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  • 1
    Electronic Resource
    Electronic Resource
    Photon recycling system for multiposition tangential Thomson 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. 501-503 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Multiposition tangential Thomson scattering makes it possible to measure the profiles of the local drift velocity and current density of a tokamak plasma. To achieve a reasonably small observational error (20%) a high photon yield is required. In this paper we propose an optical system to increase the photon yield by about a factor of 7. Photons from a pulsed ruby laser are captured in a ring cavity by means of an electro-optical switch. The trapped laser beam recirculates about 14 times through the sampling volume which is part of the cavity, increasing the laser energy of 25 J to an effective energy of about 140 J. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1146330
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  • 2
    Electronic Resource
    Electronic Resource
    A high resolution multiposition Thomson scattering system for the Rijnhuizen Tokamak Project (1997)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 68 (1997), S. 3380-3392 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A high resolution multiposition Thomson scattering setup to measure the electron temperature (Te) and density (ne) of a hot plasma is described. The system is operational at the Rijnhuizen Tokamak Project. Light from a high power pulsed ruby laser is scattered by the free plasma electrons and relayed to a Littrow polychromator for spectral analysis. The spectrally and spatially resolved light is detected by a GaAsP photocathode. The two-dimensional image is intensified and recorded with a charge-coupled device camera.Te in the range of 50 eV–6 keV can be measured at 115 spatial elements of 2.6 mm length along the laser beam. The observation error is 〈6% at ne=2×1019 m−3 and smaller for higher ne. The high resolution and accuracy enabled the observation of small scale structures in Te and ne. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1148345
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  • 3
    Electronic Resource
    Electronic Resource
    Error analysis of Rijnhuizen tokamak project Thomson scattering data (1999)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 70 (1999), S. 1999-2011 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: At the Rijnhuizen tokamak project a double pulse multiposition Thomson scattering diagnostic has been operational since 1996. It has been installed for the study of small scale structures in electron temperature (Te) and density (ne). This diagnostic measures Te and ne with high spatial resolution (3 mm full width at half maximum, i.e., 2% of the minor radius) and high accuracy (3%–4% of Te and 2%–3% of ne in the range of 50 eV–6 keV and ne=5×1019 m−3.) In this article an extensive error analysis is performed on both statistical and systematic deviations. It is found that the instrument function of the detection branch has a smoothing effect on the noise. This reduces the statistical error on the Te and ne measurements on each spatial position, because the resolution of the instrument is oversampled. The long tail of the instrument profile of the entire diagnostic has a significant effect on the systematic deviations in the Te and ne determination. However, it does not affect the relative size of the small scale structures on Te and ne, and for this this reason does not hamper the study of these structures. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1149702
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  • 4
    Electronic Resource
    Electronic Resource
    High-resolution multiposition Thomson scattering for the TJ-II stellarator : Proceedings of the 12th topical conference on high temperature plasma diagnostics (1999)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 70 (1999), S. 763-767 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: In this article, the recent installed multiposition Thomson scattering (TS) of the TJ-II stellarator is presented. Light from a pulsed ruby laser is scattered by the free electrons of the plasma and led to a spectrometer for spectral analysis. The Doppler broadened spectrum of the scattered light is analyzed with a spectrometer in the Littrow configuration, detected with a GaAsP image intensifier and recorded with two intensified charged coupled device cameras. Values of the electron temperature (Te) in the range of 50 eV up to 4 keV can be measured at 160 spatial elements of 2.25 mm along a chord of 360 mm. First results show that the observational error for Te is close to the expected error of ∼10% at an electron density (ne) of 1×1019 m−3 using a laser energy of 8 J. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1149399
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  • 5
    Electronic Resource
    Electronic Resource
    Structures in Te profiles: High resolution Thomson scattering in the Rijnhuizen tokamak project : Proceedings of the 12th topical conference on high temperature plasma diagnostics (1999)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 70 (1999), S. 995-997 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: In the Rijnhuizen tokamak project, the double pulse multiposition Thomson scattering diagnostic is in full operation. Its high spatial resolution enables the measurement of small scale structures in Te, ne, and pe. Thomson scattering profiles during an ordinary sawtooth crash show the displacement of the hot core in great detail. Measurements on off-axis sawtoothing plasmas show that a small central part remains unaffected. Filaments are observed in plasmas which show a transient central temperature rise in response to fast edge cooling. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1149366
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  • 6
    Electronic Resource
    Electronic Resource
    Double pulse Thomson scattering system at RTP : Proceedings of the eleventh topical conference on high temperature plasma diagnostics (1997)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 68 (1997), S. 721-724 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: In this article a double pulse multiposition Thomson scattering diagnostic, under construction at RTP, is discussed. Light from a double pulsed ruby laser (pulse separation: 10–800 μs, max. 2×12.5 J) is scattered by the free electrons of the tokamak plasma and relayed to a Littrow polychromator for spectral analysis. The spectrally resolved light is recorded by two ICCD detectors. Simulations show that the system sensitivity will be such that electron temperatures in the range of 100 eV–7 keV can be determined with an accuracy as good as 2%–3% for electron densities of 1020 m−3, with a spatial resolution down to 2.6 mm. With this diagnostic the dynamics of small scale structures in the electron temperature profile will be studied. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1147685
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  • 7
    Electronic Resource
    Electronic Resource
    Determination of the local current density by means of tangential Thomson scattering: Experimental setup, feasibility test, and preliminary observations (1989)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 60 (1989), S. 2673-2679 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The local current density is one of the most important and most difficult parameters to be determined in a thermonuclear plasma. An experimental setup to measure the local electron drift velocity and thus, the current density, by means of tangential Thomson scattering, is presented. The drift velocity of the plasma causes a small wavelength shift of the scattered spectrum, which will be proportional to the local current density if toroidal ion rotation can be neglected. The ratio between the drift velocity and the mean thermal electron velocity is small, typically ∼0.05. A 20-channel high transmission polychromator has been constructed to observe the electron temperature and density within an accuracy of 1% and the drift velocity within 20% at a plasma density ne≈5×1019 m−3 and a laser energy of 7 J. A feasibility test on radial scattering shows that there is good agreement between the accuracy obtained from quantum statistics and observations, respectively. The high transmission and relatively high resolution of the polychromator enable the observation of irregularities in the velocity distribution which should be taken into account in the determination of the drift velocity. Preliminary observations in the tangential direction demonstrate the possibility to determine the drift velocity by a single laser shot. At ne ≈6×1019 m−3 and a laser energy of 3.5 J in the scattering volume a wavelength shift of −2.5±0.5 nm has been recorded corresponding to jφ≈1×107 A/m2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1140692
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  • 8
    Electronic Resource
    Electronic Resource
    Polycistronic transcription and editing of the mitochondrial small subunit (SSU ) ribosomal RNA in Dictyostelium discoideum (1999)
    Springer
    Current genetics 36 (1999), S. 55-61 
    Details
    ISSN: 1432-0983
    Keywords: Key words Mitochondria ; Ribosomal RNA ; RNA editing ; Polycistronic transcription
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Northern analyses and reverse transcription-polymerase chain reaction (RT-PCR) experiments were performed on total RNA of Dictyostelium discoideum. The mitochondrial genes encoding the small subunit ribosomal RNA (SSU), cytochrome b (CYTB) and subunit 3 of the NADH dehydrogenase (ND3) were found to be co-transcribed. Further post-transcriptional processing resulted in a dicistronic transcript for CYTB and ND3, and a monocistronic SSU transcript. Markedly higher steady state transcript levels were detected for the mature SSU ribosomal RNA. A comparison of the SSU cDNA sequence with the mitochondrial DNA sequence of the SSU gene revealed C-to-U substitutional editing of the SSU ribosomal RNA at a single site, as a consequence of which the cDNA contained a PvuII site not present in the genomic DNA. The editing was shown to be highly efficient and to occur in the primary transcript before the release of the mature mRNA, rRNA and tRNAs. It is suggested that the editing may be required for normal pseudoknot formation in the 530 loop of the RNA and thus is important for efficient, accurate translation in the mitochondria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002940050472
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  • 9
    Electronic Resource
    Electronic Resource
    Accuracy of endorectal ultrasound after preoperative radiochemotherapy in locally advanced rectal cancer (1999)
    Springer
    Surgical endoscopy and other interventional techniques 13 (1999), S. 980-984 
    Details
    ISSN: 1432-2218
    Keywords: Key words: Rectal cancer — Preoperative staging — Endorectal ultrasound — Preoperative radiochemotherapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objectives: Factors limiting the accuracy of endorectal ultrasound in staging, locally advanced primary rectal cancer after preoperative neoadjuvant radiochemotherapy (RCT) were evaluated. Methods: Patients (n= 84) with initial locally advanced rectal cancer (uT3/uT4) undergoing R0 resection were investigated after preoperative treatment that combined radiotherapy up to 45 Gy with two cycles of chemotherapy (5-FU and leucovorin on d 1–5 and 22–28). At 4 to 6 weeks after completion of RCT and before tumor resection, preoperative endoluminal ultrasound was performed. Results: The accuracy to predict the depth of tumor infiltration (T-category) was found to correlate with downstaging. The T-category was correctly staged before surgery in 15 of the 51 responders (29%) and in 27 of 33 nonresponders (82%), whereas misinterpretation occurred in 36 of the responders (71%) and in 6 of the nonresponders (18%) (p 〈 0.001). Neither tumor distance from anal verge nor tumor location correlated with the staging accuracy. Lymph node involvement was correctly assessed in 48 patients (57%). Wall invasion was correctly ascertained in 42 patients (50%), with under estimation in 11 patients (13%) and overestimation in 31 patients (37%). Conclusions: After radiochemotherapy, endosonography does not provide a satisfactory accuracy for preoperative staging of rectal cancer. New interpretation and diagnostic criteria are needed for the prediction of treatment response.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004649901151
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  • 10
    Electronic Resource
    Electronic Resource
    Influence of different dietary proteins on plasma growth hormone in rats (1988)
    Springer
    European journal of nutrition 27 (1988), S. 229-235 
    Details
    ISSN: 1436-6215
    Keywords: growth hormone ; casein ; soy protein ; endocrine response ; hypercholesterolemia ; Wachstumshormon ; Casein ; Sojaprotein ; endokrine Reaktion ; Hypercholesterinämie
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Casein, im Gegensatz zu pflanzlichen Proteinen, führt bei einigen Tierspezies zu Hypercholesterinämie. Dies könnte mit einer Änderung des Hormonstatus einhergehen. Neben anderen Hormonen hat das Wachstumshormon (GH) eine wichtige Rolle in der Regulation des Cholesterinstoffwechsels. Ein GH-Mangel führt zu Hypercholesterinämie. Diese Untersuchung zeigt, daß die zyklischen Schwankungen der GH-Spiegel durch die Art des Nahrungsproteins beeinflußt werden. Die GH-Mittelwerte und die errechnete Fläche unter den GH-Spiegeln über 4 Stunden sind bei Caseingefütterten Tieren höher als bei Sojaprotein-gefütterten Tieren. Höhere GH-Spiegel in Casein-gefütterten im Vergleich zu Gluten-gefütterten Tieren wurden bereits beobachtet. Unsere Daten unterstützen also die These, daß verschiedene Nahrungsproteine zu unterschiedlichen endokrinen Antworten führen. Da aber niedrige GH-Spiegel die Voraussetzung für die Ausbildung einer Hypercholesterinämie sind, können die beobachteten Unterschiede nicht die Basis für die Ausprägung einer Casein-induzierten Hypercholesterinämie sein.
    Notes: Summary Dietary casein, compared to vegetable protein, causes hypercholesterolemia in some animal species. This may be associated with a change of hormonal status. Among others, GH has an important impact on cholesterol metabolism; GH deficiency results in hypercholesterolemia. This paper shows that the rhythmic variation of GH levels in rats is differently affected by different dietary proteins. Within a 4-h observation period overall mean values and integrated areas under the GH levels plotted against time are higher with casein as compared to soy protein. Secretory GH peak values are lower than reported before for chow-fed rats. These observations support the idea that different dietary proteins cause a different endocrine response. As GH levels are higher with casein, while lower levels would be expected to be associated with hypercholesterolemia, the observed differences are obviously of less relevance for the expression of casein-induced hypercholesterolemia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02019511
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