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Visual Method (visual + method)
Selected AbstractsRight Ventricular Function Assessment: Comparison of Geometric and Visual Method to Short-Axis Slice Summation MethodECHOCARDIOGRAPHY, Issue 10 2007Daniel Drake M.D. Background: Short-axis summation (SAS) method applied for right ventricular (RV) volumes and right ventricular ejection fraction (RVEF) measurement with cardiac MRI is time consuming and cumbersome to use. A simplified RVEF measurement is desirable. We compare two such methods, a simplified ellipsoid geometric method (GM) and visual estimate, to the SAS method to determine their accuracy and reproducibility. Methods: Forty patients undergoing cine cardiac MRI scan were enrolled. The images acquired were analyzed by the SAS method, the GM (area and length measurement from two orthogonal planes) and visual estimate. RVEF was calculated using all three methods and RV volumes using the SAS and GM. Bland,Altman analysis was applied to test the agreement between the various measurements. Results: Mean RVEF was 49 ± 12% measured by SAS method, 54 ± 12% by the GM, and 49 ± 11% by visual estimate. There were similar bias and limits of agreement between the visual estimate and the GM compared to SAS. The interobserver variability showed a bias close to zero with limits of agreement within ±10% absolute increments of RVEF in 35 of the patients. The RV end-diastolic volume by GM showed wider limits of agreement. The RV end-systolic volume by GM was underestimated by around 10 ml compared to SAS. Conclusion: Both the visual estimate and the GM had similar bias and limits of agreement when compared to SAS. Though the end-systolic measurement is somewhat underestimated, the geometric method may be useful for serial volume measurements. [source] A simple mounting model for consistent determination of the accuracy and repeatability of apex locatorsINTERNATIONAL ENDODONTIC JOURNAL, Issue 2 2006A. ElAyouti Abstract Aim, To develop a precise and simple mounting model (MM) for evaluating apex locators and to compare the repeatability of the MM with a conventional visual method (VM). Methodology, Electronic working length determination was performed in 32 maxillary central incisors using two methods: (i) the MM method and (ii) a conventional VM. The MM utilizes a micrometer to determine the distance travelled by the measuring file during working length determination. In the VM, the length of the measuring file (representing the working length) is determined visually using a caliper and a microscope at 6× magnification. Each measurement was repeated once. The repeatability of each method was evaluated by calculating the coefficient of repeatability. Results, The coefficient of repeatability, which includes 95% of the differences between repeated measurements, was 0.04 mm for MM compared with 0.9 mm for VM. The measurement error of MM was significantly lower than VM (0.02 and 0.4 mm respectively). There was a statistically significant difference between the means of absolute difference in repeated measurements: MM 0.01 mm (95% confidence interval (CI): 0.01; 0.02 mm) compared with VM 0.4 mm (95% CI: 0.3; 0.5 mm). Conclusion, The new MM had superior repeatability in comparison with the conventional method where visual interpretation is a source of inaccurate measurement. [source] Resolution of structure characteristics of AE signals in multiphase flow system,From data to informationAICHE JOURNAL, Issue 10 2009Yi-Jun He Abstract This investigation was performed to study the underlying structure characteristics of acoustic emission (AE) signals, which could be helpful not only to understand a relatively complete picture of hydrodynamics in multiphase flow systems, but also to extract the most useful information from the original signals with respect to a particular measurement requirement. However, due to AE signals are made up of emission from many acoustic sources at different scales, the resolution of AE signals is often very complicated and appears to be relatively poorly researched. In this study, the structure characteristics of AE signals measured both in gas,solid fluidized bed and liquid,solid stirred tank were researched in detail by resorting to wavelet transform and rescaled range analysis. A general criterion was proposed to resolve AE signals into three physical-related characteristic scales, i.e., microscale, mesoscale, and macroscale. Multiscale resolution of AE signals implied that AE signals in microscale represented totally the dynamics of solid phase and could be applied to measure particle-related properties. Furthermore, based on the structure characteristics of AE signals, useful features related to particles motion were extracted to establish two new prediction models, one for on-line measurements of particle size distribution (PSD) and average particle size in gas,solid fluidized bed and the other for on-line measurement of the suspension height in liquid,solid stirred tank. The prediction results indicated that (1) measurements of PSD and average particle size using AE method showed a fairly good agreement with that using sieve method both for laboratory scale and plant scale fluidized beds, and (2) measurements of the suspension height using AE method showed a fairly good agreement with that using visual method. The results thus validated that the extracted features based on analyses of structure characteristics of AE signals were very useful for establishing effective on-line measurement models with respect to some particular applications. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Direct analysis of single leaf disks for chemopreventive glucosinolatesPHYTOCHEMICAL ANALYSIS, Issue 3 2002Qiaomei Wang Abstract Natural isothiocyanates, produced during plant tissue damage from methionine-derived glucosinolates, are potent inducers of mammalian phase 2 detoxification enzymes such as quinone reductase (QR). A greatly simplified bioassay for glucosinolates based on induction and colorimetric detection of QR activity in murine hepatoma cells is described. It is demonstrated that excised leaf disks of Arabidopsis thaliana (ecotype Columbia) can directly and reproducibly substitute for cell-free leaf extracts as inducers of murine QR, which reduces sample preparation to a minimum and maximizes throughput. A comparison of 1 and 3,mm diameter leaf disks indicated that QR inducer potency was proportional to disk circumference (extent of tissue damage) rather than to area. When compared to the QR inducer potency of the corresponding amount of extract, 1,mm leaf disks were equally effective, whereas 3,mm disks were 70% as potent. The QR inducer potency of leaf disks correlated positively with the content of methionine-derived glucosinolates, as shown by the analysis of wild-type plants and mutant lines with lower or higher glucosinolate content. Thus, the microtitre plate-based assay of single leaf disks provides a robust and inexpensive visual method for rapidly screening large numbers of plants in mapping populations or mutant collections and may be applicable to other glucosinolate-producing species. Copyright © 2002 John Wiley & Sons, Ltd. [source] Enthesopathies as occupational stress markers: Evidence from the upper limbAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2010Sébastien Villotte Abstract Enthesopathies,that is, "musculo-skeletal stress markers",are frequently used to reconstruct past lifestyles and activity patterns. Relatively little attention has been paid in physical anthropology to methodological gaps implicit in this approach: almost all methods previously employed neglect current medical insights into enthesopathies and the distinction between healthy and pathological aspects has been arbitrary. This study presents a new visual method of studying fibrocartilaginous enthesopathies of the upper limb (modified from Villotte: Bull Mém Soc Anthropol Paris n.s. 18 (2006) 65,85), and application of this method to 367 males who died between the 18th and 20th centuries, from four European identified skeletal collections: the Christ Church Spitalfields Collection, the identified skeletal collection of the anthropological museum of the University of Coimbra, and the Sassari and Bologna collections of the museum of Anthropology, University of Bologna. The analysis, using generalized estimating equations to model repeated binary outcome variables, has established a strong link between enthesopathies and physical activity: men with occupations involving heavy manual tasks have significantly (P -value < 0.001) more lesions of the upper limbs than nonmanual and light manual workers. Probability of the presence of an enthesopathy also increases with age and is higher for the right side compared with the left. Our study failed to distinguish significant differences between the collections when adjusted for the other effects. It appears that enthesopathies can be used to reconstruct past lifestyles of populations if physical anthropologists: 1) pay attention to the choice of entheses in their studies and 2) use appropriate methods. Am J Phys Anthropol, 2010. © 2009 Wiley-Liss, Inc. [source] | |||||||||||||