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Search Results: 1 - 10 of 190699 matches for " Silke G?tze "
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Stellate Cells from Rat Pancreas Are Stem Cells and Can Contribute to Liver Regeneration
Claus Kordes, Iris Sawitza, Silke Gtze, Dieter H?ussinger
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0051878
Abstract: The identity of pancreatic stem/progenitor cells is still under discussion. They were suggested to derive from the pancreatic ductal epithelium and/or islets. Here we report that rat pancreatic stellate cells (PSC), which are thought to contribute to pancreatic fibrosis, have stem cell characteristics. PSC reside in islets and between acini and display a gene expression pattern similar to umbilical cord blood stem cells and mesenchymal stem cells. Cytokine treatment of isolated PSC induced the expression of typical hepatocyte markers. The PSC-derived hepatocyte-like cells expressed endodermal proteins such as bile salt export pump along with the mesodermal protein vimentin. The transplantation of culture-activated PSC from enhanced green fluorescent protein-expressing rats into wild type rats after partial hepatectomy in the presence of 2-acetylaminofluorene revealed that PSC were able to reconstitute large areas of the host liver through differentiation into hepatocytes and cholangiocytes. This developmental fate of transplanted PSC was confirmed by fluorescence in situ hybridization of chromosome Y after gender-mismatched transplantation of male PSC into female rats. Transplanted PSC displayed long-lasting survival, whereas muscle fibroblasts were unable to integrate into the host liver. The differentiation potential of PSC was further verified by the transplantation of clonally expanded PSC. PSC clones maintained the expression of stellate cell and stem cell markers and preserved their differentiation potential, which indicated self-renewal potential of PSC. These findings demonstrate that PSC have stem cell characteristics and can contribute to the regeneration of injured organs through differentiation across tissue boundaries.
ECRG4 is a candidate tumor suppressor gene frequently hypermethylated in colorectal carcinoma and glioma
Silke Gtze, Valeska Feldhaus, Thilo Traska, Marietta Wolter, Guido Reifenberger, Andrea Tannapfel, Cornelius Kuhnen, Dirk Martin, Oliver Müller, Sonja Sievers
BMC Cancer , 2009, DOI: 10.1186/1471-2407-9-447
Abstract: In a methylation screening approach, we identified ECRG4 as a differentially methylated gene. We analyzed different cancer cells for ECRG4 promoter methylation by COBRA and bisulfite sequencing. Gene expression analysis was carried out by semi-quantitative RT-PCR. The ECRG4 coding region was cloned and transfected into colorectal carcinoma cells. Cell growth was assessed by MTT and BrdU assays. ECRG4 localization was analyzed by fluorescence microscopy and Western blotting after transfection of an ECRG4-eGFP fusion gene.We found a high frequency of ECRG4 promoter methylation in various cancer cell lines. Remarkably, aberrant methylation of ECRG4 was also found in primary human tumor tissues, including samples from colorectal carcinoma and from malignant gliomas. ECRG4 hypermethylation associated strongly with transcriptional silencing and its expression could be re-activated in vitro by demethylating treatment with 5-aza-2'-deoxycytidine. Overexpression of ECRG4 in colorectal carcinoma cells led to a significant decrease in cell growth. In transfected cells, ECRG4 protein was detectable within the Golgi secretion machinery as well as in the culture medium.ECRG4 is silenced via promoter hypermethylation in different types of human cancer cells. Its gene product may act as inhibitor of cell proliferation in colorectal carcinoma cells and may play a role as extracellular signaling molecule.Genetic and epigenetic events work in concert to transform a normal cell into a malignant cancer cell. Epigenetic alterations in cancer include changes in chromatin structure and in methylation of cytosine residues in the DNA [1]. In comparison with normal cells, the cancer cell genome is hypomethylated which leads to genomic instability through the activation of mobile genetic elements [2]. Concurrently, CpG-rich regions located in many gene promoters may become hypermethylated. The hypermethylation of these 5'-CpG islands may cause transcriptional silencing of genes, including tumo
Der geehrte Autor und die Kunst der Invektive. Zu Thomas Bernhards Meine Preise
Clemens Gtze
Studia Austriaca , 2012, DOI: 10.6092/1593-2508/2184
Abstract: Thomas Bernhard reflects in his posthumously published story collection Meine Preise the most important of his many literary awards, which were often associated with public scandals. This essay examines the mechanisms of authorship and self-stylization in the stories concerning the prizes received, shows the conglomeration of reality and fiction which characterizes his late work and offers a compact, interpretative survey of Bernhard’s prose volume in the light of his career in the literary field.
THE DANISH OMBUDSMAN – A NATIONAL WATCHDOG WITH EUROPEAN RESERVATIONS
Michael GTZE
Transylvanian Review of Administrative Sciences , 2009,
Abstract: The Danish Parliamentary Ombudsman occupies a central position as a watchdog over public authorities within the national context. The statutory and functional powers of the institution are wide and the ombudsman enjoys an a priori sympathy from e.g. Parliament and the media. In addition, there are no specialised administrative courts in Denmark and the ombudsman is thus unrivalled on the legal scene as the primary specialist protector of good administration. Nevertheless, the ombudsman subscribes to a narrow scope of focus in the protection of citizens’ rights. In practice the ombudsman often limits his review to the compliance by authorities of national law and in particular of general procedural requirements. The rights of citizens are only actively protected by the ombudsman as far as certain parts of general administrative law in concerned. The current strategy of selected preferences of the Danish ombudsman leaves European Union rights of citizens largely unidentified and unprotected. The Danish ombudsman is a watchdog with teeth but with discerning taste buds. As to EU Law, the ombudsman is reserved and has no appetite at all.
The Danish ombudsman A national watchdog with selected preferences
Michael Gtze
Utrecht Law Review , 2010,
Abstract: The Danish Parliamentary Ombudsman occupies a central position as a watchdog over public authorities within the national context. The statutory and functional powers of the institution are wide and the ombudsman enjoys a priori sympathy from Parliament and the media. In addition, there are no specialised administrative courts in Denmark and the ombudsman is thus unrivalled on the legal scene as the primary specialist protector of good administration. Nevertheless, the Danish ombudsman subscribes to a narrow scope of focus in the protection of citizens’ rights. In practice, the ombudsman often limits his review to the authorities’ compliance with national law and in particular with general procedural requirements. The rights of citizens are only actively protected by the ombudsman as far as certain parts of general administrative law are concerned. The limited horizon in the control and thinking of the Danish ombudsman leaves the European Union rights of citizens largely unidentified and unprotected. The Danish ombudsman is a watchdog with teeth but with discerning taste buds. As to EU Law, the ombudsman is a watchdog with no appetite at all.
Autonomer, aber weiter unsicher - Neue Führungspositionen haben das Karrieresystem in der deutschen Wissenschaft nur wenig ver ndert
Silke Gülker
Zeitschrift für Nachwuchswissenschaftler , 2010,
Abstract: Der akademische Arbeitsmarkt gilt als starr. Karrieren sind zu wenig planbar. Neue Personalkategorien wie Juniorprofessur oder die Leitung von Nachwuchsgruppen sollten die Wege junger Wissenschaftler bahnen – denn zwischen Abitur und der Erstberufung auf eine unbefristete Professorenstelle liegen durchschnittlich rund 20 Jahre. In der Realit t kommen aber nur wenige Forscher ohne Habilitation ans Ziel.
The Arithmetic of Distributions in Free Probability Theory
G. Chistyakov,F. Gtze
Mathematics , 2005,
Abstract: We give an analytical approach to the definition of additive and multiplicative free convolutions which is based on the theory of Nevanlinna and of Schur functions. We consider the set of probability distributions as a semigroup $\bold M$ equipped with the operation of free convolution and prove a Khintchine type theorem for the factorization of elements of this semigroup. An element of $\bold M$ contains either indecomposable ("prime") factors or it belongs to a class, say $I_0$, of distributions without indecomposable factors. In contrast to the classical convolution semigroup in the free additive and multiplicative convolution semigroups the class $I_0$ consists of units (i.e. Dirac measures) only. Furthermore we show that the set of indecomposable elements is dense in $\bold M$.
Incremental refinement of a multi-user-detection algorithm (II)
M. Vollmer,J. Gtze
Advances in Radio Science : Kleinheubacher Berichte , 2003,
Abstract: Multi-user detection is a technique proposed for mobile radio systems based on the CDMA principle, such as the upcoming UMTS. While offering an elegant solution to problems such as intra-cell interference, it demands very significant computational resources. In this paper, we present a high-level approach for reducing the required resources for performing multi-user detection in a 3GPP TDD multi-user system. This approach is based on a displacement representation of the parameters that describe the transmission system, and a generalized Schur algorithm that works on this representation. The Schur algorithm naturally leads to a highly parallel hardware implementation using CORDIC cells. It is shown that this hardware architecture can also be used to compute the initial displacement representation. It is very beneficial to introduce incremental refinement structures into the solution process, both at the algorithmic level and in the individual cells of the hardware architecture. We detail these approximations and present simulation results that confirm their effectiveness.
A low-power and high-quality implementation of the discrete cosine transformation
B. Heyne,J. Gtze
Advances in Radio Science : Kleinheubacher Berichte , 2007,
Abstract: In this paper a computationally efficient and high-quality preserving DCT architecture is presented. It is obtained by optimizing the Loeffler DCT based on the Cordic algorithm. The computational complexity is reduced from 11 multiply and 29 add operations (Loeffler DCT) to 38 add and 16 shift operations (which is similar to the complexity of the binDCT). The experimental results show that the proposed DCT algorithm not only reduces the computational complexity significantly, but also retains the good transformation quality of the Loeffler DCT. Therefore, the proposed Cordic based Loeffler DCT is especially suited for low-power and high-quality CODECs in battery-based systems.
An Adiabatic Architecture for Linear Signal Processing
M. Vollmer,J. Gtze
Advances in Radio Science : Kleinheubacher Berichte , 2005,
Abstract: Using adiabatic CMOS logic instead of the more traditional static CMOS logic can lower the power consumption of a hardware design. However, the characteristic differences between adiabatic and static logic, such as a four-phase clock, have a far reaching influence on the design itself. These influences are investigated in this paper by adapting a systolic array of CORDIC devices to be implemented adiabatically. We present a means to describe adiabatic logic in VHDL and use it to define the systolic array with precise timing and bit-true calculations. The large pipeline bubbles that occur in a naive version of this array are identified and removed to a large degree. As an example, we demonstrate a parameterization of the CORDIC array that carries out adaptive RLS filtering.
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