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  • 1
    Electronic Resource
    Electronic Resource
    Die zweite Tagung der Deutschen Pharmakologischen Gesellschaft (1922)
    Springer
    Naturwissenschaften 10 (1922), S. 140-144 
    Details
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01488105
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  • 2
    Electronic Resource
    Electronic Resource
    Influence of gene dosage and autoregulation of the regulatory genes INO2 and INO4 on inositol/choline-repressible gene transcription in the yeast Saccharomyces cerevisiae (1997)
    Springer
    Current genetics 31 (1997), S. 462-468 
    Details
    ISSN: 1432-0983
    Keywords: Key words Transcriptional regulation ; Phospholipid biosynthesis ; Saccharomyces cerevisiae ; INO2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Expression of structural genes of phospholipid biosynthesis in yeast is mediated by the inositol/choline-responsive element (ICRE). ICRE-dependent gene activation, requiring the regulatory genes INO2 and INO4, is repressed in the presence of the phospholipid precursors inositol and choline. INO2 and, to a less extent, INO4 are positively autoregulated by functional ICRE sequences in the respective upstream regions. However, an INO2 allele devoid of its ICRE functionally complemented an ino2 mutation and completely restored inositol/choline regulation of Ino2p-dependent reporter genes. Low-level expression of INO2 and INO4 genes, each under control of the heterologous MET25 promoter, did not alter the regulatory pattern of target genes. Thus, upstream regions of INO2 and INO4 are not crucial for transcriptional control of ICRE-dependent genes by inositol and choline. Interestingly, over-expression of INO2, but not of INO4, counteracted repression by phospholipid precursors. Possibly, a functional antagonism between INO2 and a negative regulator is the key event responsible for repression or de-repression.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002940050231
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  • 3
    Electronic Resource
    Electronic Resource
    Fabrication of large periodic arrays of AlGaAs microdisks by laser-interference lithography and selective etching (2002)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 81 (2002), S. 592-594 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: By laser-interference lithography, reactive-ion etching, and selective wet-chemical etching using a citric acid-based solution, we have fabricated large periodic arrays of AlGaAs microdisks with periods of 4 μm and disk diameters between 1.5 and 2 μm. The arrays are characterized by temperature-dependent photoluminescence spectroscopy. Taking into account the below-threshold absorption of the quantum wells inside the disks, we get disk quality factors close to the theoretical maximum value. We demonstrate that our technique allows one also to produce one-dimensionally or two-dimensionally coupled arrays of microdisks. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1495082
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  • 4
    Electronic Resource
    Electronic Resource
    Dynamics of hydrogen-bonded liquids confined to mesopores: A dielectric and neutron spectroscopy study (1995)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 103 (1995), S. 2016-2024 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: In this paper we present and discuss experimental results on molecular mobility in propylene glycol and its three oligomers confined to the ∼100 A(ring) pores of a controlled porous glass. The objective is to elucidate the finite size effects on the dynamics of hydrogen-bonded liquids of different molecular weights but identical chemical composition. The methods of dielectric and neutron spectroscopy have been employed to investigate both the low- and high-frequency features as a function of temperature. We find that all fluids in pores separate into two distinct liquid phases. (i) molecules physisorbed at the surface which exhibit a dramatic frustration of their mobility related to a substantial positive shift of the glass transition temperature Tg by up to ΔTg≈+47 K; and (ii) relatively "free'' molecules in the inner pore space subject to only moderate retardation of the α and normal mode relaxation and substantial broadening of the distribution of relaxation times. The shift in Tg for the α process with ΔTg≈+5 K is maximal for the monomer liquid and gradually diminishes with increasing molecular weight or decreasing intermolecular hydrogen bonding. The inelastic neutron spectrum of confined propylene glycol shows the boson peak as expected in bulk strong and intermediate glass formers in the vicinity of Tg. This effect can be attributed to the finite-size induced crossover from long wave vibrations characteristic of a continuous medium to localized vibrations in a confined geometry. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.469728
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  • 5
    Electronic Resource
    Electronic Resource
    High resolution temperature and density profiles during the energy quench of density limit disruptions in Rijnhuizen tokamak project (2002)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 9 (2002), S. 3402-3412 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Measurements of the electron temperature, Te, and density, ne, during the energy quench of a major disruption showed that the onset of Te erosion in the neighborhood of the m/n=2/1 O point at the low field side (LFS) accelerates the well-known m/n=1/1 erosion of the core temperature. During this phase Te(r) is only partially flat in the region between the q=2 and the q=1 surfaces and ne(r) decreases in the core and increases inside the m/n=2/1 island. Immediately after the flattening of Te(r) a large peak in Te and to a lesser extent in ne has been observed. This peak is radially localized at the q=2 radius at the LFS, is very short lived and is poloidally asymmetric. Te profiles measured by the heterodyne radiometer and the Thomson scattering agree very well up to the time Te(r) flattens but afterwards can be a factor of two different. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1489675
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  • 6
    Electronic Resource
    Electronic Resource
    The electron cyclotron absorption diagnostic at the Rijnhuizen tokamak project (1997)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 68 (1997), S. 4439-4447 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A new 20-channel electron cyclotron absorption diagnostic has been developed at the Rijnhuizen tokamak project. It is the first time the electron pressure profile in a tokamak plasma can be measured directly with a time resolution of 1 ms. The diagnostic measures simultaneously the emission and absorption of the second harmonic electron cyclotron frequencies. Microwaves are injected from the high field side and detected at the low field side in the equatorial midplane. The transmitted power is measured after a single pass through the plasma column. The absorption measurements are complicated by nonresonant losses: refraction of the injected microwaves (losses up to 100%), and scattering of microwaves by density fluctuations (losses 2%–3%). A fast algorithm has been developed to obtain a quantitative measure for these nonresonant losses. This calculation method is based on a parametrization of the experimental data. Combining the electron cyclotron absorption (ECA) measurements and the parametrization provides a reliable tool for determining the optical depth, the electron temperature, and the electron pressure. A good agreement was found between pressure and temperature profiles, measured with ECA and other diagnostics. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1148411
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  • 7
    Electronic Resource
    Electronic Resource
    Elastomeric binary phase gratings for measuring acceleration, displacement, strain, and stress (1996)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 67 (1996), S. 3310-3319 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: This article describes the fabrication and operating principles of a device suitable for measuring displacements, stresses, strains, accelerations, and forces. The device consists of an elastomeric material with a surface relief diffraction grating embossed on its surface. Mechanical compression of this element changes the way that it diffracts light. This article also describes designs and performance characteristics of simple accelerometers and pressure sensors based on these devices. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1147413
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  • 8
    Electronic Resource
    Electronic Resource
    Rutherford scattering at TEXTOR : Proceedings of the 9th topical conference on high temperature plasma diagnostics (1992)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 4583-4585 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The Rutherford scattering diagnostic at TEXTOR is used to perform temporal and spatial resolved measurements of the ion temperature. Function parametrization techniques are used for fast analysis of the complex spectra, which also contain information about the presence of impurities in the scattering volume. The (perpendicular) central ion temperature has been determined for a series of discharges, where neutral beam coinjection (hydrogen) was applied to plasmas of different densities. A temperature of 2.8 keV was found for a line-averaged electron density of 1.5×1019 m−3, decreasing monotonically for higher densities to 0.8 keV at 6.0×1019 m−3. When deuterium was used as heating beam species, scattering on a high-Z impurity, probably tungsten from the filaments of the NBI sources, gave a dominant contribution to the spectra.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1143677
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  • 9
    Electronic Resource
    Electronic Resource
    Investigation of ion sawtooth activity by Rutherford scattering : Proceedings of the tenth topical conference on high temperature plasma diagnostics (1995)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 327-329 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The Rutherford scattering diagnostic at TEXTOR has been used to investigate the time evolution of the ion velocity distribution during sawtooth activity. Coherent averaging techniques have been employed to obtain better statistics. The time evolutions of central ion and electron density were found to be strongly correlated in four out of five cases. In one case, where saturation of the sawteeth occurred, a discrepancy between the two has been found, which could be attributed to an influx of impurities towards the end of the sawtooth. Changes of about 20% in the central toroidal rotation of the bulk ions have been found during sawtooth crashes of neutral beam injected discharges, whereas no changes were found in the ohmic case. No statistically reliable statements can be made about changes in the ion temperature. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1146401
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  • 10
    Electronic Resource
    Electronic Resource
    Ion temperature measurements in tokamak plasmas by Rutherford scattering (1992)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 3359-3368 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A Rutherford scattering diagnostic has been applied at the TEXTOR tokamak to obtain spatially and temporally resolved information on the temperature of the bulk ions in the plasma. In the experimental setup, a helium atomic beam (30-keV, 12-mA equivalent current) passes vertically through the plasma core. A small part of the injected atoms is scattered elastically by the thermally moving plasma ions. The ion temperature in the scattering volume can be determined from the broadening of the energy spectrum of the scattered particles. Energy analysis of the scattered atoms is performed by a mass-selective time-of-flight analyzer detecting the particles at an observation angle which is selectable between 3° and 8°. Coincidence techniques have been successfully applied in this detector for rejection of background events triggered by detections of neutrons and gamma radiation. Ion temperature profiles were measured on a shot-to-shot basis by shifting the cross section of the diagnostic beam and the observational volume of the analyzer through the plasma. The ion temperatures measured in ohmic deuterium plasmas were found to be in reasonable agreement with those obtained from passive neutral particle analysis. Up to now, ion temperatures have been measured throughout the complete discharge with an accuracy of 8% and a time and space resolution of 100 ms and 0.10 m at a scattering angle of 7°. Deuteron density profiles could be deduced from the scattering yield measured at different radial positions in the plasma. The ratio of the isotopes, hydrogen and deuterium, was determined from their separate contributions to the spectrum of helium particles scattered on hydrogen and deuterium. Although theoretical predictions showed that the majority of the probing helium atoms loses one of its electrons during the elastic scattering process on multiply charged carbon and oxygen ions, contributions from impurities to the observed experimental spectrum are shown to appear dominant for impure plasmas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1142553
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