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  • 1
    ISSN: 0014-5793
    Keywords: Bacterial sensor protein ; Phytochrome phylogeny ; Phytochrome sensor protein ; Phytochrome, mode of action
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0014-5793
    Keywords: Moss photoreceptor ; Physcomitrella patens (Hedw.) ; Physcomitrella phytochrome ; Phytochrome phylogeny ; Phytochrome sequence
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0649
    Keywords: 42.60 ; 42.55 ; 42.65
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We systematically investigate the difference between both actively and passively mode-locked lasers with Gain-at-the-End (GE) and Gain-in-the-Middle (GM) at the example of Nd:YLF lasers. The GE laser generates pulse widths approximately three times shorter than a comparable GM cavity. This is due to enhanced Spatial Hole Burning (SHB) which effectively flattens the saturated gain and allows for a larger lasing bandwidth compared to a GM cavity. We first investigate enhanced SHB by measuring the cw mode spectrum, where we have observed that the mode spacing in GE cavities depends primarily on the crystal length. This was also confirmed for a Nd:LSB crystal, where the pump absorption length was significantly shorter than the crystal length. In mode-locked operation, pulse widths of 4 ps for passive mode locking and 5 ps for active mode locking are demonstrated with GE cavities, compared to 11 ps for passive and 17 ps for active mode locking with GM cavities. Additionally, the time-bandwidth product for the GE cavity is approximately twice the ideal product for a sech2 pulse shape and cannot be improved by dispersion compensation alone, while the GM cavity has nearly ideal time-bandwidth-limited performance. The results for the GM cavity compare well to existing theories taking into account the added effect of pump-power-dependent gain bandwidth which increases the bandwidth of Nd: YLF from 360 to 〉 500 GHz. In a following paper [1] (called Part II) a rigorous theoretical treatment of the effects due to SHB will be presented.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 61 (1995), S. 569-579 
    ISSN: 1432-0649
    Keywords: 42.60 ; 42.55 ; 42.65
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In Part I of this paper [1] experimental results were presented and discussed. In this part, we investigate theoretically the dynamics of end-pumped solid-state lasers due to enhanced spatial hole burning. This becomes possible by a fast numerical implementation of the saturated gain in the presence of strong spatial hole burning that allows to treat the multimode case for an arbitrary pumping level. We find for a wide range of laser parameters that the mode spacing of the cw running modes is essentially determined by the length of the gain medium and only weakly depends on the absorption depth of the pump transition. It is shown that spatial hole burning can lead to a completely flat saturated gain profile over half of the gain bandwidth. In mode-locked lasers, the flat gain due to spatial hole burning results in shorter pulses. But the pulses are neither Gaussian-nor sech-shaped as they are in actively or passively mode-locked lasers without spatial hole burning. Further, we show that soliton-like pulse shaping can be used to restore a transform-limited sech-shaped pulse in an end-pumped solid-state laser while exploiting the full gain bandwidth of the laser material.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 55 (1977), S. 351-353 
    ISSN: 1432-1440
    Keywords: Plasma renin activity ; Long-term treatment ; Propranolol ; Essential hypertension ; Propranolol ; Essentielle Hypertonie ; Plasmareninaktivität ; Langzeitbehandlung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 17 Patienten im Alter von 40±9 Jahren mit essentieller Hypertonie wurden mit Propranolol als Monotherapie oral in Dosen von 120, 160 oder 240 mg pro die behandelt. Nach 4wöchiger Behandlung konnten der Blutdruck und die Herzfrequenz statistisch signifikant gesenkt werden und blieben auch bei Fortsetzung der Therapie nach insgesamt 6 Monaten unverändert. Die Plasmareninaktivität betrug vor Behandlungsbeginn 5,7±6,3 ng/ml/h und sank nach 4wöchiger Behandlung auf 1,8±1,3 ng/ml/h ab. 5 Monate später stieg das Plasmarenin im Durchschnitt wieder auf 5,0±0,9 ng/ml/h an. Der erneute Anstieg war ebenfalls statistisch signifikant zu sichern. Von den 17 Patienten hatten nach 6 monatiger Therapie noch 7 (41%) eine niedrigere Plasmareninaktivität als vor Behandlungsbeginn. Davon lagen aber nur 3 (18%) unter dem Wert, der nach 4wöchiger Behandlungsdauer bestimmt wurde. Aus den genannten Befunden wird geschlossen, daß der Wiederanstieg der Plasmareninaktivität möglicherweise ein reaktiver Mechanismus auf die langzeitige Blutdrucksenkung ist. Die Erniedrigung der Plasmareninaktivität nach Kurzzeitbehandlung mit Propranolol kann nicht als ein Mechanismus für den antihypertensiven Effekt dieses Medikaments bei der Langzeitbehandlung angesehen werden.
    Notes: Summary 17 patients (40±9 years) with essential hypertension were included in the study. A monotherapy of 120, 160 or 240 mg propranolol per day was administered orally according to the antihypertensive effect. Four weeks after treatment, blood pressure and heart rate showed a statistically significant decrease and remained unchanged over a period of six months. Plasma renin activity decreased significantly from 5.7±6.3 ng/ml/h at the beginning of the study to 1.8±1.3 ng/ml/h after 4 weeks. 5 months later however plasma renin activity increased again to 5.0±0.9 ng/ml/h. The difference was statistically significant. From 17 patients 7 (41%) had lower levels of plasma renin activity after 6 months treatment when compared with pretreatment values. In only 3 patients (18%) was plasma renin activity lower after 6 months than after four weeks. We conclude that the increase in plasma renin activity is a reactive mechanism to the reduced blood pressure under long-term conditions. The decrease of plasma renin activity in short-term treatment of essential hypertension is not a mechanism responsible for the antihypertensive effect of propranolol during long-term treatment.
    Type of Medium: Electronic Resource
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