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Search Results: 1 - 10 of 219511 matches for " C. Hagner "
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Cómo funciona la mente: La representación visual de los procesos cerebrales
Hagner, Michael
Arbor : Ciencia, Pensamiento y Cultura , 2010, DOI: 10.3989/arbor.2010.743n1208
Abstract: This paper offers an account on the history of visualization, in particular the visualization of brain activity, through a description of different sets of theories and techniques, dating back to the nineteenth century up to the present day, designed to represent mental processes. Este trabajo ofrece un repaso de la historia de la visualización de los procesos mentales a través de la descripción de las diferentes tecnologías desarrolladas desde el siglo XIX hasta nuestros días destinadas a representar la actividad cerebral.
Cancer chemotherapy: targeting folic acid synthesis
Nicole Hagner, Markus Joerger
Cancer Management and Research , 2010, DOI: http://dx.doi.org/10.2147/CMAR.S10043
Abstract: ncer chemotherapy: targeting folic acid synthesis Review (6055) Total Article Views Authors: Nicole Hagner, Markus Joerger Published Date November 2010 Volume 2010:2 Pages 293 - 301 DOI: http://dx.doi.org/10.2147/CMAR.S10043 Nicole Hagner, Markus Joerger Department of Medical Oncology, Cantonal Hospital, St Gallen, Switzerland Abstract: Antifolates are structural analogs of folates, essential one-carbon donors in the synthesis of DNA in mammalian cells. Antifolates are inhibitors of key enzymes in folate metabolism, namely dihydrofolate reductase, β-glycinamide ribonucleotide transformylase, 5'-amino-4'-imidazolecarboxamide ribonucleotide transformylase, and thymidylate synthetase. Methotrexate is one of the earliest anticancer drugs and is extensively used in lymphoma, acute lymphoblastic leukemia, and osteosarcoma, among others. Pemetrexed has been approved in combination with cisplatin as first-line treatment for advanced non-squamous-cell lung cancer, as a single agent for relapsed non-small-cell lung cancer after platinum-containing chemotherapy, and in combination with cisplatin for the treatment of pleural mesothelioma. Raltitrexed is approved in many countries (except in the United States) for advanced colorectal cancer, but its utilization is mainly limited to patients intolerant to 5-fluorouracil. Pralatrexate has recently been approved in the United States for relapsed or refractory peripheral T-cell lymphoma. This article gives an overview of the cellular mechanism, pharmacology, and clinical use of classical and newer antifolates and discusses some of the main resistance mechanisms to antifolate drugs.
Cancer chemotherapy: targeting folic acid synthesis
Nicole Hagner,Markus Joerger
Cancer Management and Research , 2010,
Abstract: Nicole Hagner, Markus JoergerDepartment of Medical Oncology, Cantonal Hospital, St Gallen, SwitzerlandAbstract: Antifolates are structural analogs of folates, essential one-carbon donors in the synthesis of DNA in mammalian cells. Antifolates are inhibitors of key enzymes in folate metabolism, namely dihydrofolate reductase, β-glycinamide ribonucleotide transformylase, 5'-amino-4'-imidazolecarboxamide ribonucleotide transformylase, and thymidylate synthetase. Methotrexate is one of the earliest anticancer drugs and is extensively used in lymphoma, acute lymphoblastic leukemia, and osteosarcoma, among others. Pemetrexed has been approved in combination with cisplatin as first-line treatment for advanced non-squamous-cell lung cancer, as a single agent for relapsed non-small-cell lung cancer after platinum-containing chemotherapy, and in combination with cisplatin for the treatment of pleural mesothelioma. Raltitrexed is approved in many countries (except in the United States) for advanced colorectal cancer, but its utilization is mainly limited to patients intolerant to 5-fluorouracil. Pralatrexate has recently been approved in the United States for relapsed or refractory peripheral T-cell lymphoma. This article gives an overview of the cellular mechanism, pharmacology, and clinical use of classical and newer antifolates and discusses some of the main resistance mechanisms to antifolate drugs.Keywords: antifolates, cancer, molecular pharmacology, pemetrexed, methotrexate, folate metabolism
Long-Term Stability of Underground Operated CZT Detectors Based on the Analysis of Intrinsic $^{113}$Cd β$^{-}$-Decay
J. Ebert,C. Goessling,D. Gehre,C. Hagner,N. Heidrich,R. Klingenberg,K. Kroeninger,C. Nitsch,C. Oldorf,T. Quante,S. Rajek,H. Rebber,K. Rohatsch,J. Tebruegge,R. Temminghoff,R. Theinert,J. Timm,B. Wonsak,S. Zatschler,K. Zuber
Physics , 2015,
Abstract: The COBRA collaboration operates a demonstrator setup at the underground facility LNGS (Laboratori Nazionali del Gran Sasso, located in Italy) to prove the technological capabilities of this concept for the search for neutrinoless double beta-decay. The setup consists of 64 $(1\times\!1\times\!1)$ cm$^{3}$ CZT detectors in CPG configuration. One purpose of this demonstrator is to test if reliable long-term operation of CZT-CPG detectors in such a setup is possible. The demonstrator has been operated under ultra low-background conditions since more than three years and collected data corresponding to an exposure of 218 kg$\cdot$days. The presented study focuses on the long-term stability of CZT detectors by analyzing the intrinsic, fourfold forbidden non-unique $^{113}$Cd single beta-decay. It can be shown that CZT detectors can be operated stably for long periods of time and that the $^{113}$Cd single beta-decay can be used as an internal monitor of the detector performance during the runtime of the experiment.
Runtime Analysis and Adaptation of a Hard Real-Time Robotic Control System
Jens Steiner,Matthias Hagner,Ursula Goltz
Journal of Computers , 2007, DOI: 10.4304/jcp.2.10.18-27
Abstract: The increasing complexity of technical systems often leads to problems when they are to be maintained, changed or extended. Nature inspired concepts like selfmanagement or self-organization have found their way into technical systems to overcome the complexity problems. In turn those systems exhibit beneficial self-* properties like self-optimization, self-healing or self-protection. This paper presents a software architecture for the control of parallel kinematic machines and its evolvement to a selfadaptive system that strives to optimize, protect and heal itself. A software engineering approach for the development of self-managing components is introduced that is supported by behavior validation in a specialized simulation environment. The first realization of a self-manager, responsible for the distribution of control components, is described in detail to show that self-management is feasible in robotic control. The self-manager uses formal analysis techniques during the runtime of the system to make sure it always conforms to its real-time requirements.
Current Status and Future Perspectives of the COBRA Experiment
J. Ebert,M. Fritts,C. G??ling,T. G?pfert,D. Gehre,C. Hagner,N. Heidrich,T. K?ttig,T. Neddermann,C. Oldorf,T. Quante,S. Rajek,O. Reinecke,O. Schulz,J. Tebrügge,J. Timm,B. Wonsak,K. Zuber
Advances in High Energy Physics , 2013, DOI: 10.1155/2013/703572
Abstract: The aim of the COBRA experiment is to prove the existence of neutrinoless double-beta-decay ( -decay) and to measure its half-life. For this purpose a detector array made of cadmium-zinc-telluride (CdZnTe) semiconductor detectors is operated at the Gran Sasso Underground Laboratory (LNGS) in Italy. This setup is used to investigate the experimental issues of operating CdZnTe detectors in low-background mode and to identify potential background components, whilst additional studies are proceeding in surface laboratories. The experiment currently consists of monolithic, calorimetric detectors of coplanar grid design (CPG detectors). These detectors are 1 × 1 × 1?cm3 and are arranged in 4 × 4 detector layers. Ultimately four layers will be installed by the end of 2013, of which two are currently operating. To date 82.3?kg·days of data have been collected. In the region of interest for 116Cd around 2.8?MeV, the median energy resolution is 1.5% FWHM, and a background level near 1 counts/keV/kg/y has been reached. This paper gives an overview of the current status of the experiment and future perspectives. 1. Introduction Among the outstanding issues of modern particle physics are measuring the absolute mass scale of the neutrino and the determination of whether neutrinos are Majorana or Dirac particles. This motivates searching for 0 -decay, because its existence would be an unambiguous sign for the Majorana character of the neutrino and would be a probe of the absolute mass. Additionally, as a lepton number violating process, 0 -decay is a probe of physics beyond the standard model [1]. Searches for 0 -decay require a source of double-beta-decay isotopes and a low-background detection system. The Cadmium Zinc Telluride 0-Neutrino Double-Beta Research Apparatus (COBRA) experiment, proposed in [2], uses CdZnTe crystals as both source and detector material. Within this material, nine isotopes are double-beta-decay candidates (see Table 1), the most promising being Te and Cd. The main virtue of Te is its very high natural abundance of 33.8%, whereas Cd is superior due to its higher -value of 2814?keV, which lies above the Tl peak at 2615?keV, the highest energy gamma line of significant intensity from natural radioactivity. This advantage is quite crucial: not only does a higher -value increase the phase space—and thus the probability—for the sought-after decay, but it also reduces the gamma background from natural radioactivity by more than one order of magnitude with respect to isotopes with -values below the Tl peak. In contrast to other semiconductor or
Interplay of spin and orbital magnetogyrotropic photogalvanic effects in InSb/AlInSb quantum well structures
S. Stachel,P. Olbrich,C. Zoth,U. Hagner,T. Stangl,C. Karl,P. Lutz,V. V. Bel'kov,S. K. Clowes,T. Ashley,A. M. Gilbertson,S. D. Ganichev
Physics , 2011, DOI: 10.1103/PhysRevB.85.045305
Abstract: We report on the observation of linear and circular magnetogyrotropic photogalvanic effects in InSb/AlInSb quantum well structures. We show that intraband (Drude-like) absorption of terahertz radiation in the heterostructures causes a dc electric current in the presence of an in-plane magnetic field. The photocurrent behavior upon variation of the magnetic field strength, temperature and wavelength is studied. We show that at moderate magnetic fields the photocurrent exhibits a typical linear field dependence. At high magnetic fields, however, it becomes nonlinear and inverses its sign. The experimental results are analyzed in terms of the microscopic models based on asymmetric relaxation of carriers in the momentum space. We demonstrate that the observed nonlinearity of the photocurrent is caused by the large Zeeman spin splitting in InSb/AlInSb structures and an interplay of the spin-related and spin-independent roots of the magnetogyrotropic photogalvanic effect.
The COBRA demonstrator at the LNGS underground laboratory
The COBRA collaboration,J. Ebert,M. Fritts,D. Gehre,C. G??ling,T. G?pfert,C. Hagner,N. Heidrich,R. Klingenberg,T. K?ttig,K. Kr?ninger,T. Michel,T. Neddermann,C. Nitsch,C. Oldorf,T. Quante,S. Rajek,H. Rebber,O. Reinecke,K. Rohatsch,O. Schulz,A. S?rensen,I. Stekl,J. Tebrügge,R. Temminghoff,R. Theinert,J. Timm,T. Wester,B. Wonsak,S. Zatschler,K. Zuber
Physics , 2015, DOI: 10.1016/j.nima.2015.10.079
Abstract: The COBRA demonstrator, a prototype for a large-scale experiment searching for neutrinoless double beta-decay, was built at the underground laboratory Laboratori Nazionali del Gran Sasso (LNGS) in Italy. It consists of an array of 64 monolithic, calorimetric CdZnTe semiconductor detectors with a coplanar-grid design and a total mass of 380g. It is used to investigate the experimental challenges faced when operating CdZnTe detectors in low-background mode, to identify potential background sources and to show the long-term stability of the detectors. The first data-taking period started in 2011 with a subset of the detectors, while the demonstrator was completed in November 2013. To date, more than 250kg d of data have been collected. This paper describes technical details of the experimental setup and the hardware components.
The Drift Chambers Of The Nomad Experiment
M. Anfreville,P. Astier,M. Authier,A. Baldisseri,M. Banner,N. Besson,J. Bouchez,A. Castera,O. Cloue,J. Dumarchez,L. Dumps,E. Gangler,J. Gosset,C. Hagner,C. Jollec,C. Lachaud,A. Letessier,J. M. Levy,L. Linssen,J. P. Meyer,J. P. Ouriet,J. P. Passerieux,T. Pedrol,A. Placci,J. Poinsignon,B. Popov,P. Rathouit,K. Schahmaneche,T. Stolarczyk,V. Uros,F. Vannucci,M. Vo,H. Zaccone
Physics , 2001, DOI: 10.1016/S0168-9002(01)01371-7
Abstract: We present a detailed description of the drift chambers used as an active target and a tracking device in the NOMAD experiment at CERN. The main characteristics of these chambers are a large area, a self supporting structure made of light composite materials and a low cost. A spatial resolution of 150 microns has been achieved with a single hit efficiency of 97%.
Evaluation of the Reconfiguration of the Data Acquisition System for 3D USCT
Matthias Birk,Clemens Hagner,Matthias Balzer,Nicole V. Ruiter,Michael Hübner,Jürgen Becker
International Journal of Reconfigurable Computing , 2011, DOI: 10.1155/2011/952937
Abstract: As today's standard screening methods often fail to diagnose breast cancer before metastases have developed, an earlier breast cancer diagnosis is still a major challenge. To improve this situation, we are currently developing a fully three-dimensional ultrasound computer tomography (3D USCT) system, promising high-quality volume images of the breast. For obtaining these images, a time-consuming reconstruction has to be performed. As this is currently done on a PC, parallel processing in reconfigurable hardware could accelerate both signal and image processing. In this work, we investigated the suitability of an existing data acquisition (DAQ) system for further computation tasks. The reconfiguration features of the embedded FPGAs have been exploited to enhance the systems functionality. We have adapted the DAQ system to allow for bidirectional communication and to provide an overall process control. Our results show that the studied system can be applied for data processing. 1. Introduction Breast cancer is the most common type of cancer among women in Europe and North America. Unfortunately, in today’s standard screening methods, breast cancer is often initially diagnosed after metastases have already developed [1]. The presence of metastases decreases the survival probability of the patient significantly. Thus, early breast cancer diagnosis is still a major challenge. A more sensitive imaging method could allow for detection in an earlier state and thus enhance the survival probability. With this ultimate goal, we are researching and developing a three-dimensional ultrasound computer tomography (3D USCT) system for early breast cancer diagnosis [2]. This method promises reproducible volume images of the female breast fully in 3D. Our initial measurements of clinical breast phantoms using the first 3D prototype showed promising results [3, 4] and led to a new and optimized aperture setup [5], currently built and shown in Figure 1. It is equipped with over 2000 ultrasound transducers. Further virtual positions of the ultrasound transducers are created by rotational and translational movements of the complete sensor aperture. Figure 1: Image of the semiellipsoidal aperture of the new 3D USCT II. It is equipped with 628 ultrasound senders and 1413 receivers, grouped into 157 transducer array systems, mounted at the inner surface of the measurement basin. In USCT, the interaction of unfocused ultrasonic waves with an imaged object is recorded from many different angles. During a measurement, the emitters sequentially send an ultrasonic wave front which
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