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Inflammation is the clinical expression of chemical mediators such as the pro-inflammatory cytokine tumor necrosis factor (TNF-)-alpha produced by macrophages and other cells activated in the immune response. Hence, agents that can inhibit TNF-alpha may be useful in treating arthritis and other diseases resulting from uncontrolled inflammation. We now report that the cleavage of heparin by the enzyme heparinase I generates sulfated disaccharide (DS) molecules that can inhibit the production of TNF-alpha. Administration of nanogram amounts of the sulfated DS molecules to experimental animals inhibited delayed-type hypersensitivity to a skin sensitizer and arrested the joint swelling of immunologically induced adjuvant arthritis. Notably, the sulfated DS molecules showed a bell-shaped dose-response curve in vitro and in vivo: decreased effects were seen using amounts of the DS molecules higher than optimal. Thus, molecular regulators of inflammation can be released from the natural molecule heparin by the action of an enzyme. 相似文献
3.
Ahmed Amine Rekik Florence Azaïs Norbert Dumas Frédérick Mailly Pascal Nouet 《Journal of Electronic Testing》2011,27(3):411-423
This paper presents a behavioral model that can be used to improve the manufacturability of systems based on MEMS convective
sensors. This model permits to handle faults related to process scattering, taking into account not only the electrical and
lateral geometrical parameters but also the influence of the cavity depth. Moreover correlations between conductive and convective
phenomena are included. The model is validated with respect to FEM simulations and a very good agreement is obtained between
the behavioral model and FEM results. The proposed model can then be used in system-level simulations, for instance to evaluate
the impact of process scattering on the performances of the sensing part and/or to investigate different design and calibration
strategies with respect to the system robustness. 相似文献
4.
This paper analyzes a Newsvendor type inventory model in which a manufacturer sells a single product to a retailer store whose
inventory is subject to errors stemming from execution problems. Hence, within the store, all of the products are not available
on shelf for sales either because the replenishment of the shelf from the backroom is subject to execution errors that mainly
result in products lost in the backroom or products misplaced on the other shelves of the store. We compare two situations:
in the first situation, the two supply chain actors are aware of errors and optimize their ordering decisions by taking into
account this issue. The second situation deals with the case where an advanced automatic identification system such as the
Radio Frequency Identification technology is deployed in order to eliminate errors. Each situation is developed for three
scenarios: in the centralized scenario, we consider a single decision-maker who is concerned with maximizing the entire supply
chain’s profit; in the decentralized uncoordinated scenario, the retailer and the manufacturer act as different parties and
do not cooperate. The third scenario is the decentralized coordinated scenario where we give conditions for coordinating the
channel by designing a buyback contract.
The authors would like to thank the editor, Prof. Dr. Hans-Otto Guenther, and two anonymous referees for their constructive
comments to improve this article. 相似文献
5.
Genetic parameters of milk, fat, and protein yields were estimated in the first 3 lactations for registered Tunisian Holsteins. Data included 140,187; 97,404; and 62,221 test-day production records collected on 22,538; 15,257; and 9,722 first-, second-, and third-parity cows, respectively. Records were of cows calving from 1992 to 2004 in 96 herds. (Co)variance components were estimated by Bayesian methods and a 3-trait-3-lactation random regression model. Gibbs sampling was used to obtain posterior distributions. The model included herd × test date, age × season of calving × stage of lactation [classes of 25 days in milk (DIM)], production sector × stage of lactation (classes of 5 DIM) as fixed effects, and random regression coefficients for additive genetic, permanent environmental, and herd-year of calving effects, which were defined as modified constant, linear, and quadratic Legendre coefficients. Heritability estimates for 305-d milk, fat and protein yields were moderate (0.12 to 0.18) and in the same range of parameters estimated in management systems with low to medium production levels. Heritabilities of test-day milk and protein yields for selected DIM were higher in the middle than at the beginning or the end of lactation. Inversely, heritabilities of fat yield were high at the peripheries of lactation. Genetic correlations among 305-d yield traits ranged from 0.50 to 0.86. The largest genetic correlation was observed between the first and second lactation, potentially due to the limited expression of genetic potential of superior cows in later lactations. Results suggested a lack of adaptation under the local management and climatic conditions. Results should be useful to implement a BLUP evaluation for the Tunisian cow population; however, results also indicated that further research focused on data quality might be needed. 相似文献
6.
Islem Rekik Stéphanie Allassonnière Olivier Clatz Ezequiel Geremia Erin Stretton Hervé Delingette Nicholas Ayache 《Computer Vision and Image Understanding》2013,117(3):238-249
Coupling time series of MR Images with reaction–diffusion-based models has provided interesting ways to better understand the proliferative-invasive aspect of glial cells in tumors. In this paper, we address a different formulation of the inverse problem: from a single time point image of a non-swollen brain tumor, estimate the tumor source location and the diffusivity ratio between white and gray matter, while exploring the possibility to predict the further extent of the observed tumor at later time points in low-grade gliomas. The synthetic and clinical results show the stability of the located source and its varying distance from the tumor barycenter and how the estimated ratio controls the spikiness of the tumor. 相似文献
7.
Ghazi Rekik Aïmen Khacharem Yosra Belkhir Naila Bali Mohamed Jarraya 《Journal of Computer Assisted Learning》2019,35(1):74-81
Recent studies exploring the effects of dynamic visualizations on learning compared with static visualizations have yielded mixed results. Procedural motor learning is one of the few fields in which dynamic representations have shown to be effective. Many of the studies have suggested that this advantage is mainly due to the activation of the “mirror‐neuron system.” This study explores this explanation in physical education domain and analysed the effects of instructional media (video vs. photographs), showing tactical actions in basketball, on learning outcomes (i.e., game understanding and game performance), cognitive load (i.e., mental effort invested and estimated difficulty), and attitudes (i.e., attention, enjoyment, engagement, and challenge) in secondary school students. For all of the indicators, the results show that learning from video was more effective than learning from photographs. These findings have implications for the effective design of instructional media and provide confirmation of the superiority of video for teaching tactical actions involving the entire body. 相似文献
8.
Rekik M. Besbes M. Marchand C. Multon B. Loudot S. Lhotellier D. 《Electric Power Applications, IET》2007,1(5):785-792
A new operation mode for switched reluctance motors (SRMs), called 'continuous mode', is described. By using this mode, the torque and then power in field-weakening mode can be considerably increased without any hardware modifications. Consequently, power and torque densities of SRMs become comparable to other technologies (synchronous and induction motors) and with a field weakening operation over a large speed range. This new degree of freedom makes it possible to improve the motor design, by modifying the rotor pole arc size or the windings turns per pole. Only simulation results are presented here, for a 12/8 SRM. Results confirm that the maximum power is improved (constant power on a very large speed range) and with a higher efficiency than that in the classical discontinuous mode. 相似文献
9.
This paper considers a shift scheduling problem that includes different forms of flexibility in terms of shift starting times, break lengths and break placement. Two particular forms are studied: fractionable breaks and work stretch duration restrictions. Unlike standard breaks, fractionable breaks are not required to be attributed as a whole. They can be divided into fractions of breaks under some conditions. The distribution of breaks within a shift is done with respect to work stretch duration restrictions to ensure a correct mix of periods of work and rest. Two implicit models are proposed. They extend previous work on implicit modeling of break placement to incorporate the concepts of fractionable breaks and work stretch duration restrictions. In this context, we show the merits of using the so-called forward and backward constraints to model work stretch duration restrictions. We also introduce a new formulation of the forward and backward constraints and demonstrate that it considerably reduces the density of the constraint matrix of the two proposed models. Finally, we study the impact of fractionable breaks and work stretch duration restrictions and show that, for some instances, the use of these concepts considerably reduces the workforce size when compared to other traditional approaches. 相似文献
10.
The electrocatalytic hydrogenation (ECH) of 2,6-dimethylphenol and 2-tert-butylphenol was performed at RaNi cathodes in aqueous buffers containing various amounts of didodecyldimethylammonium bromide (DDAB). Without surfactant, 2,6-dimethylcyclohexanol, 2-tert-butylcyclohexanone and 2-tert-butylcyclohexanol were obtained, at 65 °C, with very low yields. The surfactant effect on the yields, the selectivity of the reaction and the diastereoisomeric composition of alkylcyclohexanols produced was studied in acidic and basic solutions in relation to the substrate adsorption. At pH 9 the efficiency of the hydrogenation reaction was significantly improved by low amounts of DDAB, which led to an increase of the alkylcyclohexanols formation. In particular, cis-2-tert-butylcyclohexanol was obtained with a high diastereoselectivity. 相似文献