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排序方式: 共有828条查询结果,搜索用时 15 毫秒
81.
Maike Timm‐Heinrich Xuebing Xu Nina Skall Nielsen Charlotte Jacobsen 《European Journal of Lipid Science and Technology》2003,105(8):436-448
Traditional sunflower oil (SO), randomized lipid (RL) and specific structured lipid (SL), both produced from SO and tricaprylin/caprylic acid, respectively, were stored for up to 12 wk to compare their oxidative stabilities by chemical and sensory analyses. Furthermore, the effect of adding a commercial antioxidant blend Grindox 117 (propyl gallate/ citric acid/ascorbyl palmitate) or gallic acid to the SL was investigated. The lipid type affected the oxidative stability: SL was less stable than SO and RL. The reduced stability was most likely caused by both the structure of the lipid and differences in production/ purification, which caused lower tocopherol content and higher initial levels of primary and secondary oxidation products in SL compared with RL and SO. Grindox 117 and gallic acid did not exert a distinct antioxidative effect in the SL oil samples during storage. 相似文献
82.
83.
The expansion of district heating into areas of low heat densities (heat sparse areas) constitutes a challenge due to the higher distribution costs. The profitability of sparse district heating has been analysed from actual investments in 74 areas with 3227 one-family houses connected to district heating between 2000 and 2004 in Göteborg, Sweden. The profitability was estimated from a probable price model, a typical marginal heat generation cost, and the investments from the actual connections made. The analysis identified factors as the linear heat density and heat sold per house explaining the main variations in profitability. The profitability analysis was concluded with a competition analysis. The main conclusion is that sparse district heating is possible when reaching low investment costs for the local distribution network and low marginal costs for the heat generation. In Sweden, the general competitiveness of sparse district heating is facilitated by the high consumption taxes for fuel oil, natural gas, and electricity. Hence, it should be more difficult to introduce sparse district heating in other countries with low energy taxes. 相似文献
84.
Evolutionary stable strategy (ESS) theory was tested on the handedness composition of major league baseball (MLB) players. The throwing handedness of pitchers and the hitting handedness of batters were sampled over 110 yrs and their proportions analyzed over decades. Then, to predict steady-state laterality levels, ESS equations were derived from a payoff matrix of hitting performances for left-right pitcher-batter confrontations (J. Thorn and P. Palmer, 1985). The equations successfully predicted a pitcher-batter invasion in which left-handed pitchers would stabilize at about 31% of the population. For batters, the predictions were 27% left-handed, 11% bats with both hands, and 63% right-handed, accurate within a 3% margin of error. These successful predictions, based on nonarbitrary common-currency values in the payoff matrix, support the validity of ESS, while the use of handedness, a behavior influenced by phylogenetic, ontogenetic, and cultural factors, establishes its generality. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
85.
40 parents of younger and older hyperactives (Hs; aged 5 yrs 1 mo and 8 yrs 4 mo, respectively) and 51 parents of age-matched normal controls completed measures of hyperactivity and child behavior, parenting self-esteem (PSE), and parenting stress. PSE was lower in parents of Hs than in parents of controls. Self-esteem related to skill/knowledge as a parent was age related, with parents of older Hs reporting the lowest levels; self-esteem related to valuing/comfort in the parenting role was not related to the child's age. Mothers of Hs, especially younger ones, reported markedly higher levels of stress associated with both child characteristics and their own feelings, such as depression, self-blame, and social isolation. Consistent inverse relationships were found between PSE and perceptions of child problems, whereas ratings of child disturbance and maternal stress were positively correlated. Findings are discussed in terms of the social contexts surrounding hyperactivity and the need for multidimensional assessments and interventions in families of Hs. (47 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
86.
Contends that the ideal program of research to maximize clinical relevance combines 4 models of strategies. These are (1) convergent/convergent, (2) divergent/divergent, (3) divergent-theory/convergent-method, and (4) convergent-theory/divergent-method, and all are employed nomothetically at the level of theory and idiographically at the level of method. Model 1 serves to expand theoretical and procedural possibilities, giving clinicians the flexibility they need when working with individuals in service-delivery settings. Model 2 controls theoretical expansion. Model 3 controls procedural expansion. Model 4 may be used to provide preliminary demonstrations of feasibility that are then used to stimulate other forms of more directly relevant investigation. The products of this overall program of research will increasingly represent a useful body of tested theoretical and procedural possibilities and alternatives that clinicians can use for explaining and treating individual clients and for evaluating treatment outcomes in individually relevant terms. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
87.
Local operators are used to detect linear features in Landsat data for an area where such features are typically less than 1 pixel in width. A modification to existing techniques is made which gives improved results. The choice of threshold for the detector algorithm is investigated by considering line and background intensity, linewidths, and line alignment with respect to the pixel boundaries and spatial autocorrelation in the data set. It is found that results will always contain a significant amount of noise. Two postprocessing techniques are described which reduce this noise by utilizing contextual information in the data. 相似文献
88.
Tao Wang Rósa Jónsdóttir Hordur G. Kristinsson Gudjon Thorkelsson Charlotte Jacobsen Patricia Yuca Hamaguchi Gudrún Ólafsdóttir 《Food chemistry》2010
The effects of Fucus vesiculosus extract and fractions towards haemoglobin- (Hb-) catalysed lipid oxidation in washed cod muscle system and cod protein isolates during ice storage were examined. The extract and fractions were characterised in terms of total phlorotannin content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, ferrous ion-chelating ability and reducing power. Progression of oxidation was followed by determining rancid odour, thiobarbituric acid reactive substances (TBARS), redness and volatile oxidation compounds by gas chromatography (GC). In both washed cod muscle and protein isolates, phlorotannin-enriched ethyl acetate (EtOAc) fraction showed higher inhibitory effect than crude 80% ethanol (EtOH) extract. The addition of oligomeric phlorotannin-rich subfraction (LH-2) separated by Sephadex LH-20 chromatography, completely inhibited the initiation of lipid peroxidation in both systems throughout the entire study period (8 days). Its effectiveness at 300 mg/kg level was comparable to that of 100 mg/kg propyl gallate (PG), a highly effective synthetic antioxidant in muscle foods. Although polymeric phlorotannin-rich subfraction (LH-5) had similar level of TPC and chemical antioxidant activities as oligomeric subfraction LH-2, it was far less efficient in model systems. These results suggest that other factors rather than the intrinsic reactivity toward radicals could be responsible for the inhibitory effect of phlorotannins on lipid oxidation in fish muscle. This study highlights the great potential of oligomeric phlorotannins as novel natural antioxidants in fish and fish products. 相似文献
89.
Michael J. Frampton Giuseppe Sforazzini Sergio Brovelli Gianluca Latini Emily Townsend Charlotte C. Williams Ana Charas Leszek Zalewski Naeem S. Kaka Mallena Sirish Lisa J. Parrott Joanne S. Wilson Franco Cacialli Harry L. Anderson 《Advanced functional materials》2008,18(21):3367-3376
Hydrophilic polyanionic conjugated polyrotaxanes are readily synthesized in water by Suzuki coupling, but their high polarity and ionic nature limit the potential applications of these materials. Here, we demonstrate three methods for transforming these polar polyelectrolytes into nonpolar lipophilic insulated molecular wires. A water‐soluble polyfluorene‐alt‐biphenylene β‐cyclodextrin (CD) polyrotaxane was converted into nonpolar derivatives by methylation of the carboxylic acid groups with diazomethane and conversion of the hydroxyl groups of the CDs to benzyl ethers, trihexylsilyl ethers, benzoyl esters, and butanoate esters to yield polyrotaxanes that are soluble in organic solvents such as chloroform and cyclohexane. Elemental analysis, NMR spectroscopy, and gel permeation chromatography (GPC) data support the proposed structures of the organic‐soluble polyrotaxanes. The extents of reaction of the polyrotaxane CD hydroxyl groups were 55% for trihexylsilyl chloride/imidazole; 81% for benzyl chloride/sodium hydride; 72% for benzoyl chloride/pyridine/4‐dimethylaminopyridine; and 98% butanoic anhydride/pyridine/4‐dimethylaminopyridine. Alkylation, silylation, and esterification increase the bulk of the encapsulating sheath, preventing interstrand aggregation, increasing the photoluminescence efficiency in the solid state and simplifying the time‐resolved fluorescence decay. The organic‐soluble polyrotaxanes were processed into polymer light‐emitting diodes (PLEDs) from solution in nonpolar organic solvents, thereby excluding ionic impurities from the active layer. 相似文献
90.
Mette Kristensen Lars F Østergaard Ulrich Halekoh Henry Jørgensen Charlotte Lauridsen Kirsten Brandt Susanne Bügel 《Journal of the science of food and agriculture》2008,88(12):2161-2172
BACKGROUND: Many consumers perceive organic foods as more nutritious than conventional foods. However, the existing evidence is insufficient to support or refute this belief. The purpose of the present study was to investigate the effect of three different model cultivation systems on selected major and trace element contents of dried foodstuffs (carrots, kale, peas, potatoes and apples) grown in two consecutive years, as well as mineral retention determined in 36 rats (second generation in a multi‐generation study) fed diets based on these foodstuffs from one year. RESULTS: Overall, there was no evident trend towards differences in element content of foodstuffs or diets due to the use of different cultivation systems, and differences between harvest years exceeded those seen between cultivation methods. Also, no significant differences in the retention of elements in rats fed diets derived from different cultivation systems were seen, since higher intake resulted in correspondingly higher excretion. CONCLUSION: This study does not support the belief that organically grown foodstuffs generally contain more major and trace elements than conventionally grown foodstuffs, nor does there appear to be an effect on the bioavailability of major and trace minerals in rats. Copyright © 2008 Society of Chemical Industry 相似文献