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排序方式: 共有1953条查询结果,搜索用时 15 毫秒
1.
Qin‐Tao Liu Malcolm R Clench Judith L Kinderlerer 《Journal of the science of food and agriculture》2002,82(5):553-558
Structural isomers of monoacylglycerols (monoglycerides, MAGs) were identified and compared after degradation of butter oil by two strains of Penicillium roquefortii and a commercial lipase from P roquefortii (EC 3.1.1.3) at pH 7.0 and 10 °C. The conditions were selected as they were comparable with those used in the manufacture of blue mould‐ripened cheese. The commercial lipase was selected to compare with the fungal strains in terms of acyl migration. Results showed that the main isomers formed by lipolysis with the commercial lipase were sn‐2 MAGs (64 mol%), whilst spores and emerging mycelia of P roquefortii produced mainly sn‐1(3) MAGs (83–90 mol%). The work reported here may lead to further assessment of different MAG structural isomers as natural preservatives in foods and dairy products. © 2002 Society of Chemical Industry 相似文献
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Crustacean and insect neuromuscular junctions typically include numerous small synapses, each of which usually contains one or more active zones, which possess voltage-sensitive calcium channels and are specialized for release of synaptic vesicles. Strength of transmission (the number of quantal units released per synapse by a nerve impulse) varies greatly among different endings of individual neurons, and from one neuron to another. Ultrastructural features of synapses account for some of the physiological differences at endings of individual neurons. The nerve terminals that release more neurotransmitter per impulse have a higher incidence of synapses with more than one active zone, and this is correlated with more calcium build-up during stimulation. However, comparison of synaptic structure in neurons with different physiological phenotypes indicates no major differences in structure that could account for their different levels of neurotransmitter release per impulse, and release per synapse differs among neurons despite similar calcium build-up in their terminals during stimulation. The evidence indicates differences in calcium sensitivity of the release process among neurons as an aspect of physiological specialization. 相似文献
4.
S B Watson M Charlton Y R Rao T Howell J Ridal B Brownlee C Marvin S Millard 《Water science and technology》2007,55(5):1-8
The Laurentian Great Lakes of North America are a drinking water source for millions of Canadian and US consumers. These waterbodies have undergone extensive change over the past century as a result of widespread degradation and remediation. Many of the Lakes are prone to taste and odour (T&O), and although these outbreaks have been poorly monitored, evidence suggests that they are increasing in frequency. Tracing and controlling T&O in such large systems presents a challenging task, due to their physical size and complexity. This paper presents an overview of recent investigative and management approaches to T&O in Lake Ontario and its outflow, the St. Lawrence River. We have identified three distinct patterns of T&O in these source-waters, caused by geosmin and 2-methylisoborneol and differing in their planktonic and benthic sources, and temporal and spatial dynamics. Each pattern has required a different approach by scientists and management, in partnership with the water industry. We have shown these T&O outbreaks are caused and moderated by physical, chemical and biological mechanisms over a spectrum of spatial and temporal scales. Canadian municipalities affected by these outbreaks have been key to the investigation of the links between T&O and ecosystem processes with the aim to develop more proactive water treatment and long-term management. 相似文献
5.
Collected ratings of communication ease and of engagement for 95 deaf junior and senior high school students (aged 12–21 yrs) in a large, urban, multiethnic school for the deaf. Ratings were made by the students' English teachers and by the students themselves. High teacher ratings for communication ease and engagement were associated with high academic achievement as measured by the Stanford Achievement Test. High student ratings for communication ease were also associated with academic achievement. The 2 best predictors of academic achievement were student-rated communication ease and teacher-rated engagement. Findings suggest that it is important for teachers to be sensitive to the level of communication comfort of their students because students who enjoy easier communication may be more likely to be engaged, or more actively involved, in classroom learning and to demonstrate higher academic achievement. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
6.
Comments on the assertion of K. S. Pope (see record 83-37387) that the confirmation that supposedly validates claims about the false memory syndrome, its antecedents, and its rampant magnitude needs to be made available and carefully examined. The author considers why there has been acceptance of unsubstantiated claims of false memory, and also points to essential responsibilities for psychologists whose clients have abuse memories. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
7.
Judith Wusteman 《Expert Systems》1992,9(3):139-148
Abstract: This paper describes the use of the explanation-based learning (EBL) machine learning technique in the practical domain of knowledge acquisition for expert systems. A knowledge acquisition tool, EBKAT (Explanation-Based Knowledge Acquisition Tool), is described, which may be used in the development of knowledge bases for diagnostic expert systems. The functioning of EBKAT attempts to combine the full potential of a domain expert's skills and the power of explanation-based machine learning techniques. The EBL component is not employed in the acquisition of the knowledge base rules but is used to justify the knowledge entered and to relate it to the knowledge already in the system. It is suggested that the EBKAT tool goes some way towards overcoming the knowledge acquisition bottleneck and results in the acquisition of knowledge which is rich in contextual information. 相似文献
8.
An impassioned debate over the virtues and dangers of dieting is polarizing the field and diverts attention from key issues. Dieting clearly has costs and, for some, has the potential for benefit. The primary challenges are (1) to identify individuals who will be helped or harmed by dieting, (2) to reduce the frequency and severity of dieting in those for whom the costs exceed the benefits, (3) to better understand the physiological and psychological reasons why some people can lose and others cannot, and (4) to develop safe and effective means for weight loss and its maintenance and to target these methods to individuals who stand to benefit. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
9.
Although multidisciplinary pain programs have been demonstrated to be effective, the processes of improvement have yet to be clarified. Cognitive-behavioral models posit that improvement is due, in part, to changes in patient pain beliefs and coping strategies. To test the relationships between treatment outcome and changes in beliefs and coping strategies, 94 chronic pain patients (aged 21–64 yrs) completed measures of physical and psychological functioning, health care utilization, pain beliefs, and use of pain coping strategies at admission and 3 to 6 mo after inpatient pain treatment. Improved functioning and decreased health care use were associated with changes in both beliefs and cognitive coping strategies. However, changes in some coping strategies, such as exercise and use of rest, were not associated with improvement. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
10.
Emerson Judith; Bertoch Michael R.; Checketts Keith T. 《Canadian Metallurgical Quarterly》1994,31(1):109
Explored the construct validity of transactional analysis (TA) ego state concepts. Ego states are defined as coherent systems of thoughts, feelings, and behaviors. 65 university students seeking therapy and 95 university students not receiving therapy completed the Adjective Checklist (ACL) and the Brief Symptom Inventory (BSI). Ego state scores from the ACL correlated with BSI psychological distress in predicted directions. Four of the 5 TA ego state scores differentiated Ss seeking therapy from Ss not seeking therapy. Furthermore, ego state scores changed over the course of therapy, indicating a reduction of distress. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献