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Three-dimensional Analysis (three-dimensional + analysis)
Selected AbstractsConfocal microscopy of the light organ crypts in juvenile Euprymna scolopes reveals their morphological complexity and dynamic function in symbiosisJOURNAL OF MORPHOLOGY, Issue 5 2006Laura K. Sycuro Abstract In the hours to days following hatching, the Hawaiian bobtail squid, Euprymna scolopes, obtains its light-emitting symbiont, Vibrio fischeri, from the surrounding environment and propagates the bacteria in the epithelial crypts of a specialized light organ. Three-dimensional analyses using confocal microscopy revealed that each of the three crypts on either side of the juvenile light organ is composed of four morphological regions. Progressing from the lateral pore to the medial blind end of each crypt, the regions consist of 1) a duct, 2) an antechamber, 3) a bottleneck, and 4) a deep region. Only the deep region houses a persistent bacterial population, whereas the duct, antechamber, and bottleneck serve as conduits through which the bacteria enter during initial colonization and exit during diel venting, a behavior in which ,90% of the symbionts are expelled each dawn. Our data suggest that, like the duct, the antechamber and bottleneck may function to promote and maintain the specificity of the symbiosis. Pronounced structural and functional differences among the deep regions of the three crypts, along with previously reported characterizations of embryogenesis, suggest a continued developmental progression in the first few days after hatching. Taken together, the results of this study reveal a high degree of complexity in the morphology of the crypts, as well as in the extent to which the three crypts and their constituent regions differ in function during the early stages of the symbiosis. J. Morphol. © 2006 Wiley-Liss, Inc. [source] Alterations of intraretinal layers in acute central serous chorioretinopathyACTA OPHTHALMOLOGICA, Issue 5 2009Christian Ahlers Abstract. Purpose:, Optical coherence tomography (OCT) is restricted by its low scanning speed and limited resolution. High-definition raster-scanning OCT (HD-OCT) was used to evaluate changes in retinal microstructure in patients with acute central serous chorioretinopathy (CSCR) and to find new morphological features. Methods:, Eighteen patients with subretinal fluid accumulation caused by acute CSCR were imaged in a cross-sectional study design. High-speed frequency-domain HD-OCT was used to image an area of 6 × 6 mm in the macular retina. Three-dimensional analyses were performed using en-face imaging and section analysis of single HD-OCT scans. Results:, Detailed information about fluid accumulation can be obtained in all compartments. Discrete changes in reflectivity are visualized within the outer nuclear or plexiform layers in > 90% of patients. Subretinal fluid appears as a dome-shaped pool of fluid and is not associated with a loss of photoreceptor layer integrity. Deposits are demarcated beneath the outer cone segments. Multiple small pigment epithelial detachments are present in > 60% of patients. Conclusions:, High-definition OCT provides extensive information regarding precise topographic and layer-specific localization of discrete morphological changes. Along with well-known changes in the retinal microstructure, hyper-reflectivity can be imaged in the outer nuclear or plexiform layers and may represent intraretinal changes indicating the presence of subretinal pathologies or retinal maladjustment caused by the underlying pathology. [source] Three-dimensional analysis of a driver-passenger vehicle interfaceHUMAN FACTORS AND ERGONOMICS IN MANUFACTURING & SERVICE INDUSTRIES, Issue 3 2004Sung-Jae Chung This article presents a method of analyzing how drivers' anthropometric data are best accommodated by a specific driver-vehicle interface. Three-dimensional (3-D) manikins with 18 links were developed using anthropometric data for the U.S. 95th percentile male and 5th percentile female. In addition, an adjustable seating buck was constructed to control 7 package variables. After the manikins were positioned in each driving environment, 3-D Cartesian coordinates for the manikins' articulations were determined using a coordinate measuring machine. The data were then converted into joint angles to suggest suitable driving environments that consider appropriate driving postures. © 2004 Wiley Periodicals, Inc. Hum Factors Man 14: 269,284, 2004. [source] Three-dimensional analysis of single pile response to lateral soil movementsINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 8 2002J. L. Pan Abstract Three-dimensional finite element analysis was carried out to investigate the behaviour of single piles subjected to lateral soil movements and to determine the ultimate soil pressures acting along the pile shaft. The finite element analysis program ABAQUS was used for the analysis and run on a SUN Workstation. The von Mises constitutive model was employed to model the non-linear stress,strain soil behaviour. The pile was assumed to have linear elastic behaviour. This was considered to be a reasonable approximation, as the maximum stress developed in the pile did not exceed the yield stress of the concrete pile. The length of the pile is 15 m, the width of the square pile is 1 m. The three-dimensional finite element mesh used in the analysis was optimized taking into account the computing capacity limitations of the Sun Workstation. The computed ultimate soil pressures agreed well with those from the literature. The shapes of the soil pressure versus soil movement curves and the soil pressure versus the relative soil,pile displacement curves as well as the magnitude of the relative soil,pile displacement to mobilize the ultimate soil pressures were in reasonable agreement with those reported by other researchers. Copyright © 2002 John Wiley & Sons, Ltd. [source] Three-dimensional analysis of intermediate filament networks using SEM tomographyJOURNAL OF MICROSCOPY, Issue 1 2010S. LÜCK Summary We identified tomographic reconstruction of a scanning electron microscopy tilt series recording the secondary electron signal as a well-suited method to generate high-contrast three-dimensional data of intermediate filament (IF) networks in pancreatic cancer cells. Although the tilt series does not strictly conform to the projection requirement of tomographic reconstruction, this approach is possible due to specific properties of the detergent-extracted samples. We introduce an algorithm to extract the graph structure of the IF networks from the tomograms based on image analysis tools. This allows a high-resolution analysis of network morphology, which is known to control the mechanical response of the cells to large-scale deformations. Statistical analysis of the extracted network graphs is used to investigate principles of structural network organization which can be linked to the regulation of cell elasticity. [source] Cyclic fatigue resistance and three-dimensional analysis of instruments from two nickel,titanium rotary systemsINTERNATIONAL ENDODONTIC JOURNAL, Issue 10 2006N. M. Grande Abstract Aim, To determine how instrument design affects the fatigue life of two nickel,titanium (Ni,Ti) rotary systems (Mtwo and ProTaper) under cyclic fatigue stress in simulated root canals. Methodology, Cyclic fatigue testing of instruments was performed in stainless steel artificial canals with radii of curvature of 2 or 5 mm and an angle of curvature of 60°. A total of 260 instruments were rotated until fracture occurred and the number of cycles to failure were recorded. The morphology of Ni,Ti rotary instruments was investigated by measuring the volume of millimetre slices of each instrument size starting from the tip to the shank by means of ,CT analysis. The fracture surface of three representative samples of each size was analysed by scanning electron microscopy (SEM). Data were analysed by one-way anova, Holm t -test, paired t -test and linear regression; the significance was determined at the 95% confidence level. Results, Cycles to failure significantly decreased as the instrument volume increased for both the radii of curvature tested (P < 0.01). The radius of curvature had a statistically significant influence on the fatigue life of the instruments (P < 0.05). Larger instruments underwent fracture in less time under cyclic stress than smaller ones. SEM evaluation showed typical features of fracture through fatigue failure. Conclusions, The metal volume in the point of maximum stress during a cyclic fatigue test could affect the fatigue life of Ni,Ti rotary instruments. The larger the metal volume, the lower the fatigue resistance. [source] Spatial foundation structures over no tension soilINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 14 2005A. Baratta Abstract The problem of the stress distribution induced in the soil by a single circular foundation structure is approached in a three-dimensional analysis. Since the soil is typically made by not-cohesive materials, its behaviour is modelled by means of the not resisting tension (NRT) hypothesis, thus assuming that its very low resistance to tensile stresses can be completely neglected and that it keeps linearly elastic under pure compression. After developing the problem from a theoretical point of view on the basis of an energetic approach, a numerical application,which is able to reproduce the stress distribution induced by a circular foundation on the soil,is performed. Copyright © 2005 John Wiley & Sons, Ltd. [source] Adaptive mesh technique for thermal,metallurgical numerical simulation of arc welding processesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 5 2008M. Hamide Abstract A major problem arising in finite element analysis of welding is the long computer times required for a complete three-dimensional analysis. In this study, an adaptative strategy for coupled thermometallurgical analysis of welding is proposed and applied in order to provide accurate results in a minimum computer time. The anisotropic adaptation procedure is controlled by a directional error estimator based on local interpolation error and recovery of the second derivatives of different fields involved in the finite element calculation. The methodology is applied to the simulation of a gas,tungsten-arc fusion line processed on a steel plate. The temperature field and the phase distributions during the welding process are analyzed by the FEM method showing the benefits of dynamic mesh adaptation. A significant increase in accuracy is obtained with a reduced computational effort. Copyright © 2007 John Wiley & Sons, Ltd. [source] Boundary elements for half-space problems via fundamental solutions: A three-dimensional analysisINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 11 2001J. Liang Abstract An efficient solution technique is proposed for the three-dimensional boundary element modelling of half-space problems. The proposed technique uses alternative fundamental solutions of the half-space (Mindlin's solutions for isotropic case) and full-space (Kelvin's solutions) problems. Three-dimensional infinite boundary elements are frequently employed when the stresses at the internal points are required to be evaluated. In contrast to the published works, the strongly singular line integrals are avoided in the proposed solution technique, while the discretization of infinite elements is independent of the finite boundary elements. This algorithm also leads to a better numerical accuracy while the computational time is reduced. Illustrative numerical examples for typical isotropic and transversely isotropichalf-space problems demonstrate the potential applications of the proposed formulations. Incidentally, the results of the illustrative examples also provide a parametric study for the imperfect contact problem. Copyright © 2001 John Wiley & Sons, Ltd. [source] Global and systematic demonstration for the practical usage of a direct in vivo measurement system to evaluate wrinklesINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 6 2007T. Fujimura Synopsis The global and systematic demonstration for the practical usage of a direct three-dimensional in vivo measurement system (PRIMOS) to evaluate wrinkles was investigated. Ten repetitive measurements of the corner of the eye of a subject showed that the coefficient of variation (CV)% value was 7.0% in a typical line-length roughness parameter Ra (the arithmetic mean of roughness), and that the CV% value in a typical surface area roughness parameter Sa was 2.4%. The relationships between the roughness values obtained from the corners of the eye and the age or wrinkle scores of Japanese women aged 10,70 years was examined. The values of several roughness parameters within the evaluation line length or surface area increased with age and showed a good correlation coefficient (r > 0.743). Similar relationships between the wrinkle scores and the values of roughness parameters were observed (r > 0.699). The roughness values were widely distributed even in the same wrinkle score because the measurement areas were limited and the values of skin roughness, including the microreliefs and/or small warts, were included in the calculation. However, changes in roughness values are considerable following treatment with potent active ingredients such as retinoic acid, so that this in vivo evaluation method is sufficient to objectively evaluate wrinkles. We conclude that the direct three-dimensional analysis of wrinkles in vivo should become a popular method to objectively evaluate wrinkles in clinical tests of wrinkle-smoothing ingredients or following cosmetic surgery to provide evidence of quantitative results. Résumé Une démonstration globale et systématique pour l'utilisation pratique d'un système de mesurage in vivo tridimensionnel direct (PRIMOS) pour évaluer les rides àétéétudiée. Dix mesurages répétitifs de la cornée de l',il d'un sujet ont montrées que la valeur du % du coefficient de variation était de 7,0% pour un paramètre de rugosité de mesure typique Ra (moyen arithmétique de rugosité), et que la valeur du % du coefficient de dérivation pour un paramètre de rugosité d'une surface typique Saétait de 2,4%. Les relations entre les valeurs de rugosité obtenues des cornées de l',il et l'âge ou les indices de rides de femmes japonaises âgées de 10 à 70 ans furent examinées. Les valeurs de plusieurs paramètres de rugosité en-deçà de la mesure d'évaluation ou de la surface ont augmenté avec l'âge et ont présenté un bon coefficient de corrélation (r > 0,743). Des relations similaires entre des indices de rides et les valeurs de paramètres de rugosité furent observées (r > 0,699). Les valeurs de rugosité furent largement réparties même avec un indice de rugosité semblable, du fait que les zones de mesurages furent limitées et que les valeurs de rugosité de la peau, comprenant des microreliefs et/ou de petites verrues, furent inclues dans les calculs. Cependant, des changements dans les valeurs de rugosité ont été considérables selon le traitement avec des ingrédients actifs potentiels, tel que l'acide rétinoïque, de telle sorte que cette méthode d'évaluation in vivo est suffisante pour une évaluation objective des rides. Nous en concluons qu'une analyse tridimensionnelle directe des rides in vivo est une méthode pratique pour évaluer objectivement des rides dans des essais cliniques d'ingrédients d'adoucissage des rides ou en suivant une chirurgie esthétique pour mettre en évidence des résultats quantitatifs. [source] Characterization of dilute species within CVD-grown silicon nanowires doped using trimethylboron: protected lift-out specimen preparation for atom probe tomographyJOURNAL OF MICROSCOPY, Issue 2 2010T. J. PROSA Summary Three-dimensional quantitative compositional analysis of nanowires is a challenge for standard techniques such as secondary ion mass spectrometry because of specimen size and geometry considerations; however, it is precisely the size and geometry of nanowires that makes them attractive candidates for analysis via atom probe tomography. The resulting boron composition of various trimethylboron vapour,liquid,solid grown silicon nanowires were measured both with time-of-flight secondary ion mass spectrometry and pulsed-laser atom probe tomography. Both characterization techniques yielded similar results for relative composition. Specialized specimen preparation for pulsed-laser atom probe tomography was utilized and is described in detail whereby individual silicon nanowires are first protected, then lifted out, trimmed, and finally wet etched to remove the protective layer for subsequent three-dimensional analysis. [source] A new method for three-dimensional skeleton graph analysis of porous media: application to trabecular bone microarchitectureJOURNAL OF MICROSCOPY, Issue 2 2000L. Pothuaud This paper introduces a new three-dimensional analysis of complex disordered porous media. Skeleton graph analysis is described and applied to trabecular bone images obtained by high resolution magnetic resonance imaging. This technique was developed bearing in mind topological considerations. The correspondence between vertices and branches of the skeleton graph and trabeculae is used in order to get local information on trabecular bone microarchitecture. In addition to real topological parameters, local structural information about trabeculae, such as length and volume distributions, are obtained. This method is applied to two sets of samples: six osteoporosis and six osteoarthritis bone samples. We demonstrate that skeleton graph analysis is a powerful technique to describe trabecular bone microarchitecture. [source] A three-dimensional analysis of coextrusion in a single manifold flat diePOLYMER ENGINEERING & SCIENCE, Issue 9 2000W. A. Gifford The coextrusion of two polymers through a single manifold flat die is examined. The three components of velocity and the pressure are determined in each layer along with the interface between the layers. It is shown that even when the viscosity ratio is one (i.e., single layer), flat "layers" entering the die will not remain flat but will be distorted by the die. For coextrusion of two polymers, the distortion of the interface profile at the exit of the die and thus the uniformity of the layers depends upon the viscosity and flow rate ratios of the two polymers as well as the geometry of the die. [source] A comparison of the impact of TOVS arid ATOVS satellite sounding data on the accuracy of numerical weather forecastsTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 569 2000S. J. English Abstract The Advanced TIROS Operational Vertical Sounder (ATOVS) was launched on the NOAA-15 satellite in May 1998. This provided a very significant improvement in the information available from meteorological polar-orbiting satellites compared with the previous TIROS Operational Vertical Sounder system, particularly for humidity and vertical resolution of temperature in cloudy areas. In preparation for assimilation of the observations into a three-dimensional analysis of atmospheric temperature and humidity, the observations have been compared with calculated top-of-atmosphere brightness temperatures computed from numerical weather prediction model profiles of temperature and humidity. Differences between observed and modelled brightness temperature are small. In some parts of the tropics and northern hemisphere the standard deviation of these differences for the tropospheric Advanced Microwave Sounding Unit sounding channels is only marginally higher than the radiometric noise of the observations. Early in 1999 a series of observation-system experiments were completed in which ATOVS observations were assimilated using a one-dimensional variational analysis. No use of the new humidity information could be made because of interference problems experienced by the microwave humidity sounder on ATOVS. Nonetheless, these experiments showed that the assimilation of the new temperature information provided by the radiance observations reduces forecast errors by as much as 20% in the southern hemisphere and 5% in the northern hemisphere. Further improvements have been found by assimilating more data over land. The major impact arises from the microwave channels. Whilst forward-model errors may be slightly lower for the microwave channels than the infrared channels the primary reason is the provision of sounding information in active weather systems, which are usually cloudy. [source] Three-dimensional and quantitative analysis of atherosclerotic plaque composition by automated differential echogenicityCATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 7 2007Nico Bruining PhD Abstract Objective: To validate automated and quantitative three-dimensional analysis of coronary plaque composition using intracoronary ultrasound (ICUS). Background: ICUS displays different tissue components based on their acoustic properties in 256 grey-levels. We hypothesised that computer-assisted image analysis (differential echogenicity) would permit automated quantification of several tissue components in atherosclerotic plaques. Methods and Results: Ten 40-mm-long left anterior descending specimens were excised during autopsy of which eight could be successfully imaged by ICUS. Histological sections were taken at 5 mm intervals and analyzed. Since most of the plaques were calcified and having a homogeneous appearance, one specimen with a more heterogeneous composition was further examined: at each interval of 5 mm, 15 additional sections (every 100 ,m) were evaluated. Plaques were scored for echogenicity against the adventitia: brighter (hyperechogenic) or less bright (hypoechogenic). Areas of hypoechogenicity correlated with the presence of smooth muscle cells. Areas of hyperechogenicity correlated with presence of collagen, and areas of hyperechogenicity with acoustic shadowing correlated with calcium. None of these comparisons showed statistical significant differences. Conclusion: This ex vivo feasibility study shows that automated three-dimensional differential echogenicity analysis of ICUS images allows identification of different tissue types within atherosclerotic plaques. This technology may play a role as an additional tool in longitudinal studies to trace possible changes in plaque composition. © 2007 Wiley-Liss, Inc. [source] | |||||||||||||