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Three-dimensional
Terms modified by Three-dimensional Selected AbstractsA Three-Dimensional and Sensitive Bioassay Based on Nanostructured Quartz Combined with Viral NanoparticlesADVANCED FUNCTIONAL MATERIALS, Issue 12 2010Jong-Hwan Lee Abstract An effective mask-free method for fabricating high-aspect-ratio pillarlike nanostructures over a large area of a quartz surface via a simple O2 and CF4 two-step reactive ion etching (RIE) procedure is developed. The nanostructured quartz surfaces are successfully combined with the engineered viral particles derived from hepatitis B virus capsid, yielding a novel 3D assay system with attomolar sensitivity, which has great potential for use in sensitive and early detection of various disease markers. [source] ChemInform Abstract: Two- and Three-Dimensional [IrSi] Networks in the Silicides Sm3Ir2Si2, HoIrSi, and YbIrSi.CHEMINFORM, Issue 44 2001Ratikanta Mishra Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] A New Approach for Health Monitoring of Structures: Terrestrial Laser ScanningCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 1 2007H. S. Park Three-dimensional (3D) coordinates of a target structure acquired using TLS can have maximum errors of about 10 mm, which is insufficient for the purpose of health monitoring of structures. A displacement measurement model is presented to improve the accuracy of the measurement. The model is tested experimentally on a simply supported steel beam. Measurements were made using three different techniques: (1) linear variable displacement transducers (LVDTs), (2) electric strain gages, and (3) a long gage fiber optic sensor. The maximum deflections estimated by the TLS model are less than 1 mm and within 1.6% of those measured directly by LVDT. Although GPS methods allow measurement of displacements only at the GPS receiver antenna location, the proposed TLS method allows measurement of the entire building's or bridge's deformed shape, and thus a realistic solution for monitoring structures at both structure and member level. Furthermore, it can be used to create a 3D finite element model of a structural member or the entire structure at any instance of time automatically. Through periodic measurements of deformations of a structure or a structural member and performing inverse structural analyses with the measured 3D displacements, the health of the structure can be monitored continuously. [source] Three-dimensional flow modelling and sediment transport in the River KlarälvenEARTH SURFACE PROCESSES AND LANDFORMS, Issue 7 2004Bijan Dargahi Abstract A three-dimensional ,ow model that uses the RNG k - , turbulence model and a non-equilibrium wall function was applied to the River Klarälven in the southwest part of Sweden. The objectives were to study the nature of the ,ow in the river bifurcation and to investigate the short-term sediment transport patterns in the river. The effectiveness of three-dimensional ,ow models depends upon: (1) how well the river geometry and it surface roughness are modelled; and (2) the choice of the closure model. Improvements were obtained by modelling the river in two parts: the entire river reach, and a selected part. Composite Manning coef,cients were used to account for roughness properties. The method requires a calibration process that ensures the water surface pro,les match the ,eld data. The k - , model under-predicted both the extent of ,ow separation zones and the number of secondary ,ow regions having a spiral motion, in comparison with the RNG k - , model. The 3-D model could predict with good accuracy both the general and secondary ,ow ,elds in the river. The results agreed well with the 3-D velocity measurements using an acoustic Doppler current pro,ler. A conceptual model was developed that accounts for the development of secondary ,ows in a river bifurcation having two bends. The main ,ow feature in the river cross-sections was the existence of multiple counter-rotating spiral motions. The number of spiral motions increased as the river bends were approached. The river bends also caused vorticity intensi,cation and increased the vertical velocities. The application of the 3-D ,ow model was extended by solving the sediment continuity equation. The sediment transport patterns were related to the secondary ,ow ,elds in the river. The sediment transport patterns at the river bifurcations are characterized by the growth of a sandbank. Copyright © 2004 John Wiley & Sons, Ltd. [source] Cyclic behavior of laterally loaded concrete piles embedded into cohesive soilEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 1 2008Rabin Tuladhar Abstract Modern seismic design codes stipulate that the response analysis should be conducted by considering the complete structural system including superstructure, foundation, and ground. However, for the development of seismic response analysis method for a complete structural system, it is first imperative to clarify the behavior of the soil and piles during earthquakes. In this study, full-scale monotonic and reversed cyclic lateral loading tests were carried out on concrete piles embedded into the ground. The test piles were hollow, precast, prestressed concrete piles with an outer diameter of 300,mm and a thickness of 60,mm. The test piles were 26,m long. Three-dimensional (3D) finite element analysis was then performed to study the behavior of the experimental specimens analytically. The study revealed that the lateral load-carrying capacity of the piles degrades when subjected to cyclic loading compared with monotonic loading. The effect of the use of an interface element between the soil and pile surface in the analysis was also investigated. With proper consideration of the constitutive models of soil and pile, an interface element between the pile surface and the soil, and the degradation of soil stiffness under cyclic loading, a 3D analysis was found to simulate well the actual behavior of pile and soil. Copyright © 2007 John Wiley & Sons, Ltd. [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] Analysis and design of band-pass frequency-selective surfaces using the FEM CAD toolINTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 5 2004P. T. Teo Abstract Three-dimensional (3D) full-wave analysis and design of bandpass frequency-selective surfaces (FSSs) is presented. By using the unique features of a unit cell and the periodic boundary conditions, infinite FSSs can be simulated. Wave propagation through FSSs, which is otherwise difficult to quantify, can be visualised by using a commercial CAD tool. The creation of the simulation model, interpretation and analysis of the outcome, and comparison with experimental results are presented for the square-slot and the square-loop-slot band-pass FSS. © 2004 Wiley Periodicals, Inc. Int J RF and Microwave CAE 14, 391,397, 2004. [source] Polysaccharide-based artificial extracellular matrix: Preparation and characterization of three-dimensional, macroporous chitosan, and heparin composite scaffoldJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008Shu-Huei Yu Abstract Scaffold-guided tissue engineering based on synthetic and natural occurring polymers has gained many interests in recent year. In this study, the development of a chitosan-heparin artificial extracellular matrix (AECM) is reported. Three-dimensional, macroporous composite AECMs composed of heparin (Hep) and chitosan (Chito) were prepared by an interpolyelectrolyte complex/lyophilization method. The Chito-Hep composite AECMs were, respectively, crosslinked with glutaraldehyde, as well as cocrosslinked with N,N -(3-dimethylaminopropyl)- N,-ethyl carbodiimide (EDC/NHS) and N -hydroxysuccinimide (NHS). The crosslinking reactions were examined by FT-IR analysis. In physiological buffer solution (PBS), the EDC/NHS-crosslinked Chito-Hep composite AECM showed a relative lower water retention ratio than its glutaraldehyde-crosslinked counterparts. The EDC/NHS-crosslinked Chito-Hep composite AECMs showed excellent biocompatibility, according to the results of the in vitro cytotoxic test. This result suggested that the EDC/NHS-crosslinked Chito-Hep composite AECMs might be a potential biomaterial for scaffold-guided tissue engineering applications. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Chitosan scaffolds for in vitro buffalo embryonic stem-like cell culture: An approach to tissue engineeringJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2007Wah W. Thein-Han Abstract Three-dimensional (3D) porous chitosan scaffolds are attractive candidates for tissue engineering applications. Chitosan scaffolds of 70, 88, and 95% degree of deacetylation (% DD) with the same molecular weight were developed and their properties with buffalo embryonic stem-like (ES-like) cells were investigated in vitro. Scaffolds were fabricated by freezing and lyophilization. They showed open pore structure with interconnecting pores under scanning electron microscopy (SEM). Higher % DD chitosan scaffolds had greater mechanical strength, slower degradation rate, lower water uptake ability, but similar water retention ability, when compared to lower % DD chitosan. As a strategy to tissue engineering, buffalo ES-like cells were cultured on scaffolds for 28 days. It appeared that chitosan was cytocompatible and cells proliferated well on 88 and 95% DD scaffolds. In addition, the buffalo ES-like cells maintained their pluripotency during the culture period. Furthermore, the SEM and histological study showed that the polygonal buffalo ES-like cells proliferated well and attached to the pores. This study proved that 3D biodegradable highly deacetylated chitosan scaffolds are promising candidates for ES-like cell based tissue engineering and this chitosan scaffold and ES cell based system can be used as in vitro model for subsequent clinical applications. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007 [source] Three-dimensional balanced steady state free precession imaging of the prostate: Flip angle dependency of the signal based on a two component T2-decay modelJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 5 2010Tryggve H. Storås MS Abstract Purpose: To investigate the contrast of three-dimensional balanced steady state free precession (3D bSSFP) in the two component T2 model and to apply the results to optimize 3D bSSFP for prostate imaging at 1.5 Tesla. Materials and Methods: In each of seven healthy volunteers, six 3D bSSFP acquisitions were performed with flip angles (,) equally spaced between 10° and 110°. Predictions of signal and contrast were obtained from synthetic bSSFP images calculated from relaxation parameters obtained from a multi-spin-echo acquisition. One biexponential and two monoexponential models were applied. Measured and predicted signals were compared by simple linear regression. Results: The measured contrast to signal ratio increased continuously with ,. Mean R2 for the biexponential model was almost constant for , in the range 50,110°. The biexponential model was a better predictor of the measured signal than the monoexponential model. A monoexponential model restricted to the echoes TE = 50,125 ms performed similar to the biexponential model. The predicted contrast peaked at , between 50° and 90°. Conclusion: Prostate imaging with bSSFP benefited from high flip angles. The biexponential model provided good signal prediction while predictions from the monoexponential models are dependent on the range of TE used for T2 determination. J. Magn. Reson. Imaging 2010;31:1124,1131. © 2010 Wiley-Liss, Inc. [source] Quantitative characterization of sphere-templated porous biomaterialsAICHE JOURNAL, Issue 4 2005A. J. Marshall Abstract Three-dimensional (3-D) porous hydrogels were fabricated by polymerizing 2-hydroxyethyl methacrylate around templates of random close-packed poly(methyl methacrylate) microspheres with nominal diameter of 5 or 15 ,m. The templates were leached out to create networks of interconnected spherical pores. Applications for sphere-templated porous biomaterials include scaffolds for tissue engineering and spatial control of wound healing. This study describes an approach to characterizing pore structure and predicting permeability of sphere-templated porous hydrogels. The materials were embedded in resin, and 1-,m-plane sections were digitally analyzed with fluorescence microscopy. The porosity and pore size distribution were determined from stereological interpretation, and we present novel techniques for obtaining the pore throat size distribution, the number of pore throats per pore, and the tortuosity. A simple apparatus is also introduced for measurement of the hydraulic permeability. Permeability predictions based on quantitative microscopy measurements and on stereology were found to agree closely with permeability measurements. The aptness of the Kozeny equation for spherically pored materials is also investigated. © 2005 American Institute of Chemical Engineers AIChE J, 2005 [source] Seafloor glacial features reveal the extent and decay of the last British Ice Sheet, east of Scotland,JOURNAL OF QUATERNARY SCIENCE, Issue 2 2009Alastair G. C. Graham Abstract Three-dimensional (3D) seismic datasets, 2D seismic reflection profiles and shallow cores provide insights into the geometry and composition of glacial features on the continental shelf, offshore eastern Scotland (58° N, 1,2° W). The relic features are related to the activity of the last British Ice Sheet (BIS) in the Outer Moray Firth. A landsystem assemblage consisting of four types of subglacial and ice marginal morphology is mapped at the seafloor. The assemblage comprises: (i) large seabed banks (interpreted as end moraines), coeval with the Bosies Bank moraine; (ii) morainic ridges (hummocky, push and end moraine) formed beneath, and at the margins of the ice sheet; (iii) an incised valley (a subglacial meltwater channel), recording meltwater drainage beneath former ice sheets; and (iv) elongate ridges and grooves (subglacial bedforms) overprinted by transverse ridges (grounding line moraines). The bedforms suggest that fast-flowing grounded ice advanced eastward of the previously proposed terminus of the offshore Late Weichselian BIS, increasing the size and extent of the ice sheet beyond traditional limits. Complex moraine formation at the margins of less active ice characterised subsequent retreat, with periodic stillstands and readvances. Observations are consistent with interpretations of a dynamic and oscillating ice margin during BIS deglaciation, and with an extensive ice sheet in the North Sea basin at the Last Glacial Maximum. Final ice margin retreat was rapid, manifested in stagnant ice topography, which aided preservation of the landsystem record. Copyright © 2008 John Wiley & Sons, Ltd. [source] Three-dimensional chemical mapping by scanning transmission X-ray spectromicroscopyJOURNAL OF SYNCHROTRON RADIATION, Issue 5 2007Göran A. Johansson Three-dimensional (3-d) chemical mapping using angle-scan tomography in a scanning transmission X-ray microscope is demonstrated. Apparatus, experimental procedures and data processing are presented and the 3-d spatial resolution is evaluated. The technique is illustrated using mapping of a low-density acrylate polyelectrolyte in and outside of polystyrene microspheres dispersed in water in a 4,µm-diameter microcapillary. The 3-d chemical visualization provides information about the microstructure that had not previously been observed. [source] Fabrication of Three-Dimensional Micro Photonic Crystals of Resin-Incorporating TiO2 Particles and their Terahertz Wave PropertiesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2007Weiwu Chen Three-dimensional (3D) photonic crystals with a diamond structure made from 40 vol% TiO2,acrylate dielectric composites were formed by means of a CAD/CAM micro-stereolithography system. The lattice constant of the diamond unit cell was 500 ,m and the forming accuracy was 10 ,m. The photonic band gap in the ,,X ,100, direction measured by terahertz-time-domain spectroscopy appeared at 280,360 GHz, which agreed fairly well with the band gap calculated by the plane wave expansion method. [source] Cyclic acetal hydroxyapatite composites and endogenous osteogenic gene expression of rat marrow stromal cellsJOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Issue 6 2010Minal Patel Abstract In this study, bone marrow stromal cells (BMSCs) were differentiated on cyclic acetal composites containing hydroxyapatite (HA) particles (110 or 550 nm). These composites were evaluated for their role in influencing osteogenic signalling by encapsulated BMSCs. While a number of factors exert influence on osteogenic signalling during the production of an osteogenic matrix, we hypothesize that HA particles may upregulate bone growth factor expression due to enhanced BMSC adhesion. To this end, fluorescence-activated cell sorting (FACS) analysis was performed for the evaluation of BMSC surface marker expression after culture on two-dimensional (2D) cyclic acetal/HA composites. Three-dimensional (3D) composites were then fabricated by incorporating 110 or 550 nm HA particles at 5, 10 and 50 ng/ml concentrations. Bone growth factor molecules (TGF,1, FGF-2 and PDGFa), bone biomarker molecules (ALP, OC, OPN and OCN) and extracellular matrix-related molecules (FN, MMP-13, Dmp1 and aggrecan) were selected for evaluation of osteogenic signalling mechanisms when in presence of these composites. FACS results at day 0 demonstrated that BMSCs were a heterogeneous population with a small percentage of cells staining positive for CD29, CD90 and CD51/61, while staining negative for CD34 and CD45. At day 3, a significant enrichment of cells staining strongly for CD29, CD90 and CD51/61 was achieved. Gene expression patterns for bone growth factors and extracellular matrix molecules were found to be largely dependent upon the size of HA particles. Bone marker molecules, except OCN, had unaltered expression patterns in response to the varied size of HA particles. Overall, the results indicate that larger-sized HA particles upregulate PDGF and these groups were also associated with the most significant increase in osteodifferentiation markers, particularly ALP. Our results suggest that endogenous signalling is dependent upon material properties. Furthermore, we propose that studying gene expression patterns induced by the surrounding biomaterials environment is a fundamental step in the creation of engineered tissues. Copyright © 2010 John Wiley & Sons, Ltd. [source] "Sponge-like" structures in polymer blends: visualization, physico-mathematical analysis, and universalityMACROMOLECULAR SYMPOSIA, Issue 1 2002Takeji Hashimoto Mesoscopic structures formed during an ordering process in thermodynamically unstable, isometric, binary molecular mixtures were explored by time-resolved scattering (TRS) and laser scanning confocal microscopy (LSCM). Three-dimensional (3D) bicontinuous structures, which were constructed for the first time by time-resolved LSCM, were found to have a "sponge-like" structure composed of two phases. The structure factor obtained by 3D Fourier transformation of the sponge was found to be identical to that obtained by TRS, confirming that the sponge truly reflects the structural entities evolving in the system. Furthermore, the sponge was shown for the first time to be theoretically predictable by using 3D computer simulations based on the time-dependent Ginzburg-Landau theory. The sponge was subjected to differential geometrical analysis: its Gaussian curvature K, mean curvature H, and their distributions were successfully determined for the first time. The result revealed that the sponge has hyperbolic interfaces with area-averaged curvatures satisfying Systolic 3D first-pass myocardial perfusion MRI: Comparison with diastolic imaging in healthy subjectsMAGNETIC RESONANCE IN MEDICINE, Issue 4 2010Taehoon Shin Abstract Three-dimensional (3D) first-pass myocardial perfusion imaging (MPI) is a promising alternative to conventional two-dimensional multislice MPI due to its contiguous spatial coverage that is beneficial for estimating the size of perfusion defects. Data acquisition at mid-diastole is a typical choice for 3D MPI yet is sensitive to arrhythmia and variations in R-R interval that are common in cardiac patients. End systole is the second longest quiescent cardiac phase and is known to be less sensitive to the R-R variability. Therefore, 3D MPI with systolic acquisition may be advantageous in patients with severe arrhythmia once it is proven to be comparable to diastolic MPI in subjects with negligible R-R variation. In this work, we demonstrate the feasibility of 3D MPI with systolic data acquisition in five healthy subjects. We performed 3D MPI experiments in which 3D perfusion data were acquired at both end-systole and mid-diastole of every R-R interval and analyzed the similarity between resulting time intensity curves (TIC) from the two data sets. The correlation between systolic and diastolic TICs was extremely high (mean = 0.9841; standard deviation = 0.0166), and there was a significant linear correlation between the two time intensity curve upslopes and peak enhancements (P < 0.001). Magn Reson Med 63:858,864, 2010. © 2010 Wiley-Liss, Inc. [source] Fast three-dimensional k -space trajectory design using missile guidance ideasMAGNETIC RESONANCE IN MEDICINE, Issue 2 2004Roberto Mir Abstract Three-dimensional (3D) k -space trajectories are needed to acquire volumetric images in MRI. While scan time is determined by the trajectory efficiency, image quality and distortions depend on the shape of the trajectories. There are several 3D trajectory strategies for sampling the k -space using rectilinear or curve schemes. Since there is no evidence about their optimality in terms of image quality and acquisition time, a new design method based on missile guidance ideas is explored. Since air-to-air missile guidance shares similar goals and constraints with the problem of k -space trajectory design, a control approach for missiles is used to design a 3D trajectory. The k -space is divided into small cubes, and each one is treated as a target to be sampled. The main goal is to cover the entire space as quickly and efficiently as possible, with good performance under different conditions. This novel design method is compared to other trajectories using simulated and real data. As an example, a trajectory that requires 0.11 times the number of shots needed by the cylindrical 3DFT acquisition was designed. This trajectory requires more shots (1.66 times) than the stack of spirals, but behaves better under nonideal conditions, such as off-resonance and motion. Magn Reson Med 52:329,336, 2004. © 2004 Wiley-Liss, Inc. [source] Real-time Integration of Intracardiac Echocardiography and Electroanatomic Mapping in PVCs Arising from the LV Anterior Papillary MusclePACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 9 2009Ph.D., TAKUMI YAMADA M.D. A 54-year-old woman with idiopathic premature ventricular contractions (PVCs) underwent electrophysiological testing. Three-dimensional (3D) geometries of the papillary muscles and chamber of the left ventricle (LV) were reconstructed using a CARTO-based 3D ultrasound imaging system (Biosense Webster Inc., Diamond Bar, CA, USA) during the PVCs. Activation mapping in the LV was then performed during the PVCs and the activation map revealed the earliest ventricular activation on the anterior papillary muscle. An irrigated radiofrequency current delivered at that site with guidance from that system eliminated the PVCs. This case may suggest that the guidance system may be feasible and useful for catheter ablation of PVCs arising from uncommon sites. [source] Coupling 3D and 1D fluid-structure interaction models for blood flow simulationsPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2006L. Formaggia Three-dimensional (3D) simulations of blood flow in medium to large vessels are now a common practice. These models consist of the 3D Navier-Stokes equations for incompressible Newtonian fluids coupled with a model for the vessel wall structure. However, it is still computationally unaffordable to simulate very large sections, let alone the whole, of the human circulatory system with fully 3D fluid-structure interaction models. Thus truncated 3D regions have to be considered. Reduced models, one-dimensional (1D) or zero-dimensional (0D), can be used to approximate the remaining parts of the cardiovascular system at a low computational cost. These models have a lower level of accuracy, since they describe the evolution of averaged quantities, nevertheless they provide useful information which can be fed to the more complex model. More precisely, the 1D models describe the wave propagation nature of blood flow and coupled with the 3D models can act also as absorbing boundary conditions. We consider in this work the coupling of a 3D fluid-structure interaction model with a 1D hyperbolic model. We study the stability of the coupling and present some numerical results. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Measurement of total body composition changes of common carp by computer tomographyAQUACULTURE RESEARCH, Issue 12 2003Csaba Hancz Abstract The crude fat and protein content of the total body was estimated by X-ray computer tomography (CT) and determined by chemical analyses during a feeding experiment with sexually matured common carp. Between 21 and 35 serial scans were taken of altogether 41 fish and samples from the homogenized body were prepared for chemical analyses. Experimental fish with an average body weight of 1453 g originated from a commercial stock of mirror carp. Two feeding regimes (carp feed and carp feed+ad libitum maize) were applied for 57 days and followed by a fasting period of 27 days. Both feeding regimes significantly increased the crude fat content of the whole body that did not decrease during fasting in spite of high water temperature (22°C). No significant changes were observed in crude protein content. The variables used for producing the prediction equations were taken from the density values of the Hounsfield scale, on a range between ,90 and +160, by summing the frequencies within each interval of 10 values. Whole body fat content could be estimated with R2=0.89,0.91 accuracy with the principal component analysis using data of all (seven) body regions and only dorsal fin region respectively. Adequate linear regression model could not be calculated by the same procedure for crude protein. Three-dimensional ,volumetric' estimation of fat tissue was also carried out on the basis of fat index showing high correlation with measured fat content. The changes of body composition of individual fish can be followed by sequential CT scanning. [source] Three-dimensional, multi-offset ground-penetrating radar imaging of archaeological targetsARCHAEOLOGICAL PROSPECTION, Issue 2 2008Adam D. Booth Abstract The efficacy of ground penetrating radar (GPR) methods is inhibited when surveying over a target that is structurally complex and/or hosted within attenuative media. Recent research has documented the ability of certain seismic methods to improve imaging using GPR. For imaging complex targets, three-dimensional acquisition and migration methods are applied. For attenuative sites, signal-to- noise ratio (SNR) may be boosted on acquisition of multi-offset data. We present results from an integrated three-dimensional multi-offset survey over a Romano-British villa at Groundwell Ridge, near Swindon, UK. Data were acquired within a grid of dimension 21,m,×,14,m, using a single-channel PulseEKKO GPR system equipped with common-offset (CO) 450,MHz antennas. To satisfy criteria for three-dimensional migration, the sample density over the grid was 0.05,×,0.05,m2. A smaller grid of three-dimensional multi-offset data was acquired, with fold-of-cover 2200%, targeting a low SNR section of data. The spatial resolution and SNR in the resulting images of the target are greatly improved compared with data acquired using a more conventional survey method. However, this improvement may not be justified by the greatly increased (some 10 times) fieldwork effort required to obtain three-dimensional multi-offset data. We therefore investigate a means of improving the efficiency of three-dimensional GPR surveying by applying a simple trace interpolation method to recover three-dimensional acquisition criteria. This trial suggests that, at this site, three-dimensional data can be simulated from a grid of pseudo-three-dimensional data, sampled at 0.05,×,0.25,m2. In this way, high quality images of an archaeological target can be obtained with minimal increase to survey effort. We hope that, on the basis of this work, three-dimensional and multi-offset acquisitions will be more readily considered for archaeological GPR investigations. Copyright © 2008 John Wiley & Sons, Ltd. [source] Centrifugal seeding of mammalian cells in nonwoven fibrous matricesBIOTECHNOLOGY PROGRESS, Issue 1 2010Robin Ng Abstract Three-dimensional (3D) cell cultures have many advantages over two-dimensional cultures. However, seeding cells in 3D scaffolds such as nonwoven fibrous polyethylene terephthalate (PET) matrices has been a challenge task in tissue engineering and cell culture bioprocessing. In this study, a centrifugal seeding method was investigated to improve the cell seeding efficiency in PET matrices with two different porosities (93% and 88%). Both the centrifugal force and centrifugation time were found to affect the seeding efficiency. With an appropriate centrifugation speed, a high 80,90% cell seeding efficiency was achieved and the time to reach this high seeding efficiency was less than 5 min. The seeding efficiency was similar for matrices with different porosities, although the optimal seeding time was significantly shorter for the low-porosity scaffold. Post seeding cell viability was demonstrated by culturing colon cancer cells seeded in PET matrices for over 5 days. The centrifugal seeding method developed in this work can be used to efficiently and uniformly seed small fibrous scaffolds for applications in 3D cell-based assays for high-throughput screening. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source] Wilms tumor gene protein 1 is associated with ovarian cancer metastasis and modulates cell invasionCANCER, Issue 7 2008Maria V. Barbolina PhD Abstract BACKGROUND Although metastatic disease is the primary cause of death from epithelial ovarian carcinoma, to the authors' knowledge the cellular mechanisms that regulate intraperitoneal metastasis are largely unknown. Metastasizing ovarian carcinoma cells encounter a collagen-rich microenvironment because the submesothelial matrix is comprised mainly of interstitial collagens Types I and III. METHODS Immunohistochemistry using primary and metastatic ovarian carcinoma samples was employed to detect expression of Wilms tumor gene protein 1 (WT1). Three-dimensional (3D) collagen culture, real-time reverse transcriptase-polymerase chain reaction, and immunofluorescent staining were used to evaluate changes in WT1 RNA and protein expression in response to 3D collagen culture. Boyden chamber invasion assay, scratch-wound motility assay, and Western blot analysis were used to establish the function of WT1 in ovarian carcinoma cells. RESULTS To model intraperitoneal invasion in vitro, ovarian cancer cells were cultured in a 3D collagen microenvironment. 3D collagen culture resulted in robust induction of WT1 at the mRNA and protein levels. WT1 expression was prevalent in primary ovarian tumors and was retained in paired peritoneal metastases. Functional studies supported a role for WT1 in intraperitoneal invasion, because siRNA knockdown of WT1 expression reduced the ability of ovarian cancer cells to invade 3D collagen gels. CONCLUSIONS The data from the current study identify a novel regulatory mechanism for the control of WT1 expression and provide evidence for a functional role of WT1 protein in the control of cellular invasive activity. Cancer 2008. ©2008 American Cancer Society. [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] Progressive brain changes in schizophrenia: a 1-year follow-up study of diffusion tensor imagingACTA NEUROPSYCHIATRICA, Issue 6 2009Miho Ota Objective: Recent cross-sectional studies suggest that brain changes in schizophrenia are progressive during the course of the disorder. However, it remains unknown whether this is a global process or whether some brain areas are affected to a greater degree. The aim of this study was to examine the longitudinal brain changes in patients with chronic older schizophrenia by magnetic resonance imaging (MRI). Methods: Three-dimensional (3D) T1-weighted and diffusion tensor (DT) MRI were performed twice on each of 16 chronic older schizophrenia patients (mean age = 58.1 ± 6.7 years ) with an interval of 1 year between imaging sessions. To clarify the longitudinal morphological and white matter changes, volume data and normalised diffusion tensor imaging (DTI) metrics were compared between the first and follow-up studies using a paired t -test. Results: Focal cortical volume loss was observed in the left prefrontal lobe and anterior cingulate on volumetric study. In addition, DTI metrics changed significantly at the bilateral posterior superior temporal lobes, left insula, genu of the corpus callosum and anterior cingulate. Conclusion: There are ongoing changes in the brains of schizophrenic patients during the course of the illness. Discrepancies between volume data and DTI metrics may indicate that the pattern of progressive brain changes varies according to brain region. [source] The Pheromone Production of Female Plodia interpunctella Is Inhibited by Tyraminergic AntagonistsCHEMISTRY & BIODIVERSITY, Issue 11 2004Akinori Hirashima Several compounds were found to suppress the calling behavior and in vitro pheromone biosynthesis of the Indian meal moth, Plodia interpunctella. The compounds were screened by means of a calling-behavior bioassay with female P. interpunctella. Five derivatives with activities in the nanomolar range were identified, in order of decreasing pheromonostatic activity: 4-hydroxybenzaldehyde semicarbazone (42) >5-(4-methoxyphenyl)-1,3-oxazole (38) >5-[4-(tert -butyl)phenyl]-1,3-oxazole (40) >5-(3-methoxyphenyl)-1,3-oxazole (35) >5-(4-cyanophenyl)-1,3-oxazole (36). These compounds also showed in vitro inhibitory activity in intracellular de novo pheromone biosynthesis, as determined with isolated pheromone-gland preparations that incorporated [1- 14C]sodium acetate in the presence of the so-called pheromone-biosynthesis-activating neuropeptide (PBAN). The non-additive effect of the inhibitor with antagonist (yohimbine) for the tyramine (TA) receptor suggests that it could be a tyraminergic antagonist. Three-dimensional (3D) computer models were built from a set of compounds. Among the common-featured models generated by the program Catalyst/HipHop, aromatic-ring (AR) and H-bond-acceptor-lipophilic (HBAl) features were considered to be essential for inhibitory activity in the calling behavior and in vitro pheromone biosynthesis. Active compounds, including yohimbine, mapped well onto all the AR and HBAl features of the hypothesis. Less-active compounds were shown to be unable to achieve an energetically favorable conformation, consistent with our 3D common-feature pharmacophore models. The present hypothesis demonstrates that calling behavior and PBAN-stimulated incorporation of radioactivity are inhibited by tyraminergic antagonists. [source] Development of Three-Dimensional Object Completion in InfancyCHILD DEVELOPMENT, Issue 5 2008Kasey C. Soska Three-dimensional (3D) object completion was investigated by habituating 4- and 6-month-old infants (n= 24 total) with a computer-generated wedge stimulus that pivoted 15°, providing only a limited view. Two displays, rotating 360°, were then shown: a complete, solid volume and an incomplete, hollow form composed only of the sides seen during habituation. There were no reliable preferences for either test display by 4-month-olds. At 6 months, infants showed a reliable novelty preference for the incomplete test display. Infants in a control group (n= 24) not habituated to the limited-view wedge preferred neither test display. By 6 months, infants may represent simple objects as complete in 3D space despite a limited perspective. Possible mechanisms of development of 3D object completion are discussed. [source] CAD/CAM fabrication and clinical application of surgical template and bone model in oral implant surgeryCLINICAL ORAL IMPLANTS RESEARCH, Issue 1 2009Taiji Sohmura Abstract Objectives: A novel implant surgery support system with computer simulation for implant insertion and fabrication of a surgical template that helps in drilling bone was developed. A virtual reality haptic device that gives the sense of touch was used for simulation and a surgical template was fabricated by CAD/CAM method. Surgical guides were applied for two clinical cases. Material and methods: Three-dimensional (3D) jaw bone images transferred from DICOM data filmed by CT scanner were fed to the software and manipulated using the haptic device. The site for implant insertion was determined after evaluating the quality of bone and position of the mandibular canal. The surgical template was designed with ease using the free design CAD function of haptic device. The surgical template and bone model were fabricated by a fused deposit modeling machine. Two clinical cases were applied using the present system. Results: Simulation to determine the site of implant insertion and fabrication of the surgical bone templates were successfully done in two clinical cases, one for three implant insertion in lower right jaw and the other is for seven implant insertion in lower edentulous jaw, respectively. During surgery, the templates could be firmly adapted on the bone and drilling was successfully performed in both cases. Conclusion: The present simulation and drilling support using the surgical template may help to perform safe and accurate implant surgery. [source] A comparative study of 3D scanning in engineering, product and transport design and fashion design educationCOMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 3 2009A. Kus Abstract The aim of this paper is to evaluate the use of three-dimensional (3D) scanning technologies for design and engineering courses. This paper will provide a comparative discussion of the current 3D scanning technologies; and then describes three experimental studies in engineering, transport design and fashion design. Using 3D scanner technology the experiments tested the transferral of a variety of different data from scanned organic 3D shapes to 3D CAD packages for learning and teaching in undergraduate education. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 17: 263,271, 2009; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20213 [source]
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