| 1. |
- Paturzo, M., et al.
(author)
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On the origin of internal field in lithium niobate crystals directly observed by digital holography
- 2005
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In: Optics express. - 1094-4087. ; 13:14, s. 5416-
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Journal article (peer-reviewed)abstract
- We show the defect dependence of the internal field in Lithium Niobate using a full-field interferometric method and demonstrate that it can be directly measured on some clusters of defects embedded in a stoichiometric matrix. Results show that the value of the internal field grows in proximity of defects and vanishes far from them, which addresses the long-standing issue about its origin in Lithium Niobate crystal.
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| 2. |
- Fuxe, K., et al.
(author)
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Receptor-receptor interactions within receptor mosaics : Impact on neuropsychopharmacology
- 2008
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In: Brain Research Reviews. - : Elsevier BV. - 0165-0173 .- 1872-6321. ; 58:2, s. 415-452
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Research review (peer-reviewed)abstract
- Future therapies for diseases associated with altered dopaminergic signaling, including Parkinson's disease, schizophrenia and drug addiction or drug dependence may substantially build on the existence of intramembrane receptor-receptor interactions within dopamine receptor containing receptor mosaics (RM; dimeric or high-order receptor oligomers) where it is believed that the dopamine D-2 receptor may operate as the 'hub receptor' within these complexes. The constitutive adenosine A(2A)/dopamine D-2 RM, located in the dorsal striatopallidal GABA neurons, are of particular interest in view of the demonstrated antagonistic A(2A)/D-2 interaction within these heteromers; an interaction that led to the suggestion and later demonstration that A(2A) antagonists could be used as novel anti-Parkinsonian drugs. Based on the likely existence of A(2A)/D-2/mGluR5 RM located both extrasynaptically on striato-pallidal GABA neurons and on cortico-striatal glutamate terminals, multiple receptor-receptor interactions within this RM involving synergism between A(2A)/mGluR5 to counteract D-2 signaling, has led to the proposal of using combined mGluR5 and A(2A) antagonists as a future anti-Parkinsonian treatment. Based on the same RM in the ventral striato-pallidal GABA pathways, novel strategies for the treatment of schizophrenia, building on the idea that A(2A) agonists and/or mGluR5 agonists will help reduce the increased dopaminergic signaling associated with this disease, have been suggested. Such treatment may ensure the proper glutamatergic drive from the mediodorsal thalamic nucleus to the prefrontal cortex, one which is believed to be reduced in schizophrenia due to a dominance of D-2-like signaling in the ventral striatum. Recently, A(2A) receptors also have been shown to counteract the locomotor and sensitizing actions of cocaine and increases in A(2A) receptors have also been observed in the nucleus accumbens after extended cocaine self-administration, probably representing a compensatory up-regulation to counteract the cocaine-induced increases in dopamine D-2 and D-3 signaling. Therefore, A(2A) agonists, through antagonizing D-2 and D-3 signaling within A(2A)/D-2 and A(2)/D-3 RM heteromers in the nucleus accumbens, may be found useful as a treatment for cocaine dependence. Furthermore, antagonistic cannabinoid CB1/D-2 interactions requiring A(2A) receptors have also been discovered and possibly operate in CB1/D-2/A(2A) RM located principally on striatal glutamate terminals but also on some ventral striato-pallidal GABA neurons, thereby opening up a new mechanism for the integration of endocannabinoid, DA and adenosine mediated signals. Thus, A(2A), mGluR5 and/or CB1 receptors can form integrative units with D-2 receptors within RM displaying different compositions, topography and localization. Also galaninR/5-HT1A RM probably participates in the transmission of the ascending 5-hydroxytryptamine neurons, where galanin receptors antagonize 5-HT1A recognition and signaling. Subtype specific galanin receptor antagonists may therefore represent novel antidepressant drugs. These results suggest the importance of a complete understanding of the function of these RM with regard to disease. Ultimately receptor-recepor interactions within RM that modify dopaminergic and serotonergic signaling may give new strategies for treatment of a wide range of diseases associated with altered dopaminergic and serotonergic signaling.
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| 3. |
- Hossain, M. Akhter, et al.
(author)
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The A-chain of the human relaxin family peptides has distinct roles in the binding and activation of the different relaxin family peptide receptors
- 2008
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In: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 283:25, s. 17287-17297
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Journal article (peer-reviewed)abstract
- The relaxin peptides are a family of hormones that share a structural fold characterized by two chains, A and B, that are cross-braced by three disulfide bonds. Relaxins signal through two different classes of G-protein-coupled receptors (GPCRs), leucine-rich repeat-containing GPCRs LGR7 and LGR8 together with GPCR135 and GPCR142, now referred to as the relaxin family peptide (RXFP) receptors 1-4, respectively. Although key binding residues have been identified in the B-chain of the relaxin peptides, the role of the A-chain in their activity is currently unknown. A recent study showed that INSL3 can be truncated at the N terminus of its A-chain by up to 9 residues without affecting the binding affinity to its receptor RXFP2 while becoming a high affinity antagonist. This suggests that the N terminus of the INSL3 A-chain contains residues essential for RXFP2 activation. In this study, we have synthesized A-chain truncated human relaxin-2 and -3 (H2 and H3) relaxin peptides, characterized their structure by both CD and NMR spectroscopy, and tested their binding and cAMP activities on RXFP1, RXFP2, and RXFP3. In stark contrast to INSL3, A-chain-truncated H2 relaxin peptides lost RXFP1 and RXFP2 binding affinity and concurrently cAMP-stimulatory activity. H3 relaxin A-chain-truncated peptides displayed similar properties on RXFP1, highlighting a similar binding mechanism for H2 and H3 relaxin. In contrast, A-chain-truncated H3 relaxin peptides showed identical activity on RXFP3, highlighting that the B-chain is the sole determinant of the H3 relaxin-RXFP3 interaction. Our results provide new insights into the action of relaxins and demonstrate that the role of the A-chain for relaxin activity is both peptide- and receptor-dependent.
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| 4. |
- Marzolla, M., et al.
(author)
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Open standards-based interoperability of job submission and management interfaces across the grid middleware platforms gLite and UNICORE
- 2007
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In: Proceedings - e-Science 2007, 3rd IEEE International Conference on e-Science and Grid Computing. - : IEEE Computer Society. - 0769530648 - 9780769530642 ; , s. 592-599
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Conference paper (peer-reviewed)abstract
- In a distributed Grid environment with ambitious service demands the job submission and management interfaces provide functionality of major importance. Emerging e-Science and Grid infrastructures such as EGEE and DEISA rely on highly available services that are capable of managing scientific jobs. It is the adoption of emerging open standard interfaces which allows the distribution of Grid resources in such a way that their actual service implementation or Grid technologies are not isolated from each other, especially when these resources are deployed in different e-Science infrastructures that consist of different types of computational resources. This paper motivates the interoperability of these infrastructures and discusses solutions. We describe the adoption of various open standards that recently emerged from the Open Grid Forum (OGF) in the field of job submission and management by well-known Grid technologies, respectively gLite and UNICORE. This has a fundamental impact on the interoperability between these technologies and thus within the next generation e-Science infrastructures that rely on these technologies.
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| 5. |
- Riedel, M., et al.
(author)
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Improving e-Science with Interoperability of the e-Infrastructures EGEE and DEISA
- 2008
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In: MIPRO 2008 - 31st International Convention Proceedings. - 9789532330366 ; , s. 225-231
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Conference paper (peer-reviewed)abstract
- In the last couple of years, many e-Science infrastructures have begun to offer production services to e- Scientists with an increasing number of applications that require access to different kinds of computational resources. Within Europe two rather different multi-national e-Science infrastructures evolved over time namely Distributed European Infrastructure for Supercomputing Applications (DEISA) and Enabling Grids for E-SciencE (EGEE). DEISA provides access to massively parallel systems such as supercomputers that are well suited for scientific applications that require many interactions between their typically high numbers of CPUs. EGEE on the other hand provides access to a world-wide Grid of university clusters and PC pools that are well suited for farming applications that require less or even no interactions between the distributed CPUs. While DEISA uses the HPC-driven Grid technology UNICORE, EGEE is based on the gLite Grid middleware optimized for farming jobs. Both have less adoption of open standards and therefore both systems are technically non-interoperable, which means that no e-Scientist can easily leverage the DEISA and EGEE infrastructure with one suitable client environment for scientific applications. This paper argues that future interoperability of such large e-Science infrastructures is required to improve e-Science in general and to increase the real scientific impact of world-wide Grids in particular. We discuss the interoperability achieved by the OMII-Europe project that fundamentally improved the interoperability between UNICORE and gLite by using open standards. We also outline one specific scientific scenario of the WISDOM initiative that actually benefits from the recently established interoperability.
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| 6. |
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