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排序方式: 共有2163条查询结果,搜索用时 31 毫秒
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H Akoum C Duez H Vorng O Fahy B Wallaert AB Tonnel A Tsicopoulos 《Canadian Metallurgical Quarterly》1998,10(9):706-712
The mechanism by which specific immunotherapy exerts its beneficial effect remains unclear. Chemokines are implicated in inflammatory and allergic diseases, in particular via their ability to induce histamine release from basophils, a potential early target of rush venom immunotherapy (RVIT), In this study, the authors evaluated ex vivo regulated upon activation normal T-cell expressed and secreted (RANTES), interleukin 8 (IL-8) and monocyte chemoattractant protein 1 (MCP-1) production and mRNA expression by mononuclear cells (MNC) from nine patients undergoing a 3.5-h ultra rush treatment, before treatment at Day 0 (D0), at the end of the 3.5-h of the rush at Day 4h (D4h), at Day 15 (D15) and Day 45 (D45) after treatment. Increased RANTES release and mRNA expression were observed in 24-h culture of peripheral blood MNC collected at D4h. This was followed by a decrease in the production of RANTES, IL-8 and MCP-1, 45 days after initiation of RVIT. The same pattern was observed after in vitro venom stimulation of MNC. At the mRNA level, similar profiles were observed except for IL-8 mRNA which inversely increased during RVIT. These results suggest that RVIT is associated with a general decrease in chemokines which may explain, in part, the clinical efficacy of specific immunotherapy. 相似文献
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This paper presents a hierarchical modular neural network for colour classification in graphic arts, capable of distinguishing among very similar colour classes. The network performs analysis in a rough to fine fashion, and is able to achieve a high average classification speed and a low classification error. In the rough stage of the analysis, clusters of highly overlapping colour classes are detected. Discrimination between such colour classes is performed in the next stage by using additional colour information from the surroundings of the pixel being classified. Committees of networks make decisions in the next stage. Outputs of members of the committees are adaptively fused through the BADD defuzzification strategy or the discrete Choquet fuzzy integral. The structure of the network is automatically established during the training process. Experimental investigations show the capability of the network to distinguish among very similar colour classes that can occur in multicoloured printed pictures. The classification accuracy obtained is sufficient for the network to be used for inspecting the quality of multicoloured prints. 相似文献
7.
Semiconductor optical amplifiers (SOAs) are often used in fiber-optic systems in which device gain must be adjusted precisely without disturbing the surrounding system. We have developed an unobtrusive technique for measuring SOA gain based on the peak wavelength of the device's amplified spontaneous emission spectrum. This methodology also expedites gain measurements for systems in which an SOA dynamically switches on and off. We further confirm the reliability and robustness of this methodology 相似文献
8.
Ishay JS Plotkin M Ermakov NY Volynchik S Barkay Z Bergman DJ 《Journal of electron microscopy》2006,55(1):41-49
In the social wasps Vespa orientalis and Paravespula germanica (Hymenoptera, Vespinae), a thermogenic center has been found in the dorsal part of the first thoracic segment. The temperature in this region of the prothorax is higher by 6-9 degrees C than that at the tip of the abdomen, and this in actively flying hornets outside the nest (workers, males or queens) as well as in hornets inside the nest that attend to the brood in the combs. On viewing the region from the outside, one discerns a canal or rather a fissure in the cuticle, which commences at the center of the dorsal surface of the prothorax and extends till the mesothorax. Thus the length of this canal or fissure is approximately 5-7 mm and it is seen to contain numerous thin hairs whose shape varies from that of the hairs alongside the structure. Beneath the cuticle in this region there are dorsoventral as well as longitudinal muscles in abundance, much the same as the musculature in the remaining thoracic segments (i.e. the meso- and metathorax), which activate the two pairs of wings. The canal-bearing segment is of course devoid of wings, and its dorsoventral muscles are attached to the cuticle, which in this region resembles a bowl harboring several layers of epithelium that boasts numerous butterfly-shaped tracheal branches. Additionally there are layers that display lymph-filled spaces and also perforated layers and depressions, and beneath all these is a lace-like layer that also coats the cuticle's hollows. Underneath the cuticle proper, there are numerous large mitochondria and tracheae, which occupy a considerable part of the cuticular epithelium surface. These abundant mitochondria are, most probably, the main element of heat production in the thermogenic center. 相似文献
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Low-power W-band CPWG InAs/AlSb HEMT low-noise amplifier 总被引:1,自引:0,他引:1
Riemer P.J. Buhrow B.R. Hacker J.B. Bergman J. Brar B. Gilbert B.K. Daniel E.S. 《Microwave and Wireless Components Letters, IEEE》2006,16(1):40-42
We present the development of a low-power W-band low-noise amplifier (LNA) designed in a 200-nm InAs/AlSb high electron mobility transistor (HEMT) technology fabricated on a 50-/spl mu/m GaAs substrate. A single-stage coplanar waveguide with ground (CPWG) LNA is described. The LNA exhibits a noise figure of 2.5 dB and an associated gain of 5.6 dB at 90 GHz while consuming 2.0 mW of total dc power. This is, to the best of our knowledge, the lowest reported noise figure for an InAs/AlSb HEMT LNA at 90 GHz. Biased for maximum gain, the single-stage amplifier presents 6.7-dB gain and an output 1-dB gain compression point (P1dB) of -6.7dBm at 90 GHz. The amplifier provides broad-band gain, greater than 5dB over the entire W-band. 相似文献
10.
Bergman J.I. Chang J. Joo Y. Matinpour B. Laskar J. Jokerst N.M. Brooke M.A. Brar B. Beam E. III 《Electron Device Letters, IEEE》1999,20(3):119-122
The combination of resonant tunneling diodes (RTDs) and complementary metal-oxide-semiconductor (CMOS) silicon circuitry can offer substantial improvement in speed, power dissipation, and circuit complexity over CMOS-only circuits. We demonstrate the first integrated resonant tunneling CMOS circuit, a clocked 1-bit comparator with a device count of six, compared with 21 in a comparable all-CMOS design. A hybrid integration process is developed for InP-based RTDs which are transferred and bonded to CMOS chips. The prototype comparator shows sensitivity in excess of 106 VIA, and achieves error-free performance in functionality testing. An optimized integration process, under development, can yield high-speed, low power circuits by lowering the high parasitic capacitance associated with the prototype circuit 相似文献