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排序方式: 共有621条查询结果,搜索用时 31 毫秒
1.
Automation and Remote Control - We consider multicriteria minimax optimization problems with criteria in the form of the maxima of functionals given by the induced norms of linear operators taking... 相似文献
2.
D Brown S Kogan E Lagasse I Weissman M Alcalay PG Pelicci S Atwater JM Bishop 《Canadian Metallurgical Quarterly》1997,94(6):2551-2556
The malignant cells of acute promyelocytic leukemia (APL) contain a reciprocal chromosomal translocation that fuses the promyelocytic leukemia gene (PML) with the retinoic acid receptor alpha gene (RAR alpha). To test the hypothesis that the chimera PMLRAR alpha plays a role in leukemogenesis, we expressed a PMLRAR alpha cDNA in myeloid cells of transgenic mice. PMLRAR alpha transgenic mice exhibited impaired neutrophil maturation early in life, which progressed at a low frequency over the course of several months to overt APL. Both the preleukemic state and the leukemia could be transplanted to nontransgenic mice, and the transplanted preleukemia could progress to APL. The APL recapitulated features of the human disease, including a response to retinoic acid. Retinoic acid caused the leukemic cells to differentiate in vitro and in vivo, eliciting remissions of both the preleukemic state and APL in mice. Our results demonstrate that PMLRAR alpha impairs neutrophil differentiation and initiates the development of APL. The transgenic mice described here provide an apparently accurate model for human APL that includes clear evidence of tumor progression. The model should be useful for exploring the molecular pathogenesis of APL and the mechanisms of the therapeutic response to retinoic acid, as well as for preclinical studies of therapeutic regimens. 相似文献
3.
This article presents and evaluates the performance of a location sensing algorithm developed and demonstrated at Carnegie Mellon University. We compare our model with various others based on different architectures and software paradigms. We show comparative results in accuracy, the complexity of training, total power consumption, and suitability to users. Our method reduces training complexity by a factor of eight over previous algorithms, and yields noticeably better accuracy. The algorithm uses less power than previous models, and offers a more secure privacy model. 相似文献
4.
Necessary and sufficient conditions for robust stability of a family of polynomials with complex coefficients are provided. This work generalizes a frequency-domain criteria for robust stability of continuous linear systems reported on by Y.Z. Tsypkin and B.T. Polyak (1991) 相似文献
5.
An optimal control approach to continuous-time aggregate production planning problems is presented. The proposed approach describes the production and capacity evolution (expansion, sell and deterioration) processes in the form of differential equations with regular production, subcontracting and capacity change rates controllable on one hierarchical level. In this way, the traditional disadvantages of the two-level problem consideration (one level for strategic capacity planning and the other for production smoothing) are avoided. Analytical properties for optimal production and capacity control regimes and conditions for their changeover are derived by the maximum principle. Based on these results, an insight into the optimal behaviour of the production system is gained and a fast numerical method is developed to identify and sequence the optimal regimes for arbitrary demand profiles. A computational example illustrates the effectiveness of the approach. 相似文献
6.
7.
Journal of Mathematical Imaging and Vision - A correction to this paper has been published: https://doi.org/10.1007/s10851-021-01028-0 相似文献
8.
Yu. M. Lakhtin Ya. D. Kogan D. P. Shashkov L. G. Petrova 《Metal Science and Heat Treatment》1989,31(6):417-421
1. | During nitriding of nickel alloys which contain Ti in the temperature interval from 1000–1200°C for 5–15 h, the conditions are created for the formation of only internal nitriding and the formation of a nitride zone does not occur. These are prerequisites for increased heat resistance. |
2. | In nickel alloys containing a higher concentration of chromium, a zone of internal nitriding of large thickness occurs during the nitriding process. At the most intense levels of nitriding (t=1200°C and =15h) a through saturation of a 1.5-mm-thick sample of high chrome alloy 2 occurs. |
3. | As a result of nitriding nickel alloys which contain additions of titanium, there is an increase in strength due to the formation of dispersed particles of titanium nitride within the matrix. These particles inhibit the high temperature plastic flow. Another factor which increases the heat resistance of these alloys is the solubility of nitrogen in the matrix which increases the recrystallization temperature, and consequently, the high temperature strength. |
4. | In the alloy which contained the greater concentration of Cr, there is a more intense growth of the diffusion layer. On the other hand, the high concentration of Cr, the lower concentration of Ti, and the absence of Co are the reasons there is a lower increase in the heat resistance as a result of nitriding. |
9.
Anna A. Pendina Mikhail I. Krapivin Olga A. Efimova Andrei V. Tikhonov Irina D. Mekina Evgeniia M. Komarova Alla S. Koltsova Alexander M. Gzgzyan Igor Yu. Kogan Olga G. Chiryaeva Vladislav S. Baranov 《International journal of molecular sciences》2021,22(11)
The human lifespan is strongly influenced by telomere length (TL) which is defined in a zygote—when two highly specialised haploid cells form a new diploid organism. Although TL is a variable parameter, it fluctuates in a limited range. We aimed to establish the determining factors of TL in chromosomes of maternal and paternal origin in human triploid zygotes. Using Q-FISH, we examined TL in the metaphase chromosomes of 28 human triploid zygotes obtained from 22 couples. The chromosomes’ parental origin was identified immunocytochemically through weak DNA methylation and strong hydroxymethylation in the sperm-derived (paternal) chromosomes versus strong DNA methylation and weak hydroxymethylation in the oocyte-derived (maternal) ones. In 24 zygotes, one maternal and two paternal chromosome sets were identified, while the four remaining zygotes contained one paternal and two maternal sets. For each zygote, we compared mean relative TLs between parental chromosomes, identifying a significant difference in favour of the paternal chromosomes, which attests to a certain “imprinting” of these regions. Mean relative TLs in paternal or maternal chromosomes did not correlate with the respective parent’s age. Similarly, no correlation was observed between the mean relative TL and sperm quality parameters: concentration, progressive motility and normal morphology. Based on the comparison of TLs in chromosomes inherited from a single individual’s gametes with those in chromosomes inherited from different individuals’ gametes, we compared intraindividual (intercellular) and interindividual variability, obtaining significance in favour of the latter and thus validating the role of heredity in determining TL in zygotes. A comparison of the interchromatid TL differences across the chromosomes from sets of different parental origin with those from PHA-stimulated lymphocytes showed an absence of a significant difference between the maternal and paternal sets but a significant excess over the lymphocytes. Therefore, interchromatid TL differences are more pronounced in zygotes than in lymphocytes. To summarise, TL in human zygotes is determined both by heredity and parental origin; the input of other factors is possible within the individual’s reaction norm. 相似文献
10.
Piryatinskii B. M. Sobolev B. A. Serebrinskii L. E. Kogan A. I. Deineko P. S. Obaturov I. V. 《Chemistry and Technology of Fuels and Oils》1970,6(7):488-491
Chemistry and Technology of Fuels and Oils - 相似文献