633 research outputs found

    Fragility and compressibility at the glass transition

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    Isothermal compressibilities and Brillouin sound velocities from the literature allow to separate the compressibility at the glass transition into a high-frequency vibrational and a low-frequency relaxational part. Their ratio shows the linear fragility relation discovered by x-ray Brillouin scattering [1], though the data bend away from the line at higher fragilities. Using the concept of constrained degrees of freedom, one can show that the vibrational part follows the fragility-independent Lindemann criterion; the fragility dependence seems to stem from the relaxational part. The physical meaning of this finding is discussed. [1] T. Scopigno, G. Ruocco, F. Sette and G. Monaco, Science 302, 849 (2003)Comment: 4 pages, 2 figures, 2 tables, 33 references. Slightly changed after refereein

    IV-VI resonant cavity enhanced photodetectors for the midinfrared

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    A resonant-cavity enhanced detector operating in the mid-infrared at a wavelength around 3.6 micron is demonstrated. The device is based on a narrow-gap lead salt heterostructure grown by molecular beam epitaxy. Below 140 K, the photovoltage clearly shows a single narrow cavity resonance, with a relative line width of only 2 % at 80 K.Comment: 2 figure

    Three-Dimensional Modeling of Glucose-6-phosphate Dehydrogenase-Deficient Variants from German Ancestry

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    Loss of function of dimeric glucose-6-phosphate dehydrogenase (G6PD) represents the most common inborn error of metabolism throughout the world affecting an estimated 400 million people. In Germany, this enzymopathy is very rare. units. Three mutations, i.e. G6PD Munich, G6PD Riverside and G6PD Gastonia, lie closer to the interface of the two monomers. These may also affect the interface of two monomers.None of these G6PD variants share mutations with the common G6PD variants known from the Mediterranean, Near East, or Africa indicating that they have developed independently. The G6PD variants have been compared with mutants from other populations and the implications for survival of G6PD variants from natural selection have been discussed

    The Dramatic End. The Last Things and the End of the World in the theology of Hans Urs von Balthasar

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    \u27Gericht\u27 und Weltende scheinen heute vielfach in den Hintergrund theologischer Rede und kirchlicher Verkundigung geraten zu sein. Oft wird and die Gerichtsverkundigung und die Sundentheologie der Vergangenheit gedacht. Da verwundert es nicht, dass viele Menschen sich heute scheuen von Gericht zu sprechen. In den vergangenen Jahrzehnten hat sich in der Gesellschaft aber auch ein anderer Trend entwickelt, bei dem in Gegensatz zur Zuruckhaltung in der Gerichtsthematik endzeitliche Vorstellungen die Menschen fasziniert. Das Papier ist Diskussion ĂŒber die letzten Dinge und das Ende der Welt in der Theologie von Hans Urs von BalthasarJudgment and the end of the world today often appear in the background of the discussions about theological and ecclesiastical proclamation. It is often related to the thoughts about justice and theology of sins, therefore many people are afraid to speak about these issues. However, in the last decade a different trend has been developed and quite opposite eschatological ideas started to fascinate people. This paper discusses the Last Things and the End of the World in the aspect of dramatic theory of Hans Urs von Balthasar\u27s theology

    Evaluation of an indoor localization system for a mobile robot

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    Although indoor localization has been a wide researched topic, obtained results may not fit the requirements that some domains need. Most approaches are not able to precisely localize a fast moving object even with a complex installation, which makes their implementation in the automated driving domain complicated. In this publication, common technologies were analyzed and a commercial product, called Marvelmind Indoor GPS, was chosen for our use case in which both ultrasound and radio frequency communications are used. The evaluation is given in a first moment on small indoor scenarios with static and moving objects. Further tests were done on wider areas, where the system is integrated within our Robotics Operating System (ROS)-based self-developed 'Smart PhysIcal Demonstration and evaluation Robot (SPIDER)' and the results of these outdoor tests are compared with the obtained localization by the installed GPS on the robot. Finally, the next steps to improve the results in further developments are discussed

    Mysticism or experimental dogmatics – Adrienne von Speyr as a challenge and an opportunity for dogmatics

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    Innerhalb der christlichen Mystik lassen sich seit ihren AnfĂ€ngen zahlreiche Beispiele fĂŒr ekstatische Erfahrungen finden. Auch im 20. Jahrhundert ist die Ekstase als PhĂ€nomen im christlichen Kontext noch prĂ€sent. Allerdings gerĂ€t eine ekstatische Mystik nicht nur von gesellschaftlicher Seite aus unter Kritik, sondern auch innerhalb der Kirche und der Theologie scheint eine Akzeptanz ekstatischer PhĂ€nomene zunehmend schwierig zu sein. Diese Problematik veranschaulicht uns das Beispiel der Schweizer Mystikerin Adrienne von Speyr. Ihre Zusammenarbeit mit dem Priester und Theologen Hans Urs von Balthasar, lĂ€sst beide in ein gesellschaftliches und kirchliches Abseits geraten. Ihr gemeinsames Werk, das unter dem Begriff ‚experimentelle Dogmatik‘ zusammengefasst werden kann, kann allerdings auch heute noch fĂŒr die Theologie fruchtbar sein und wesentliche Inputs vermitteln. So ergeben sich am Beispiel Adrienne von Speyrs Fragen zu Akzeptanz und Relevanz ekstatischer Mystik.The conceptual relation between mysticism and ecstasy has a long tradition in Christian religion. But the recognition of ecstatic-mystical experiences in the 20th and the 21th century seems to get difficult. Since the Enlightenment mysticism and ecstasy get more and more beyond a scientific understanding in theology. This leads to the question: Could there be a place for mysticism and ecstasy in dogmatics? We will find a possible answer in the story of the Swiss mystic Adrienne von Speyr. Together with the work of the priest and theologian Hans Urs von Balthasar, Adrienne von Speyrs mysticism could be described as an experimental dogmatics. Her visions, auditions and other ecstatic phenomena brought back many old and lost contents in theology. But her working relationship with Hans Urs von Balthasar raises even today a lot of questions

    Hydration effects turn a highly stretched polymer from an entropic into an energetic spring

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    Polyethylene glycol (PEG) is a structurally simple and nontoxic water-soluble polymer that is widely used in medical and pharmaceutical applications as molecular linker and spacer. In such applications, PEG’s elastic response against conformational deformations is key to its function. According to text-book knowledge, a polymer reacts to the stretching of its end-to-end separation by a decrease in entropy that is due to the reduction of available conformations, which is why polymers are commonly called entropic springs. By a combination of single-molecule force spectroscopy experiments with molecular dynamics simulations in explicit water, we show that entropic hydration effects almost exactly compensate the chain conformational entropy loss at high stretching. Our simulations reveal that this entropic compensation is due to the stretching-induced release of water molecules that in the relaxed state form double hydrogen bonds with PEG. As a consequence, the stretching response of PEG is predominantly of energetic, not of entropic, origin at high forces and caused by hydration effects, while PEG backbone deformations only play a minor role. These findings demonstrate the importance of hydration for the mechanics of macromolecules and constitute a case example that sheds light on the antagonistic interplay of conformational and hydration degrees of freedom

    Optimizing the parameters for hydro-jet dissection in fatty tissue — A morphological Ex Vivo analysis

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    Summary: Background: The advantage of water-jet dissection is the preservation of vessels and nerves. Especially in liver surgery, blood loss can be significantly decreased. The use of water-jet dissectors in other fields of surgery is currently under investigation. The preparation of vessels in fatty tissue is of special interest for plastic surgeons. The optimal technical parameters were investigated. Methods: Abdominal fat tissue of fresh cadavers was cut under standardized conditions with different parameters of the water-jet dissector. Results: One single pass at a cutting pressure between 20 and 60 Bar makes an incision of 8 mm. Deeper cuts can be achieved by repeated application on the same cut. Five passes at 40 Bar results in a depth of 1.7 cm without vessel damage. If the applied pressure is 50 or 60 Bar, up to 7% damaged vessels can be found. The water-jet dissection leads to a water uptake of the cut tissue. Conclusions: The optimal pressure for water-jet dissection of fatty tissue lies between 30 and 40 Bar. The effect of the mechanical irritation of the vessels has to be investigatedin vivo before using the water-jet dissector for preparation of blood vessels in humans, e.g. for flap dissectio

    General method for the quantification of drug loading and release kinetics of nanocarriers

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    Macromolecular nanostructures that are used as drug carriers are characterized by their loading and release kinetics. Release studies commonly employ the dialysis method, in which a cellulose membrane separates the solution of released drug from the nanocarrier solution. We demonstrate that it is necessary to take the effect of the dialysis membrane on the release kinetics into account. Using a two-step approach, consisting of a calibration experiment of drug diffusion through the dialysis membrane in the absence of nanocarriers, and an experiment in the presence of nanocarriers, we are able to determine all kinetic rates and in particular to disentangle kinetic dialysis membrane properties from kinetic nanocarrier properties. We apply our general approach to experimental dexamethasone release data from core-multishell nanocarriers and demonstrate that our method yields a consistent description of the nanocarrier release kinetics
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