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排序方式: 共有75条查询结果,搜索用时 15 毫秒
1.
Olga Yu Kurapova Sergey M. Shugurov Evgenia A. Vasil'eva Daniil A. Savelev Vladimir G. Konakov Sergey I. Lopatin 《Ceramics International》2021,47(8):11072-11079
Ceria-based solid solutions are important materials for high- and medium-temperature electrochemical applications. However, the stabilities of both binary and ternary ceria-based solid solutions are insufficient at elevated temperatures, which limits their application as solid electrolytes or SOFC cathodes. Data on the high-temperature stability of ceria-based ceramics are unavailable in the literature. In the present study, we report a thermodynamic stability investigation of Y2O3-CeO2 and Y2O3-ZrO2-CeO2 solid solutions. The thermal prehistories of binary and ternary systems were investigated using STA, XRD, and ESCA techniques. The vaporization processes were investigated in the temperature range of 1577–2227°С via the Knudsen effusion mass spectrometry technique. Using data on the component activity in solid-phase thermodynamic properties of Y2O3-CeO2 solid solutions, which is represented as the Gibbs energy, the excess Gibbs energy was calculated as a function of the ceria mol. %. It was shown that the reduction of Ce4+ to Ce3+ in Y2O3-CeO2 and Y2O3-ZrO2-CeO2 solid solutions corresponds to less-negative Gibbs energy compared to ZrO2-CeO2 solid solutions. 相似文献
2.
Evgenia Adamopoulou Konstantinos Demestichas Panagiotis Demestichas Michael Theologou 《International Journal of Communication Systems》2008,21(3):311-330
Cognitive radio systems dynamically reconfigure the algorithms and parameters they use, in order to adapt to the changing environment conditions. However, reaching proper reconfiguration decisions presupposes a way of knowing, with high enough assurance, the capabilities of the alternate configurations, especially in terms of achievable transmission capacity and coverage. The present paper addresses this problem, firstly, by specifying a complete process for extracting estimations of the capabilities of candidate configurations, in terms of transmission capacity and coverage, and, secondly, by enhancing these estimations with the employment of a machine learning technique. The technique is based on the use of Bayesian Networks, in conjunction with an effective learning and adaptation strategy, and aims at extracting and exploiting knowledge and experience, in order to reach robust (i.e. stable and reliable) estimations of the configurations' capabilities. Comprehensive results of the proposed method are presented, in order to validate its functionality. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
3.
Dmitrii Iudin Marina Vasilieva Elena Knyazeva Viktor Korzhikov-Vlakh Elena Demyanova Antonina Lavrentieva Yury Skorik Evgenia Korzhikova-Vlakh 《International journal of molecular sciences》2022,23(5)
The growing number of drug-resistant pathogenic bacteria poses a global threat to human health. For this reason, the search for ways to enhance the antibacterial activity of existing antibiotics is now an urgent medical task. The aim of this study was to develop novel delivery systems for polymyxins to improve their antimicrobial properties against various infections. For this, hybrid core–shell nanoparticles, consisting of silver core and a poly(glutamic acid) shell capable of polymyxin binding, were developed and carefully investigated. Characterization of the hybrid nanoparticles revealed a hydrodynamic diameter of approximately 100 nm and a negative electrokinetic potential. The nanoparticles demonstrated a lack of cytotoxicity, a low uptake by macrophages, and their own antimicrobial activity. Drug loading and loading efficacy were determined for both polymyxin B and E, and the maximal loaded value with an appropriate size of the delivery systems was 450 µg/mg of nanoparticles. Composite materials based on agarose hydrogel were prepared, containing both the loaded hybrid systems and free antibiotics. The features of polymyxin release from the hybrid nanoparticles and the composite materials were studied, and the mechanisms of release were analyzed using different theoretical models. The antibacterial activity against Pseudomonas aeruginosa was evaluated for both the polymyxin hybrid and the composite delivery systems. All tested samples inhibited bacterial growth. The minimal inhibitory concentrations of the polymyxin B hybrid delivery system demonstrated a synergistic effect when compared with either the antibiotic or the silver nanoparticles alone. 相似文献
4.
Alexey S. Kazakov Alexander D. Sofin Nadezhda V. Avkhacheva Evgenia I. Deryusheva Victoria A. Rastrygina Maria E. Permyakova Vladimir N. Uversky Eugene A. Permyakov Sergei E. Permyakov 《International journal of molecular sciences》2022,23(4)
Interferon-β (IFN-β) is a pleiotropic cytokine secreted in response to various pathological conditions and is clinically used for therapy of multiple sclerosis. Its application for treatment of cancer, infections and pulmonary diseases is limited by incomplete understanding of regulatory mechanisms of its functioning. Recently, we reported that IFN-β activity is affected by interactions with S100A1, S100A4, S100A6, and S100P proteins, which are members of the S100 protein family of multifunctional Ca2+-binding proteins possessing cytokine-like activities (Int J Mol Sci. 2020;21(24):9473). Here we show that IFN-β interacts with one more representative of the S100 protein family, the S100B protein, involved in numerous oncological and neurological diseases. The use of chemical crosslinking, intrinsic fluorescence, and surface plasmon resonance spectroscopy revealed IFN-β binding to Ca2+-loaded dimeric and monomeric forms of the S100B protein. Calcium depletion blocks the S100B–IFN-β interaction. S100B monomerization increases its affinity to IFN-β by 2.7 orders of magnitude (equilibrium dissociation constant of the complex reaches 47 pM). Crystal violet assay demonstrated that combined application of IFN-β and S100B (5–25 nM) eliminates their inhibitory effects on MCF-7 cell viability. Bioinformatics analysis showed that the direct modulation of IFN-β activity by the S100B protein described here could be relevant to progression of multiple oncological and neurological diseases. 相似文献
5.
Evgenia Kollia Xrisoula Saridaki Dimitrios Karagiannis Vassilis Kostopoulos 《应用聚合物科学杂志》2020,137(13):48787
Present work investigates the effect of hydrothermal aging of flax fiber-reinforced bio-based epoxy resin laminates on the mechanical and thermomechanical properties of the composites. Three different types of bio-based resins were used. Plates reinforced with eight layers plain weave flax fibers of 150 g/m2, manufactured using Resin Transfer Molding (RTM), compression molding or autoclave technique depends on type of the resin. One dimensional Fickian behavior shows a good fitting to the experimental data derived from weight measurements. The water uptake at the equilibrium state in the case of 60 °C temperature was slightly greater than that at 40 °C. The mechanical properties after hydrothermal aging show a significant reduction and do not return to their initial values even after the drying process. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48787. 相似文献
6.
Artemis A. Koutsorodi Evgenia F. Adamopoulou Konstantinos P. Demestichas Michael E. Theologou 《Wireless Personal Communications》2007,43(4):1303-1321
This paper presents a middleware platform for managing devices that operate in heterogeneous environments. The proposed management
framework supports terminal-controlled, preference-based access network selection. Two separate problems are identified in
this domain: one involving the computation of optimal allocations of services to access networks and quality levels (service
configuration), and one concerning the dynamic inference of the user’s preferences, according to the usage context (user profiling).
This paper includes an approach to the definition, mathematical formulation and solution of both these problems. Indicative
results of the proposed solution methods are presented in the context of a real-life scenario simulating a day in the life
of an ordinary user. 相似文献
7.
Konstantinos Demestichas Evgenia Adamopoulou Michael Theologou 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2009,13(10):945-958
Beyond 3G (B3G) wireless connectivity can efficiently be realized by exploiting cognitive networking concepts. Cognitive systems
dynamically reconfigure the radio access technologies and the spectrum they use, based on experience, in order to adapt to
the changing environment conditions. However, dynamic reconfiguration decisions call for robust discovery, i.e., radio-scene
analysis and channel identification schemes. This paper intends to contribute in the areas of radio-scene analysis and channel
identification: first, by providing an overview of interference estimation methods, and explaining how capacity estimations
can be derived based on the measured interference levels; second, by specifying the information flow for the radio-scene analysis
process of a cognitive radio system; and third, by enhancing the above with a learning system, which is essential for obtaining
a truly cognitive process. The proposed approach lies in the introduction of a robust probabilistic model for optimal prediction
of the capabilities of alternative configurations, in terms of capacity. 相似文献
8.
Konstantinos P. Demestichas Evgenia F. Adamopoulou John G. Markoulidakis Michael E. Theologou 《Journal of Network and Computer Applications》2009,32(1):116-134
In the current market conditions, network operators are in search of novel value-added services that will increase their revenue. This paper introduces the innovative concept of Anonymous Mobile Community (AMC) services and thoroughly defines and describes a robust platform targeted for their deployment. AMC services take advantage of the terminals’ capabilities to collect information and deliver it to the network. In this context, terminals are enabled to form communities that serve as sources of information. In these communities, the anonymity and privacy of the end-users are respected and guarded. Several examples of promising AMC services are presented and categorized. An indicative example application is the provision of real-time information regarding road-traffic conditions, based on the location and speed of mobile terminals. A system aiming at the provision of diverse AMC services is proposed, and its requirements, architecture and functionality are described in detail. The related scalability issues and business models are carefully outlined, and a use case scenario as well as trial results are presented. 相似文献
9.
Samoli E Kougea E Kassomenos P Analitis A Katsouyanni K 《The Science of the total environment》2011,409(11):2049-2054
Recent reports investigate whether windblown desert dust may exacerbate the short-term health effects associated with particulate pollution in urban centers. We have tested this hypothesis by using daily air pollution and mortality data for Athens, Greece during the period 2001-2006.We investigated the effects of exposure to particulate matter with aerodynamic diameter < 0 μg/m3 (PM10) on total and cause specific mortality, during days with and without windblown desert dust, for all ages, stratified by age groups and by sex. We identified 141 dust days between 2001 and 2006. We used Poisson regression models with penalized splines to control for possible confounding by season, meteorology, day of the week and holiday effect.A 10 μg/m3 increase in PM10 was associated with a 0.71% (95% confidence interval (CI): 0.42% to 0.99%) increase in all deaths. The effects for total and cause specific mortality were greater for those ≥ 75 years of age, while for total mortality higher effects were observed among females. The main effect of desert dust days and its interaction with PM10 concentrations were significant in all cases except for respiratory mortality and cardiovascular mortality among those < 75 years. The negative interaction pointed towards lower particle effects on mortality during dust events.We found evidence of modification of the adverse health effects of PM10 on mortality in Athens, Greece with desert dust events: the particle effects were significantly higher during non-desert dust days. Our analyses indicate that traffic related particles, which prevail on non-desert dust days, have more toxic effects than the ones originating from long-range transport, such as Sahara dust. 相似文献
10.
Ruslan Kashapov Alsu Ibragimova Rais Pavlov Dinar Gabdrakhmanov Nadezda Kashapova Evgenia Burilova Lucia Zakharova Oleg Sinyashin 《International journal of molecular sciences》2021,22(13)
Encapsulation of cargoes in nanocontainers is widely used in different fields to solve the problems of their solubility, homogeneity, stability, protection from unwanted chemical and biological destructive effects, and functional activity improvement. This approach is of special importance in biomedicine, since this makes it possible to reduce the limitations of drug delivery related to the toxicity and side effects of therapeutics, their low bioavailability and biocompatibility. This review highlights current progress in the use of lipid systems to deliver active substances to the human body. Various lipid compositions modified with amphiphilic open-chain and macrocyclic compounds, peptide molecules and alternative target ligands are discussed. Liposome modification also evolves by creating new hybrid structures consisting of organic and inorganic parts. Such nanohybrid platforms include cerasomes, which are considered as alternative nanocarriers allowing to reduce inherent limitations of lipid nanoparticles. Compositions based on mesoporous silica are beginning to acquire no less relevance due to their unique features, such as advanced porous properties, well-proven drug delivery efficiency and their versatility for creating highly efficient nanomaterials. The types of silica nanoparticles, their efficacy in biomedical applications and hybrid inorganic-polymer platforms are the subject of discussion in this review, with current challenges emphasized. 相似文献