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T Ojasoo E Bignon A Crastes de Paulet JC Doré J Gilbert JF Miquel M Pons JP Raynaud 《Canadian Metallurgical Quarterly》1993,44(3):239-250
A multivariate statistical method, correspondence factorial (CF) analysis, was used to examine the correlations among the protein binding and cell proliferation effects of a series of 36 di- and triphenylethylenes (DPEs and TPEs). The analysis was applied to a study which measured their competition for estradiol binding to cytosol estrogen receptor (ER), their influence on protein kinase C (PKC) activity under different conditions of enzyme activation, their ability to promote the growth of a breast cancer cell line and to inhibit growth at high concentrations (cytotoxicity). The CF analysis revealed several levels of correlation. First, it distinguished those molecules within the population that stimulated rather than inhibited PKC activity. Second, it made apparent a strong correlation between cytotoxicity and inhibition of Ca++ and phosphatidylserine-dependent PKC activity, which was most marked when the enzyme had been activated by diacylglycerol indicating that PKC inhibition under physiological conditions might contribute to the overall cytotoxicity of these compounds. Third, a lower level of correlation was established between competition for ER binding and cytotoxicity. Taken together, the results suggest that MCF7 cells might be most sensitive to a cytotoxic effect of TPEs (via PKC and other targets) when they at the same time decrease estrogen-stimulated proliferation via an ER-mediated antiestrogenic effect. 相似文献
3.
This paper focuses on the harmonization of feed-in laws in the European Union as a support mechanism for the promotion of renewable electricity. In particular, it proposes a methodology for harmonization based on a feed-in law with a modular and transparent premium for renewable electricity producers. This premium considers technology costs, some grid services, political incentives and national priorities. The proposed approach includes flexibility mechanisms to update and revise premiums, to avoid windfall profits for producers, and to share technology innovation benefits with electricity consumers while maintaining incentives for innovation. Our approach is based on the review of the main features of the German and Spanish feed-in laws, and takes into account other necessary considerations for harmonization, such as grid access, funding, definitions and standards, ownership of rights derived from renewables, and exceptions for small non-commercial producers and energy-intensive industries. 相似文献
4.
Dr. Saeed Chashmniam Dr. João M. C. Teixeira Prof. Juan Carlos Paniagua Prof. Miquel Pons 《Chembiochem : a European journal of chemical biology》2021,22(6):1001-1004
Coupling of side chain dynamics over long distances is an important component of allostery. Methionine side chains show the largest intrinsic flexibility among methyl-containing residues but the actual degree of conformational averaging depends on the proximity and mobility of neighboring residues. The 13C NMR chemical shifts of the methyl groups of methionine residues located at long distances in the same protein show a similar scaling with respect to the values predicted from the static X-ray structure by quantum methods. This results in a good linear correlation between calculated and observed chemical shifts. The slope is protein dependent and ranges from zero for the highly flexible calmodulin to 0.7 for the much more rigid calcineurin catalytic domain. The linear correlation is indicative of a similar level of side-chain conformational averaging over long distances, and the slope of the correlation line can be interpreted as an order parameter of the global side-chain flexibility. 相似文献
5.
Effects of allelochemicals on plant respiration and oxygen isotope fractionation by the alternative oxidase 总被引:8,自引:1,他引:8
The goal of this investigation was to determine the effects of allelochemicals on plant respiration that thereby may be responsible for their role in growth inhibition. We have tested the effects of juglone, quercetin, cinnamic acid, and-pinene on respiration rates, and electron partitioning through the cytochrome and alternative respiratory pathways, by measuring on-line oxygen consumption and oxygen isotope fractionation in soybean cotyledon tissue. Cinnamic acid and-pinene decreased the oxygen consumption rate and increased the relative partitioning of electron transport to the alternative pathway. Possible biochemical mechanisms of these effects are discussed. 相似文献
6.
Information diffusion in large-scale networks has been studied to identify the users influence. The influence has been targeted as a key feature either to reach large populations or influencing public opinion. Through the use of micro-blogs, such as Twitter, global influencers have been identified and ranked based on message propagation (retweets). In this paper, a new application is presented, which allows to find first and classify then the local influence on Twitter: who have influenced you and who have been influenced by you. Until now, social structures of tweets’ original authors that have been either retweeted or marked as favourites are unobservable. Throughout this application, these structures can be discovered and they reveal the existence of communities formed by users of similar profile (that are connected among them) interrelated with other similar profile users’ communities. 相似文献
7.
K. J. Williams A. B. Boffa M. Salmeron A. T. Bell G. A. Somorjai 《Catalysis Letters》1991,9(5-6):415-426
Submonolayer deposits of titania on a Rh foil have been found to increase the rate of CO2 hydrogenation. The primary product, methane, exhibits a maximum rate at a TiO
x
coverage of 0.5 ML which is a factor of 15 higher than that over the clean Rh surface. The rate of ethane formation displays a maximum which is 70 times that over the unpromoted Rh foil; however, the selectivity for methane remains in excess of 99%. The apparent activation energy for methane formation and the dependence of the rate on H2 and CO2 partial pressure have been determined both for the bare Rh surface and the titania-promoted surface. These rate parameters show very small variations as titania is added to the Rh catalyst. The methanation of CO2 is proposed to start with the dissociation of CO2 into CO(a) and O(a), and then proceed through steps which are identical to those for the hydrogenation of CO. The increase in the rate of CO2 hydrogenation in the presence of titania is attributed to an interaction between the adsorbed CO, released by CO2 dissociation, and Ti3+ ions located at the edge of TiO
x
islands covering the surface. Differences in the effects of titania promotion on the methanation of CO2 and CO are discussed in terms of the mechanisms that have been proposed for these two reactions. 相似文献
8.
The mechanism of stress corrosion cracking (SCC) of Cu-30Au in 0.6 M NaCl was investigated by a series of experiments in which samples were de-alloyed by potentiostatic anodic polarization at 475 mV (Ag/AgCl) and at zero applied stress (i) for varying lengths of time (10 to 30 min) and then impact bent, and (ii) for 30 min followed by a period of time (5–30 s) at the open circuit potential and then impact bent, and (iii) for 30 min followed by anodic polarization at +150 mV (Ag/AgCl) for a period of time (5–30) and then impact bent. The results indicate that de-alloying at zero applied stress produces a surface layer that is capable for a brief period of time of inducing intergranular cleavage failure of the normally ductile substrate. In addition, samples were de-alloyed and simultaneously stressed at various nominal values (0.5–1.7 σy). At low values of stress, failure occurred by brittle intergranular cracking, and at high values of stress, failure occurred by brittle transgranular cracking. The results indicate that the electrochemical contribution to the SCC of Cu-30Au in 0.6 M NaCl is the same for both intergranular stress corrosion cracking (IGSCC) and transgranular stress corrosion cracking (TGSCC) and that the mode of fracture is dictated by the magnitude of the applied stress. 相似文献
9.
Carlos Ansótegui Miquel Bofill Miquel Palahí Josep Suy Mateu Villaret 《Constraints》2013,18(2):236-268
We introduce WSimply, a new framework for modelling and solving Weighted Constraint Satisfaction Problems (WCSP) using Satisfiability Modulo Theories (SMT) technology. In contrast to other well-known approaches designed for extensional representation of goods or no-goods, and with few declarative facilities, our approach aims to follow an intensional and declarative syntax style. In addition, our language has built-in support for some meta-constraints, such as priority and homogeneity, which allows the user to easily specify rich requirements on the desired solutions, such as preferences and fairness. We propose two alternative strategies for solving these WCSP instances using SMT. The first is the reformulation into Weighted SMT (WSMT) and the application of satisfiability test based algorithms from recent contributions in the Weighted Maximum Satisfiability field. The second one is the reformulation into an operation research-like style which involves an optimisation variable or objective function and the application of optimisation SMT solvers. We present experimental results of two well-known problems: the Nurse Rostering Problem (NRP) and a variant of the Balanced Academic Curriculum Problem (BACP), and provide some insights into the impact of the addition of meta-constraints on the quality of the solutions and the solving time. 相似文献
10.
Jos Miquel Cabeas Rute Jorge Milho 《International Journal of Industrial Ergonomics》2011,41(3):289-297
The objective of this article is to analyze the levels of forearm muscular contraction associated with the use of anti-vibration gloves, in which the contraction levels with gloves and without gloves are compared. Two different vibrating tools - a Bosch Compact Duty Multi-Cutter and a Bosch Rotary Hammer carrying an Ø20 mm bit - were used in a simulated work environment. Standard operations were performed by each subject (n = 14) in an 80 × 40 mm pine bar (cross-sectional cuts with the Multi-Cutter) and on a concrete slab 2 × 2 m, 70 mm thick (20 mm holes with the Rotary Hammer). The forearm muscular efforts were measured by surface electromyography (EMG) in four different muscles: the flexor digitorum superficialis (FDS), flexor carpi ulnaris (FCU), extensor carpi radialis longus (ECRL) and extensor carpi ulnaris (ECU). For the flexor muscles (FDS and FCU), a decrease tendency (p > 0.05) in the measured EMG was observed when the operations are performed with gloves relative to the bare hand (a reduction of 5-23% in the percentage of maximum voluntary exertion (%MVE)). For the extensor muscles (ECU), a tendency toward increased (p > 0.05) muscular contraction was observed when the operations were performed with gloves (an increase of 3-20% in the %MVE). No such tendency was found in the ECRL muscle. The ECU was the muscle with the highest %MVE for 10 and 11 operators (n = 14), during the operations, respectively, with the Multi-Cutter and the Rotary Hammer. As a final conclusion from the study, anti-vibration gloves may increase forearm fatigue in the posterior forearm (ECU muscle) and decrease forearm fatigue in the FDS muscle during operations with the above-mentioned tools.