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  • 1
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 68 (1997), S. 0 
    ISSN: 1471-4159
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Abstract: Basic fibroblast growth factor (FGF-2) is abundant in the developing and adult brain and has been linked with the origin and growth of neuronal and glial cells. Glial cells produce high levels of FGF-2, stimulating autocrine growth as well as the survival and function of neurons in a paracrine manner. Abnormal levels of FGF-2 have been linked with Alzheimer's, Huntington's, and Parkinson's diseases. Recent evidence has suggested that a component of the mitogenic response of glial cells is exerted on FGF-2 at the transcriptional level. To assess transcriptional regulation of this potent growth factor, we cloned a 1.4-kb genomic fragment containing the rat FGF-2 promoter region. DNA blotting results indicated that the rat FGF-2 gene exists as a single copy in the genome. The promoter region contains no TATA box but appears to rely instead on multiple GC-rich start sites (P0, P1, and P2) for transcription initiation in rat brain as well as C6 glioma cells. One of these sites (P0) was located within four nucleotides of the reported 5′ end of the rat brain cDNA and constituted part of a consensus Egr-1 binding site (5′-GCGGGGGCG-3′). Transcription from this site could be stimulated in C6 glioma cells in response to phorbol ester treatment. The induction of a “new” site (Pi) with phorbol ester also suggested a mechanism to explain the discrepancy between the reported “starts” for the ovarian versus brain cDNAs. A hybrid luciferase gene directed by rat FGF-2 5′-flanking DNA (−1,058/+54) was expressed in rat glioma C6, heart myoblast H9c2, and human astrocytoma U87-MG cells after gene transfer. The level of transfected FGF-2 promoter activity was higher in glial cells (C6 and U87-MG) compared with nonglial (H9c2) cells. Also, expression of this hybrid FGF-2/luciferase gene was increased in response to phorbol ester or serum treatment of C6 cells. Deletion analysis revealed the presence of both positive and negative regulatory regions that are involved in the transcriptional control of rat FGF-2 gene by mitogenic stimuli.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 39 (1998), S. 5253-5259 
    ISSN: 1089-7658
    Quelle: AIP Digital Archive
    Thema: Mathematik , Physik
    Notizen: The Bertrand's theorem is extended, i.e., closed orbits still may exist for central potentials other than the power law Coulomb potential and isotropic harmonic oscillator. It is shown that for the combined potential V(r)=W(r)+b/r2(W(r)=arν), when (and only when) W(r) is the Coulomb potential or isotropic harmonic oscillator, closed orbits still exist for suitable angular momentum. The correspondence between the closeness of classical orbits and the existence of raising and lowering operators derived from the factorization of the radial Schrödinger equation is investigated. © 1998 American Institute of Physics.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 752 (1995), S. 0 
    ISSN: 1749-6632
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Allgemeine Naturwissenschaft
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    Journal of the American Chemical Society 111 (1989), S. 2321-2322 
    ISSN: 1520-5126
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    [s.l.] : Macmillian Magazines Ltd.
    Nature 431 (2004), S. 811-818 
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] Glutamate transporters are integral membrane proteins that catalyse the concentrative uptake of glutamate from the synapse to intracellular spaces by harnessing pre-existing ion gradients. In the central nervous system glutamate transporters are essential for normal development and function, and ...
    Materialart: Digitale Medien
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  • 6
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] Na+/Cl--dependent transporters terminate synaptic transmission by using electrochemical gradients to drive the uptake of neurotransmitters, including the biogenic amines, from the synapse to the cytoplasm of neurons and glia. These transporters are the targets of ...
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Computational & mathematical organization theory 2 (1996), S. 171-195 
    ISSN: 1572-9346
    Schlagwort(e): organization design ; simulation ; organization modeling ; organizational analysis tools
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract Large scale and multidisciplinary engineering projects (e.g., design of a hospital building) are often complex. They usually involve many interdependent activities and require intensive coordination among actors (i.e., designers) to deal with activity interdependencies. To make such projects more effective and efficient, one needs to understand how coordination requirements are generated and what coordination mechanisms should be applied for given project situations. Our research on the Virtual Design Team (VDT) attempts to develop a computational model of project organizations to analyze how activity interdependencies raise coordination needs and how organization design and communication tools change team coordination capacity and project performance. The VDT model is built based on contingency theory (Galbraith, 1977) and our observations about collaborative and multidisciplinary work in large, complex projects. VDT explicitly models actors, activities, communication tools and organizations. Based on our extended information-processing view of organizations, VDT simulates the actions of, and interactions among actors as processes of attention allocation, capacity allocation, and communication. VDT evaluates organization performance by measuring emergent project duration, direct cost, and coordination quality. The VDT model has been tested internally, and evaluated externally through case-studies. We found three way qualitative consistency among predictions of the simulation model, of organization theory, and of experienced project managers. In this paper, we present the VDT model in detail and discuss some general issues involved in computational organization modeling, including level of abstraction of tasks and actors' reasoning, and model validation.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    [s.l.] : Macmillian Magazines Ltd.
    Nature 422 (2003), S. 527-531 
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] p53 has a role in many cellular processes through the transcriptional regulation of target genes. PAC1 (phosphatase of activated cells 1; also known as dual specificity phosphatase 2, DUSP2) is a dual threonine/tyrosine phosphatase that specifically dephosphorylates and inactivates ...
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 330-332 (Feb. 2007), p. 271-274 
    ISSN: 1013-9826
    Quelle: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Thema: Maschinenbau
    Notizen: This paper reports synthesis of hydroxyapatite nanoparticles by three precipitationmethods. Homogeneous aqueous solution of Ca(NO3)2 and H3PO4 was used as precursor solution,and NH3•H2O was precipitator. Calcium deficient hydroxyapatite nanorods were obtained byadding the precipitator into precursor solution, near stoichiometric hydroxyapatite nanoparticleswere derived from adding precursor solution into the precipitator, and smaller hydroxyapatitenanoparticles were prepared by adding precipitator and precursor solution simultaneously into areaction vessel. The stoichiometry of hydroxyapatite was mainly affected by pH at precipitationreaction process. The crystal size and shape of hydroxyapatite particles was related to Ostwaldripening. The stoichiometry and morphology of hydroxyapatite nanoparticles can be controllable byselecting suitable coprecipitation process
    Materialart: Digitale Medien
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  • 10
    ISSN: 1573-4919
    Schlagwort(e): cell division ; gene transfer ; mitogenic response
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Abstract Basic fibroblast growth factor (FGF-2) plays an important role in myocardial growth and development and in particular cardiac myocyte proliferation. FGF-2 exerts its effects by binding to cell surface receptors (FGFR-1) of the tyrosine kinase family. We have detected the presence of both long and short isoforms of FGFR-1 in embryonic and adult mouse heart. In this report, we have examined the ability of long and short FGFR-1 isoforms to signal a mitogenic response. Assessment of RNA from rat myoblast H9c2 cells by reverse transcriptase-polymerase chain reaction and RNA blotting revealed that they were deficient in transcripts corresponding to long and short FGFR-1 species. Hybrid genes containing the cDNAs coding for long and short FGFR-1 isoforms directed by the myosin light chain-2 promoter and simian virus 40 enhancer sequences, were used to transiently transfect H9c2 cells. Total tyrosine phosphorylation was increased 2.0 and 2.6 fold in H9c2 cells transfected with the long and short FGFR-1 isoforms, respectively, compared to 'control' transfected H9c2 cells. This was accompanied by a 2.1 and 2.0 fold increase in DNA synthesis, as measured by tritiated thymidine incorporation, in H9c2 cells expressing the long and short FGFR-1 isoforms, respectively. To assess effects on proliferation, H9c2 cells were stably transfected with the myosin light chain-2/FGFR-1 cDNA genes. The rate of proliferation was increased 1.6 and 3.1 fold in H9c2 cells stably expressing the long and short FGFR-1 isoforms, respectively, compared to 'control' H9c2 cells. In contrast to non transfected H9c2 cells, treatment of H9c2 cells stably expressing long FGFR-1 with FGF-2 for 24 h resulted in a slight increase (1.3 fold, p 〈 0.02) in cell number. However, a greater response (1.5 fold, p 〈 0.0005) was observed with H9c2 cells stably expressing short FGFR-1 after treatment with FGF-2. These results suggest that both long and short FGFR-1 isoforms are capable of signalling a mitogenic response.
    Materialart: Digitale Medien
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