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排序方式: 共有493条查询结果,搜索用时 18 毫秒
351.
FL Bayer 《Canadian Metallurgical Quarterly》1997,14(6-7):661-670
Recycled plastics have been used in food-contact applications since 1990 in various countries around the world. To date, there have been no reported issues concerning health or off-taste resulting from the use of recycled plastics in food-contact applications. This is due to the fact that the criteria that have been established regarding safety and processing are based on extremely high standards that render the finished recycled material equivalent in virtually all aspects to virgin polymers. The basis for this conclusion is detailed in this document. 相似文献
352.
MS De Bodt FL Wuyts PH Van de Heyning L Lambrechts D Vanden Abeele 《Canadian Metallurgical Quarterly》1998,108(9):1363-1367
OBJECTIVES: Investigate whether vocal problems in future professional activities can be predicted by early laryngeal and phoniatric evaluation and whether a vocal endurance test can contribute to this evaluation. STUDY DESIGN: Five-year follow-up study of 30 female education majors, initially documented with a standard voice assessment and a vocal endurance test. Measurements before and after vocal endurance testing were compared and related to the vocal outcome 5 years after the initial testing. METHODS: Voice assessment included perceptual evaluation, airflow measurements, Fo and SPL measurements, voice range profile and laryngeal (stroboscopic) examination. The Standard Tolerance Test, as recommended by the Union of European Phoniatricians, was followed. This data set was completed with a questionnaire concerning the subjects' vocal behavior. This questionnaire was repeated 5 years later. RESULTS: No significant differences were found for ENT scores (laryngostroboscopy) (P = .018). Logistic regression was used to determine a relationship between initial observations and the final outcome. CONCLUSIONS: The role of an endurance test as used in this study is negligible for the prediction of vocal outcome. A combination of laryngeal examination, maximum phonation time, and perceptual evaluation, assessed prior to the endurance test, reveals a prediction of the vocal outcome with a specificity of 90% and a sensitivity of 70%. 相似文献
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FL Cavender WH Steinhagen CE Ulrich WM Busey BY Cockrell JK Haseman MD Hogan RT Drew 《Canadian Metallurgical Quarterly》1977,3(3):521-533
Ozone and the oxides of sulfur are common environmental pollutants. The acute pulmonary lesions caused by ozone and sulfuric acid mist in rats and guinea pigs have been characterized. Rats are not affected by sulfuric acid mist in concentrations up to 100 mg/m3 except for reduced body weight at the higher doses. A true alveolitis develops in guinea pigs exposed to more than 20 mg/m3 sulfuric acid mist. The ozone lesion is primarily confined to the terminal bronchioles and proximal alveoli. In combination studies with up to 2 ppm ozone and up to 10 mg/m3 sulfuric acid mist, the pulmonary lesion and lung/body weight data were essentially the same as in exposure to ozone alone, and the number of statistically significant synergistic effects in rats and guinea pigs was about what one would expect to observe by chance alone. 相似文献
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FL Moreno T Villanueva LA Karagounis JL Anderson 《Canadian Metallurgical Quarterly》1994,90(1):94-100
BACKGROUND: QT dispersion (QTd, equals maximal minus minimal QT interval) on a standard ECG has been shown to reflect regional variations in ventricular repolarization and is significantly greater in patients with than in those without arrhythmic events. METHODS AND RESULTS: To assess the effect of thrombolytic therapy on QTd, we studied 244 patients (196 men; mean age, 57 +/- 10 years) with acute myocardial infarction (AMI) who were treated with streptokinase (n = 115) or anistreplase (n = 129) at an average of 2.6 hours after symptom onset. Angiograms at 2.4 +/- 1 hours after thrombolytic therapy showed reperfusion (TIMI grade > or = 2) in 75% of patients. QT was measured in 10 +/- 2 leads at 9 +/- 5 days after AMI by using a computerized analysis program interfaced with a digitizer. QTd, QRSd, JT (QT minus QRS), and JT dispersion (JTd, equals maximal minus minimal JT interval) were calculated with a computer. There were significant differences in QTd (96 +/- 31, 88 +/- 25, 60 +/- 22, and 52 +/- 19 milliseconds; P < or = .0001) and in JTd (97 +/- 32, 88 +/- 31, 63 +/- 23, and 58 +/- 21 milliseconds; P = .0001) but not in QRSd (25 +/- 10, 22 +/- 7, 28 +/- 9, and 24 +/- 9 milliseconds; P = .24) among perfusion grades 0, 1, 2, and 3, respectively. Similar results were obtained comparing TIMI grades 0/1 with 2/3 and 0/1/2 with 3. Patients with left anterior descending (versus right and left circumflex) coronary artery occlusion showed significantly greater QTd (70 +/- 29 versus 59 +/- 27 milliseconds, P = .003) and JTd (74 +/- 30 versus 63 +/- 27 milliseconds, P = .004). Similarly, patients with anterior (versus inferior/lateral) AMI showed significantly greater QTd (69 +/- 30 versus 59 +/- 27 milliseconds, P = .006) and JTd (73 +/- 30 versus 63 +/- 27 milliseconds, P = .007). Results did not change when Bazett's QTc or JTc was substituted for QT or JT or when ANOVA included adjustments for age, sex, drug assignment, infarct site, infarct vessel, and number of measurable leads. On ANCOVA, the relation of QTd or JTd and perfusion grade was not influenced by heart rate. CONCLUSIONS: Successful thrombolysis is associated with less QTd and JTd in post-AMI patients. The results are equally significant when either QT or JT is used for analysis. These data support the hypothesis that QTd after AMI depends on reperfusion status as well as infarct site and size. Reduction in QTd and its corresponding risk of ventricular arrhythmia may be mechanisms of benefit of thrombolytic therapy. 相似文献
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