RESUMO
For the High-Energy-Density (HED) beamline at the SASE2 undulator of the European XFEL, a hard X-ray split-and-delay unit (SDU) has been built enabling time-resolved pump/probe experiments with photon energies between 5â keV and 24â keV. The optical layout of the SDU is based on geometrical wavefront splitting and multilayer Bragg mirrors. Maximum delays between Δτ = ±1â ps at 24â keV and Δτ = ±23â ps at 5â keV will be possible. Time-dependent wavefront propagation simulations were performed by means of the Synchrotron Radiation Workshop (SRW) software in order to investigate the impact of the optical layout, including diffraction on the beam splitter and recombiner edges and the three-dimensional topography of all eight mirrors, on the spatio-temporal properties of the XFEL pulses. The radiation is generated from noise by the code FAST which simulates the self-amplified spontaneous emission (SASE) process. A fast Fourier transformation evaluation of the disturbed interference pattern yields for ideal mirror surfaces a coherence time of τc = 0.23â fs and deduces one of τc = 0.21â fs for the real mirrors, thus with an error of Δτ = 0.02â fs which is smaller than the deviation resulting from shot-to-shot fluctuations of SASE2 pulses. The wavefronts are focused by means of compound refractive lenses in order to achieve fluences of a few hundred mJâ mm-2 within a spot width of 20â µm (FWHM) diameter. Coherence effects and optics imperfections increase the peak intensity between 200 and 400% for pulse delays within the coherence time. Additionally, the influence of two off-set mirrors in the HED beamline are discussed. Further, we show the fluence distribution for Δz = ±3â mm around the focal spot along the optical axis. The simulations show that the topographies of the mirrors of the SDU are good enough to support X-ray pump/X-ray probe experiments.
RESUMO
To elucidate the potential mechanisms of anemia induced by cisplatin (CDDP) we have evaluated hemolysis, dyserythropoiesis, ferrokinetics and cytotoxicity on erythroid progenitors in 12 patients treated by a CDDP-containing combination chemotherapy and in 6 patients treated by a similar combination but without CDDP. Eight patients, from the CDDP treated group, experienced a pronounced anemia. None had signs of hemolysis. Ferrokinetic study showed a very deep and protracted decrease of 59Fe incorporation during the chemotherapy cycle and the following 2 weeks. These results, along with a normal medullary erythroblastic cellularity, suggest that CDDP induces a deep but transient erythropoiesis alteration leading to anemia in some cases.