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31.
Our objective was to assess flow velocity waveforms of the portal venous system of the anemic fetus prior to and immediately following intravascular transfusion. Color-guided pulsed Doppler was used to obtain flow velocity waveforms from the fetal portal vein in 14 anemic fetuses that were transfused in utero for rhesus alloimmunization The portal vein velocity pattern was defined as continuous when no change in velocity during the cardiac cycle was noted. It was defined as pulsatile when a deflection of the wave was present. The flow velocity waveforms were quantified by using the ratio between the peak (highest, H) and the nadir (lowest, L) velocities (H/L ratio). Fourteen intravascular transfusions were performed. Gestational age ranged from 19.5 to 35 weeks (mean +/- SD, 26.7 +/- 5.3 weeks). The hematocrit ranged from 5.9 to 31.2% (mean +/- SD, 20.3 +/- 9%) prior to transfusion; after transfusion it was between 24.8 and 56.7% (mean +/- SD, 42 +/- 10.4%). In six cases (43%) the waveforms were pulsatile prior to transfusion; in the other eight (57%) they were continuous. The pulsatile pattern was present following transfusion in 13 cases (93%, p < 0.05). The mean of the H/L ratio was 1.3 +/- 0.38 prior to transfusion and 2.0 +/- 0.86 after transfusion (p < 0.05). Because the portal vein has continuous non-pulsatile flow in the normal fetus, the presence of pulsatility in the waves of six anemic fetuses (43%) may suggest portal hypertension. Compared to normal fetuses, there was an increased number of cases with pulsation, and even more so after transfusion. The pattern corresponds to findings in children with portal hypertension. 相似文献
32.
Based on successful results in animal models, it has been proposed that high-dose myeloablative therapy followed by autologous bone marrow or stem cell transplantation (ABMT/ASCT) may cure autoimmune disease. The coexistence of autoimmune disease and hematologic malignancy provides an opportunity to examine the response of autoimmune disease to ABMT or ASCT. We describe 4 patients with autoimmune disease (3 with psoriasis and 1 with rheumatoid arthritis) and hematologic malignancy. In each patient, the autoimmune disease remitted posttransplantation, but, in 4 patients with long-term followup, it recurred at 8-24 months. The earliest relapse occurred in a patient treated with interferon-alpha. Our experience suggests that a single autograft with unpurged stem cells is unlikely to cure autoimmune disease, but that other strategies building on this approach are worthy of investigation. 相似文献
33.
We present the results from tuning a PI controller and two differentiators for a three-loop steam temperature regulation system with two leading speed signals. The calculation was carried out with a numerical method using a simulation model and with the application of the authors’ version of the evolutionary optimization algorithm. 相似文献
34.
A comparison of different power electron switches for power electron converters is presented. The estimation method of steady and dynamic power loss in the switches is also described. 相似文献
35.
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37.
A. N. Tugov G. A. Ryabov V. I. Rodionov V. I. Ugnachev A. N. Smirnov V. V. Romanov M. E. Gendel’sman I. B. Kolin 《Power Technology and Engineering (formerly Hydrotechnical Construction)》2006,40(5):300-306
Problems that have arisen during tune-up of the production line for the thermal processing of solid household waste by the
method of burning in a vortical fluidized bed (principally, a new technology for Russia), and means of their solution are
presented. Investigative studies are cited.
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Translated from élektricheskie Stantsii, No. 6, pp. 20–26, August, 2006. 相似文献
38.
Yu. F. Smirnov 《Measurement Techniques》2007,50(3):293-297
Metrological characteristics of active hydrogen frequency standards are investigated on the basis of internal and external
comparisons. The stability of random changes and drift of hydrogen frequency standards and also the potential capabilities
of time scale preservation with effective consideration of systematic changes in their frequency are demonstrated.
__________
Translated from Izmeritel’naya Tekhnika, No. 3. pp. 42–45, March, 2007. 相似文献
39.
I. V. Zhuravlev D. S. Kibalov G. F. Smirnova V. K. Smirnov 《Technical Physics Letters》2003,29(11):949-950
Wavy nanostructures are formed on the ion-bombarded surface of single-crystal and amorphous silicon films prepared by various
methods. The period and depth of this structure have been determined as functions of the angle of incidence and the energy
of nitrogen ions used for the surface sputtering. A comparative analysis of SEM images of the wavy surface nanostructures
on various silicon films has been performed using a two-dimensional Fourier transform. The films of amorphous silicon obtained
by electron beam deposition and magnetron sputtering techniques are closest to single-crystal silicon films with respect to
the wavy surface nanostructure formation. 相似文献
40.
D. A. Malik K. E. Orlov A. S. Smirnov T. V. Chernoizyumskaya 《Technical Physics Letters》2003,29(6):525-527
We have studied the process of ion flux formation in a low-pressure high-frequency capacitive discharge in the presence of
a cavity on the electrode surface. If the cavity size is on the order of an electrode space charge sheath thickness, the spectrum
of ions arriving at the cavity bottom surface contains a low-energy peak. The mechanism responsible for this peak is analogous
to the hollow cathode effect in a dc discharge. 相似文献