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  • SAGE Publications  (3)
  • 1
    Online Resource
    Online Resource
    SAGE Publications ; 2013
    In:  Acta Radiologica Vol. 54, No. 8 ( 2013-10), p. 909-915
    In: Acta Radiologica, SAGE Publications, Vol. 54, No. 8 ( 2013-10), p. 909-915
    Abstract: The low-dose computed tomography (CT) technique has been widely used because it decreases the potential risk of radiation exposure, as well as enabling low-dose CT-guided lung lesion biopsy. However, uncertainties remain regarding diagnostic accuracy, radiation dose, complication rate, and image quality. Purpose To compare the diagnostic accuracy, radiation dose, complication rate, and image quality of lung lesion biopsy between conventional CT-guided and low-dose CT-guided techniques. Material and Methods A total of 90 patients were prospectively enrolled and randomized into two groups (group A: 120 kv; 200 mA; thickness, 2.0 mm; pitch, 16 mm/rot; n = 44; group B: 120 kv;10 mA; thickness, 2.0 mm; pitch, 23 mm/rot; n = 46). Sensitivity, specificity, accuracy, positive predictive value (PPV), negative predictive value (NPV), radiation dose, image quality, and complication rate were compared. All variables between the two groups were analyzed using chi-square and Student's t tests. A P value of 〈 0.05 was considered statistically significant. Results The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) for diagnosing lung lesions were 96.88%, 100%, 97.5%, 100%, and 88.89% in group A, respectively. In group B, the values were 96.67%, 100%, 97.5%, 100%, and 90.91%, respectively ( P 〉 0.05). The mean weighted CT dose index (CTDIw) and dose-length product (DLP) were 29.29 ± 3.93 mGy and 211.74 ± 37.89 mGy*cm in group A and 1.55 ± 0.15 mGy and 10.98 ± 1.56 mGy*cm in group B ( P 〈 0.001). Image quality satisfied the need for a coaxial biopsy. Complications in group A and group B were observed in 27.28% and 23.91% of the patients, respectively ( P 〉 0.05). Conclusion Compared to conventional CT-guided biopsies, lung lesion biopsies guided by the low-dose CT biopsy protocol showed dramatically lower CTDIw and DLP levels. In contrast, the diagnostic yield of the procedures did not differ significantly, which is a recommended technique in certain populations.
    Type of Medium: Online Resource
    ISSN: 0284-1851 , 1600-0455
    RVK:
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2013
    detail.hit.zdb_id: 2024579-8
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  • 2
    Online Resource
    Online Resource
    SAGE Publications ; 2023
    In:  Journal of Industrial Textiles Vol. 53 ( 2023-01), p. 152808372311717-
    In: Journal of Industrial Textiles, SAGE Publications, Vol. 53 ( 2023-01), p. 152808372311717-
    Abstract: Two-scale modeling is adopted to investigate the thermo-mechanical behavior of 3D four-directional (3D4D), 3D five-directional (3D5D), and 3D full five-directional (3DF5D) braided composites. Based on the stress-strain relationship considering thermal expansion and the periodic boundary conditions, the elastic constants and the coefficients of thermal expansion (CTE) of the three types of braided composites are predicted by a two-scale homogenization method. The micro stress under free expansion and thermo-mechanical coupling is also simulated. The calculated results are in good agreement with experimental results from relevant references. The numerical results show that the longitudinal elastic and thermal expansion properties are gradually improved with the increase of axial yarn content from 3D4D to 3D5D and then to 3DF5D braided composites. The braiding angle corresponding to the zero longitudinal CTE of each braided structure is basically about 40°. Furthermore, with the increase of temperature, the longitudinal micro-stress in yarns increases gradually, but that in matrix drops. These conclusions will provide a reliable basis for the structural optimization design and safety evaluation of 3D multi-directional braided composites in a thermal environment.
    Type of Medium: Online Resource
    ISSN: 1528-0837 , 1530-8057
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2023
    detail.hit.zdb_id: 2095351-3
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  • 3
    Online Resource
    Online Resource
    SAGE Publications ; 2010
    In:  Transportation Research Record: Journal of the Transportation Research Board Vol. 2181, No. 1 ( 2010-01), p. 11-18
    In: Transportation Research Record: Journal of the Transportation Research Board, SAGE Publications, Vol. 2181, No. 1 ( 2010-01), p. 11-18
    Abstract: A fatigue crack propagation model of asphalt mixtures is developed on the basis of viscoelasticity and fracture mechanics. The fatigue model is extended from the generalized J-integral model proposed previously by the authors to consider the effects of temperature and air void. Laboratory fatigue crack propagation tests for three different asphalt mixtures are performed at various loading conditions, air voids, and temperatures. The test results indicate that the J-integral could take care of the loading magnitude and frequency dependence of the crack speed but could not consider temperature dependence completely. The air void and temperature effects on crack propagation in asphalt mixtures are investigated. Generally the crack propagation of the asphalt mixtures is developed more quickly at high temperatures and large air voids. Finally, the generalized J-integral model is extended by employing a regression function to take care of the temperature and air void effects. The resulting model could provide a reasonable prediction of fatigue crack propagation lives of the asphalt mixtures under various loading and temperature conditions.
    Type of Medium: Online Resource
    ISSN: 0361-1981 , 2169-4052
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2010
    detail.hit.zdb_id: 2403378-9
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