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121.
OBJECTIVE: To assess the role of DNA ploidy as a predictor of radioresistance in T1 glottic carcinoma. DESIGN: Case-control study. Flow cytometric DNA ploidy measurements were performed on formalin-fixed paraffin-embedded tumor specimens from 15 patients with T1 glottic laryngeal carcinomas in whom radiotherapy had failed and from a matched group of 15 patients in whom an identical radiotherapy regimen was curative. Analysis of DNA content was performed blind to outcome of treatment. SETTING: Academic tertiary referral medical center. PARTICIPANTS: Thirty patients with clinically staged T1, N0, M0 glottic carcinoma. INTERVENTION: All patients received radiation to the larynx through opposed lateral ports at a total dose of 64 to 70 Gy. RESULTS: Ten diploid and five aneuploid histograms were found in the resistant group, and six diploid and nine aneuploid histograms were found in the radiosensitive group. This difference was not statistically significant. A trend toward a higher relapse rate after radiotherapy (62.5%) among patients with diploid tumor compared with those with aneuploid tumor (35.7%) was noted. CONCLUSIONS: DNA ploidy did not predict response to radiotherapy in patients with T1 glottic cancer, probably because of the small number of patients. A trend toward lower risk of local recurrence after radiotherapy in aneuploid tumors was noted. A larger prospective study is needed to assess the value of DNA ploidy in the treatment of early laryngeal cancer.  相似文献   
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Trapping of net positive charge at low gate stress voltage, and of net negative charge at high gate stress voltage, is observed through changes in the gate-to-drain capacitance of the stressed junction. These observations can be explained in terms of electron trapping, hole trapping, and generation of acceptor-like interface states located in the upper half of the bandgap. Channel shortening is also observed and found to exhibit a logarithmic time dependence  相似文献   
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A neural network controller for trajectory control of robotic manipulators that is used not to internalize the inverse dynamic model of the controlled object but to compensate only the uncertainties of the robotic manipulator is presented. Its performance is compared with that of the conventional adaptive scheme. The results show the ability of the neural network controller to adapt to unstructured effects. A learning method for the neural network compensator with true teaching signals is shown. The tracking error of the robotic manipulator was greatly reduced when this controller was used  相似文献   
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The density of molten Pb–Bi eutectic is measured by the pycnometer method in a temperature range of 410–726 K. The confidence of error of measurement, made up by the systematic and random components, does not exceed 0.1%. The experimental results are compared with the experimental data on the density of a liquid lead–bismuth alloy of eutectic composition available in the literature.  相似文献   
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Shape memory properties of Ni-Ti based melt-spun ribbons   总被引:1,自引:0,他引:1  
Shape-memory properties of equiatomic NiTi, Ni45Ti50Cu5, and Ni25Ti50Cu25 ribbons made by melt spinning have been studied by temperature inducing the martensitic transformation under constant tensile loads. Recoverable strains above 4 pct can be obtained under ∼100 MPa loads for the NiTi and Ni45Ti50Cu5 ribbons, transforming to B19’ martensite. The B19 martensite is formed in the Ni25Ti50Cu25 ribbon after crystallization, and according to the lowering in transformation strain as Cu content increases, the recoverable strain is close to 2.5 pct for ∼150 MPa load. The transformation temperatures exhibit a linear dependence on the applied stress, which can be quantitatively described by means of a Clausius-Clapeyron type equation. The NiTi and Ni45Ti50Cu5 ribbons exhibited some degree of two-way shape-memory effect (TWSME) after thermomechanical cycling. Texture analyses performed on the different ribbons allow us to better understand the transformation strains obtained in each ribbon. The amounts of shape-memory effect (SME) and nonrecoverable strain shown by the studied ribbons are of the same order as those already observed in bulk materials, which makes melt spinning an ideal substitute to complicated manufacturing processes if really thin samples are needed. However, applicable stresses in melt-spun ribbons are limited by a relatively “premature” brittle fracture caused by irregularities in ribbon thickness.  相似文献   
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Under serum-free conditions the beta-glucan receptor of mouse macrophages mediates phagocytosis of beta-1,3-D-glucan-coated microbeads (diameter 2 microns). IFN-gamma increases the phagocytic function of the beta-glucan receptor in a dose-dependent manner, giving the plateau level at 100 U/ml. Maximum activity appears 9 h after addition of IFN-gamma to the cells. The effect disappears within 24 h. The effect of IFN-gamma may be a result of augmented receptor synthesis since treatment with cycloheximide reduces the phagocytosis. IL-1 also increases the phagocytic function of the beta-glucan receptor giving a dose-dependent response and with the plateau level reached at 10 U/ml. Maximum activity is found 4 h after addition of IL-1 to macrophages. The effect disappears within 24 h. TNF does not alter the phagocytic function of the beta-glucan receptor, but TNF together with IL-1 prolongs the effect of IL-1. PGE2 reduces the phagocytic function of the beta-glucan receptor. Maximum reduction is achieved with 8 ng/ml. Time-course studies show the lowest phagocytic activity 9 h after addition of PGE2 to the cells.  相似文献   
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This paper describes the distributed system, network and software architecture, the application development environment, the performance, and the early lessons learned on the ATM LAN testbed Mercuri established at the Honeywell Technology Center, to develop distributed multimedia technologies for real-time control applications. We have developed a client-server-based software architecture on Sun Sparcstation-2s connected by a Fore Systems' ASX-100 ATM switch, with video processing handled by Parallax's X Video cards. The architecture enables network-transparent applications and provides simple primitives for multimedia capture, display, transmission, storage, and retrieval. A real-time multimedia-in-the-loop control application was developed as the vehicle for testing the capabilities and performance of the network. Our test measurements focus on the end-user-level performance metrics such as message throughput and round-trip delay as well as video-frame jitter under no-load and load conditions. Our results show that the maximum burst throughput that can be supported at the user level is 48 Mb/s using AAL 5, while round-trip delays for 4-kbyte messages are about 3 ms. Our experience reveals a number of performance bottlenecks and open issues in using commercial ATM switches for practical applications. Our conclusions are outlined  相似文献   
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