been attributed to eosinophil products. We have examined the interaction of purified intraperitoneal guinea pig eosinophils with or without platelet-activating factor (PAF, 10(-7) M) or lyso-PAF (10(-7) M) with guinea pig tracheal epithelium in vitro. At 0, 4, 14, and 24 h, the percentage of ciliation of the tracheal circumference (CTC) was measured by light microscopy and the ciliary beat frequency (CBF) by photometry. PAF-activated eosinophils (50 x 10(6) cells/ml) disrupted the epithelium, mean CBF and CTC being reduced by 77.8 +/- 5.8% (mean +/- SEM; P less than 0.001 versus control) and 94.2 +/- 1.4% (P less than 0.001) over 24 h, respectively. PAF (10(-7) M) alone had no significant effect. Lyso-PAF with eosinophils (50 x 10(6) cells/ml) also reduced mean CBF and CTC but to a lesser extent. Eosinophils alone also led to a reduction of 36.2 +/- 11.4% in mean CBF and 53.0 +/- 15.5% in CTC, but these changes were not significant. The PAF antagonist, WEB 2086 (10(-6) M), significantly inhibited the mean CBF and CTC reduction due to PAF-activated eosinophils by 61.5 +/- 17.2% (P less than 0.01) and 20.8 +/- 6.5% (P less than 0.05), respectively. In addition, catalase (1,125 U/ml) partially inhibited the mean CBF and CTC reduction induced by PAF-activated eosinophils. Intraperitoneal neutrophils (PMN) (50 x 10(6) cells/ml) also disrupted epithelium but to a lesser extent (24-h reduction: 34.2 +/- 12.7% for mean CBF and 60.2 +/- 13.2% for CTC, respectively). Stimulation with PAF (10(-7) M) had no further effect. Marked exfoliation of the epithelial layer was observed after 14 h of incubation with activated eosinophils. We concluded the PAF-activated eosinophils are capable of grossly disrupting ciliated epithelium and may contribute to epithelial damage observed in asthma.</p
Cathodoluminescence readout of high-density nanoparticle phase change memory
No full textFor the first time we demonstrate that information can be written in the structural phase of gallium nanoparticles within an array by a focused electron beam and read-out via measurements of cathodoluminescent emission
Nanoparticle optical memory function
No full textLight and electron-beam induced structural transformations in nanoparticles of polymorphic metals provide a paradigm for achieving resonator-less optical memory functionality with picojoule energy requirements. We demonstrate optical memory function with gallium nanoparticles grown by light-assisted self-assembly at the end face of an optical fiber and show how a nanoparticle can constitute an optical memory bit which can be read and erased by a weak probe beam, and written by a single optical control pulse
Niet zonder conflicten
No full textDuurzame ontwikkeling in het ingenieursonderwijs blijkt geen snelle conflictloze strategie voor verduurzaming. Met als gevolg dat het breder leren denken van de ingenieur in opleiding nog in de kinderschoenen staat.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.Organisation & Governanc
Pretexts for writing: German prefaces around 1800
No full textThroughout history, there have been playful prefaces to literature (or in classical oratory, before display pieces). But German examples written by authors around 1800 to their own works, together with contemporary, self-authored prefaces to speculative philosophy, constitute a peculiarly paradoxical text type. Once literature was conceived as an autonomous domain rather than as a branch of general learning; as a popular book market took hold; and once systematic philosophy competed with literature’s broad acclaim as well as intellectual independence, the preface became not only a pragmatic, but also a creative and conceptual problem. Hence the preface became complicated as a form, in a broadly Romantic tradition of thought in which every act of genuine reflection was understood to expose epistemological contradiction. After my general, theoretical Preface and my comparative, historical Introduction, I focus on three preface paradoxes and three case studies of remarkably complex textuality: on Goethe, Jean Paul and Hegel. Most notable among their prefatory texts are the prefaces to Werther (1774), to a fictive second edition of Quintus Fixlein (1797) and to Phänomenologie des Geistes (1807). This trajectory is a story that begins with literary creativity and moves towards greater philosophical intricacy. The significance of my study is threefold. First and foremost, considering prefaces in this period of German literature and philosophy complements and augments the negative, subjective Early German Romantic idea of irony, Romantic textual fragmentation, as well as Jean Paul’s and Hegel’s literary and philosophically informed attempts to render both concepts and their manifestation on the page more positive and objective. Fragments are conventionally conceived as additive pieces, fortifying or undermining works. This conception can hold true for prefaces, including those by Goethe, Jean Paul and Hegel. At the end of the eighteenth and the beginning of the nineteenth century, though, a number of writers of fragments argued that their works should be understood as wholes. Precisely some prefaces by Goethe, Jean Paul and Hegel can be read so paradoxically: as unifying, wholesome (in a Sentimental sense) and systematic fragments respectively. Second and third, I show the wider importance of the German preface at the turn of the nineteenth century. Authors around 1800 not only displayed, but discovered and debated a prefatory paradoxicality that we encounter in post-Romantic, post-Structuralist and post-modern literature, theory and philosophy, too. Moreover, I demonstrate the ways in which prefaces by particularly Jean Paul and Hegel influenced especially Kierkegaard, Heidegger and Derrida
Characterization of production in different branches of production in different branches spanish industrial activity, by means of time series analysis.
No full textThis work presents a quantitative study of the evolution of spanish industrial activity, measured by the indices of industrial production, by means of Time Series analysis. Univariate ARIMA models with intervention analysis for all the series of these indices have been constructed. The use of Univariate Time Series models to characterise economic phenomena is justified and the type of characterisation made for each industrial branch is described. The procedures for automatic modelling of series are presented. Then the characteristics of the Spanish industrial branches are shown. These results are collected in a diskette for use of researchers.ARIMA model; Intervention analysis; Univariate model; Industrial production; automatic modelling;
A decade of ERS satellite orbits and altimetry
No full textThe First European Remote Sensing Satellite, ERS-1, was launched in July 1991, fol- lowed by ERS-2 in April 1995. Both satellites carry a radar altimeter to serve oper- ational applications and scientific research in the fields of geodesy, oceanography, glaciology and meteorology. Together, the satellites have now been operating for over twelve years. This thesis embarks on the a voyage along several milestones in the lifetime of these satellites, and particularly of its altimeters. Both altimeter missions were hampered by a number of misfortunes, ranging from hardware failures, via design mishaps, to a sub-optimally designed ground segment. Yet, the altimeter data, when properly processed and supplied with a precise orbit, can compete favourably with data supplied by specialised altimeter satellites like TOPEX/Poseidon and Jason-1. The upgrading of all altimeter cor- rections and the tweaking of the basic altimeter measurements of range, significant wave height and backscatter coefficient, are essential steps in this process, outlined in this thesis. Having accomplished that, the ERS altimeters allow the monitor- ing of annual, semi-annual and secular changes in sea level, which are important factors in study of climate change. A key role in the processing of altimeter data plays the position of the satellite, and its progress in time, the satellite orbit. The quality of the recovered sea surface height is limited by the precision at which the orbit can be determined. A long journey along several stepwise improvements of the orbit determination process, both in the technique as well as in the modelling, have resulted in the reduction of the orbit error by a factor of 30! A major player in this process was the estab- lishment of a gravity field model tailored to the ERS satellites that, when applied to ERS orbit determination, outperformed any of the previous and contemporary general-purpose models. Yet, it is shown that this model, DGM-E04, is not just a fabrication for the benefit of ERS only, but is equally suitable for the orbit determ- ination of TOPEX/Poseidon and as a long-wavelength geoid model. The calibration of the ERS-1 altimeter in 1991 required, at a time when the orbit errors were still counted in decimetres, if not metres, a short-arc orbit determin- ation technique centred over the calibration site off the coast of Venice. Again, through elaborate surveying, gathering of altimeter corrections and tide gauge measurements, problem solving and elimination of errors, a final absolute range bias of 41.5 cm was established, a value that is still within the error margins of more recent estimates. A timing error in the ERS altimeter data was discovered in 1995 and its cause remained a mystery ever since, especially when the timing error appeared to ex- hibit daily, annual and inter-annual variations as well. Although the exact cause may never be found, the issue is examined in fine detail and a model is constructed to eliminate the timing error for the benefit of the quality of the altimeter data.Aerospace Engineerin
Semi-analytical long-arc satellite orbit computation and the estimation of time-varying gravity parameters
No full textAerospace Engineerin
Creating Circular, Efficient and Symbiotic Cities: And How Higher Education Should Contribute to Create the Solutions that are Required
No full textThe ‘Grand Challenges’ of our times, like climate change, resource depletion, global inequity and the destruction of wildlife and biodiversity can only be addressed by innovating cities. This paper will analyse major options for innovating cities, main barriers for these innovations that are rooted in the paradigms of the experts running urban systems and educational reforms that might contribute overcoming these barriers.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.Organisation & Governanc
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