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991.
Glycyrrhiza uralensis (licorice) is one of the most frequently prescribed ingredients in Oriental medicine, and licorice extract has been shown to exert anti‐carcinogenic effects. However, its use as a cancer chemopreventive agent is rather limited, due to the fact that its principal component, glycyrrhizin, is known to induce hypertension. This study determined the effects of a hexane/ethanol extract of G. uralensis (HEGU), which contains undetectable amounts of glycyrrhizin, on the apoptosis of androgen‐insensitive DU145 cells. HEGU induced apoptosis and increased the levels of cleaved caspase‐9, caspase‐7, caspase‐3 and poly (ADP‐ribose) polymerase (PARP). HEGU also induced mitochondrial membrane depolarization and cytochrome c release to the cytosol. HEGU increased the levels of Fas, death receptor 4 (DR4), cleaved caspase‐8, Mcl‐1S, and truncated Bid proteins. A caspase‐8 inhibitor suppressed HEGU‐induced apoptosis. An active fraction of HEGU was separated via column chromatography and the structure of the active compound isoangustone A was identified via 1H‐NMR and 13C‐NMR. Isoangustone A increased apoptotic cells, the cleavage of PARP and caspases, and the levels of DR4 and Mcl‐1S. Transfection with DR4 small interfering RNA attenuated HEGU‐ and isoangustone A‐induced apoptosis. These results demonstrate that the activation of DR4 contributes to HEGU‐ and isoangustone A‐induced apoptosis of DU145 cells.  相似文献   
992.
Maltoheptaose (G7) and maltooctaose (G8) were examined as potential encapsulating agents for aroma compounds and compared with commercially available maltodextrins with the dextrose equivalent (DE) 10 and 18. Solutions of each encapsulating agent were homogenized with aromas and spray dried. The initial amounts of aroma compounds retained in each encapsulating agent were as follows: G7<G8≈DE 18<DE 10. During storage at 25°C, G8 was most effective at retaining the aroma compounds among 4 encapsulating agents used in this study, then followed by G7. This result may be due to the high molecular weight and uniform wall matrix composed of either pure G8 or G7 when compared to the commercial maltodextrins that had a broad distribution of molecular weights. Our results suggest that G7 and G8 can serve as excellent encapsulating agents for aroma compounds.  相似文献   
993.
西部石油管道工程黄土区冲沟,滑坡遥感图像解译   总被引:1,自引:0,他引:1  
本文建立了西部石油管道工程黄土区冲沟、滑坡解译标志,总结了区内冲沟、滑坡发育特点和形成因素,评价了区内冲沟.滑坡的稳定性.研究表明,在山区和丘陵区进行线路工程选线时,应用航空遥感图像解译是一种十分经济有效的方法.  相似文献   
994.
The aim of this paper was to investigate the effect of whey protein isolate (WPI) and polymerised whey protein isolate (WPP) addition on physicochemical properties of processed cheese with partial fat replacement. Surface properties were determined by advancing (θa) and receding (θr) contact angles, apparent free surface energy (γs). Roughness measurements, cheese meltability and Turbiscan Stability Index (TSI) were evaluated by Turbiscan. Higher WPP concentrations produced the more hydrophobic surfaces of the samples. Conversely, increase in WPI addition promoted the hydrophilic cheese surfaces. The effect of roughness was much larger for samples containing WPI. The increase in protein addition caused a decrease in meltability and an increase in stability of cheeses. The optical and confocal images have proved that cheeses with WPP demonstrated more packed and denser structure in comparison to samples with WPI.  相似文献   
995.
The year 2012 marked the 10th anniversary of publication of Presidential Decree No. 4508/2002, which set forth minimum efficiency standards for induction motors in Brazil. Within this context, the present article focuses on the importance of implementing minimum efficiency standards in Brazil and elsewhere and presents the state of the art in domestic and international legislation and standards pertaining to induction motors. It also covers advancements in motor technology, by means of an analysis of motors currently on the market, and trends in said technology, with particular emphasis on the search for new materials for permanent magnet manufacturing. The results of experimental testing of a permanent-magnet motor and a premium-efficiency induction motor are presented and discussed, with the objective of contributing to definition of the IE4 (Efficiency Level from International Electrotechnical Commission) standard and to the goal-oriented Brazilian efficiency program. The present article described the results of experimental testing with an induction motor and a line-start permanent-magnet motor and concluded that permanent-magnet motors are superior in performance to induction motors at loads between half and full, with an efficiency advantage of up to 6.7%. However, in applications with wide variations in load, with motor operation below half load, use of permanent-magnet motors is not economically feasible, as the current cost of these motors exceeds that of induction motors. Another relevant finding concerns the current harmonic distortion observed during testing. The tested permanent-magnet motor exhibited a distortion of up to 13.5%, exceeding Institute of Electrical and Electronics Engineers Standard 519/1992 recommended limits. This behavior must be clearly specified and taken into account by future standards that define the super premium class, lest the impact of harmonic distortion prove to be detrimental to industries that adopt these motors for their processes.  相似文献   
996.
Kim  Yong-Gun  Jo  Myong-Bong  Kim  Pyol  Oh  Song-Nam  Paek  Chung-Hyok  So  Sung-Ryol 《Water Resources Management》2021,35(1):135-157

In this study, a novel simulation-optimization model for the optimal flood control of the cascade barrage network was proposed by combining a simulation-based optimization method with a one-dimensional flood numerical analysis method. The simulation-based optimization method determines the optimal operation rules of cascade barrages, including the pre-discharge stage algorithm and the main-discharge stage algorithm for the securement of flood control storage and the establishment of a minimal discharge plan. The optimal operation rules describe the detailed operation process of barrage floodgates including full and partial opening and provide the upper and downstream boundary conditions for the flood numerical analysis method, which evaluate the flood propagation in the river channel between barrages. The proposed model was applied to the flood control of the six-cascade barrage network in the Taedong River, Democratic People’s Republic of Korea, and its effectiveness was verified in comparison with a well-known PSO-optimization method. The results show that the proposed model is superior to the existing other method and practically applicable to the flood control in the rivers with cascade barrage network.

  相似文献   
997.
Poly(ethylene oxide)–lithium salt composite electrolytes containing two different derivatives of calix[4]arene were tested as anion complexing agents for I and CF3SO3. Both calix[4]arene derivatives studied have identical anion coordination groups but they have different compatibility with the polymer matrix obtained by chemical linking of the oligo(ethylene oxide) chains to one of the studied calixarenes. The impedance spectroscopy studies showed that the addition of the anion receptor significantly changes the conductivity. The character of this changes strongly depends on the receptor used while the electrochemical stability of these two calixarene receptors measured by cyclic voltammetry is similar. It was also proved that addition of the anion receptor strongly changes the polymer matrix morphology and thermal behavior. By the comparison with the liquid systems which electrical properties were similar to the polymer matrix, we can assume that these changes are a result of anion–receptor interactions.  相似文献   
998.
Minimum amounts of SiO2 and CaO required for inducing abnormal grain growth in alumina were determined using ultrapure alumina (>99.999%) and sintering at 1900°C for 1 h in a contamination-free condition. The critical concentrations of silicon in cationic mole fractions in alumina were 300 ppm without calcium, 200 ppm with 10 ppm calcium, and 150 ppm with 20 ppm calcium. The critical concentration of calcium alone was 30 ppm. These concentrations seemed to match approximately the solubility limits reported in the literature, which suggested that the abnormal grain growth in commercially pure alumina was indeed related with the formation of a small amount of liquid phase during sintering.  相似文献   
999.
1000.
Surface modification of iron oxide nanoparticles (IOPs) with functional polymer can be used for the preparation of multifunction nanoprobes. The present study dealt with the preparation of glycoconjugated chitosan (GC) stabilized IOPs (GC-IOPs). GC was prepared by direct coupling of lactobionic acid (LA) on chitosan. GC was subsequently grafted onto the surface of IOPs to enhance colloid stability. X-ray diffraction (XRD), Fourier transform infrared spectrometer (FT-IR), transmission electron microscopy (TEM), dynamic light scattering (DLS), electrophoretic light scattering (ELS) and superconducting quantum interference device (SQUID) measurements were performed to investigate the properties of nanoparticles. FT-IR and XRD analysis of GC-IOPs showed that backbone and side chain functionality of chitosan and phase purity of IOPs remained intact during conjugation. TEM observations revealed that GC-IOPs were spherical (8–10 nm) but the dispersibility and stability in acetated buffer (pH 7.4) linearly increased with degree of substitution (DS) of chitosan. The specific magnetization of GC-IOPs was varied with DS from 19.50 to 41.56 emu/g. This variation in colloid stability and specific magnetization suggests that DS can be varied to tailor the degree of dispersion and magnetic properties of IOPs. The advantage of GC-IOPS is the ability to achieve a homogeneous nanosize particle distribution and specific surface functionality for bioconjugation. These characteristics make the GC-IOPs a potential candidate for biomedical research and clinical diagnosis.  相似文献   
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