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排序方式: 共有600条查询结果,搜索用时 15 毫秒
81.
Shanmugam K Holmquist L Steele M Stuchbury G Berbaum K Schulz O Benavente García O Castillo J Burnell J Garcia Rivas V Dobson G Münch G 《Molecular nutrition & food research》2008,52(4):427-438
Lipopolysaccharides released during bacterial infections induce the expression of pro-inflammatory cytokines and lead to complications such as neuronal damage in the CNS and septic shock in the periphery. While the initial infection is treated by antibiotics, anti-inflammatory agents would be advantageous add-on medications. In order to identify such compounds, we have compared 29 commercially available polyphenol-containing plant extracts and pure compounds for their ability to prevent LPS-induced up-regulation of NO production. Among the botanical extracts, bearberry and grape seed were the most active preparations, exhibiting IC(50) values of around 20 mug/mL. Among the pure compounds, IC(50) values for apigenin, diosmetin and silybin were 15, 19 and 12 muM, in N-11 murine microglia, and 7, 16 and 25 muM, in RAW 264.7 murine macrophages, respectively. In addition, these flavonoids were also able to down-regulate LPS-induced tumour necrosis factor production. Structure-activity relationships of the flavonoids demonstrated three distinct principles: (i) flavonoid-aglycons are more potent than the corresponding glycosides, (ii) flavonoids with a 4'-OH substitution in the B-ring are more potent than those with a 3'-OH-4'-methoxy substitution, (iii) flavonoids of the flavone type (with a C2=C3 double bond) are more potent than those of the flavanone type (with a at C2-C3 single bond). 相似文献
82.
There are great interests to capture the CO_2 to control the greenhouse gas emission. Amine absorption of CO_2 is being taken as an effective way to capture CO_2 in industry. However, the amine absorption of CO_2 is cost-ineffective due to great energy consumption and solution consumption. In order to reduce the capture cost, catalyst fluidization is proposed here to intensify the mass transfer and heat transfer. Catalyst fluidization with field synergy and DFT model is developed by incorporating the effects of catalyst reaction kinetics, drag force and multi-field into the mass transfer, heat transfer, fluid flow and catalyst collision. Experiments with an improved distributor are performed well to validate the model. The reaction kinetics is determined by the DFT simulation and experiment. The mass transfer coefficient in the fluidized reactor is identified as 17% higher than the conventional packed reactor. With the field synergy of catalyst fluidization, the energy consumption for CO_2 desorption is reduced by 9%. Stepwise operation and inclination reactor are used to improve catalyst fluidization process. 相似文献
83.
Bárbara E. Meza Amy K.S. ChestertonRoxana A. Verdini Amelia C. RubioloPeter A. Sadd Geoff D. MoggridgeD. Ian Wilson 《Journal of food engineering》2011,104(4):592-602
The rheological behaviour of high ratio cake batters prepared with untreated and heat-treated wheat flours was analysed at different stages of the manufacturing process, namely slurry, (on aeration) foams and (with fat addition) aerated emulsions, featuring air volume fractions up to 0.50. Both steady shear and viscoelastic behaviours were studied. All materials exhibited shear-thinning behaviour at 20 °C over the shear rate range studied (0.07-10 s−1). The generalised Cox-Merz rule could be applied to all samples. Materials prepared with heat-treated flours exhibited greater stability, as indicated by slurry thixotropy and cohesive energy, and the change in apparent viscosity and air content of foams and aerated emulsions on extended mixing. Foams and aerated emulsions showed significant elastic behaviour with G′∼G″. The temperature dependency of aerated emulsions was studied by oscillatory shear testing from 20 to 100 °C and indicated three regimes in temperature dependence: below 40 °C G′and G″ were insensitive to temperature; between 40 and 70 °C the complex viscosity exhibited Arrhenius-type behaviour, while above 70 °C G′ and G″ increased as expected for gelatinisation and foam setting. The weak gel model for foods was used to analyse the latter data sets and confirmed that the gel network generated in aerated emulsions prepared with heat-treated flours was significantly stronger than those made with unheated flours. The differences between flour types were also observed in tests on un- and heat-treated flours obtained from a second and third harvest. The impact of these quantifiable differences in rheology on performance during baking is discussed. 相似文献
84.
Yang Daiwei Wang Wei Li Jingxuan Xu Runsheng Wang Xianzhen Wang Geoff 《Metallurgical and Materials Transactions B》2020,51(2):776-785
Metallurgical and Materials Transactions B - Al2O3 greatly influences the formation of complex calcium ferrite, which is the main binder and iron-bearing phase in sinter. Experiments were carried... 相似文献
85.
Heitor M. Gomes Albert Bifet Jesse Read Jean Paul Barddal Fabrício Enembreck Bernhard Pfharinger Geoff Holmes Talel Abdessalem 《Machine Learning》2017,106(9-10):1469-1495
Random forests is currently one of the most used machine learning algorithms in the non-streaming (batch) setting. This preference is attributable to its high learning performance and low demands with respect to input preparation and hyper-parameter tuning. However, in the challenging context of evolving data streams, there is no random forests algorithm that can be considered state-of-the-art in comparison to bagging and boosting based algorithms. In this work, we present the adaptive random forest (ARF) algorithm for classification of evolving data streams. In contrast to previous attempts of replicating random forests for data stream learning, ARF includes an effective resampling method and adaptive operators that can cope with different types of concept drifts without complex optimizations for different data sets. We present experiments with a parallel implementation of ARF which has no degradation in terms of classification performance in comparison to a serial implementation, since trees and adaptive operators are independent from one another. Finally, we compare ARF with state-of-the-art algorithms in a traditional test-then-train evaluation and a novel delayed labelling evaluation, and show that ARF is accurate and uses a feasible amount of resources. 相似文献
86.
The moisture sorption of poly(p-phenylene terephthalamide) (PPTA) fibers and the effects of moisture on the wetting behavior of these fibers in water and in an epoxy resin were studied. The moisture regains in the Kevlar 149 fibers followed a third order polynomial dependency on increasing relative humidity at 23°C. When preconditioned at 0% relative humidity (R.H.), water wettability of Kevlar 49 fibers was superior to that of Kevlar 149 fibers. Resin wettability of the dried Kevlar 49 fibers, on the other hand, was lower than that of Kevlar 149 fibers. Wettability in water and resin of these two fiber types was affected differently by moisture. Exposure to 97% R.H. moisture level significantly lowered water wettability of Kevlar 49 fibers but did not affect the wettability of Kevlar 149 fibers in water. Resin wettability of Kevlar 49 fibers was improved upon exposure to moisture, but the opposite was observed on Kevlar 149 fibers. 相似文献
87.
88.
89.
Paul Elliott PhD MA David. C. Aldridge MA PhD Geoff D. Moggridge BSc PhD Michael Chipps BSc PhD 《Water and Environment Journal》2005,19(4):367-375
The zebra mussel, Dreissena polymorpha, is a major biofouling pest of water treatment works, irrigation systems and power stations in Europe and North America. This paper documents current problems associated with zebra mussels in English waterworks. Questionnaires and manual surveys conducted between 2001 and 2003 have revealed that over 30 water treatment works in England suffer problems associated with zebra mussels. Hundreds of tonnes of mussels are being removed each year from raw water intakes, pipelines and reservoirs. Problems have increased in. the last five years, due to a spread in the range of zebra mussels around England and the cessation of chemical treatment at the intakes of many treatment facilities during the 1990s. The importance of taking control of zebra mussels into account in planning new water supply schemes is highlighted. 相似文献
90.
Near-Surface Wind-Induced Mixing in a Mine Lake 总被引:2,自引:0,他引:2
Anita Huber Gregory N. Ivey Geoff Wake Carolyn E. Oldham 《Canadian Metallurgical Quarterly》2008,134(10):1464-1472
Wind sheltering can have a strong effect in small, sheltered water bodies; wind-induced mixing in the surface layer of a small mine lake has been investigated using field measurements. Wind speed was recorded at three locations and data suggested sheltering by topography and surface roughness changes with both fetch and the land–water transition. Wind sheltering effects in the near-surface waters were assessed using turbulent microstructure profiler measurements, providing an estimate of the sheltering distance consistent with the literature on “backward-facing” steps. A numerical simulation of the annual density stratification cycle was then performed, using the model DYRESM. Simulations indicated that inclusion of a sheltering algorithm based on the results of the field campaign significantly improved the model’s performance in capturing the surface mixed layer deepening associated with strong wind events. 相似文献