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Search Results: 1 - 10 of 3620 matches for " Gerhard Fritz "
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Iglesia de la Santísima Trinidad en Viena-Austria
Gerhard Mayr, Fritz
Informes de la Construccion , 1979,
Abstract: The profession of the designer of the Holy Trinity Church is clearly reflected n this work, one of the most interesting Austrian religious buildings. His Sculptor trade does not impose on him any technical or social condition, but rather, affords him the necessary freedom to search for religious feeling through the most varied means and media. Thus, using 152 blocks of different sizes and shapes, he constructs a diversified sculptoric volume where the parochial facilities and the church proper are housed. These blocks, alternating with glazed surfaces, help to create inside a feeling of quiet seclusion so necessary in this type of buildings. La profesión del autor de la iglesia de la Santísima Trinidad queda claramente reflejada en su obra, una de las realizaciones religiosas austríacas más interesantes. Su carácter de escultor no le impone condicionantes técnicos o sociales, por el contrario, le deja libre para buscar el sentido religioso por los medios más distintos. Así, mediante 152 bloques de diferentes tama os y formas configura un diversificado volumen escultórico en el que distribuye ios locales parroquiales y la iglesia propiamente dicha. Estos bloques, alternando con las variadas superficies acristaladas, contribuyen a crear en el interior el ambiente de recogimiento tan necesario en este tipo de construcciones.
Heuristic Derivation of Blackbody Radiation Laws using Principles of Dimensional Analysis
Gerhard Kramm,Fritz Herbert
Physics , 2008,
Abstract: A generalized form of Wien's displacement law and the blackbody radiation laws of (a) Rayleigh and Jeans, (b) Rayleigh, (c) Wien and Paschen, (d) Thiesen and (e) Planck are derived using principles of dimensional analysis. This kind of scaling is expressed in a strictly mathematical manner employing dimensional pi-invariants analysis sometimes called Buckingham's pi-theorem. It is shown that in the case of the classical radiation law of Rayleigh and Jeans only one pi number occurs that has to be considered as a non-dimensional universal constant. This pi number may be determined theoretically or/and empirically. It is also shown that dimensional pi-invariants analysis yields a generalized form of Wien's displacement law. In this instance two pi numbers generally occur. Consequently, a universal function is established that is indispensable to avoid the so-called Rayleigh-Jeans catastrophe in the ultraviolet. Unfortunately, such a universal function cannot be inferred from dimensional arguments. It has to be derived theoretically or/and empirically, too. It is shown that such a similarity function can be deduced on the basis of heuristic principles, when criteria like the maximum condition regarding the generalized form of Wien's displacement law, the requirement of the power law of Stefan and Boltzmann, and Ehrenfest's arguments regarding the red and the violet requirements are adopted.
Osseointegration by bone morphogenetic protein-2 and transforming growth factor beta2 coated titanium implants in femora of New Zealand white rabbits
Thorey Fritz,Menzel Henning,Lorenz Corinna,Gross Gerhard
Indian Journal of Orthopaedics , 2011,
Abstract: Background: Intramembranous bone formation is essential in uncemented joint replacement to provide a mechanical anchorage of the implant. Since the discovery of bone morphogenic proteins (BMPs) by Urist in 1965, many studies have been conducted to show the influence of growth factors on implant ingrowth. In this study, the influence of bone morphogenetic protein-2 (rhBMP-2) and transforming growth factor β2 (TGF-β2) on implant osseointegration was investigated. Materials and Methods: Thirty-two titanium cylinders were implanted into the femoral condyles of both hind legs of New Zealand White Rabbits. Four experimental groups were investigated: controls without coating, a macromolecular copolymer + covalently bound BMP-2, adsorbed BMP-2, and absorbed BMP-2+TGF-β2. All samples were analyzed by ex vivo high-resolution micro-computed-tomography after 28 days of healing. Bone volume per total volume (BV/TV) was recorded around each implant. Afterward, all samples were biomechanically tested in a pull-out setup. Results: The highest BV/TV ratio was seen in the BMP-2 group, followed by the BMP-2+TGF-β2 group in high-resolution micro-computed-tomography. These groups were significantly different compared to the control group (P < 0.05). Copolymer+BMP-2 showed no significant difference in comparison to controls. In the pull-out setup, all groups showed higher fixation strength compared to the control group; these differences were not significant. Conclusions: No differences between BMP-2 alone and a combination of BMP-2+TGF-β2 could be seen in the present study. However, the results of this study confirm the results of other studies that a coating with growth factors is able to enhance bone implant ingrowth. This may be of importance in defect situations during revision surgery to support the implant ingrowth and implant anchorage.
Dust within the old nuclear star cluster in the Milky Way
Sotiris Chatzopoulos,Ortwin Gerhard,Tobias Fritz,Christopher Wegg,Stefan Gillessen
Physics , 2015, DOI: 10.1093/mnras/stv1681
Abstract: The mean absolute extinction towards the central parsec of the Milky Way is A_K~3 mag, including both foreground and Galactic center dust. Here we present a measurement of dust extinction within the Galactic old nuclear star cluster (NSC), based on combining differential extinctions of NSC stars with their u_l proper motions along Galactic longitude. Extinction within the NSC preferentially affects stars at its far side, and because the NSC rotates, this causes higher extinctions for NSC stars with negative u_l, as well as an asymmetry in the u_l-histograms. We model these effects using an axisymmetric dynamical model of the NSC in combination with simple models for the dust distribution. Comparing the predicted asymmetry to data for ~7100 stars in several NSC fields, we find that dust associated with the Galactic center mini-spiral with extinction A_K~=0.15-0.8 mag explains most of the data. The largest extinction A_K~=0.8 mag is found in the region of the Western arm of the mini-spiral. Comparing with total A_K determined from stellar colors, we determine the extinction in front of the NSC. Finally, we estimate that for a typical extinction of A_K~=0.4 the statistical parallax of the NSC changes by ~0.4%.
Rac1-Regulated Endothelial Radiation Response Stimulates Extravasation and Metastasis That Can Be Blocked by HMG-CoA Reductase Inhibitors
Melanie Hamalukic, Johannes Huelsenbeck, Arno Schad, Stefan Wirtz, Bernd Kaina, Gerhard Fritz
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0026413
Abstract: Radiotherapy (RT) plays a key role in cancer treatment. Although the benefit of ionizing radiation (IR) is well established, some findings raise the possibility that irradiation of the primary tumor not only triggers a killing response but also increases the metastatic potential of surviving tumor cells. Here we addressed the question of whether irradiation of normal cells outside of the primary tumor augments metastasis by stimulating the extravasation of circulating tumor cells. We show that IR exposure of human endothelial cells (EC), tumor cells (TC) or both increases TC-EC adhesion in vitro. IR-stimulated TC-EC adhesion was blocked by the HMG-CoA reductase inhibitor lovastatin. Glycyrrhizic acid from liquorice root, which acts as a Sialyl-Lewis X mimetic drug, and the Rac1 inhibitor NSC23766 also reduced TC-EC adhesion. To examine the in vivo relevance of these findings, tumorigenic cells were injected into the tail vein of immunodeficient mice followed by total body irradiation (TBI). The data obtained show that TBI dramatically enhances tumor cell extravasation and lung metastasis. This pro-metastatic radiation effect was blocked by pre-treating mice with lovastatin, glycyrrhizic acid or NSC23766. TBI of mice prior to tumor cell transplantation also stimulated metastasis, which was again blocked by lovastatin. The data point to a pro-metastatic trans-effect of RT, which likely rests on the endothelial radiation response promoting the extravasation of circulating tumor cells. Administration of the widely used lipid-lowering drug lovastatin prior to irradiation counteracts this process, likely by suppressing Rac1-regulated E-selectin expression following irradiation. The data support the concern that radiation exposure might increase the extravasation of circulating tumor cells and recommend co-administration of lipid-lowering drugs to avoid this adverse effect of ionizing radiation.
Malodorous oozing lesions after local cancer treatment - ethacridine powder prevents local infection
Gerhard Dyckhoff,Peter Karl Plinkert,Stefanie Ursula Walk-Fritz,Torsten Hoppe-Tichy
Drugs and Therapy Studies , 2010, DOI: 10.4081/dts.2011.e9
Abstract: A common problem in local cancer treatment is infection of the resulting superficial tumour necrosis. The malodorous oozing lesions not only severely interfere with the patient’s quality of life but may also result in serious sequelae such as accelerated wasting, sepsis, and death. We developed a new formulation of the well-known antiseptic drug Ethacridine lactate in powder form to prevent such infections in local antineoplastic therapy. In a pilot study, the powder was applied in four patients receiving either an intralesional treatment with a platinum-based gel in the course of a study or photodynamic therapy. In all four patients with cervical respectively facial wounds with a surface of up to 80 cm2 a virtually dry and odorless scabby lesion resulted with no signs of infection. These initial clinical experiences suggest that Ethacridine lactate powder may be of benefit in the prevention of infection in palliative intratumoural cancer treatment.
Near action-degenerate periodic-orbit bunches: A skeleton of chaos
Alexander Altland,Petr Braun,Fritz Haake,Stefan Heusler,Gerhard Knieper,Sebastian Müller
Physics , 2009,
Abstract: Long periodic orbits of hyperbolic dynamics do not exist as independent individuals but rather come in closely packed bunches. Under weak resolution a bunch looks like a single orbit in configuration space, but close inspection reveals topological orbit-to-orbit differences. The construction principle of bunches involves close self-"encounters" of an orbit wherein two or more stretches stay close. A certain duality of encounters and the intervening "links" reveals an infinite hierarchical structure of orbit bunches. -- The orbit-to-orbit action differences $\Delta S$ within a bunch can be arbitrarily small. Bunches with $\Delta S$ of the order of Planck's constant have constructively interfering Feynman amplitudes for quantum observables, and this is why the classical bunching phenomenon could yield the semiclassical explanation of universal fluctuations in quantum spectra and transport.
The old nuclear star cluster in the Milky Way: dynamics, mass, statistical parallax, and black hole mass
Sotiris Chatzopoulos,Tobias Fritz,Ortwin Gerhard,Stefan Gillessen,Chris Wegg,Reinhard Genzel,Oliver Pfuhl
Physics , 2014, DOI: 10.1093/mnras/stu2452
Abstract: We derive new constraints on the mass, rotation, orbit structure and statistical parallax of the Galactic old nuclear star cluster (NSC) and the mass of the supermassive black hole. We combine star counts and kinematic data from Fritz et al (2014), including 2'500 line-of-sight velocities and 10'000 proper motions. We show that the difference between the proper motion dispersions sigma_l and sigma_b cannot be explained by rotation, but is a consequence of the flattening of the NSC. We fit the surface density distribution of stars in the central 1000" by a spheroidal cluster with scale ~100" and a much larger nuclear disk component. We compute the two-integral distribution function f(E,Lz) for this density model, and add rotation self-consistently. We find that: (i) The orbit structure of the f(E,Lz) gives an excellent match to the observed velocity dispersion profiles as well as the proper motion and line-of-sight velocity histograms, including the double-peak in the v_l-histograms. (ii) This requires an axial ratio of q= 0.73+-0.04 for r<70" consistent with our determination from star counts. (iii) The NSC is approximately described by an isotropic rotator model. (iv) Using the corresponding Jeans equations to fit the proper motion and line-of-sight velocity dispersions, we obtain best estimates for the NSC mass, black hole mass, and distance M*(r<100")=(8.94+-0.31|stat+-0.9|syst)x10^6Msun, Mbh=(3.86+-0.14|stat+-0.4|syst)x10^6Msun, and R0=8.27+-0.09|stat+-0.1|syst kpc, where the systematic errors estimate additional uncertainties in the dynamical modeling. (v) The combination of the cluster dynamics with the S-star orbits around Sgr A* strongly reduces the degeneracy between black hole mass and Galactic centre distance present in previous S-star studies. A joint statistical analysis with the results of Gillessen et al (2009) gives Mbh=(4.23+-0.14)x10^6Msun and R0=8.33+-0.11kpc.
Engel-like Identities Characterizing Finite Solvable Groups
Tatiana Bandman,Gert-Martin Greuel,Fritz Grunewald,Boris Kunyavskii,Gerhard Pfister,Eugene Plotkin
Mathematics , 2003,
Abstract: In the paper we characterize the class of finite solvable groups by two-variable identities in a way similar to the characterization of finite nilpotent groups by Engel identities. More precisely, a sequence of words $u_1,...,u_n,... $ is called correct if $u_k\equiv 1$ in a group $G$ implies $u_m\equiv 1$ in a group $G$ for all $m>k$. We are looking for an explicit correct sequence of words $u_1(x,y),...,u_n(x,y),...$ such that a group $G$ is solvable if and only if for some $n$ the word $u_n$ is an identity in $G$. Let $u_1=x^{-2}y\min x$, and $u_{n+1} = [xu_nx\min,yu_ny\min]$. The main result states that a finite group $G$ is solvable if and only if for some $n$ the identity $u_n(x,y)\equiv 1$ holds in $G$. In the language of profinite groups this result implies that the provariety of prosolvable groups is determined by a single explicit proidentity in two variables. The proof of the main theorem relies on reduction to J.Thompson's list of minimal non-solvable simple groups, on extensive use of arithmetic geometry (Lang - Weil bounds, Deligne's machinery, estimates of Betti numbers, etc.) and on computer algebra and geometry (SINGULAR, MAGMA) .
Performance of the QuickVue Influenza A+B Rapid Test for Pandemic H1N1 (2009) Virus Infection in Adults
Wolfgang Poeppl, Harald Herkner, Heinz Burgmann, Tom Pustelnik, Gerhard Mooseder, Theresia Popow-Kraupp, Monika Redlberger-Fritz
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0028089
Abstract: To investigate the diagnostic accuracy of the QuickVue? Influenza A+B rapid test we conducted a prospective observational study in which this rapid test was compared with a real-time reverse transcription polymerase chain reaction (RT-PCR) for pandemic influenza A H1N1 (2009) infection in Austrian adults. The sensitivity, specificity, and positive and negative predictive values of the QuickVue test compared with the RT-PCR were 26% (95% CI 18–35), 98% (95% CI 92–100), 94% (95% CI 80–99) and 50% (95% CI 42–58), respectively. The prevalence of pandemic H1N1 (2009) virus infection among the 209 patients included in the study was 57%. Our data suggest that a positive QuickVue test provides considerable information for the diagnosis of pandemic influenza A H1N1 (2009) virus infection in young adults but that a negative QuickVue test result should, if relevant for patient management or public health measures, be verified using PCR.
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