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排序方式: 共有1053条查询结果,搜索用时 31 毫秒
71.
72.
Magalhaes KD Costa LS Fidelis GP Oliveira RM Nobre LT Dantas-Santos N Camara RB Albuquerque IR Cordeiro SL Sabry DA Costa MS Alves LG Rocha HA 《International journal of molecular sciences》2011,12(5):3352-3365
In the present study, six families of sulfated polysaccharides were obtained from seaweed Dictyopteris delicatula by proteolytic digestion, followed by acetone fractionation and molecular sieving on Sephadex G-100. Chemical analyses demonstrated that all polysaccharides contain heterofucans composed mainly of fucose, xylose, glucose, galactose, uronic acid, and sulfate. The fucans F0.5v and F0.7v at 1.0 mg/mL showed high ferric chelating activity (~45%), whereas fucans F1.3v (0.5 mg/mL) showed considerable reducing power, about 53.2% of the activity of vitamin C. The fucan F1.5v presented the most prominent anticoagulant activity. The best antiproliferative activity was found with fucans F1.3v and F0.7v. However, F1.3v activity was much higher than F0.7v inhibiting almost 100% of HeLa cell proliferation. These fucans have been selected for further studies on structural characterization as well as in vivo experiments, which are already in progress. 相似文献
73.
Hoeckner Berthold; Wyatt Emma W.; Decety Jean; Nusbaum Howard 《Canadian Metallurgical Quarterly》2011,5(2):146
Film music has powerful aesthetic effects on the perception and understanding of screen content, but does it also influence viewers' sense of connection with movie characters thereby creating antecedents for an experience of empathy? Participants viewed clips showing characters' neutral or ambiguous reaction to an event, person, or object. Viewers rated character likability and their certainty about characters' thoughts in three conditions: thriller music, melodrama music, and no music. The effect of music conditions differed significantly from the no music condition. Compared to melodramatic music, thriller music significantly lowered likability and certainty about characters' thoughts. During subsequent cued recall of screen content, thriller music increased anger attributions and lowered sadness attributions, while melodramatic music increased love attributions and lowered fear attributions. The study provides evidence that film music can influence character likability and the certainty of knowing the character's thoughts, which are antecedents of empathetic concern and emphatic accuracy. Thus film music may be regarded as modulating antecedents of empathic concern and empathic accuracy. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
74.
Emma Lesson Martin Stanisstreet Edward Boyes 《The International journal of environmental studies》2013,70(1-4):89-103
The ideas of children about the environmental impact of vehicle emissions have been explored using a precoded questionnaire. The children were from British National Curriculum Years 7 (age 11/12 years), 9 (age 13/14) and 11 (age 15/16). Even in the oldest group only about half of the children appreciated the advantages of smaller, well‐maintained cars; this could have practical implication if not corrected in the adult population. Children seemed well aware of the environmental problems, smog, Acid Rain and Global Warming, to which vehicle emissions contribute, but these are part of an over‐generalised model which children employ in which cars are envisaged as contributing to other problems such as Ozone Layer depletion. We suggest that the use of the generic term ‘pollution’ to describe a wide range of environmental insults and the use of the word ‘environment’ in a non‐defined way might hinder children's differentiation of the different causes of separate environmental problems. The gaps in children's knowledge of the different components of vehicle emissions may reflect and exacerbate this difficulty. Ironically, children have a regard for the environmental and an interest in cars, and a combination of these enthusiasms may provide an opportunity for environmental education and curriculum science teaching. 相似文献
75.
Reports an error in "Does Barbie make girls want to be thin? The effect of experimental exposure to images of dolls on the body image of 5- to 8-year-old girls" by Helga Dittmar, Emma Halliwell and Suzanne Ive (Developmental Psychology, 2006 Mar, Vol 42[2], 283-292). A substantive error occurs in the Body shape dissatisfaction section on page 287. The sentence describing the calculation of body shape dissatisfaction scores from girls' responses to the Child Figure Rating Scale should instead read as follows: "A body shape dissatisfaction score was computed by subtracting the girl's actual from her ideal body size." (The following abstract of the original article appeared in record 2006-03514-007.) The ubiquitous Barbie doll was examined in the present study as a possible cause for young girls' body dissatisfaction. A total of 162 girls, from age 5 to age 8, were exposed to images of either Barbie dolls, Emme dolls (U.S. size 16), or no dolls (baseline control) and then completed assessments of body image. Girls exposed to Barbie reported lower body esteem and greater desire for a thinner body shape than girls in the other exposure conditions. However, this immediate negative impact of Barbie doll was no longer evident in the oldest girls. These findings imply that, even if dolls cease to function as aspirational role models for older girls, early exposure to dolls epitomizing an unrealistically thin body ideal may damage girls' body image, which would contribute to an increased risk of disordered eating and weight cycling. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
76.
In this paper, the diagnosability of n-dimensional star graph Sn under the comparison diagnosis model has been studied. It is proved that Sn is (n−1)-diagnosable under the comparison diagnosis model when n?4. 相似文献
77.
Marcos Barreto de Mendonca Maurício Ehrlich 《Canadian Metallurgical Quarterly》2006,132(10):1284-1292
This paper presents a study of ochre formation in geotextile filters. Ochre is a substance found sticking to solid surfaces of drainage systems that may cause clogging. The accumulation of such materials in a drainage system may have undesirable implications, such as a decrease in drainage flow capacity and an increase in soil pore pressure; instability of soil masses and retaining systems; and alteration of the direction of flow and development of pipes. Ochre formation is the result of microbial activities on iron compounds naturally found in seepage water. Even though geotextiles have been widely used in drainage systems, very few studies have considered ochre formation in the tests. Laboratory column filter tests were conducted to simulate the ochre formation process under similar conditions to those in geotechnical works and to assess the long-term performance of a geotextile. Ochre is most likely to be formed at an aerated/nonaerated interface in the filter. In order to obtain this condition, the underneath face of the filters was opened to the atmosphere. Three different types of geotextile—nonwoven polyester, nonwoven polypropylene, and woven polypropylene—were used in the tests. Control tests were also conducted with a sand filter to provide a basis for comparison. Hydraulic conductivity changes and iron retention within the permeameters were monitored throughout the tests. Ochre was formed under the presence of iron ions and iron bacteria. During the test period, the filters were not clogged to such an extent as to induce a global reduction in the permeability of the drainage system. Nevertheless, at the end of the tests a considerable amount of ochre was found in all filters and there was a significant variation in the permeability of the geotextile filters when tested in isolation. These studies may contribute to discovering whether ochre can be considered as a biofilm, evaluating the clogging potential and defining mitigating measures. 相似文献
78.
79.
This article presents an elaborated model of organizational regression suggesting that, within the framework of general systems and catastrophe theory, organizational units and whole enterprises can be viewed as struggling to attain a state of super-resilience that enables them to cope effectively with a large number of regressive forces. The model comprises 6 phases of organizational regression that occur either in a 10-stage process or in a chaotically unpredictable but behaviorally understandable and orderly sequence. Internal and external regressive forces that constantly pressure an organization toward less effective performance and more primitive behavior are identified. Organizational barriers and balancing forces that counter the regressive pressures are also described, along with the consequences of regression for individuals and enterprises. Several brief case illustrations (e.g., Montgomery Ward, Apple Computer, and General Electric Corporation) are provided to highlight aspects of this conceptual approach. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
80.
In a study of pigs slaughtered at British abattoirs, approximately 23% carried Salmonella in their cecal (large intestine) contents. The most frequent serotype was Salmonella Typhimurium (STM), which was the second most common cause of human salmonellosis in Great Britain. A pig industry-monitoring program was developed to reduce Salmonella infection on British farms. The control of STM infection on the farm requires an understanding of STM transmission dynamics within the herd, and a mathematical model has been developed for an infected grower-finisher farm. The model estimates the probability of a random pig being infected with STM. There are three broad categories of STM infection in pigs: pigs that are infected but unable to transmit the infection (latent); pigs that are infectious, i.e., able to transmit the infection (shedders); and pigs that have stopped shedding but harbor STM in their internal organs (carriers). The model estimates that 21.0% (5th and 95th percentiles, 0.05 to 77.5%) of slaughter-age pigs on an infected farm are likely to be shedding STM. Although this range is wide, it is biologically plausible. Sensitivity analysis of the total number of infected pigs revealed that the most significant input parameters are the probability of effective contact between a specific infectious and susceptible pig and the duration of shedding. The model predicted that 11.5% of pigs would be shedding STM at slaughter age. This value is close to the estimate obtained from a British abattoir survey that 11. 1% of pigs carried STM in their ceca, indicating that the model has reasonable validity. 相似文献