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211.
Z Ma S Ramanadham K Kempe Z Hu J Ladenson J Turk 《Canadian Metallurgical Quarterly》1996,1308(2):151-163
We prepared polymers having a phospholipid polar group, poly [omega-methacryloyloxyalkyl phosphorylcholine (MAPC)-co-n-butyl methacrylate(BMA)], as new biomedical materials and evaluated their blood compatibility with attention to protein adsorption and platelet adhesion. The total amount of proteins adsorbed on the polymer surface from human plasma was determined, and the distribution of adsorbed proteins on the plasma-contacting surface was analyzed. The amount of proteins adsorbed on every poly (MAPC-co-BMA) was small compared with that observed on polymers without the phospholipid polar group. However, there was no significant difference in the amount of adsorbed proteins on the poly(MAPC-co-BMA) even when the methylene chain length between the phospholipid polar group and the backbone in the MAPC moiety was altered. Platelet adhesion on the polymer surface from a platelet suspension in a buffered solution was evaluated with and without plasma treatment on the surface. When a rabbit platelet suspension was brought into contact with the poly(BMA) surface after treatment with plasma, many platelets adhered and aggregated. However, a reduced amount of platelet adhered on the poly(BMA) was found in the case of direct contact with the platelet suspension. On the other hand, the poly(MAPC-co-BMA)s could inhibit platelet adhesion under both conditions. Based on these results, it can be concluded that the proteins adsorbed on the surface play an important role in determining the platelet adhesion and suppression of the protein adsorption on the surface, which is one of the most significant ways of inhibiting platelet adhesion. 相似文献
212.
气—液式热管换热器在硫酸工业中的应用研究 总被引:4,自引:0,他引:4
本文研制的气-液式热管换热器应用于硫酸生产中SO3气体的余热回收。它具有传热性能好、流动阻力小、寿命长、体积小、节能效果显著和易清垢等优点。 相似文献
213.
Q Hu M Trevisan Y Xu W Dong SA Berger SD Lyman MD Minden 《Canadian Metallurgical Quarterly》1995,95(6):2530-2538
The growth of human leukemic cells in culture and in vivo is dependent upon the presence of hematopoietic growth factors. Most populations of human leukemic acute myeloblastic leukemia (AML) cells express c-Kit on their surface and respond to Kit ligand (KL) in culture. To determine if this interaction was of potential significance in vivo we used a mouse model system. 32D cells, a murine IL-3-dependent myeloid cell line, were rendered KL responsive by transfection of the murine c-Kit. After injection of 32D or 32D-Kit cells into syngeneic hosts, animals bearing 32D-Kit cells, but not 32D cells, became moribund and were killed. These animals had circulating leukemic blast cells, infiltration of bone marrow, spleen, brain, liver, lung, and kidney. Cells recovered from some of the animals continued to be dependent upon IL-3 or KL for growth while in other cases the cells were factor independent. This model illustrates that the constitutive expression of c-Kit enhances the leukemic potential of 32D cells. The model will be useful for studying the progression of leukemia in vivo and testing whether interruption of the interaction of Kit and KL can affect the growth of leukemic cells. 相似文献
214.
变结构变参数设计方法及其在机械CAD中的应用 总被引:4,自引:0,他引:4
提出了一种新颖的机械结构设计思想-变结构变参数设计方法,并结合实例,阐述了变结构变参数设计的概念、原则、实施措施和意义。由此对I-deas软件包进行了二次开发,编制了发动机曲轴专用CAD软件程序,并用某型号发动机曲轴进行了验证。 相似文献
215.
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217.
Sha Lu Yong Hu O'Hara M. Bogy D.B. Singh Bhatia C. Yiao-Tee Hsia 《IEEE transactions on magnetics》1996,32(1):103-109
Three sub-25 nm fly height sliders are presented for near contact recording. The designs are geared towards the goal of achieving 10 Gb/in 2 areal density. The optimization procedure presented shows promise for facilitating achievement of this goal. The dynamic simulations show the stability of these designs when disturbed from their steady state conditions 相似文献
218.
Leo Egghe 《Scientometrics》2005,63(2):277-296
Summary We study new and existing data sets which show that growth rates of sources usually are different from growth rates of items. Examples: references in publications grow with a rate that is different (usually higher) from the growth rate of the publications themselves; article growth rates are different from journal growth rates and so on. In this paper we interpret this phenomenon of “disproportionate growth' in terms of Naranan's growth model and in terms of the self-similar fractal dimension of such an information system, which follows from Naranan's growth model. The main part of the paper is devoted to explain disproportionate growth. We show that the “simple' 2-dimensional informetrics models of source-item relations are not able to explain this but we also show that linear 3-dimensional informetrics (i.e. adding a new source set) is capable to model disproportionate growth. Formulae of such different growth rates are presented using Lotkaian informetrics and new and existing data sets are presented and interpreted in terms of the used linear 3-dimensional model. 相似文献
219.
In connection with the specific features of high velocity aerated flow generated by hydraulic engineering structures, the mathematical model is developed for high turbulence air-water two-phase flow with the use of twin flow theoretical model in this paper. Furthermore the numerical method is proposed to treat bubbled flows. In addition, on the basis of air-water stratified twin flow model, the new calculation methods and free surface tracking technique are proposed to describe complicated movements of the free surface. Finally, the proposed model is used to calculate artificial aerated flows. The computed results coincide quite well with experimental results. This means that the proposed method can provide solid basis for practical engineering design. 相似文献
220.
Although the dams produce remarkable social and economic benefits, the threat made by unsafe dams to the life and property of people who live in the lower river area is un-negligible. Based on the monitoring data which reflect the safety condition of dams, the risk degree concept is proposed and the analysis system and model for evaluating risk degree (rate) are established in this paper by combining the reliability theory and field monitoring data. The analysis method for risk degree is presented based on Bayesian approach. A five-grade risk degree system for dam operation risk and corresponding risk degree is put forward according to the safety condition of dams. The operation risks of four cascade dams on some river are analyzed by the model and approach presented here and the result is adopted by the owner. 相似文献