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41.
OBJECTIVE: Our purpose was to evaluate the feasibility of intrapartum fetal pulse oximetry, the distribution of fetal oxygen saturation values, and the relationship with the neonatal outcome in a population with an abnormal fetal heart rate. STUDY DESIGN: A prospective multicenter observational study was performed from June 1994 to November 1995. Fetal oxygen saturation was continuously recorded with use of a Nellcor N-400 fetal pulse oximeter in case of an abnormal fetal heart rate during labor. Simultaneous readings of fetal oxygen saturation and fetal blood analysis were obtained at inclusion and before birth. Feasibility, adverse effects, distribution of fetal oxygen saturation values, and relationship with neonatal outcome were assessed. RESULTS: One hundred seventy-four patients were included. From 172 attempted sensor placements, the procedure was impossible in three cases and fetal oxygen saturation values were obtained in 164 cases (95.3%). Physicians considered sensor placement an easier task than an attempt at fetal blood analysis (easy in 87.5% vs 78.9% for fetal blood analysis, p = 0.03). The mean reliable signal time (+/- SD) was 64.7% +/- 32% during the first stage. There were no serious adverse effects in the study population. The mean fetal oxygen saturation during the first stage of labor was 42.2% +/- 8.0% (10th to 90th percentile range 30% to 53%). Fetal oxygen saturation was significantly correlated with scalp pH (r = 0.29, p = 0.01) but not with neonatal umbilical artery pH or gas values. There was a significant association between low fetal oxygen saturation (< 30%) and poor neonatal condition. CONCLUSION: The feasibility of fetal pulse oximetry is satisfactory in clinical practice. It is easy to use and provides a fair rate of recorded values, even in a population with suspicion of fetal distress. A low fetal oxygen saturation is significantly associated with an abnormal neonatal outcome.  相似文献   
42.
43.
For the first time, a direct optically injection-locked oscillator based on the Esaki-Tsu effect in superlattices is reported. The microwave output power is -7 dBm at 20 GHz with an optical input power of -10 dBm at a wavelength of 1.3 μm  相似文献   
44.
介绍了邯钢200万t链箅机-回转窑酸性氧化球团生产线的工艺特点和主要设备,以及建成投产后试生产的有关情况。通过周密的部署和安排,该生产线实现了40天快速达产的目标。  相似文献   
45.
多时滞Lotka-Volterra互惠系统周期正解的存在性   总被引:5,自引:0,他引:5  
用重合度理论研究具时滞非自治Lotka-Volterra互惠系统,获得了周期正解的存在性,推广了Gopalsamy及He(1997)的结果。  相似文献   
46.
The Mn0.23Ga1.85S3 phase belongs to the solid solution ф0, stable at low temperature in the Ga2S3MnS system. It is hexagonal superstructure of the wurtzite, with the Ga2S3α′ type (a = 6.397 A?; c = 18.027 A?Z = 6; space groupe P61 or P65). Its crystal structure has been refined by the least squares method to a final R = 0.06 with 323 independant reflections. This structure is closely related to Ga2S3 α described by Hahn and Frank, and differs only by the partial occupation of the vacant metal site of Ga2S3 by Mn atoms in statistical disorder.  相似文献   
47.
论述引进德国SMS连铸机大包托臂液压缸存在的寿命短问题,分析设计制造缺陷.通过增大缸头密封支持面、(φ600)内圆孔倒角、再增加一道软支撑环、缸头导向部分开润滑槽、改进球杆的润滑流道、柱塞杆整体淬火等措施,消除了原来的问题.同时分析了此项改进的技术经济效果.  相似文献   
48.
Among the new semiconductor materials for telecom devices, the GaInNAs-GaAs structure presents interesting properties for low-cost applications, like high differential gain and high T/sub 0/. Another key aspect of the performance is the behavior of the GaInNAs-GaAs based lasers under high bit rate direct modulation. Here, we demonstrate the dynamic capabilities of GaInNAs-GaAs three-quantum-well ridge structure through 2.5-Gb/s directly modulated laser emission and transmission on standard fiber, in the temperature range 25/spl deg/C-85/spl deg/C. Besides transmission is demonstrated up to 10 Gb/s at 25/spl deg/C on the same fiber, without penalty and bit-error-rate floor.  相似文献   
49.
In this paper we consider two performance modelling techniques from the perspectives of model construction, generation of an underlying continuous time Markov process, and the potential for reduction in the Markov process. Such careful comparison of modelling techniques allows us to appreciate the strengths and weaknesses of different approaches, and facilitates cross-fertilization between them. In the present case we take a characteristic of one formalism, functional rates in Stochastic Automata Networks, and introduce it to the other formalism, Performance Evaluation Process Algebra. We investigate the benefits of this cross-fertilization, particularly from the perspectives of Markov process generation and reduction.  相似文献   
50.
In this work we present a bulk silicon technology platform able to cointegrate gate-all-around (GAA) MOSFETs and local SOI waveguides with pentagonal cross section. Wire diagonals of 100-800 nm are obtained using a lithographic resolution of 0.8 mum. Well-functioning triangular multigate MOSFETs are reported, and tested up to 150 degC. A significant increase is observed in the low-field mobility mu0 for small devices (Weffles500 nm), which is attributed to local volume inversion in the corners. Preliminary characterization of the optical waveguides is carried out, showing optical losses of a few dB/cm. The processing is entirely CMOS compatible, does not require access to advanced lithography equipment, and is based on a silicon bulk substrate. Thus, this technology might serve as the basis for a low-cost, high-performance optical signaling platform  相似文献   
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