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Biomedical subjects

F Lindner

Publications and source records attributed to F Lindner.

9 recordsLinked to original sources
PubMed2005

Attosecond double-slit experiment.

A new scheme for a double-slit experiment in the time domain is presented. Phase-stabilized few-cycle laser pulses open one to two windows (slits) of attosecond duration for photoionization. Fringes in the angle-resolved energy spectrum of varying visibility depending on the degree of which-way information are measured. A situation in which one and the same electron encounters a single and a double slit at the same time is observed. The investigation of the fringes makes possible interferometry on the attosecond time scale. From the number of visible fringes, for example, one derives that the slits are extended over about 500 as.

Journal Article↗
PubMed2005

Intragastric acidity during treatment with esomeprazole 40 mg twice daily or pantoprazole 40 mg twice daily--a randomized, two-way crossover study.

BACKGROUND: Patients with severe or complicated reflux disease may require higher than standard doses of a proton pump inhibitor for sufficient acid suppression. AIM: To test the hypothesis that esomeprazole 40 mg twice daily is superior to pantoprazole 40 mg twice daily in lowering intragastric acidity. METHODS: In a randomized, single-blinded, two-way crossover study, healthy subjects received esomeprazole 40 mg twice daily or pantoprazole 40 mg twice daily orally for five consecutive days. Continuous ambulatory 24-h intragastric pH was recorded on day 5 of each treatment. RESULTS: Thirty subjects were analysed. Esomeprazole provided significantly higher intragastric pH-values over the 24-h period [median intragastric pH 6.4 for esomeprazole and 5.1 for pantoprazole (P < 0.00005)]. Intragastric pH > 4 was maintained for 21.1 h with esomeprazole and 16.8 h with pantoprazole (P < 0.0001). An intragastric pH > 4 for more than 16 h was achieved in 96.7 and 56.7% of subjects, respectively (P = 0.0002). During night-time the proportion of time with intragastric pH > 4 was 85.4% with esomeprazole and 63.6% with pantoprazole (P = 0.0001). Nocturnal acid break through occurred less frequently on esomeprazole. CONCLUSIONS: Esomeprazole 40 mg twice daily provides better and more consistent intragastric acid control than pantoprazole 40 mg twice daily.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2004

Nonsequential double ionization at the single-optical-cycle limit.

We report differential measurements of Ar++ ion momentum distributions from nonsequential double ionization in phase-stabilized few-cycle laser pulses. The distributions depend strongly on the carrier-envelope (CE) phase. Via control over the CE phase one is able to direct the nonsequential double-ionization dynamics. Data analysis through a classical model calculation reveals that the influence of the optical phase enters via (i) the cycle dependent electric field ionization rate, (ii) the electron recollision time, and (iii) the accessible phase space for inelastic collisions. Our model indicates that the combination of these effects allows a look into single cycle dynamics already for few-cycle pulses.

Journal Article↗
PubMed2004

Gouy phase shift for few-cycle laser pulses.

We measured for the first time the influence of the Gouy effect on focused few-cycle laser pulses. The carrier-envelope phase is shown to undergo a smooth variation over a few Rayleigh distances. This result is of critical importance for any application of ultrashort laser pulses, including high-harmonic and attosecond pulse generation, as well as phase-dependent effects.

Journal Article↗
PubMed2003

Measurement of the phase of few-cycle laser pulses.

For the shortest pulses generated to date, the amplitude of the electromagnetic wave changes almost as rapidly as the field oscillates. The temporal variation of the field, which directly governs strong-field interactions, therefore depends on whether the maximum of the pulse amplitude coincides with that of the wave cycle or not, i.e., on the phase of the field with respect to the pulse envelope. It is demonstrated that the direction of electron emission from photoionized atoms can be controlled by varying the phase of the field, providing for the first time a tool for its accurate determination. Directing fast electron emission to the right or to the left with the light phase constitutes a new kind of coherent control.

Journal Article↗
PubMed1988

[Surgery of varicose veins. Late results in relation to vessel morphology].

A survey of the literature on the long-term results of surgical treatment for varicose veins is given. The recurrence of varicose veins after operative treatment is shown to result from inadequate surgical technique and other causes. Vascular-morphological data indicating possible deterioration of long-term results if not considered sufficiently are presented. The main requirements for good long-term results are (1) adequate diagnosis and (2) meticulous surgical technique.

Follow-Up Studies↗
PubMed1986

[Entrapment and cystic degeneration of the adventitia as a cause of occlusion of the popliteal artery].

The entrapment syndrome and the cystic adventitial degeneration of the popliteal artery are diseases affecting relative young patients. Four cases of entrapment and one case of cystic degeneration are demonstrated. In one patient also an entrapment of the popliteal vein is demonstrated. In all patients the outcome of vascular reconstruction was good. For the entrapment syndrome the posterior approach is prefered.

Adult↗