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排序方式: 共有209条查询结果,搜索用时 31 毫秒
91.
Jones PJ Raeini-Sarjaz M Jenkins DJ Kendall CW Vidgen E Trautwein EA Lapsley KG Marchie A Cunnane SC Connelly PW 《Lipids》2005,40(2):169-174
Plant sterols, soy proteins, viscous fibers, and nuts are advised for cholesterol reduction, but their combined effect on
plant sterol absorption has never been tested. We assessed their combined action on serum sterols in hyperlipidemic subjects
who were following low-saturated fat diets before starting the study and who returned to these diets post-test. The 1-mon
test (combination) diet was high in plant sterols (1 g/1,000 kcal), soy protein (23 g/1,000 kcal), viscous fiber (9 g/1,000
kcal), and almonds (14 g/1000 kcal). Fasting blood was obtained for serum lipids and sterols, and erythrocytes were obtained
for fragility prior to and at 2-wk intervals during the study. The combination diet raised serum campesterol concentrations
by 50% and β-sitosterol by 27%, although these changes were not significant after Bonferroni correction; near-maximal rises
were found by the end of the first week, but no change was found in red cell fragility despite a 29% reduction in the LDL
cholesterol level. No significant associations were observed between changes in red cell fragility and blood lipids or sterols.
We conclude that plant sterols had a minimal impact on serum sterol concentrations or red cell fragility in hyperlipidemic
subjects on diets that greatly reduced their serum lipids. 相似文献
92.
Today’s technological demands require challenging control solutions such as real-time applications of Networked Control System (NCS). However, due to communication protocol and shared data bus, NCS experiences uncertain and unpredictable time delays in both input and output channels. These delays cause asynchronization between the controller and the plant thereby degrading the performance of closed-loop control systems. To address this problem, this paper proposes to utilize digital redesign technique to provide real-time random delay compensation. 相似文献
93.
Robin Augustine 《国际聚合物材料杂志》2016,65(1):28-37
Even though the biodegradability of polycaprolactone (PCL) is well established, few studies have carried out on the effect of nanofillers on the in vitro degradability of electrospun PCL membranes. Thus, the authors incorporated common nanofiller zinc oxide (ZnO) nanoparticles in electrospun PCL membranes. From the study of morphological schanges as well as the changes in crystallinity, it is clear that the ZnO nanoparticles accelerated the degradation of PCL. The FTIR results ascertain that the hydrolysis of the PCL nanofibers generates free hydroxyl and carbonyl groups in the bulk of the polymer. The tensile property of the PCL/ZnO nanocomposite membranes decreased with an increase in filler loading during degradation. 相似文献
94.
Stephen R. Schmidt Setrak K. Tanielyan Norman Marin Gabriela Alvez Robert L. Augustine 《Topics in Catalysis》2010,53(15-18):1214-1216
Net propylene glycol (1,2 propanediol) yields of up to 94% at 100% glycerol conversion have been achieved over a fixed bed Raney® Cu catalyst in trickle bed mode, at relatively low total pressure, 14 bar (200 psig), and minimal feedstock dilution (20 wt% water). The main identified byproducts are ethylene glycol and ethanol (each <2%), with methanol and 1,3 diol both <1%. The other key operating parameters for high yields are a narrow optimum in temperature (near 205 °C), and a high H2/liquid flow ratio, about 375/0.05 by volume. The effects of chromium promotion have also been studied for effects on side reactions and rates. Our evidence points to initial dehydrogenation as the rate-limiting step in a likely three step mechanism. 相似文献
95.
Sampson Agyin-Birikorang Yoana C. Newman Augustine K. Obour Gabriel N. Kasozi 《Nutrient Cycling in Agroecosystems》2012,92(1):91-105
Environmental benefits associated with reduced rates of nitrogen (N) application, while maintaining economically optimum yields
have economic and social benefits. Although N is an indispensable plant nutrient, residual soil N could leach out to contaminate
groundwater and surface water resources, particularly in sandy soils. A 2-year field study was conducted in an established
bermudagrass (Cynodon dactylon) pasture in the Lower Suwannee Watershed, Florida, to evaluate N application rates on forage yield, forage quality, and nitrate
(NO3-N) leaching in rapidly permeable upland sandy soils. Four N application rates (30, 50, 70, and 90 kg N ha−1 harvest−1) corresponding to 0.33, 0.55, 0.77 and IX, respectively, of recommended N rate (90 kg N ha−1 harvest−1) for bermudagrass hay production in Florida were evaluated vis-à-vis an unfertilized (0 N) control. Suction cups were installed
near the center of each plot at two depths (30 and 100 cm) to monitor NO3-N leaching. The grass was harvested at 28 days intervals to determine dry matter yield, N uptake, and herbage nutritive value.
Nitrogen application at the recommended rate produced the greatest total dry matter yield (~18.4 Mg ha−1 year−1), but a modeled economically optimum N rate of ~57 kg N ha−1 harvest−1 (~60% of the recommended N rate) projected an average dry matter yield of ~17.3 Mg ha−1 year−1, which represents >90% of the observed maximum yield. Nitrogen application increased nutritive quality of the grass, but
increases in N application rate above 30 kg N ha−1 did not result in significant increases in in vitro digestible organic matter concentration, and tissue crude protein was
not significant above 50 kg N ha−1. Across the sampling period, treatments with N rates ≤50 kg N ha−1 harvest−1 had leachate NO3-N concentration below the maximum contaminant limit of <10 mg l−1. Conversely, applying N at rates ≥70 kg N ha−1 harvest−1 resulted in leachate N concentration that exceeded the maximum contaminant limit, and suggest high risk of impacting groundwater
quality, if such rates are applied to soils with coarse (sand) textures. The study demonstrates that recommendation of a single
N application rate may not be appropriate under all agro-climatic conditions and, thus, a site-specific evaluation of best
N management strategy is critical. 相似文献
96.
The role of residence time distribution (RTD) in the accuracy of milling simulation is well appreciated in literature. Accordingly, the development of models that can accurately predict the RTD at various mill operating conditions would be of considerable benefit to the milling industry. In this paper, a 3-parameter RTD model has been derived using the concept of serial stirred mixers with a dead zone. The model parameters were optimized by minimizing the error between experimental tracer response data and model predictions using a MATLAB algorithm. Based on the optimum values of the model parameters, the mean residence time of slurry was evaluated and the effects of ball load volume and slurry concentration examined. The results revealed that the mean residence time of slurry inside the mill is affected to a larger extent by slurry concentration than the ball load volume. An empirical correlation was developed to predict the mean residence time as a function of slurry concentration, ball load volume and slurry feed rate. Over the range of conditions investigated, the mean residence time was observed to vary linearly with slurry concentration and ball load volume but inversely with feed flow rate. Lastly, a test case of the simulated mill product size distribution using the predicted RTD is presented displaying a close match with experimental data. 相似文献
97.
Chiang LY Padmawar PA Rogers-Haley JE So G Canteenwala T Thota S Tan LS Pritzker K Huang YY Sharma SK Kurup DB Hamblin MR Wilson B Urbas A 《Journal of materials chemistry》2010,20(25):5280-5293
We report the synthesis of a new class of photoresponsive C(60)-DCE-diphenylaminofluorene nanostructures and their intramolecular photoinduced energy and electron transfer phenomena. Structural modification was made by chemical conversion of the keto group in C(60)(>DPAF-C(n)) to a stronger electron-withdrawing 1,1-dicyanoethylenyl (DCE) unit leading to C(60)(>CPAF-C(n)) with an increased electronic polarization of the molecule. The modification also led to a large bathochromic shift of the major band in visible spectrum giving measureable absorption up to 600 nm and extended the photoresponsive capability of C(60)-DCE-DPAF nanostructures to longer red wavelengths than C(60)(>DPAF-C(n)). Accordingly, C(60)(>CPAF-C(n)) may allow 2γ-PDT using a light wavelength of 1000-1200 nm for enhanced tissue penetration depth. Production efficiency of singlet oxygen by closely related C(60)(>DPAF-C(2) (M)) was found to be comparable with that of tetraphenylporphyrin photosensitizer. Remarkably, the (1)O(2) quantum yield of C(60)(>CPAF-C(2) (M)) was found to be nearly 6-fold higher than that of C(60)(>DPAF-C(2) (M)), demonstrating the large light-harvesting enhancement of the CPAF-C(2) (M) moiety and leading to more efficient triplet state generation of the C(60)> cage moiety. This led to highly effective killing of HeLa cells by C(60)(>CPAF-C(2) (M)) via photodynamic therapy (200 J cm(-2) white light). We interpret the phenomena in terms of the contributions by the extended π-conjugation and stronger electron-withdrawing capability associated with the 1,1-dicyanoethylenyl group compared to that of the keto group. 相似文献
98.
Hemenover Scott H.; Augustine Adam A.; Shulman Tirza; Tran Tuan Q.; Barlett Christopher P. 《Canadian Metallurgical Quarterly》2008,8(4):468
The extant literature implicates affect repair ability as one source of individual differences in negative affect. Emerging from this literature are three regulatory traits that should predict repair ability (negative mood regulation expectancies, monitoring, labeling), yet no experimental examination of this possibility exists. Two studies explored this issue. Participants (Ns = 305, 146) watched negative affect-inducing videos and completed a repair or control writing task, before and after which they reported their affect. Results revealed wide individual differences in repair ability. Specifically, participants with high expectancies of repair success and those who attend to and understand their affect experienced the largest decreases in negative affect and largest increases in positive affect following the repair tasks. These findings advance understanding of individual differences in affect regulation and have implications for future research. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
99.
Deterministic Construction of Plasmonic Heterostructures in Well‐Organized Arrays for Nanophotonic Materials
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100.
Edwin P. Chan Joseph J. Walish Augustine M. Urbas Edwin L. Thomas 《Advanced materials (Deerfield Beach, Fla.)》2013,25(29):3934-3947
Polymer gels are remarkable materials with physical structures that can adapt significantly and quite rapidly with changes in the local environment, such as temperature, light intensity, electrochemistry, and mechanical force. An interesting phenomenon observed in certain polymer gel systems is mechanochromism – a change in color due to a mechanical deformation. Mechanochromic photonic gels are periodically structured gels engineered with a photonic stopband that can be tuned by mechanical forces to reflect specific colors. These materials have potential as mechanochromic sensors because both the mechanical and optical properties are highly tailorable via incorporation of diluents, solvents, nanoparticles, or polymers, or the application of stimuli such as temperature, pH, or electric or strain fields. Recent advances in photonic gels that display strain‐dependent optical properties are discussed. In particular, this discussion focuses primarily on polymer‐based photonic gels that are directly or indirectly fabricated via self‐assembly, as these materials are promising soft material platforms for scalable mechanochromic sensors. 相似文献