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991.
O. L. V. Costa R. P. Marques 《Mathematics of Control, Signals, and Systems (MCSS)》1999,12(2):167-195
Discrete-time coupled algebraic Riccati equations that arise in quadratic optimal control and H
∞-control of Markovian jump linear systems are considered. First, the equations that arise from the quadratic optimal control
problem are studied. The matrix cost is only assumed to be hermitian. Conditions for the existence of the maximal hermitian
solution are derived in terms of the concept of mean square stabilizability and a convex set not being empty. A connection
with convex optimization is established, leading to a numerical algorithm. A necessary and sufficient condition for the existence
of a stabilizing solution (in the mean square sense) is derived. Sufficient conditions in terms of the usual observability
and detectability tests for linear systems are also obtained. Finally, the coupled algebraic Riccati equations that arise
from the H
∞-control of discrete-time Markovian jump linear systems are analyzed. An algorithm for deriving a stabilizing solution, if
it exists, is obtained. These results generalize and unify several previous ones presented in the literature of discrete-time
coupled Riccati equations of Markovian jump linear systems.
Date received: November 14, 1996. Date revised: January 12, 1999. 相似文献
992.
LJ Marques L Zheng N Poulakis J Guzman U Costabel 《Canadian Metallurgical Quarterly》1999,159(2):508-511
Tumor necrosis factor-alpha (TNF-alpha) is an important proinflammatory cytokine. Recently, pentoxifylline (POF) has been shown to suppress the synthesis of TNF-alpha from lipopolysaccharide (LPS)-stimulated human monocytes in cell cultures and in vivo. The aim of this study was to investigate whether POF-induced suppression of TNF-alpha secretion affects peripheral blood monocytes (PBM) and alveolar macrophages (AM) equally, and whether POF is able to suppress the spontaneous TNF-alpha production from AM in pulmonary sarcoidosis in vitro. In seven patients without interstitial lung disease we studied the effect of POF on LPS-stimulated PBM and AM cultured for 24 h. In six patients with sarcoidosis we investigated the effect of POF on the enhanced spontaneous TNF-alpha production by AM in vitro. POF induced a dose-dependent suppression of the LPS-stimulated TNF-alpha production which was not different for PBM and AM, respectively. In sarcoidosis, POF inhibited the spontaneous TNF-alpha production of AM at 0.1 mM by 91% and at 1 mM by 98%. In conclusion, POF inhibits LPS-induced TNF-alpha production from PBM and AM to a similar extent and can also inhibit the exaggerated spontaneous TNF-alpha production from AM in sarcoidosis in vitro. This may be the basis for further clinical trials to evaluate POF as an immunotherapeutic agent in sarcoidosis. 相似文献
993.
Mariana Fronja Carosia Cristiane Marques dos Reis Isabel Kimiko Sakamoto Maria Bernadete Amâncio Varesche Edson Luiz Silva 《International Journal of Hydrogen Energy》2017,42(15):9600-9610
The aim of this study was to evaluate the influence of C/P and C/N ratios on the production of hydrogen and ethanol in four anaerobic fluidized bed reactors: R1 (C/N = 100), R2 (C/N = 150), R3 (C/N = 200), and R4 (C/N = 250). The hydraulic retention time (HRT) was maintained at 2 h, and the C/P ratios varied from 300 to 1100. Reactors were filled with grounded tire and fed with synthetic substrate containing glucose (5000 mg L?1). The effluent pH was around 3.7. The highest values for hydrogen yield (HY) and hydrogen production rate (HPR) were obtained at a C/P = 700 ratio in all reactors. The best performance was achieved at R3 (C/N = 200): HY of 0.76 mol H2 mol?1 glucose and HPR of 0.70 L h?1 L?1. The highest value for ethanol yield was obtained at C/P = 700 in R1 (1.5 mol EtOH mol?1 glucose). Ethanol- and hydrogen-producing fermenters, such as Ethanoligenens sp. and Clostridium sp. were identified by molecular analysis. Lactobacillus sp. was also identified in this study. 相似文献
994.
Francisco Silva Alice DOnofrio Carolina Mendes Catarina Pinto Ana Marques Maria Paula Cabral Campello Maria Cristina Oliveira Paula Raposinho Ana Belchior Salvatore Di Maria Fernanda Marques Carla Cruz Josu Carvalho Antnio Paulo 《International journal of molecular sciences》2022,23(2)
Despite some progress, the overall survival of patients with glioblastoma (GBM) remains extremely poor. In this context, there is a pressing need to develop innovative therapy strategies for GBM, namely those based on nanomedicine approaches. Towards this goal, we have focused on nanoparticles (AuNP-SP and AuNP-SPTyr8) with a small gold core (ca. 4 nm), carrying DOTA chelators and substance P (SP) peptides. These new SP-containing AuNPs were characterized by a variety of analytical techniques, including TEM and DLS measurements and UV-vis and CD spectroscopy, which proved their high in vitro stability and poor tendency to interact with plasma proteins. Their labeling with diagnostic and therapeutic radionuclides was efficiently performed by DOTA complexation with the trivalent radiometals 67Ga and 177Lu or by electrophilic radioiodination with 125I of the tyrosyl residue in AuNP-SPTyr8. Cellular studies of the resulting radiolabeled AuNPs in NKR1-positive GBM cells (U87, T98G and U373) have shown that the presence of the SP peptides has a crucial and positive impact on their internalization by the tumor cells. Consistently, 177Lu-AuNP-SPTyr8 showed more pronounced radiobiological effects in U373 cells when compared with the non-targeted congener 177Lu-AuNP-TDOTA, as assessed by cell viability and clonogenic assays and corroborated by Monte Carlo microdosimetry simulations. 相似文献
995.
996.
Gimerson Weigert Subtil Jean César Marinozi Vicentini Daiane Marques de Oliveira Lidiane Vizioli de Castro-Hoshino Patricia Hissae Yassue-Cordeiro Renata Corrêa Vicentino Mara Heloisa Neves Olsen Scaliante 《加拿大化工杂志》2023,101(3):1345-1357
The photocatalyst composition affects the chemical–physical properties and directly impacts photocatalytic activity, both in the hydrogen production and degradation of organic contaminants. In this work, the influence of zeolitic structures NaA, NaY, and ZSM-5 combined with a 10% active phase, TiO2 catalyst doped with 1% copper, and cobalt cocatalysts was tested to mineralize the reactive blue dye (CI250) and to produce hydrogen by photocatalysis under ultraviolet radiation. The band gap energy was affected mainly by the cocatalyst, while the Brunauer-Emmett-Teller method (BET) area was affected by the zeolite structure as well as the X-ray diffraction (XRD). The most active catalyst was the Cu@TiO2/NaY, which promoted a hydrogen production rate of 240 μmolH2gcat−1 using 10% ethanol (v/v) aqueous solution as a sacrificial agent and mineralization of 53% of the organic dye, followed by the catalysts impregnated on ZSM-5 zeolites, which had discolouration up to 50% and hydrogen evolution of 92.6 and 109.7 μmolH2gcat−1 for the catalyst doped with Cu and Co, respectively. 相似文献
997.
George N. Kotsonis Saeed S. I. Almishal Francisco Marques dos Santos Vieira Vincent H. Crespi Ismaila Dabo Christina M. Rost Jon-Paul Maria 《Journal of the American Ceramic Society》2023,106(10):5587-5611
High-entropy materials defy historical materials design paradigms by leveraging chemical disorder to kinetically stabilize novel crystalline solid solutions comprised of many end-members. Formulational diversity results in local crystal structures that are seldom found in conventional materials and can strongly influence macroscopic physical properties. Thermodynamically prescribed chemical flexibility provides a means to tune such properties. Additionally, kinetic metastability results in many possible atomic arrangements, including both solid-solution configurations and heterogeneous phase assemblies, depending on synthesis conditions. Local disorder induced by metastability, and extensive cation solubilities allowed by thermodynamics combine to give many high-entropy oxide systems utility as electrochemical, magnetic, thermal, dielectric, and optical materials. Though high-entropy materials research is maturing rapidly, much remains to be understood and many compositions still await discovery, exploration, and implementation. 相似文献
998.
999.
1000.
dos Santos Sarah Marcilene Machado de Mello Prado Renato Teixeira Gelza Carliane Marques de Souza Júnior Jonas Pereira de Medeiros Robson Luis Silva Barreto Rafael Ferreira 《SILICON》2022,14(3):773-782
Silicon - The aim of this study was to determine whether silicon (Si) supplied via nutrient solution or foliar spray is nutritionally and physiologically efficient in mitigating potassium (K)... 相似文献