首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   10篇
  免费   0篇
化学工业   1篇
无线电   1篇
一般工业技术   4篇
冶金工业   2篇
自动化技术   2篇
  2021年   1篇
  2020年   1篇
  2016年   1篇
  2000年   2篇
  1999年   1篇
  1998年   3篇
  1996年   1篇
排序方式: 共有10条查询结果,搜索用时 15 毫秒
1
1.
A small‐cell network (SCN) constructed by splitting a macro‐cell into numerous small cells using an active antenna array system is studied. A synchronization signal appropriate for the SCN, virtually generated by an eNodeB with 3D beamforming, is proposed for efficient handover in SCNs. The virtual cell synchronization signal (VCSS) carries a macro‐cell ID (MCID) and virtual‐cell ID (VCID) in a hierarchical manner, allowing us to distinguish between an intra‐cell handover (virtual cell handover within a cell without changing the serving eNodeB) and inter‐cell handover (virtual cell handovers across cells while changing the serving eNodeB) in SCNs. Using the signal metrics obtained by the VCSS, an efficient handover measurement technique is proposed which can significantly reduce the processing time and overhead by distinguishing between the intra‐cell/inter‐cell handovers. The performance of the proposed technique is evaluated by simulating two different deployment scenarios of LTE‐based SCN with 3D beamforming. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   
2.
Comprehensive scientific data provide evidence that isolated phytochemicals or whole plant foods may beneficially modify carcinogenesis. The aim of this study was to evaluate the oncostatic activities of Rhus coriaria L. (sumac) using animal models (rat and mouse), and cell lines of breast carcinoma. R. coriaria (as a powder) was administered through the diet at two concentrations (low dose: 0.1% (w/w) and high dose: 1 % (w/w)) for the duration of the experiment in a syngeneic 4T1 mouse and chemically-induced rat mammary carcinoma models. After autopsy, histopathological and molecular analyses of tumor samples in rodents were performed. Moreover, in vitro analyses using MCF-7 and MDA-MB-231 cells were conducted. The dominant metabolites present in tested R. coriaria methanolic extract were glycosides of gallic acid (possible gallotannins). In the mouse model, R. coriaria at a higher dose (1%) significantly decreased tumor volume by 27% when compared to controls. In addition, treated tumors showed significant dose-dependent decrease in mitotic activity index by 36.5% and 51% in comparison with the control group. In the chemoprevention study using rats, R. coriaria at a higher dose significantly reduced the tumor incidence by 20% and in lower dose non-significantly reduced tumor frequency by 29% when compared to controls. Evaluations of the mechanism of oncostatic action using valid clinical markers demonstrated several positive alterations in rat tumor cells after the treatment with R. coriaria. In this regard, histopathological analysis of treated tumor specimens showed robust dose-dependent decrease in the ratio of high-/low-grade carcinomas by 66% and 73% compared to controls. In treated rat carcinomas, we found significant caspase-3, Bax, and Bax/Bcl-2 expression increases; on the other side, a significant down-regulation of Bcl-2, Ki67, CD24, ALDH1, and EpCam expressions and MDA levels. When compared to control specimens, evaluation of epigenetic alterations in rat tumor cells in vivo showed significant dose-dependent decrease in lysine methylation status of H3K4m3 and H3K9m3 and dose-dependent increase in lysine acetylation in H4K16ac levels (H4K20m3 was not changed) in treated groups. However, only in lower dose of sumac were significant decreases in the expression of oncogenic miR210 and increase of tumor-suppressive miR145 (miR21, miR22, and miR155 were not changed) observed. Finally, only in lower sumac dose, significant decreases in methylation status of three out of five gene promoters–ATM, PTEN, and TIMP3 (PITX2 and RASSF1 promoters were not changed). In vitro evaluations using methanolic extract of R. coriaria showed significant anticancer efficacy in MCF-7 and MDA-MB-231 cells (using Resazurin, cell cycle, annexin V/PI, caspase-3/7, Bcl-2, PARP, and mitochondrial membrane potential analyses). In conclusion, sumac demonstrated significant oncostatic activities in rodent models of breast carcinoma that were validated by mechanistic studies in vivo and in vitro.  相似文献   
3.
Amine oxidase (AO, EC. 1.4.3.6) was previously shown to be a very efficient biological recognition element of amperometric biosensors for monitoring biogenic amines. The enzyme was effectively working in both mono- and bienzyme electrode designs, based on either a direct or a mediated electron-transfer pathway. This work focuses on the elucidation of the electron-transfer mechanism of the monoenzymatic unmediated AO-modified biosensor. The observed unmediated catalytic currents were assumed to be caused by (i) a direct electron-transfer process, (ii) the electrooxidation of the formed product, or (iii) their combination. Experiments supporting these assumptions are discussed in detail.  相似文献   
4.
This work presents the design and optimization of amperometric biosensors for the determination of biogenic amines (e.g., histamine, putrescine, cadaverine, tyramine, cystamine, agmatine, spermidine), commonly present in food products, and their application for monitoring of freshness in fish samples. The biosensors were used as the working electrodes of a three-electrode electrochemical cell of wall-jet type, operated at -50 mV vs Ag/AgCl, in a flow injection system. Two different bienzyme electrode designs were considered, one based on the two enzymes [a newly isolated and purified amine oxidase (AO) and horseradish peroxidase (HRP)] simply adsorbed onto graphite electrodes, and one when they were cross-linked to an Os-based redox polymer. The redox hydrogel-based biosensors showed better biosensors characteristics, i.e., sensitivity of 0.194 A M-1 cm-2 for putrescine and 0.073 A M-1 cm-2 for histamine, and detection limits (calculated as three times the signal-to-noise ratio) of 0.17 microM for putrescine and 0.33 microM for histamine. The optimized redox hydrogel-based biosensors were evaluated in terms of stability and selectivity, and were used for the determination of total amine content in fish samples kept for 10 days in different conditions.  相似文献   
5.
A case of phaeohyphomycosis caused by strains of both Alternaria spp. and Phaeosclera dematioides is presented. The biopsy material was studied using histological, immunohistochemical and transmission electron microscopy techniques. The agent's dematiaceous mycelia are composed of thick-walled hyphae, branched and unbranched, with terminal vesicular formations. All the described structures occur alone or in chains within multinuclear giant foreign body-type cells or invading an abscess. Also present are budding forms. Immunostaining of histiocytic inflammatory cells in either. diffuse or granulomatous infiltrates revealed cytoplasmic positivity for lysozyme and Ki-MIP antibody. The lymphocytic infiltrates of the upper corium show predominantly small T lymphocytes (CD3 and CD45RO positive) and absence of CD20-positive B cells. Plasma cells occurring within the infiltrates of the deeper parts show polyclonal expression of both Ig light chains.  相似文献   
6.
The impact of moist-heat sterilization (autoclaving) on the chemical stability of parenteral solutions was examined using two heat-labile products, clindamycin phosphate and succinylcholine chloride injections, as examples. A nonisothermal kinetic model was used to predict the extent of product degradation during autoclaving. The predicted results were found to be in close agreement with the experimental data. For the same peak temperature, a greater loss of product was shown by using a cycle with a higher F0. On the other hand, a higher peak-temperature cycle resulted in less product degradation for the same F0 value. The benefit of a high-temperature cycle was further illustrated by the fact that less chemical degradation for both products was produced by a 122 degrees C cycle with an F0 of 11 as compared to that which occurred during a 116.5 degrees C cycle with an F0 of 8. Although clindamycin phosphate was found to be highly unstable during a conventional autoclaving process, predicted data indicate that a UHT (Ultra-High Temperature) process may be used to sterilize this product with acceptable degradation.  相似文献   
7.
19-Nor-1 alpha, 25-dihydroxyvitamin D2, an analog of vitamin D2, is a nonpolar compound with limited solubility in water. An injectable solution was formulated using a cosolvent system consisting of water, ethanol, and propylene glycol. A statistical response surface approach was used to evaluate the effect of these three solvents on the solubility of the drug (25 degrees C) in the ternary cosolvent system. The data generated from five selected formulations were used to develop a multiple linear regression model that quantitatively defines the solubility of the drug as a function of the cosolvent composition. Close agreement was found between the experimental data and data calculated using the model. The capability of this model to predict drug solubility in cosolvent systems with various combinations of the three solvents was also verified.  相似文献   
8.
Abstract

In the following article, a proprietary method of anonymisation of identifiable statistical data using context-free probabilistic grammar is proposed. The advantage of this method is that it is simple and thanks to this, the identifier is easy to retrieve after masking the identifiable data, e.g. when it is necessary to modify or update the micro-data. This can be done using public-key cryptography, i.e. encrypting some probabilistic context-free grammar with this method. In the case of public statistics, there is often a need to use an anonymised source value, for example when economic operators’ reports are verified by statistical officers. With appropriate information generated by context-free grammar, the verifier can easily identify an economic operator or a natural person. The idea of the anonymising algorithm used in the proposed method is presented by means of an example. According to the authors, the combination of the proposed method with asymmetric encryption of the definition of context-free grammar using public key infrastructure, makes it probable that its resistance to attacks will be quite high. This is because statistical methods that are used in the analysis of natural languages are not susceptible to attacks.  相似文献   
9.
A case of multiple, cutaneous metastases as the first sign of lung cancer in a patient with well-differentiated, papillary, transitional cell carcinoma of the urinary bladder is presented. In the left clavicular region were two, sharply demarcated, dark red tumors measuring 3 and 2 cm in diameter with a history of rapid growth and intermittent spontaneous bleeding. Thorough examination of the patient revealed 16 additional skin lesions, which were dark red macules and papules, 2-3 mm in diameter, situated on the left side of the chest. The skin biopsy material (tumors, macular and papular lesions) was studied using histological and immunohistochemical techniques and showed intact epidermis and massive dermal and subcutaneous metastatic involvement by a small cell carcinoma with neuroendocrine differentiation most likely originating in the lung.  相似文献   
10.
The theoretical development of a trajectory-tracking neural network controller based on the theory of continuous sliding-mode controllers is shown in the paper. Derived equations of the on-line adaptive neural network controller were verified on a real industrial direct-drive 3 degrees of freedom (D.O.F.) PUMA mechanism. The new neural network continuous sliding-mode controller was successfully tested for trajectory-tracking control tasks with respect to three criteria: convergence properties of the proposed control algorithm (high-speed cyclic movement, low-speed movement, high-speed PTP movement), adaptation capability of the algorithm to sudden changes in the manipulator dynamics (load), and generalization properties of the proposed control scheme. An interesting effect of the lower position error after a transient time at sudden load changes is shown.  相似文献   
1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号