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Search Results: 1 - 10 of 40 matches for " KOVAR "
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Dr. Jekyll and Mr. Hyde: The Two Faces of the FUS/EWS/TAF15 Protein Family
Heinrich Kovar
Sarcoma , 2011, DOI: 10.1155/2011/837474
Abstract: FUS, EWS, and TAF15 form the FET family of RNA-binding proteins whose genes are found rearranged with various transcription factor genes predominantly in sarcomas and in rare hematopoietic and epithelial cancers. The resulting fusion gene products have attracted considerable interest as diagnostic and promising therapeutic targets. So far, oncogenic FET fusion proteins have been regarded as strong transcription factors that aberrantly activate or repress target genes of their DNA-binding fusion partners. However, the role of the transactivating domain in the context of the normal FET proteins is poorly defined, and, therefore, our knowledge on how FET aberrations impact on tumor biology is incomplete. Since we believe that a full understanding of aberrant FET protein function can only arise from looking at both sides of the coin, the good and the evil, this paper summarizes evidence for the central function of FET proteins in bridging RNA transcription, processing, transport, and DNA repair.
Downstream EWS/FLI1 - upstream Ewing's sarcoma
Heinrich Kovar
Genome Medicine , 2010, DOI: 10.1186/gm129
Abstract: Ewing's sarcoma family tumors (ESFTs) are a group of mostly undifferentiated, highly aggressive, small round-cell tumors affecting mostly children and adolescents, with a peak incidence around 15 years of age [1]. Their origin has been a matter of debate ever since they were first described in 1921 by James Ewing [2]. Although presenting predominantly as a neoplasm of the bone, the exact tumor histogenesis remains poorly defined, and rare occurrences in the soft tissue of other organs [3] point to a pluripotent migratory cell of origin.The unifying genetic trait of this family of tumors is a chromosomal translocation, t(11;22)(q24;q12), that was first described more than 20 years ago [4] and molecularly elucidated in 1992 [5]. The genomic rearrangement results in the fusion of two genes, EWS and FLI1. EWS encodes a RNA-binding protein that associates with components of the basal transcriptional machinery [6-8] and post-transcriptional RNA processing [9-12], and EWS knockout mice are deficient in homologous recombination and recombination repair [13]. FLI1 encodes a member of the ETS protein family, a group of winged helix-loop-helix transcription factors sharing a DNA-binding domain with specificity for GGAA/T core motifs. In the ESFT-specific EWS/FLI1 fusion protein, the EWS RNA-binding domain is replaced by the FLI1 DNA-binding domain, thus creating a novel ETS transcription factor with unique properties. In about 10-15% of ESFTs, one of four related ETS transcription factors (ERG, ETV1, ETV4 or FEV) substitutes for FLI1 in alternative but identically structured EWS fusion proteins [14].Functional studies of ectopically expressed EWS/FLI1 using promiscuous ETS binding sites to drive reporter gene activity revealed that the amino-terminal EWS domain contributes strong transcriptional activation properties to EWS/ETS fusion proteins [15-17]. Early expression profiling studies of EWS/FLI1-transduced cell line models confirmed that a plethora of genes are upregulated
The Supply Side of Second-Order Elections in the Czech Republic: A Light at the End of the Tunnel?
Jan Kovar
Romanian Journal of European Affairs (RJEA) , 2013,
Abstract: This paper attempts to contribute to the debate on the Europeanization of European Parliament elections. Because these elections are supposedly fought over national political issues, the analysis focuses on one aspect of political parties' supply for these elections, namely their election programmes. To this aim, a content analysis is conducted, within a comparative framework, of selected Czech political parties' programmatic documents. At the same time, the question is asked: to what extent do these programmes offer EU-level solutions-in other words, in terms of issues, does Europeanization or domestication prevail in the manifestos? The results show that parties focus on EU issues in their Euro manifestos and feature an apparent degree of Europeanization of this part of their supply for EP elections. From this perspective, these results can be considered a light at the end of the (second-order) tunnel, given that at least the programmatic part of parties' supply is about European integration after all.
Generation of the Narrow Band Digital Modulated Signals Using Quadrature Digital Upconverter
P. Kovar
Radioengineering , 2003,
Abstract: The paper deals with the modern approach to generation of digitalmodulated signals at intermediate frequency in digital way. The commondigital modulator is based on analogue Quadrature modulator. The modernVLSI integrated circuits enable to implement this signal processingmethod in digital form. Analog and digital approaches are compared inthis document. The measurement of narrow band D8PSK modulation signalgenerated by Quadrature Digital Upconverter is presented in this paper.
Progress in the Molecular Biology of Ewing Tumors
Heinrich Kovar
Sarcoma , 1998, DOI: 10.1080/13577149878109
Abstract:
Dr. Jekyll and Mr. Hyde: The Two Faces of the FUS/EWS/TAF15 Protein Family
Heinrich Kovar
Sarcoma , 2011, DOI: 10.1155/2011/837474
Abstract: FUS, EWS, and TAF15 form the FET family of RNA-binding proteins whose genes are found rearranged with various transcription factor genes predominantly in sarcomas and in rare hematopoietic and epithelial cancers. The resulting fusion gene products have attracted considerable interest as diagnostic and promising therapeutic targets. So far, oncogenic FET fusion proteins have been regarded as strong transcription factors that aberrantly activate or repress target genes of their DNA-binding fusion partners. However, the role of the transactivating domain in the context of the normal FET proteins is poorly defined, and, therefore, our knowledge on how FET aberrations impact on tumor biology is incomplete. Since we believe that a full understanding of aberrant FET protein function can only arise from looking at both sides of the coin, the good and the evil, this paper summarizes evidence for the central function of FET proteins in bridging RNA transcription, processing, transport, and DNA repair. 1. Introduction The Strange Case of Dr. Jekyll and Mr. Hyde, a novel by the Scottish poet Robert Luis Stevenson (1850–1894), screened multiple times worldwide, describes the struggle between the good and evil sides of one individual [1]. At daylight, Dr. Jekyll is an honorable member of the society, but when the light fades he turns into an evil beast. The coexistence of two faces of one individual has inspired more than poetry and psychology. The question of which circumstances favor the surfacing of one or the other and how it may be influenced is relevant to all areas of life, including economy, technology and medicine. Cancer unravels the “Hyde” side of genes and their biology, but we can learn about how to tame fierce Mr. Hyde by understanding the Dr. Jekyll behind, the normal function of cancer genes. FET (FUS, EWS, TAF15) proteins are a ubiquitously expressed family of similarly structured proteins predominantly localizing to the nuclear [2]. FET genes have attracted broad attention since all known members are found involved in deleterious genomic rearrangements with transcription factor genes in a variety of human sarcomas and acute leukemias. Chimeric FET proteins are considered and mostly studied as aberrant transcription factors. This paper aims at summarizing the good sides of FET proteins and looking at the characteristics of aberrant FET proteins as Dr. Jekyll’s second face which surfaces only upon gene rearrangement or mutation. 2. Dr. Jekyll 2.1. The FET Family of Proteins The prototype FET protein EWS was identified in 1992 as the gene product
Ranging Property of the Dual-Band Band Limited Signal (DBBLS)
KOVAR, P.,KACMARIK, P.
Advances in Electrical and Computer Engineering , 2012, DOI: 10.4316/aece.2012.03014
Abstract: The Dual-Band Band Limited Signal (DBBLS) is a signal with its power spectral density consisting of two separate lobes. Signals that can be considered as DBBLS are for example signals with BOC, AltBOC modulation, signals modulated on two close carriers and many other signals, which are used in modern satellite navigation systems. This signal advantage is its excellent ranging property. The parted power spectral density enables processing the DBBLS as a single wideband signal in single-channel receiver or as two narrow band signals in two-channel receiver. The signal processing of the ranging signals is based on the calculation of the cross-correlation function, which can be calculated from the signal measured by the two-channel receiver by the derived method more efficiently than from the whole signal. The two-channel processing has nearly optimal performance, but the hardware and computation complexity is much lower. The developed method can by applied, for instance, for the processing of the Galileo E5 signal or pair of the Compass L1 signals.
Forces in Kerr spacetimes with a repulsive cosmological constant
Jiri Kovar,Zdenek Stuchlik
Physics , 2006, DOI: 10.1142/S0217751X06032435
Abstract: Forces defined in the framework of optical reference geometry are introduced in the case of stationary and axially symmetric Kerr black-hole and naked-singularity spacetimes with a repulsive cosmological constant. Properties of the forces acting on test particles moving along circular orbits in the equatorial plane are discussed, whereas it is shown where the gravitational force vanishes and changes its orientation and where the centrifugal force vanishes and changes its orientation independently of the velocity of test particles related to the optical geometry; the Coriolis force does not vanish for the velocity being non-zero. The spacetimes are classified according to the number of circular orbits where the gravitational and centrifugal forces vanish.
Optical reference geometry and inertial forces in Kerr-de Sitter spacetimes
Jiri Kovar,Zdenek Stuchlik
Physics , 2007, DOI: 10.1088/0264-9381/24/3/004
Abstract: Optical reference geometry and related concept of inertial forces are investigated in Kerr-de Sitter spacetimes. Properties of the inertial forces are summarized and their typical behaviour is illustrated. The intuitive 'Newtonian' application of the forces in the relativistic dynamics is demonstrated in the case of the test particle circular motion, static equilibrium positions and perfect fluid toroidal configurations. Features of the optical geometry are illustrated by the embedding diagrams of its equatorial plane. The embedding diagrams do not cover whole the stationary regions of the spacetimes, therefore the limits of embeddability are established. A shape of the embedding diagrams is related to the behaviour of the centrifugal force and it is characterized by the number of turning points of the diagrams. Discussion of the number of embeddable photon circular orbits is also included and the typical embedding diagrams are constructed. The Kerr-de Sitter spacetimes are classified according to the properties of the inertial forces and embedding diagrams.
Equilibrium conditions of spinning test particles in Kerr-de Sitter spacetimes
Zdenek Stuchlik,Jiri Kovar
Physics , 2006, DOI: 10.1088/0264-9381/23/11/016
Abstract: Equilibrium conditions and spin dynamics of spinning test particles are discussed in the stationary and axially symmetric Kerr-de Sitter black-hole or naked-singularity spacetimes. The general equilibrium conditions are established, but due to their great complexity, the detailed discussion of the equilibrium conditions and spin dynamics is presented only in the simple and most relevant cases of equilibrium positions in the equatorial plane and on the symmetry axis of the spacetimes. It is shown that due to the combined effect of the rotation of the source and the cosmic repulsion the equilibrium is spin dependent in contrast to the spherically symmetric spacetimes. In the equatorial plane, it is possible at the so-called static radius, where the gravitational attraction is balanced by the cosmic repulsion, for the spinless particles as well as for spinning particles with arbitrarily large azimuthal-oriented spin or at any radius outside the ergosphere with a specifically given spin orthogonal to the equatorial plane. On the symmetry axis, the equilibrium is possible at any radius in the stationary region and is given by an appropriately tuned spin directed along the axis. At the static radii on the axis the spin of particles in equilibrium must vanish.
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