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61.
Proteus mirabilis is a common cause of upper urinary tract infections. Fimbriae-mediated adherence of this organism to urinary tract epithelium and invasion of host cells are factors thought to be important in its pathogenesis. We have assessed the effect of growth in serum, blood, and urine on the ability of P. mirabilis 7570 to adhere to and invade in vitro the cell line EJ/28, derived from a human urinary tract tumour, and to express nonagglutinating fimbriae (NAF). Proteus mirabilis was capable of adhering to EJ/28 cells to varying degrees depending upon the growth conditions used. It was invasive under all conditions, except when grown in urine, and was found to be particularly so when serum or blood was present in the media. Expression of NAF occurred under all growth conditions examined and was limited only by a decrease in temperature.  相似文献   
62.
This paper details a new orthogonal-frequency-division-multiplexing (OFDM) modulator based on the use of a pseudorandom postfix (PRP)-OFDM and discusses low-complexity equalization and channel estimation/tracking architectures. The main property of this new modulation scheme is the ability to estimate and track the channel variations semi-blindly using order-one statistics of the received signal. Compared with known cyclic prefix OFDM (CP-OFDM) pilot-symbol-assisted modulation (PSAM) schemes, the pilot overhead is avoided: The channel estimation is performed based on the exploitation of pseudorandomly weighted postfix sequences replacing the guard interval contents of CP-OFDM. PRP-OFDM is shown to be of advantage if the target application requires 1) a minimum pilot overhead, 2) low-complexity channel tracking (e.g., high mobility context), and 3) adjustable receiver complexity/performance trade-offs (available due to the similarities of PRP-OFDM to the zero-padded OFDM (ZP-OFDM) modulation scheme) without requiring any feedback loop to the transmitter.  相似文献   
63.
Chronic heart failure is a family affair since the spouse's quality of life is affected as much as that of the patient. This article deals with three clinical cases exploring the couple's perceptions of how the illness affected their marital relationship and how helpful the family systems nursing interventions have been. Three themes emerged from the analysis of the relationship between the evolution of the illness and the marital dynamics, and these are: a search for a balance between protectiveness/overprotectiveness, a reassessment of the marital relationship, and the adoption of new coping strategies. The family systems nursing interventions that were perceived as the most helpful were the systemic questionf1p4++ and the exploration of the couple's strengths and resources. These interventions allowed the couple to: 1) share their illness experience; 2) increase their understanding of the relationship between the illness and their marital dynamics, and 3) reflect on different ways to enhance their competence and resources in meeting with the challenges of this type of cardiac health problem.  相似文献   
64.
Thin-film transistors (TFTs) were fabricated from poly-Si crystallized by a two-step annealing process on glass substrates. The combination of low-temperature furnace annealing and high-temperature rapid thermal annealing leads to a significant improvement in the material quality. The TFTs obtained with this two-step annealing material exhibit better measured characteristics than those obtained by using conventional furnace annealing  相似文献   
65.
The excessive leakage current of polycrystalline silicon (polysilicon) TFTs, is one of the major impediments to their use in flat panel displays. The authors present new results on the use of amorphous silicon-based active gates to control the leakage current of the polysilicon TFTs. Moreover, the proposed technology, which is the first implementation of an amorphous silicon active gate recess, relies on a standard process and may ease the design rules for the realisation of TFTs  相似文献   
66.
This article extends turbo demodulation to the zero-padded OFDM (ZP-OFDM) system by accounting for the noise color and the symbols estimates correlation introduced by equalization. Resorting to realistic simulations, we show that turbo demodulation used with set partitioning labeling can significantly outperform noniterative decoding with Gray labeling. We also show that it increases the performance gap between ZP-OFDM and OFDM with cyclic prefix (CP-OFDM) relative to noniterative decoding, because it amplifies the performance gain due to the guaranteed symbol recovery of ZP-OFDM.  相似文献   
67.
This paper presents an improved sequential MAP estimator to be used as a joint source-channel decoding technique for CABAC encoded data. The decoding process is compatible with realistic implementations of CABAC in standards like H.264, i.e, handling adaptive probabilities, context modeling and integer arithmetic coding. Soft-input decoding is obtained using an improved sequential decoding technique, which allows to obtain a tradeoff between complexity and efficiency. The algorithms are simulated in a context reminiscent of H264. Error detection is realized by exploiting on one side the properties of the binarization scheme and on the other side the redundancy left in the code string. As a result, the CABAC compression efficiency is preserved and no additional redundancy is introduced in the bit stream. Simulation results outline the efficiency of the proposed techniques for encoded data sent over AWGN and UMTS-OFDM channels.  相似文献   
68.
The basic tools required for an efficient use of the recently proposed fast finite impulse response (FIR) algorithms are provided. These algorithms not only reduce arithmetic complexity but also partially maintain the multiply-accumulate structure, thus resulting in efficient implementations. A set of basic algorithms is derived, together with some rules for combining them. Their efficiency is compared with that of classical schemes in the case of three different criteria, corresponding to various types of implementation. It is shown that this class of algorithms (which includes classical ones as special cases) makes it possible to find the best tradeoff corresponding to any criterion  相似文献   
69.
PURPOSE: To evaluate the accuracy of spiral CT angiography in the diagnosis of central pulmonary embolism (PE). MATERIAL AND METHODS: A retrospective study was undertaken in a population of 90 patients who were evaluated with spiral CT angiography (acquisition: 12 to 24 s with or without strict apnea; injection of 90 cm3 of 12, 20 or 30% contrast material at a rate of 4 to 7 cm3, selective pulmonary angiography of each lung (n = 55) and/or ventilation-perfusion (VP) scanning (n = 35). RESULTS: Among the 55 patients evaluated with both spiral CT and angiography, central pulmonary embolism was excluded in 19 patients (34%), assessed in 29 patients (53%) whereas CT examination was considered as inconclusive in 7 patients (13%) due to interpretive difficulties at the level of obliquely oriented arteries and/or presence of hilar lymph nodes (sensitivity: 90.5%; specificity: 82.6%). With spiral CT, the finding of 95 central emboli (3 main, 61 lobar and 31 segmental) corresponded exactly to the angiographic findings; spiral CT enabled direct visualization of intraluminal filling defects (n = 95) whereas the angiographic recognition of PE was based on direct (n = 57) and indirect (n = 38) signs. Spiral CT angiography was more sensitive and specific than VP scanning. CONCLUSION: Spiral CT angiography appears as a sensitive and specific noninvasive method for the diagnosis of central PE.  相似文献   
70.
`Split radix? FFT algorithm   总被引:11,自引:0,他引:11  
A new N = 2n fast Fourier transform algorithm is presented, which has fewer multiplications and additions than radix 2n, n = 1, 2, 3 algorithms, has the same number of multiplications as the Raderi-Brenner algorithm, but much fewer additions, and is numerically better conditioned, and is performed `in place? by a repetitive use of a `butterfly?-type structure.  相似文献   
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