排序方式: 共有33条查询结果,搜索用时 15 毫秒
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J Adnane FA Bizouarn Y Qian AD Hamilton SM Sebti 《Canadian Metallurgical Quarterly》1998,18(12):6962-6970
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The mechanism by which lovastatin lowers cholesterol levels is well characterized but little is known about its anti-mitogenic and anti-tumorigenic mechanism. Here we demonstrate that lovastatin disrupts early events in the mitogenic signaling pathways of insulin. Insulin treatment (200 mM) of quiescent HIR rat-1 fibroblasts results in an 8-fold stimulation of phosphatidylinositol-3-kinase (PI-3-K) activity. Overnight pretreatment of cells with lovastatin (20 microM) inhibits insulin stimulation of PI-3-K activity by 75%. Immunoprecipitation and immunoblotting experiments using antibodies against the regulatory subunit of PI-3-K (p85), phosphotyrosine, and insulin receptor alpha and beta subunits demonstrate that lovastatin inhibits the association of p85 with tyrosine phosphorylated insulin receptor substrate-1 and the beta subunit of the insulin receptor. Furthermore, lovastatin dramatically reduces (70-100%) the level of tyrosine phosphorylated insulin receptor beta subunit following insulin stimulation. These results clearly demonstrate that lovastatin disrupts early events of insulin mitogenic signaling by reducing the levels of tyrosine phosphorylated beta subunit and suggest that this disruption is a potential mechanism for the anti-mitogenic effect of lovastatin. 相似文献
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W. Guiga Y. Swesi S. Galland E. Peyrol P. Degraeve I. Sebti 《Innovative Food Science and Emerging Technologies》2010,11(2):352-360
In this study, ethylcellulose/hydroxypropylmethylcellulose/ethylcellulose (EC/HPMC/EC) three-layer films including Nisaplin® or nisin and lecithins were formulated. Lecithins were used as plasticizers to ensure cohesion between hydrophobic ethylcellulose and hydrophilic HPMC layers. It was observed that the introduction of pure nisin or its non-pure commercial form Nisaplin® into films didn't significantly alter their mechanical and optical properties. Additionally, these nisin or Nisaplin-loaded multilayer films showed significant antimicrobial activity. The comparison of inhibition diameters obtained with EC/HPMC film used as control and EC/HPMC/EC films demonstrated that the three-layer films delayed nisin desorption. This was confirmed by the kinetics of nisin release in a (0.8% w/v) NaCl solution at 28 °C: nisin from two-layer EC/HPMC films totally desorbed within 0.5 h, while the three-layer films allowed to expand nisin release time over 20 h. The ratio of nisin desorption coefficients (kd): kd (EC/HPMC)/kd (EC/HPMC/EC) was determined after desorption modelling, and was found to be up to 118, proving that multilayer films with hydrophobic layers could be a potential way to control nisin release from antimicrobial bio-packagings.Industrial relevanceThis paper concerns active packaging, considered as a new approach to preserve food shelf life. Active packaging is a real gain for plastic and food industrials. Coating was used to obtain antimicrobial packaging. The impact of incorporating the antimicrobial agent in multilayer films on the release kinetics is investigated. 相似文献
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Multimedia Tools and Applications - Orientation of human body is an important feature that can be used for behavioral analysis in surveillance systems. This cue contains useful information such as... 相似文献
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This paper presents a new method combining sliding mode control (SMC) and fuzzy logic control (FLC) to enhance the robustness and performance for a class of non-linear control systems. This fuzzy sliding mode control (FSMC) is developed for application in the area for controlling the speed and flux loops of asynchronous motors. The proposed control law can solve those problems associated with the conventional control by sliding mode control, such as high current, flux and torque chattering, variable switching frequency and variation of parameters, in which a robust fuzzy logic controller replaces the discontinuous part of the classical sliding mode control law. Simulation results of the proposed FSMC technique on the speed and flux rotor controllers present good dynamic and steady-state performances compared to the classical SMC in terms of reduction of the torque chattering, quick dynamic torque response and robustness to disturbance and variation of parameters. 相似文献
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Craig Schlenoff Anthony Pietromartire Zeid Kootbally Stephen Balakirsky Sebti Foufou 《Robotics and Autonomous Systems》2013,61(11):1224-1234
In this paper, we describe a novel approach for representing state information for the purpose of intention recognition in cooperative human–robot environments. States are represented by a combination of spatial relationships in a Cartesian frame along with cardinal direction information. This approach is applied to a manufacturing kitting operation, where humans and robots are working together to develop kits. Based upon a set of predefined high-level state relationships that must be true for future actions to occur, a robot can use the detailed state information described in this paper to infer the probability of subsequent actions occurring. This would allow the robot to better help the human with the task or, at a minimum, better stay out of his or her way. 相似文献
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Samir Chouali Hassan Mountassir Sebti Mouelhi 《Electronic Notes in Theoretical Computer Science》2010,238(6):3-13
An interesting formal approach to specify component interfaces is interface automata based approach, which is proposed by L. Alfaro and T. Henzinger. These formalisms have the ability to model both the input and output requirements of components system. In this paper, we propose a method to enrich interface automata by the semantics of actions in order to verify components interoperability at the levels of signatures, semantics, and protocol interactions of actions. These interfaces consist of a set of required and offered actions specified by Pre and Post conditions. The verification of the compatibility between interface automata reuse the L. Alfaro and T. Henzinger proposed algorithm and adapt it by taking into account the action semantics. Our approach is illustrated by a case study of the vehicle CyCab. 相似文献
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Urban drainage networks are subjected to increased runoff caused by urbanization and climate change. Wear and tear, coupled with a lack of network maintenance, reduces the hydraulic capacity of these networks and results in surcharged flows, discharges and overflows calling for the need to institute effective restructuring strategies. The purpose of this study was to develop an optimization model for the optimal selection and placement of structural best management practices (BMPs). In this research, four types of structural BMPs were being considered (i.e., retention pond, green roofs, infiltration trenches and vegetated depressions). The objective function was to minimize the total cost of BMPs, within the constraints of (1) draining infrequent heavy rainfall without surcharging the conduits and (2) driving frequent small rainfall into the water-treatment plant without overflows. The model was tested on a case study in the Greater Montreal Area and the results obtained from the model effectively demonstrated its capacity to improve the hydraulic and environmental performances by adopting optimal BMPs placement strategies. 相似文献