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31.
Irradiation effects on meat color - a review   总被引:3,自引:0,他引:3  
Brewer S 《Meat science》2004,68(1):1-17
Color changes in irradiated fresh meat occur because of the susceptibility of the myoglobin molecule, especially the iron, to alterations in the chemical environment and to energy input. The potential for iron electrons to exist in various states makes the environment adjacent to the iron atom particularly vulnerable to the presence of electron-donating compounds and high energy inputs (irradiation). Initial condition of the myoglobin (Fe(++)O(2), Fe(+++)), modification of oxidation-reduction potential of the tissue, and generation of ligand-forming compounds (CO) from endogenous organic compounds and water are enhanced or suppressed depending on the gas atmosphere, temperature, pH and myoglobin concentration of the system. Generation of stable red pigments or brown pigments which become red over time appears to be due to binding of irradiation-generated reactive oxygen species (()O(2)(-)) or gasses (CO) which become ligands bound by iron under altered reducing conditions. Rapid generation of large amounts of metmyoglobin when irradiation is conducted in an oxygen-containing environment appears to be an acceleration of the normal process by which myoglobin undergoes oxidation. Generation of green pigments appears to be due to breakdown of the porphyrin integrity and/or formation of sulfmyoglobin. Maintenance of ideal meat color during irradiation can be enhanced by various combinations of pre-slaughter feeding of antioxidants to livestock, optimizing the condition of the meat prior to irradiation, addition of antioxidants, gas atmosphere (MAP), packaging, and temperature control.  相似文献   
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ABSTRACT: Chemical, physical, and sensory characteristics of low-fat beef patties containing carbohydrate-lipid composites (CLCs) were compared with those of all-beef patties. The CLC gels contained high-amylose cornstarch, maltodextrins, and canola oil. CLC patties had higher moisture, cooking yield, and fat retention than 20%-fat control patties. CLCs improved tenderness and juiciness and decreased cohesiveness of low-fat beef patties compared with 10%-fat control patties. Despite differences in CLC gel firmness, patties made with CLC gels containing corn, potato, and tapioca maltodextrins had similar physical and sensory properties. These results suggest that CLC gels perform well as a partial fat replacer in beef patties while providing flexibility in gel firmness selection.  相似文献   
34.
Technology has advanced to where it is possible to design and grow-with predefined geometry and surprisingly good fidelity-living networks of neurons in culture dishes. Here we overview the elements of design, emphasizing the lithographic techniques that alter the cell culture surface which in turn influences the attachment and growth of the neural networks. Advanced capability in this area makes it possible to design networks of desired complexity. Other issues addressed include the influence of glial cells and media on activity and the potential for extending the designs into three dimensions. Investigators are advancing the art and science of analyzing and controlling through stimulation the function of the neural networks, including the ability to take advantage of their geometric form in order to influence functional properties.  相似文献   
35.
Objective: To examine prospectively the relationships among psychological factors, rehabilitation adherence, and short-term rehabilitation outcome after knee surgery. Study Design and Participants: Individuals with acute anterior cruciate ligament (ACL) tears (N?=?95) completed measures of self-motivation, social support, athletic identity, and psychological distress before reconstructive surgery. After surgery, 93 participants reported on their completion of home rehabilitation exercises and cryotherapy, and their rehabilitation practitioners indicated the patients' attendance at, and adherence during, rehabilitation sessions. Rehabilitation outcome measures were taken from 69 participants approximately 6 months postsurgery. Main Outcome Measures: Knee laxity, functional ability, and subjective symptoms were the primary outcomes assessed. Results: Self-motivation was significant predictor of home exercise completion; athletic identity and psychological distress were significant predictors of knee laxity; and attendance at rehabilitation sessions and home cryotherapy completion were significant predictors of functional ability. Rehabilitation adherence did not mediate the relationship between psychological factors and rehabilitation outcome. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
36.
The image-interpretation of opium poppy crops from very high resolution satellite imagery forms part of the annual Afghanistan opium surveys conducted by the United Nations Office on Drugs and Crime and the United States Government. We tested the effect of generalization of field delineations on the final estimates of poppy cultivation using survey data from Helmand province in 2009 and an area frame sampling approach. The sample data was reinterpreted from pan-sharpened IKONOS scenes using two increasing levels of generalization consistent with observed practice. Samples were also generated from manual labelling of image segmentation and from a digital object classification. Generalization was found to bias the cultivation estimate between 6.6% and 13.9%, which is greater than the sample error for the highest level. Object classification of image-segmented samples increased the cultivation estimate by 30.2% because of systematic labelling error. Manual labelling of image-segmented samples gave a similar estimate to the original interpretation. The research demonstrates that small changes in poppy interpretation can result in systematic differences in final estimates that are not included within confidence intervals. Segmented parcels were similar to manually digitized fields and could provide increased consistency in field delineation at a reduced cost. The results are significant for Afghanistan’s opium monitoring programmes and other surveys where sample data are collected by remote sensing.  相似文献   
37.
The case for technology in developing regions   总被引:1,自引:0,他引:1  
Alongside good governance, technology is considered among the greatest enablers for improved quality of life. However, the majority of its benefits have been concentrated in industrialized nations and therefore limited to a fraction of the world's population. We believe that technology has a large role to play in developing regions, that "First World" technology to date has been a poor fit in these areas, and that there is thus a need for technology research for developing regions. Despite the relative infancy of technology studies in developing regions, anecdotal evidence suggests that access to technology has a beneficial economic impact. Cellular telephony is probably the most visible application, but there are many others, some of which we cover in this article. The World Bank's infoDev site catalogs hundreds of information and communications technologies (ICT) projects, albeit not all successful. Most of these projects use existing off-the-shelf technology designed for the industrialized world. Although it is clear that there are large differences in assumptions related to cost, power, and usage, there has been little work on how technology needs in developing regions differ from those of industrialized nations. We argue that Western market forces continue to meet the needs of developing regions accidentally at best.  相似文献   
38.
An important property of wildfire behaviour is rate of spread (ROS). The objectives of this study are to evaluate the uncertainty of landscape-scale ROS estimates derived from repetitive airborne thermal infrared (ATIR) georeferenced imagery and the utility of such estimates for understanding fire behaviour and controls on spread rates. Time-sequential ATIR image data were collected for the Cedar, Detwiler, and Rey Fires, which burned in California during summers of 2016 and 2017. We analyse error, uncertainty, and precision of ROS estimates associated with co-location accuracy, delineation of active fire front positions, and generation of fire spread vectors. The major sources of uncertainty influencing accuracy of ROS estimates are co-registration accuracy of sequential image pairs and procedures for delineating active fire front locations and spread vectors between them; none of these were found to be substantial. Median ROS estimates are 11 m min?1 for the Cedar Fire and 8 m min?1 for the Detwiler Fire, both of which burned through mixed shrub and tree areas of the Sierra Nevada foothills and were estimated for downslope spread events. Of the three study fires, the fastest spread rates (average spread of 25 m min?1 with maximum of 39 m min?1) are estimated for the Rey Fire, which burned on variable directional slopes through chaparral shrubland vegetation.  相似文献   
39.
This paper proposes a framework for generating mesh sizing functions for assembly models. Size control is crucial in obtaining a high-quality mesh with a reduced number of elements. The reduction in the number of elements will decrease computation time and memory use during mesh generation and analysis. The framework consists of a background octree lattice for storing the sizing function, a set of source entities for providing sizing information based on geometric information, and an interpolation module for calculating the sizing on the background octree lattice using the source entities. Source entities are generated by performing a detailed systematic study to identify all the geometric factors of an assembly. Disconnected skeletons are extracted and used as tools to measure 3D proximity and 2D proximity, which are two of the geometric factors. The framework facilitates the generation of a variety of meshes with a low computational cost, to meet industry needs. The framework has been tested on many industrial parts, and sizing control on a few typical assemblies has been presented to demonstrate the effectiveness of the proposed framework.  相似文献   
40.
We report measurements of supercritical heat conduction in liquid helium II at pressures above the vapor pressure. The measurements were made in glass capillary tubes of diameter 50.5 and 366.8 m in the temperature range from 1.2 to 2.1 K. As in our previous results at the vapor pressure, a clear distinction can be made between two regimes in which the average separation of vortex lines is either comparable with or larger than the size of the flow channel. In the wider tube, at high relative velocities v between the superfluid and normal component, where the vortex spacing is small, a modified form of Gorter-Mellink mutual friction F sn is observed which varies as Fsn=Asnv(v–v0)2. The coefficient A increases with pressure, and its variation with T/T(p) is in fairly good agreement with Schwarz ' microscopic theory of superfluid turbulence. However, the absolute magnitude of A is in general larger than in Schwarz ' theory and also larger than most other experimental values. In the narrower tube the measurements are all in the regime where the vortex spacing is comparable with the tube size, and they do not agree with the predictions of the Gorter-Mellink law. At present, the data cannot be analyzed quantitatively in the terms of the vortex line density, because B, the vortex line scattering coefficient, is not known at high pressures.Preparation of this paper was supported by a U.S. National Science Foundation grant DMR 7901073 and by a UK Science Research Council Senior Fellowship (DFB).SRC Senior Fellow.  相似文献   
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