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21.
The Doppler examination of the carotid arteries in the neck was compared with the results of the examination of the supratrochlear artery and of the angiographic controls in 76 patients. The results of this study indicate that the insonation of the carotid arteries considerably improves the diagnostic possibilities offered by the examination of the supratrochlear artery alone. There are three main advantages: 1. The reliability of the Doppler examination is improved. The insonation of the carotid arteries of the 76 angiographically controlled patients including stenoses from 50% onward gave only one false-positive and one false-negative result. The percentage of correct diagnoses thereby attained was 97%. 2. The insonation of the carotid arteries permits reliable differentiation between stenoses and occlusions. This is not possible by the insonation of the supratrochlear artery alone. There was only one case in which the distinction was wrong. 3. The localization of the pathologic process was possible in all cases. These conclusions are only valid for the detection of occlusions and stenoses of more than 50%. Low degree stenoses cannot be detected by this method.  相似文献   
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The removal of certain central nervous system (CNS) tissues (part of the bovine spongiform encephalopathy risk material) from the food chain is one of the highest priority tasks associated with avoiding contamination of the human food chain with the agent of bovine spongiform encephalopathy. A recently developed real-time PCR assay and three commercially available enzyme-linked immunosorbent assays (ELISAs) for the detection of CNS tissues in minced meat and three types of heat-treated sausages were evaluated. Bovine brain was used for spiking of internal reference material, and its detectability was examined during storage times of 12 months (for frozen minced meat and liver sausage) and 24 months (for sausages treated with medium and high heat). The real-time PCR method and both ELISA kits detected 0.1% CNS tissue in frozen minced meat and 0.1 or 1% CNS tissue in heat-treated meat products. The detectability of the amplified mRNA target region with the PCR assay was similar to the detectability of antigen by the ELISAs. Because the real-time PCR method also can be used to distinguish cattle, ovine, and caprine CNS tissues from porcine CNS tissues, it seems to be suitable as a routine diagnostic test for the sensitive and specific detection of CNS tissues in meat and meat products.  相似文献   
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Vineyards are an intensive cultivation system and expose the soil to long-lasting stress. Many vineyard areas already show high degrees of soil degradation. To prevent further soil erosion, cover crops, which have various positive effects on the environment, are highly recommended. But, depending on the climatic conditions, cover crops can reduce grape yields and are sometimes more work intensive than bare soil management. In some areas cover crops are already widespread while in others bare soil is dominant. In this qualitative study, we explore the attitudes of European winegrowers towards cover crops and determine the background for differences in the adoption of greened vineyards. Thus, we conducted focus groups with winegrowers in two different regions, namely Coteaux du Layon in France and Montilla-Moriles in Spain. In this setting, the transregional differences are mainly based on the climatic conditions but also on different business structures and knowledge levels. Direct sellers seem to be more attentive to the environment and use cover crops more often than farmers which sell their grapes to cooperatives.  相似文献   
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Effect of loading rate on the fate of mercury in littoral mesocosms   总被引:1,自引:0,他引:1  
The effects of changes in atmospheric mercury (Hg) deposition on aquatic ecosystems are poorly understood. In this study, we examined the biogeochemical cycling of Hg in littoral mesocosms receiving different loading rates (7-107 microg Hg m(-2) year(-1)). We added a 202Hg-enriched preparation to differentiate the experimentally added Hg from the ambient Hg in the environment. This approach allowed us to follow the distribution and methylation of the isotopically enriched ("spike") Hg in the mesocosms. Within 3 weeks, spike Hg was distributed throughout the main environmental compartments (water, particles, periphyton, and sediments) and began to be converted to methylmercury (MeHg). Concentrations of spike total Hg and MeHg in these compartments, measured after 8 weeks, were directly proportional to loading rates. Thus, Hg(II) availability was the limiting factor for the major processes of the biogeochemical Hg cycle, including methylation. This is the first study to demonstrate a proportional response of in situ MeHg production to atmospherically relevant loading levels. On the basis of mass balances, we conclude that loading rate had no effect on the relative distribution of spike Hg among the main compartments or on the fraction of spike Hg converted to MeHg. Therefore, loading rate did not change the relative magnitude of biogeochemical pathways competing for Hg within the mesocosms. These data suggest that reductions of Hg deposition to lake surfaces would be equally effective across a broad range of deposition rates.  相似文献   
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In the European Union, carminic acid and its ammonium, calcium, potassium or sodium salts and its aluminium lakes are approved as food additive E120. In beverages obtained from the German market 4-aminocarminic acid (“acid-stable carmine”) was detected by HPLC–PDA and LC–MS/MS. Isolation of the colorant from a liquid dye preparation used for the production of a beverage sample and subsequent NMR analysis confirmed the presence of 4-aminocarminic acid. Synthesis of 15N-4-aminocarminic acid clearly demonstrated that “acid-stable carmine” is not the ammonium salt of carminic acid, which is approved as food additive in the European Union. In fact, nitrogen in “acid-stable carmine” is covalently bound. The molecular structure of carminic acid is chemically modified and 4-aminocarminic acid does not comply with the specifications laid down for E120 in Commission Regulation (EU) No 231/2012. 4-Aminocarminic acid was also detected in the red-colored glaze of a raspberry cake and in the liquid dye preparation used for coloring this glaze.  相似文献   
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The low-energy-house laboratories at the Building Research Station incorporate various techniques for reducing energy consumption for space and water heating. They have been built to high standards of insulation, but the main experimental features concern the eight heat pumps. most of which have been purpose designed for their particular applications. In this paper the houses and their heating systems are described briefly and. whilst these are only experiments, it is expected that some may indicate cost-effective ways in which heat pumps may be employed in both new and existing construction in the future.  相似文献   
30.
Damage evolution of the alloy IN 738 LC at high temperature low cycle fatigue Herrn Professor K.-T. Rie zum 60. Geburtstag Interrupted Low-Cycle-Fatigue tests have been carried out with IN 738 LC at 850°C. The specimens were extensively examined by SEM to quantify the evolution of fatigue damage. Surface crack nucleation at oxidized grain boundaries occured during the whole experiments. The coalescence of cracks was the dominant mechanism which lead to macro crack evolution and the final fracture.  相似文献   
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