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991.
M/G/1 type queueing systems are frequently found in the performance evaluation of communication systems. The authors develop a new solution method for these queues: their results are an alternative to both standard forms of exact analysis, and to diffusion approximations, while offering comparable computational complexity to the latter 相似文献
992.
A Nu?ez C De la Roza ML Rodrigo-Angulo W Bu?o F Reinoso-Suárez 《Canadian Metallurgical Quarterly》1997,754(1-2):1-11
This study analyses the relationship between the use of rotating instruments, the production of a smear layer and the presence of alterations to enamel microstructures. The rotating instruments used were carbide (8-12 blade) and diamond tipped (30-15 m) cutters. Cavities were made in extracted teeth. Subsequently, half the sample was analysed using the rugosimeter before and after the application of ortophosphoric acid at 35% for 15 and the other half suing a Scansion Electronic microscope (SEM). The results obtained showed on the one hand that carbide cutters leave a smoother surfacer than diamond tipped cutters, and on the other that the smear layer is eliminated better by carbide cutters compared to diamond tipped cutters. Moreover, there are no major traumatic-type alterations at the level of the enamel affecting the microstructure after the use of carbide cutters. 相似文献
993.
R Kano H Matshushiro T Watari H Tsujimoto A Hasegawa 《Canadian Metallurgical Quarterly》1997,40(9-10):335-341
To develop the molecular differentiation analysis of dermatophytes, we carried out RAPD and Southern hybridization analyses using genomic DNAs of six Arthroderma species, including A. fulvum, A. grubyi, A. gypseum, A. incurvatum, A. otae and A. racemosum. The RAPD analysis gave different band patterns specific to each of the six Arthroderma fungi. However, minor differences in the banding patterns were observed between the strains of plus (+) and minus (-) mating types of A. gypseum, A. fulvum and A. incurvatum. Southern blot analysis using a probe (1S) obtained from A. grubyi DNA gave specific bands only in the DNA samples of A. grubyi and A. incurvatum. On the other hand, Southern blot analysis using a probe (C3) obtained from A. otae DNA gave specific bands in all six Arthroderma species examined, and the size of the bands were specific to each species. These findings indicate that RAPD and Southern hybridization analyses are useful in the differentiation of these Arthroderma species. 相似文献
994.
A number of mismatch error-shaping schemes for oversampled DACs are compared. Simulation results are presented to show that such a comparison should take account of the distribution of the mismatch errors, since the pattern of errors present affects different algorithms in different ways. A scheme for improving the error tolerance of one mismatch shaping architecture is presented 相似文献
995.
O. N. Shablovskii 《Journal of Engineering Physics and Thermophysics》1997,70(2):319-327
A set of divergent forms of heat-transfer equations are presented. New laws are established that govern the behavior of the
temperature field behind the front of a strong discontinuity. Comparison of theoretical and experimental data on the propagation
of nonlinear waves in a sapphire crystal and liquid helium is carried out.
Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 70, No. 2, pp. 318–325, March–April 1997. 相似文献
996.
A Konstantinidou E Patsouris N Kavantzas PM Pavlopoulos V Bouropoulou P Davaris 《Canadian Metallurgical Quarterly》1997,142(5-6):311-316
Proliferating cell nuclear antigen (PCNA) expression has been proven to be a significant marker of cell proliferation in meningiomas, which correlates with growth rate and, as shown by several authors, possibly provides prognostic information concerning biologic behavior. However, the current method for determining PCNA labeling index (LI) is tedious and time consuming like all the nonautomated methods for evaluating cell kinetics, presenting high interobserver and interlaboratory variability and low reproducibility. In the present study, we introduce a semi-automated computer-assisted image analysis method for determining PCNA LI in 38 meningiomas, in parallel with the current nonautomated method. Image analysis technique permits unbiased cell counting, standardizes the degree of staining intensity and provides instant results. By calculating coefficient of variability, the method proved to be highly reproducible. The correlation between the results provided by the nonautomated and the semiautomated image analysis method showed a high agreement between them, with a correlation coefficient, r, of 0.82. In conclusion, we consider that image analysis contributes to the accuracy, reproducibility, and practicality of PCNA LI determination so that along with other useful parameters this significant marker may serve to predict the clinical behavior in meningiomas. 相似文献
997.
Ehrlichia spp. from human and equine sources in the northeastern Unites States were detected by PCR, isolated, and propagated in the HL-60 promyelocytic leukemia cell line. Growth of Ehrlichia from both equine and human sources was enhanced by addition of retinoic acid, which causes granulocytic differentiation of the HL-60 cells. DNA sequencing of a portion of the 16S rDNA gene supported the hypothesis that the same pathogen was responsible for both equine and human granulocytic ehrlichiosis. 相似文献
998.
999.
We studied sequential changes in electrophysiological profiles of the ipsilateral substantia nigra neurons in an in vitro slice preparation obtained from the middle cerebral artery-occluded rats. Histological examination revealed marked atrophy and neurodegeneration in the ipsilateral substantia nigra pars reticulata at 14 days after middle cerebral artery occlusion. Compared with the control group, there was no significant change in electrical membrane properties and synaptic responses of substantia nigra pars reticulata neurons examined at one to two weeks after middle cerebral artery occlusion. On the other hand, there was a significant increase in the input resistance and spontaneous firing rate of substantia nigra pars compacta neurons at 13-16 days after middle cerebral artery occlusion. Furthermore, inhibitory postsynaptic potentials evoked by stimulation of the subthalamus in substantia nigra pars compacta neurons was suppressed at five to eight days after middle cerebral artery occlusion. At the same time excitatory postsynaptic potentials evoked by the subthalamic stimulation was increased. Bath application of bicuculline methiodide (50 microM), a GABA(A) receptor antagonist, significantly increased the firing rate of substantia nigra pars compacta neurons from intact rats. These results strongly suggest that changes in electrophysiological responses observed in substantia nigra pars compacta neurons is caused by degeneration of GABAergic afferents from the substantia nigra pars reticulata following middle cerebral artery occlusion. While previous studies indirectly suggested that hyperexcitation due to deafferentation from the neostriatum may be a major underlying mechanism in delayed degeneration of substantia nigra pars reticulata neurons after middle cerebral artery occlusion, the present electrophysiological experiments provide evidence of hyperexcitation in substantia nigra pars compacta neurons but not in pars reticulata neurons at the chronic phase of striatal infarction. 相似文献
1000.
Tamasevicius A. Cenys A. Mykolaitis G. Namajunas A. Lindberg E. 《Electronics letters》1997,33(24):2025-2026
The authors present three different examples demonstrating the possibility of synchronising hyperchaotic oscillators via a single variable 相似文献