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排序方式: 共有2922条查询结果,搜索用时 31 毫秒
1.
Yang Hu Stephanie M. Sjoberg Chunpen Chen Amber L. Hauvermale Craig F. Morris Stephen R. Delwiche Ashley E. Cannon Camille M. Steber Zhiwu Zhang 《Comprehensive Reviews in Food Science and Food Safety》2022,21(3):2105-2117
This review examines the application, limitations, and potential alternatives to the Hagberg–Perten falling number (FN) method used in the global wheat industry for detecting the risk of poor end-product quality mainly due to starch degradation by the enzyme α-amylase. By viscometry, the FN test indirectly detects the presence of α-amylase, the primary enzyme that digests starch. Elevated α-amylase results in low FN and damages wheat product quality resulting in cakes that fall, and sticky bread and noodles. Low FN can occur from preharvest sprouting (PHS) and late maturity α-amylase (LMA). Moist or rainy conditions before harvest cause PHS on the mother plant. Continuously cool or fluctuating temperatures during the grain filling stage cause LMA. Due to the expression of additional hydrolytic enzymes, PHS has a stronger negative impact than LMA. Wheat grain with low FN/high α-amylase results in serious losses for farmers, traders, millers, and bakers worldwide. Although blending of low FN grain with sound wheat may be used as a means of moving affected grain through the marketplace, care must be taken to avoid grain lots from falling below contract-specified FN. A large amount of sound wheat can be ruined if mixed with a small amount of sprouted wheat. The FN method is widely employed to detect α-amylase after harvest. However, it has several limitations, including sampling variability, high cost, labor intensiveness, the destructive nature of the test, and an inability to differentiate between LMA and PHS. Faster, cheaper, and more accurate alternatives could improve breeding for resistance to PHS and LMA and could preserve the value of wheat grain by avoiding inadvertent mixing of high- and low-FN grain by enabling testing at more stages of the value stream including at harvest, delivery, transport, storage, and milling. Alternatives to the FN method explored here include the Rapid Visco Analyzer, enzyme assays, immunoassays, near-infrared spectroscopy, and hyperspectral imaging. 相似文献
2.
Nuclear Magnetic Resonance Investigation of the Effect of pH on Micelle Formation by the Amino Acid‐Based Surfactant Undecyl l‐Phenylalaninate 下载免费PDF全文
Gabriel A. Rothbauer Elisabeth A. Rutter Chelsea Reuter‐Seng Simon Vera Eugene J. Billiot Yayin Fang Fereshteh H. Billiot Kevin F. Morris 《Journal of surfactants and detergents》2018,21(1):139-153
Micelle formation by the anionic amino acid‐based surfactant undecyl l ‐phenylalaninate (und‐Phe) was investigated as a function of pH in solutions containing either Na+, l ‐arginine, l ‐lysine, or l ‐ornithine counterions. In each mixture, the surfactant's critical micelle concentration (CMC) was the lowest at low pH and increased as solutions became more basic. Below pH 9, surfactant solutions containing l ‐arginine and l ‐lysine had lower CMC than the corresponding solutions with Na+ counterions. Nuclear magnetic resonance (NMR) diffusometry and dynamic light scattering studies revealed that und‐Phe micelles with Na+ counterions had hydrodynamic radii of approximately 15 Å throughout the investigated pH range. Furthermore, l ‐arginine, l ‐lysine, and l ‐ornithine were found to bind most strongly to the micelles below pH 9 when the counterions were cationic. Above pH 9, the counterions became zwitterionic and dissociated from the micelle surface. In und‐Phe/l ‐arginine solution, counterion dissociation was accompanied by a decrease in the hydrodynamic radius of the micelle. However, in experiments with l ‐lysine and l ‐ornithine, micelle radii remained the same at low pH when counterions were bound and at high pH when they were not. This result suggested that l ‐arginine is attached perpendicular to the micelle surface through its guanidinium functional group with the remainder of the molecule extending into solution. Contrastingly, l ‐lysine and l ‐ornithine likely bind parallel to the micelle surface with their two amine functional groups interacting with different surfactant monomers. This model was consistent with the results from two‐dimensional ROESY (rotating frame Overhauser enhancement spectroscopy) NMR experiments. Two‐dimensional NMR also showed that in und‐Phe micelles, the aromatic rings on the phenylalanine headgroups were rotated toward the hydrocarbon core of micelle. 相似文献
3.
S.R.O. Williams A.V. Chaves M.H. Deighton J.L. Jacobs M.C. Hannah B.E. Ribaux G.L. Morris W.J. Wales P.J. Moate 《Journal of dairy science》2018,101(3):2072-2083
Almond hulls and citrus pulp have been fed to dairy cows with variable responses for milk production, but no information exists on their effect on enteric methane emissions. This experiment examined the effects of dietary supplementation with either almond hulls or ensiled citrus pulp on the milk yield, milk composition, and enteric methane emissions of dairy cows. Thirty-two Holstein dairy cows in mid lactation were offered 1 of 3 diets over a 28-d experiment. Twelve cows received a control (CON) diet, 10 cows a diet containing almond hulls (ALH), and 10 cows a diet containing ensiled citrus pulp (CIT). All cows were offered 6.0 kg of dry matter (DM)/d of crushed corn, 2.0 kg of DM/d of cold-pressed canola, and 0.2 kg of DM/d of a mineral mix. In addition, cows fed the CON diet were offered 14.5 kg of DM/d of alfalfa cubes; cows fed the ALH diet were offered 10.5 kg of DM/d of alfalfa cubes and 4.0 kg of DM/d of almond hulls; and cows on the CIT diet were offered 11.5 kg of DM/d of alfalfa cubes and 3.0 kg of DM/d of ensiled citrus pulp. Milk yield was measured daily and milk composition was measured on 4 d of each week. Individual cow methane emissions were measured by a sulfur hexafluoride tracer technique on d 24 to 28 of the experiment. The mean milk yield of cows fed the CON diet (27.4 kg/d) was greater than the mean milk yield of cows fed the ALH diet (24.6 kg/cow per day), whereas the mean milk yield of cows fed the CIT diet (26.2 kg/cow per day) was not different from the mean milk yield from cows fed the other 2 diets. Dietary treatment did not influence the concentrations of milk fat, protein, and lactose or fat yields, but the mean protein yield from cows fed the CON diet (0.87 kg/d) was greater than that from cows fed the ALH diet (0.78 kg/d) but not different to those fed the CIT diet (0.85 kg/d). In general, we found no differences in the proportion of individual fatty acids in milk. The mean pH of ruminal fluid from cows offered the CON diet was not different to the pH in the ruminal fluids of cows offered the ALH or the CIT diets. The mean methane emissions (g/d) and yields (g/kg of DM intake) were not influenced by dietary treatment. These findings indicate that, although almond hulls and ensiled citrus pulp can be used as a low-cost feed supplement, almond hulls did negatively affect milk production and neither inhibited enteric methane emissions. 相似文献
4.
Sonar emits pulses of sound and uses the reflected echoes to gain information about target objects. It offers a low cost, complementary sensing modality for small robotic platforms. Although existing analytical approaches often assume independence across echoes, real sonar data can have more complicated structures due to device setup or experimental design. In this article, we consider sonar echo data collected from multiple terrain substrates with a dual-channel sonar head. Our goals are to identify the differential sonar responses to terrains and study the effectiveness of this dual-channel design in discriminating targets. We describe a unified analytical framework that achieves these goals rigorously, simultaneously, and automatically. The analysis was done by treating the echo envelope signals as functional responses and the terrain/channel information as covariates in a functional regression setting. We adopt functional mixed models that facilitate the estimation of terrain and channel effects while capturing the complex hierarchical structure in data. This unified analytical framework incorporates both Gaussian models and robust models. We fit the models using a full Bayesian approach, which enables us to perform multiple inferential tasks under the same modeling framework, including selecting models, estimating the effects of interest, identifying significant local regions, discriminating terrain types, and describing the discriminatory power of local regions. Our analysis of the sonar-terrain data identifies time regions that reflect differential sonar responses to terrains. The discriminant analysis suggests that a multi- or dual-channel design achieves target identification performance comparable with or better than a single-channel design. Supplementary materials for this article are available online. 相似文献
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7.
Kothandaraman Mohanaprasad Law Zijian Ezra Morris A. G. Pua Chang Hong Rajasekaran Uma 《Water Resources Management》2022,36(6):1973-1989
Water Resources Management - The localization of the leaks is estimated using the time difference method in the past decade. Generalized and Basic Cross-correlation techniques are frequently... 相似文献
8.
Flynn Castles Julian A. J. Fells Dmitry Isakov Stephen M. Morris Andrew A. R. Watt Patrick S. Grant 《Advanced materials (Deerfield Beach, Fla.)》2020,32(9):1904863
Although well-established textbook arguments suggest that static electric susceptibility χ(0) must be positive in “all bodies,” it has been pointed out that materials that are not in thermodynamic equilibrium are not necessarily subject to this restriction. Media with inverted populations of atomic and molecular energy levels have been predicted theoretically to exhibit a χ(0) < 0 state, however the systems envisioned require reduced temperature, reduced pressure, and an external pump laser to maintain the population inversion. Further, the existence of χ(0) < 0 has never been confirmed experimentally. Here, a completely different approach is taken to the question of χ(0) < 0 and a design concept to achieve “true” χ(0) < 0 is proposed based on active metamaterials with internal power sources. Two active metamaterial structures are fabricated that, despite still having their power sources implemented externally for reasons of practical convenience, provide evidence in support of the general concept. Effective values are readily achieved at room temperature and pressure and are tunable throughout the range of stability −1 < χ(0) < 0, resulting in experimentally-determined magnitudes that are over one thousand times greater than those predicted previously. Since χ(0) < 0 is the missing electric analog of diamagnetism, this work opens the door to new technological capabilities such as stable electrostatic levitation. 相似文献
9.
Morris M. H. Hsu Pei-Yu Huang Yao-Chang Lee Yuang-Chuen Fang Michael W. Y. Chan Cheng-I Lee 《International journal of molecular sciences》2014,15(10):17963-17973
Ovarian cancer, as well as other cancers, is primarily caused by methylation at cytosines in CpG islands, but the current marker for ovarian cancer is low in sensitivity and failed in early-stage detection. Fourier transform infrared (FT-IR) spectroscopy is powerful in analysis of functional groups within molecules, and infrared microscopy illustrates the location of specific groups within single cells. In this study, we applied HPLC and FT-IR microspectrometry to study normal epithelial ovarian cell line immortalized ovarian surface epithelium (IOSE), two epithelial ovarian cell lines (A2780 and CP70) with distinct properties, and the effect of a cancer drug 5-aza-2''-deoxycytidine (5-aza) without labeling. Our results reveal that inhibition of methylation on cytosine with 5-aza initiates the protein expression. Furthermore, paraffin-adsorption kinetic study allows us to distinguish hypermethylated and hypomethyated cells, and this assay can be a potential diagnosis method for cancer screening. 相似文献
10.
Craig F. Morris E. Patrick Fuerst Derek J. McLean Kathleen Momont Caleb P. James 《Journal of food science》2014,79(11):S2323-S2329
Wheat (Triticum aestivum L.) plays a central role in the health and nutrition of humans. Yet, little is known about possible flavor differences among different varieties. We have developed a model system using the house mouse (Mus musculus L.) to determine feeding preferences as a prelude to extending results to human sensory analysis. Here, we examine the application of a single‐elimination tournament design to the analysis of consumption preferences of a set of hard red and hard white spring wheat varieties. A single‐elimination tournament design in this case pairs 2 wheat varieties and only 1 of the 2 is advanced to further tests. Preferred varieties were advanced until an overall “winner” was identified; conversely, less desirable varieties were advanced such that an overall “loser” was identified. Hollis and IDO702 were the winner and loser, respectively, for the hard red varieties, and Clear White 515 and WA8123 were the winner and loser, respectively, for the hard white varieties. When using the more powerful protocol of 14 mice and a 4?d trial, differences in mean daily consumption preferences of 2 varieties were separated at P‐values as small as 2 × 10?8. The single‐elimination tournament design is an efficient means of identifying the most and least desirable varieties among a larger set of samples. One application for identifying the 2 extremes in preference within a group of varieties would be to use them as parents of a population to identify quantitative trait loci for preference. 相似文献