NASA Astrophysics Data System (ADS)
Aguirre, Andres; Guo, Puyun; Gamelin, John; Yan, Shikui; Sanders, Mary M.; Brewer, Molly; Zhu, Quing
2009-09-01
Ovarian cancer has the highest mortality of all gynecologic cancers, with a five-year survival rate of only 30% or less. Current imaging techniques are limited in sensitivity and specificity in detecting early stage ovarian cancer prior to its widespread metastasis. New imaging techniques that can provide functional and molecular contrasts are needed to reduce the high mortality of this disease. One such promising technique is photoacoustic imaging. We develop a 1280-element coregistered 3-D ultrasound and photoacoustic imaging system based on a 1.75-D acoustic array. Volumetric images over a scan range of 80 deg in azimuth and 20 deg in elevation can be achieved in minutes. The system has been used to image normal porcine ovarian tissue. This is an important step toward better understanding of ovarian cancer optical properties obtained with photoacoustic techniques. To the best of our knowledge, such data are not available in the literature. We present characterization measurements of the system and compare coregistered ultrasound and photoacoustic images of ovarian tissue to histological images. The results show excellent coregistration of ultrasound and photoacoustic images. Strong optical absorption from vasculature, especially highly vascularized corpora lutea and low absorption from follicles, is demonstrated.
NASA Astrophysics Data System (ADS)
Li, Jiawen; Ma, Teng; Jing, Joseph; Zhang, Jun; Patel, Pranav M.; Shung, K. Kirk; Zhou, Qifa; Chen, Zhongping
2014-03-01
We have developed a novel integrated optical coherence tomography (OCT)-intravascular ultrasound (IVUS) probe, with a 1.5 mm-long rigid-part and 0.9 mm outer diameter, for real-time intracoronary imaging of atherosclerotic plaques and guiding interventional procedures. By placing the OCT ball lens and IVUS 45MHz single element transducer back-to-back at the same axial position, this probe can provide automatically co-registered, co-axial OCT-IVUS imaging. To demonstrate its capability, 3D OCT-IVUS imaging of a pig's coronary artery in real-time displayed in polar coordinates, as well as images of two major types of advanced plaques in human cadaver coronary segments, was obtained using this probe and our upgraded system. Histology validation is also presented.
Co-registered photoacoustic, thermoacoustic, and ultrasound mouse imaging
NASA Astrophysics Data System (ADS)
Reinecke, Daniel R.; Kruger, Robert A.; Lam, Richard B.; DelRio, Stephen P.
2010-02-01
We have constructed and tested a prototype test bed that allows us to form 3D photoacoustic CT images using near-infrared (NIR) irradiation (700 - 900 nm), 3D thermoacoustic CT images using microwave irradiation (434 MHz), and 3D ultrasound images from a commercial ultrasound scanner. The device utilizes a vertically oriented, curved array to capture the photoacoustic and thermoacoustic data. In addition, an 8-MHz linear array fixed in a horizontal position provides the ultrasound data. The photoacoustic and thermoacoustic data sets are co-registered exactly because they use the same detector. The ultrasound data set requires only simple corrections to co-register its images. The photoacoustic, thermoacoustic, and ultrasound images of mouse anatomy reveal complementary anatomic information as they exploit different contrast mechanisms. The thermoacoustic images differentiate between muscle, fat and bone. The photoacoustic images reveal the hemoglobin distribution, which is localized predominantly in the vascular space. The ultrasound images provide detailed information about the bony structures. Superposition of all three images onto a co-registered hybrid image shows the potential of a trimodal photoacoustic-thermoacoustic-ultrasound small-animal imaging system.
Opto-acoustic breast imaging with co-registered ultrasound
NASA Astrophysics Data System (ADS)
Zalev, Jason; Clingman, Bryan; Herzog, Don; Miller, Tom; Stavros, A. Thomas; Oraevsky, Alexander; Kist, Kenneth; Dornbluth, N. Carol; Otto, Pamela
2014-03-01
We present results from a recent study involving the ImagioTM breast imaging system, which produces fused real-time two-dimensional color-coded opto-acoustic (OA) images that are co-registered and temporally inter- leaved with real-time gray scale ultrasound using a specialized duplex handheld probe. The use of dual optical wavelengths provides functional blood map images of breast tissue and tumors displayed with high contrast based on total hemoglobin and oxygen saturation of the blood. This provides functional diagnostic information pertaining to tumor metabolism. OA also shows morphologic information about tumor neo-vascularity that is complementary to the morphological information obtained with conventional gray scale ultrasound. This fusion technology conveniently enables real-time analysis of the functional opto-acoustic features of lesions detected by readers familiar with anatomical gray scale ultrasound. We demonstrate co-registered opto-acoustic and ultrasonic images of malignant and benign tumors from a recent clinical study that provide new insight into the function of tumors in-vivo. Results from the Feasibility Study show preliminary evidence that the technology may have the capability to improve characterization of benign and malignant breast masses over conventional diagnostic breast ultrasound alone and to improve overall accuracy of breast mass diagnosis. In particular, OA improved speci city over that of conventional diagnostic ultrasound, which could potentially reduce the number of negative biopsies performed without missing cancers.
Three-dimensional ultrasound imaging of the vasculature.
Fenster, A; Lee, D; Sherebrin, S; Rankin, R; Downey, D
1998-02-01
With conventional ultrasonography, the diagnostician must view a series of two-dimensional images in order to form a mental impression of the three-dimensional anatomy, an efficient and time consuming practice prone to operator variability, which may cause variable or even incorrect diagnoses. Also, a conventional two-dimensional ultrasound image represents a thin slice of the patients anatomy at a single location and orientation, which is difficult to reproduce at a later time. These factors make conventional ultrasonography non-optimal for prospective or follow-up studies. Our efforts have focused on overcoming these deficiencies by developing three-dimensional ultrasound imaging techniques that are capable of acquiring B-mode, colour Doppler and power Doppler images of the vasculature, by using a conventional ultrasound system to acquire a series of two-dimensional images and then mathematically reconstructing them into a single three-dimensional image, which may then be viewed interactively on an inexpensive desktop computer. We report here on two approaches: (1) free-hand scanning, in which a magnetic positioning device is attached to the ultrasound transducer to record the position and orientation of each two-dimensional image needed for the three-dimensional image reconstruction; and (2) mechanical scanning, in which a motor-driven assembly is used to translate the transducer linearly across the neck, yielding a set of uniformly-spaced parallel two-dimensional images.
Three-dimensional ultrasound evaluation of the placenta.
Hata, T; Tanaka, H; Noguchi, J; Hata, K
2011-02-01
Conventional two-dimensional (2D) ultrasound has been widely used for the evaluation of the placenta during pregnancy. This 2D ultrasound evaluation includes the morphology, anatomy, location, implantation, anomaly, size, and color/power and pulsed Doppler sonographic assessment of the placenta. The introduction of three-dimensional (3D) ultrasound would facilitate the novel assessment of the placenta, such as surface-rendered imaging and volume measurement. With the recent advances in 3D power Doppler (3DPD) ultrasound as well as quantitative 3DPD histogram analysis, quantitative and qualitative assessments of the vascularization and blood flow of the placenta have become feasible. These novel techniques may assist in the evaluation of the feto-placental function, and offer potential advantages relative to conventional 2D sonographic assessments. 3D ultrasound may be an important modality in future placental research, in the evaluation of feto-placental insufficiency in clinical practice, and in the prediction of fetal growth restriction and pre-eclampsia, although some limitations regarding the assessment of the placenta employing 3D ultrasound still remain unresolved.
In vivo three-dimensional photoacoustic imaging based on a clinical matrix array ultrasound probe
NASA Astrophysics Data System (ADS)
Wang, Yu; Erpelding, Todd N.; Jankovic, Ladislav; Guo, Zijian; Robert, Jean-Luc; David, Guillaume; Wang, Lihong V.
2012-06-01
We present an integrated photoacoustic and ultrasonic three-dimensional (3-D) volumetric imaging system based on a two-dimensional (2-D) matrix array ultrasound probe. A wavelength-tunable dye laser pumped by a Q-switched Nd:YAG laser serves as the light source and a modified commercial ultrasound imaging system (iU22, Philips Healthcare) with a 2-D array transducer (X7-2, Philips Healthcare) detects both the pulse-echo ultrasound and photoacoustic signals. A multichannel data acquisition system acquires the RF channel data. The imaging system enables rendering of co-registered 3-D ultrasound and photoacoustic images without mechanical scanning. The resolution along the azimuth, elevation, and axial direction are measured to be 0.69, 0.90 and 0.84 mm for photoacoustic imaging. In vivo 3-D photoacoustic mapping of the sentinel lymph node was demonstrated in a rat model using methylene blue dye. These results highlight the clinical potential of 3-D PA imaging for identification of sentinel lymph nodes for cancer staging in humans.
NASA Astrophysics Data System (ADS)
Speicher, Daniel; Bartscherer, T.; Becker, F. J.; Jenne, J. W.; Mrosk, K.; Degel, C.; Günther, M.; Tretbar, S.
Magnetic resonance imaging has become an important part of radiological diagnostics as it shows high resolution volumes of human tissue without any radiation exposure. Beside the high costs for MR imaging the greatest disadvantage of this technology is that it is not real-time capable which leads to possible motion artifacts. Whereas Ultrasound is the most common diagnostic tool in radiology as it is real-time capable and cost effective. Therefore a combination of both modalities is obvious, not only to reduce motion artifacts in MR imaging but to save costs by reducing time in the MR scanner through coregistering ultrasound and MR images for deformation analysis. This work presents the manufacturing and measurement results of MR compatible ultrasound transducers for motion compensation and deformation analyses for clinical interventions under MRI conditions, based on ultrasound volumes acquired by a full MR compatible 180° rotating 8 MHz phased array.
Ermilov, S A; Su, R; Conjusteau, A; Anis, F; Nadvoretskiy, V; Anastasio, M A; Oraevsky, A A
2016-01-01
In this work, we introduce a novel three-dimensional imaging system for in vivo high-resolution anatomical and functional whole-body visualization of small animal models developed for preclinical and other type of biomedical research. The system (LOUIS-3DM) combines a multiwavelength optoacoustic tomography (OAT) and laser-induced ultrasound tomography (LUT) to obtain coregistered maps of tissue optical absorption and speed of sound, displayed within the skin outline of the studied animal. The most promising applications of the LOUIS-3DM include 3D angiography, cancer research, and longitudinal studies of biological distributions of optoacoustic contrast agents.
Three-dimensional photoacoustic imaging with a clinical two-dimensional matrix ultrasound transducer
NASA Astrophysics Data System (ADS)
Erpelding, Todd N.; Wang, Yu; Jankovic, Ladislav; Guo, Zijian; Robert, Jean-Luc; David, Guillaume; Kim, Chulhong; Wang, Lihong V.
2011-03-01
Photoacoustic tomography provides both structural and functional imaging in vivo based on optical absorption contrast. A novel imaging system that incorporates a two-dimensional matrix ultrasound probe for combined photoacoustic and ultrasonic three-dimensional (3D) volumetric imaging is presented. The system consists of a tunable dye laser pumped by a Nd:YAG laser, a commercial ultrasound imaging system (Philips iU22) with a two-dimensional matrix transducer (Philips X7-2, 2500 elements, 2-7 MHz), and a multichannel data acquisition system which allows us to acquire RF channel data. Compared with alternative 3D techniques, this system is attractive because it can generate co-registered 3D photoacoustic and ultrasound images without mechanical scanning. Moreover, the lateral resolution along the azimuth and elevational directions are measured to be 0.77 +/- 0.06 mm and 0.96 +/- 0.06 mm, respectively, based on reconstructed photoacoustic images of phantoms containing individual human hairs. Finally, in vivo 3D photoacoustic sentinel lymph node mapping using methylene blue dye in a rat model is demonstrated.
Three-dimensional ultrasound palmprint recognition using curvature methods
NASA Astrophysics Data System (ADS)
Iula, Antonio; Nardiello, Donatella
2016-05-01
Palmprint recognition systems that use three-dimensional (3-D) information of the palm surface are the most recently explored techniques to overcome some two-dimensional palmprint difficulties. These techniques are based on light structural imaging. In this work, a 3-D ultrasound palmprint recognition system is proposed and evaluated. Volumetric images of a region of the human hand are obtained by moving an ultrasound linear array along its elevation direction and one by one acquiring a number of B-mode images, which are then grouped in a 3-D matrix. The acquisition time was contained in about 5 s. Much information that can be exploited for 3-D palmprint recognition is extracted from the ultrasound volumetric images, including palm curvature and other under-skin information as the depth of the various traits. The recognition procedure developed in this work is based on the analysis of the principal curvatures of palm surface, i.e., mean curvature image, Gaussian curvature image, and surface type. The proposed method is evaluated by performing verification and identification experiments. Preliminary results have shown that the proposed system exhibits an acceptable recognition rate. Further possible improvements of the proposed technique are finally highlighted and discussed.
Freehand three-dimensional ultrasound: implementation and applications
NASA Astrophysics Data System (ADS)
Sherebrin, S.; Fenster, Aaron; Rankin, Richard N.; Spence, David
1996-04-01
Three-dimensional ultrasound (3DUS) offers a valuable approach to many diagnostic imaging problems and provides a relatively low cost alternative to 3D imaging modalities such as MRI and CT. To obtain a 3DUS image, a clinical ultrasound scanner is used to produce a sequence of adjacent 'slices' of the region of interest, which are recorded and used to reconstruct a volume. The required location of each slice may be found either by a priori knowledge of the scan path (mechanized scanning) or by tracking the path of the transducer at scan time (freehand scanning). For some imaging applications the scan path is irregular, making mechanized scanning difficult or impossible. Some examples are: imaging vascular disease in the carotid arteries, joint imaging and obstetrics. We have developed a freehand 3DUS system that is capable of such imaging tasks. We used phantoms containing a wire and a 50% stenosed cylinder phantom to test our system for vascular applications. We found the mean error in locating any image plane to be less than 0.1 mm ((sigma) equals 0.05 mm), with minimal geometric distortion. The degree of stenosis of the phantom was measured from a reconstructed volume to be 52.6% ((sigma) equals 2%). We have started a clinical stenosis study and a pilot joint imaging study. Our clinical results indicate that measurement of stenosis in patients should be possible.
Automated quality assessment in three-dimensional breast ultrasound images.
Schwaab, Julia; Diez, Yago; Oliver, Arnau; Martí, Robert; van Zelst, Jan; Gubern-Mérida, Albert; Mourri, Ahmed Bensouda; Gregori, Johannes; Günther, Matthias
2016-04-01
Automated three-dimensional breast ultrasound (ABUS) is a valuable adjunct to x-ray mammography for breast cancer screening of women with dense breasts. High image quality is essential for proper diagnostics and computer-aided detection. We propose an automated image quality assessment system for ABUS images that detects artifacts at the time of acquisition. Therefore, we study three aspects that can corrupt ABUS images: the nipple position relative to the rest of the breast, the shadow caused by the nipple, and the shape of the breast contour on the image. Image processing and machine learning algorithms are combined to detect these artifacts based on 368 clinical ABUS images that have been rated manually by two experienced clinicians. At a specificity of 0.99, 55% of the images that were rated as low quality are detected by the proposed algorithms. The areas under the ROC curves of the single classifiers are 0.99 for the nipple position, 0.84 for the nipple shadow, and 0.89 for the breast contour shape. The proposed algorithms work fast and reliably, which makes them adequate for online evaluation of image quality during acquisition. The presented concept may be extended to further image modalities and quality aspects.
Three-dimensional flow vectors from rf ultrasound signals
NASA Astrophysics Data System (ADS)
Tuthill, Theresa A.; Rubin, Jonathan M.; Fowlkes, J. B.
2002-04-01
A new ultrasound technique for determining three-dimensional velocity vectors has been devised using radio frequency (RF) data from commercially available scanners. Applied to blood flow, this technique could prove useful for evaluating hemodynamics and detecting stenoses. Three orthogonal velocity vectors are computed from the RF signals of two steered beams from a single array. The in-plane velocities are determined using standard Doppler analysis, while the out-of-plane component is derived from the total velocity as computed from temporal decorrelation and the in-plane components. The technique was tested using contrast agent pumped through a flow tube. A GE Vingmed SystemV scanner with a 10 MHz linear array provided scans at beam steering angles of +/- 20 degree(s). Both Doppler velocities and temporal complex decorrelation were computed for each digitized voxel. Additional studies were done on a blood mimicking fluid and in vivo with a canine femoral artery. Vector plots were constructed to show flow for various transducer angles. Angle estimates were within 20 degree(s), and the mean error for the velocity amplitude was less than 15%. The in vivo results provided velocity estimates consistent with the literature. The proposed method, unlike current Doppler velocity measurement techniques, provides quantitative velocity information independent of transducer orientation.
Freehand three-dimensional ultrasound to assess semitendinosus muscle morphology.
Haberfehlner, Helga; Maas, Huub; Harlaar, Jaap; Becher, Jules G; Buizer, Annemieke I; Jaspers, Richard T
2016-10-01
In several neurological disorders and muscle injuries, morphological changes of the m. semitendinosus (ST) are presumed to contribute to movement limitations around the knee. Freehand three-dimensional (3D) ultrasound (US), using position tracking of two-dimensional US images to reconstruct a 3D voxel array, can be used to assess muscle morphology in vivo. The aims of this study were: (i) to introduce a newly developed 3D US protocol for ST; and (ii) provide a first comparison of morphological characteristics determined by 3D US with those measured on dissected cadaveric muscles. Morphological characteristics of ST (e.g. muscle belly length, tendon length, fascicle length and whole muscle volume, and volumes of both compartments) were assessed in six cadavers using a 3D US protocol. Subsequently, ST muscles were removed from the body to measure the same morphological characteristics. Mean differences between morphological characteristics measured by 3D US and after dissection were smaller than 10%. Intra-class correlation coefficients (ICCs) were higher than 0.75 for all variables except for the lengths of proximal fascicles (ICC = 0.58). Measurement of the volume of proximal compartment by 3D US was not feasible, due to low US image quality proximally. We conclude that the presented 3D US protocol allows for reasonably accurate measurements of key morphological characteristics of ST muscle.
NASA Astrophysics Data System (ADS)
Alqasemi, Umar; Li, Hai; Yuan, Guangqian; Aguirre, Andres; Zhu, Quing
2012-02-01
Co-registered Ultrasound and Photoacoustic images provide complimentary structure and functional information for cancer diagnosis and assessment of therapy response. In SPIE Photonics West 2011, we reported a system that acquires from 64 channels and displays up to 1 frame per second (fps) ultrasound pulse-echo images, 5 fps photoacoustic images, and 0.5 fps co-registered images. In this year, we report an upgraded system which acquires from 128 channels and displays up to 15 fps co-registered ultrasound and photoacoustic images limited by our laser pulse repetition rate. The system architecture is novel and it provides real-time co-registration of images, the ability of acquiring the channel RF data for both modalities, and the flexibility of adjusting every parameter involved in the imaging process for both modalities. The digital signal processor board is upgraded to an FPGA-based PCIe board that collects the data from the acquisition modules and transfers them to the PC memory at 2.5GT/s rate through an x8 DDR PCIe bus running at 100MHz clock frequency. The modules FPGA code is also upgraded to form a beam line in 90 microseconds and to communicate through ultrafast differential tracks with the PCIe board. Furthermore, the printed circuit board (PCB) design of the system was adjusted to provide a maximum of 80dB signal-to-noise ratio at 60dB gain, which is comparable to some commercial ultrasound machines. The real-time system allows capturing co-registered US/PAT images free of motion artifacts and also provides ultrafast dynamic information when a contrast agent is used. The system is built for clinical use to assist the diagnosis of ovarian cancer. However, the hardware is still under testing and evaluation stage, experimental and clinical results will be reported later.
Three-dimensional ultrasound imaging of the prostate
NASA Astrophysics Data System (ADS)
Fenster, Aaron; Downey, Donal B.
1999-05-01
Ultrasonography, a widely used imaging modality for the diagnosis and staging of many diseases, is an important cost- effective technique, however, technical improvements are necessary to realize its full potential. Two-dimensional viewing of 3D anatomy, using conventional ultrasonography, limits our ability to quantify and visualize most diseases, causing, in part, the reported variability in diagnosis and ultrasound guided therapy and surgery. This occurs because conventional ultrasound images are 2D, yet the anatomy is 3D; hence the diagnostician must integrate multiple images in his mind. This practice is inefficient, and may lead to operator variability and incorrect diagnoses. In addition, the 2D ultrasound image represents a single thin plane at some arbitrary angle in the body. It is difficult to localize and reproduce the image plane subsequently, making conventional ultrasonography unsatisfactory for follow-up studies and for monitoring therapy. Our efforts have focused on overcoming these deficiencies by developing 3D ultrasound imaging techniques that can acquire B-mode, color Doppler and power Doppler images. An inexpensive desktop computer is used to reconstruct the information in 3D, and then is also used for interactive viewing of the 3D images. We have used 3D ultrasound images for the diagnosis of prostate cancer, carotid disease, breast cancer and liver disease and for applications in obstetrics and gynecology. In addition, we have also used 3D ultrasonography for image-guided minimally invasive therapeutic applications of the prostate such as cryotherapy and brachytherapy.
Simultaneous three-dimensional laser-ultrasound and photoacoustic imaging
NASA Astrophysics Data System (ADS)
Wurzinger, Gerhild; Nuster, Robert; Schmitner, Nicole; Gratt, Sibylle; Paltauf, Günther
2013-06-01
A purely optical setup for simultaneous photoacoustic (PA) and laser-ultrasound (US) tomography is presented. It is shown that combined imaging can be achieved by using the same laser pulse for photoacoustic generation and for launching a broadband ultrasound pulse from an optically absorbing target. Detection of the laser-generated plane waves that have been scattered at the imaging object and of the photoacoustic signals emitted from the sample is done interferometrically. This way data for PA and US imaging are acquired within one single measurement. Distinction between the signals is possible due to their different times of flight. After data separation, image reconstruction is done using standard back-projection algorithms. The resolution of the setup was estimated and images of a zebra fish are shown, demonstrating the complementary information of the two imaging modalities.
Three-dimensional ultrasound imaging for diagnosis of urethrovaginal fistula.
Quiroz, Lieschen H; Shobeiri, S Abbas; Nihira, Mikio A
2010-08-01
We present a novel technique for visualization of a urethrovaginal fistula. A 52-year-old patient presented with persistent urinary incontinence, after having three mid-urethral sling procedures performed within the past year. The diagnosis of a urethrovaginal fistula was made by endovaginal 3-D endovaginal ultrasound and confirmed intraoperatively. We have described a novel technique that may benefit patients with urethrovaginal fistulas that are difficult to visualize.
Three-dimensional freehand ultrasound: image reconstruction and volume analysis.
Barry, C D; Allott, C P; John, N W; Mellor, P M; Arundel, P A; Thomson, D S; Waterton, J C
1997-01-01
A system is described that rapidly produces a regular 3-dimensional (3-D) data block suitable for processing by conventional image analysis and volume measurement software. The system uses electromagnetic spatial location of 2-dimensional (2-D) freehand-scanned ultrasound B-mode images, custom-built signal-conditioning hardware, UNIX-based computer processing and an efficient 3-D reconstruction algorithm. Utilisation of images from multiple angles of insonation, "compounding," reduces speckle contrast, improves structure coherence within the reconstructed grey-scale image and enhances the ability to detect structure boundaries and to segment and quantify features. Volume measurements using a series of water-filled latex and cylindrical foam rubber phantoms with volumes down to 0.7 mL show that a high degree of accuracy, precision and reproducibility can be obtained. Extension of the technique to handle in vivo data sets by allowing physiological criteria to be taken into account in selecting the images used for construction is also illustrated.
Quantitative three-dimensional transrectal ultrasound (TRUS) for prostate imaging
NASA Astrophysics Data System (ADS)
Pathak, Sayan D.; Aarnink, Rene G.; de la Rosette, Jean J.; Chalana, Vikram; Wijkstra, Hessel; Haynor, David R.; Debruyne, Frans M. J.; Kim, Yongmin
1998-06-01
With the number of men seeking medical care for prostate diseases rising steadily, the need of a fast and accurate prostate boundary detection and volume estimation tool is being increasingly experienced by the clinicians. Currently, these measurements are made manually, which results in a large examination time. A possible solution is to improve the efficiency by automating the boundary detection and volume estimation process with minimal involvement from the human experts. In this paper, we present an algorithm based on SNAKES to detect the boundaries. Our approach is to selectively enhance the contrast along the edges using an algorithm called sticks and integrate it with a SNAKES model. This integrated algorithm requires an initial curve for each ultrasound image to initiate the boundary detection process. We have used different schemes to generate the curves with a varying degree of automation and evaluated its effects on the algorithm performance. After the boundaries are identified, the prostate volume is calculated using planimetric volumetry. We have tested our algorithm on 6 different prostate volumes and compared the performance against the volumes manually measured by 3 experts. With the increase in the user inputs, the algorithm performance improved as expected. The results demonstrate that given an initial contour reasonably close to the prostate boundaries, the algorithm successfully delineates the prostate boundaries in an image, and the resulting volume measurements are in close agreement with those made by the human experts.
Three-dimensional ultrasound strain imaging of skeletal muscles
NASA Astrophysics Data System (ADS)
Gijsbertse, K.; Sprengers, A. M. J.; Nillesen, M. M.; Hansen, H. H. G.; Lopata, R. G. P.; Verdonschot, N.; de Korte, C. L.
2017-01-01
In this study, a multi-dimensional strain estimation method is presented to assess local relative deformation in three orthogonal directions in 3D space of skeletal muscles during voluntary contractions. A rigid translation and compressive deformation of a block phantom, that mimics muscle contraction, is used as experimental validation of the 3D technique and to compare its performance with respect to a 2D based technique. Axial, lateral and (in case of 3D) elevational displacements are estimated using a cross-correlation based displacement estimation algorithm. After transformation of the displacements to a Cartesian coordinate system, strain is derived using a least-squares strain estimator. The performance of both methods is compared by calculating the root-mean-squared error of the estimated displacements with the calculated theoretical displacements of the phantom experiments. We observe that the 3D technique delivers more accurate displacement estimations compared to the 2D technique, especially in the translation experiment where out-of-plane motion hampers the 2D technique. In vivo application of the 3D technique in the musculus vastus intermedius shows good resemblance between measured strain and the force pattern. Similarity of the strain curves of repetitive measurements indicates the reproducibility of voluntary contractions. These results indicate that 3D ultrasound is a valuable imaging tool to quantify complex tissue motion, especially when there is motion in three directions, which results in out-of-plane errors for 2D techniques.
Aguirre, Andres; Ardeshirpour, Yasaman; Sanders, Mary M; Brewer, Molly; Zhu, Quing
2011-02-01
Currently, there is no adequate technology to detect early stage ovarian cancers. Most of the cancers in the ovary are detected when the cancer has already metastasized to other parts of the body. As a result, ovarian cancer has the highest mortality of all gynecologic cancers with a 5-year survival rate of 30% or less. Thus, there is an urgent need to improve the current diagnostic techniques. Photoacoustic imaging (PAI) is an emerging modality with a great potential to assist ultrasound for detecting ovarian cancer noninvasively. In this article, we report the first study of coregistered ultrasound and PAI of 33 ex vivo human ovaries. An assessment of the photoacoustic images has revealed light absorption distribution in the ovary, which is directly related to the vasculature distribution and amount. Quantification of the light absorption levels in the ovary has indicated that, in the postmenopausal group, malignant ovaries showed significantly higher light absorption than normal ones (P = .0237). For these two groups, we have obtained a sensitivity of 83% and a specificity of 83%. This result suggests that PAI is a promising modality for improving ultrasound diagnosis of ovarian cancer.
Quantitative investigation of in vitro flow using three-dimensional colour Doppler ultrasound.
Guo, Z; Moreau, M; Rickey, D W; Picot, P A; Fenster, A
1995-01-01
A quantitative in vitro flow study was performed by using a three-dimensional colour Doppler imaging system. This system was based on a clinical ultrasound instrument with its transducer mounted on a motor-driven translation stage. A vascular and tissue-mimicking phantom containing two wall-less vessels, one normal and another stenotic, was used to quantify the measurement accuracy of the flow velocity and the flow field. Steady state flows, having Reynolds numbers ranging between 460 and 1300, were generated by a computer-controlled positive displacement pump. Effects of the parameter settings of the ultrasound instrument on results of the estimation of flow field were also studied. Experimental results show that our three-dimensional colour Doppler system's velocity accuracy was better than 7% of the Nyquist velocity and its spatial accuracy was better than 0.5 mm. The system showed a good correlation (r = 0.999) between the estimated and the true mean flow velocity, and a good correlation (r = 0.998) between the estimated maximum and the true mean flow velocity. This study is our first step toward validating the measurement of the three-dimensional velocity and wall shear stress distributions by using three-dimensional colour Doppler ultrasound
Controlling collagen fiber microstructure in three-dimensional hydrogels using ultrasound
Garvin, Kelley A.; VanderBurgh, Jacob; Hocking, Denise C.; Dalecki, Diane
2013-01-01
Type I collagen is the primary fibrillar component of the extracellular matrix, and functional properties of collagen arise from variations in fiber structure. This study investigated the ability of ultrasound to control collagen microstructure during hydrogel fabrication. Under appropriate conditions, ultrasound exposure of type I collagen during polymerization altered fiber microstructure. Scanning electron microscopy and second-harmonic generation microscopy revealed decreased collagen fiber diameters in response to ultrasound compared to sham-exposed samples. Results of mechanistic investigations were consistent with a thermal mechanism for the effects of ultrasound on collagen fiber structure. To control collagen microstructure site-specifically, a high frequency, 8.3-MHz, ultrasound beam was directed within the center of a large collagen sample producing dense networks of short, thin collagen fibrils within the central core of the gel and longer, thicker fibers outside the beam area. Fibroblasts seeded onto these gels migrated rapidly into small, circularly arranged aggregates only within the beam area, and clustered fibroblasts remodeled the central, ultrasound-exposed collagen fibrils into dense sheets. These investigations demonstrate the capability of ultrasound to spatially pattern various collagen microstructures within an engineered tissue noninvasively, thus enhancing the level of complexity of extracellular matrix microenvironments and cellular functions achievable within three-dimensional engineered tissues. PMID:23927189
NASA Astrophysics Data System (ADS)
Li, Hai; Kumavor, Patrick D.; Alqasemi, Umar; Zhu, Quing
2014-03-01
Human ovarian tissue features extracted from photoacoustic spectra data, beam envelopes and co-registered ultrasound and photoacoustic images are used to characterize cancerous vs. normal processes using a support vector machine (SVM) classifier. The centers of suspicious tumor areas are estimated from the Gaussian fitting of the mean Radon transforms of the photoacoustic image along 0 and 90 degrees. Normalized power spectra are calculated using the Fourier transform of the photoacoustic beamformed data across these suspicious areas, where the spectral slope and 0-MHz intercepts are extracted. Image statistics, envelope histogram fitting and maximum output of 6 composite filters of cancerous or normal patterns along with other previously used features are calculated to compose a total of 17 features. These features are extracted from 169 datasets of 19 ex vivo ovaries. Half of the cancerous and normal datasets are randomly chosen to train a SVM classifier with polynomial kernel and the remainder is used for testing. With 50 times data resampling, the SVM classifier, for the training group, gives 100% sensitivity and 100% specificity. For the testing group, it gives 89.68+/- 6.37% sensitivity and 93.16+/- 3.70% specificity. These results are superior to those obtained earlier by our group using features extracted from photoacoustic raw data or image statistics only.
NASA Astrophysics Data System (ADS)
Salehi, Hassan S.; Li, Hai; Merkulov, Alex; Kumavor, Patrick D.; Vavadi, Hamed; Sanders, Melinda; Kueck, Angela; Brewer, Molly A.; Zhu, Quing
2016-04-01
Most ovarian cancers are diagnosed at advanced stages due to the lack of efficacious screening techniques. Photoacoustic tomography (PAT) has a potential to image tumor angiogenesis and detect early neovascular changes of the ovary. We have developed a coregistered PAT and ultrasound (US) prototype system for real-time assessment of ovarian masses. Features extracted from PAT and US angular beams, envelopes, and images were input to a logistic classifier and a support vector machine (SVM) classifier to diagnose ovaries as benign or malignant. A total of 25 excised ovaries of 15 patients were studied and the logistic and SVM classifiers achieved sensitivities of 70.4 and 87.7%, and specificities of 95.6 and 97.9%, respectively. Furthermore, the ovaries of two patients were noninvasively imaged using the PAT/US system before surgical excision. By using five significant features and the logistic classifier, 12 out of 14 images (86% sensitivity) from a malignant ovarian mass and all 17 images (100% specificity) from a benign mass were accurately classified; the SVM correctly classified 10 out of 14 malignant images (71% sensitivity) and all 17 benign images (100% specificity). These initial results demonstrate the clinical potential of the PAT/US technique for ovarian cancer diagnosis.
NASA Astrophysics Data System (ADS)
Alqasemi, Umar; Kumavor, Patrick; Aguirre, Andres; Zhu, Quing
2012-12-01
Unique features and the underlining hypotheses of how these features may relate to the tumor physiology in coregistered ultrasound and photoacoustic images of ex vivo ovarian tissue are introduced. The images were first compressed with wavelet transform. The mean Radon transform of photoacoustic images was then computed and fitted with a Gaussian function to find the centroid of a suspicious area for shift-invariant recognition process. Twenty-four features were extracted from a training set by several methods, including Fourier transform, image statistics, and different composite filters. The features were chosen from more than 400 training images obtained from 33 ex vivo ovaries of 24 patients, and used to train three classifiers, including generalized linear model, neural network, and support vector machine (SVM). The SVM achieved the best training performance and was able to exclusively separate cancerous from non-cancerous cases with 100% sensitivity and specificity. At the end, the classifiers were used to test 95 new images obtained from 37 ovaries of 20 additional patients. The SVM classifier achieved 76.92% sensitivity and 95.12% specificity. Furthermore, if we assume that recognizing one image as a cancer is sufficient to consider an ovary as malignant, the SVM classifier achieves 100% sensitivity and 87.88% specificity.
Mézière, F; Juskova, P; Woittequand, J; Muller, M; Bossy, E; Boistel, Renaud; Malaquin, L; Derode, A
2016-02-01
In this paper, ultrasound measurements of 1:1 scale three-dimensional (3D) printed trabecular bone phantoms are reported. The micro-structure of a trabecular horse bone sample was obtained via synchrotron x-ray microtomography, converted to a 3D binary data set, and successfully 3D-printed at scale 1:1. Ultrasound through-transmission experiments were also performed through a highly anisotropic version of this structure, obtained by elongating the digitized structure prior to 3D printing. As in real anisotropic trabecular bone, both the fast and slow waves were observed. This illustrates the potential of stereolithography and the relevance of such bone phantoms for the study of ultrasound propagation in bone.
Three-dimensional ultrasound imaging of vessel wall for evaluating atherosclerosis risk and disease
NASA Astrophysics Data System (ADS)
Amin, Viren R.; Wang, Bo; Sonka, Milan; Lauer, Ronald M.
2002-04-01
This research aims at developing a three-dimensional (3D) ultrasound system for carotid and brachial artery scanning for evaluating vessel wall characteristics. In the long term, we seek to test hypothesis that the artery wall measurements of carotid intima-media-thickness and brachial flow mediated dilatation using 3D ultrasound data provide better repeatability than those derived from conventional 2D ultrasound scans. The approach is to implement a free-hand data acquisition scheme using conventional 2D medical ultrasound scanner, develop data processing algorithms for appropriately registering and displaying the volumetric ultrasound vessel scans, and develop techniques for measuring vessel wall characteristics. The system uses electromagnetic sensor mounted on the transducer to acquire position and orientation of each image slice as the transducer is moved freely to scan the area of interest. These non-parallel images are registered into a 3D dataset for reconstruction, segmentation, and measurements of the vessel wall structure. A simple calibration object is developed using a small stainless-steel sphere in a fixed position to perform coordinate transformations and pixel registration. A commercial 3D ultrasound tissue-mimicking phantom is used for assessment of freehand 3D data acquisition, calibration, registration, and visualization schemes. Early results of experimental carotid artery scans of volunteers are presented.
[Prenatal diagnosis of isolated otocefalia. Usefulness of three-dimensional ultrasound].
Escribano Abad, David; Arbués Gabarre, Juan; Gómez Montes, Enery; Puente Agueda, José Manuel; Herraiz García, Ignacio; Galindo Izquierdo, Alberto
2011-08-01
Otocephaly is a rare and lethal congenital malformation characterized by the presence of agnathia, microstomia, aglossia and synotia. Despite its frequent association with severe malformations, diagnosis in the few published cases is usually made at III trimester. In this case, three-dimensional ultrasound scan was performed in a Chinese primigravida with no remarkable personal nor familiar history since mandible was difficulty visualized with two-dimensional sonography at 21 weeks of gestation. Multiplanar and rendering mode showed the typical cervicofacial features of otocephaly without associated malformations. After parental counselling, they opted for termination of pregnancy and necropsy confirmed our prenatal findings. Our case shows the usefulness of three-dimensional ultrasound in assessing fetal cervicofacial pathology. Volumetric capture allows a delayed study of fetal anatomy and multiplanar mode offers the reconstruction of views whose achivement is difficult with conventional 2D ultrasound. Surface rendering provides excellent spatial vision and enables parents to understand the severity of the malformation thus helping with their decisions.
Three Dimensional Sheaf of Ultrasound Planes Reconstruction (SOUPR) of Ablated Volumes
Ingle, Atul; Varghese, Tomy
2014-01-01
This paper presents an algorithm for three dimensional reconstruction of tumor ablations using ultrasound shear wave imaging with electrode vibration elastography. Radiofrequency ultrasound data frames are acquired over imaging planes that form a subset of a sheaf of planes sharing a common axis of intersection. Shear wave velocity is estimated separately on each imaging plane using a piecewise linear function fitting technique with a fast optimization routine. An interpolation algorithm then computes velocity maps on a fine grid over a set of C-planes that are perpendicular to the axis of the sheaf. A full three dimensional rendering of the ablation can then be created from this stack of C-planes; hence the name “Sheaf Of Ultrasound Planes Reconstruction” or SOUPR. The algorithm is evaluated through numerical simulations and also using data acquired from a tissue mimicking phantom. Reconstruction quality is gauged using contrast and contrast-to-noise ratio measurements and changes in quality from using increasing number of planes in the sheaf are quantified. The highest contrast of 5 dB is seen between the stiffest and softest regions of the phantom. Under certain idealizing assumptions on the true shape of the ablation, good reconstruction quality while maintaining fast processing rate can be obtained with as few as 6 imaging planes suggesting that the method is suited for parsimonious data acquisitions with very few sparsely chosen imaging planes. PMID:24808405
Belachew, Johanna; Axelsson, Ove; Eurenius, Karin; Mulic-Lutvica, Ajlana
2015-01-01
The study objective was to improve ultrasonic diagnosis of retained placental tissue by measuring the volume of the uterine body and cavity using three-dimensional (3D) ultrasound. Twenty-five women who were to undergo surgical curettage due to suspected retained placental tissue were included. The volume of the uterine body and cavity was measured using the VOCAL imaging program. Twenty-one women had retained placental tissue histologically verified. Three of these had uterine volumes exceeding the largest volume observed in the normal puerperium. Seventeen of the 21 women had a uterine cavity volume exceeding the largest volume observed in the normal puerperium. In all 14 cases examined 28 days or more after delivery the cavity volume exceeded the largest volume observed in the normal puerperium. A large cavity volume estimated with 3D ultrasound is indicative of retained placental tissue. However, 3D ultrasound adds little or no diagnostic power compared to 2D ultrasound.
Three dimensional full-wave nonlinear acoustic simulations: Applications to ultrasound imaging
NASA Astrophysics Data System (ADS)
Pinton, Gianmarco
2015-10-01
Characterization of acoustic waves that propagate nonlinearly in an inhomogeneous medium has significant applications to diagnostic and therapeutic ultrasound. The generation of an ultrasound image of human tissue is based on the complex physics of acoustic wave propagation: diffraction, reflection, scattering, frequency dependent attenuation, and nonlinearity. The nonlinearity of wave propagation is used to the advantage of diagnostic scanners that use the harmonic components of the ultrasonic signal to improve the resolution and penetration of clinical scanners. One approach to simulating ultrasound images is to make approximations that can reduce the physics to systems that have a low computational cost. Here a maximalist approach is taken and the full three dimensional wave physics is simulated with finite differences. This paper demonstrates how finite difference simulations for the nonlinear acoustic wave equation can be used to generate physically realistic two and three dimensional ultrasound images anywhere in the body. A specific intercostal liver imaging scenario for two cases: with the ribs in place, and with the ribs removed. This configuration provides an imaging scenario that cannot be performed in vivo but that can test the influence of the ribs on image quality. Several imaging properties are studied, in particular the beamplots, the spatial coherence at the transducer surface, the distributed phase aberration, and the lesion detectability for imaging at the fundamental and harmonic frequencies. The results indicate, counterintuitively, that at the fundamental frequency the beamplot improves due to the apodization effect of the ribs but at the same time there is more degradation from reverberation clutter. At the harmonic frequency there is significantly less improvement in the beamplot and also significantly less degradation from reverberation. It is shown that even though simulating the full propagation physics is computationally challenging it
Three dimensional full-wave nonlinear acoustic simulations: Applications to ultrasound imaging
Pinton, Gianmarco
2015-10-28
Characterization of acoustic waves that propagate nonlinearly in an inhomogeneous medium has significant applications to diagnostic and therapeutic ultrasound. The generation of an ultrasound image of human tissue is based on the complex physics of acoustic wave propagation: diffraction, reflection, scattering, frequency dependent attenuation, and nonlinearity. The nonlinearity of wave propagation is used to the advantage of diagnostic scanners that use the harmonic components of the ultrasonic signal to improve the resolution and penetration of clinical scanners. One approach to simulating ultrasound images is to make approximations that can reduce the physics to systems that have a low computational cost. Here a maximalist approach is taken and the full three dimensional wave physics is simulated with finite differences. This paper demonstrates how finite difference simulations for the nonlinear acoustic wave equation can be used to generate physically realistic two and three dimensional ultrasound images anywhere in the body. A specific intercostal liver imaging scenario for two cases: with the ribs in place, and with the ribs removed. This configuration provides an imaging scenario that cannot be performed in vivo but that can test the influence of the ribs on image quality. Several imaging properties are studied, in particular the beamplots, the spatial coherence at the transducer surface, the distributed phase aberration, and the lesion detectability for imaging at the fundamental and harmonic frequencies. The results indicate, counterintuitively, that at the fundamental frequency the beamplot improves due to the apodization effect of the ribs but at the same time there is more degradation from reverberation clutter. At the harmonic frequency there is significantly less improvement in the beamplot and also significantly less degradation from reverberation. It is shown that even though simulating the full propagation physics is computationally challenging it
Wong, Philip; Muanza, Thierry; Reynard, Eric; Robert, Karine; Barker, Jennifer; Sultanem, Khalil
2011-01-01
Purpose: To evaluate the feasibility and usefulness of a three-dimensional ultrasound (3D-US) image-guided system in identifying and tracking the tumor bed (TB) for planning and daily localization before radiation delivery for breast cancer. Methods and Materials: Twenty breast cancer patients underwent two CT scans at the time of simulation and just before their boost. Three-dimensional ultrasound images were acquired immediately after the CT scans, to which the images were automatically fused. Three-dimensional ultrasound images were also acquired immediately before treatment. Spatial and temporal TB differences between CT and US were evaluated. Results: The TB was not visible on US and CT in 1 subject who had and 1 subject who had not received chemotherapy before whole-breast radiotherapy. The mean (SD) TB volume overlap was 78% (14%). The mean centroid position of the TB on CT vs. US differed by 0.1, 0.2, and 0.4 mm in the anterior-posterior, left-right, and superior-inferior directions. The mean (SD) absolute radial displacement of the TB on each fraction from the treatment plan was 10.8 (6.3) mm. Conclusions: The TB was well visualized by US for the majority of patients. Clinically insignificant differences in the displacements calculated by paired CT vs. paired US demonstrate the feasibility of using 3D-US. The present study suggests that a 10-mm planning target volume margin could result in undercoverage of the clinical target volumes in 50% of treatments. Multimodality planning and image-guided radiotherapy with US potentially offers an accurate and non-ionizing solution for the daily definition of the TB position during partial-breast irradiation and boost treatments.
Three-dimensional Ultrasound Image Presentation on an Immersive Projection System
NASA Astrophysics Data System (ADS)
Oshiro, Osamu; Imura, Masataka; Chihara, Kunihiro; Mikami, Taisei; Kitabatake, Akira
2002-05-01
This paper describes the presentation of a three-dimensional (3D) ultrasound heart image on an immersive projection system (IPS). A 3D image was reconstructed from B-mode images that were acquired by transesophagel echocardiography. The reconstructed 3D image was presented on the IPS and the observer can see a stereoscopic image. The immersive environment could present a large field of view and enables interactive browsing and free movement of an eye position. Therefore, our developed system has the potential to be used as a visual interface in future robot surgery.
GPU Based Real-time Instrument Tracking with Three Dimensional Ultrasound
Novotny, Paul M.; Stoll, Jeff A.; Vasilyev, Nikolay V.; Del Nido, Pedro J.; Dupont, Pierre E.; Howe, Robert D.
2009-01-01
Real-time three-dimensional ultrasound enables new intra-cardiac surgical procedures, but the distorted appearance of instruments in ultrasound poses a challenge to surgeons. This paper presents a detection technique that identifies the position of the instrument within the ultrasound volume. The algorithm uses a form of the generalized Radon transform to search for long straight objects in the ultrasound image, a feature characteristic of instruments and not found in cardiac tissue. When combined with passive markers placed on the instrument shaft, the full position and orientation of the instrument is found in 3D space. This detection technique is amenable to rapid execution on the current generation of personal computer graphics processor units (GPU). Our GPU implementation detected a surgical instrument in 31 ms, sufficient for real-time tracking at the 25 volumes per second rate of the ultrasound machine. A water tank experiment found instrument orientation errors of 1.1 degrees and tip position errors of less than 1.8 mm. Finally, an in vivo study demonstrated successful instrument tracking inside a beating porcine heart. PMID:17681483
Initial experience with stereoscopic visualization of three-dimensional ultrasound data in surgery.
Gronningsaeter, A; Lie, T; Kleven, A; Mørland, T; Langø, T; Unsgård, G; Myhre, H O; Mårvik, R
2000-11-01
Initial in vivo and in vitro experiments were performed to evaluate the feasibility of stereoscopically displaying three-dimensional (3D) ultrasound data from neurosurgery, laparoscopic surgery, and vascular surgery. Stereoscopic visualization was illustrated by four video sequences, which can be downloaded from http://www.us.unimed. sintef.no/. These sequences show a brain tumor, hepatic arteries in relation to the gallbladder, a model that mimics a neuroendoscope in a cyst, and a "flight" into model of an artery with an intima flap. The experiments indicate that stereoscopic display of ultrasound data is feasible when there is sufficient contrast between the objects of interest and the surrounding tissue. True 3D vision improves perception, thus enhancing the ability to understand complex anatomic structures such as irregular lesions and tortuous vessels.
Three-dimensional ultrasound guidance of autonomous robotic breast biopsy: feasibility study.
Liang, Kaicheng; Rogers, Albert J; Light, Edward D; von Allmen, Daniel; Smith, Stephen W
2010-01-01
Feasibility studies of autonomous robot biopsies in tissue have been conducted using real-time three-dimensional (3-D) ultrasound combined with simple thresholding algorithms. The robot first autonomously processed 3-D image volumes received from the ultrasound scanner to locate a metal rod target embedded in turkey breast tissue simulating a calcification, and in a separate experiment, the center of a water-filled void in the breast tissue simulating a cyst. In both experiments the robot then directed a needle to the desired target, with no user input required. Separate needle-touch experiments performed by the image-guided robot in a water tank yielded an rms error of 1.15 mm. (E-mail: kaicheng.liang@duke.edu).
Detection of congenital uterine malformation by using transvaginal three-dimensional ultrasound.
Yu, Li-Li; Zhang, Xuan; Zhang, Ting; Chen, Han-Rong; Wang, Ze-Hua
2014-10-01
This study assessed the clinical application of transvaginal three-dimensional ultrasound (3D TVUS) in the diagnosis of congenital uterine malformation. A retrospective study was performed on 62 patients with congenital uterine malformation confirmed hysteroscopically and/or laparoscopically. The patients were subjected to transvaginal two-dimensional ultrasound (2D TVUS) and 3D TVUS. The accuracy rate was compared between the two methods. The accuracy rate of 3D TVUS was (98.38%, 61/62), higher than that of 2D TVUS (80.65%, 50/62). 3D TVUS coronal plane imaging could demonstrate the internal shape of the endometrial cavity and the external contour of the uterine fundus. It allowed accurate measurement on the coronary plane, and could three-dimensionally show the image of cervical tube, thereby providing information for the diagnosis of some complex uterine malformation. 3D TVUS imaging can obtain comprehensive information of the uterus malformation, and it is superior to 2D TVUS for the diagnosis of congenital uterine malformations, especially complex uterine anomaly.
Three dimensional microbubble dynamics near a wall subject to high intensity ultrasound
NASA Astrophysics Data System (ADS)
Wang, Q. X.; Manmi, K.
2014-03-01
Dynamics of cavitation microbubbles due to high intensity ultrasound are associated with important applications in biomedical ultrasound, ultrasonic cleaning, and sonochemistry. Previous numerical studies on this phenomenon were for an axisymmetric configuration. In this paper, a computational model is developed to simulate the three dimensional dynamics of acoustic bubbles by using the boundary integral method. A bubble collapses much more violently subjected to high intensity ultrasound than when under normal constant ambient pressure. A few techniques are thus implemented to address the associated numerical challenge. In particular, a high quality mesh of the bubble surface is maintained by implementing a new hybrid approach of the Lagrangian method and elastic mesh technique. It avoids the numerical instabilities which occur at a sharp jet surface as well as generates a fine mesh needed at the jet surface. The model is validated against the Rayleigh-Plesset equation and an axisymmetric model. We then explore microbubble dynamics near a wall subjected to high intensity ultrasound propagating parallel to the wall, where the Bjerknes forces due to the ultrasound and the wall are perpendicular to each other. The bubble system absorbs the energy from the ultrasound and transforms the uniform momentum of the ultrasound parallel to the wall to the highly concentrated momentum of a high-speed liquid jet pointing to the wall. The liquid jet forms towards the end of the collapse phase with a significantly higher speed than without the presence of ultrasound. The jet direction depends mainly on the dimensionless standoff distance γ = s/Rmax of the bubble from the wall, where s is the distance between the wall and the bubble centre at inception and Rmax is the maximum bubble radius. The jet is approximately directed to the wall when γ is 1.5 or smaller and rotates to the direction of the ultrasound as γ increases. When γ is about 10 or larger, the wall effect is
Ultrasound-guided three-dimensional needle steering in biological tissue with curved surfaces.
Abayazid, Momen; Moreira, Pedro; Shahriari, Navid; Patil, Sachin; Alterovitz, Ron; Misra, Sarthak
2015-01-01
In this paper, we present a system capable of automatically steering a bevel-tipped flexible needle under ultrasound guidance toward a physical target while avoiding a physical obstacle embedded in gelatin phantoms and biological tissue with curved surfaces. An ultrasound pre-operative scan is performed for three-dimensional (3D) target localization and shape reconstruction. A controller based on implicit force control is developed to align the transducer with curved surfaces to assure the maximum contact area, and thus obtain an image of sufficient quality. We experimentally investigate the effect of needle insertion system parameters such as insertion speed, needle diameter and bevel angle on target motion to adjust the parameters that minimize the target motion during insertion. A fast sampling-based path planner is used to compute and periodically update a feasible path to the target that avoids obstacles. We present experimental results for target reconstruction and needle insertion procedures in gelatin-based phantoms and biological tissue. Mean targeting errors of 1.46±0.37 mm, 1.29±0.29 mm and 1.82±0.58 mm are obtained for phantoms with inclined, curved and combined (inclined and curved) surfaces, respectively, for insertion distance of 86-103 mm. The achieved targeting errors suggest that our approach is sufficient for targeting lesions of 3mm radius that can be detected using clinical ultrasound imaging systems.
Ultrasound-guided three-dimensional needle steering in biological tissue with curved surfaces
Abayazid, Momen; Moreira, Pedro; Shahriari, Navid; Patil, Sachin; Alterovitz, Ron; Misra, Sarthak
2015-01-01
In this paper, we present a system capable of automatically steering a bevel-tipped flexible needle under ultrasound guidance toward a physical target while avoiding a physical obstacle embedded in gelatin phantoms and biological tissue with curved surfaces. An ultrasound pre-operative scan is performed for three-dimensional (3D) target localization and shape reconstruction. A controller based on implicit force control is developed to align the transducer with curved surfaces to assure the maximum contact area, and thus obtain an image of sufficient quality. We experimentally investigate the effect of needle insertion system parameters such as insertion speed, needle diameter and bevel angle on target motion to adjust the parameters that minimize the target motion during insertion. A fast sampling-based path planner is used to compute and periodically update a feasible path to the target that avoids obstacles. We present experimental results for target reconstruction and needle insertion procedures in gelatin-based phantoms and biological tissue. Mean targeting errors of 1.46 ± 0.37 mm, 1.29 ± 0.29 mm and 1.82 ± 0.58 mm are obtained for phantoms with inclined, curved and combined (inclined and curved) surfaces, respectively, for insertion distance of 86–103 mm. The achieved targeting errors suggest that our approach is sufficient for targeting lesions of 3 mm radius that can be detected using clinical ultrasound imaging systems. PMID:25455165
Bossy, Emmanuel; Padilla, Frédéric; Peyrin, Françoise; Laugier, Pascal
2005-12-07
Three-dimensional numerical simulations of ultrasound transmission were performed through 31 trabecular bone samples measured by synchrotron microtomography. The synchrotron microtomography provided high resolution 3D mappings of bone structures, which were used as the input geometry in the simulation software developed in our laboratory. While absorption (i.e. the absorption of ultrasound through dissipative mechanisms) was not taken into account in the algorithm, the simulations reproduced major phenomena observed in real through-transmission experiments in trabecular bone. The simulated attenuation (i.e. the decrease of the transmitted ultrasonic energy) varies linearly with frequency in the MHz frequency range. Both the speed of sound (SOS) and the slope of the normalized frequency-dependent attenuation (nBUA) increase with the bone volume fraction. Twenty-five out of the thirty-one samples exhibited negative velocity dispersion. One sample was rotated to align the main orientation of the trabecular structure with the direction of ultrasonic propagation, leading to the observation of a fast and a slow wave. Coupling numerical simulation with real bone architecture therefore provides a powerful tool to investigate the physics of ultrasound propagation in trabecular structures. As an illustration, comparison between results obtained on bone modelled either as a fluid or a solid structure suggested the major role of mode conversion of the incident acoustic wave to shear waves in bone to explain the large contribution of scattering to the overall attenuation.
NASA Astrophysics Data System (ADS)
Bossy, Emmanuel; Padilla, Frédéric; Peyrin, Françoise; Laugier, Pascal
2005-12-01
Three-dimensional numerical simulations of ultrasound transmission were performed through 31 trabecular bone samples measured by synchrotron microtomography. The synchrotron microtomography provided high resolution 3D mappings of bone structures, which were used as the input geometry in the simulation software developed in our laboratory. While absorption (i.e. the absorption of ultrasound through dissipative mechanisms) was not taken into account in the algorithm, the simulations reproduced major phenomena observed in real through-transmission experiments in trabecular bone. The simulated attenuation (i.e. the decrease of the transmitted ultrasonic energy) varies linearly with frequency in the MHz frequency range. Both the speed of sound (SOS) and the slope of the normalized frequency-dependent attenuation (nBUA) increase with the bone volume fraction. Twenty-five out of the thirty-one samples exhibited negative velocity dispersion. One sample was rotated to align the main orientation of the trabecular structure with the direction of ultrasonic propagation, leading to the observation of a fast and a slow wave. Coupling numerical simulation with real bone architecture therefore provides a powerful tool to investigate the physics of ultrasound propagation in trabecular structures. As an illustration, comparison between results obtained on bone modelled either as a fluid or a solid structure suggested the major role of mode conversion of the incident acoustic wave to shear waves in bone to explain the large contribution of scattering to the overall attenuation.
Reconstruction of three-dimensional ultrasound images based on cyclic Savitzky-Golay filters
NASA Astrophysics Data System (ADS)
Toonkum, Pollakrit; Suwanwela, Nijasri C.; Chinrungrueng, Chedsada
2011-01-01
We present a new algorithm for reconstructing a three-dimensional (3-D) ultrasound image from a series of two-dimensional B-scan ultrasound slices acquired in the mechanical linear scanning framework. Unlike most existing 3-D ultrasound reconstruction algorithms, which have been developed and evaluated in the freehand scanning framework, the new algorithm has been designed to capitalize the regularity pattern of the mechanical linear scanning, where all the B-scan slices are precisely parallel and evenly spaced. The new reconstruction algorithm, referred to as the cyclic Savitzky-Golay (CSG) reconstruction filter, is an improvement on the original Savitzky-Golay filter in two respects: First, it is extended to accept a 3-D array of data as the filter input instead of a one-dimensional data sequence. Second, it incorporates the cyclic indicator function in its least-squares objective function so that the CSG algorithm can simultaneously perform both smoothing and interpolating tasks. The performance of the CSG reconstruction filter compared to that of most existing reconstruction algorithms in generating a 3-D synthetic test image and a clinical 3-D carotid artery bifurcation in the mechanical linear scanning framework are also reported.
Buck, T; Görge, G; Hunold, P; Erbel, R
1998-03-01
Two-dimensional (2D) transesophageal echocardiography (TEE) and 2D intravascular ultrasound (IVUS) imaging face their greatest limitation in visualizing aortic disease in patients. With the aid of three-dimensional (3D) image reconstruction, TEE and IVUS can potentially overcome this limitation but still provide only limited spatial appreciation in aortic disease because 3D imaging of the thoracic aorta requires a broader spatial visualization of the mediastinum than provided by both techniques. Moreover, for timely decision making about aortic disease TEE is limited by a large probe, which requires sedation. Therefore, we developed an approach called 3D lighthouse transesophageal echocardiography (LTEE) using a thin intravascular ultrasound catheter, which provides a full circumferential (360 degree) image and requires no sedation. The purpose of this study was to compare the feasibility and accuracy of 3D TEE, 3D IVUS, and 3D LTEE for obtaining spatial visualization of the thoracic aorta to detect aortic diseases in patients. 3D image datasets were obtained for 3D LTEE by a manual pullback of a 3.3 mm thick, 10 MHz intravascular ultrasound catheter positioned in the esophagus; for 3D TEE using a conventional 15 mm thick probe; and for 3D IVUS using a 2.6 mm thick, 20 MHz intravascular ultrasound catheter. In 12 consecutive patients, three with aortic dissection (two with type III, one with type I) and 11 with suspected artherosclerosis, we analyzed and compared spatial visualization of the thoracic aorta, 3D image quality, patient discomfort, and study time. Providing a 3D dataset of 360-degree tomographic images of the mediastinum, 3D LTEE was the only approach that allowed broad spatial visualization of the aortic arch (9 of 12 patients) with the detection of aortic dissection or atherosclerotic plaques. Spatial visualization of the aortic arch by 3D TEE was incomplete because of the relatively narrow 90-degree image sector. However, in other segments 3D image
Simulation of three-dimensional nonlinear fields of ultrasound therapeutic arrays
NASA Astrophysics Data System (ADS)
Yuldashev, P. V.; Khokhlova, V. A.
2011-05-01
A novel numerical model was developed to simulate three-dimensional nonlinear fields generated by high intensity focused ultrasound (HIFU) arrays. The model is based on the solution to the Westervelt equation; the developed algorithm makes it possible to model nonlinear pressure fields of periodic waves in the presence of shock fronts localized near the focus. The role of nonlinear effects in a focused beam of a two-dimensional array was investigated in a numerical experiment in water. The array consisting of 256 elements and intensity range on the array elements of up to 10 W/cm2 was considered. The results of simulations have shown that for characteristic intensity outputs of modern HIFU arrays, nonlinear effects play an important role and shock fronts develop in the pressure waveforms at the focus.
Image analysis of placental issues using three-dimensional ultrasound and color power doppler
NASA Astrophysics Data System (ADS)
Wang, Qi; Cheng, Qiong; Liu, J. G.
2007-12-01
With the development of birthing-process medical science, and insurance requirement of prepotency, the ultrasound technique is widely used in the application of obstetrics realm, especially on the monitoring of embryo's growth. In the recent decade, the introduction of high resolution three-dimensional ultrasonic and color power Doppler scanner provides a much more direct, sensitive, forerunner method for the monitoring of embryo and gravida's prediction. A novel method that depends on examining images of vasculature of placenta to determine the growth of embryo is introduced in this paper. First, get a set of placenta vascularity images of the pregnant woman, taken by Color Doppler Ultrasonic Scanner, then mark some points in these images, where we get a section image, thus we can observe the internal blood vessel distribution at those points. This method provides an efficient tool for doctors.
NASA Technical Reports Server (NTRS)
Shekhar, R.; Cothren, R. M.; Vince, D. G.; Chandra, S.; Thomas, J. D.; Cornhill, J. F.
1999-01-01
Intravascular ultrasound (IVUS) provides exact anatomy of arteries, allowing accurate quantitative analysis. Automated segmentation of IVUS images is a prerequisite for routine quantitative analyses. We present a new three-dimensional (3D) segmentation technique, called active surface segmentation, which detects luminal and adventitial borders in IVUS pullback examinations of coronary arteries. The technique was validated against expert tracings by computing correlation coefficients (range 0.83-0.97) and William's index values (range 0.37-0.66). The technique was statistically accurate, robust to image artifacts, and capable of segmenting a large number of images rapidly. Active surface segmentation enabled geometrically accurate 3D reconstruction and visualization of coronary arteries and volumetric measurements.
Computational synthesis of ultrasound breast images from a three-dimensional anatomical model
NASA Astrophysics Data System (ADS)
Shen, Yi-Ting; Lacefield, James C.
2005-04-01
A three-dimensional breast anatomy model has been implemented using spline surfaces and fractal structures to represent the architecture of the lactiferous ducts, mammary fat lobules, skin, and supporting connective tissues. The model randomly varies user-specified structural parameters to provide an unlimited number of realizations of the gross anatomy. Cross-sectional views extracted by slicing through a realization of the model are input to a two-dimensional k-space (i.e., spatial frequency domain) ultrasound propagation simulator. The k-space simulator iterates pressure and particle velocity fields in 30-ns steps to compute scattering from the structures defined by the anatomical model and small random variations in compressibility that are added to generate speckle. A synthetic aperture method is employed to simulate B-mode imaging with a 5 MHz, 192-element linear array operated using multiple transmit focal zones and dynamic receive focusing. Simulated images of random-scattering phantoms possess approximately Rayleigh speckle statistics. The anatomical model is expected to yield images with speckle statistics comparable to clinical breast images. The long-term objectives of these simulations are to investigate sources of focus aberration in ultrasound breast imaging and the impact of aberration on cancer detection. [Work supported by an NSERC Discovery Grant.
NASA Astrophysics Data System (ADS)
Awad, Joseph; Krasinski, Adam; Spence, David; Parraga, Grace; Fenster, Aaron
2010-03-01
Carotid atherosclerosis is the major cause of ischemic stroke, a leading cause of death and disability. This is driving the development of image analysis methods to quantitatively evaluate local arterial effects of potential treatments of carotid disease. Here we investigate the use of novel texture analysis tools to detect potential changes in the carotid arteries after statin therapy. Three-dimensional (3D) carotid ultrasound images were acquired from the left and right carotid arteries of 35 subjects (16 treated with 80 mg atorvastatin and 19 treated with placebo) at baseline and after 3 months of treatment. Two-hundred and seventy texture features were extracted from 3D ultrasound carotid artery images. These images previously had their vessel walls (VW) manually segmented. Highly ranked individual texture features were selected and compared to the VW volume (VWV) change using 3 measures: distance between classes, Wilcoxon rank sum test, and accuracy of the classifiers. Six classifiers were used. Using texture feature (L7R7) increases the average accuracy and area under the ROC curve to 74.4% and 0.72 respectively compared to 57.2% and 0.61 using VWV change. Thus, the results demonstrate that texture features are more sensitive in detecting drug effects on the carotid vessel wall than VWV change.
Jo, Yun Sung; Son, Hyun Joo; Jang, Dong Gyu; Kim, Narinay; Lee, Guisera
2011-01-01
A 29-year-old pregnant woman with parity 0-0-0-0 was diagnosed with monoamniotic twin pregnancy discordant for anencephaly at 14 weeks gestation. Umbilical cord entanglement, which is an important cause of fetal death in monoamniotic twins, was confirmed by three-dimensional ultrasound. Cesarean section was performed at 34 weeks of gestation, and the normal newborn infant was discharged without any complications. We report a case of monoamniotic twin pregnancy discordant for anencephaly and diagnosed with cord entanglement by three-dimensional ultrasound at 14 weeks of gestation, and now report it along with a literature review.
Niknejadi, Maryam; Akhbari, Farnaz; Niknejad, Fatemeh; Khalili, Gholamreza; Shiva, Marzieh
2014-01-01
Background: Traditionally, septate uterus was diagnosed with invasive method like hysterosalpingography and hysteroscopy. Nowadays transvaginal ultrasonography was reported to be a sensitive tool for detection of septate uterus too. Objective: The objective of the present study was to evaluate the application of two dimensional ultrasound (2-DUS) and real time three dimensional ultrasound (3-DUS) in differentiating various type of septated uterus. Hysteroscopy confirmation was assigned as the gold standard. Materials and Methods: This retrospective study was performed among 215 infertile women with suspected septate uterus from October 2008 to July 2012. An inclusion criterion was septated uterus based on HSG or experiencing abortion, preterm labor, or recurrent IVF failure. Fusion anomalies were excluded from the study (unicornuate, bicornuate and didelphys anomalies). The results of 3D and 2D sonographies were compared, while they were confirmed by hysteroscopy result in detection of septated uterus. Kappa index for agreement between 2DUS and hysteroscopy, as well as 3-DUS and hysteroscopy in detection of septate uterus was carried out. By receiver operating characteristic (ROC) curve, cut off points for predicting the kind of anomalies were proposed. Results: The women were evaluated by 2-DUS (n=89) and (II) 3-DUS (n=126). All women underwent hysteroscopy, following 2-DUS and 3-DUS at the same or subsequent cycle. The results of kappa (K) index were 0.575 and 0.291 for 3-DUS and hysteroscopy, as well as 2-DUS and hysteroscopy, respectively. Also, the cutoff points were 27% for arcuate and subseptate, and 35% for differentiating septate and subseptate. Conclusion: Real time 3-DUS has better ability for visualization both uterine cavity and the fundal uterine, so it has higher agreement in detection of septate uterus than 2-DUS. PMID:25408704
Direct three-dimensional ultrasound-to-video registration using photoacoustic markers
NASA Astrophysics Data System (ADS)
Cheng, Alexis; Kang, Jin U.; Taylor, Russell H.; Boctor, Emad M.
2013-06-01
Modern surgical procedures often have a fusion of video and other imaging modalities to provide the surgeon with information support. This requires interventional guidance equipment and surgical navigation systems to register different tools and devices together, such as stereoscopic endoscopes and ultrasound (US) transducers. In this work, the focus is specifically on the registration between these two devices. Electromagnetic and optical trackers are typically used to acquire this registration, but they have various drawbacks typically leading to target registration errors (TRE) of approximately 3 mm. We introduce photoacoustic markers for direct three-dimensional (3-D) US-to-video registration. The feasibility of this method was demonstrated on synthetic and ex vivo porcine liver, kidney, and fat phantoms with an air-coupled laser and a motorized 3-D US probe. The resulting TRE for each experiment ranged from 380 to 850 μm with standard deviations ranging from 150 to 450 μm. We also discuss a roadmap to bring this system into the surgical setting and possible challenges along the way.
Inglis, Scott; Christie, Derek; Plevris, John N
2011-11-01
This study details the development and evaluation of a freehand radial three-dimensional endoscopic ultrasound (3D-EUS) technique for use in the upper gastro-intestinal tract. It comprised of a commercial EUS system, a custom acquisition system to simultaneous acquire radial B-mode images and corresponding incremental changes in position of the scope as it was withdrawn and a custom 3D-EUS package written in Matlab™, to reconstruct and analyse the volume. This technique was evaluated using an EUS phantom with embedded objects of known dimensions and volumes and with clinical images acquired during routine cancer staging. For the phantom measurements, average Z-dimensional error was <1% and volume errors were 1.4% (volume(1) = 48930 mm(3)) and 4.5% (volume(2) = 5100 mm(3)). Application of this technique to EUS acquired clinical images produced excellent characterisation of oesophageal structures and accurate dimension and volume measurements. It also enabled the endoscopist to review "off-line" the EUS examination in case important information was missed.
Sridharan, Anush; Eisenbrey, John R.; Liu, Ji-Bin; Machado, Priscilla; Halldorsdottir, Valgerdur G.; Dave, Jaydev K.; Zhao, Hongjia; He, Yu; Park, Suhyun; Dianis, Scott; Wallace, Kirk; Thomenius, Kai E.; Forsberg, Flemming
2013-01-01
Objectives The ability to estimate tissue perfusion (in mL/min/g) in vivo using contrast-enhanced three-dimensional (3D) harmonic and subharmonic ultrasound imaging was investigated. Materials and Methods A Logiq 9 scanner (GE Healthcare, Milwaukee, WI) equipped with a 4D10L probe was modified to perform 3D harmonic imaging (HI; ftransmit = 5 MHz and freceive = 10 MHz) and subharmonic imaging (SHI; ftransmit= 5.8 MHz and freceive= 2.9 MHz). In vivo imaging was performed in the lower pole of both kidneys in five open-abdomen canines after injection of the ultrasound contrast agent (UCA) Definity (Lantheus Medical Imaging, N Billerica, MA). The canines received a 5 μL/kg bolus injection of Definity for HI and a 20 μL/kg bolus for SHI in triplicate for each kidney. Ultrasound data acquisition was started just prior to injection of UCA (in order to capture the wash-in) and continued until washout. A microvascular staining technique based on stable (non-radioactive) isotope-labeled microspheres (Biophysics Assay Laboratory Inc, Worcester, MA) was used to quantify the degree of perfusion in each kidney (the reference standard). Ligating a surgically exposed branch of the renal arteries induced lower perfusion rates. This was followed by additional contrast-enhanced imaging and microsphere injections to measure post-ligation perfusion. Slice data were extracted from the 3D ultrasound volumes and used to generate time-intensity curves off-line in the regions corresponding to the tissue samples used for microvascular staining. The mid-line plane was also selected from the 3D volume (as a quasi-2D image) and compared to the 3D imaging modes. Perfusion was estimated from the initial slope of the fractional blood volume uptake (for both HI and SHI) and compared to the reference standard using linear regression analysis. Results Both 3D HI and SHI were able to provide visualization of flow and, thus, perfusion in the kidneys. However, SHI provided near complete tissue
Cresswell, Andrew G.; Lichtwark, Glen A.
2016-01-01
Background. Muscles not only shorten during contraction to perform mechanical work, but they also bulge radially because of the isovolumetric constraint on muscle fibres. Muscle bulging may have important implications for muscle performance, however quantifying three-dimensional (3D) muscle shape changes in human muscle is problematic because of difficulties with sustaining contractions for the duration of an in vivo scan. Although two-dimensional ultrasound imaging is useful for measuring local muscle deformations, assumptions must be made about global muscle shape changes, which could lead to errors in fully understanding the mechanical behaviour of muscle and its surrounding connective tissues, such as aponeurosis. Therefore, the aims of this investigation were (a) to determine the intra-session reliability of a novel 3D ultrasound (3DUS) imaging method for measuring in vivo human muscle and aponeurosis deformations and (b) to examine how contraction intensity influences in vivo human muscle and aponeurosis strains during isometric contractions. Methods. Participants (n = 12) were seated in a reclined position with their left knee extended and ankle at 90° and performed isometric dorsiflexion contractions up to 50% of maximal voluntary contraction. 3DUS scans of the tibialis anterior (TA) muscle belly were performed during the contractions and at rest to assess muscle volume, muscle length, muscle cross-sectional area, muscle thickness and width, fascicle length and pennation angle, and central aponeurosis width and length. The 3DUS scan involved synchronous B-mode ultrasound imaging and 3D motion capture of the position and orientation of the ultrasound transducer, while successive cross-sectional slices were captured by sweeping the transducer along the muscle. Results. 3DUS was shown to be highly reliable across measures of muscle volume, muscle length, fascicle length and central aponeurosis length (ICC ≥ 0.98, CV < 1%). The TA remained isovolumetric
Vascularization of Three-Dimensional Collagen Hydrogels Using Ultrasound Standing Wave Fields
Garvin, Kelley A.; Dalecki, Diane; Hocking, Denise C.
2011-01-01
The successful fabrication of large, three-dimensional (3D) tissues and organs in vitro requires the rapid development of a vascular network to maintain cell viability and tissue function. In this study, we utilized an application of ultrasound standing wave field (USWF) technology to vascularize 3D, collagen-based hydrogels in vitro. Acoustic radiation forces associated with USWF were used to non-invasively organize human endothelial cells into distinct, multicellular planar bands within 3D collagen gels. The formation and maturation of capillary-like endothelial cell sprouts was monitored over time and compared to sham-exposed collagen constructs which were characterized by a homogeneous cell distribution. USWF10 induced cell banding accelerated the formation and elongation of capillary-like sprouts, promoted collagen fiber alignment, and resulted in the maturation of endothelial cell sprouts into lumen-containing, anastomosing networks found throughout the entire volume of the collagen gel. USWF-induced endothelial cell networks contained large, arteriole-sized lumen areas that branched into smaller, capillary-sized structures indicating the development of vascular tree-like networks. In contrast, sprout formation was delayed in sham-exposed collagen gels, and endothelial cell networks were absent from sham gel centers and failed to develop into the vascular tree-like structures found in USWF-exposed constructs. Our results demonstrate that USWF technology leads to rapid and extensive vascularization of 3D collagen-based engineered tissue and therefore, provides a new strategy to vascularize engineered tissues in vitro. PMID:21924816
Dunham, R; Wolstenhulme, S; Wilson, J
2014-01-01
The aims of the study were to evaluate whether three-dimensional transvaginal ultrasound (3D TV US) is superior to two-dimensional transvaginal ultrasound (2D TV US) at visualising intrauterine devices and determining their position. This prospective study included 52 participants with an intrauterine device fitted, who underwent 2D TV US and 3D TV US. 2D TV US and 3D-reconstructed coronal images were reviewed by two gynaecological radiologists to assess ease of visualisation and position of the intrauterine devices. Statistical analysis was performed using Wilcoxon signed-rank, McNemar and Chi-squared tests. The inter-observer agreement was measured using Cohen’s Kappa. Intrauterine device visualisation scores were significantly higher with 2D TV US compared with 3D TV US (Radiologist 1 p = <0.001, Radiologist 2 p = 0.007). A significant number of T-arms appeared to perforate into the adjacent myometrium on the 3D-reconstructed coronal image, but were normal on the 2D images (Radiologist 1 p = <0.001, Radiologist 2 p = 0.008). Radiologist 1 found 19 perforated T-arms on 3D TV US compared with four on 2D TV US. Radiologist 2 found 13 perforated T-arms on 3D TV US compared with five on 2D TV US. Both radiologists agreed on the positions of the intrauterine devices substantially with 3D TV US (Kappa = 0.69) and moderately with 2D TV US (Kappa = 0.55). The 3D TV US did not visualise an intrauterine device better than 2D TV US. The 3D-reconstructed coronal image of the uterus can reliably display cases of T-arm perforation into the adjacent myometrium, which could be missed on 2D TV US images. The 3D TV US should be used in addition to 2D TV US in all cases where an intrauterine device is under evaluation. PMID:27433211
Wang, Huaijun; Kaneko, Osamu F.; Tian, Lu; Hristov, Dimitre; Willmann, Jürgen K.
2015-01-01
Objectives We sought to assess the feasibility and reproducibility of three-dimensional (3D) ultrasound molecular imaging (USMI) of vascular endothelial growth factor receptor 2 (VEGFR2) expression in tumor angiogenesis using a clinical matrix array transducer and a clinical grade VEGFR2-targeted contrast agent in a murine model of human colon cancer. Materials and Methods Animal studies were approved by the Institutional Administrative Panel on Laboratory Animal Care. Mice with human colon cancer xenografts (n=33) were imaged with a clinical ultrasound system and transducer (Philips iU22; X6-1) following intravenous injection of either clinical grade VEGFR2-targeted microbubbles (MBVEGFR2) or non-targeted control microbubbles (MBControl). Nineteen mice were scanned twice to assess imaging reproducibility. Fourteen mice were scanned both before and 24h after treatment with either bevacizumab (n=7) or saline only (n=7). 3D USMI datasets were retrospectively reconstructed into multiple consecutive 1-mm thick USMI data sets to simulate 2D imaging. Vascular VEGFR2 expression was assessed ex vivo using immunofluorescence. Results 3D USMI was highly reproducible using both MBVEGFR2 and MBControl (ICC=0.83). VEGFR2-targeted USMI signal significantly (P=0.02) decreased by 57% following anti-angiogenic treatment compared to the control group, which correlated well with ex vivo VEGFR2 expression on immunofluorescence (rho=0.93, P=0.003). If only central 1-mm tumor planes were analyzed to assess anti-angiogenic treatment response, the USMI signal change was significantly (P=0.006) overestimated by an average of 27% (range, 2–73%) compared to 3D USMI. Conclusions 3D USMI is feasible and highly reproducible and allows accurate assessment and monitoring of VEGFR2 expression in tumor angiogenesis in a murine model of human colon cancer. PMID:25575176
NASA Astrophysics Data System (ADS)
Dovlo, Edem; Lashkari, Bahman; Mandelis, Andreas
2016-03-01
Frequency-domain photoacoustic radar (FD-PAR) imaging of absorbers in turbid media and their comparison and/or validation as well as co-registration with their corresponding ultrasound (US) images are demonstrated in this paper. Also presented are the FD-PAR tomography and the effects of reducing the number of scan lines (or angles) on image quality, resolution, and contrast. The FD-PAR modality uses intensity-modulated (coded) continuous wave laser sources driven by frequency-swept (chirp) waveforms. The spatial cross-correlation function between the PA response and the reference signal used for laser source modulation produces the reconstructed image. Live animal testing is demonstrated, and images of comparable signal-to-noise ratio, contrast, and spatial resolution were obtained. Various image improvement techniques to further reduce absorber spread and artifacts in the images such as normalization, filtering, and amplification were also investigated. The co-registered image produced from the combined US and PA images provides more information than both images independently. The significance of this work lies in the fact that achieving PA imaging functionality on a commercial ultrasound instrument could accelerate its clinical acceptance and use. This work is aimed at functional PA imaging of small animals in vivo.
Dovlo, Edem; Lashkari, Bahman; Mandelis, Andreas; Shi, Wei; Liu, Fei-Fei
2015-03-01
Co-registered ultrasound (US) and frequency-domain photoacoustic radar (FD-PAR) imaging is reported for the first time in this paper. The merits of ultrasound and cross-correlation (radar) frequency-domain photoacoustic imaging are leveraged for accurate tumor detection. Commercial US imagers possess sophisticated, optimized software for rapid image acquisition that could dramatically speed-up PA imaging. The PAR image generated from the amplitude of the cross-correlation between detected and input signals was filtered by the standard deviation (SD) of the phase of the correlation signal, resulting in strong improvement of image spatial resolution, signal-to-noise ratio (SNR) and contrast. Application of phase-mediated image improvement is illustrated by imaging a cancer cell-injected mouse. A 14-15 dB SNR gain was recorded for the phase-filtered image compared to the amplitude and phase independently, while ~340 μm spatial resolution was seen for the phase PAR image compared to ~840 μm for the amplitude image.
Dovlo, Edem; Lashkari, Bahman; Mandelis, Andreas; Shi, Wei; Liu, Fei-Fei
2015-01-01
Co-registered ultrasound (US) and frequency-domain photoacoustic radar (FD-PAR) imaging is reported for the first time in this paper. The merits of ultrasound and cross-correlation (radar) frequency-domain photoacoustic imaging are leveraged for accurate tumor detection. Commercial US imagers possess sophisticated, optimized software for rapid image acquisition that could dramatically speed-up PA imaging. The PAR image generated from the amplitude of the cross-correlation between detected and input signals was filtered by the standard deviation (SD) of the phase of the correlation signal, resulting in strong improvement of image spatial resolution, signal-to-noise ratio (SNR) and contrast. Application of phase-mediated image improvement is illustrated by imaging a cancer cell-injected mouse. A 14–15 dB SNR gain was recorded for the phase-filtered image compared to the amplitude and phase independently, while ~340 μm spatial resolution was seen for the phase PAR image compared to ~840 μm for the amplitude image. PMID:25798321
NASA Astrophysics Data System (ADS)
Ermilov, Sergey A.; Fronheiser, Matthew P.; Nadvoretsky, Vyacheslav; Brecht, Hans-Peter; Su, Richard; Conjusteau, André; Mehta, Ketan; Otto, Pamela; Oraevsky, Alexander A.
2010-02-01
We present results from a clinical case study on imaging breast cancer using a real-time interleaved two laser optoacoustic imaging system co-registered with ultrasound. The present version of Laser Optoacoustic Ultrasonic Imaging System (LOUIS) utilizes a commercial linear ultrasonic transducer array, which has been modified to include two parallel rectangular optical bundles, to operate in both ultrasonic (US) and optoacoustic (OA) modes. In OA mode, the images from two optical wavelengths (755 nm and 1064 nm) that provide opposite contrasts for optical absorption of oxygenated vs deoxygenated blood can be displayed simultaneously at a maximum rate of 20 Hz. The real-time aspect of the system permits probe manipulations that can assist in the detection of the lesion. The results show the ability of LOUIS to co-register regions of high absorption seen in OA images with US images collected at the same location with the dual modality probe. The dual wavelength results demonstrate that LOUIS can potentially provide breast cancer diagnostics based on different intensities of OA images of the lesion obtained at 755 nm and 1064 nm. We also present new data processing based on deconvolution of the LOUIS impulse response that helps recover original optoacoustic pressure profiles. Finally, we demonstrate the image analysis tool that provides automatic detection of the tumor boundary and quantitative metrics of the optoacoustic image quality. Using a blood vessel phantom submerged in a tissue-like milky background solution we show that the image contrast is minimally affected by the phantom distance from the LOUIS probe until about 60-65 mm. We suggest using the image contrast for quantitative assessment of an OA image of a breast lesion, as a part of the breast cancer diagnostics procedure.
Manual planimetric measurement of carotid plaque volume using three-dimensional ultrasound imaging
Landry, Anthony; Ainsworth, Craig; Blake, Chris; Spence, J. David; Fenster, Aaron
2007-04-15
We investigated the utility of three manual planimetric methods to quantify carotid plaque volume. A single observer measured 15 individual plaques from 15 three-dimensional (3D) ultrasound (3D US) images of patients ten times each using three different planimetric approaches. Individual plaque volumes were measured (range: 32.6-597.1 mm{sup 3}) using a standard planimetric approach (M1) whereby a plaque end was identified and sequential contours were measured. The same plaques were measured using a second approach (M2), whereby plaque ends were first identified and the 3D US image of the plaque was then subdivided into equal intervals. A third method (M3) was used to measure total plaque burden (range: 165.1-1080.0 mm{sup 3}) in a region ({+-}1.5 cm) relative to the carotid bifurcation. M1 systematically underestimated individual plaque volume compared to M2 (V{sub 2}=V{sub 1}+14.0 mm{sup 3}, r=0.99, p=0.006) due to a difference in the mean plaque length measured. Coefficients of variance (CV) for M1 and M2 decrease with increasing plaque volume, with M2 results less than M1. Root mean square difference between experimental and theoretical CV for M2 was 3.2%. The standard deviation in the identification of the transverse location of the carotid bifurcation was 0.56 mm. CVs for plaque burden measured using M3 ranged from 1.2% to 7.6% and were less than CVs determined for individual plaque volumes of the same volume. The utility of M3 was demonstrated by measuring carotid plaque burden and volume change over a period of 3 months in three patients. In conclusion, M2 was determined to be a more superior measurement technique than M1 to measure individual plaque volume. Furthermore, we demonstrated the utility of M3 to quantify regional plaque burden and to quantify change in plaque volume.
Bénard, Menno R; Harlaar, Jaap; Becher, Jules G; Huijing, Peter A; Jaspers, Richard T
2011-09-01
During development, muscle growth is usually finely adapted to meet functional demands in daily activities. However, how muscle geometry changes in typically developing children and how these changes are related to functional and mechanical properties is largely unknown. In rodents, longitudinal growth of the pennate m. gastrocnemius medialis (GM) has been shown to occur mainly by an increase in physiological cross-sectional area and less by an increase in fibre length. Therefore, we aimed to: (i) determine how geometry of GM changes in healthy children between the ages of 5 and 12 years, (ii) test whether GM geometry in these children is affected by gender, (iii) compare normalized growth of GM geometry in children with that in rats at similar normalized ages, and (iv) investigate how GM geometry in children relates to range of motion of angular foot movement at a given moment. Thirty children (16 females, 14 males) participated in the study. Moment-angle data were collected over a range of angles by rotating the foot from plantar flexion to dorsal flexion at standardized moments. GM geometry in the mid-longitudinal plane was measured using three-dimensional ultrasound imaging. This geometry was compared with that of GM geometry in rats. During growth from 5 to 12 years of age, the mean neutral footplate angle (0 Nm) occurred at -5° (SD 7°) and was not a function of age. Measured at standardized moments (4 Nm), footplate angles towards plantar flexion and dorsal flexion decreased by 25 and 40%, respectively. In both rats and children, GM muscle length increased proportionally with tibia length. In children, the length component of the physiological cross-sectional area and fascicle length increased by 7 and 5% per year, respectively. Fascicle angle did not change over the age range measured. In children, the Achilles tendon length increased by 6% per year. GM geometry was not affected by gender. We conclude that, whereas the length of GM in rat develops mainly
NASA Astrophysics Data System (ADS)
van Es, Peter; Vlieg, Redmar C.; Biswas, Samir K.; Hondebrink, Erwin; van Hespen, Johan C. G.; Moens, Hein B. J.; Steenbergen, Wiendelt; Manohar, Srirang
2015-07-01
Photoacoustic (PA) or optoacoustic (OA) imaging combines the high (blood) contrast to light with the high-resolution of ultrasound. The method can visualize vascularization deep inside tissue. Of late there is interest in PA imaging of synovial joints which are expected to be associated with increased vascularization in the event of rheumatoid arthritis (RA). We here describe our approach in investigating the application of the PA technique in arthritis. We are developing a CT-geometry version PA finger imager, intended for early clinical assessment of the method. The imager uses two curved array ultrasound detectors each with 64 elements with central frequencies 1.5 and 7.5 MHz respectively, stacked above each other. Both cover approximately 180 degrees of the circle. Illumination is provided with a multiple of optical fiber bundles coupled to a laser-OPO system. Ultrasound imaging is also possible with the system, since the curved arrays are each provided with 12 or 8 ultrasound pulsers. We have investigated systematically imaging of finger vasculature in healthy volunteers using an earlier laboratory prototype. In this paper we present finger imaging results of a patient diagnosed with rheumatoid arthritis.
NASA Astrophysics Data System (ADS)
Alqasemi, Umar; Li, Hai; Aguirre, Andres; Zhu, Quing
2011-03-01
Co-registering ultrasound (US) and photoacoustic (PA) imaging is a logical extension to conventional ultrasound because both modalities provide complementary information of tumor morphology, tumor vasculature and hypoxia for cancer detection and characterization. In addition, both modalities are capable of providing real-time images for clinical applications. In this paper, a Field Programmable Gate Array (FPGA) and Digital Signal Processor (DSP) module-based real-time US/PA imaging system is presented. The system provides real-time US/PA data acquisition and image display for up to 5 fps* using the currently implemented DSP board. It can be upgraded to 15 fps, which is the maximum pulse repetition rate of the used laser, by implementing an advanced DSP module. Additionally, the photoacoustic RF data for each frame is saved for further off-line processing. The system frontend consists of eight 16-channel modules made of commercial and customized circuits. Each 16-channel module consists of two commercial 8-channel receiving circuitry boards and one FPGA board from Analog Devices. Each receiving board contains an IC† that combines. 8-channel low-noise amplifiers, variable-gain amplifiers, anti-aliasing filters, and ADC's‡ in a single chip with sampling frequency of 40MHz. The FPGA board captures the LVDSξ Double Data Rate (DDR) digital output of the receiving board and performs data conditioning and subbeamforming. A customized 16-channel transmission circuitry is connected to the two receiving boards for US pulseecho (PE) mode data acquisition. A DSP module uses External Memory Interface (EMIF) to interface with the eight 16-channel modules through a customized adaptor board. The DSP transfers either sub-beamformed data (US pulse-echo mode or PAI imaging mode) or raw data from FPGA boards to its DDR-2 memory through the EMIF link, then it performs additional processing, after that, it transfer the data to the PC** for further image processing. The PC code
Kumagai, Kazutoshi; Koike, Hideyuki; Kudo, Yukina; Nagaoka, Ryo; Kubo, Kiyono; Kobayashi, Kazuto; Saijo, Yoshifumi
2011-01-01
High frequency ultrasound imaging has realized high resolution in vivo imaging of the biological tissues at a microscopic level. Human skin structure, especially sebaceous glands at the deep part of the dermis, was observed by three-dimensional ultrasound microscopy with the central frequency of 120 MHz. The visco-elasticity and surface sebum level of the observed region were measured by established testing devices. Both sebaceous glands density and surface sebum level were higher in cheek than those in forearm. The viscosity of forearm was lower than that of cheek. These results suggest that sebaceous glands may act as cushions of the skin besides their classical role of secreting sebum and some hormones. High frequency ultrasound imaging contributes to the evaluation of human skin aging.
Design and test of a PC-based portable three-dimensional ultrasound software system Ultra3D.
Xu, X George; Hum Na, Yong; Zhang, Tiantian
2008-02-01
Currently, portable ultrasound units lack three-dimensional (3D) image display, limiting their potential usefulness especially under remote and hostile operating environments where information must be intuitive and objective. A freehand 3D image processing and visualization software package, Ultra3D, has been developed and tested, especially to work with a miniaturized linear-array transducer probe that is connected to a laptop PC. This paper presents the software design and method to integrate Ultra3D into Terason's miniaturized SmartProbe for freehand 3D ultrasound imaging. Since images generated by Ultra3D are in a digital imaging and communications in medicine (DICOM) format, data sharing with others is easy.
Elasticity-based three dimensional ultrasound real-time volume rendering
NASA Astrophysics Data System (ADS)
Boctor, Emad M.; Matinfar, Mohammad; Ahmad, Omar; Rivaz, Hassan; Choti, Michael; Taylor, Russell H.
2009-02-01
Volumetric ultrasound imaging has not gained wide recognition, despite the availability of real-time 3D ultrasound scanners and the anticipated potential of 3D ultrasound imaging in diagnostic and interventional radiology. Their use, however, has been hindered by the lack of real-time visualization methods that are capable of producing high quality 3D rendering of the target/surface of interest. Volume rendering is a known visualization method, which can display clear surfaces out of the acquired volumetric data, and has an increasing number of applications utilizing CT and MRI data. The key element of any volume rendering pipeline is the ability to classify the target/surface of interest by setting an appropriate opacity function. Practical and successful real-time 3D ultrasound volume rendering can be achieved in Obstetrics and Angio applications where setting these opacity functions can be done rapidly, and reliably. Unfortunately, 3D ultrasound volume rendering of soft tissues is a challenging task due to the presence of significant amount of noise and speckle. Recently, several research groups have shown the feasibility of producing 3D elasticity volume from two consecutive 3D ultrasound scans. This report describes a novel volume rendering pipeline utilizing elasticity information. The basic idea is to compute B-mode voxel opacity from the rapidly calculated strain values, which can also be mixed with conventional gradient based opacity function. We have implemented the volume renderer using GPU unit, which gives an update rate of 40 volume/sec.
NASA Astrophysics Data System (ADS)
Mercado, Karla Patricia E.
Tissue engineering holds great promise for the repair or replacement of native tissues and organs. Further advancements in the fabrication of functional engineered tissues are partly dependent on developing new and improved technologies to monitor the properties of engineered tissues volumetrically, quantitatively, noninvasively, and nondestructively over time. Currently, engineered tissues are evaluated during fabrication using histology, biochemical assays, and direct mechanical tests. However, these techniques destroy tissue samples and, therefore, lack the capability for real-time, longitudinal monitoring. The research reported in this thesis developed nondestructive, noninvasive approaches to characterize the structural, biological, and mechanical properties of 3-D engineered tissues using high-frequency quantitative ultrasound and elastography technologies. A quantitative ultrasound technique, using a system-independent parameter known as the integrated backscatter coefficient (IBC), was employed to visualize and quantify structural properties of engineered tissues. Specifically, the IBC was demonstrated to estimate cell concentration and quantitatively detect differences in the microstructure of 3-D collagen hydrogels. Additionally, the feasibility of an ultrasound elastography technique called Single Tracking Location Acoustic Radiation Force Impulse (STL-ARFI) imaging was demonstrated for estimating the shear moduli of 3-D engineered tissues. High-frequency ultrasound techniques can be easily integrated into sterile environments necessary for tissue engineering. Furthermore, these high-frequency quantitative ultrasound techniques can enable noninvasive, volumetric characterization of the structural, biological, and mechanical properties of engineered tissues during fabrication and post-implantation.
NASA Astrophysics Data System (ADS)
Varjonen, Mari; Pamilo, Martti; Raulisto, Leena
2005-04-01
Our goal is to evaluate diagnostic digital breast tomosynthesis and ultrasound imaging clinical value in detecting and diagnosing early stage breast cancers. Determine if fusion imaging would decrease the number of biopsies and reduce further patient workup otherwise required to establish a definitive diagnosis. This paper presents the clinical results based on the study conducted at Helsinki University Central Hospital. Presentation demonstrates clinical dual modality images and results. Tomosynthesis of amorphous selenium based full field digital mammography system will be also presented. Forty asymptomatic women enrolled in the study based on prior identification of suspicious findings on screening mammograms where the possibility of breast cancer could not be excluded. Abnormal screening mammogram findings included tumor-like densities, parenchymal asymmetries and architectural distortions. Eight women were operated and 32 were not referred for surgery. Those cases, which were operated, three lesions represented ductal carcinoma in situ, two ductal carcinomas, one atypical ductal hyperplasia, one fibroadenoma and one radial scar. The 32 not operated cases revealed to be benign or superimposition of normal parenchymal breast tissue. The cases were returned to biennial screening. Ultrasound did not show clearly any lesions, but using tomosynthesis and ultrasound together we were able to analyze and locate the lesions exactly. Special tomosynthesis improves overall lesion detection and analysis. The value of tomosynthesis and ultrasound fusion imaging will be to provide additional clinical information in order to improve decision making accuracy to either confirm or exclude a suspected abnormality and in particular detect small breast cancers.
Quantification of Right and Left Ventricular Function With Real-Time Three-Dimensional Ultrasound
2007-11-02
But it is very delicate to increase the maximum number of iterations in every case since the septum wall that separates the two cavities very often...as the medial axis as developed by Pizer and Stetten [12]. V. CONCLUSION Quantification of RV and LV volumes with 2D ultrasound transducers is...the American Society of Echocardiography, vol. 14, pp. 275-284, 2001. [12] G. D. Stetten and S. M. Pizer, “ Medial -node models to identify and
NASA Technical Reports Server (NTRS)
Roth, Don J.; Whalen, Mike F.; Hendricks, J. Lynne; Bodis, James R.
2001-01-01
To interface with other solids, many surfaces are engineered via methods such as plating, coating, and machining to produce a functional surface ensuring successful end products. In addition, subsurface properties such as hardness, residual stress, deformation, chemical composition, and microstructure are often linked to surface characteristics. Surface topography, therefore, contains the signatures of the surface and possibly links to volumetric properties, and as a result serves as a vital link between surface design, manufacturing, and performance. Hence, surface topography can be used to diagnose, monitor, and control fabrication methods. At the NASA Glenn Research Center, the measurement of surface topography is important in developing high-temperature structural materials and for profiling the surface changes of materials during microgravity combustion experiments. A prior study demonstrated that focused air-coupled ultrasound at 1 MHz could profile surfaces with a 25-m depth resolution and a 400-m lateral resolution over a 1.4-mm depth range. In this work, we address the question of whether higher frequency focused water-coupled ultrasound can improve on these specifications. To this end, we employed 10- and 25-MHz focused ultrasonic transducers in the water-coupled mode. The surface profile results seen in this investigation for 25-MHz water-coupled ultrasound, in comparison to those for 1-MHz air-coupled ultrasound, represent an 8 times improvement in depth resolution (3 vs. 25 m seen in practice), an improvement of at least 2 times in lateral resolution (180 vs. 400 m calculated and observed in practice), and an improvement in vertical depth range of 4 times (calculated).
Freeling, Jessica L; Rezvani, Khosrow
2016-01-01
The relatively low success rates of current colorectal cancer (CRC) therapies have led investigators to search for more specific treatments. Vertebrate models of colorectal cancer are essential tools for the verification of new therapeutic avenues such as gene therapy. The evaluation of colorectal cancer in mouse models has been limited due to the lack of an accurate quantitative and longitudinal noninvasive method. This work introduces a method of three-dimensional micro-ultrasound reconstruction and microbubble administration for the comprehensive and longitudinal evaluation of CRC progression. This approach enabled quantification of both tumor volume and relative vascularity using a well-established inducible murine model of colon carcinogenesis. This inducible model recapitulated the adenocarcinoma sequence that occurs in human CRC allowing systematic in situ evaluation of the ultrasound technique. The administration of intravenous microbubbles facilitated enhancement of colon vascular contrast and quantification of relative vascularity of the mid and distal colon of the mouse in three dimensions. In addition, two-dimensional imaging in the sagittal orientation of the colon using Non-Linear Contrast Mode enabled calculation of relative blood volume and perfusion as the microbubbles entered the colon microvasculature. Quantitative results provided by the outlined protocol represent a noninvasive tool that can more accurately define CRC development and progression. This ultrasound technique will allow the practical and economical longitudinal study of murine CRC in both basic and preclinical studies. PMID:28053998
Moskalik, A; Carson, P L; Meyer, C R; Fowlkes, J B; Rubin, J M; Roubidoux, M A
1995-01-01
Use of multiple look directions, that is, compound imaging, has been shown previously to increase detection of specular reflectors and averaging of speckle noise in gray-scale images, often at the expense of spatial resolution and other misregistration errors. In color flow imaging, additional view angles can fill in vessels missed due to Doppler angle dropout and increase quantitative and visual Doppler accuracy by triangulation or a simple peak-frequency-shift combination algorithm. Image registration and unwarping throughout multiple three-dimensional (3D) volume sets should correct for many refraction artifacts, motion between and during compounded image sets and even, possibly, positioning errors between image sets, acquired months apart, to display growth of abnormalities. The registration described here does not provide sufficient accuracy for formation of enhanced coherent apertures, but shows promise in some cases to provide superior compound images and possibly comparisons of current and prior studies. In this study, the breast is stabilized by mild compression between a flat plate and a scanning membrane. Registration and unwarping is performed retrospectively on two separate volumetric data sets by defining pairs of corresponding points and, in some cases, line and plane segments. Three-dimensional linear affine transforms are performed using identified points, lines and planes. 3D nonlinear warped transforms are also possible given adequate numbers of identifiable points. More than two data sets are registered by selecting one as the standard, and registering the remainder to match. The most appropriate algorithm, such as averaging or maximum amplitude, may be used to combine the data sets for display. Significant success has been achieved in compound display of a test object and of the breast in vivo, even when there was relative motion or warping between image sets. In pulse-echo imaging, homologous feature registration for compounding appears to
Acharya, U Rajendra; Sree, S Vinitha; Swapna, G; Gupta, Savita; Molinari, Filippo; Garberoglio, R; Witkowska, Agnieszka; Suri, Jasjit S
2013-03-01
Ultrasonography has great potential in differentiating malignant thyroid nodules from the benign ones. However, visual interpretation is limited by interobserver variability, and further, the speckle distribution poses a challenge during the classification process. This article thus presents an automated system for tumor classification in three-dimensional contrast-enhanced ultrasonography data sets. The system first processes the contrast-enhanced ultrasonography images using complex wavelet transform-based filter to mitigate the effect of speckle noise. The higher order spectra features are then extracted and used as input for training and testing a fuzzy classifier. In the off-line training system, higher order spectra features are extracted from a set of images known as the training images. These higher order spectra features along with the clinically assigned ground truth are used to train the classifier and obtain an estimate of the classifier or training parameters. The ground truth tells the class label of the image (i.e. whether the image belongs to a benign or malignant nodule). During the online testing phase, the estimated classifier parameters are applied on the higher order spectra features that are extracted from the testing images to predict their class labels. The predicted class labels are compared with their corresponding original ground truth to evaluate the performance of the classifier. Without utilizing the complex wavelet transform filter, the fuzzy classifier demonstrated an accuracy of 91.6%, while utilizing the complex wavelet transform filter, the accuracy significantly boosted to 99.1%.
NASA Astrophysics Data System (ADS)
Wang, Qi; Xu, Diyun; Liu, Jianguo
2009-10-01
With the development of medical science, three-dimensional ultrasound and color power Doppler tomography shooting placenta is widely used. To determine whether the fetus's development is abnormal or not is mainly through the analysis of the capillary's distribution of the obtained images which are shot by the Doppler scanner. In this classification process, we will adopt Support Vector Machine classifier. SVM achieves substantial improvements over the statistical learning methods and behaves robustly over a variety of different learning tasks. Furthermore, it is fully automatic, eliminating the need for manual parameter tuning and can solve the small sample problem wonderfully well. So SVM classifier is valid and reliable in the identification of placentas and is more accurate with the lower error rate.
Visualization of Microvessels in Skin by Three-Dimensional Ultrasound Microscope
NASA Astrophysics Data System (ADS)
Saijo, Y.; Kobayashi, K.; Hozumi, N.; Tanaka, A.; Sakai, S.
A non-invasive imaging technique capable of visualizing microvessels through epidermis to subdermis has been strongly desired. A PVDF ultrasonic transducer with the central frequency of 100 MHz and the focal length of 3.2 mm was mechanically scanned over the objects by two linear servo motors controlled by a personal computer. A microvessel model was made of a tungsten wire with a diameter of 100-microns and placed in the water tank. The microvessel model was clearly visualized by 3D ultrasound microscope. In cases of skin imaging, conventional echo gel was used as the coupling medium between transducer and skin surface. In vivo 3D skin morphology was also clearly visualized. In dermis, a microvessel may be shown as small, round, lucent echo areas continuously observed in the serial sections. 3D structure of hair-follicle was also visualized from the skin surface to the bud of hair-follicle in dermis. The 3D ultrasound microscope noninvasively provides important information on the distribution of microvessels in skin.
Farris, Dominic James; Trewartha, Grant; McGuigan, M Polly; Lichtwark, Glen A
2013-02-15
The human Achilles tendon (AT) has often been considered to act as a single elastic structure in series with the muscles of the triceps surae. As such it has been commonly modelled as a Hookean spring of uniform stiffness. However, the free AT and the proximal AT have distinctly different structures that lend themselves to different elastic properties. This study aimed to use three-dimensional freehand ultrasound imaging to determine whether the proximal AT and the free AT exhibit different elastic behaviour during sub-maximal, fixed-end contractions of the triceps surae. Six male and five female participants (mean ± s.d. age=27 ± 5 years) performed fixed position contractions of the plantar-flexors on an isokinetic dynamometer at 50% of their maximum voluntary contraction in this position. Freehand three-dimensional ultrasound imaging was used to reconstruct the free-tendon and proximal AT at rest and during contraction. The free-tendon exhibited significantly (P=0.03) greater longitudinal strain (5.2 ± 1.7%) than the proximal AT (2.6 ± 2.0%). The lesser longitudinal strain of the proximal AT was linked to the fact that it exhibited considerable transverse (orthogonal to the longitudinal direction) strains (5.0 ± 4%). The transverse strain of the proximal AT is likely due to the triceps surae muscles bulging upon contraction, and thus the level of bulging may influence the elastic behaviour of the proximal AT. This might have implications for the understanding of triceps surae muscle-tendon interaction during locomotion, tendon injury mechanics and previous measurements of AT elastic properties.
Lin, Yen-Sheng; Koontz, Alicia M.; Boninger, Michael L.
2015-01-01
Background: A large percentage of individuals with spinal cord injury (SCI) report shoulder pain that can limit independence and quality of life. The pain is likely related to the demands placed on the shoulder by transfers and propulsion. Shoulder pathology has been linked to altered scapular mechanics; however, current methods to evaluate scapular movement are invasive, require ionizing radiation, are subject to skin-based motion artifacts, or require static postures. Objective: To investigate the feasibility of applying 3-dimensional ultrasound methods, previously used to look at scapular position in static postures, to evaluate dynamic scapular movement. Method: This study evaluated the feasibility of the novel application of a method combining 2-dimensional ultrasound and a motion capture system to determine 3-dimensional scapular position during dynamic arm elevation in the scapular plane with and without loading. Results: Incremental increases in scapular rotations were noted for extracted angles of 30°, 45°, 60°, and 75° of humeral elevation. Group differences were evaluated between a group of 16 manual wheelchair users (MWUs) and a group of age- and gender-matched able-bodied controls. MWUs had greater scapular external rotation and baseline pathology on clinical exam. MWUs also had greater anterior tilting, with this difference further accentuated during loading. The relationship between demographics and scapular positioning was also investigated, revealing that increased age, pathology on clinical exam, years since injury, and body mass index were correlated with scapular rotations associated with impingement (internal rotation, downward rotation, and anterior tilting). Conclusion: Individuals with SCI, as well as other populations who are susceptible to shoulder pathology, may benefit from the application of this imaging modality to quantitatively evaluate scapular positioning and effectively target therapeutic interventions. PMID:26689695
Sebag, Igal A; Morgan, John G; Handschumacher, Mark D; Marshall, Jane E; Nesta, Francesca; Hung, Judy; Picard, Michael H; Levine, Robert A
2005-10-15
Two-dimensional (2-D) planimetry is limited by the technical demands, time, and observer variability required to locate the minimal orifice area, limiting the confident clinical reporting of mitral valve area (MVA). In 27 consecutive patients, MVA was determined independently by 2 observers using the conventional 2-D method and a new 3-D-guided method. Using a matrix-array probe, the valve was visualized in a long-axis view and a cursor steered to intersect the leaflet tips and provide a perpendicular short-axis plane viewed side-by-side. Two-dimensional and 3-D-guided methods allowed planimetry in 24 patients. Consistent with better orifice localization, 3-D guidance eliminated the overestimation of internal orifice diameters in the planimetered short-axis view relative to the limiting diameter defined by the long-axis view (for 3-D guidance, 0.73 +/- 0.20 vs 0.73 +/- 0.21 cm, p = 0.98, vs 0.90 +/- 0.27 cm in the 2-D short-axis view, p <0.01). Accordingly, mean values for the smallest orifice area by 3-D guidance were less than by 2-D imaging (1.4 +/- 0.5 vs 1.5 +/- 0.5 cm(2), p <0.01), changing the clinical severity classification in 11 of 24 patients (46%). The 2-D method also overestimated MVA relative to 3-D guidance compared with Doppler pressure halftime and (n = 6) Gorlin areas. Phantom studies verified no differences in resolution for the 2 acquisition modes. Three-dimensional guidance reduced intraobserver variability from 9.8% to 3.8% (SEE 0.14 to 0.06 cm(2), p <0.01) and interobserver variability from 10.6% to 6.1% (SEE 0.15 to 0.09 cm(2), p <0.02). In conclusion, matrix-array technology provides a feasible and highly reproducible direct 3-D-guided method for measuring the limiting mitral orifice area.
Wirtzfeld, L A; Graham, K C; Groom, A C; Macdonald, I C; Chambers, A F; Fenster, A; Lacefield, J C
2006-05-21
The identification and quantification of tumour volume measurement variability is imperative for proper study design of longitudinal non-invasive imaging of pre-clinical mouse models of cancer. Measurement variability will dictate the minimum detectable volume change, which in turn influences the scheduling of imaging sessions and the interpretation of observed changes in tumour volume. In this paper, variability is quantified for tumour volume measurements from 3D high-frequency ultrasound images of murine liver metastases. Experimental B16F1 liver metastases were analysed in different size ranges including less than 1 mm3, 1-4 mm3, 4-8 mm3 and 8-70 mm3. The intra- and inter-observer repeatability was high over a large range of tumour volumes, but the coefficients of variation (COV) varied over the volume ranges. The minimum and maximum intra-observer COV were 4% and 14% for the 1-4 mm3 and <1 mm3 tumours, respectively. For tumour volumes measured by segmenting parallel planes, the maximum inter-slice distance that maintained acceptable measurement variability increased from 100 to 600 microm as tumour volume increased. Comparison of free breathing versus ventilated animals demonstrated that respiratory motion did not significantly change the measured volume. These results enable design of more efficient imaging studies by using the measured variability to estimate the time required to observe a significant change in tumour volume.
Three-Dimensional Strains in Human Posterior Sclera Using Ultrasound Speckle Tracking
Pavlatos, Elias; Perez, Benjamin Cruz; Morris, Hugh J.; Chen, Hong; Palko, Joel R.; Pan, Xueliang; Weber, Paul A.; Hart, Richard T.; Liu, Jun
2016-01-01
Intraocular pressure (IOP) induced strains in the peripapillary sclera may play a role in glaucoma progression. Using inflation testing and ultrasound speckle tracking, the 3D strains in the peripapillary sclera were measured in nine human donor globes. Our results showed that the peripapillary sclera experienced through-thickness compression and meridional stretch during inflation, while minimal circumferential dilation was observed when IOP was increased from 10 to 19 mmHg. The maximum shear was primarily oriented in the through-thickness, meridional cross sections and had a magnitude slightly larger than the first principal strain. The tissue volume had minimal overall change, confirming near-incompressibility of the sclera. Substantial strain heterogeneity was present in the peripapillary region, with local high strain areas likely corresponding to structural heterogeneity caused by traversing blood vessels. These 3D strain characteristics provide new insights into the biomechanical responses of the peripapillary sclera during physiological increases of IOP. Future studies are needed to confirm these findings and investigate the role of these biomechanical characteristics in ocular diseases. PMID:26632258
O'Reilly, Meaghan A.; Jones, Ryan M.; Hynynen, Kullervo
2014-01-01
There is an increasing interest in bubble-mediated focused ultrasound (FUS) interventions in the brain. However, current technology lacks the ability to spatially monitor the interaction of the microbubbles with the applied acoustic field, something which is critical for safe clinical translation of these treatments. Passive acoustic mapping could offer a means for spatially monitoring microbubble emissions that relate to bubble activity and associated bioeffects. In this study a hemispherical receiver array was integrated within an existing transcranial therapy array to create a device capable of both delivering therapy and monitoring the process via passive imaging of bubble clouds. A 128-element receiver array was constructed and characterized for varying bubble concentrations and source spacings. Initial in vivo feasibility testing was performed. The system was found to be capable of monitoring bubble emissions down to single bubble events through an ex vivo human skull. The lateral resolution of the system was found to be between 1.25-2 mm and the axial resolution between 2-3.5 mm, comparable to the resolution of MRI-based temperature monitoring during thermal FUS treatments in the brain. The results of initial in vivo experiments show that bubble activity can be mapped starting at pressure levels below the threshold for Blood-Brain barrier disruption. This study presents a feasible solution for imaging bubble activity during cavitation-mediated FUS treatments in the brain. PMID:24658252
San José-Estépar, Raúl; Martín-Fernández, Marcos; Caballero-Martínez, P Pablo; Alberola-López, Carlos; Ruiz-Alzola, Juan
2003-02-01
Several techniques have been described in the literature in recent years for the reconstruction of a regular volume out of a series of ultrasound (US) slices with arbitrary orientations, typically scanned by means of US freehand systems. However, a systematic approach to such a problem is still missing. This paper focuses on proposing a theoretical framework for the 3-D US volume reconstruction problem. We introduce a statistical method for the construction and trimming of the sampling grid where the reconstruction will be carried out. The results using in vivo US data demonstrate that the computed reconstruction grid that encloses the region-of-interest (ROI) is smaller than those obtained from other reconstruction methods in those cases where the scanning trajectory deviates from a pure straight line. In addition, an adaptive Gaussian interpolation technique is studied and compared with well-known interpolation methods that have been applied to the reconstruction problem in the past. We find that the proposed method numerically outperforms former proposals in several control studies; subjective visual results also support this conclusion and highlight some potential deficiencies of methods previously proposed.
ERIC Educational Resources Information Center
Bressmann, Tim; Thind, Parveen; Uy, Catherine; Bollig, Carmen; Gilbert, Ralph W.; Irish, Jonathan C.
2005-01-01
The functional determinants for a good speech outcome after a partial tongue resection and reconstruction are not well established. The purpose of the present study was to assess the protrusion, grooving and symmetry of the tongue during sustained speech sound production using three-dimensional ultrasound. The participants were twelve normal…
Noriega, Sandra; Hasanova, Gulnara; Subramanian, Anuradha
2013-01-01
The impact of low-intensity diffuse ultrasound (LIDUS) stimulation on the cytoskeletal organization of chondrocytes seeded in three-dimensional (3D) scaffolds was evaluated. Chondrocytes seeded on 3D chitosan matrices were exposed to LIDUS at 5.0 MHz (approx. 15 kPa, 51 s, 4 applications/day) in order to study the organization of actin, tubulin and vimentin. The results showed that actin presented a punctate cytosolic distribution and tubulin presented a quasiparallel organization of microtubules, whereas vimentin distribution was unaffected. Chondrocytes seeded on 3D scaffolds responded to US stimulation by the disruption of actin stress fibers and were sensitive to the presence of Rho-activated kinase (ROCK) inhibitor (Y27632). The gene expression of ROCK-I, a key element in the formation of stress fibers and mDia1, was significantly upregulated under the application of US. We conclude that the results of both the cytoskeletal analyses and gene expression support the argument that the presence of punctate actin upon US stimulation was accompanied by the upregulation of the RhoA/ROCK pathway.
Liu, Haixia; Tan, Tao; van Zelst, Jan; Mann, Ritse; Karssemeijer, Nico; Platel, Bram
2014-07-01
We investigated the benefits of incorporating texture features into an existing computer-aided diagnosis (CAD) system for classifying benign and malignant lesions in automated three-dimensional breast ultrasound images. The existing system takes into account 11 different features, describing different lesion properties; however, it does not include texture features. In this work, we expand the system by including texture features based on local binary patterns, gray level co-occurrence matrices, and Gabor filters computed from each lesion to be diagnosed. To deal with the resulting large number of features, we proposed a combination of feature-oriented classifiers combining each group of texture features into a single likelihood, resulting in three additional features used for the final classification. The classification was performed using support vector machine classifiers, and the evaluation was done with 10-fold cross validation on a dataset containing 424 lesions (239 benign and 185 malignant lesions). We compared the classification performance of the CAD system with and without texture features. The area under the receiver operating characteristic curve increased from 0.90 to 0.91 after adding texture features ([Formula: see text]).
Daoud, Mohammad I; Lacefield, James C
2009-09-07
Computational modeling is an important tool in ultrasound imaging research, but realistic three-dimensional (3D) simulations can exceed the capabilities of serial computers. This paper uses a 3D simulator based on a k-space method that incorporates relaxation absorption and nonreflecting boundary conditions. The simulator, which runs on computer clusters, computes the propagation of a single wavefront. In this paper, an allocation algorithm is introduced to assign each scan line to a group of nodes and use multiple groups to compute independent lines concurrently. The computational complexity required for realistic simulations is analyzed using example calculations of ultrasonic propagation and attenuation in the 30-50 MHz band. Parallel efficiency for B-mode imaging simulations is evaluated for various numbers of scan lines and cluster nodes. An aperture-projection technique is introduced to simulate imaging with a focused transducer using reduced computation grids. This technique is employed to synthesize B-mode images that show realistic 3D refraction artifacts. Parallel computing using 20 nodes to compute groups of ten scan lines concurrently reduced the execution time for each image to 18.6 h, compared to a serial execution time of 357.5 h. The results demonstrate that fully 3D imaging simulations are practical using contemporary computing technology.
Liu, Haixia; Tan, Tao; van Zelst, Jan; Mann, Ritse; Karssemeijer, Nico; Platel, Bram
2014-01-01
Abstract. We investigated the benefits of incorporating texture features into an existing computer-aided diagnosis (CAD) system for classifying benign and malignant lesions in automated three-dimensional breast ultrasound images. The existing system takes into account 11 different features, describing different lesion properties; however, it does not include texture features. In this work, we expand the system by including texture features based on local binary patterns, gray level co-occurrence matrices, and Gabor filters computed from each lesion to be diagnosed. To deal with the resulting large number of features, we proposed a combination of feature-oriented classifiers combining each group of texture features into a single likelihood, resulting in three additional features used for the final classification. The classification was performed using support vector machine classifiers, and the evaluation was done with 10-fold cross validation on a dataset containing 424 lesions (239 benign and 185 malignant lesions). We compared the classification performance of the CAD system with and without texture features. The area under the receiver operating characteristic curve increased from 0.90 to 0.91 after adding texture features (p<0.001). PMID:26158036
Saravelos, Sotirios H; Li, Tin-Chiu
2016-05-01
The recent ESHRE-ESGE classification for female genital anomalies attempts to promote objectivity in diagnosis of normal and septate uteri. The aim of this study was to ascertain whether the uterine cavity indentation - the characteristic feature of septate uteri - varies significantly throughout the cycle. Seventy consecutive women underwent three-dimensional ultrasound twice: 35 during the proliferative and luteal phase of a natural cycle, and 35 during the first and final day of a stimulated cycle. Endometrial thickness, interostial distance, cavity indentation and percentage of cavity indentation were all assessed in accordance with the ESHRE-ESGE consensus on diagnosis of female genital anomalies. Overall, throughout both cycles, there was a significant increase in endometrial thickness (from 4.6 mm to 10.2 mm; P < 0.001) and interostial distance (from 30.1 mm to 35.1 mm; P < 0.001), which was associated with a significant reduction in the percentage of cavity indentation (from 30.3% to 15.0%; P < 0.001). Between the first and second assessment, 3/70 (4.3%) patients had a change in diagnosis from septate to normal uterus, although this did not reach statistical significance. This observation of a significant intra-cycle variation of the uterine cavity indentation has important implications for both clinical practice and research.
Kot, Brian C W; Ying, Michael T C; Brook, Fiona M; Kinoshita, Reimi E
2012-03-01
The assessment of thyroid volume plays an indispensable role in the diagnosis and management of different thyroid diseases. The present study evaluates the accuracy of dolphin thyroid volume measurement as determined by four two-dimensional (2D) ultrasound methods (A-D), with a standard of reference using three-dimensional (3D) ultrasound. The measurement accuracy for different recognized thyroid configuration is also evaluated. Inter- and intraoperator variability of the measurement methods was determined. Thyroid ultrasound examinations were conducted in 16 apparently healthy Indo-Pacific bottlenose dolphins (Tursiops aduncus) with 2D and 3D ultrasound under identical scanning conditions. All 2D ultrasound measurement methods yielded high accuracies (79.9-81.3%) when compared with the 3D ultrasound measurement, and had high measurement reproducibility (77.6-86.2%) and repeatability (78.1-99.7%). For 2D ultrasound measurements, Methods A and B were more accurate and reliable than Methods C and D, regardless of thyroid configuration. Ultrasound is useful in the measurement of thyroid volume in bottlenose dolphins. For the first time, a reliable ultrasound scanning protocol for measuring dolphin thyroid volume was developed, which provides a means to establish a normative reference for the diagnosis of thyroid pathologies and to monitor the thyroid volume during the course of treatment in living dolphins. Key words: 3D ultrasound, Indo-Pacific bottlenose dolphin, thyroid volume measurement, Tursiops aduncus.
Addley, Susan; Ali, Amanda
2017-01-01
Background Pre-eclampsia and placental causes of intrauterine growth restriction (IUGR) are part of the same spectrum of disorders. In IUGR, there is preferential shunting of blood to the fetal brain at the expense of other organs. We wanted to demonstrate that this also occurs in pre-eclampsia using three dimensional (3D) ultrasound. The 3D indices of perfusion are: flow index (FI), vascular index (VI) and vascularisation flow index (VFI) which reflect tissue vascularity and flow intensity. Methods Fourteen normal pregnant women and 14 with diagnosed pre-eclampsia were recruited. Scanning was conducted by 2 observers using a Voluson E8 machine. Perfusion was measured at a pre-defined position within the fetal brain and fetal liver. The power Doppler signals were quantified using the ‘histogram facility’ to generate 3 indices of vascularity: FI, VI and VFI. The unpaired t-test was used to compare differences between groups. The hypothesis was that fetal brain FI, VI and VFI would be similar between women with normal pregnancy and women with pre-eclampsia, but measurements would be reduced in the fetal liver in women with pre-eclampsia. Results Maternal characteristics of age, body mass index and gestation were not different between groups. The depth of insonnation did not differ between groups. Fetal cerebral perfusion was not different between women with a normal pregnancy compared to women with pre-eclampsia. The mean (SD) for FI was 22.4 (5.7) vs. 21.1 (4.3) respectively (p=0.49). For VI, the mean (SD) was as 64.7 (40.4) vs. 79.1 (27.4) respectively (p=0.28). For VFI, the mean (SD) was 14.8 (10.3) vs. 16.1 (5.5) respectively (p = 0.66). Fetal hepatic perfusion was not different between women with a normal pregnancy compared to women with pre-eclampsia. The mean (SD) for FI was 34.4 (19.9) vs. 27.8 (11.0) respectively (p = 0.28). For VI, mean (SD) was 67.6 (36.0) vs. 87.3 (25.8) respectively (p=0.11). For VFI, the mean (SD) was 19.6 (11.6) vs. 23.1 (10
Hosseinkhah, N.; Hynynen, K.
2012-01-01
Ultrasound contrast agents inside a microvessel, when driven by ultrasound, oscillate and induce mechanical stresses on the vessel wall. These mechanical stresses can produce beneficial therapeutic effects but also induce vessel rupture if the stresses are too high. Therefore, it is important to use sufficiently low pressure amplitudes to avoid rupturing the vessels while still inducing the desired therapeutic effects. In this work, we developed a comprehensive three dimensional model of a confined microbubble inside a vessel while considering the bubble shell properties, blood viscosity, vessel wall curvature and the mechanical properties of the vessel wall. Two bubble models with the assumption of a spherical symmetric bubble and a simple asymmetrical bubble were simulated. This work was validated with previous experimental results and enabled us to evaluate the microbubbles’ behaviour and the resulting mechanical stresses induced on the vessel walls. In this study the fluid shear and circumferential stresses were evaluated as indicators of the mechanical stresses. The effects of acoustical parameters, vessel viscoelasticity and rigidity, vessel/bubble size and off-center bubbles on bubble behaviour and stresses on the vessel were investigated. The fluid shear and circumferential stresses acting on the vessel varied with time and location. As the frequency changed, the microbubble oscillated with the highest amplitude at its resonance frequency which was different from the resonance frequency of an unbound bubble. The bubble resonance frequency increased as the rigidity of a flexible vessel increased. The fluid shear and circumferential stresses peaked at frequencies above the bubble’s resonance frequency. The more rigid the vessels were, the more damped the bubble oscillations. The synergistic effect of acoustic frequency and vessel elasticity had also been investigated, since the circumferential stress showed either an increasing trend or a decreasing one
NASA Astrophysics Data System (ADS)
Duan, Qi; Angelini, Elsa D.; Laine, Andrew
2004-04-01
Three-dimensional ultrasound machines based on matrix phased-array transducers are gaining predominance for real-time dynamic screening in cardiac and obstetric practice. These transducers array acquire three-dimensional data in spherical coordinates along lines tiled in azimuth and elevation angles at incremental depth. This study aims at evaluating fast filtering and scan conversion algorithms applied in the spherical domain prior to visualization into Cartesian coordinates for visual quality and spatial measurement accuracy. Fast 3d scan conversion algorithms were implemented and with different order interpolation kernels. Downsizing and smoothing of sampling artifacts were integrated in the scan conversion process. In addition, a denoising scheme for spherical coordinate data with 3d anisotropic diffusion was implemented and applied prior to scan conversion to improve image quality. Reconstruction results under different parameter settings, such as different interpolation kernels, scaling factor, smoothing options, and denoising, are reported. Image quality was evaluated on several data sets via visual inspections and measurements of cylinder objects dimensions. Error measurements of the cylinder's radius, reported in this paper, show that the proposed fast scan conversion algorithm can correctly reconstruct three-dimensional ultrasound in Cartesian coordinates under tuned parameter settings. Denoising via three-dimensional anisotropic diffusion was able to greatly improve the quality of resampled data without affecting the accuracy of spatial information after the modification of the introduction of a variable gradient threshold parameter.
Acebes, Carlos; McKay, Neil; Ciechomska, Anna; Alcorn, Nicola; Harvie, John P; Robson, Barbara; Groenendijk, Nico; McDonald, Moira; Wilson, Alison; Garrido, Jesus
2017-02-01
The aim of the study was to assess agreement between three-dimensional volumetric ultrasound (3D US) performed by inexperienced staff and real-time conventional ultrasound (2D US) performed by experienced rheumatologists in detecting and scoring rheumatoid arthritis (RA) lesions. Thirty-one RA patients underwent examination of seven joints by 2D and 3D US for synovitis and tenosynovitis in B and PD modes and erosions in B mode. A global score for synovitis and global counts for synovitis, tenosynovitis and erosions were also calculated for every patient. Agreement between 2D and 3D US was analysed for counts and scores at the patient level with the intraclass correlation coefficient (ICC) and for counts at the joint level with Cohen's kappa coefficient. B-mode synovitis was detected at a median of five joints in each patient, frequently in wrists and hand joints but less frequently in foot joints. PD-mode synovitis, tenosynovitis and erosions were detected less frequently. All ICCs for agreement between 2D and 3D US findings were significant. All kappa coefficients were significant for B- and PD-mode synovitis and for erosions (except PIP3), while those for tenosynovitis were only significant for MCP2 (B and PD modes) and PIP2 (B mode). Although the 3D US volumes were acquired by inexperienced operators, agreement between 2D and 3D US was acceptable in detecting and scoring synovitis. A higher level of agreement was attained for patient-level global scores and counts than for individual joints.
Ding, Ting; Hu, Hong; Bai, Chen; Guo, Shifang; Yang, Miao; Wang, Supin; Wan, Mingxi
2016-07-01
Cavitation plays important roles in almost all high-intensity focused ultrasound (HIFU) applications. However, current two-dimensional (2D) cavitation mapping could only provide cavitation activity in one plane. This study proposed a three-dimensional (3D) ultrasound plane-by-plane active cavitation mapping (3D-UPACM) for HIFU in free field and pulsatile flow. The acquisition of channel-domain raw radio-frequency (RF) data in 3D space was performed by sequential plane-by-plane 2D ultrafast active cavitation mapping. Between two adjacent unit locations, there was a waiting time to make cavitation nuclei distribution of the liquid back to the original state. The 3D cavitation map equivalent to the one detected at one time and over the entire volume could be reconstructed by Marching Cube algorithm. Minimum variance (MV) adaptive beamforming was combined with coherence factor (CF) weighting (MVCF) or compressive sensing (CS) method (MVCS) to process the raw RF data for improved beamforming or more rapid data processing. The feasibility of 3D-UPACM was demonstrated in tap-water and a phantom vessel with pulsatile flow. The time interval between temporal evolutions of cavitation bubble cloud could be several microseconds. MVCF beamformer had a signal-to-noise ratio (SNR) at 14.17dB higher, lateral and axial resolution at 2.88times and 1.88times, respectively, which were compared with those of B-mode active cavitation mapping. MVCS beamformer had only 14.94% time penalty of that of MVCF beamformer. This 3D-UPACM technique employs the linear array of a current ultrasound diagnosis system rather than a 2D array transducer to decrease the cost of the instrument. Moreover, although the application is limited by the requirement for a gassy fluid medium or a constant supply of new cavitation nuclei that allows replenishment of nuclei between HIFU exposures, this technique may exhibit a useful tool in 3D cavitation mapping for HIFU with high speed, precision and resolution
Shih, J C; Hsu, W C; Chou, H C; Peng, S S; Chen, L K; Chang, Y L; Hsieh, F J
2005-01-01
Recent attempts at predelivery management of obstructed fetal airways have focused on the EXIT (ex-utero intrapartum treatment) procedure, which allows sufficient time to secure the fetal airway through preservation of uteroplacental gas exchange. We report a fetus with an exophytic oral tumor noted at 34 weeks of gestation. In this case, three-dimensional (3D) ultrasound allowed a complete and interactive evaluation of the tumor and related facial anatomy, and confirmed that access to the fetal airway was unlikely during delivery. Fetal magnetic resonance imaging (MRI) further demonstrated that the tumor originated in the nasopharynx and obstructed the upper airway. Both imaging results led to a final decision to offer an EXIT procedure for the neonate. At 36 weeks' gestation, a successful EXIT procedure was performed to reduce the risk of respiratory distress immediately after birth. This report highlights the value of 3D ultrasound and MRI as essential prerequisites for optimization of the triage process in selecting EXIT candidates.
House, Michael; Feltovich, Helen; Hall, Timothy J; Stack, Trevor; Patel, Atur; Socrate, Simona
2015-01-01
Cervical shortening and cervical insufficiency contribute to a significant number of preterm births. However, the deformation mechanisms that control how the cervix changes its shape from long and closed to short and dilated are not clear. Investigation of the biomechanical problem is limited by 1) lack of thorough characterization of the three-dimensional anatomical changes associated with cervical deformation and 2) difficulty measuring cervical tissue properties in vivo. The objective of the present study was to explore the feasibility of using three-dimensional ultrasound and fundal pressure to obtain anatomically accurate numerical models of large-strain cervical deformation during pregnancy and enable non-invasive assessment of cervical tissue compliance. Healthy subjects (n=6) and one subject with acute cervical insufficiency in the midtrimester were studied. Extended field of view ultrasound images were obtained of the entire uterus and cervix. These images aided construction of anatomically accurate numerical models. Cervical loading was achieved with fundal pressure, which was quantified with a vaginal pressure catheter. In one subject, the anatomical response to fundal pressure was matched by a model-based simulation of the deformation response, thereby deriving the corresponding cervical mechanical properties and showing the feasibility of non-invasive assessment of compliance. The results of this pilot study demonstrate the feasibility of a biomechanical modeling framework for estimating cervical mechanical properties in vivo. An improved understanding of cervical biomechanical function will clarify the pathophysiology of cervical shortening. PMID:22655487
NASA Astrophysics Data System (ADS)
Anis, Fatima; Su, Richard; Nadvoretsky, Vyacheslav V.; Conjusteau, André; Ermilov, Sergey A.; Oraevsky, Alexander A.; Anastasio, Mark A.
2013-03-01
We developed the first prototype of dual-modality imager combining optoacoustic tomography (OAT) and laser ultrasound tomography (UST) using computer models followed by experimental validation. The system designed for preclinical biomedical research can concurrently yield images depicting both the absorbed optical energy density and acoustic properties (speed of sound) of an object. In our design of the UST imager, we seek to replace conventional electrical generation of ultrasound waves by laser-induced ultrasound (LU). While earlier studies yielded encouraging results [Manohar, et al., Appl. Phys. Lett, 131911, 2007], they were limited to two-dimensional (2D) geometries. In this work, we conduct computer-simulation studies to investigate different designs for the 3D LU UST imager. The number and location of the laser ultrasound emitters, which are constrained to reside on the cylindrical surface opposite to the arc of detectors, are optimized. In addition to the system parameters, an iterative image reconstruction algorithm was optimized. We demonstrate that high quality volumetric maps of the speed of sound can be reconstructed when only 32 emitters and 128 receiving transducers are employed to record time-of-flight data at 360 tomographic view angles. The implications of the proposed system for small animal and breast-cancer imaging are discussed.
NASA Astrophysics Data System (ADS)
Patch, S. K.; Kireeff Covo, M.; Jackson, A.; Qadadha, Y. M.; Campbell, K. S.; Albright, R. A.; Bloemhard, P.; Donoghue, A. P.; Siero, C. R.; Gimpel, T. L.; Small, S. M.; Ninemire, B. F.; Johnson, M. B.; Phair, L.
2016-08-01
The potential of particle therapy due to focused dose deposition in the Bragg peak has not yet been fully realized due to inaccuracies in range verification. The purpose of this work was to correlate the Bragg peak location with target structure, by overlaying the location of the Bragg peak onto a standard ultrasound image. Pulsed delivery of 50 MeV protons was accomplished by a fast chopper installed between the ion source and the cyclotron inflector. The chopper limited the train of bunches so that 2 Gy were delivered in 2 μ \\text{s} . The ion pulse generated thermoacoustic pulses that were detected by a cardiac ultrasound array, which also produced a grayscale ultrasound image. A filtered backprojection algorithm focused the received signal to the Bragg peak location with perfect co-registration to the ultrasound images. Data was collected in a room temperature water bath and gelatin phantom with a cavity designed to mimic the intestine, in which gas pockets can displace the Bragg peak. Phantom experiments performed with the cavity both empty and filled with olive oil confirmed that displacement of the Bragg peak due to anatomical change could be detected. Thermoacoustic range measurements in the waterbath agreed with Monte Carlo simulation within 1.2 mm. In the phantom, thermoacoustic range estimates and first-order range estimates from CT images agreed to within 1.5 mm.
Yang, Renhuan; Li, Xu; Song, Aiguo; He, Bin; Yan, Ruqiang
2012-11-21
Electrical properties of biological tissues are highly sensitive to their physiological and pathological status. Thus it is of importance to image electrical properties of biological tissues. However, spatial resolution of conventional electrical impedance tomography (EIT) is generally poor. Recently, hybrid imaging modalities combining electric conductivity contrast and ultrasonic resolution based on the acousto-electric effect has attracted considerable attention. In this study, we propose a novel three-dimensional (3D) noninvasive ultrasound Joule heat tomography (UJHT) approach based on the acousto-electric effect using unipolar ultrasound pulses. As the Joule heat density distribution is highly dependent on the conductivity distribution, an accurate and high-resolution mapping of the Joule heat density distribution is expected to give important information that is closely related to the conductivity contrast. The advantages of the proposed ultrasound Joule heat tomography using unipolar pulses include its simple inverse solution, better performance than UJHT using common bipolar pulses and its independence of a priori knowledge of the conductivity distribution of the imaging object. Computer simulation results show that using the proposed method, it is feasible to perform a high spatial resolution Joule heat imaging in an inhomogeneous conductive media. Application of this technique on tumor scanning is also investigated by a series of computer simulations.
Dangas, George D.; Maehara, Akiko; Evrard, Solene M.; Sartori, Samantha; Li, Jennifer R.; Chirumamilla, Amala P.; Nomura-Kitabayashi, Aya; Gukathasan, Nilusha; Hassanin, Ahmed; Baber, Usman; Fahy, Martin; Fuster, Valentin; Mintz, Gary S.; Kovacic, Jason C.
2014-01-01
Aims Emerging data have indicated unexpected complexity in the regulation of vascular and bone calcification. In particular, several recent studies have challenged the concept of a universally positive relationship between body morphology [weight, height, body mass index (BMI), body surface area (BSA)] and the extent of vascular calcification. We sought to clarify these discrepancies and investigated the relationship between index lesion coronary artery calcification (CAC) and body morphology in patients undergoing percutaneous coronary intervention (PCI) using three-dimensional intravascular ultrasound (IVUS). Methods and results We analysed CAC in patients who underwent PCI with pre-intervention IVUS imaging. The main outcome measure was the calcium index (CalcIndex); a three-dimensional IVUS-derived measure of total calcification per obstructive coronary lesion. A total of 346 patients (65.3 ± 10.6 years; 29.5% females) underwent PCI with IVUS-based CAC assessment. CalcIndex was categorized as zero–low (0–0.1399; n = 152) or intermediate–high (0.1400–1.2541; n = 194). All measures of body morphology were lower in patients with intermediate–high CalcIndex (height, P = 0.024; weight, P = 0.008; BMI, P = 0.064; BSA, P = 0.005). In adjusted multivariable models, weight and BSA were independent inverse predictors of intermediate–high CalcIndex [weight: odds ratio (OR) 0.986, P = 0.017; BSA: OR 0.323, P = 0.012] while CalcIndex also trended towards an inverse association with both height (P = 0.068) and BMI (P = 0.064). These independent inverse associations were consistent across multiple clinical subgroups, including stratification by age, race, gender, diabetes, and renal impairment. Conclusion Using three-dimensional IVUS to assess vascular calcification, these data confirm an independent, inverse relationship between body size and index lesion CAC in patients with obstructive coronary artery disease. PMID:23904334
NASA Astrophysics Data System (ADS)
Zafar, Haroon; Gaynard, Sean; O'Flatharta, Cathal; Doroshenkova, Tatiana; Devine, Declan; Sharif, Faisal; Barry, Frank; Hayes, Jessica; Murphy, Mary; Leahy, Martin J.
2016-03-01
Stem cell based treatments hold great potential and promise to address many unmet clinical needs. The importance of non-invasive imaging techniques to monitor transplanted stem cells qualitatively and quantitatively is crucial. The objective of this study was to create a critical size bone defect in the rat femur and then assess the ability of the differentiated mesenchymal stem cells (MSCs) to repair the defect using high frequency co-registered photoacoustic(PA)/ultrasound(US) imaging and micro computed tomography (μCT) over an 8 week period. Combined PA and US imaging was performed using 256 elements, 21 MHz frequency linear-array transducer combined with multichannel collecting system. In vivo 3D PA and US images of the defect bone in the rat femur were acquired after 4 and 8 weeks of the surgery. 3D co-registered structural such as microvasculature and the functional images such as total concentration of haemoglobin (HbT) and the haemoglobin oxygen saturation (sO2) were obtained using PA and US imaging. Bone formation was assessed after 4 and 8 weeks of the surgery by μCT. High frequency linear-array based coregistered PA/US imaging has been found promising in terms of non-invasiveness, sensitivity, adaptability, high spatial and temporal resolution at sufficient depths for the assessment of the reparative ability of MSCs in a rat critical size bone repair defect model.
Bharat, Shyam; Fisher, Ted G; Varghese, Tomy; Hall, Timothy J; Jiang, Jingfeng; Madsen, Ernest L; Zagzebski, James A; Lee, Fred T
2008-08-01
Because ablation therapy alters the elastic modulus of tissues, emerging strain imaging methods may enable clinicians for the first time to have readily available, cost-effective, real-time guidance to identify the location and boundaries of thermal lesions. Electrode displacement elastography is a method of strain imaging tailored specifically to ultrasound-guided electrode-based ablative therapies (e.g., radio-frequency ablation). Here tissue deformation is achieved by applying minute perturbations to the unconstrained end of the treatment electrode, resulting in localized motion around the end of the electrode embedded in tissue. In this article, we present a method for three-dimensional (3D) elastographic reconstruction from volumetric data acquired using the C7F2 fourSight four-dimensional ultrasound transducer, provided by Siemens Medical Solutions USA, Inc. (Issaquah, WA, USA). Lesion reconstruction is demonstrated for a spherical inclusion centered in a tissue-mimicking phantom, which simulates a thermal lesion embedded in a normal tissue background. Elastographic reconstruction is also performed for a thermal lesion created in vitro in canine liver using radio-frequency ablation. Postprocessing is done on the acquired raw radio-frequency data to form surface-rendered 3D elastograms of the inclusion. Elastographic volume estimates of the inclusion compare reasonably well with the actual known inclusion volume, with 3D electrode displacement elastography slightly underestimating the true inclusion volume.
Merouche, Samir; Allard, Louise; Montagnon, Emmanuel; Soulez, Gilles; Bigras, Pascal; Cloutier, Guy
2016-01-01
Locating and evaluating the length and severity of a stenosis is very important for planning adequate treatment of peripheral arterial disease (PAD). Conventional ultrasound (US) examination cannot provide maps of entire lower limb arteries in 3-D. We propose a prototype 3D-US robotic system with B-mode images, which is nonionizing, noninvasive, and is able to track and reconstruct a continuous segment of the lower limb arterial tree between the groin and the knee. From an initialized cross-sectional view of the vessel, automatic tracking was conducted followed by 3D-US reconstructions evaluated using Hausdorff distance, cross-sectional area, and stenosis severity in comparison with 3-D reconstructions with computed tomography angiography (CTA). A mean Hausdorff distance of 0.97 ± 0.46 mm was found in vitro for 3D-US compared with 3D-CTA vessel representations. To evaluate the stenosis severity in vitro, 3D-US reconstructions gave errors of 3%-6% when compared with designed dimensions of the phantom, which are comparable to 3D-CTA reconstructions, with 4%-13% errors. The in vivo system's feasibility to reconstruct a normal femoral artery segment of a volunteer was also investigated. These results encourage further ergonomic developments to increase the robot's capacity to represent lower limb vessels in the clinical context.
NASA Astrophysics Data System (ADS)
Hossain, Md. Murad; AlMuhanna, Khalid; Zhao, Limin; Lal, Brajesh K.; Sikdar, Siddhartha
2014-03-01
3D segmentation of carotid plaque from ultrasound (US) images is challenging due to image artifacts and poor boundary definition. Semiautomatic segmentation algorithms for calculating vessel wall volume (VWV) have been proposed for the common carotid artery (CCA) but they have not been applied on plaques in the internal carotid artery (ICA). In this work, we describe a 3D segmentation algorithm that is robust to shadowing and missing boundaries. Our algorithm uses distance regularized level set method with edge and region based energy to segment the adventitial wall boundary (AWB) and lumen-intima boundary (LIB) of plaques in the CCA, ICA and external carotid artery (ECA). The algorithm is initialized by manually placing points on the boundary of a subset of transverse slices with an interslice distance of 4mm. We propose a novel user defined stopping surface based energy to prevent leaking of evolving surface across poorly defined boundaries. Validation was performed against manual segmentation using 3D US volumes acquired from five asymptomatic patients with carotid stenosis using a linear 4D probe. A pseudo gold-standard boundary was formed from manual segmentation by three observers. The Dice similarity coefficient (DSC), Hausdor distance (HD) and modified HD (MHD) were used to compare the algorithm results against the pseudo gold-standard on 1205 cross sectional slices of 5 3D US image sets. The algorithm showed good agreement with the pseudo gold standard boundary with mean DSC of 93.3% (AWB) and 89.82% (LIB); mean MHD of 0.34 mm (AWB) and 0.24 mm (LIB); mean HD of 1.27 mm (AWB) and 0.72 mm (LIB). The proposed 3D semiautomatic segmentation is the first step towards full characterization of 3D plaque progression and longitudinal monitoring.
Angelini, Elsa D; Homma, Shunichi; Pearson, Gregory; Holmes, Jeffrey W; Laine, Andrew F
2005-09-01
Among screening modalities, echocardiography is the fastest, least expensive and least invasive method for imaging the heart. A new generation of three-dimensional (3-D) ultrasound (US) technology has been developed with real-time 3-D (RT3-D) matrix phased-array transducers. These transducers allow interactive 3-D visualization of cardiac anatomy and fast ventricular volume estimation without tomographic interpolation as required with earlier 3-D US acquisition systems. However, real-time acquisition speed is performed at the cost of decreasing spatial resolution, leading to echocardiographic data with poor definition of anatomical structures and high levels of speckle noise. The poor quality of the US signal has limited the acceptance of RT3-D US technology in clinical practice, despite the wealth of information acquired by this system, far greater than with any other existing echocardiography screening modality. We present, in this work, a clinical study for segmentation of right and left ventricular volumes using RT3-D US. A preprocessing of the volumetric data sets was performed using spatiotemporal brushlet denoising, as presented in previous articles Two deformable-model segmentation methods were implemented in 2-D using a parametric formulation and in 3-D using an implicit formulation with a level set implementation for extraction of endocardial surfaces on denoised RT3-D US data. A complete and rigorous validation of the segmentation methods was carried out for quantification of left and right ventricular volumes and ejection fraction, including comparison of measurements with cardiac magnetic resonance imaging as the reference. Results for volume and ejection fraction measurements report good performance of quantification of cardiac function on RT3-D data compared with magnetic resonance imaging with better performance of semiautomatic segmentation methods than with manual tracing on the US data.
Three dimensional strained semiconductors
Voss, Lars; Conway, Adam; Nikolic, Rebecca J.; Leao, Cedric Rocha; Shao, Qinghui
2016-11-08
In one embodiment, an apparatus includes a three dimensional structure comprising a semiconductor material, and at least one thin film in contact with at least one exterior surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the three dimensional structure. In another embodiment, a method includes forming a three dimensional structure comprising a semiconductor material, and depositing at least one thin film on at least one surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the structure.
NASA Astrophysics Data System (ADS)
Huang, C. H.; Hsieh, C. H.; Lee, J. D.; Huang, W. C.; Lee, S. T.; Wu, C. T.; Sun, Y. N.; Wu, Y. T.
2012-08-01
With the combined view on the physical space and the medical imaging data, augmented reality (AR) visualization can provide perceptive advantages during image-guided surgery (IGS). However, the imaging data are usually captured before surgery and might be different from the up-to-date one due to natural shift of soft tissues. This study presents an AR-enhanced IGS system which is capable to correct the movement of soft tissues from the pre-operative CT images by using intra-operative ultrasound images. First, with reconstructing 2-D free-hand ultrasound images to 3-D volume data, the system applies a Mutual-Information based registration algorithm to estimate the deformation between pre-operative and intra-operative ultrasound images. The estimated deformation transform describes the movement of soft tissues and is then applied to the pre-operative CT images which provide high-resolution anatomical information. As a result, the system thus displays the fusion of the corrected CT images or the real-time 2-D ultrasound images with the patient in the physical space through a head mounted display device, providing an immersive augmented-reality environment. For the performance validation of the proposed system, a brain phantom was utilized to simulate brain-shift scenario. Experimental results reveal that when the shift of an artificial tumor is from 5mm ~ 12mm, the correction rates can be improved from 32% ~ 45% to 87% ~ 95% by using the proposed system.
Benacerraf, B R; Sadow, P M; Barnewolt, C E; Estroff, J A; Benson, C
2006-05-01
We present a case of Fryns' syndrome diagnosed prenatally using three-dimensional (3D) ultrasonography and magnetic resonance imaging (MRI). A cleft of the soft palate was diagnosed using 3D thick-slice ultrasonography. Other sonographic findings included a right diaphragmatic hernia, enlarged echogenic kidneys and severe polyhydramnios. The detection of the cleft palate was instrumental in suggesting the diagnosis of Fryns' syndrome in a fetus which also had a diaphragmatic hernia. These findings were also demonstrated with prenatal MRI. The technique of imaging the soft palate en face using a thick-slice technique is presented.
Wu, Lin; Lin, Liangjun; Qin, Yi-Xian
2015-01-01
Concerns over the use of autografts or allografts have necessitated the development of biomaterials for bone regeneration. Various studies have been performed to optimize the cultivation of osteogenic cells using osteoconductive porous scaffolds. The aim of this study was to evaluate the osteogenic efficiency of bone cell ingrowth, proliferation, and early differentiation in a silicon carbide (SiC) porous ceramic scaffold promoted with low-intensity pulsed ultrasound. MC3T3-E1 mouse preosteoblasts were seeded onto scaffolds and cultured for 4 and 7 days with daily of 20-min ultrasound treatment. The cells were evaluated for cell attachment, morphology, viability, ingrowth depth, volumetric proliferation, and early differentiation. After 4 and 7 days of culture and ultrasound exposure, the cell density was higher in the ultrasound-treated group compared with the sham-treated group on SiC scaffolds. The cell ingrowth depths inside the SiC scaffolds were 149.2±27.3 μm at 1 day, 310.1±12.6 μm for the ultrasound-treated group and 248.0±19.7 μm for the sham control at 4 days, and 359.6±18.5 μm for the ultrasound-treated group and 280.0±17.7 μm for the sham control at 7 days. They were significantly increased, that is, 25% (p=0.0029) and 28% (p=0.0008) increase, respectively, with ultrasound radiation force as compared with those in sham control at 4 and 7 days postseeding. The dsDNA contents were 583.5±19.1 ng/scaffold at 1 day, 2749.9±99.9 ng/scaffold for the ultrasound-treated group and 2514.9±114.7 ng/scaffold for the sham control at 4 days, and 3582.3±325.3 ng/scaffold for the ultrasound-treated group and 2825.7±134.3 ng/scaffold for the sham control at 7 days. There was a significant difference in the dsDNA content between the ultrasound- and sham-treated groups at 4 and 7 days. The ultrasound-treated group with the SiC construct showed a 9% (p=0.00029) and 27% (p=0.00017) increase in the average dsDNA content at 4 and 7 days over
Lin, Liangjun
2015-01-01
Concerns over the use of autografts or allografts have necessitated the development of biomaterials for bone regeneration. Various studies have been performed to optimize the cultivation of osteogenic cells using osteoconductive porous scaffolds. The aim of this study was to evaluate the osteogenic efficiency of bone cell ingrowth, proliferation, and early differentiation in a silicon carbide (SiC) porous ceramic scaffold promoted with low-intensity pulsed ultrasound. MC3T3-E1 mouse preosteoblasts were seeded onto scaffolds and cultured for 4 and 7 days with daily of 20-min ultrasound treatment. The cells were evaluated for cell attachment, morphology, viability, ingrowth depth, volumetric proliferation, and early differentiation. After 4 and 7 days of culture and ultrasound exposure, the cell density was higher in the ultrasound-treated group compared with the sham-treated group on SiC scaffolds. The cell ingrowth depths inside the SiC scaffolds were 149.2±27.3 μm at 1 day, 310.1±12.6 μm for the ultrasound-treated group and 248.0±19.7 μm for the sham control at 4 days, and 359.6±18.5 μm for the ultrasound-treated group and 280.0±17.7 μm for the sham control at 7 days. They were significantly increased, that is, 25% (p=0.0029) and 28% (p=0.0008) increase, respectively, with ultrasound radiation force as compared with those in sham control at 4 and 7 days postseeding. The dsDNA contents were 583.5±19.1 ng/scaffold at 1 day, 2749.9±99.9 ng/scaffold for the ultrasound-treated group and 2514.9±114.7 ng/scaffold for the sham control at 4 days, and 3582.3±325.3 ng/scaffold for the ultrasound-treated group and 2825.7±134.3 ng/scaffold for the sham control at 7 days. There was a significant difference in the dsDNA content between the ultrasound- and sham-treated groups at 4 and 7 days. The ultrasound-treated group with the SiC construct showed a 9% (p=0.00029) and 27% (p=0.00017) increase in the average dsDNA content at 4 and 7 days over
McDannold, Nathan; Park, Eun-Joo; Mei, Chang-Sheng; Zadicario, Eyal; Jolesz, Ferenc
2010-09-01
Transcranial MR-guided focused ultrasound (TcMRgFUS) provides a potential noninvasive alternative to surgical resection and for other treatments for brain disorders. Use of low-frequency ultrasound provides several advantages for TcMRgFUS, but is potentially limited by reflection and standing wave effects that may cause secondary hotspots within the skull cavity. The purpose of this work was to use volumetric magnetic resonance temperature imaging (MRTI) and ex vivo human skulls filled with tissue-mimicking phantom material to search for heating distant from the focal point that may occur during sonication with a TcMRgFUS system as a result of reflections or standing wave effects. Heating during 120-s sonications was monitored within the entire skull volume for 12 different locations in two different skulls. The setup used a hemispheric array operating at 220 kHz. Multiple sonications were delivered at each location while varying the MRTI slice positions to provide full coverage of the skull cavity. An automated routine was used evaluate the MRTI to detect voxel regions that appeared to be heated by ultrasound. No secondary hotspots with a temperature rise of 15% or more of the focal heating were found. The MRTI noise level prevented the identification of possible hotspots with a lower temperature rise. These results suggest that significant secondary heating by this TcMRgFUS system at points distant from the focal point are not common.
Three-dimensional metamaterials
Burckel, David Bruce
2012-06-12
A fabrication method is capable of creating canonical metamaterial structures arrayed in a three-dimensional geometry. The method uses a membrane suspended over a cavity with predefined pattern as a directional evaporation mask. Metallic and/or dielectric material can be evaporated at high vacuum through the patterned membrane to deposit resonator structures on the interior walls of the cavity, thereby providing a unit cell of micron-scale dimension. The method can produce volumetric metamaterial structures comprising layers of such unit cells of resonator structures.
Three dimensional quantum chromodynamics
NASA Astrophysics Data System (ADS)
Ferretti, G.; Rajeev, S. G.; Yang, Z.
1992-02-01
The subject of this talk is the study of the low energy behavior of three (2+1) dimensional Quantum Chromodynamics. We show the existence of a phase where parity is unbroken and the flavor group U(2n) is broken into a subgroup U(n)×U(n). We derive the low energy effective action for the theory and show that it has solitonic excitations with Fermi statistic, to be identified with the three dimensional ``baryon''. Finally, we study the current algebra for this effective action and we find a co-homologically nontrivial generalization of Kac-Moody algebras to three dimension.
Three Dimensional Dirac Semimetals
NASA Astrophysics Data System (ADS)
Zaheer, Saad
2014-03-01
Dirac points on the Fermi surface of two dimensional graphene are responsible for its unique electronic behavior. One can ask whether any three dimensional materials support similar pseudorelativistic physics in their bulk electronic spectra. This possibility has been investigated theoretically and is now supported by two successful experimental demonstrations reported during the last year. In this talk, I will summarize the various ways in which Dirac semimetals can be realized in three dimensions with primary focus on a specific theory developed on the basis of representations of crystal spacegroups. A three dimensional Dirac (Weyl) semimetal can appear in the presence (absence) of inversion symmetry by tuning parameters to the phase boundary separating a bulk insulating and a topological insulating phase. More generally, we find that specific rules governing crystal symmetry representations of electrons with spin lead to robust Dirac points at high symmetry points in the Brillouin zone. Combining these rules with microscopic considerations identifies six candidate Dirac semimetals. Another method towards engineering Dirac semimetals involves combining crystal symmetry and band inversion. Several candidate materials have been proposed utilizing this mechanism and one of the candidates has been successfully demonstrated as a Dirac semimetal in two independent experiments. Work carried out in collaboration with: Julia A. Steinberg, Steve M. Young, J.C.Y. Teo, C.L. Kane, E.J. Mele and Andrew M. Rappe.
NASA Technical Reports Server (NTRS)
Roth, Don J.; Kautz, Harold E.; Abel, Phillip B.; Whalen, Mike F.; Hendricks, J. Lynne; Bodis, James R.
2000-01-01
Surface topography, which significantly affects the performance of many industrial components, is normally measured with diamond-tip profilometry over small areas or with optical scattering methods over larger areas. To develop air-coupled surface profilometry, the NASA Glenn Research Center at Lewis Field initiated a Space Act Agreement with Sonix, Inc., through two Glenn programs, the Advanced High Temperature Engine Materials Program (HITEMP) and COMMTECH. The work resulted in quantitative surface topography profiles obtained using only high-frequency, focused ultrasonic pulses in air. The method is nondestructive, noninvasive, and noncontact, and it does not require light-reflective surfaces. Air surface profiling may be desirable when diamond-tip or laserbased methods are impractical, such as over large areas, when a significant depth range is required, or for curved surfaces. When the configuration is optimized, the method is reasonably rapid and all the quantitative analysis facilities are online, including two- and three-dimensional visualization, extreme value filtering (for faulty data), and leveling.
Lindsey, Brooks D.; Nicoletto, Heather A.; Bennett, Ellen R.; Laskowitz, Daniel T.; Smith, Stephen W.
2013-01-01
With stroke currently the second-leading cause of death globally, and 87% of all strokes classified as ischemic, the development of a fast, accessible, cost-effective approach for imaging occlusive stroke could have a significant impact on healthcare outcomes and costs. While clinical examination and standard CT alone do not provide adequate information for understanding the complex temporal events that occur during an ischemic stroke, ultrasound imaging is well-suited to the task of examining blood flow dynamics in real-time and may allow for localization of a clot. A prototype bilateral 3D ultrasound imaging system utilizing two matrix array probes on either side of the head allows for correction of skull-induced aberration throughout two entire phased array imaging volumes. We investigated the feasibility of applying this custom correction technique in 5 healthy volunteers with Definity® microbubble contrast enhancement. Subjects were scanned simultaneously via both temporal acoustic windows in 3D color flow mode. The number of color flow voxels above a common threshold increased due to aberration correction in 5/5 subjects, with a mean increase of 33.9%. The percentage of large arteries visualized in 3D color Doppler imaging increased from 46% without aberration correction to 60% with aberration correction. PMID:24239360
Three dimensional interactive display
NASA Technical Reports Server (NTRS)
Vranish, John M. (Inventor)
2005-01-01
A three-dimensional (3-D) interactive display and method of forming the same, includes a transparent capaciflector (TC) camera formed on a transparent shield layer on the screen surface. A first dielectric layer is formed on the shield layer. A first wire layer is formed on the first dielectric layer. A second dielectric layer is formed on the first wire layer. A second wire layer is formed on the second dielectric layer. Wires on the first wire layer and second wire layer are grouped into groups of parallel wires with a turnaround at one end of each group and a sensor pad at the opposite end. An operational amplifier is connected to each of the sensor pads and the shield pad biases the pads and receives a signal from connected sensor pads in response to intrusion of a probe. The signal is proportional to probe location with respect to the monitor screen.
Three-Dimensional Complex Variables
NASA Technical Reports Server (NTRS)
Martin, E. Dale
1988-01-01
Report presents new theory of analytic functions of three-dimensional complex variables. While three-dimensional system subject to more limitations and more difficult to use than the two-dimensional system, useful in analysis of three-dimensional fluid flows, electrostatic potentials, and other phenomena involving harmonic functions.
Zhang, Edward; Laufer, Jan; Beard, Paul
2008-02-01
A multiwavelength backward-mode planar photoacoustic scanner for 3D imaging of soft tissues to depths of several millimeters with a spatial resolution in the tens to hundreds of micrometers range is described. The system comprises a tunable optical parametric oscillator laser system that provides nanosecond laser pulses between 600 and 1200 nm for generating the photoacoustic signals and an optical ultrasound mapping system based upon a Fabry-Perot polymer film sensor for detecting them. The system enables photoacoustic signals to be mapped in 2D over a 50 mm diameter aperture in steps of 10 microm with an optically defined element size of 64 microm. Two sensors were used, one with a 22 microm thick polymer film spacer and the other with a 38 mum thick spacer providing -3 dB acoustic bandwidths of 39 and 22 MHz, respectively. The measured noise equivalent pressure of the 38 microm sensor was 0.21 kPa over a 20 MHz measurement bandwidth. The instrument line-spread function (LSF) was measured as a function of position and the minimum lateral and vertical LSFs found to be 38 and 15 microm, respectively. To demonstrate the ability of the system to provide high-resolution 3D images, a range of absorbing objects were imaged. Among these was a blood vessel phantom that comprised a network of blood filled tubes of diameters ranging from 62 to 300 microm immersed in an optically scattering liquid. In addition, to demonstrate the applicability of the system to spectroscopic imaging, a phantom comprising tubes filled with dyes of different spectral characteristics was imaged at a range of wavelengths. It is considered that this type of instrument may provide a practicable alternative to piezoelectric-based photoacoustic systems for high-resolution structural and functional imaging of the skin microvasculature and other superficial structures.
Three dimensional Dirac semimetals
NASA Astrophysics Data System (ADS)
Zaheer, Saad
We extend the physics of graphene to three dimensional systems by showing that Dirac points can exist on the Fermi surface of realistic materials in three dimensions. Many of the exotic electronic properties of graphene can be ascribed to the pseudorelativistic behavior of its charge carriers due to two dimensional Dirac points on the Fermi surface. We show that certain nonsymmorphic spacegroups exhibit Dirac points among the irreducible representations of the appropriate little group at high symmetry points on the surface of the Brillouin zone. We provide a list of all Brillouin zone momenta in the 230 spacegroups that can host Dirac points. We describe microscopic considerations necessary to design materials in one of the candidate spacegroups such that the Dirac point appears at the Fermi energy without any additional non-Dirac-like Fermi pockets. We use density functional theory based methods to propose six new Dirac semimetals: BiO 2 and SbO2 in the beta-cristobalite lattice (spacegroup 227), and BiCaSiO4, BiMgSiO4, BiAlInO 4, and BiZnSiO4 in the distorted spinels lattice (spacegroup 74). Additionally we derive effective Dirac Hamiltonians given group representative operators as well as tight binding models incorporating spin-orbit coupling. Finally we study the Fermi surface of zincblende (spacegroup 216) HgTe which is effectively point-like at Gamma in the Brillouin zone and exhibits accidental degeneracies along a threefold rotation axis. Whereas compressive strain gaps the band structure into a topological insulator, tensile strain shifts the accidental degeneracies away from Gamma and enlarges the Fermi surface. States on the Fermi surface exhibit nontrivial spin texture marked by winding of spins around the threefold rotation axis and by spin vortices indicating a change in the winding number. This is confirmed by microscopic calculations performed in tensile strained HgTe and Hg0.5Zn 0.5 Te as well as k.p theory. We conclude with a summary of recent
Three-dimensional echocardiographic technology.
Salgo, Ivan S
2007-05-01
This article addresses the current state of the art of technology in three-dimensional echocardiography as it applies to transducer design, beam forming, display, and quantification. Because three-dimensional echocardiography encompasses many technical and clinical areas, this article reviews its strengths and limitations and concludes with an analysis of what to use when.
Three-dimensional marginal separation
NASA Technical Reports Server (NTRS)
Duck, Peter W.
1988-01-01
The three dimensional marginal separation of a boundary layer along a line of symmetry is considered. The key equation governing the displacement function is derived, and found to be a nonlinear integral equation in two space variables. This is solved iteratively using a pseudo-spectral approach, based partly in double Fourier space, and partly in physical space. Qualitatively, the results are similar to previously reported two dimensional results (which are also computed to test the accuracy of the numerical scheme); however quantitatively the three dimensional results are much different.
Three-dimensional stellarator codes
Garabedian, P. R.
2002-01-01
Three-dimensional computer codes have been used to develop quasisymmetric stellarators with modular coils that are promising candidates for a magnetic fusion reactor. The mathematics of plasma confinement raises serious questions about the numerical calculations. Convergence studies have been performed to assess the best configurations. Comparisons with recent data from large stellarator experiments serve to validate the theory. PMID:12140367
Three dimensional colorimetric assay assemblies
Charych, D.; Reichart, A.
2000-06-27
A direct assay is described using novel three-dimensional polymeric assemblies which change from a blue to red color when exposed to an analyte, in one case a flu virus. The assemblies are typically in the form of liposomes which can be maintained in a suspension, and show great intensity in their color changes. Their method of production is also described.
Three dimensional colorimetric assay assemblies
Charych, Deborah; Reichart, Anke
2000-01-01
A direct assay is described using novel three-dimensional polymeric assemblies which change from a blue to red color when exposed to an analyte, in one case a flu virus. The assemblies are typically in the form of liposomes which can be maintained in a suspension, and show great intensity in their color changes. Their method of production is also described.
Creating Three-Dimensional Scenes
ERIC Educational Resources Information Center
Krumpe, Norm
2005-01-01
Persistence of Vision Raytracer (POV-Ray), a free computer program for creating photo-realistic, three-dimensional scenes and a link for Mathematica users interested in generating POV-Ray files from within Mathematica, is discussed. POV-Ray has great potential in secondary mathematics classrooms and helps in strengthening students' visualization…
Three-Dimensional Lissajous Figures.
ERIC Educational Resources Information Center
D'Mura, John M.
1989-01-01
Described is a mechanically driven device for generating three-dimensional harmonic space figures with different frequencies and phase angles on the X, Y, and Z axes. Discussed are apparatus, viewing stereo pairs, equations of motion, and using space figures in classroom. (YP)
Three-dimensional perspective visualization
NASA Technical Reports Server (NTRS)
Hussey, Kevin
1991-01-01
It was demonstrated that image processing computer graphic techniques can provide an effective means of physiographic analysis of remotely sensed regions through the use of three-dimensional perspective rendering. THe methods used to simulate and animate three-dimensional surfaces from two-dimensional imagery and digital elevation models are explained. A brief historic look at JPL's efforts in this field and several examples of animations, illustrating the evolution of these techniques from 1985, are shown. JPL's current research in this area is discussed along with examples of technology transfer and potential commercial application. The software is part of the VICAR (Video Image Communication and Retrieval) image processing system which was developed at the Multimission Image Processing Laboratory of JPL.
Quasicrystalline three-dimensional foams
NASA Astrophysics Data System (ADS)
Cox, S. J.; Graner, F.; Mosseri, R.; Sadoc, J.-F.
2017-03-01
We present a numerical study of quasiperiodic foams, in which the bubbles are generated as duals of quasiperiodic Frank–Kasper phases. These foams are investigated as potential candidates to the celebrated Kelvin problem for the partition of three-dimensional space with equal volume bubbles and minimal surface area. Interestingly, one of the computed structures falls close to (but still slightly above) the best known Weaire–Phelan periodic candidate. In addition we find a correlation between the normalized bubble surface area and the root mean squared deviation of the number of faces, giving an additional clue to understanding the main geometrical ingredients driving the Kelvin problem.
Three-dimensional vortex methods
Greengard, C.A.
1984-08-01
Three-dimensional vortex methods for the computation of incompressible fluid flow are presented from a unified point of view. Reformulations of the filament method and of the method of Beale and Majda show them to be very similar algorithms; in both of them, the vorticity is evaluated by a discretization of the spatial derivative of the flow map. The fact that the filament method, the one which is most often used in practice, can be formulated as a version of the Beale and Majda algorithm in a curved coordinate system is used to give a convergence theorem for the filament method. The method of Anderson is also discussed, in which vorticity is evaluated by the exact differentiation of the approximate velocity field. It is shown that, in the inviscid version of this algorithm, each approximate vector of vorticity remains tangent to a material curve moving with the computed flow, with magnitude proportional to the stretching of this vortex line. This remains true even when time discretization is taken into account. It is explained that the expanding core vortex method converges to a system of equations different from the Navier-Stokes equations. Computations with the filament method of the inviscid interaction of two vortex rings are reported, both with single filaments in each ring and with a fully three-dimensional discretization of vorticity. The dependence on parameters is discussed, and convergence of the computed solutions is observed. 36 references, 4 figures.
Ultrasound guided spine needle insertion
NASA Astrophysics Data System (ADS)
Chen, Elvis C. S.; Mousavi, Parvin; Gill, Sean; Fichtinger, Gabor; Abolmaesumi, Purang
2010-02-01
An ultrasound (US) guided, CT augmented, spine needle insertion navigational system is introduced. The system consists of an electromagnetic (EM) sensor, an US machine, and a preoperative CT volume of the patient anatomy. Three-dimensional (3D) US volume is reconstructed intraoperatively from a set of two-dimensional (2D) freehand US slices, and is coregistered with the preoperative CT. This allows the preoperative CT volume to be used in the intraoperative clinical coordinate. The spatial relationship between the patient anatomy, surgical tools, and the US transducer are tracked using the EM sensor, and are displayed with respect to the CT volume. The pose of the US transducer is used to interpolate the CT volume, providing the physician with a 2D "x-ray vision" to guide the needle insertion. Many of the system software components are GPU-accelerated, allowing real-time performance of the guidance system in a clinical setting.
Three-dimensional display technologies.
Geng, Jason
2013-01-01
The physical world around us is three-dimensional (3D), yet traditional display devices can show only two-dimensional (2D) flat images that lack depth (i.e., the third dimension) information. This fundamental restriction greatly limits our ability to perceive and to understand the complexity of real-world objects. Nearly 50% of the capability of the human brain is devoted to processing visual information [Human Anatomy & Physiology (Pearson, 2012)]. Flat images and 2D displays do not harness the brain's power effectively. With rapid advances in the electronics, optics, laser, and photonics fields, true 3D display technologies are making their way into the marketplace. 3D movies, 3D TV, 3D mobile devices, and 3D games have increasingly demanded true 3D display with no eyeglasses (autostereoscopic). Therefore, it would be very beneficial to readers of this journal to have a systematic review of state-of-the-art 3D display technologies.
Three-dimensional coil inductor
Bernhardt, Anthony F.; Malba, Vincent
2002-01-01
A three-dimensional coil inductor is disclosed. The inductor includes a substrate; a set of lower electrically conductive traces positioned on the substrate; a core placed over the lower traces; a set of side electrically conductive traces laid on the core and the lower traces; and a set of upper electrically conductive traces attached to the side traces so as to form the inductor. Fabrication of the inductor includes the steps of forming a set of lower traces on a substrate; positioning a core over the lower traces; forming a set of side traces on the core; connecting the side traces to the lower traces; forming a set of upper traces on the core; and connecting the upper traces to the side traces so as to form a coil structure.
Three-dimensional aromatic networks.
Toyota, Shinji; Iwanaga, Tetsuo
2014-01-01
Three-dimensional (3D) networks consisting of aromatic units and linkers are reviewed from various aspects. To understand principles for the construction of such compounds, we generalize the roles of building units, the synthetic approaches, and the classification of networks. As fundamental compounds, cyclophanes with large aromatic units and aromatic macrocycles with linear acetylene linkers are highlighted in terms of transannular interactions between aromatic units, conformational preference, and resolution of chiral derivatives. Polycyclic cage compounds are constructed from building units by linkages via covalent bonds, metal-coordination bonds, or hydrogen bonds. Large cage networks often include a wide range of guest species in their cavity to afford novel inclusion compounds. Topological isomers consisting of two or more macrocycles are formed by cyclization of preorganized species. Some complicated topological networks are constructed by self-assembly of simple building units.
Three-dimensional vortex methods
NASA Astrophysics Data System (ADS)
Greengard, C. A.
1984-08-01
Reformulations of the filament method and of the method of Beale and Majda show them to be very similar algorithms. The method of Anderson in which vorticity is evaluated by the exact differentiation of the approximate velocity field is discussed. It is shown that, in the inviscid version of this algorithm, each approximate vector of vorticity remains tangent to a material curve moving with the computed flow, with magnitude proportional to the stretching of this vortex line. It is explained that the expanding core vortex method converges to a system of equations different from the Navier-Stokes equations. Computations with the filament method of the inviscid interaction of two vortex rings are reported, both with single filaments in each ring and with a fully three-dimensional discretization of vorticity. The dependence on parameters is discussed, and convergence of the computed solutions is observed.
Three dimensional magnetic abacus memory
Zhang, ShiLei; Zhang, JingYan; Baker, Alexander A.; Wang, ShouGuo; Yu, GuangHua; Hesjedal, Thorsten
2014-01-01
Stacking nonvolatile memory cells into a three-dimensional matrix represents a powerful solution for the future of magnetic memory. However, it is technologically challenging to access the data in the storage medium if large numbers of bits are stacked on top of each other. Here we introduce a new type of multilevel, nonvolatile magnetic memory concept, the magnetic abacus. Instead of storing information in individual magnetic layers, thereby having to read out each magnetic layer separately, the magnetic abacus adopts a new encoding scheme. It is inspired by the idea of second quantisation, dealing with the memory state of the entire stack simultaneously. Direct read operations are implemented by measuring the artificially engineered ‘quantised' Hall voltage, each representing a count of the spin-up and spin-down layers in the stack. This new memory system further allows for both flexible scaling of the system and fast communication among cells. The magnetic abacus provides a promising approach for future nonvolatile 3D magnetic random access memory. PMID:25146338
Three-dimensional colloidal lithography.
Nagai, Hironori; Poteet, Austen; Zhang, Xu A; Chang, Chih-Hao
2017-03-24
Light interactions with colloidal particles can generate a variety of complex three-dimensional (3D) intensity patterns, which can be utilized for nanolithography. The study of particle-light interactions can add more types of intensity patterns by manipulating key factors. Here we investigate a novel 3D nanolithography technique using colloidal particles under two-beam coherent illuminations. The fabricated 3D nanostructures are hollow, nested within periodic structures, and possess multiple chamber geometry. The effects of incident angles and particle size on the fabricated nanostructures were examined. The relative phase shift between particle position and interference pattern is identified as another significant parameter influencing the resultant nanostructures. A numerical model has been developed to show the evolution of nanostructure geometry with phase shifts, and experimental studies confirm the simulation results. Through the introduction of single colloidal particles, the fabrication capability of Lloyd's mirror interference can now be extended to fabrication of 3D nanostructure with complex shell geometry. The fabricated hollow nanostructures with grating background could find potential applications in the area of photonics, drug delivery, and nanofluidics.
Three-dimensional laser microvision.
Shimotahira, H; Iizuka, K; Chu, S C; Wah, C; Costen, F; Yoshikuni, Y
2001-04-10
A three-dimensional (3-D) optical imaging system offering high resolution in all three dimensions, requiring minimum manipulation and capable of real-time operation, is presented. The system derives its capabilities from use of the superstructure grating laser source in the implementation of a laser step frequency radar for depth information acquisition. A synthetic aperture radar technique was also used to further enhance its lateral resolution as well as extend the depth of focus. High-speed operation was made possible by a dual computer system consisting of a host and a remote microcomputer supported by a dual-channel Small Computer System Interface parallel data transfer system. The system is capable of operating near real time. The 3-D display of a tunneling diode, a microwave integrated circuit, and a see-through image taken by the system operating near real time are included. The depth resolution is 40 mum; lateral resolution with a synthetic aperture approach is a fraction of a micrometer and that without it is approximately 10 mum.
Three-Dimensional Laser Microvision
NASA Astrophysics Data System (ADS)
Shimotahira, Hiroshi; Iizuka, Keigo; Chu, Sun-Chun; Wah, Christopher; Costen, Furnie; Yoshikuni, Yuzo
2001-04-01
A three-dimensional (3-D) optical imaging system offering high resolution in all three dimensions, requiring minimum manipulation and capable of real-time operation, is presented. The system derives its capabilities from use of the superstructure grating laser source in the implementation of a laser step frequency radar for depth information acquisition. A synthetic aperture radar technique was also used to further enhance its lateral resolution as well as extend the depth of focus. High-speed operation was made possible by a dual computer system consisting of a host and a remote microcomputer supported by a dual-channel Small Computer System Interface parallel data transfer system. The system is capable of operating near real time. The 3-D display of a tunneling diode, a microwave integrated circuit, and a see-through image taken by the system operating near real time are included. The depth resolution is 40 m; lateral resolution with a synthetic aperture approach is a fraction of a micrometer and that without it is approximately 10 m.
Three-dimensional colloidal lithography
NASA Astrophysics Data System (ADS)
Nagai, Hironori; Poteet, Austen; Zhang, Xu A.; Chang, Chih-Hao
2017-03-01
Light interactions with colloidal particles can generate a variety of complex three-dimensional (3D) intensity patterns, which can be utilized for nanolithography. The study of particle–light interactions can add more types of intensity patterns by manipulating key factors. Here we investigate a novel 3D nanolithography technique using colloidal particles under two-beam coherent illuminations. The fabricated 3D nanostructures are hollow, nested within periodic structures, and possess multiple chamber geometry. The effects of incident angles and particle size on the fabricated nanostructures were examined. The relative phase shift between particle position and interference pattern is identified as another significant parameter influencing the resultant nanostructures. A numerical model has been developed to show the evolution of nanostructure geometry with phase shifts, and experimental studies confirm the simulation results. Through the introduction of single colloidal particles, the fabrication capability of Lloyd’s mirror interference can now be extended to fabrication of 3D nanostructure with complex shell geometry. The fabricated hollow nanostructures with grating background could find potential applications in the area of photonics, drug delivery, and nanofluidics.
Three-dimensional display technologies
Geng, Jason
2014-01-01
The physical world around us is three-dimensional (3D), yet traditional display devices can show only two-dimensional (2D) flat images that lack depth (i.e., the third dimension) information. This fundamental restriction greatly limits our ability to perceive and to understand the complexity of real-world objects. Nearly 50% of the capability of the human brain is devoted to processing visual information [Human Anatomy & Physiology (Pearson, 2012)]. Flat images and 2D displays do not harness the brain’s power effectively. With rapid advances in the electronics, optics, laser, and photonics fields, true 3D display technologies are making their way into the marketplace. 3D movies, 3D TV, 3D mobile devices, and 3D games have increasingly demanded true 3D display with no eyeglasses (autostereoscopic). Therefore, it would be very beneficial to readers of this journal to have a systematic review of state-of-the-art 3D display technologies. PMID:25530827
Three dimensional identification card and applications
NASA Astrophysics Data System (ADS)
Zhou, Changhe; Wang, Shaoqing; Li, Chao; Li, Hao; Liu, Zhao
2016-10-01
Three dimensional Identification Card, with its three-dimensional personal image displayed and stored for personal identification, is supposed be the advanced version of the present two-dimensional identification card in the future [1]. Three dimensional Identification Card means that there are three-dimensional optical techniques are used, the personal image on ID card is displayed to be three-dimensional, so we can see three dimensional personal face. The ID card also stores the three-dimensional face information in its inside electronics chip, which might be recorded by using two-channel cameras, and it can be displayed in computer as three-dimensional images for personal identification. Three-dimensional ID card might be one interesting direction to update the present two-dimensional card in the future. Three-dimension ID card might be widely used in airport custom, entrance of hotel, school, university, as passport for on-line banking, registration of on-line game, etc...
Three-dimensional map construction.
Jenks, G F; Brown, D A
1966-11-18
Three-dimensional maps are useful tools which have been neglected for some time. They shouldbe more commonly used, and familiarity with the techniques discussed in this article should dispel any qualms anyone might ve about needing artistic talent to nstruct them. The saving in time esulting from the use of an anamorphoser provides a further incentive. The anamorphoser transformations discussed above were all prepared by using straight slits, oriented at right angles to each other and placed so that all planes of the elements were parallel to each other. It is possible to vary these conditions in an infinite number of ways and thereby produce nonparallel tranceformations. Some of these variations are illustrated in Fig. 10. All the illustrations in Fig. 10 are transformations of the planimetric weather map shown in Fig. 8A. The variations used for the maps of Fig. 10 are as follows. (A) All planes parallel, with a curved rear slit; (B) all planes parallel, with curved slits front and rear; ( C) all planes parallel, with S-shaped rear slit; (D) all planes parallel, with an undulating rear slit; (E) all planes parallel, with curved front and undulating rear slit; (F) plane of the original rotated on the horizontal axis-both slits curved; (G) plane of the original rotated on thevertical axis- both slits curved; (H) plane of the original rotated on the horizontal axis -both slits straight. These are only a few of the many transformations which can be made with an anamorphoser, butthey do point toward some interesting possibilities. For example, it appears that maps based onone projection might be altered to satisfy the coordinates of a completely different projection. Note, for example, the change of parallels from concave to convex curves (Figs. 8A and 10A) and the change from converging meridians to diverging meridians (Figs. 8A and l0G). Similarly, the grids of maps B, F, and H of Fig. 10 approximate projections which are quite different from the original. Other
Three Dimensional Illustrating--Three-Dimensional Vision and Deception of Sensibility
ERIC Educational Resources Information Center
Szállassy, Noémi; Gánóczy, Anita; Kriska, György
2009-01-01
The wide-spread digital photography and computer use gave the opportunity for everyone to make three-dimensional pictures and to make them public. The new opportunities with three-dimensional techniques give chance for the birth of new artistic photographs. We present in detail the biological roots of three-dimensional visualization, the phenomena…
Three-dimensional velocity measurements using LDA
NASA Astrophysics Data System (ADS)
Buchhave, Preben
The design requirements for and development of an LDA that measures the three components of the fluid velocity vector are described. The problems encountered in LDA measurements in highly turbulent flows, multivariate response, velocity bias, spatial resolution, temporal resolution, and dynamic range, are discussed. The use of the fringe and/or the reference beam methods to measure the three velocity components, and the use of color, frequency shift, and polarization to separate three velocity projections are examined. Consideration is given to the coordinate transformation, the presentation of three-dimensional LDA data, and the possibility of three-dimensional bias correction. Procedures for conducting three-dimensional LDA measurements are proposed.
Three Dimensional Optic Tissue Culture and Process
NASA Technical Reports Server (NTRS)
OConnor, Kim C. (Inventor); Spaulding, Glenn F. (Inventor); Goodwin, Thomas J. (Inventor); Aten, Laurie A. (Inventor); Francis, Karen M. (Inventor); Caldwell, Delmar R. (Inventor); Prewett, Tacey L. (Inventor); Fitzgerald, Wendy S. (Inventor)
1999-01-01
A process for artificially producing three-dimensional optic tissue has been developed. The optic cells are cultured in a bioireactor at low shear conditions. The tissue forms as normal, functional tissue grows with tissue organization and extracellular matrix formation.
Three dimensional optic tissue culture and process
NASA Technical Reports Server (NTRS)
Spaulding, Glenn F. (Inventor); Prewett, Tacey L. (Inventor); Goodwin, Thomas J. (Inventor); Francis, Karen M. (Inventor); Cardwell, Delmar R. (Inventor); Oconnor, Kim (Inventor); Fitzgerald, Wendy S. (Inventor); Aten, Laurie A. (Inventor)
1994-01-01
A process for artificially producing three-dimensional optic tissue has been developed. The optic cells are cultured in a bioreactor at low shear conditions. The tissue forms normal, functional tissue organization and extracellular matrix.
Three-dimensional motion measurements using feature tracking.
Kuo, Johnny; von Ramm, Olaf T
2008-04-01
Feature tracking was developed to efficiently compute motion measurements from volumetric ultrasound images. Prior studies have demonstrated the motion magnitude accuracy and computation speed of feature tracking. However, the previous feature tracking implementations were limited by performance of their calculations in rectilinear coordinates. Also, the previous feature tracking approaches did not fully explore the three dimensional (3- D) nature of volumetric image analysis or utilize the 3-D directional information from the tracking calculations. This study presents an improved feature tracking method which achieves further computation speed gains by performing all calculations in the native spherical coordinates of the 3-D ultrasound image. The novel method utilizes a statistical analysis of tracked directions of motion to achieve better rejection of false tracking matches. Results from in vitro tracking of a speckle target show that the new feature tracking method is significantly faster than correlation search and can accurately determine target motion magnitude and 3-D direction.
... your test will be done. Alternative Names Sonogram Images Abdominal ultrasound Ultrasound in pregnancy 17 week ultrasound ... urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows ...
Ultrasound is a type of imaging. It uses high-frequency sound waves to look at organs and ... liver, and other organs. During pregnancy, doctors use ultrasound to view the fetus. Unlike x-rays, ultrasound ...
Three-dimensional separation and reattachment
NASA Technical Reports Server (NTRS)
Peake, D. J.; Tobak, M.
1982-01-01
The separation of three dimensional turbulent boundary layers from the lee of flight vehicles at high angles of attack is investigated. The separation results in dominant, large scale, coiled vortex motions that pass along the body in the general direction of the free stream. In all cases of three dimensional flow separation and reattachment, the assumption of continuous vector fields of skin friction lines and external flow streamlines, coupled with simple laws of topology, provides a flow grammar whose elemental constituents are the singular points: the nodes, spiral nodes (foci), and saddles. The phenomenon of three dimensional separation may be construed as either a local or a global event, depending on whether the skin friction line that becomes a line of separation originates at a node or a saddle point.
Topology of three-dimensional separated flows
NASA Technical Reports Server (NTRS)
Tobak, M.; Peake, D. J.
1981-01-01
Based on the hypothesis that patterns of skin-friction lines and external streamlines reflect the properties of continuous vector fields, topology rules define a small number of singular points (nodes, saddle points, and foci) that characterize the patterns on the surface and on particular projections of the flow (e.g., the crossflow plane). The restricted number of singular points and the rules that they obey are considered as an organizing principle whose finite number of elements can be combined in various ways to connect together the properties common to all steady three dimensional viscous flows. Introduction of a distinction between local and global properties of the flow resolves an ambiguity in the proper definition of a three dimensional separated flow. Adoption of the notions of topological structure, structural stability, and bifurcation provides a framework to describe how three dimensional separated flows originate and succeed each other as the relevant parameters of the problem are varied.
Three-dimensional separation and reattachment
NASA Technical Reports Server (NTRS)
Peake, D. J.; Tobak, M.
1982-01-01
The separation of three dimensional turbulent boundary layers from the lee of flight vehicles at high angles of attack is investigated. The separation results in dominant, large scale, coiled vortex motions that pass along the body in the general direction of the free stream. In all cases of three dimensional flow separation and reattachment, the assumption of continuous vector fields of skin friction lines and external flow streamlines, coupled with simple laws of topology, provides a flow grammar whose elemental constituents are the singular points: the nodes, spiral nodes (foci), and saddles. The phenomenon of three dimensional separation may be constrained as either a local or a global event, depending on whether the skin friction line that becomes a line of separation originates at a node or a saddle point.
Vision in our three-dimensional world
2016-01-01
Many aspects of our perceptual experience are dominated by the fact that our two eyes point forward. Whilst the location of our eyes leaves the environment behind our head inaccessible to vision, co-ordinated use of our two eyes gives us direct access to the three-dimensional structure of the scene in front of us, through the mechanism of stereoscopic vision. Scientific understanding of the different brain regions involved in stereoscopic vision and three-dimensional spatial cognition is changing rapidly, with consequent influences on fields as diverse as clinical practice in ophthalmology and the technology of virtual reality devices. This article is part of the themed issue ‘Vision in our three-dimensional world’. PMID:27269595
Three-dimensional magnetic bubble memory system
NASA Technical Reports Server (NTRS)
Stadler, Henry L. (Inventor); Katti, Romney R. (Inventor); Wu, Jiin-Chuan (Inventor)
1994-01-01
A compact memory uses magnetic bubble technology for providing data storage. A three-dimensional arrangement, in the form of stacks of magnetic bubble layers, is used to achieve high volumetric storage density. Output tracks are used within each layer to allow data to be accessed uniquely and unambiguously. Storage can be achieved using either current access or field access magnetic bubble technology. Optical sensing via the Faraday effect is used to detect data. Optical sensing facilitates the accessing of data from within the three-dimensional package and lends itself to parallel operation for supporting high data rates and vector and parallel processing.
Three-dimensional displays and stereo vision.
Westheimer, Gerald
2011-08-07
Procedures for three-dimensional image reconstruction that are based on the optical and neural apparatus of human stereoscopic vision have to be designed to work in conjunction with it. The principal methods of implementing stereo displays are described. Properties of the human visual system are outlined as they relate to depth discrimination capabilities and achieving optimal performance in stereo tasks. The concept of depth rendition is introduced to define the change in the parameters of three-dimensional configurations for cases in which the physical disposition of the stereo camera with respect to the viewed object differs from that of the observer's eyes.
Fabrication of three dimensional microstructure fiber
NASA Astrophysics Data System (ADS)
Luo, Ying; Ma, Jie; Chen, Zhe; Lu, Huihui; Zhong, Yongchun
2015-05-01
A method of fabricating three dimensional (3D) microstructured fiber is presented. Polystyrene (PS) microspheres were coated around the surface of a micro-fiber through isothermal heating evaporation induced self-assembly method. Scanning electron microscopy (SEM) image shows that the colloidal crystal has continuous, uniform, and well-ordered face-centered cubic (FCC) structure, with [111] crystallographic direction normal to the surface of micro-fiber. This micro-fiber with three-dimensional photonic crystals structure is very useful in the applications of micro-fiber sensors or filters.
Three-dimensional stochastic vortex flows
NASA Astrophysics Data System (ADS)
Esposito, R.; Pulvirenti, M.
1989-08-01
It is well known that the dynamics of point vortices approximate, under suitable limits, the two-dimensional Euler flow for an ideal fluid. To find particle models for three-dimensional flows is a more intricate problem. A stochastic version of the algorithm introduced by Beale amd Maida (1982) for simulating the behavior of a three-dimensional Euler flow is introduced here, and convergence to the Navier-Stokes (NS) flow in R exp 3 is shown. The result is based on a stochastic Lagrangian picture of the NS equations.
Three-Dimensional Shallow Water Acoustics
2016-03-30
13-1-0026 entitled "Three- Dimensional Shallow Water Acoustics," Principal Investigator Dr. Ying-Tsong Lin. Sincerely, ;l1,J-Ju1 ~{hjM1...30/03/2016 01/01/2013-12/31/2015 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBERS Three-Dimensional Shallow Water Acoustics 5b, GRANT NUMBER N0001 4-13-1... Water Acoustics Dr. Ying-Tsong Lin Applied Ocean Physics and Engineering Department Woods Hole Oceanographic Institution, Woods Hole, MA 02543
Three-dimensional patterning methods and related devices
Putnam, Morgan C.; Kelzenberg, Michael D.; Atwater, Harry A.; Boettcher, Shannon W.; Lewis, Nathan S.; Spurgeon, Joshua M.; Turner-Evans, Daniel B.; Warren, Emily L.
2016-12-27
Three-dimensional patterning methods of a three-dimensional microstructure, such as a semiconductor wire array, are described, in conjunction with etching and/or deposition steps to pattern the three-dimensional microstructure.
Three-Dimensional Visualization of Particle Tracks.
ERIC Educational Resources Information Center
Julian, Glenn M.
1993-01-01
Suggests ways to bring home to the introductory physics student some of the excitement of recent discoveries in particle physics. Describes particle detectors and encourages the use of the Standard Model along with real images of particle tracks to determine three-dimensional views of tracks. (MVL)
Three Dimensional Display Of Meteorological Scientific Data
NASA Astrophysics Data System (ADS)
Grotch, Stanley L.
1988-01-01
Even a cursory reading of any daily newspaper shows that we are in the midst of a dramatic revolution in computer graphics. Virtually every day some new piece of hardware or software is announced, adding to the tools available to the working scientist. Three dimensional graphics form a significant part of this revolution having become virtually commonplace in advertising and on television.
Three-dimensional chiral photonic superlattices.
Thiel, M; Fischer, H; von Freymann, G; Wegener, M
2010-01-15
We investigate three-dimensional photonic superlattices composed of polymeric helices in various spatial checkerboard-like arrangements. Depending on the relative phase shift and handedness of the chiral building blocks, different circular-dichroism resonances appear or are suppressed. Samples corresponding to four different configurations are fabricated by direct laser writing. The measured optical transmittance spectra are in good agreement with numerical calculations.
Three-dimensional colorimetric assay assemblies
Charych, Deborah; Reichert, Anke
2001-01-01
A direct assay is described using novel three-dimensional polymeric assemblies which change from a blue to red color when exposed to an analyte, in one case a flue virus. The assemblies are typically in the form of liposomes which can be maintained in a suspension, and show great intensity in their color changes. Their method of production is also described.
Three-dimensional rf structure calculations
Cooper, R.K.; Browman, M.J.; Weiland, T.
1988-01-01
The calculation of three-dimensional rf structures is rapidly approaching adolescence, after having been in its infancy for the last four years. This paper will show the kinds of calculations that are currently being performed in the frequency domain and is a companion paper to one in which time-domain calculations are described. 13 refs., 14 figs.
Three-dimensional RF structure calculations
NASA Astrophysics Data System (ADS)
Cooper, R. K.; Browman, M. J.; Weiland, T.
1989-04-01
The calculation of three-dimensional rf structures is rapidly approaching adolescence, after having been in its infancy for the last four years. This paper will show the kinds of calculations that are currently being performed in the frequency domain and is a companion paper to one in which time-domain calculations are described.
Three dimensional reconnection in astrophysical plasmas
NASA Technical Reports Server (NTRS)
Spicer, D. S.
1990-01-01
Theoretical issues related to three-dimensional reconnection and its application to the space and astrophysical environment are reviewed. Consideration is given to the meaning of reconnection in three dimensions, the way in which periodic and nonperiodic magnetic topologies alter the physics of reconnections, and the effects of chaotic magnetic fields on the reconnection process.
[Three Dimensional Display in Nuclear Medicine].
Teraoka, Satomi; Souma, Tsutomu
2015-01-01
Imaging techniques to obtain a tomographic image in nuclear medicine such as PET and SPECT are widely used. It is necessary to interpreting all of the tomographic images obtained in order to accurately evaluate the individual lesion, whereas three dimensional display is often useful in order to overview and evaluate the feature of the entire lesion or disease such as the position, size and abnormal pattern. In Japan, the use of three dimensional image analysis workstation with an application of the co-registration and image fusion between the functional images such as PET or SPECT and anatomical images such as CT or MRI has been generalized. In addition, multimodality imaging system such as a PET/CT and SPECT/CT has been widespread. Therefore, it is expected to improve the diagnostic accuracy using three dimensionally image fusion to functional images with poor anatomical information. In this commentary, as an example of a three dimensional display that are commonly used in nuclear medicine examination in Japan, brain regions, cardiac region and bone and tumor region will be introduced separately.
Growing Three-Dimensional Cocultures Of Cells
NASA Technical Reports Server (NTRS)
Wolf, David A.; Goodwin, Thomas J.
1995-01-01
Laboratory process provides environmental conditions favoring simultaneous growth of cocultures of mammalian cells of more than one type. Cultures become three-dimensional tissuelike assemblies serving as organoid models of differentiation of cells. Process used, for example, to study growth of human colon cancers, starting from mixtures of normal colonic fibroblasts and partially differentiated colon adenocarcinoma cells.
Three-Dimensional Pointers for Stereoscopic Projection.
ERIC Educational Resources Information Center
Hayman, H. J. G.
1984-01-01
Because class size often limits student opportunity to handle individual models, teachers use stereoscopic projections to demonstrate structural features. Describes three-dimensional pointers for use with different projection systems so teachers can indicate a particular atom or bond to entire classes, avoiding the perspective problems inherent in…
Three-Dimensional Printing Surgical Applications
Griffin, Michelle F.; Butler, Peter E.
2015-01-01
Introduction: Three-dimensional printing, a technology used for decades in the industrial field, gains a lot of attention in the medical field for its potential benefits. With advancement of desktop printers, this technology is accessible and a lot of research is going on in the medical field. Objective: To evaluate its application in surgical field, which may include but not limited to surgical planning, surgical education, implants, and prosthesis, which are the focus of this review. Methods: Research was conducted by searching PubMed, Web of science, and other reliable sources. We included original articles and excluded articles based on animals, those more than 10 years old, and those not in English. These articles were evaluated, and relevant studies were included in this review. Discussion: Three-dimensional printing shows a potential benefit in surgical application. Printed implants were used in patient in a few cases and show successful results; however, longer follow-up and more trials are needed. Surgical and medical education is believed to be more efficient with this technology than the current practice. Printed surgical instrument and surgical planning are also believed to improve with three-dimensional printing. Conclusion: Three-dimensional printing can be a very powerful tool in the near future, which can aid the medical field that is facing a lot of challenges and obstacles. However, despite the reported results, further research on larger samples and analytical measurements should be conducted to ensure this technology's impact on the practice. PMID:26301002
Three-dimensional implicit lambda methods
NASA Technical Reports Server (NTRS)
Napolitano, M.; Dadone, A.
1983-01-01
This paper derives the three dimensional lambda-formulation equations for a general orthogonal curvilinear coordinate system and provides various block-explicit and block-implicit methods for solving them, numerically. Three model problems, characterized by subsonic, supersonic and transonic flow conditions, are used to assess the reliability and compare the efficiency of the proposed methods.
Co-registered spectral photoacoustic tomography and ultrasonography of breast cancer
NASA Astrophysics Data System (ADS)
Ke, Haixin; Erpelding, Todd N.; Garcia-Uribe, Alejandro; Jacobs, Eileen; Holley, Susan; Monsees, Barbara; Wang, Lihong V.
2014-03-01
Many breast cancer patients receive neoadjuvant treatment to reduce tumor size and enable breast conserving therapy. Most imaging methods used to monitor response to neoadjuvant chemotherapy or hormone therapy depend on overall gross tumor morphology and size measurements, which may not be sensitive or specific, despite tumor response on a cellular level. A more sensitive and specific method of detecting response to therapy might allow earlier adjustments in treatment, and thus result in better outcomes while avoiding unnecessary morbidity. We developed an imaging system that combines spectral photoacoustic tomography and ultrasonography to predict breast neoadjuvant therapeutic response based on blood volume and blood oxygenation contrast. The system consists of a tunable dye laser pumped by a Nd:YAG laser, a commercial ultrasound imaging system (Philips iU22), and a multichannel data acquisition system which displays co-registered photoacoustic and ultrasound images in real time. Early studies demonstrate functional imaging capabilities, such as oxygen saturation and total concentration of hemoglobin, in addition to ultrasonography of tumor morphology. Further study is needed to determine if the co-registered photoacoustic tomography and ultrasonography system may provide an accurate tool to assess treatment efficacy by monitoring tumor response in vivo.
Three-dimensional bio-printing.
Gu, Qi; Hao, Jie; Lu, YangJie; Wang, Liu; Wallace, Gordon G; Zhou, Qi
2015-05-01
Three-dimensional (3D) printing technology has been widely used in various manufacturing operations including automotive, defence and space industries. 3D printing has the advantages of personalization, flexibility and high resolution, and is therefore becoming increasingly visible in the high-tech fields. Three-dimensional bio-printing technology also holds promise for future use in medical applications. At present 3D bio-printing is mainly used for simulating and reconstructing some hard tissues or for preparing drug-delivery systems in the medical area. The fabrication of 3D structures with living cells and bioactive moieties spatially distributed throughout will be realisable. Fabrication of complex tissues and organs is still at the exploratory stage. This review summarize the development of 3D bio-printing and its potential in medical applications, as well as discussing the current challenges faced by 3D bio-printing.
Real time three dimensional sensing system
Gordon, Steven J.
1996-01-01
The invention is a three dimensional sensing system which utilizes two flexibly located cameras for receiving and recording visual information with respect to a sensed object illuminated by a series of light planes. Each pixel of each image is converted to a digital word and the words are grouped into stripes, each stripe comprising contiguous pixels. One pixel of each stripe in one image is selected and an epi-polar line of that point is drawn in the other image. The three dimensional coordinate of each selected point is determined by determining the point on said epi-polar line which also lies on a stripe in the second image and which is closest to a known light plane.
Real time three dimensional sensing system
Gordon, S.J.
1996-12-31
The invention is a three dimensional sensing system which utilizes two flexibly located cameras for receiving and recording visual information with respect to a sensed object illuminated by a series of light planes. Each pixel of each image is converted to a digital word and the words are grouped into stripes, each stripe comprising contiguous pixels. One pixel of each stripe in one image is selected and an epi-polar line of that point is drawn in the other image. The three dimensional coordinate of each selected point is determined by determining the point on said epi-polar line which also lies on a stripe in the second image and which is closest to a known light plane. 7 figs.
Three-dimensional imaging modalities in endodontics
Mao, Teresa
2014-01-01
Recent research in endodontics has highlighted the need for three-dimensional imaging in the clinical arena as well as in research. Three-dimensional imaging using computed tomography (CT) has been used in endodontics over the past decade. Three types of CT scans have been studied in endodontics, namely cone-beam CT, spiral CT, and peripheral quantitative CT. Contemporary endodontics places an emphasis on the use of cone-beam CT for an accurate diagnosis of parameters that cannot be visualized on a two-dimensional image. This review discusses the role of CT in endodontics, pertaining to its importance in the diagnosis of root canal anatomy, detection of peri-radicular lesions, diagnosis of trauma and resorption, presurgical assessment, and evaluation of the treatment outcome. PMID:25279337
Bootstrapping the Three Dimensional Supersymmetric Ising Model.
Bobev, Nikolay; El-Showk, Sheer; Mazáč, Dalimil; Paulos, Miguel F
2015-07-31
We implement the conformal bootstrap program for three dimensional conformal field theories with N=2 supersymmetry and find universal constraints on the spectrum of operator dimensions in these theories. By studying the bounds on the dimension of the first scalar appearing in the operator product expansion of a chiral and an antichiral primary, we find a kink at the expected location of the critical three dimensional N=2 Wess-Zumino model, which can be thought of as a supersymmetric analog of the critical Ising model. Focusing on this kink, we determine, to high accuracy, the low-lying spectrum of operator dimensions of the theory, as well as the stress-tensor two-point function. We find that the latter is in an excellent agreement with an exact computation.
Three-dimensional effects on airfoils
NASA Technical Reports Server (NTRS)
Chevallier, J. P.
1983-01-01
The effects of boundary layer flows along the walls of wind tunnels were studied to validate the transfer of two dimensional calculations to three dimensional transonic flowfield calculations. Results from trials in various wind tunnels were examind to determine the effects of the wall boundary flow on the control surfaces of an airfoil. Models sliding along a groove in the wall of a channel at sub- and transonic speeds were examined, with the finding that with either nonuniformities in the groove, or even if the channel walls are uniform, the lateral boundary layer can cause variations in the central flow region or alter the onset of shock at the transition point. Models for the effects in both turbulence and in the absence of turbulence are formulated, and it is noted that the characteristics of individual wind tunnels must be studied to quantify any existing three dimensional effects.
Three dimensional fabrication at small size scales
Leong, Timothy G.; Zarafshar, Aasiyeh M.; Gracias, David H.
2010-01-01
Despite the fact that we live in a three-dimensional (3D) world and macroscale engineering is 3D, conventional sub-mm scale engineering is inherently two-dimensional (2D). New fabrication and patterning strategies are needed to enable truly three-dimensionally-engineered structures at small size scales. Here, we review strategies that have been developed over the last two decades that seek to enable such millimeter to nanoscale 3D fabrication and patterning. A focus of this review is the strategy of self-assembly, specifically in a biologically inspired, more deterministic form known as self-folding. Self-folding methods can leverage the strengths of lithography to enable the construction of precisely patterned 3D structures and “smart” components. This self-assembling approach is compared with other 3D fabrication paradigms, and its advantages and disadvantages are discussed. PMID:20349446
Three-dimensional imaging modalities in endodontics.
Mao, Teresa; Neelakantan, Prasanna
2014-09-01
Recent research in endodontics has highlighted the need for three-dimensional imaging in the clinical arena as well as in research. Three-dimensional imaging using computed tomography (CT) has been used in endodontics over the past decade. Three types of CT scans have been studied in endodontics, namely cone-beam CT, spiral CT, and peripheral quantitative CT. Contemporary endodontics places an emphasis on the use of cone-beam CT for an accurate diagnosis of parameters that cannot be visualized on a two-dimensional image. This review discusses the role of CT in endodontics, pertaining to its importance in the diagnosis of root canal anatomy, detection of peri-radicular lesions, diagnosis of trauma and resorption, presurgical assessment, and evaluation of the treatment outcome.
Three-dimensional metallic boron nitride.
Zhang, Shunhong; Wang, Qian; Kawazoe, Yoshiyuki; Jena, Puru
2013-12-04
Boron nitride (BN) and carbon are chemical analogues of each other and share similar structures such as one-dimensional nanotubes, two-dimensional nanosheets characterized by sp(2) bonding, and three-dimensional diamond structures characterized by sp(3) bonding. However, unlike carbon which can be metallic in one, two, and three dimensions, BN is an insulator, irrespective of its structure and dimensionality. On the basis of state-of-the-art theoretical calculations, we propose a tetragonal phase of BN which is both dynamically stable and metallic. Analysis of its band structure, density of states, and electron localization function confirms the origin of the metallic behavior to be due to the delocalized B 2p electrons. The metallicity exhibited in the studied three-dimensional BN structures can lead to materials beyond conventional ceramics as well as to materials with potential for applications in electronic devices.
Analysis of three-dimensional transonic compressors
NASA Technical Reports Server (NTRS)
Bourgeade, A.
1984-01-01
A method for computing the three-dimensional transonic flow around the blades of a compressor or of a propeller is given. The method is based on the use of the velocity potential, on the hypothesis that the flow is inviscid, irrotational and isentropic. The equation of the potential is solved in a transformed space such that the surface of the blade is mapped into a plane where the periodicity is implicit. This equation is in a nonconservative form and is solved with the help of a finite difference method using artificial time. A computer code is provided and some sample results are given in order to demonstrate the influence of three-dimensional effects and the blade's rotation.
Three dimensional contact/impact methodology
Kulak, R.F.
1987-01-01
The simulation of three-dimensional interface mechanics between reactor components and structures during static contact or dynamic impact is necessary to realistically evaluate their structural integrity to off-normal loads. In our studies of postulated core energy release events, we have found that significant structure-structure interactions occur in some reactor vessel head closure designs and that fluid-structure interactions occur within the reactor vessel. Other examples in which three-dimensional interface mechanics play an important role are: (1) impact response of shipping casks containing spent fuel, (2) whipping pipe impact on reinforced concrete panels or pipe-to-pipe impact after a pipe break, (3) aircraft crash on secondary containment structures, (4) missiles generated by turbine failures or tornados, and (5) drops of heavy components due to lifting accidents. The above is a partial list of reactor safety problems that require adequate treatment of interface mechanics and are discussed in this paper.
Three Dimensional Particle Tracking in Superfluid Helium
NASA Astrophysics Data System (ADS)
Megson, Peter
2016-11-01
Superfluid helium is a macroscopic quantum state which exhibits exotic physical properties, such as flow without friction and ballistic heat transport. Superfluid flow is irrotational except about line-like topological phase defects with quantized circulation, known as quatized vortices. The presence of these vortices and their dynamics is the dominating factor of turbulence in superfluid flows. One commonly studied regime of superfluid turbulence is thermal counterflow, where a local heat flux drives the formation and growth of a tangle of vortices. This talk will present experimental studies of counterflow turbulence performed using a multi-camera three-dimensional imaging apparatus with micron-sized ice tracer particles as well as fluorescent nanoparticles. In particular, we will discuss the measurement of three-dimensional velocties and their autocorrelations. Additionally, we are developing new techniques for optical studies of bulk superfluid helium, with particular focus on characterizing tracer particles and particle dispersal mechanisms. Funding from NSF DMR-1407472.
Three-dimensional adjustment of trilateration data
NASA Technical Reports Server (NTRS)
Sung, L.-Y.; Jackson, D. D.
1985-01-01
The three-dimensional locations of the monuments in the USGS Hollister trilateration network were adjusted to fit line length observations observed in 1977, using a Bayesian approach, and incorporating prior elevation estimates as data in the adjustment procedure. No significant discrepancies in the measured line lengths were found, but significant elevation adjustments (up to 1.85 m) were needed to fit the length data.
Three-Dimensional Printing in Orthopedic Surgery.
Eltorai, Adam E M; Nguyen, Eric; Daniels, Alan H
2015-11-01
Three-dimensional (3D) printing is emerging as a clinically promising technology for rapid prototyping of surgically implantable products. With this commercially available technology, computed tomography or magnetic resonance images can be used to create graspable objects from 3D reconstructed images. Models can enhance patients' understanding of their pathology and surgeon preoperative planning. Customized implants and casts can be made to match an individual's anatomy. This review outlines 3D printing, its current applications in orthopedics, and promising future directions.
Mineralized Three-Dimensional Bone Constructs
NASA Technical Reports Server (NTRS)
Clarke, Mark S. F. (Inventor); Sundaresan, Alamelu (Inventor); Pellis, Neal R. (Inventor)
2013-01-01
The present disclosure provides ex vivo-derived mineralized three-dimensional bone constructs. The bone constructs are obtained by culturing osteoblasts and osteoclast precursors under randomized gravity vector conditions. Preferably, the randomized gravity vector conditions are obtained using a low shear stress rotating bioreactor, such as a High Aspect Ratio Vessel (HARV) culture system. The bone constructs of the disclosure have utility in physiological studies of bone formation and bone function, in drug discovery, and in orthopedics.
Mineralized three-dimensional bone constructs
NASA Technical Reports Server (NTRS)
Clarke, Mark S. F. (Inventor); Sundaresan, Alamelu (Inventor); Pellis, Neal R. (Inventor)
2011-01-01
The present disclosure provides ex vivo-derived mineralized three-dimensional bone constructs. The bone constructs are obtained by culturing osteoblasts and osteoclast precursors under randomized gravity vector conditions. Preferably, the randomized gravity vector conditions are obtained using a low shear stress rotating bioreactor, such as a High Aspect Ratio Vessel (HARV) culture system. The bone constructs of the disclosure have utility in physiological studies of bone formation and bone function, in drug discovery, and in orthopedics.
Real Imagery as a Three Dimensional Display
1991-12-01
under two categories--stereoscopic and autostereoscopic displays. The difference between these two displays is that autostereoscopic displays do not...require the use of special viewing glasses whereas stereoscopic displays do. In order to place a minimum incumbrance on the viewer, the autostereoscopic ...fooled into believing that the scene is three dimensional. This is accomplished even though the second view that normally comes with an autostereoscopic
Three-dimensional ballistocardiography in weightlessness
NASA Technical Reports Server (NTRS)
Scano, A.
1981-01-01
An experiment is described the aim of which is to record a three dimensional ballistocardiogram under the condition of weightlessness and to compare it with tracings recorded on the same subject on the ground as a means of clarifying the meaning of ballistocardiogram waves in different physiological and perphaps pathological conditions. Another purpose is to investigate cardiovascular and possibly fluid adaptations to weightlessness from data collected almost simultaneously on the same subjects during the other cardiovascular during the other cardiovascular and metabolic experiments.
Three-dimensional simulation of vortex breakdown
NASA Technical Reports Server (NTRS)
Kuruvila, G.; Salas, M. D.
1990-01-01
The integral form of the complete, unsteady, compressible, three-dimensional Navier-Stokes equations in the conservation form, cast in generalized coordinate system, are solved, numerically, to simulate the vortex breakdown phenomenon. The inviscid fluxes are discretized using Roe's upwind-biased flux-difference splitting scheme and the viscous fluxes are discretized using central differencing. Time integration is performed using a backward Euler ADI (alternating direction implicit) scheme. A full approximation multigrid is used to accelerate the convergence to steady state.
Three-dimensional display of document set
Lantrip, David B.; Pennock, Kelly A.; Pottier, Marc C.; Schur, Anne; Thomas, James J.; Wise, James A.
2006-09-26
A method for spatializing text content for enhanced visual browsing and analysis. The invention is applied to large text document corpora such as digital libraries, regulations and procedures, archived reports, and the like. The text content from these sources may e transformed to a spatial representation that preserves informational characteristics from the documents. The three-dimensional representation may then be visually browsed and analyzed in ways that avoid language processing and that reduce the analysts' effort.
Three-dimensional display of document set
Lantrip, David B [Oxnard, CA; Pennock, Kelly A [Richland, WA; Pottier, Marc C [Richland, WA; Schur, Anne [Richland, WA; Thomas, James J [Richland, WA; Wise, James A [Richland, WA
2001-10-02
A method for spatializing text content for enhanced visual browsing and analysis. The invention is applied to large text document corpora such as digital libraries, regulations and procedures, archived reports, and the like. The text content from these sources may be transformed to a spatial representation that preserves informational characteristics from the documents. The three-dimensional representation may then be visually browsed and analyzed in ways that avoid language processing and that reduce the analysts' effort.
Three-dimensional display of document set
Lantrip, David B.; Pennock, Kelly A.; Pottier, Marc C.; Schur, Anne; Thomas, James J.; Wise, James A.; York, Jeremy
2009-06-30
A method for spatializing text content for enhanced visual browsing and analysis. The invention is applied to large text document corpora such as digital libraries, regulations and procedures, archived reports, and the like. The text content from these sources may be transformed to a spatial representation that preserves informational characteristics from the documents. The three-dimensional representation may then be visually browsed and analyzed in ways that avoid language processing and that reduce the analysts' effort.
Three-Dimensional Dispaly Of Document Set
Lantrip, David B.; Pennock, Kelly A.; Pottier, Marc C.; Schur, Anne; Thomas, James J.; Wise, James A.
2003-06-24
A method for spatializing text content for enhanced visual browsing and analysis. The invention is applied to large text document corpora such as digital libraries, regulations and procedures, archived reports, and the like. The text content from these sources may be transformed to a spatial representation that preserves informational characteristics from the documents. The three-dimensional representation may then be visually browsed and analyzed in ways that avoid language processing and that reduce the analysts' effort.
Three Dimensional Inverse Synthetic Aperture Radar Imaging
1995-12-01
to upsample the projection data in order to get sufficient image quality. Working within these memory constraints, three-dimensional images were... metallic film on the windscreen in order to block reflections from the cockpit. Photographs and scale drawings of the model are shown in Figures 11 and...as well as spurious responses in the final image. Theoretically, sufficient resolution should have been available without upsampling the original data
Method and apparatus for three dimensional braiding
NASA Technical Reports Server (NTRS)
Farley, Gary L. (Inventor)
1997-01-01
A machine for three-dimensional braiding of fibers is provided in which carrier members travel on a curved, segmented and movable braiding surface. The carrier members are capable of independent, self-propelled motion along the braiding surface. Carrier member position on the braiding surface is controlled and monitored by computer. Also disclosed is a yarn take-up device capable of maintaining tension in the braiding fiber.
Method and apparatus for three dimensional braiding
NASA Technical Reports Server (NTRS)
Farley, Gary L. (Inventor)
1995-01-01
A machine for three-dimensional braiding of fibers is provided in which carrier members travel on a curved, segmented and movable braiding surface. The carrier members are capable of independent, self-propelled motion along the braiding surface. Carrier member position on the braiding surface is controlled and monitored by computer. Also disclosed is a yarn take-up device capable of maintaining tension in the braiding fiber.
Three-dimensional motor schema based navigation
NASA Technical Reports Server (NTRS)
Arkin, Ronald C.
1989-01-01
Reactive schema-based navigation is possible in space domains by extending the methods developed for ground-based navigation found within the Autonomous Robot Architecture (AuRA). Reformulation of two dimensional motor schemas for three dimensional applications is a straightforward process. The manifold advantages of schema-based control persist, including modular development, amenability to distributed processing, and responsiveness to environmental sensing. Simulation results show the feasibility of this methodology for space docking operations in a cluttered work area.
Three-Dimensional (3D) Distribution
2009-03-11
witnessed by ongoing efforts in both Afghanistan and Iraq , must turn distribution challenges into opportunities by mastering Three-Dimensional (3D...sustainment. 5 Joint Logistics Functions •Supply •Services •Maintenance •Transportation • Health Service Support •General Engineering Joint Personnel...Maintenance •Transportation • Health Service Support •Explosive Ordinance Disposal •Human Resource Support •Legal Support •Religious Support •Financial
Lossless compression for three-dimensional images
NASA Astrophysics Data System (ADS)
Tang, Xiaoli; Pearlman, William A.
2004-01-01
We investigate and compare the performance of several three-dimensional (3D) embedded wavelet algorithms on lossless 3D image compression. The algorithms are Asymmetric Tree Three-Dimensional Set Partitioning In Hierarchical Trees (AT-3DSPIHT), Three-Dimensional Set Partitioned Embedded bloCK (3D-SPECK), Three-Dimensional Context-Based Embedded Zerotrees of Wavelet coefficients (3D-CB-EZW), and JPEG2000 Part II for multi-component images. Two kinds of images are investigated in our study -- 8-bit CT and MR medical images and 16-bit AVIRIS hyperspectral images. First, the performances by using different size of coding units are compared. It shows that increasing the size of coding unit improves the performance somewhat. Second, the performances by using different integer wavelet transforms are compared for AT-3DSPIHT, 3D-SPECK and 3D-CB-EZW. None of the considered filters always performs the best for all data sets and algorithms. At last, we compare the different lossless compression algorithms by applying integer wavelet transform on the entire image volumes. For 8-bit medical image volumes, AT-3DSPIHT performs the best almost all the time, achieving average of 12% decreases in file size compared with JPEG2000 multi-component, the second performer. For 16-bit hyperspectral images, AT-3DSPIHT always performs the best, yielding average 5.8% and 8.9% decreases in file size compared with 3D-SPECK and JPEG2000 multi-component, respectively. Two 2D compression algorithms, JPEG2000 and UNIX zip, are also included for reference, and all 3D algorithms perform much better than 2D algorithms.
Three-dimensional magnetic field annihilation
NASA Astrophysics Data System (ADS)
Jardine, M.; Allen, H. R.; Grundy, R. E.
1993-11-01
We present a family of three-dimensional nonlinear solutions for magnetic field annihilation in a current sheet, including the effects of resistivity and viscosity. The different members of the family are characterized by the imposed vorticity of the flow that brings the field lines together. Since in a three- dimensional flow the vorticity can be increased by the stretching of vortex lines (an effect that is absent in two dimensions), we find some striking differences to our previous two-dimensional analysis. In both the two-dimensional and three-dimensional analyses, above a certain critical imposed vorticity omegacrit, the flow breaks up into cells with current sheet is completely altered. In the two-dimensional analysis, omegacrit is a steeply increasing function of the viscous Reynolds number R, whereas in the three-dimensional case, it quickly asymptotes to only omegacrit = 2v0/L where v0 and L are the characteristic velocity and length scale of the flow, respectively. The width of the current sheet, which depends on the speed at which field lines are carried into it, also responds differently to an increase in R. In two dimensions, the current sheet narrows for all vorticities, but three dimensions, it narrows when the imposed vorticity is negative and widens when it is positive. Also we find that the current density within the current sheet varies as the nature of the flow is changed, rather than being constant as in the the two-dimensional case. Finally, we find that there is a minimum value of the plasma beta betamin below which the plasma pressure is negative. For the nonsheared (neutral current sheet) case, betamin increases rapidly with the magnetic Reynolds number Rm such that this type of annihilation is only possible for a high-beta plasma. For a sheared magnetic field, however, betamin is much lower, making this type of annihilation more relevant to the sonar corona.
Three-Dimensional Shallow Water Acoustics
2015-09-30
1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Three-Dimensional Shallow Water Acoustics Dr. Ying...model to predict acoustic fluctuations and derive sound pressure sensitivity kernels due to 3-D sound speed perturbation in the water column. The...numerical method to be utilized is a tangent linear solution to predict acoustic fluctuations due to 3-D sound speed perturbation in the water column. This
Multiparallel Three-Dimensional Optical Microscopy
NASA Technical Reports Server (NTRS)
Nguyen, Lam K.; Price, Jeffrey H.; Kellner, Albert L.; Bravo-Zanoquera, Miguel
2010-01-01
Multiparallel three-dimensional optical microscopy is a method of forming an approximate three-dimensional image of a microscope sample as a collection of images from different depths through the sample. The imaging apparatus includes a single microscope plus an assembly of beam splitters and mirrors that divide the output of the microscope into multiple channels. An imaging array of photodetectors in each channel is located at a different distance along the optical path from the microscope, corresponding to a focal plane at a different depth within the sample. The optical path leading to each photodetector array also includes lenses to compensate for the variation of magnification with distance so that the images ultimately formed on all the photodetector arrays are of the same magnification. The use of optical components common to multiple channels in a simple geometry makes it possible to obtain high light-transmission efficiency with an optically and mechanically simple assembly. In addition, because images can be read out simultaneously from all the photodetector arrays, the apparatus can support three-dimensional imaging at a high scanning rate.
Three-dimensional printing of the retina
Lorber, Barbara; Hsiao, Wen-Kai; Martin, Keith R.
2016-01-01
Purpose of review Biological three-dimensional printing has received a lot of media attention over recent years with advances made in printing cellular structures, including skin and heart tissue for transplantation. Although limitations exist in creating functioning organs with this method, the hope has been raised that creating a functional retina to cure blindness is within reach. The present review provides an update on the advances made toward this goal. Recent findings It has recently been shown that two types of retinal cells, retinal ganglion cells and glial cells, can be successfully printed using a piezoelectric inkjet printer. Importantly, the cells remained viable and did not change certain phenotypic features as a result of the printing process. In addition, recent advances in the creation of complex and viable three-dimensional cellular structures have been made. Summary Some first promising steps toward the creation of a functional retina have been taken. It now needs to be investigated whether recent findings can be extended to other cells of the retina, including those derived from human tissue, and if a complex and viable retinal structure can be created through three-dimensional printing. PMID:27045545
Reconfigurable, braced, three-dimensional DNA nanostructures.
Goodman, Russell P; Heilemann, Mike; Doose, Sören; Erben, Christoph M; Kapanidis, Achillefs N; Turberfield, Andrew J
2008-02-01
DNA nanotechnology makes use of the exquisite self-recognition of DNA in order to build on a molecular scale. Although static structures may find applications in structural biology and computer science, many applications in nanomedicine and nanorobotics require the additional capacity for controlled three-dimensional movement. DNA architectures can span three dimensions and DNA devices are capable of movement, but active control of well-defined three-dimensional structures has not been achieved. We demonstrate the operation of reconfigurable DNA tetrahedra whose shapes change precisely and reversibly in response to specific molecular signals. Shape changes are confirmed by gel electrophoresis and by bulk and single-molecule Förster resonance energy transfer measurements. DNA tetrahedra are natural building blocks for three-dimensional construction; they may be synthesized rapidly with high yield of a single stereoisomer, and their triangulated architecture conveys structural stability. The introduction of shape-changing structural modules opens new avenues for the manipulation of matter on the nanometre scale.
Three-Dimensional Audio Client Library
NASA Technical Reports Server (NTRS)
Rizzi, Stephen A.
2005-01-01
The Three-Dimensional Audio Client Library (3DAudio library) is a group of software routines written to facilitate development of both stand-alone (audio only) and immersive virtual-reality application programs that utilize three-dimensional audio displays. The library is intended to enable the development of three-dimensional audio client application programs by use of a code base common to multiple audio server computers. The 3DAudio library calls vendor-specific audio client libraries and currently supports the AuSIM Gold-Server and Lake Huron audio servers. 3DAudio library routines contain common functions for (1) initiation and termination of a client/audio server session, (2) configuration-file input, (3) positioning functions, (4) coordinate transformations, (5) audio transport functions, (6) rendering functions, (7) debugging functions, and (8) event-list-sequencing functions. The 3DAudio software is written in the C++ programming language and currently operates under the Linux, IRIX, and Windows operating systems.
Three-dimensional deformation of orthodontic brackets
Melenka, Garrett W; Nobes, David S; Major, Paul W
2013-01-01
Braces are used by orthodontists to correct the misalignment of teeth in the mouth. Archwire rotation is a particular procedure used to correct tooth inclination. Wire rotation can result in deformation to the orthodontic brackets, and an orthodontic torque simulator has been designed to examine this wire–bracket interaction. An optical technique has been employed to measure the deformation due to size and geometric constraints of the orthodontic brackets. Images of orthodontic brackets are collected using a stereo microscope and two charge-coupled device cameras, and deformation of orthodontic brackets is measured using a three-dimensional digital image correlation technique. The three-dimensional deformation of orthodontic brackets will be evaluated. The repeatability of the three-dimensional digital image correlation measurement method was evaluated by performing 30 archwire rotation tests using the same bracket and archwire. Finally, five Damon 3MX and five In-Ovation R self-ligating brackets will be compared using this technique to demonstrate the effect of archwire rotation on bracket design. PMID:23762201
Three-Dimensional Imaging. Chapter 10
NASA Technical Reports Server (NTRS)
Kelso, R. M.; Delo, C.
1999-01-01
This chapter is concerned with three-dimensional imaging of fluid flows. Although relatively young, this field of research has already yielded an enormous range of techniques. These vary widely in cost and complexity, with the cheapest light sheet systems being within the budgets of most laboratories, and the most expensive Magnetic Resonance Imaging systems available to a select few. Taking the view that the most likely systems to be developed are those using light sheets, the authors will relate their knowledge and experience of such systems. Other systems will be described briefly and references provided. Flows are inherently three-dimensional in structure; even those generated around nominally 2-D surface geometry. It is becoming increasingly apparent to scientists and engineers that the three-dimensionalities, both large and small scale, are important in terms of overall flow structure and species, momentum, and energy transport. Furthermore, we are accustomed to seeing the world in three dimensions, so it is natural that we should wish to view, measure and interpret flows in three-dimensions. Unfortunately, 3-D images do not lend themselves to convenient presentation on the printed page, and this task is one of the challenges facing us.
Volumetric Three-Dimensional Display Systems
NASA Astrophysics Data System (ADS)
Blundell, Barry G.; Schwarz, Adam J.
2000-03-01
A comprehensive study of approaches to three-dimensional visualization by volumetric display systems This groundbreaking volume provides an unbiased and in-depth discussion on a broad range of volumetric three-dimensional display systems. It examines the history, development, design, and future of these displays, and considers their potential for application to key areas in which visualization plays a major role. Drawing substantially on material that was previously unpublished or available only in patent form, the authors establish the first comprehensive technical and mathematical formalization of the field, and examine a number of different volumetric architectures. System level design strategies are presented, from which proposals for the next generation of high-definition predictable volumetric systems are developed. To ensure that researchers will benefit from work already completed, they provide: * Descriptions of several recent volumetric display systems prepared from material supplied by the teams that created them * An abstract volumetric display system design paradigm * An historical summary of 90 years of development in volumetric display system technology * An assessment of the strengths and weaknesses of many of the systems proposed to date * A unified presentation of the underlying principles of volumetric display systems * A comprehensive bibliography Beautifully supplemented with 17 color plates that illustrate volumetric images and prototype displays, Volumetric Three-Dimensional Display Systems is an indispensable resource for professionals in imaging systems development, scientific visualization, medical imaging, computer graphics, aerospace, military planning, and CAD/CAE.
Three-dimensional stereo by photometric ratios
Wolff, L.B.; Angelopoulou, E.
1994-11-01
We present a methodology for corresponding a dense set of points on an object surface from photometric values for three-dimensional stereo computation of depth. The methodology utilizes multiple stereo pairs of images, with each stereo pair being taken of the identical scene but under different illumination. With just two stereo pairs of images taken under two different illumination conditions, a stereo pair of ratio images can be produced, one for the ratio of left-hand images and one for the ratio of right-hand images. We demonstrate how the photometric ratios composing these images can be used for accurate correspondence of object points. Object points having the same photometric ratio with respect to two different illumination conditions constitute a well-defined equivalence class of physical constraints defined by local surface orientation relative to illumination conditions. We formally show that for diffuse reflection the photometric ratio is invariant to varying camera characteristics, surface albedo, and viewpoint and that therefore the same photometric ratio in both images of a stereo pair implies the same equivalence class of physical constraints. The correspondence of photometric ratios along epipolar lines in a stereo pair of images under different illumination conditions is a correspondence of equivalent physical constraints, and the determination of depth from stereo can be performed. Whereas illumination planning is required, our photometric-based stereo methodology does not require knowledge of illumination conditions in the actual computation of three-dimensional depth and is applicable to perspective views. This technique extends the stereo determination of three-dimensional depth to smooth featureless surfaces without the use of precisely calibrated lighting. We demonstrate experimental depth maps from a dense set of points on smooth objects of known ground-truth shape, determined to within 1% depth accuracy.
Three-dimensional photoacoustic imaging of breast tissue phantoms
NASA Astrophysics Data System (ADS)
Manohar, Srirang; Kharine, Alexei; Steenbergen, Wiendelt; van Leeuwen, Ton G.
2004-07-01
A laboratory prototype of a time-resolved photoacoustic mammograph, based on a parallel plate geometry is presented. Light is delivered from a Q-switched Nd:YAG laser using fiber-optic bundles which can be mechanically scanned across the surface of a phantom. The ultrasound signals produced by the photoacoustic effect are measured in a transmission mode, using a large-area ultrasound detector matrix. Signals from the matrix are acquired using fast digitizers. Various performance studies of the system are presented. A breast phantom of dimensions (150x120x60)mm was created based on poly(vinyl alcohol) (PVA) gel, which can be imparted with the average optical scattering properties of breast tissue by a simple process of freezing and thawing of an aqueous poly(vinyl alcohol) solution. The acoustic properties are also found to match those of breast tissue. Such a photoacoustic breast phantom was embedded with several tumour-simulating inhomogeneities. These inserts were also based on poly(vinyl alcohol) gels, appropriately dyed at the time of formation, to possess various optical absorption coefficients, between 2 and 7 times that of the background. Using the signals collected from regions-of-interest (ROI) in the volume of the phantom, three-dimensional images were obtained using a modified delay-and-sum beamforming algorithm. The results indicate that photoacoustics, as embodied in this instrument, has a potential for detecting tumours in the breast.
Three-dimensional flow about penguin wings
NASA Astrophysics Data System (ADS)
Noca, Flavio; Sudki, Bassem; Lauria, Michel
2012-11-01
Penguins, contrary to airborne birds, do not need to compensate for gravity. Yet, the kinematics of their wings is highly three-dimensional and seems exceedingly complex for plain swimming. Is such kinematics the result of an evolutionary optimization or is it just a forced adaptation of an airborne flying apparatus to underwater swimming? Some answers will be provided based on flow dynamics around robotic penguin wings. Updates will also be presented on the development of a novel robotic arm intended to simulate penguin swimming and enable novel propulsion devices.
Three-dimensional ultrasonic colloidal crystals
NASA Astrophysics Data System (ADS)
Caleap, Mihai; Drinkwater, Bruce W.
2016-05-01
Colloidal assembly represents a powerful method for the fabrication of functional materials. In this article, we describe how acoustic radiation forces can guide the assembly of colloidal particles into structures that serve as microscopic elements in novel acoustic metadevices or act as phononic crystals. Using a simple three-dimensional orthogonal system, we show that a diversity of colloidal structures with orthorhombic symmetry can be assembled with megahertz-frequency (MHz) standing pressure waves. These structures allow rapid tuning of acoustic properties and provide a new platform for dynamic metamaterial applications.
Electrode With Porous Three-Dimensional Support
Bernard, Patrick; Dauchier, Jean-Michel; Simonneau, Olivier
1999-07-27
Electrode including a paste containing particles of electrochemically active material and a conductive support consisting of a three-dimensional porous material comprising strands delimiting contiguous pores communicating via passages, characterized in that the average width L in .mu.m of said passages is related to the average diameter .O slashed. in .mu.m of said particles by the following equation, in which W and Y are dimensionless coefficients: wherein W=0.16 Y=1.69 X=202.4 .mu.m and Z=80 .mu.m
Three-dimensional simulations of burning thermals
NASA Astrophysics Data System (ADS)
Aspden, Andy; Bell, John; Woosley, Stan
2010-11-01
Flame ignition in type Ia supernovae (SNe Ia) leads to isolated bubbles of burning buoyant fluid. As a bubble rises due to gravity, it becomes deformed by shear instabilities and transitions to a turbulent buoyant vortex ring. Morton, Taylor and Turner (1956) introduced the entrainment assumption, which can be applied to inert thermals. In this study, we use the entrainment assumption, suitably modified to account for burning, to predict the late-time asymptotic behaviour of these turbulent buoyant vortex rings in SNe Ia. The theory is validated against three- dimensional simulations with adaptive mesh refinement at effective resolutions up to 4096^3.
Three-dimensional relativistic electromagnetic subcycle solitons.
Esirkepov, Timur; Nishihara, Katsunobu; Bulanov, Sergei V; Pegoraro, Francesco
2002-12-30
Three-dimensional (3D) relativistic electromagnetic subcycle solitons were observed in 3D particle-in-cell simulations of an intense short-laser-pulse propagation in an underdense plasma. Their structure resembles that of an oscillating electric dipole with a poloidal electric field and a toroidal magnetic field that oscillate in phase with the electron density with frequency below the Langmuir frequency. On the ion time scale, the soliton undergoes a Coulomb explosion of its core, resulting in ion acceleration, and then evolves into a slowly expanding quasineutral cavity.
High resolution three-dimensional doping profiler
Thundat, Thomas G.; Warmack, Robert J.
1999-01-01
A semiconductor doping profiler provides a Schottky contact at one surface and an ohmic contact at the other. While the two contacts are coupled to a power source, thereby establishing an electrical bias in the semiconductor, a localized light source illuminates the semiconductor to induce a photocurrent. The photocurrent changes in accordance with the doping characteristics of the semiconductor in the illuminated region. By changing the voltage of the power source the depth of the depletion layer can be varied to provide a three dimensional view of the local properties of the semiconductor.
NASA Astrophysics Data System (ADS)
Zalev, Jason; Clingman, Bryan; Smith, Remie J.; Herzog, Don; Miller, Tom; Stavros, A. Thomas; Ermilov, Sergey; Conjusteau, André; Tsyboulski, Dmitri; Oraevsky, Alexander A.; Kist, Kenneth; Dornbluth, N. C.; Otto, Pamela
2013-03-01
We report on findings from the clinical feasibility study of the ImagioTM. Breast Imaging System, which acquires two-dimensional opto-acoustic (OA) images co-registered with conventional ultrasound using a specialized duplex hand-held probe. Dual-wavelength opto-acoustic technology is used to generate parametric maps based upon total hemoglobin and its oxygen saturation in breast tissues. This may provide functional diagnostic information pertaining to tumor metabolism and microvasculature, which is complementary to morphological information obtained with conventional gray-scale ultrasound. We present co-registered opto-acoustic and ultrasonic images of malignant and benign tumors from a recent clinical feasibility study. The clinical results illustrate that the technology may have the capability to improve the efficacy of breast tumor diagnosis. In doing so, it may have the potential to reduce biopsies and to characterize cancers that were not seen well with conventional gray-scale ultrasound alone.
Three-dimensional head anthropometric analysis
NASA Astrophysics Data System (ADS)
Enciso, Reyes; Shaw, Alex M.; Neumann, Ulrich; Mah, James
2003-05-01
Currently, two-dimensional photographs are most commonly used to facilitate visualization, assessment and treatment of facial abnormalities in craniofacial care but are subject to errors because of perspective, projection, lack metric and 3-dimensional information. One can find in the literature a variety of methods to generate 3-dimensional facial images such as laser scans, stereo-photogrammetry, infrared imaging and even CT however each of these methods contain inherent limitations and as such no systems are in common clinical use. In this paper we will focus on development of indirect 3-dimensional landmark location and measurement of facial soft-tissue with light-based techniques. In this paper we will statistically evaluate and validate a current three-dimensional image-based face modeling technique using a plaster head model. We will also develop computer graphics tools for indirect anthropometric measurements in a three-dimensional head model (or polygonal mesh) including linear distances currently used in anthropometry. The measurements will be tested against a validated 3-dimensional digitizer (MicroScribe 3DX).
Three-dimensional television: a broadcaster's perspective
NASA Astrophysics Data System (ADS)
Jolly, S. J. E.; Armstrong, M.; Salmon, R. A.
2009-02-01
The recent resurgence of interest in the stereoscopic cinema and the increasing availability to the consumer of stereoscopic televisions and computer displays are leading broadcasters to consider, once again, the feasibility of stereoscopic broadcasting. High Definition Television is now widely deployed, and the R&D departments of broadcasters and consumer electronics manufacturers are starting to plan future enhancements to the experience of television. Improving the perception of depth via stereoscopy is a strong candidate technology. In this paper we will consider the challenges associated with the production, transmission and display of different forms of "three-dimensional" television. We will explore options available to a broadcaster wishing to start a 3D service using the technologies available at the present time, and consider how they could be improved to enable many more television programmes to be recorded and transmitted in a 3D-compatible form, paying particular attention to scenarios such as live broadcasting, where the workflows developed for the stereoscopic cinema are inapplicable. We will also consider the opportunities available for broadcasters to reach audiences with "three-dimensional" content via other media in the near future: for example, distributing content via the existing stereoscopic cinema network, or over the Internet to owners of stereoscopic computer displays.
Two component-three dimensional catalysis
Schwartz, Michael; White, James H.; Sammells, Anthony F.
2002-01-01
This invention relates to catalytic reactor membranes having a gas-impermeable membrane for transport of oxygen anions. The membrane has an oxidation surface and a reduction surface. The membrane is coated on its oxidation surface with an adherent catalyst layer and is optionally coated on its reduction surface with a catalyst that promotes reduction of an oxygen-containing species (e.g., O.sub.2, NO.sub.2, SO.sub.2, etc.) to generate oxygen anions on the membrane. The reactor has an oxidation zone and a reduction zone separated by the membrane. A component of an oxygen containing gas in the reduction zone is reduced at the membrane and a reduced species in a reactant gas in the oxidation zone of the reactor is oxidized. The reactor optionally contains a three-dimensional catalyst in the oxidation zone. The adherent catalyst layer and the three-dimensional catalyst are selected to promote a desired oxidation reaction, particularly a partial oxidation of a hydrocarbon.
Nanowired three-dimensional cardiac patches
NASA Astrophysics Data System (ADS)
Dvir, Tal; Timko, Brian P.; Brigham, Mark D.; Naik, Shreesh R.; Karajanagi, Sandeep S.; Levy, Oren; Jin, Hongwei; Parker, Kevin K.; Langer, Robert; Kohane, Daniel S.
2011-11-01
Engineered cardiac patches for treating damaged heart tissues after a heart attack are normally produced by seeding heart cells within three-dimensional porous biomaterial scaffolds. These biomaterials, which are usually made of either biological polymers such as alginate or synthetic polymers such as poly(lactic acid) (PLA), help cells organize into functioning tissues, but poor conductivity of these materials limits the ability of the patch to contract strongly as a unit. Here, we show that incorporating gold nanowires within alginate scaffolds can bridge the electrically resistant pore walls of alginate and improve electrical communication between adjacent cardiac cells. Tissues grown on these composite matrices were thicker and better aligned than those grown on pristine alginate and when electrically stimulated, the cells in these tissues contracted synchronously. Furthermore, higher levels of the proteins involved in muscle contraction and electrical coupling are detected in the composite matrices. It is expected that the integration of conducting nanowires within three-dimensional scaffolds may improve the therapeutic value of current cardiac patches.
In-lab three-dimensional printing
Partridge, Roland; Conlisk, Noel; Davies, Jamie A.
2012-01-01
The development of the microscope in 1590 by Zacharias Janssenby and Hans Lippershey gave the world a new way of visualizing details of morphogenesis and development. More recent improvements in this technology including confocal microscopy, scanning electron microscopy (SEM) and optical projection tomography (OPT) have enhanced the quality of the resultant image. These technologies also allow a representation to be made of a developing tissue’s three-dimensional (3-D) form. With all these techniques however, the image is delivered on a flat two-dimensional (2-D) screen. 3-D printing represents an exciting potential to reproduce the image not simply on a flat screen, but in a physical, palpable three-dimensional structure. Here we explore the scope that this holds for exploring and interacting with the structure of a developing organ in an entirely novel way. As well as being useful for visualization, 3-D printers are capable of rapidly and cost-effectively producing custom-made structures for use within the laboratory. We here describe the advantages of producing hardware for a tissue culture system using an inexpensive in-lab printer. PMID:22652907
Three dimensional force balance of asymmetric droplets
NASA Astrophysics Data System (ADS)
Kim, Yeseul; Lim, Su Jin; Cho, Kun; Weon, Byung Mook
2016-11-01
An equilibrium contact angle of a droplet is determined by a horizontal force balance among vapor, liquid, and solid, which is known as Young's law. Conventional wetting law is valid only for axis-symmetric droplets, whereas real droplets are often asymmetric. Here we show that three-dimensional geometry must be considered for a force balance for asymmetric droplets. By visualizing asymmetric droplets placed on a free-standing membrane in air with X-ray microscopy, we are able to identify that force balances in one side and in other side control pinning behaviors during evaporation of droplets. We find that X-ray microscopy is powerful for realizing the three-dimensional force balance, which would be essential in interpretation and manipulation of wetting, spreading, and drying dynamics for asymmetric droplets. This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2016R1D1A1B01007133).
Three-dimensional turbopump flowfield analysis
NASA Technical Reports Server (NTRS)
Sharma, O. P.; Belford, K. A.; Ni, R. H.
1992-01-01
A program was conducted to develop a flow prediction method applicable to rocket turbopumps. The complex nature of a flowfield in turbopumps is described and examples of flowfields are discussed to illustrate that physics based models and analytical calculation procedures based on computational fluid dynamics (CFD) are needed to develop reliable design procedures for turbopumps. A CFD code developed at NASA ARC was used as the base code. The turbulence model and boundary conditions in the base code were modified, respectively, to: (1) compute transitional flows and account for extra rates of strain, e.g., rotation; and (2) compute surface heat transfer coefficients and allow computation through multistage turbomachines. Benchmark quality data from two and three-dimensional cascades were used to verify the code. The predictive capabilities of the present CFD code were demonstrated by computing the flow through a radial impeller and a multistage axial flow turbine. Results of the program indicate that the present code operated in a two-dimensional mode is a cost effective alternative to full three-dimensional calculations, and that it permits realistic predictions of unsteady loadings and losses for multistage machines.
Three-dimensional terahertz wave imaging.
Zhang, X-C
2004-02-15
Pulsed terahertz (THz) wave sensing and imaging is a coherent measurement technology. Like radar, based on the phase and amplitude of the THz pulse at each frequency, THz waves provide temporal and spectroscopic information that allows us to develop various three-dimensional (3D) terahertz tomographic imaging modalities. The 3D THz tomographic imaging methods we investigated include THz time-of-flight tomography, THz computed tomography (CT) and THz binary lens tomography. THz time-of-flight uses the THz pulses as a probe beam to temporally mark the target, and then constructs a 3D image of the target using the THz waves scattered by the target. THz CT is based on geometrical optics and inspired from X-ray CT. THz binary lens tomography uses the frequency-dependent focal-length property of binary lenses to obtain tomographic images of an object. Three-dimensional THz imaging has potential in such applications as non-destructive inspection. The interaction between a coherent THz pulse and an object provides rich information about the object under study; therefore, 3D THz imaging can be used to inspect or characterize dielectric and semiconductor objects. For example, 3D THz imaging has been used to detect and identify the defects inside a Space Shuttle insulation tile.
Three-dimensional singular points in aerodynamics
NASA Technical Reports Server (NTRS)
Unal, Aynur
1988-01-01
When three-dimensional separation occurs on a body immersed in a flow governed by the incompressible Navier-Stokes equations, the geometrical surfaces formed by the three vector fields (velocity, vorticity and the skin-friction) and a scalar field (pressure) become interrelated through topological maps containing their respective singular points and extremal points. A mathematically consistent description of these singular points becomes inevitable when we want to study the geometry of the separation. A separated stream surface requires, for example, the existence of a saddle-type singular point on the skin-friction surface. This singular point is actually, in the proper language of mathematics, a saddle of index two. The index is a measure of the dimension of the outset (set leaving the singular point). Hence, when a saddle of index two is specified, a two dimensional surface that becomes separated from the osculating plane of the saddle is implied. The three-dimensional singular point is interpreted mathematically and the most common aerodynamical singular points are discussed through this perspective.
Three dimensional quantum geometry and deformed symmetry
NASA Astrophysics Data System (ADS)
Joung, E.; Mourad, J.; Noui, K.
2009-05-01
We study a three dimensional noncommutative space emerging in the context of three dimensional Euclidean quantum gravity. Our starting point is the assumption that the isometry group is deformed to the Drinfeld double D(SU(2)). We generalize to the deformed case the construction of E3 as the quotient of its isometry group ISU(2) by SU(2). We show that the algebra of functions on E3 becomes the noncommutative algebra of SU(2) distributions, C(SU(2))∗, endowed with the convolution product. This construction gives the action of ISU(2) on the algebra and allows the determination of plane waves and coordinate functions. In particular, we show the following: (i) plane waves have bounded momenta; (ii) to a given momentum are associated several SU(2) elements leading to an effective description of ϕ ɛC(SU(2))∗ in terms of several physical scalar fields on E3; (iii) their product leads to a deformed addition rule of momenta consistent with the bound on the spectrum. We generalize to the noncommutative setting the "local" action for a scalar field. Finally, we obtain, using harmonic analysis, another useful description of the algebra as the direct sum of the algebra of matrices. The algebra of matrices inherits the action of ISU(2): rotations leave the order of the matrices invariant, whereas translations change the order in a way we explicitly determine.
Diagnostic value of three-dimensional transcranial contrast duplex sonography.
Delcker, A; Turowski, B
1997-07-01
This study evaluated intracranial cerebral arteries using a new data acquisition system for transcranial three-dimensional (3D) ultrasonography with and without an echo contrast agent, with confirmation by cerebral angiography. Ten patients, studied with diagnostic cerebral angiography, were examined without knowledge of the angiographic results. Data acquisition through the transtemporal acoustic window was performed using a magnetic sensor system to track the spatial orientation of the ultrasound probe while scanning the volume of interest. A color transcranial duplex system with a power Doppler mode was used, and 3D data sets were acquired before and after the injection of transpulmonary-stable ultrasound contrast medium. Ipsilateral to the transducer, the anterior cerebral artery (ACA) in 90%, middle cerebral artery (MCA) in 60%, all three or more branches of the MCA in 60%, posterior cerebral artery (PCA) in 60%, and posterior communicating artery (PCoA) in 60% were successfully imaged without the echo contrast agent. With the contrast agent, the ACA, MCA, three or more branches of the MCA, PCA, and PCoA were visible in 100%. The anterior communicating artery was visualized in 40% without contrast enhancement and in 90% with contrast enhancement. Contralateral to the transducer, the ACA (60%), MCA (30%), all three or more branches of the MCA (10%), PCA (20%), and PCoA (20%) were successfully imaged without contrast. Contrast enhancement improved the imaging success rate for the ACA (90%), MCA (80%), three or more branches of the MCA (80%), PCA (100%), and PCoA (100%). A transpulmonary-stable ultrasound contrast agent used in combination with 3D transcranial duplex ultrasonography can significantly improve the success rate for transcranial color duplex imaging of intracranial arteries.
Three-dimensional context regulation of metastasis.
Erler, Janine T; Weaver, Valerie M
2009-01-01
Tumor progression ensues within a three-dimensional microenvironment that consists of cellular and non-cellular components. The extracellular matrix (ECM) and hypoxia are two non-cellular components that potently influence metastasis. ECM remodeling and collagen cross-linking stiffen the tissue stroma to promote transformation, tumor growth, motility and invasion, enhance cancer cell survival, enable metastatic dissemination, and facilitate the establishment of tumor cells at distant sites. Matrix degradation can additionally promote malignant progression and metastasis. Tumor hypoxia is functionally linked to altered stromal-epithelial interactions. Hypoxia additionally induces the expression of pro-migratory, survival and invasion genes, and up-regulates expression of ECM components and modifying enzymes, to enhance tumor progression and metastasis. Synergistic interactions between matrix remodeling and tumor hypoxia influence common mechanisms that maximize tumor progression and cooperate to drive metastasis. Thus, clarifying the molecular pathways by which ECM remodeling and tumor hypoxia intersect to promote tumor progression should identify novel therapeutic targets.
Three-dimensional printing physiology laboratory technology
Sulkin, Matthew S.; Widder, Emily; Shao, Connie; Holzem, Katherine M.; Gloschat, Christopher; Gutbrod, Sarah R.
2013-01-01
Since its inception in 19th-century Germany, the physiology laboratory has been a complex and expensive research enterprise involving experts in various fields of science and engineering. Physiology research has been critically dependent on cutting-edge technological support of mechanical, electrical, optical, and more recently computer engineers. Evolution of modern experimental equipment is constrained by lack of direct communication between the physiological community and industry producing this equipment. Fortunately, recent advances in open source technologies, including three-dimensional printing, open source hardware and software, present an exciting opportunity to bring the design and development of research instrumentation to the end user, i.e., life scientists. Here we provide an overview on how to develop customized, cost-effective experimental equipment for physiology laboratories. PMID:24043254
AAOGlimpse: Three-dimensional Data Viewer
NASA Astrophysics Data System (ADS)
Shortridge, Keith
2011-10-01
AAOGlimpse is an experimental display program that uses OpenGL to display FITS data (and even JPEG images) as 3D surfaces that can be rotated and viewed from different angles, all in real-time. It is WCS-compliant and designed to handle three-dimensional data. Each plane in a data cube is surfaced in the same way, and the program allows the user to travel through a cube by 'peeling off' successive planes, or to look into a cube by suppressing the display of data below a given cutoff value. It can blink images and can superimpose images and contour maps from different sources using their world coordinate data. A limited socket interface allows communication with other programs.
Three-dimensional printing physiology laboratory technology.
Sulkin, Matthew S; Widder, Emily; Shao, Connie; Holzem, Katherine M; Gloschat, Christopher; Gutbrod, Sarah R; Efimov, Igor R
2013-12-01
Since its inception in 19th-century Germany, the physiology laboratory has been a complex and expensive research enterprise involving experts in various fields of science and engineering. Physiology research has been critically dependent on cutting-edge technological support of mechanical, electrical, optical, and more recently computer engineers. Evolution of modern experimental equipment is constrained by lack of direct communication between the physiological community and industry producing this equipment. Fortunately, recent advances in open source technologies, including three-dimensional printing, open source hardware and software, present an exciting opportunity to bring the design and development of research instrumentation to the end user, i.e., life scientists. Here we provide an overview on how to develop customized, cost-effective experimental equipment for physiology laboratories.
Versatile three-dimensional cryogenic micropositioning device
NASA Astrophysics Data System (ADS)
Heil, J.; Böhm, A.; Primke, M.; Wyder, P.
1996-01-01
A simple design for a mechanically driven three-dimensional cryogenic micropositioner is presented. The design is based on a parallelogram structure constructed from leaf springs and wires. Actuation is achieved by the elastic deformation of the parallelogram by screws. Positions within a volume of roughly (2 mm)3 are attainable. The precision and reproducibility of positioning are in the μm-range. The deviations from linearity are smaller than 10% for the whole working range and the deviation from orthogonality is smaller than 3°. Calibration measurements performed on a Cu-mesh with a lattice constant of 60 μm are presented. In an experiment investigating the ballistic transport of carriers in the semimetal Bi, two such devices are used. The first one is used as a scanning unit for an optical fiber and the second one is used as micropositioner for a Cu point contact.
Three-dimensional cultured glioma cell lines
NASA Technical Reports Server (NTRS)
Gonda, Steve R. (Inventor); Marley, Garry M. (Inventor)
1991-01-01
Three-dimensional glioma spheroids were produced in vitro with size and histological differentiation previously unattained. The spheroids were grown in liquid media suspension in a Johnson Space Center (JSC) Rotating Wall Bioreactor without using support matrices such as microcarrier beads. Spheroid volumes of greater than 3.5 cu mm and diameters of 2.5 mm were achieved with a viable external layer or rim of proliferating cells, a transitional layer beneath the external layer with histological differentiation, and a degenerative central region with a hypoxic necrotic core. Cell debris was evident in the degenerative central region. The necrotics centers of some of the spheroids had hyaline droplets. Granular bodies were detected predominantly in the necrotic center.
Multiscale modeling of three-dimensional genome
NASA Astrophysics Data System (ADS)
Zhang, Bin; Wolynes, Peter
The genome, the blueprint of life, contains nearly all the information needed to build and maintain an entire organism. A comprehensive understanding of the genome is of paramount interest to human health and will advance progress in many areas, including life sciences, medicine, and biotechnology. The overarching goal of my research is to understand the structure-dynamics-function relationships of the human genome. In this talk, I will be presenting our efforts in moving towards that goal, with a particular emphasis on studying the three-dimensional organization, the structure of the genome with multi-scale approaches. Specifically, I will discuss the reconstruction of genome structures at both interphase and metaphase by making use of data from chromosome conformation capture experiments. Computationally modeling of chromatin fiber at atomistic level from first principles will also be presented as our effort for studying the genome structure from bottom up.
Three-dimensional elastic lidar winds
Buttler, W.T.
1996-07-01
Maximum cross-correlation techniques have been used with satellite data to estimate winds and sea surface velocities for several years. Los Alamos National Laboratory (LANL) is currently using a variation of the basic maximum cross-correlation technique, coupled with a deterministic application of a vector median filter, to measure transverse winds as a function of range and altitude from incoherent elastic backscatter lidar data taken throughout large volumes within the atmospheric boundary layer. Hourly representations of three- dimensional wind fields, derived from elastic lidar data taken during an air-quality study performed in a region of complex terrain near Sunland Park, New Mexico, are presented and compared with results from an Environmental Protection Agency (EPA) approved laser doppler velocimeter. The wind fields showed persistent large scale eddies as well as general terrain following winds in the Rio Grande valley.
Automatic three-dimensional underground mine mapping
Huber, D.F.; Vandapel, N.
2006-01-15
For several years, our research group has been developing methods for automated modeling of three-dimensional environments. In September 2002, we were given the opportunity to demonstrate our mapping capability in an underground coal mine. The opportunity arose as a result of the Quecreek mine accident, in which an inaccurate map caused miners to breach an abandoned, water-filled mine, trapping them for several days. Our field test illustrates the feasibility and potential of high-resolution 3D mapping of an underground coal mine using a cart-mounted 3D laser scanner In this paper we present our experimental setup, the automatic 3D modeling method used, and the results of the field test.
Volumetric techniques: three-dimensional midface modeling
Pierzchała, Ewa; Placek, Waldemar
2014-01-01
Aging is a complex process caused by many factors. The most important factors include exposure to UV radiation, smoking, facial muscle movement, gravity, loss and displacement of fat and bone resorption. As a symptom of aging, face loses elasticity, volume and cheerful look. While changing face proportions, the dominant part of a face is its bottom instead of the mid part. The use of three-dimensional face modelling techniques, particularly the mid-face – tear through and cheeks, restores the skin firmness, volume and healthy look. For this purpose the hyaluronic acid is used, calcium hydroxyapatite, and L-polylactic acid fillers. Volumetric techniques require precision and proper selection of the filling agent to give a sense of satisfaction to both the patient and the doctor. PMID:25610354
Volumetric techniques: three-dimensional midface modeling.
Macierzyńska, Arleta; Pierzchała, Ewa; Placek, Waldemar
2014-12-01
Aging is a complex process caused by many factors. The most important factors include exposure to UV radiation, smoking, facial muscle movement, gravity, loss and displacement of fat and bone resorption. As a symptom of aging, face loses elasticity, volume and cheerful look. While changing face proportions, the dominant part of a face is its bottom instead of the mid part. The use of three-dimensional face modelling techniques, particularly the mid-face - tear through and cheeks, restores the skin firmness, volume and healthy look. For this purpose the hyaluronic acid is used, calcium hydroxyapatite, and L-polylactic acid fillers. Volumetric techniques require precision and proper selection of the filling agent to give a sense of satisfaction to both the patient and the doctor.
Quantum interferometry with three-dimensional geometry.
Spagnolo, Nicolò; Aparo, Lorenzo; Vitelli, Chiara; Crespi, Andrea; Ramponi, Roberta; Osellame, Roberto; Mataloni, Paolo; Sciarrino, Fabio
2012-01-01
Quantum interferometry uses quantum resources to improve phase estimation with respect to classical methods. Here we propose and theoretically investigate a new quantum interferometric scheme based on three-dimensional waveguide devices. These can be implemented by femtosecond laser waveguide writing, recently adopted for quantum applications. In particular, multiarm interferometers include "tritter" and "quarter" as basic elements, corresponding to the generalization of a beam splitter to a 3- and 4-port splitter, respectively. By injecting Fock states in the input ports of such interferometers, fringe patterns characterized by nonclassical visibilities are expected. This enables outperforming the quantum Fisher information obtained with classical fields in phase estimation. We also discuss the possibility of achieving the simultaneous estimation of more than one optical phase. This approach is expected to open new perspectives to quantum enhanced sensing and metrology performed in integrated photonics.
Quantum interferometry with three-dimensional geometry
Spagnolo, Nicolò; Aparo, Lorenzo; Vitelli, Chiara; Crespi, Andrea; Ramponi, Roberta; Osellame, Roberto; Mataloni, Paolo; Sciarrino, Fabio
2012-01-01
Quantum interferometry uses quantum resources to improve phase estimation with respect to classical methods. Here we propose and theoretically investigate a new quantum interferometric scheme based on three-dimensional waveguide devices. These can be implemented by femtosecond laser waveguide writing, recently adopted for quantum applications. In particular, multiarm interferometers include “tritter” and “quarter” as basic elements, corresponding to the generalization of a beam splitter to a 3- and 4-port splitter, respectively. By injecting Fock states in the input ports of such interferometers, fringe patterns characterized by nonclassical visibilities are expected. This enables outperforming the quantum Fisher information obtained with classical fields in phase estimation. We also discuss the possibility of achieving the simultaneous estimation of more than one optical phase. This approach is expected to open new perspectives to quantum enhanced sensing and metrology performed in integrated photonics. PMID:23181189
Scaffolding for Three-Dimensional Embryonic Vasculogenesis
NASA Astrophysics Data System (ADS)
Kraehenbuehl, Thomas P.; Aday, Sezin; Ferreira, Lino S.
Biomaterial scaffolds have great potential to support efficient vascular differentiation of embryonic stem cells. Vascular cell fate-specific biochemical and biophysical cues have been identified and incorporated into three-dimensional (3D) biomaterials to efficiently direct embryonic vasculogenesis. The resulting vascular-like tissue can be used for regenerative medicine applications, further elucidation of biophysical and biochemical cues governing vasculogenesis, and drug discovery. In this chapter, we give an overview on the following: (1) developmental cues for directed differentiation of human embryonic stem cells (hESCs) into vascular cells, (2) 3D vascular differentiation in embryoid bodies (EBs), (3) preparation of 3D scaffolds for the vascular differentiation of hESCs, and (4) the most significant studies combining scaffolding and hESCs for development of vascular-like tissue.
Three-Dimensional Gear Crack Propagation Studies
NASA Technical Reports Server (NTRS)
Lewicki, David G.; Sane, Ashok D.; Drago, Raymond J.; Wawrzynek, Paul A.
1998-01-01
Three-dimensional crack growth simulation was performed on a split-tooth gear design using boundary element modeling and linear elastic fracture mechanics. Initial cracks in the fillet of the teeth produced stress intensity factors of greater magnitude (and thus, greater crack growth rates) than those in the root or groove areas of the teeth. Crack growth simulation was performed on a case study to evaluate crack propagation paths. Tooth fracture was predicted from the crack growth simulation for an initial crack in the tooth fillet region. Tooth loads on the uncracked mesh of the split-tooth design were up to five times greater than those on the cracked mesh if equal deflections of the cracked and uncracked teeth were considered. Predicted crack shapes as well as crack propagation life are presented based on calculated stress intensity factors, mixed-mode crack propagation trajectory theories, and fatigue crack growth theories.
The Three-Dimensional EIT Wave
NASA Technical Reports Server (NTRS)
Thompson, B. J.; Biesecker, D. A.; Gilbert, H. R.; Lawrence, G. R.; Ofman, L.; Wu, S. T.; Warmuth, A.; Fisher, Richard R. (Technical Monitor)
2002-01-01
An EIT wave is an impulsive disturbance which has been observed in the EUV, Soft X-ray and white light corona, with corresponding observations in the chromosphere. The effects of these disturbances can be observed across the entire solar disk of the Sun, and throughout the inner heliosphere as well. However, the picture is not complete; observations alone do not establish a complete understanding of the nature of this three-dimensional phenomenon. A number of associated phenomena have been documented, though in most cases causality has not determined. Additionally, it is unclear which factors govern the impulse's ability to affect regions of the corona and heliosphere. We discuss the various observations and the models which provided links between the associated phenomena.
Three-dimensional hologram display system
NASA Technical Reports Server (NTRS)
Mintz, Frederick (Inventor); Chao, Tien-Hsin (Inventor); Bryant, Nevin (Inventor); Tsou, Peter (Inventor)
2009-01-01
The present invention relates to a three-dimensional (3D) hologram display system. The 3D hologram display system includes a projector device for projecting an image upon a display medium to form a 3D hologram. The 3D hologram is formed such that a viewer can view the holographic image from multiple angles up to 360 degrees. Multiple display media are described, namely a spinning diffusive screen, a circular diffuser screen, and an aerogel. The spinning diffusive screen utilizes spatial light modulators to control the image such that the 3D image is displayed on the rotating screen in a time-multiplexing manner. The circular diffuser screen includes multiple, simultaneously-operated projectors to project the image onto the circular diffuser screen from a plurality of locations, thereby forming the 3D image. The aerogel can use the projection device described as applicable to either the spinning diffusive screen or the circular diffuser screen.
Magneto Transport in Three Dimensional Carbon Nanostructures
NASA Astrophysics Data System (ADS)
Datta, Timir; Wang, Lei; Jaroszynski, Jan; Yin, Ming; Alameri, Dheyaa
Electrical properties of self-assembled three dimensional nanostructures are interesting topic. Here we report temperature dependence of magneto transport in such carbon nanostructures with periodic spherical voids. Specimens with different void diameters in the temperature range from 200 mK to 20 K were studied. Above 2 K, magnetoresistance, MR = [R(B) - R(0)] / R(0), crosses over from quadratic to a linear dependence with the increase of magnetic field [Wang et al., APL 2015; DOI:10.1063/1.4926606]. We observe MR to be non-saturating even up to 18 Tesla. Furthermore, MR demonstrates universality because all experimental data can be collapsed on to a single curve, as a universal function of B/T. Below 2 K, magnetoresistance saturates with increasing field. Quantum Hall like steps are also observed in this low temperature regime. Remarkably, MR of our sample displays orientation independence, an attractive feature for technological applications.
Three dimensional carbon-nanotube polymers.
Zhao, Zhisheng; Xu, Bo; Wang, Li-Min; Zhou, Xiang-Feng; He, Julong; Liu, Zhongyuan; Wang, Hui-Tian; Tian, Yongjun
2011-09-27
Eight fascinating sp(2)- and sp(3)-hybridized carbon allotropes have been uncovered using a newly developed ab initio particle-swarm optimization methodology for crystal structure prediction. These crystalline allotropes can be viewed respectively as three-dimensional (3D) polymers of (4,0), (5,0), (7,0), (8,0), (9,0), (3,3), (4,4), and (6,6) carbon nanotubes, termed 3D-(n, 0) or 3D-(n, n) carbons. The ground-state energy calculations show that the carbons all have lower energies than C(60) fullerene, and some are energetically more stable than the van der Waals packing configurations of their nanotube parents. Owing to their unique configurations, they have distinctive electronic properties, high Young's moduli, high tensile strength, ultrahigh hardness, good ductility, and low density, and may be potentially applied to a variety of needs.
Three-Dimensional Reflectance Traction Microscopy
Jones, Christopher A. R.; Groves, Nicholas Scott; Sun, Bo
2016-01-01
Cells in three-dimensional (3D) environments exhibit very different biochemical and biophysical phenotypes compared to the behavior of cells in two-dimensional (2D) environments. As an important biomechanical measurement, 2D traction force microscopy can not be directly extended into 3D cases. In order to quantitatively characterize the contraction field, we have developed 3D reflectance traction microscopy which combines confocal reflection imaging and partial volume correlation postprocessing. We have measured the deformation field of collagen gel under controlled mechanical stress. We have also characterized the deformation field generated by invasive breast cancer cells of different morphologies in 3D collagen matrix. In contrast to employ dispersed tracing particles or fluorescently-tagged matrix proteins, our methods provide a label-free, computationally effective strategy to study the cell mechanics in native 3D extracellular matrix. PMID:27304456
Three-dimensional image contrast using biospeckle
NASA Astrophysics Data System (ADS)
Godinho, Robson Pierangeli; Braga, Roberto A., Jr.
2010-09-01
The biospeckle laser (BSL) has been applied in many areas of knowledge and a variety of approaches has been presented to address the best results in biological and non-biological samples, in fast or slow activities, or else in defined flow of materials or in random activities. The methodologies accounted in the literature consider the apparatus used in the image assembling and the way the collected data is processed. The image processing steps presents in turn a variety of procedures with first or second order statistics analysis, and as well with different sizes of data collected. One way to access the biospeckle in defined flow, such as in capillary blood flow in alive animals, was the adoption of the image contrast technique which uses only one image from the illuminated sample. That approach presents some problems related to the resolution of the image, which is reduced during the image contrast processing. In order to help the visualization of the low resolution image formed by the contrast technique, this work presents the three-dimensional procedure as a reliable alternative to enhance the final image. The work based on a parallel processing, with the generation of a virtual map of amplitudes, and maintaining the quasi-online characteristic of the contrast technique. Therefore, it was possible to generate in the same display the observed material, the image contrast result and in addiction the three-dimensional image with adjustable options of rotation. The platform also offers to the user the possibility to access the 3D image offline.
Liang, R I; Huang, S E; Chang, F M
1997-08-01
We report here the earliest prenatal diagnosis to date of a case of ectopia cordis using both two-dimensional and three-dimensional ultrasound at 10 weeks of gestation. Both two-dimensional and three-dimensional ultrasound clearly revealed a thoracoabdominal ectopia cordis and an omphalocele. Histopathological examination confirmed the prenatal ultrasonic findings. In addition to an ectopia cordis, a supraumbilical hepato-omphalocele, absence of a pericardium and an anterior diaphragmatic defect were seen, although there was a normal sternum. These pathological findings, suggested that our case was a variant of pentalogy of Cantrell.
... called multiples) To screen for birth defects, like spina bifida or heart defects . Screening means seeing if your ... example, if the ultrasound shows your baby has spina bifida, she may be treated in the womb before ...
MedlinePlus Videos and Cool Tools
... baby's development in the uterus. Ultrasound uses inaudible sound waves to produce a two-dimensional image of the baby while inside the mother's uterus. The sound waves bounce off solid structures in the body ...
Contrast-Enhanced Three Dimensional Ultrasonography supporting HIFU treatment of Small Liver Cancer
NASA Astrophysics Data System (ADS)
Ohto, Masao; Fukuda, Hiroyuki; Ito, Ryu; Shinohara, Yasushi; Sakamoto, Akio; Karasawa, Eii
2009-04-01
HIFU was carried out in the 12 patients with small hepatocellular carcinoma (small HCC) as a extracorporeal ablation therapy, and clinical availability was studied from the results. In carrying out the HIFU therapy, contrast enhanced (CE) three dimensional (3D) ultrasound imaging played an important role to clarify the tumor nature , to monitor the sonication procedure and to assess the tumor ablation and was almost indispensable for the treatment. All the patient had no serious side effects and they are all alive with no local tumor progression for 3 to 14 months after the treatment. Ultrasound supporting HIFU therapy could be usefully available for the treatment of small HCC.
Primary and Secondary Three Dimensional Microbatteries
NASA Astrophysics Data System (ADS)
Cirigliano, Nicolas
Today's MEMS devices are limited more so by the batteries that supply their power than the fabrication methods used to build them. Thick battery electrodes are capable of providing adequate energy, but long and tortuous diffusion pathways lead to low power capabilities. On the other hand, thin film batteries can operate at significant current densities but require large surface areas to supply practical energy. This dilemma can be solved by either developing new high capacity materials or by engineering new battery designs that decouple power and energy. Three dimensional batteries redesign traditional configurations to create nonplanar interfaces between battery components. This can be done by introducing hierarchical structures into the electrode shape. Designs such as these provide a maximum surface area over which chemical reactions can occur. Furthermore, by maintaining small feature sizes, ion diffusion and electronic transport distances can remain minimal. Manipulating these properties ensures fast kinetics that are required for high power situations. Energy density is maximized by layering material in the vertical direction, thus ensuring a minimal footprint area. Three dimensional carbon electrodes are fabricated using basic MEMS techniques. A silicon mold is anisotropically etched to produce channels of a predetermined diameter. The channels are then filled using an infiltration technique with electrode slurry. Once dried, the mold is attached to a current collector and etched using a XeF2 process. Electrodes of varying feature sizes have been fabricated using this method with aspect ratios ranging from 3.5:1 to 7:1. 3D carbon electrodes are shown to obtain capacities over 8 mAh/cm2 at 0.1 mA/cm2, or nearly 700% higher than planar carbon electrodes. When assembled with a planar cathode, the battery cell produced an average discharge capacity of 40 J/cm 2 at a current density of 0.2 mA/cm2. This places the energy density values slightly less than thick
Nanoscale three-dimensional single particle tracking
NASA Astrophysics Data System (ADS)
Dupont, Aurélie; Lamb, Don C.
2011-11-01
Single particle tracking (SPT) in biological systems is a quickly growing field. Many new technologies are being developed providing new tracking capabilities, which also lead to higher demands and expectations for SPT. Following a single biomolecule as it performs its function provides quantitative mechanistic information that cannot be obtained in classical ensemble methods. From the 3D trajectory, information is available over the diffusional behavior of the particle and precise position information can also be used to elucidate interactions of the tracked particle with its surroundings. Thus, three-dimensional (3D) SPT is a very valuable tool for investigating cellular processes. This review presents recent progress in 3D SPT, from image-based techniques toward more sophisticated feedback approaches. We focus mainly on the feedback technique known as orbital tracking. We present here a modified version of the original orbital tracking in which the intensities from two z-planes are simultaneously measured allowing a concomitant wide-field imaging. The system can track single particles with a precision down to 5 nm in the x-y plane and 7 nm in the axial direction. The capabilities of the system are demonstrated using single virus tracing to follow the infection pathway of Prototype Foamy Virus in living cells.Single particle tracking (SPT) in biological systems is a quickly growing field. Many new technologies are being developed providing new tracking capabilities, which also lead to higher demands and expectations for SPT. Following a single biomolecule as it performs its function provides quantitative mechanistic information that cannot be obtained in classical ensemble methods. From the 3D trajectory, information is available over the diffusional behavior of the particle and precise position information can also be used to elucidate interactions of the tracked particle with its surroundings. Thus, three-dimensional (3D) SPT is a very valuable tool for
Three-dimensional ultrasonic Nakagami imaging for tissue characterization
NASA Astrophysics Data System (ADS)
Tsui, Po-Hsiang; Hsu, Cheng-Wei; Ho, Ming-Chih; Chen, Yung-Sheng; Lin, Jen-Jen; Chang, Chien-Cheng; Chu, Chin-Chou
2010-10-01
The two-dimensional (2D) Nakagami image complements the ultrasound B-scan image when attempting to visualize the scatterer properties of tissues. The resolution of the Nakagami image is lower than that of the B-scan image, since the former is produced by processing the raw envelope data using a 2D sliding window with side lengths typically corresponding to three times the pulse length of the incident ultrasound. This paper proposes using three-dimensional (3D) Nakagami imaging for improving the resolution of the obtained Nakagami image and providing more complete information of scatterers for a better tissue characterization. The 3D Nakagami image is based on a voxel array composed of the Nakagami parameters constructed using a 3D sliding cube to process the 3D backscattered raw data. Experiments on phantoms with different scatterer concentrations were carried out to determine the optimal size of the sliding cube for a stable estimation of the Nakagami parameter. Tissue measurements on rat livers without and with fibrosis formation were further used to explore the practical feasibility of 3D Nakagami imaging. The results indicated that the side length of the cube used to construct the 3D Nakagami image must be at least two times the pulse length, which improved the resolution for each Nakagami image frame in the 3D Nakagami image. The results further demonstrated that the 3D Nakagami image is better than the conventional 2D Nakagami image for complementing the B-scan in detecting spatial variations in the scatterer concentration and classifying normal and fibrotic livers. This study suggests that 3D Nakagami imaging has the potential to become a new 3D quantitative imaging approach.
Three-dimensional ultrasonic Nakagami imaging for tissue characterization.
Tsui, Po-Hsiang; Hsu, Cheng-Wei; Ho, Ming-Chih; Chen, Yung-Sheng; Lin, Jen-Jen; Chang, Chien-Cheng; Chu, Chin-Chou
2010-10-07
The two-dimensional (2D) Nakagami image complements the ultrasound B-scan image when attempting to visualize the scatterer properties of tissues. The resolution of the Nakagami image is lower than that of the B-scan image, since the former is produced by processing the raw envelope data using a 2D sliding window with side lengths typically corresponding to three times the pulse length of the incident ultrasound. This paper proposes using three-dimensional (3D) Nakagami imaging for improving the resolution of the obtained Nakagami image and providing more complete information of scatterers for a better tissue characterization. The 3D Nakagami image is based on a voxel array composed of the Nakagami parameters constructed using a 3D sliding cube to process the 3D backscattered raw data. Experiments on phantoms with different scatterer concentrations were carried out to determine the optimal size of the sliding cube for a stable estimation of the Nakagami parameter. Tissue measurements on rat livers without and with fibrosis formation were further used to explore the practical feasibility of 3D Nakagami imaging. The results indicated that the side length of the cube used to construct the 3D Nakagami image must be at least two times the pulse length, which improved the resolution for each Nakagami image frame in the 3D Nakagami image. The results further demonstrated that the 3D Nakagami image is better than the conventional 2D Nakagami image for complementing the B-scan in detecting spatial variations in the scatterer concentration and classifying normal and fibrotic livers. This study suggests that 3D Nakagami imaging has the potential to become a new 3D quantitative imaging approach.
Three-dimensional simulations of fracture dissolution
NASA Astrophysics Data System (ADS)
Starchenko, Vitaliy; Marra, Cameron J.; Ladd, Anthony J. C.
2016-09-01
Numerical studies of fracture dissolution are frequently based on two-dimensional models, where the fracture geometry is represented by an aperture field h(x,y). However, it is known that such models can break down when the spatial variations in aperture are rapid or large in amplitude; for example, in a rough fracture or when instabilities in the dissolution front develop into pronounced channels (or wormholes). Here we report a finite-volume implementation of a three-dimensional reactive transport model using the OpenFOAM® toolkit. Extensions to the OpenFOAM source code have been developed which displace and then relax the mesh in response to variations in the surface concentration; up to 100-fold increases in fracture aperture are possible without remeshing. Our code has simulated field-scale fractures with physical dimensions of about 10 m. We report simulations of smooth fractures, with small, well-controlled perturbations in fracture aperture introduced at the inlet. This allows for systematic convergence studies and for detailed comparisons with results from a two-dimensional model. Initially, the fracture aperture develops similarly in both models, but as local inhomogeneities develop the results start to diverge. We investigate numerically the onset of instabilities in the dissolution of fractures with small random variations in the initial aperture field. Our results show that elliptical cross sections, which are characteristic of karstic conduits, can develop very rapidly, on time scales of 10-20 years in calcite rocks.
Tip selection in three-dimensional dendrites
NASA Astrophysics Data System (ADS)
Foster, M. R.; Tanveer, S.
2004-11-01
Dendrites are well-known to have a fully three-dimensional structure, often with four equally-spaced fins emanating from the steady parabolic tip, the pattern for which has now a good theoretical foundation.(McFadden, Coriell & Sekerka, J. Crys. Growth) 208 (2000) The four fins are of course related to four-fold crystalline anisotropy of quite small magnitude. We follow Tanveer(Tanveer, S. Phys. Rev. A) 40 (1989) in carefully exploring the matching of the inner solution in the neighborhood of the singularity nearest the real line to the small-surface-energy regular perturbation expansion, in order to obtain the (selected) tip radius and the amplitude of the fin. We consider the case for which the anisotropy parameter, α, is much larger than a dimensionless capillary length to the 4/7 power. We confirm what was already found in a slightly different parameter range(Ben Amar & Brener, Phys. Rev. Lett.) 71 (1993)--that the inner equation is essentially that of the two-dimensional case, with azimuthally-dependent parameters. We compare our results with those of Ben Amar & Brener.
Three dimensional characterization and archiving system
Sebastian, R.L.; Clark, R.; Gallman, P.
1996-04-01
The Three Dimensional Characterization and Archiving System (3D-ICAS) is being developed as a remote system to perform rapid in situ analysis of hazardous organics and radionuclide contamination on structural materials. Coleman Research and its subcontractors, Thermedics Detection, Inc. (TD) and the University of Idaho (UI) are in the second phase of a three phase program to develop 3D-ICAS to support Decontamination and Decommissioning (D and D) operations. Accurate physical characterization of surfaces and the radioactive and organic is a critical D and D task. Surface characterization includes identification of potentially dangerous inorganic materials, such as asbestos and transite. Real-time remotely operable characterization instrumentation will significantly advance the analysis capabilities beyond those currently employed. Chemical analysis is a primary area where the characterization process will be improved. The 3D-ICAS system robotically conveys a multisensor probe near the surfaces to be inspected. The sensor position and orientation are monitored and controlled using coherent laser radar (CLR) tracking. The CLR also provides 3D facility maps which establish a 3D world view within which the robotic sensor system can operate.
Three-dimensional context regulation of metastasis
Erler, Janine T.; Weaver, Valerie M.
2009-01-01
Tumor progression ensues within a three-dimensional microenvironment that consists of cellular and non-cellular components. The extracellular matrix (ECM) and hypoxia are two non-cellular components that potently influence metastasis. ECM remodeling and collagen cross-linking stiffen the tissue stroma to promote transformation, tumor growth, motility and invasion, enhance cancer cell survival, enable metastatic dissemination, and facilitate the establishment of tumor cells at distant sites. Matrix degradation can additionally promote malignant progression and metastasis. Tumor hypoxia is functionally linked to altered stromal-epithelial interactions. Hypoxia additionally induces the expression of pro-migratory, survival and invasion genes, and up-regulates expression of ECM components and modifying enzymes, to enhance tumor progression and metastasis. Synergistic interactions between matrix remodeling and tumor hypoxia influence common mechanisms that maximize tumor progression and cooperate to drive metastasis. Thus, clarifying the molecular pathways by which ECM remodeling and tumor hypoxia intersect to promote tumor progression should identify novel therapeutic targets. PMID:18814043
Magnetophotonic response of three-dimensional opals.
Caicedo, José Manuel; Pascu, Oana; López-García, Martín; Canalejas, Víctor; Blanco, Alvaro; López, Cefe; Fontcuberta, Josep; Roig, Anna; Herranz, Gervasi
2011-04-26
Three-dimensional magnetophotonic crystals (3D-MPCs) are being postulated as appropriate platforms to tailor the magneto-optical spectral response of magnetic materials and to incorporate this functionality in a new generation of optical devices. By infiltrating self-assembled inverse opal structures with monodisperse nickel nanoparticles we have fabricated 3D-MPCs that show a sizable enhancement of the magneto-optical signal at frequencies around the stop-band edges of the photonic crystals. We have established a proper methodology to disentangle the intrinsic magneto-optical spectra from the nonmagnetic optical activity of the 3D-MPCs. The results of the optical and magneto-optical characterization are consistent with a homogeneous magnetic infiltration of the opal structure that gives rise to both a red-shift of the optical bandgap and a modification of the magneto-optical spectral response due to photonic bandgap effects. The results of our investigation demonstrate the potential of 3D-MPCs fabricated following the approach outlined here and offer opportunities to adapt the magneto-optical spectral response at optical frequencies by appropriate design of the opal structure or magnetic field strength.
A three-dimensional human walking model
NASA Astrophysics Data System (ADS)
Yang, Q. S.; Qin, J. W.; Law, S. S.
2015-11-01
A three-dimensional human bipedal walking model with compliant legs is presented in this paper. The legs are modeled with time-variant dampers, and the model is able to characterize the gait pattern of an individual using a minimal set of parameters. Feedback control, for both the forward and lateral movements, is implemented to regulate the walking performance of the pedestrian. The model provides an improvement over classic invert pendulum models. Numerical studies were undertaken to investigate the effects of leg stiffness and attack angle. Simulation results show that when walking at a given speed, increasing the leg stiffness with a constant attack angle results in a longer step length, a higher step frequency, a faster walking speed and an increase in both the peak vertical and lateral ground reaction forces. Increasing the attack angle with a constant leg stiffness results in a higher step frequency, a decrease in the step length, an increase in the total energy of the system and a decrease in both the peak vertical and lateral ground reaction forces.
Three-dimensional planning in craniomaxillofacial surgery
Rubio-Palau, Josep; Prieto-Gundin, Alejandra; Cazalla, Asteria Albert; Serrano, Miguel Bejarano; Fructuoso, Gemma Garcia; Ferrandis, Francisco Parri; Baró, Alejandro Rivera
2016-01-01
Introduction: Three-dimensional (3D) planning in oral and maxillofacial surgery has become a standard in the planification of a variety of conditions such as dental implants and orthognathic surgery. By using custom-made cutting and positioning guides, the virtual surgery is exported to the operating room, increasing precision and improving results. Materials and Methods: We present our experience in the treatment of craniofacial deformities with 3D planning. Software to plan the different procedures has been selected for each case, depending on the procedure (Nobel Clinician, Kodak 3DS, Simplant O&O, Dolphin 3D, Timeus, Mimics and 3-Matic). The treatment protocol is exposed step by step from virtual planning, design, and printing of the cutting and positioning guides to patients’ outcomes. Conclusions: 3D planning reduces the surgical time and allows predicting possible difficulties and complications. On the other hand, it increases preoperative planning time and needs a learning curve. The only drawback is the cost of the procedure. At present, the additional preoperative work can be justified because of surgical time reduction and more predictable results. In the future, the cost and time investment will be reduced. 3D planning is here to stay. It is already a fact in craniofacial surgery and the investment is completely justified by the risk reduction and precise results. PMID:28299272
Three-dimensional Diffusive Strip Method
NASA Astrophysics Data System (ADS)
Martinez-Ruiz, Daniel; Meunier, Patrice; Duchemin, Laurent; Villermaux, Emmanuel
2016-11-01
The Diffusive Strip Method (DSM) is a near-exact numerical method developed for mixing computations at large Péclet number in two-dimensions. The method consists in following stretched material lines to compute a-posteriori the resulting scalar field is extended here to three-dimensional flows, following surfaces. We describe its 3D peculiarities, and show how it applies to a simple Taylor-Couette configuration with non-rotating boundary conditions at the top end, bottom and outer cylinder. This flow produces an elaborate, although controlled, steady 3D flow which relies on the Ekman pumping arising from the rotation of the inner cylinder is both studied experimentally, and numerically modeled. A recurrent two-cells structure appears formed by stream tubes shaped as nested tori. A scalar blob in the flow experiences a Lagrangian oscillating dynamics with stretchings and compressions, driving the mixing process, and yielding both rapidly-mixed and nearly pure-diffusive regions. A triangulated-surface method is developed to calculate the blob elongation and scalar concentration PDFs through a single variable computation along the advected blob surface, capturing the rich evolution observed in the experiments.
Lattice theory of three-dimensional cracks
NASA Technical Reports Server (NTRS)
Esterling, D. M.
1976-01-01
The problem of the stability of a three-dimensional crack is analyzed within a lattice-statics approximation. The consequence of introducing a jog into the crack face as well as the effects of various nonlinear-force laws are studied. The phenomenon of lattice trapping (upper and lower bounds on the applied stress for an equilibrium crack of given length) is again obtained. It is possible to obtain some physical insight into which aspects of the force law are critical for crack stability. In particular, the inadequacy of a thermodynamic approach - which relates the critical stress to a surface energy corresponding to the area under the cohesive-force-vs-displacement curve - is demonstrated. Surface energy is a global property of the cohesive-force law. Crack stability is sensitive to much more refined aspects of the cohesive-force law. Crack healing is sensitive to the long-range portion of the cohesive force. Crack expansion is sensitive to the position of the maximum in the cohesive-force relation.
Three-dimensional Printing in the Intestine.
Wengerter, Brian C; Emre, Gulus; Park, Jea Young; Geibel, John
2016-08-01
Intestinal transplantation remains a life-saving option for patients with severe intestinal failure. With the advent of advanced tissue engineering techniques, great strides have been made toward manufacturing replacement tissues and organs, including the intestine, which aim to avoid transplant-related complications. The current paradigm is to seed a biocompatible support material (scaffold) with a desired cell population to generate viable replacement tissue. Although this technique has now been extended by the three-dimensional (3D) printing of geometrically complex scaffolds, the overall approach is hindered by relatively slow turnover and negative effects of residual scaffold material, which affects final clinical outcome. Methods recently developed for scaffold-free 3D bioprinting may overcome such obstacles and should allow for rapid manufacture and deployment of "bioprinted organs." Much work remains before 3D bioprinted tissues can enter clinical use. In this brief review we examine the present state and future perspectives of this nascent technology before full clinical implementation.
Three-dimensional landing zone ladar
NASA Astrophysics Data System (ADS)
Savage, James; Goodrich, Shawn; Burns, H. N.
2016-05-01
Three-Dimensional Landing Zone (3D-LZ) refers to a series of Air Force Research Laboratory (AFRL) programs to develop high-resolution, imaging ladar to address helicopter approach and landing in degraded visual environments with emphasis on brownout; cable warning and obstacle avoidance; and controlled flight into terrain. Initial efforts adapted ladar systems built for munition seekers, and success led to a the 3D-LZ Joint Capability Technology Demonstration (JCTD) , a 27-month program to develop and demonstrate a ladar subsystem that could be housed with the AN/AAQ-29 FLIR turret flown on US Air Force Combat Search and Rescue (CSAR) HH-60G Pave Hawk helicopters. Following the JCTD flight demonstration, further development focused on reducing size, weight, and power while continuing to refine the real-time geo-referencing, dust rejection, obstacle and cable avoidance, and Helicopter Terrain Awareness and Warning (HTAWS) capability demonstrated under the JCTD. This paper summarizes significant ladar technology development milestones to date, individual LADAR technologies within 3D-LZ, and results of the flight testing.
PLOT3D- DRAWING THREE DIMENSIONAL SURFACES
NASA Technical Reports Server (NTRS)
Canright, R. B.
1994-01-01
PLOT3D is a package of programs to draw three-dimensional surfaces of the form z = f(x,y). The function f and the boundary values for x and y are the input to PLOT3D. The surface thus defined may be drawn after arbitrary rotations. However, it is designed to draw only functions in rectangular coordinates expressed explicitly in the above form. It cannot, for example, draw a sphere. Output is by off-line incremental plotter or online microfilm recorder. This package, unlike other packages, will plot any function of the form z = f(x,y) and portrays continuous and bounded functions of two independent variables. With curve fitting; however, it can draw experimental data and pictures which cannot be expressed in the above form. The method used is division into a uniform rectangular grid of the given x and y ranges. The values of the supplied function at the grid points (x, y) are calculated and stored; this defines the surface. The surface is portrayed by connecting successive (y,z) points with straight-line segments for each x value on the grid and, in turn, connecting successive (x,z) points for each fixed y value on the grid. These lines are then projected by parallel projection onto the fixed yz-plane for plotting. This program has been implemented on the IBM 360/67 with on-line CDC microfilm recorder.
Three-dimensional laser velocimeter simultaneity detector
NASA Technical Reports Server (NTRS)
Brown, James L. (Inventor)
1990-01-01
A three-dimensional laser Doppler velocimeter has laser optics for a first channel positioned to create a probe volume in space, and laser optics and for second and third channels, respectively, positioned to create entirely overlapping probe volumes in space. The probe volumes and overlap partially in space. The photodetector is positioned to receive light scattered by a particle present in the probe volume, while photodetectors and are positioned to receive light scattered by a particle present in the probe volume. The photodetector for the first channel is directly connected to provide a first channel analog signal to frequency measuring circuits. The first channel is therefore a primary channel for the system. Photodetectors and are respectively connected through a second channel analog signal attenuator to frequency measuring circuits and through a third channel analog signal attenuator to frequency measuring circuits. The second and third channels are secondary channels, with the second and third channels analog signal attenuators and controlled by the first channel measurement burst signal on line. The second and third channels analog signal attenuators and attenuate the second and third channels analog signals only when the measurement burst signal is false.
Three dimensional, multi-chip module
Bernhardt, A.F.; Petersen, R.W.
1992-12-31
The present invention relates to integrated circuit packaging technology, and particularly to three dimensional packages involving high density stacks of integrated circuits. A plurality of multi-chip modules are stacked and bonded around the perimeter by sold-bump bonds to adjacent modules on, for instance, three sides of the perimeter. The fourth side can be used for coolant distribution, for more interconnect structures, or other features, depending on particular design considerations of the chip set. The multi-chip modules comprise a circuit board, having a planarized interconnect structure formed on a first major surface, and integrated circuit chips bonded to the planarized interconnect surface. Around the periphery of each circuit board, long, narrow ``dummy chips`` are bonded to the finished circuit board to form a perimeter wall. The wall is higher than any of the chips on the circuit board, so that the flat back surface of the board above will only touch the perimeter wall. Module-to-module interconnect is laser-patterned on the sides of the boards and over the perimeter wall in the same way and at the same time that chip to board interconnect may be laser-patterned.
Three dimensional characterization and archiving system
Sebastian, R.L.; Clark, R.; Gallman, P.
1995-10-01
The Three Dimensional Characterization and Archiving System (3D-ICAS) is being developed as a remote system to perform rapid in situ analysis of hazardous organics and radionuclide contamination on structural materials. Coleman Research and its subcontractors, Thermedics Detection, Inc. (TD) and the University of Idaho (UI) are in the second phase of a three phase program to develop 3D-ICAS to support Decontamination and Decommissioning (D&D) operations. Accurate physical characterization of surfaces and the radioactive and organic is a critical D&D task. Surface characterization includes identification of potentially dangerous inorganic materials, such as asbestos and transite. The 3D-ICAS system robotically conveys a multisensor probe near the surface to be inspected. The sensor position and orientation are monitored and controlled by Coherent laser radar (CLR) tracking. The ICAS fills the need for high speed automated organic analysis by means of gas chromatography-mass spectrometry sensors, and also by radionuclide sensors which combines alpha, beta, and gamma counting.
FRET Imaging in Three-dimensional Hydrogels
Taboas, Juan M.
2016-01-01
Imaging of Förster resonance energy transfer (FRET) is a powerful tool for examining cell biology in real-time. Studies utilizing FRET commonly employ two-dimensional (2D) culture, which does not mimic the three-dimensional (3D) cellular microenvironment. A method to perform quenched emission FRET imaging using conventional widefield epifluorescence microscopy of cells within a 3D hydrogel environment is presented. Here an analysis method for ratiometric FRET probes that yields linear ratios over the probe activation range is described. Measurement of intracellular cyclic adenosine monophosphate (cAMP) levels is demonstrated in chondrocytes under forskolin stimulation using a probe for EPAC1 activation (ICUE1) and the ability to detect differences in cAMP signaling dependent on hydrogel material type, herein a photocrosslinking hydrogel (PC-gel, polyethylene glycol dimethacrylate) and a thermoresponsive hydrogel (TR-gel). Compared with 2D FRET methods, this method requires little additional work. Laboratories already utilizing FRET imaging in 2D can easily adopt this method to perform cellular studies in a 3D microenvironment. It can further be applied to high throughput drug screening in engineered 3D microtissues. Additionally, it is compatible with other forms of FRET imaging, such as anisotropy measurement and fluorescence lifetime imaging (FLIM), and with advanced microscopy platforms using confocal, pulsed, or modulated illumination. PMID:27500354
Three-dimensional modelling of Venus photochemistry
NASA Astrophysics Data System (ADS)
Stolzenbach, Aurélien; Lefèvre, Franck; Lebonnois, Sébastien; Määttänen, Anni; Bekki, Slimane
2014-05-01
We have developed a new code of the Venus atmospheric chemistry based on our photochemical model already in use for Mars (e.g., Lefèvre et al., J. Geophys. Res., 2004). For Venus, the code also includes a parameterized treatment of cloud microphysics that computes the composition of sulphuric acid droplets and their number density based on a given droplet size distribution in altitude. We coupled this photochemical-microphysical package to the LMD general circulation model of Venus (Lebonnois et al., J. Geophys. Res., 2010) with a sedimentation module recently added. We will describe preliminary results obtained with this first three-dimensional model of the Venus photochemistry. The space and time distribution of key chemical species as well as the modelled clouds characteristics will be detailed and compared to observations performed from Venus Express and from the Earth (e.g. Knollenberg and Hunten, J. Geophys. Res., 1980 ; Wilquet et al., J. Geophys. Res., 2009 ; Sandor et al., Icarus, 2012).
Three-Dimensional Modelling of Venus Photochemistry
NASA Astrophysics Data System (ADS)
Stolzenbach, A.; Lefèvre, F.; Lebonnois, S.; Maattanen, A. E.; Bekki, S.
2015-12-01
We have developed a new code of the Venus atmospheric chemistry based on our photochemical model already in use for Mars (e.g., Lefèvre et al., J. Geophys. Res., 2004). For Venus, the code also includes a parameterized treatment of cloud microphysics that computes the composition of sulphuric acid droplets and their number density based on a given droplet size distribution in altitude and latitude. We coupled this photochemical-microphysical package to the LMD general circulation model of Venus (Lebonnois et al., J. Geophys. Res., 2010) with a sedimentation module that takes into account the parametrized droplet size distribution. We will describe the results obtained with this first three-dimensional model of the Venus photochemistry. The space and time distribution of key chemical species as well as the modelled clouds characteristics will be detailed and compared to observations performed from Venus Express and from the Earth (e.g. Knollenberg and Hunten, J. Geophys. Res., 1980 ; Wilquet et al., J. Geophys. Res., 2009 ; Sandor et al., Icarus, 2012 ; Mahieux et al., PSS, 2014 ; Marcq et al., 2015, PSS).
Three-dimensional modeling of tsunami waves
Mader, C.L.
1985-01-01
Two- and three-dimensional, time-dependent, nonlinear, incompressible, viscous flow calculations of realistic models of tsunami wave formation and run up have been performed using the Los Alamos-developed SOLA-3D code. The results of the SOLA calculations are compared with shallow-water, long-wave calculations for the same problems using the SWAN code. Tsunami wave formation by a continental slope subsidence has been examined using the two numerical models. The SOLA waves were slower than the SWAN waves and the interaction with the shoreline was more complicated for the SOLA waves. In the SOLA calculation, the first wave was generated by the cavity being filled along the shoreline close to the source of motion. The second wave was generated by the cavity being filled from the deep water end. The two waves interacted along the shoreline resulting in the second wave being the largest wave with a velocity greater than the first wave. The second wave overtook the first wave at later times and greater distances from the source. In the SWAN calculation, the second wave was smaller than the first wave. 6 refs.
Three-dimensional visualization for large models
NASA Astrophysics Data System (ADS)
Roth, Michael W.
2001-09-01
High-resolution (0.3-1 m) digital-elevation data is widely available from commercial sources. Whereas the production of two-dimensional (2D) mapping products from such data is standard practice, the visualization of such three-dimensional (3D) data has been problematic. The basis for this problem is the same as that for the large-model problem in computer graphics-- large amounts of geometry are difficult for current rendering algorithms and hardware. This paper describes a cost-effective solution to this problem that has two parts. First is the employment of the latest in cost-effective 3D chips and video boards that have recently emerged. The second part is the employment of quad-tree data structures for efficient data storage and retrieval during rendering. The result is the capability for real-time display of large (over tens of millions of samples) digital elevation models on modest PC-based systems. This paper shows several demonstrations of this approach using airborne lidar data. The implication of this work is a paradigm shift for geo-spatial information systems--3D data can now be as easy to use as 2D data.
Three Dimensional Characterization of the Mundrabilla Meteorite
NASA Technical Reports Server (NTRS)
Gillies, Donald C.; Engel, H. Peter; Carpenter, P. K.
2003-01-01
The differentiated meteorite, Mundrabilla, exhibits a rare structure of primary kamacite/taenite, and at least 25 volume % of sulfide (troilite and daubreelite). The structure has been investigated in three dimensions using the technique of gamma-ray computed tomography (CT) with a radioactive (60)Co isotope as the source of the flux. Using CT, a 50 kg slab with dimensions 12.6 x 8.2 x approx. 70 cm has been sectioned at 1 mm intervals over 50 cm length, and the three dimensional structure is at present being evaluated. These data revealed, in addition to the metallic and troilite-rich phases, the presence and distribution of graphite-rich cones (up to 5 cm long), and small (1-2 mm), low density particles. The graphite cones are readily visible on the surfaces of many of the sections of Mundrabilla, while the smaller phases have a density (determined from CT) of approximately 2.9 g/cc, and are assumed to be silicate inclusions. CT spatial resolution is not adequate to elucidate the shapes of these particles. One can only state that they show no directionality and are equiaxed.
Two and three dimensional magnetotelluric inversion
Booker, J.
1993-01-01
Electrical conductivity depends on properties such as the presence of ionic fluids in interconnected pores that are difficult to sense with other remote sensing techniques. Thus improved imaging of underground electrical structure has wide practical importance in exploring for groundwater, mineral and geothermal resources, and in assessing the diffusion of fluids in oil fields and waste sites. Because the electromagnetic inverse problem is fundamentally multi-dimensional, most imaging algorithms saturate available computer power long before they can deal with the complete data set. We have developed an algorithm to directly invert large multi-dimensional data sets that is orders of magnitude faster than competing methods. We have proven that a two-dimensional (2D) version of the algorithm is highly effective for real data and have made substantial progress towards a three-dimensional (3D) version. We are proposing to cure identified shortcomings and substantially expand the utility of the existing 2D program, overcome identified difficulties with extending our method to three-dimensions (3D) and embark on an investigation of related EM imaging techniques which may have the potential for even further increasing resolution.
Three-Dimensional Optical Coherence Tomography
NASA Technical Reports Server (NTRS)
Gutin, Mikhail; Wang, Xu-Ming; Gutin, Olga
2009-01-01
Three-dimensional (3D) optical coherence tomography (OCT) is an advanced method of noninvasive infrared imaging of tissues in depth. Heretofore, commercial OCT systems for 3D imaging have been designed principally for external ophthalmological examination. As explained below, such systems have been based on a one-dimensional OCT principle, and in the operation of such a system, 3D imaging is accomplished partly by means of a combination of electronic scanning along the optical (Z) axis and mechanical scanning along the two axes (X and Y) orthogonal to the optical axis. In 3D OCT, 3D imaging involves a form of electronic scanning (without mechanical scanning) along all three axes. Consequently, the need for mechanical adjustment is minimal and the mechanism used to position the OCT probe can be correspondingly more compact. A 3D OCT system also includes a probe of improved design and utilizes advanced signal- processing techniques. Improvements in performance over prior OCT systems include finer resolution, greater speed, and greater depth of field.
Globographic visualisation of three dimensional joint angles.
Baker, Richard
2011-07-07
Three different methods for describing three dimensional joint angles are commonly used in biomechanics. The joint coordinate system and Cardan/Euler angles are conceptually quite different but are known to represent the same underlying mathematics. More recently the globographic method has been suggested as an alternative and this has proved particularly attractive for the shoulder joint. All three methods can be implemented in a number of ways leading to a choice of angle definitions. Very recently Rab has demonstrated that the globographic method is equivalent to one implementation of the joint coordinate system. This paper presents a rigorous analysis of the three different methods and proves their mathematical equivalence. The well known sequence dependence of Cardan/Euler is presented as equivalent to configuration dependence of the joint coordinate system and orientation dependence of globographic angles. The precise definition of different angle sets can be easily visualised using the globographic method using analogues of longitude, latitude and surface bearings with which most users will already be familiar. The method implicitly requires one axis of the moving segment to be identified as its principal axis and this can be extremely useful in helping define the most appropriate angle set to describe the orientation of any particular joint. Using this technique different angle sets are considered to be most appropriate for different joints and examples of this for the hip, knee, ankle, pelvis and axial skeleton are outlined.
Three dimensional imaging with randomly distributed sensors.
DaneshPanah, Mehdi; Javidi, Bahram; Watson, Edward A
2008-04-28
As a promising three dimensional passive imaging modality, Integral Imaging (II) has been investigated widely within the research community. In virtually all of such investigations, there is an implicit assumption that the collection of elemental images lie on a simple geometric surface (e.g. flat, concave, etc), also known as pickup surface. In this paper, we present a generalized framework for 3D II with arbitrary pickup surface geometry and randomly distributed sensor configuration. In particular, we will study the case of Synthetic Aperture Integral Imaging (SAII) with random location of cameras in space, while all cameras have parallel optical axes but different distances from the 3D scene. We assume that the sensors are randomly distributed in 3D volume of pick up space. For 3D reconstruction, a finite number of sensors with known coordinates are randomly selected from within this volume. The mathematical framework for 3D scene reconstruction is developed based on an affine transform representation of imaging under geometrical optics regime. We demonstrate the feasibility of the methods proposed here by experimental results. To the best of our knowledge, this is the first report on 3D imaging using randomly distributed sensors.
Generation of three-dimensional medical thermograms.
Chan, F H; So, A T; Lam, F K
1996-01-01
To visualise non-invasively human organs in their true form and shape has intrigued mankind for centuries. Three-dimensional (3D) imaging is one recent development that has brought us closer to fulfilling the age-old quest of non-invasive visualisation so that diagnoses by doctors can be efficiently enhanced. Nowadays, 3D CT and MRI images have been very popular. Thermography is an important medical imaging technique that displays the temperature distribution on the surface of a human organ and it has been proved to be significant in offering a unique physiological reflection of pathology that may confirm or enhance the anatomic findings of other diagnostic imaging modalities. It is the only imaging modality that can evaluate pain whereas plain radiographs, CT and MRI, etc. can only depict structural anatomic abnormalities that may not always coincide with patients' clinical complaints. It is against this background that 3D thermograms have been developed. A set of comprehensive calibration procedures for the 3-camera system have been designed based on different models for the optical and infrared cameras. The accuracy of the results is high enough to produce 3D thermograms that can be used to correlate with the 3D images from other medical imaging modalities. One important achievement of the system is that the resultant 3D images are absolutely dimensioned and hence, it is particularly favourable for fully autonomous applications with robots. The system can also provide an overall picture of both the structural abnormalities and nervous responses of patients.
Three dimensional characterization and archiving system
Sebastian, R.L.; Clark, R.; Gallman, P.
1995-12-01
The Three Dimensional Characterization and Archiving System (3D-ICAS) is being developed as a remote system to perform rapid in situ analysis of hazardous organics and radionuclide contamination on structural materials. Coleman Research and its subcontractors, Thermedics Detection, Inc. (TD) and the University of Idaho (UI) are in the second phase of a three phase program to develop 3D-ICAS to support Decontamination and Decommissioning (D&D) operations. Accurate physical characterization of surfaces and the radioactive and organic is a critical D&D task. Surface characterization includes identification of potentially dangerous inorganic materials, such as asbestos and transite. Real-time remotely operable characterization instrumentation will significantly advance the analysis capabilities beyond those currently employed. Chemical analysis is a primary area where the characterization process will be improved. Chemical analysis plays a vital role throughout the process of decontamination. Before clean-up operations can begin the site must be characterized with respect to the type and concentration of contaminants, and detailed site mapping must clarify areas of both high and low risk. During remediation activities chemical analysis provides a means to measure progress and to adjust clean-up strategy. Once the clean-up process has been completed the results of chemical analysis will verify that the site is in compliance with federal and local regulations.
Three-dimensional charge coupled device
Conder, Alan D.; Young, Bruce K. F.
1999-01-01
A monolithic three dimensional charged coupled device (3D-CCD) which utilizes the entire bulk of the semiconductor for charge generation, storage, and transfer. The 3D-CCD provides a vast improvement of current CCD architectures that use only the surface of the semiconductor substrate. The 3D-CCD is capable of developing a strong E-field throughout the depth of the semiconductor by using deep (buried) parallel (bulk) electrodes in the substrate material. Using backside illumination, the 3D-CCD architecture enables a single device to image photon energies from the visible, to the ultra-violet and soft x-ray, and out to higher energy x-rays of 30 keV and beyond. The buried or bulk electrodes are electrically connected to the surface electrodes, and an E-field parallel to the surface is established with the pixel in which the bulk electrodes are located. This E-field attracts charge to the bulk electrodes independent of depth and confines it within the pixel in which it is generated. Charge diffusion is greatly reduced because the E-field is strong due to the proximity of the bulk electrodes.
Three-Dimensional Imaging of Viral Infections.
Risco, Cristina; de Castro, Isabel Fernández; Sanz-Sánchez, Laura; Narayan, Kedar; Grandinetti, Giovanna; Subramaniam, Sriram
2014-11-01
Three-dimensional (3D) imaging technologies are beginning to have significant impact in the field of virology, as they are helping us understand how viruses take control of cells. In this article we review several methodologies for 3D imaging of cells and show how these technologies are contributing to the study of viral infections and the characterization of specialized structures formed in virus-infected cells. We include 3D reconstruction by transmission electron microscopy (TEM) using serial sections, electron tomography, and focused ion beam scanning electron microscopy (FIB-SEM). We summarize from these methods selected contributions to our understanding of viral entry, replication, morphogenesis, egress and propagation, and changes in the spatial architecture of virus-infected cells. In combination with live-cell imaging, correlative microscopy, and new techniques for molecular mapping in situ, the availability of these methods for 3D imaging is expected to provide deeper insights into understanding the structural and dynamic aspects of viral infection.
Three-Dimensional Frame Buffers For Interactive Analysis Of Three-Dimensional Data
NASA Astrophysics Data System (ADS)
Hunter, Gregory M.
1986-02-01
Two-dimensional data such as photos, x-rays, various types of satellite images, sonar, radar, seismic plots, etc., in many cases must be analyzed using frame buffers for purposes of medical diagnoses, crop estimates, mineral exploration, and so forth. In many cases the same types of sensors used to gather such samples in two dimensions can gather 3D data for even more effective analysis. Just as 2D arrays of data can be analyzed using frame buffers, three-dimensional data can be analyzed using SOLIDS-BUFFER memories. Image processors deal with samples from two-dimensional arrays and are based on frame buffers. The SOLIDS PROCESSOR system deals with samples from a three-dimensional volume, or solid, and is based on a 3D frame buffer. This paper focuses upon the SOLIDS-BUFFER system as used in the INSIGHT SOLIDS-PROCESSOR system from Phoenix Data Systems.
Antenatal Three-Dimensional Printing of Aberrant Facial Anatomy
VanKoevering, Kyle K.; Morrison, Robert J.; Prabhu, Sanjay P.; Torres, Maria F. Ladino; Mychaliska, George B.; Treadwell, Marjorie C.; Hollister, Scott J.
2015-01-01
Congenital airway obstruction poses a life-threatening challenge to the newborn. We present the first case of three-dimensional (3D) modeling and 3D printing of complex fetal maxillofacial anatomy after prenatal ultrasound indicated potential upper airway obstruction from a midline mass of the maxilla. Using fetal MRI and patient-specific computer-aided modeling, the craniofacial anatomy of the fetus was manufactured using a 3D printer. This model demonstrated the mass to be isolated to the upper lip and maxilla, suggesting the oral airway to be patent. The decision was made to deliver the infant without a planned ex utero intrapartum treatment procedure. The neonate was born with a protuberant cleft lip and palate deformity, without airway obstruction, as predicted by the patient-specific model. The delivery was uneventful, and the child was discharged without need for airway intervention. This case demonstrates that 3D modeling may improve prenatal evaluation of complex patient-specific fetal anatomy and facilitate the multidisciplinary approach to perinatal management of complex airway anomalies. PMID:26438708
Antenatal Three-Dimensional Printing of Aberrant Facial Anatomy.
VanKoevering, Kyle K; Morrison, Robert J; Prabhu, Sanjay P; Torres, Maria F Ladino; Mychaliska, George B; Treadwell, Marjorie C; Hollister, Scott J; Green, Glenn E
2015-11-01
Congenital airway obstruction poses a life-threatening challenge to the newborn. We present the first case of three-dimensional (3D) modeling and 3D printing of complex fetal maxillofacial anatomy after prenatal ultrasound indicated potential upper airway obstruction from a midline mass of the maxilla. Using fetal MRI and patient-specific computer-aided modeling, the craniofacial anatomy of the fetus was manufactured using a 3D printer. This model demonstrated the mass to be isolated to the upper lip and maxilla, suggesting the oral airway to be patent. The decision was made to deliver the infant without a planned ex utero intrapartum treatment procedure. The neonate was born with a protuberant cleft lip and palate deformity, without airway obstruction, as predicted by the patient-specific model. The delivery was uneventful, and the child was discharged without need for airway intervention. This case demonstrates that 3D modeling may improve prenatal evaluation of complex patient-specific fetal anatomy and facilitate the multidisciplinary approach to perinatal management of complex airway anomalies.
Three-dimensional ultrathin planar lenses by acoustic metamaterials.
Li, Yong; Yu, Gaokun; Liang, Bin; Zou, Xinye; Li, Guangyun; Cheng, Su; Cheng, Jianchun
2014-10-30
Acoustic lenses find applications in various areas ranging from ultrasound imaging to nondestructive testing. A compact-size and high-efficient planar acoustic lens is crucial to achieving miniaturization and integration, and should have deep implication for the acoustic field. However its realization remains challenging due to the trade-off between high refractive-index and impedance-mismatch. Here we have designed and experimentally realized the first ultrathin planar acoustic lens capable of steering the convergence of acoustic waves in three-dimensional space. A theoretical approach is developed to analytically describe the proposed metamaterial with hybrid labyrinthine units, which reveals the mechanism of coexistence of high refractive index and well-matched impedance. A hyperbolic gradient-index lens design is fabricated and characterized, which can enhance the acoustic energy by 15 dB at the focal point with very high transmission efficiency. Remarkably, the thickness of the lens is only approximately 1/6 of the operating wavelength. The lens can work within a certain frequency band for which the ratio between the bandwidth and the center frequency reaches 0.74. By tailoring the structure of the metamaterials, one can further reduce the thickness of the lens or even realize other acoustic functionalities, opening new opportunity for manipulation of low-frequency sounds with versatile potential.
Three-dimensional photoacoustic endoscopic imaging of the rabbit esophagus.
Yang, Joon Mo; Favazza, Christopher; Yao, Junjie; Chen, Ruimin; Zhou, Qifa; Shung, K Kirk; Wang, Lihong V
2015-01-01
We report photoacoustic and ultrasonic endoscopic images of two intact rabbit esophagi. To investigate the esophageal lumen structure and microvasculature, we performed in vivo and ex vivo imaging studies using a 3.8-mm diameter photoacoustic endoscope and correlated the images with histology. Several interesting anatomic structures were newly found in both the in vivo and ex vivo images, which demonstrates the potential clinical utility of this endoscopic imaging modality. In the ex vivo imaging experiment, we acquired high-resolution motion-artifact-free three-dimensional photoacoustic images of the vasculatures distributed in the walls of the esophagi and extending to the neighboring mediastinal regions. Blood vessels with apparent diameters as small as 190 μm were resolved. Moreover, by taking advantage of the dual-mode high-resolution photoacoustic and ultrasound endoscopy, we could better identify and characterize the anatomic structures of the esophageal lumen, such as the mucosal and submucosal layers in the esophageal wall, and an esophageal branch of the thoracic aorta. In this paper, we present the first photoacoustic images showing the vasculature of a vertebrate esophagus and discuss the potential clinical applications and future development of photoacoustic endoscopy.
Applicability of three-dimensional imaging techniques in fetal medicine*
Werner Júnior, Heron; dos Santos, Jorge Lopes; Belmonte, Simone; Ribeiro, Gerson; Daltro, Pedro; Gasparetto, Emerson Leandro; Marchiori, Edson
2016-01-01
Objective To generate physical models of fetuses from images obtained with three-dimensional ultrasound (3D-US), magnetic resonance imaging (MRI), and, occasionally, computed tomography (CT), in order to guide additive manufacturing technology. Materials and Methods We used 3D-US images of 31 pregnant women, including 5 who were carrying twins. If abnormalities were detected by 3D-US, both MRI and in some cases CT scans were then immediately performed. The images were then exported to a workstation in DICOM format. A single observer performed slice-by-slice manual segmentation using a digital high resolution screen. Virtual 3D models were obtained from software that converts medical images into numerical models. Those models were then generated in physical form through the use of additive manufacturing techniques. Results Physical models based upon 3D-US, MRI, and CT images were successfully generated. The postnatal appearance of either the aborted fetus or the neonate closely resembled the physical models, particularly in cases of malformations. Conclusion The combined use of 3D-US, MRI, and CT could help improve our understanding of fetal anatomy. These three screening modalities can be used for educational purposes and as tools to enable parents to visualize their unborn baby. The images can be segmented and then applied, separately or jointly, in order to construct virtual and physical 3D models. PMID:27818540
Three-dimensional volume analysis of vasculature in engineered tissues
NASA Astrophysics Data System (ADS)
YousefHussien, Mohammed; Garvin, Kelley; Dalecki, Diane; Saber, Eli; Helguera, María.
2013-01-01
Three-dimensional textural and volumetric image analysis holds great potential in understanding the image data produced by multi-photon microscopy. In this paper, an algorithm that quantitatively analyzes the texture and the morphology of vasculature in engineered tissues is proposed. The investigated 3D artificial tissues consist of Human Umbilical Vein Endothelial Cells (HUVEC) embedded in collagen exposed to two regimes of ultrasound standing wave fields under different pressure conditions. Textural features were evaluated using the normalized Gray-Scale Cooccurrence Matrix (GLCM) combined with Gray-Level Run Length Matrix (GLRLM) analysis. To minimize error resulting from any possible volume rotation and to provide a comprehensive textural analysis, an averaged version of nine GLCM and GLRLM orientations is used. To evaluate volumetric features, an automatic threshold using the gray level mean value is utilized. Results show that our analysis is able to differentiate among the exposed samples, due to morphological changes induced by the standing wave fields. Furthermore, we demonstrate that providing more textural parameters than what is currently being reported in the literature, enhances the quantitative understanding of the heterogeneity of artificial tissues.
Identifying ultrasonic scattering sites from three-dimensional impedance maps
NASA Astrophysics Data System (ADS)
Mamou, Jonathan; Oelze, Michael L.; O'Brien, William D.; Zachary, James F.
2005-01-01
Ultrasonic backscattered signals contain frequency-dependent information that is usually discarded to produce conventional B-mode images. It is hypothesized that parametrization of the quantitative ultrasound frequency-dependent information (i.e., estimating scatterer size and acoustic concentration) may be related to discrete scattering anatomic structures in tissues. Thus, an estimation technique is proposed to extract scatterer size and acoustic concentration from the power spectrum derived from a three-dimensional impedance map (3DZM) of a tissue volume. The 3DZM can be viewed as a computational phantom and is produced from a 3D histologic data set. The 3D histologic data set is constructed from tissue sections that have been appropriately stained to highlight specific tissue features. These tissue features are assigned acoustic impedance values to yield a 3DZM. From the power spectrum, scatterer size and acoustic concentration estimates were obtained by optimization. The 3DZM technique was validated by simulations that showed relative errors of less than 3% for all estimated parameters. Estimates using the 3DZM technique were obtained and compared against published ultrasonically derived estimates for two mammary tumors, a rat fibroadenoma and a 4T1 mouse mammary carcinoma. For both tumors, the relative difference between ultrasonic and 3DZM estimates was less than 10% for the average scatterer size. .
Geroux, Christopher M.; Deupree, Robert G.
2015-02-10
Three-dimensional hydrodynamic simulations of full amplitude RR Lyrae stars have been computed for several models across the instability strip. The three-dimensional nature of the calculations allows convection to be treated without reference to a phenomenological approach such as the local mixing length theory. Specifically, the time-dependent interaction of large-scale eddies and radial pulsation is controlled by conservation laws, while the effects of smaller convective eddies are simulated by an eddy viscosity model. The light amplitudes for these calculations are quite similar to those of our previous two-dimensional calculations in the middle of the instability strip, but somewhat lower near the red edge, the fundamental blue edge, and for the one first overtone model we computed. The time-dependent interaction between the radial pulsation and the convective energy transport is essentially the same in three dimensions as it is in two dimensions. There are some differences between the light curves of the two- and three-dimensional simulations, particularly during decreasing light. Reasons for the differences, both numerical and physical, are explored.
Three-dimensional ring current decay model
NASA Technical Reports Server (NTRS)
Fok, Mei-Ching; Moore, Thomas E.; Kozyra, Janet U.; Ho, George C.; Hamilton, Douglas C.
1995-01-01
This work is an extension of a previous ring current decay model. In the previous work, a two-dimensional kinetic model was constructed to study the temporal variations of the equatorially mirroring ring current ions, considering charge exchange and Coulomb drag losses along drift paths in a magnetic dipole field. In this work, particles with arbitrary pitch angle are considered. By bounce averaging the kinetic equation of the phase space density, information along magnetic field lines can be inferred from the equator. The three-dimensional model is used to simulate the recovery phase of a model great magnetic storm, similar to that which occurred in early February 1986. The initial distribution of ring current ions (at the minimum Dst) is extrapolated to all local times from AMPTE/CCE spacecraft observations on the dawnside and duskside of the inner magnetosphere spanning the L value range L = 2.25 to 6.75. Observations by AMPTE/CCE of ring current distributions over subsequent orbits during the storm recovery phase are compared to model outputs. In general, the calculated ion fluxes are consistent with observations, except for H(+) fluxes at tens of keV, which are always overestimated. A newly invented visualization idea, designated as a chromogram, is used to display the spatial and energy dependence of the ring current ion differential flux. Important features of storm time ring current, such as day-night asymmetry during injection and drift hole on the dayside at low energies (less than 10 keV), are manifested in the chromogram representation. The pitch angle distribution is well fit by the function, J(sub o)(1 + Ay(sup n)), where y is sine of the equatorial pitch angle. The evolution of the index n is a combined effect of charge exchange loss and particle drift. At low energies (less than 30 keV), both drift dispersion and charge exchange are important in determining n.
Remote Dynamic Three-Dimensional Scene Reconstruction
Yang, You; Liu, Qiong; Ji, Rongrong; Gao, Yue
2013-01-01
Remote dynamic three-dimensional (3D) scene reconstruction renders the motion structure of a 3D scene remotely by means of both the color video and the corresponding depth maps. It has shown a great potential for telepresence applications like remote monitoring and remote medical imaging. Under this circumstance, video-rate and high resolution are two crucial characteristics for building a good depth map, which however mutually contradict during the depth sensor capturing. Therefore, recent works prefer to only transmit the high-resolution color video to the terminal side, and subsequently the scene depth is reconstructed by estimating the motion vectors from the video, typically using the propagation based methods towards a video-rate depth reconstruction. However, in most of the remote transmission systems, only the compressed color video stream is available. As a result, color video restored from the streams has quality losses, and thus the extracted motion vectors are inaccurate for depth reconstruction. In this paper, we propose a precise and robust scheme for dynamic 3D scene reconstruction by using the compressed color video stream and their inaccurate motion vectors. Our method rectifies the inaccurate motion vectors by analyzing and compensating their quality losses, motion vector absence in spatial prediction, and dislocation in near-boundary region. This rectification ensures the depth maps can be compensated in both video-rate and high resolution at the terminal side towards reducing the system consumption on both the compression and transmission. Our experiments validate that the proposed scheme is robust for depth map and dynamic scene reconstruction on long propagation distance, even with high compression ratio, outperforming the benchmark approaches with at least 3.3950 dB quality gains for remote applications. PMID:23667417
Three-dimensional Spontaneous Magnetic Reconnection
NASA Astrophysics Data System (ADS)
Beresnyak, Andrey
2017-01-01
Magnetic reconnection is best known from observations of the Sun where it causes solar flares. Observations estimate the reconnection rate as a small, but non-negligible fraction of the Alfvén speed, so-called fast reconnection. Until recently, the prevailing pictures of reconnection were either of resistivity or plasma microscopic effects, which was contradictory to the observed rates. Alternative pictures were either of reconnection due to the stochasticity of magnetic field lines in turbulence or the tearing instability of the thin current sheet. In this paper we simulate long-term three-dimensional nonlinear evolution of a thin, planar current sheet subject to a fast oblique tearing instability using direct numerical simulations of resistive-viscous magnetohydrodynamics. The late-time evolution resembles generic turbulence with a ‑5/3 power spectrum and scale-dependent anisotropy, so we conclude that the tearing-driven reconnection becomes turbulent reconnection. The turbulence is local in scale, so microscopic diffusivity should not affect large-scale quantities. This is confirmed by convergence of the reconnection rate toward ∼ 0.015{v}{{A}} with increasing Lundquist number. In this spontaneous reconnection, with mean field and without driving, the dissipation rate per unit area also converges to ∼ 0.006ρ {v}{{A}}3, and the dimensionless constants 0.015 and 0.006 are governed only by self-driven nonlinear dynamics of the sheared magnetic field. Remarkably, this also means that a thin current sheet has a universal fluid resistance depending only on its length to width ratio and to {v}{{A}}/c.
Three-dimensional topological insulator based nanospaser
NASA Astrophysics Data System (ADS)
Paudel, Hari P.; Apalkov, Vadym; Stockman, Mark I.
2016-04-01
After the discovery of the spaser (surface plasmon amplification by stimulated emission of radiation), first proposed by Bergman and Stockman in 2003, it has become possible to deliver optical energy beyond the diffraction limit and generate an intense source of an optical field. The spaser is a nanoplasmonic counterpart of a laser. One of the major advantages of the spaser is its size: A spaser is a truly nanoscopic device whose size can be made smaller than the skin depth of a material to a size as small as the nonlocality radius (˜1 nm). Recently, an electrically pumped graphene based nanospaser has been proposed that operates in the midinfrared region and utilizes a nanopatch of graphene as a source of plasmons and a quantum-well cascade as its gain medium. Here we propose an optically pumped nanospaser based on three-dimensional topological insulator (3D TI) materials, such as Bi2Se3 , that operates at an energy close to the bulk band-gap energy ˜0.3 eV and uses the surface as a source for plasmons and its bulk as a gain medium. Population inversion is obtained in the bulk and the radiative energy of the exciton recombination is transferred to the surface plasmons of the same material to stimulate spasing action. This is truly a nanoscale spaser as it utilizes the same material for dual purposes. We show theoretically the possibility of achieving spasing with a 3D TI. As the spaser operates in the midinfrared spectral region, it can be a useful device for a number of applications, such as nanoscopy, nanolithography, nanospectroscopy, and semiclassical information processing.
[Three-dimensional reconstruction of heart valves].
Flachskampf, F A; Kühl, H; Franke, A; Frielingsdorf, J; Klues, H; Krebs, W; Hanrath, P
1995-08-01
The reconstruction of three-dimensional data sets from two-dimensional echocardiographic images offers several fundamental advantages: 1. more complete data than present in the few standard 2D-view; 2. off-line generation of any desired plane, cut, or perspective after the data set has been acquired; 3. access to quantitative parameters like surface areas (e.g., of valve leaflets or portions of leaflets), volumes, and others, without geometric assumptions. The mitral valve has been the focus of several studies using various techniques of reconstruction of transthoracic or transesophageal images. These studies have shown the mitral annulus to be a non-planar, "saddle-shaped" structure, with an average distance of highest to lowest points of 14 mm in normals. This recognition of mitral annular non-planarity has led to a more stringent echocardiographic definition of mitral valve prolapse. Further studies have shown systolic shrinkage of mitral annular area by about 30% and systolic apico-basal translation of the annulus by approximately 1 cm in normals. In patients with dilated cardiomyopathy, the annulus is flattened, and both cyclic change in annular area and apico-basal translation are significantly reduced. 3D-studies of the left ventricular outflow tract in hypertrophic obstructive cardiomyopathy allow measurement of outflow tract and leaflet surface areas and dynamic spatial visualization of systolic anterior motion of the anterior mitral leaflet. Automated techniques to reconstruct the full grey value data set from a high number of parallel or rotational transesophageal planes allow impressive visualization of normal and diseased mitral and aortic valves or valve prostheses, with special emphasis on generating "surgical" views and perspectives, which cannot be obtained by conventional tomographic imaging.(ABSTRACT TRUNCATED AT 250 WORDS)
Three-dimensional carbon nanotube based photovoltaics
NASA Astrophysics Data System (ADS)
Flicker, Jack
2011-12-01
Photovoltaic (PV) cells with a three dimensional (3D) morphology are an exciting new research thrust with promise to create cheaper, more efficient solar cells. This work introduces a new type of 3D PV device based on carbon nanotube (CNT) arrays. These arrays are paired with the thin film heterojunction, CdTe/CdS, to form a complete 3D carbon nanotube PV device (3DCNTPV). Marriage of a complicated 3D structure with production methods traditionally used for planar CdTe solar cell is challenging. This work examines the problems associated with processing these types of cells and systematically alters production methods of the semiconductor layers and electrodes to increase the short circuit current (Isc), eliminate parasitic shunts, and increase the open circuit voltage (Voc). The main benefit of 3D solar cell is the ability to utilize multiple photon interactions with the solar cell surface. The three dimensionality allows photons to interact multiple times with the photoactive material, which increases the absorption and the overall power output over what is possible with a two dimensional (2D) morphology. To quantify the increased power output arising from these multiple photon interactions, a new absorption efficiency term, eta3D, is introduced. The theoretical basis behind this new term and how it relates to the absorption efficiency of a planar cell, eta 2D, is derived. A unique model for the average number of multiple photon impingements, Gamma, is proposed based on three categories of 3D morphology: an infinite trench, an enclosed box, and an array of towers. The derivation of eta3D and Gamma for these 3D PV devices gives a complete picture of the enhanced power output over 2D cells based on CNT array height, pitch, radius, and shape. This theory is validated by monte carlo simulations and experiment. This new type of 3D PV devices has been shown to work experimentally. The first 3DCNTPV cells created posses Isc values of 0.085 to 17.872mA/cm2 and Voc values
Ultrasound and photoacoustic imaging to monitor vascular growth in tissue engineered constructs
NASA Astrophysics Data System (ADS)
Nam, Seung Yun; Mallidi, Srivalleesha; Zhang, Ge; Suggs, Laura J.; Emelianov, Stanislav
2009-02-01
Quantitative and qualitative monitoring of neovascular growth is required in many vascular tissue engineering applications. For example, the contribution of progenitor cells in growing microvasculature has been demonstrated; however, the process of vascularization from progenitor cells is not well understood. Therefore, there is a need for an imaging technique that is consistent, easy to use, and can quantitatively assess the dynamics of vascular growth or regression in a three-dimensional environment. In this study, we evaluate the ability of combined ultrasound and photoacoustic imaging to assess the dynamics of vascular growth. The experiments were performed using hydrogels that spontaneously promote tube formation from implanted mesenchymal stem cells (MSCs). Specifically, PEGylated fibrin gels, supporting the development of capillary growth were implanted in a Lewis rat. After one week, the rat was euthanized and the gel implants were excised and positioned in water cuvettes for imaging. Simultaneous ultrasound and photoacoustic images were obtained using single-element, focused ultrasound transducers interfaced with a nanosecond pulsed laser source. To image samples, ultrasound transducers operating at either 25 MHz or 48 MHz and interfaced with laser sources operating at either 532 nm or within 680-800 nm wavelengths were used. The 3-D ultrasound and photoacoustic images were acquired by mechanically scanning the transducer over the region of interest and capturing spatially co-registered and temporally consecutive photoacoustic transients and ultrasound pulse-echo signals. The ultrasound and photoacoustic images agree well with the overall anatomy and vascular structure in the gel samples. The results suggest that the photoacoustic and ultrasound imaging could be used to sequentially monitor the growth of neovasculature in-vivo.
Numerical investigations in three-dimensional internal flows
NASA Technical Reports Server (NTRS)
Rose, William C.
1991-01-01
The present study is a preliminary investigation into the behavior of the flow within a 28 degree total geometric turning angle hypothetical Mach 10 inlet as calculated with the full three-dimensional Navier-Stokes equations. Comparison between the two-dimensional and three-dimensional solutions have been made. The overall compression is not significantly different between the two-dimensional and center plane three dimensional solutions. Approximately one-half to two-thirds of the inlet flow at the exit of the inlet behave nominally two-dimensionally. On the other hand, flow field non-uniformities in the three-dimensional solution indicate the potential significance of the sidewall boundary layer flows ingested into the inlet. The tailoring of the geometry at the inlet shoulder and on the cowl obtained in the two-dimensional parametric design study have also proved to be effective at controlling the boundary layer behavior in the three-dimensional code. The three-dimensional inlet solution remained started indicating that the two-dimensional design had a sufficient margin to allow for three-dimensional flow field effects. Although confidence is being gained in the use of SCRAM3D (three-dimensional full Navier-Stokes code) as applied to similar flow fields, the actual effects of the three-dimensional flow fields associated with sidewalls and wind tunnel installations can require verification with ground-based experiments.
Three-Dimensional Gear Crack Propagation Studied
NASA Technical Reports Server (NTRS)
Lewicki, David G.
1999-01-01
Gears used in current helicopters and turboprops are designed for light weight, high margins of safety, and high reliability. However, unexpected gear failures may occur even with adequate tooth design. To design an extremely safe system, the designer must ask and address the question, "What happens when a failure occurs?" With gear-tooth bending fatigue, tooth or rim fractures may occur. A crack that propagates through a rim will be catastrophic, leading to disengagement of the rotor or propeller, loss of an aircraft, and possible fatalities. This failure mode should be avoided. A crack that propagates through a tooth may or may not be catastrophic, depending on the design and operating conditions. Also, early warning of this failure mode may be possible because of advances in modern diagnostic systems. One concept proposed to address bending fatigue fracture from a safety aspect is a splittooth gear design. The prime objective of this design would be to control crack propagation in a desired direction such that at least half of the tooth would remain operational should a bending failure occur. A study at the NASA Lewis Research Center analytically validated the crack-propagation failsafe characteristics of a split-tooth gear. It used a specially developed three-dimensional crack analysis program that was based on boundary element modeling and principles of linear elastic fracture mechanics. Crack shapes as well as the crack-propagation life were predicted on the basis of the calculated stress intensity factors, mixed-mode crack-propagation trajectory theories, and fatigue crack-growth theories. The preceding figures show the effect of the location of initial cracks on crack propagation. Initial cracks in the fillet of the teeth produced stress intensity factors of greater magnitude (and thus, greater crack growth rates) than those in the root or groove areas of the teeth. Crack growth was simulated in a case study to evaluate crack-propagation paths. Tooth
Advanced Three-Dimensional Display System
NASA Technical Reports Server (NTRS)
Geng, Jason
2005-01-01
A desktop-scale, computer-controlled display system, initially developed for NASA and now known as the VolumeViewer(TradeMark), generates three-dimensional (3D) images of 3D objects in a display volume. This system differs fundamentally from stereoscopic and holographic display systems: The images generated by this system are truly 3D in that they can be viewed from almost any angle, without the aid of special eyeglasses. It is possible to walk around the system while gazing at its display volume to see a displayed object from a changing perspective, and multiple observers standing at different positions around the display can view the object simultaneously from their individual perspectives, as though the displayed object were a real 3D object. At the time of writing this article, only partial information on the design and principle of operation of the system was available. It is known that the system includes a high-speed, silicon-backplane, ferroelectric-liquid-crystal spatial light modulator (SLM), multiple high-power lasers for projecting images in multiple colors, a rotating helix that serves as a moving screen for displaying voxels [volume cells or volume elements, in analogy to pixels (picture cells or picture elements) in two-dimensional (2D) images], and a host computer. The rotating helix and its motor drive are the only moving parts. Under control by the host computer, a stream of 2D image patterns is generated on the SLM and projected through optics onto the surface of the rotating helix. The system utilizes a parallel pixel/voxel-addressing scheme: All the pixels of the 2D pattern on the SLM are addressed simultaneously by laser beams. This parallel addressing scheme overcomes the difficulty of achieving both high resolution and a high frame rate in a raster scanning or serial addressing scheme. It has been reported that the structure of the system is simple and easy to build, that the optical design and alignment are not difficult, and that the
Three dimensional Visualization of Jupiter's Equatorial Region
NASA Technical Reports Server (NTRS)
1997-01-01
Frames from a three dimensional visualization of Jupiter's equatorial region. The images used cover an area of 34,000 kilometers by 11,000 kilometers (about 21,100 by 6,800 miles) near an equatorial 'hotspot' similar to the site where the probe from NASA's Galileo spacecraft entered Jupiter's atmosphere on December 7th, 1995. These features are holes in the bright, reflective, equatorial cloud layer where warmer thermal emission from Jupiter's deep atmosphere can pass through. The circulation patterns observed here along with the composition measurements from the Galileo Probe suggest that dry air may be converging and sinking over these regions, maintaining their cloud-free appearance. The bright clouds to the right of the hotspot as well as the other bright features may be examples of upwelling of moist air and condensation.
This frame is a view to the southeast, from between the cloud layers and over the north center of the region. The tall white clouds in the lower cloud deck are probably much like large terrestrial thunderclouds. They may be regions where atmospheric water powers vertical convection over large horizontal distances.
Galileo is the first spacecraft to image Jupiter in near-infrared light (which is invisible to the human eye) using three filters at 727, 756, and 889 nanometers (nm). Because light at these three wavelengths is absorbed at different altitudes by atmospheric methane, a comparison of the resulting images reveals information about the heights of clouds in Jupiter's atmosphere. This information can be visualized by rendering cloud surfaces with the appropriate height variations.
The visualization reduces Jupiter's true cloud structure to two layers. The height of a high haze layer is assumed to be proportional to the reflectivity of Jupiter at 889 nm. The height of a lower tropospheric cloud is assumed to be proportional to the reflectivity at 727 nm divided by that at 756 nm. This model is overly simplistic, but is based on
Three dimensional Visualization of Jupiter's Equatorial Region
NASA Technical Reports Server (NTRS)
1997-01-01
Frames from a three dimensional visualization of Jupiter's equatorial region. The images used cover an area of 34,000 kilometers by 11,000 kilometers (about 21,100 by 6,800 miles) near an equatorial 'hotspot' similar to the site where the probe from NASA's Galileo spacecraft entered Jupiter's atmosphere on December 7th, 1995. These features are holes in the bright, reflective, equatorial cloud layer where warmer thermal emission from Jupiter's deep atmosphere can pass through. The circulation patterns observed here along with the composition measurements from the Galileo Probe suggest that dry air may be converging and sinking over these regions, maintaining their cloud-free appearance. The bright clouds to the right of the hotspot as well as the other bright features may be examples of upwelling of moist air and condensation.
This frame is a view to the northeast, from between the cloud layers and above the streaks in the lower cloud leading towards the hotspot. The upper haze layer has some features that match the lower cloud, such as the bright streak in the foreground of the frame. These are probably thick clouds that span several tens of vertical kilometers.
Galileo is the first spacecraft to image Jupiter in near-infrared light (which is invisible to the human eye) using three filters at 727, 756, and 889 nanometers (nm). Because light at these three wavelengths is absorbed at different altitudes by atmospheric methane, a comparison of the resulting images reveals information about the heights of clouds in Jupiter's atmosphere. This information can be visualized by rendering cloud surfaces with the appropriate height variations.
The visualization reduces Jupiter's true cloud structure to two layers. The height of a high haze layer is assumed to be proportional to the reflectivity of Jupiter at 889 nm. The height of a lower tropospheric cloud is assumed to be proportional to the reflectivity at 727 nm divided by that at 756 nm. This model is overly
Three dimensional Visualization of Jupiter's Equatorial Region
NASA Technical Reports Server (NTRS)
1997-01-01
Frames from a three dimensional visualization of Jupiter's equatorial region. The images used cover an area of 34,000 kilometers by 11,000 kilometers (about 21,100 by 6,800 miles) near an equatorial 'hotspot' similar to the site where the probe from NASA's Galileo spacecraft entered Jupiter's atmosphere on December 7th, 1995. These features are holes in the bright, reflective, equatorial cloud layer where warmer thermal emission from Jupiter's deep atmosphere can pass through. The circulation patterns observed here along with the composition measurements from the Galileo Probe suggest that dry air may be converging and sinking over these regions, maintaining their cloud-free appearance. The bright clouds to the right of the hotspot as well as the other bright features may be examples of upwelling of moist air and condensation.
This frame is a view to the west, from between the cloud layers and over the patchy white clouds to the east of the hotspot. This is probably an area where moist convection is occurring over large horizontal distances, similar to the atmosphere over the equatorial ocean on Earth. The clouds are high and thick, and are observed to change rapidly over short time scales.
Galileo is the first spacecraft to image Jupiter in near-infrared light (which is invisible to the human eye) using three filters at 727, 756, and 889 nanometers (nm). Because light at these three wavelengths is absorbed at different altitudes by atmospheric methane, a comparison of the resulting images reveals information about the heights of clouds in Jupiter's atmosphere. This information can be visualized by rendering cloud surfaces with the appropriate height variations.
The visualization reduces Jupiter's true cloud structure to two layers. The height of a high haze layer is assumed to be proportional to the reflectivity of Jupiter at 889 nm. The height of a lower tropospheric cloud is assumed to be proportional to the reflectivity at 727 nm divided by that at 756
Three dimensional Visualization of Jupiter's Equatorial Region
NASA Technical Reports Server (NTRS)
1997-01-01
Frames from a three dimensional visualization of Jupiter's equatorial region. The images used cover an area of 34,000 kilometers by 11,000 kilometers (about 21,100 by 6,800 miles) near an equatorial 'hotspot' similar to the site where the probe from NASA's Galileo spacecraft entered Jupiter's atmosphere on December 7th, 1995. These features are holes in the bright, reflective, equatorial cloud layer where warmer thermal emission from Jupiter's deep atmosphere can pass through. The circulation patterns observed here along with the composition measurements from the Galileo Probe suggest that dry air may be converging and sinking over these regions, maintaining their cloud-free appearance. The bright clouds to the right of the hotspot as well as the other bright features may be examples of upwelling of moist air and condensation.
This frame is a view from the southwest looking northeast, from an altitude just above the high haze layer. The streaks in the lower cloud leading towards the hotspot are visible. The upper haze layer is mostly flat, with notable small peaks that can be matched with features in the lower cloud. In reality, these areas may represent a continuous vertical cloud column.
Galileo is the first spacecraft to image Jupiter in near-infrared light (which is invisible to the human eye) using three filters at 727, 756, and 889 nanometers (nm). Because light at these three wavelengths is absorbed at different altitudes by atmospheric methane, a comparison of the resulting images reveals information about the heights of clouds in Jupiter's atmosphere. This information can be visualized by rendering cloud surfaces with the appropriate height variations.
The visualization reduces Jupiter's true cloud structure to two layers. The height of a high haze layer is assumed to be proportional to the reflectivity of Jupiter at 889 nm. The height of a lower tropospheric cloud is assumed to be proportional to the reflectivity at 727 nm divided by that at 756
Three dimensional Visualization of Jupiter's Equatorial Region
NASA Technical Reports Server (NTRS)
1997-01-01
Frames from a three dimensional visualization of Jupiter's equatorial region. The images used cover an area of 34,000 kilometers by 11,000 kilometers (about 21,100 by 6,800 miles) near an equatorial 'hotspot' similar to the site where the probe from NASA's Galileo spacecraft entered Jupiter's atmosphere on December 7th, 1995. These features are holes in the bright, reflective, equatorial cloud layer where warmer thermal emission from Jupiter's deep atmosphere can pass through. The circulation patterns observed here along with the composition measurements from the Galileo Probe suggest that dry air may be converging and sinking over these regions, maintaining their cloud-free appearance. The bright clouds to the right of the hotspot as well as the other bright features may be examples of upwelling of moist air and condensation.
This frame is a view to the northeast, from between the cloud layers and above the streaks in the lower cloud leading towards the hotspot. The hotspot is clearly visible as a deep blue feature. The cloud streaks end near the hotspot, consistent with the idea that clouds traveling along these streak lines descend and evaporate as they approach the hotspot. The upper haze layer is slightly bowed upwards above the hotspot.
Galileo is the first spacecraft to image Jupiter in near-infrared light (which is invisible to the human eye) using three filters at 727, 756, and 889 nanometers (nm). Because light at these three wavelengths is absorbed at different altitudes by atmospheric methane, a comparison of the resulting images reveals information about the heights of clouds in Jupiter's atmosphere. This information can be visualized by rendering cloud surfaces with the appropriate height variations.
The visualization reduces Jupiter's true cloud structure to two layers. The height of a high haze layer is assumed to be proportional to the reflectivity of Jupiter at 889 nm. The height of a lower tropospheric cloud is assumed to be proportional
Three dimensional Visualization of Jupiter's Equatorial Region
NASA Technical Reports Server (NTRS)
1997-01-01
Frames from a three dimensional visualization of Jupiter's equatorial region. The images used cover an area of 34,000 kilometers by 11,000 kilometers (about 21,100 by 6,800 miles) near an equatorial 'hotspot' similar to the site where the probe from NASA's Galileo spacecraft entered Jupiter's atmosphere on December 7th, 1995. These features are holes in the bright, reflective, equatorial cloud layer where warmer thermal emission from Jupiter's deep atmosphere can pass through. The circulation patterns observed here along with the composition measurements from the Galileo Probe suggest that dry air may be converging and sinking over these regions, maintaining their cloud-free appearance. The bright clouds to the right of the hotspot as well as the other bright features may be examples of upwelling of moist air and condensation.
This frame is a view from above and to the south of the visualized area, showing the entire model. The entire region is overlain by a thin, transparent haze. In places the haze is high and thick, especially to the east (to the right of) the hotspot.
Galileo is the first spacecraft to image Jupiter in near-infrared light (which is invisible to the human eye) using three filters at 727, 756, and 889 nanometers (nm). Because light at these three wavelengths is absorbed at different altitudes by atmospheric methane, a comparison of the resulting images reveals information about the heights of clouds in Jupiter's atmosphere. This information can be visualized by rendering cloud surfaces with the appropriate height variations.
The visualization reduces Jupiter's true cloud structure to two layers. The height of a high haze layer is assumed to be proportional to the reflectivity of Jupiter at 889 nm. The height of a lower tropospheric cloud is assumed to be proportional to the reflectivity at 727 nm divided by that at 756 nm. This model is overly simplistic, but is based on more sophisticated studies of Jupiter's cloud structure. The upper
Pathogen Propagation in Cultured Three-Dimensional Tissue Mass
NASA Technical Reports Server (NTRS)
Goodwin, Thomas J. (Inventor); Spaulding, Glenn F. (Inventor); Wolf, David A. (Inventor)
2000-01-01
A process for propagating a pathogen in a three-dimensional tissue mass cultured at microgravity conditions in a culture vessel containing culture media and a culture matrix is provided. The three-dimensional tissue mass is inoculated with a pathogen and pathogen replication in the cells of the tissue mass achieved.
Three-dimensional imaging of the myocardium with isotopes
NASA Technical Reports Server (NTRS)
Budinger, T. F.
1975-01-01
Three methods of imaging the three-dimensional distribution of isotopes in the myocardium are discussed. Three-dimensional imaging was examined using multiple Anger-camera views. Longitudinal tomographic images with compensation for blurring were studied. Transverse-section reconstruction using coincidence detection of annihilation gammas from positron emitting isotopes was investigated.
Pathogen propagation in cultured three-dimensional tissue mass
NASA Technical Reports Server (NTRS)
Goodwin, Thomas J. (Inventor); Spaulding, Glenn F. (Inventor); Wolf, David A. (Inventor)
2000-01-01
A process for propagating a pathogen in a three-dimensional tissue mass cultured at microgravity conditions in a culture vessel containing culture media and a culture matrix is provided. The three-dimensional tissue mass is inoculated with a pathogen and pathogen replication in the cells of the tissue mass achieved.
Computer-Generated, Three-Dimensional Character Animation.
ERIC Educational Resources Information Center
Van Baerle, Susan Lynn
This master's thesis begins by discussing the differences between 3-D computer animation of solid three-dimensional, or monolithic, objects, and the animation of characters, i.e., collections of movable parts with soft pliable surfaces. Principles from two-dimensional character animation that can be transferred to three-dimensional character…
Scanning holographic microscopy of three-dimensional fluorescent specimens
Indebetouw, Guy; Zhong, Wenwei
2006-01-01
We demonstrate experimentally the three-dimensional reconstructions of fluorescent biological specimens using scanning holographic microscopy. Three-dimensional reconstructions with transverse resolution below about 1 μm of transmission and fluorescence emission images are presented and analyzed. The limitations of the method are discussed. PMID:16783434
Using three-dimensional spacetime diagrams in special relativity
NASA Astrophysics Data System (ADS)
Dray, Tevian
2013-08-01
We provide three examples of the use of geometric reasoning with three-dimensional spacetime diagrams, rather than algebraic manipulations using three-dimensional Lorentz transformations, to analyze problems in special relativity. The examples are the "rising manhole" paradox, the "moving spotlight" problem, and Einstein's light-clock derivation of time dilation.
Wataganara, Tuangsit; Sutanthavibool, Anuwat; Limwongse, Chanin
2006-10-01
Generalized shortening of fetal long bones detected from prenatal sonographic examination usually raise a tentative diagnosis of skeletal dysplasia. Information obtained from grey-scale scan is frequently not sufficient to provide a definite diagnosis, and the images are not readily comprehensible for the parents-to-be. Lately, three-dimensional sonography has become increasing available in obstetric practice. The authors report here a rare case of fetal achondrogenesis, which is a lethal form of skeletal dysplasia, in a 30-week-old fetus using real-time three-dimensional ultrasound. The prenatal findings of fetal achondrogenesis from this technique were thoroughly described, along with postnatal radiography and autopsy results. Sonographic features from this imaging technique allow for an accurate diagnosis and better understanding of the parents. This facilitates the genetic counseling process, as well as the parental options for further care.
A comparison of two- and three-dimensional imaging
NASA Astrophysics Data System (ADS)
Hall, Ernest; Rosselot, Donald; Aull, Mark; Balapa, Manohar
2006-10-01
Three dimensional visual recognition and measurement are important in many machine vision applications. In some cases, a stationary camera base is used and a three-dimensional model will permit the measurement of depth information from a scene. One important special case is stereo vision for human visualization or measurements. In cases in which the camera base is also in motion, a seven dimensional model may be used. Such is the case for navigation of an autonomous mobile robot. The purpose of this paper is to provide a computational view and introduction of three methods to three-dimensional vision. Models are presented for each situation and example computations and images are presented. The significance of this work is that it shows that various methods based on three-dimensional vision may be used for solving two and three dimensional vision problems. We hope this work will be slightly iconoclastic but also inspirational by encouraging further research in optical engineering.
Radiative transfer for a three-dimensional raining cloud
NASA Technical Reports Server (NTRS)
Haferman, J. L.; Krajewski, W. F.; Smith, T. F.; Sanchez, A.
1993-01-01
Satellite-sensor-based microwave brightness temperatures for a three-dimensional raining cloud over a reflecting surface are computed by using a radiative transfer model based on the discrete-ordinates solution procedure. The three-dimensional model applied to a plane layer is validated by comparison with results from a one-dimensional model that is available in the literature. Results examining the effects of cloud height, rainfall rate, surface reflectance, rainfall footprint area, and satellite viewing position on one- and three-dimensional brightness temperature calculations are reported. The numerical experiments indicate that, under certain conditions, three-dimensional effects are significant in the analysis of satellite-sensor-based rainfall retrieval algorithms. The results point to the need to consider carefully three-dimensional effects as well as surface reflectance effects when interpreting satellite-measured radiation data.
Virtual three-dimensional blackboard: three-dimensional finger tracking with a single camera
NASA Astrophysics Data System (ADS)
Wu, Andrew; Hassan-Shafique, Khurram; Shah, Mubarak; da Vitoria Lobo, N.
2004-01-01
We present a method for three-dimensional (3D) tracking of a human finger from a monocular sequence of images. To recover the third dimension from the two-dimensional images, we use the fact that the motion of the human arm is highly constrained owing to the dependencies between elbow and forearm and the physical constraints on joint angles. We use these anthropometric constraints to derive a 3D trajectory of a gesticulating arm. The system is fully automated and does not require human intervention. The system presented can be used as a visualization tool, as a user-input interface, or as part of some gesture-analysis system in which 3D information is important.
Three-Dimensional Mid-Air Acoustic Manipulation by Ultrasonic Phased Arrays
Ochiai, Yoichi; Hoshi, Takayuki; Rekimoto, Jun
2014-01-01
The essence of levitation technology is the countervailing of gravity. It is known that an ultrasound standing wave is capable of suspending small particles at its sound pressure nodes. The acoustic axis of the ultrasound beam in conventional studies was parallel to the gravitational force, and the levitated objects were manipulated along the fixed axis (i.e. one-dimensionally) by controlling the phases or frequencies of bolted Langevin-type transducers. In the present study, we considered extended acoustic manipulation whereby millimetre-sized particles were levitated and moved three-dimensionally by localised ultrasonic standing waves, which were generated by ultrasonic phased arrays. Our manipulation system has two original features. One is the direction of the ultrasound beam, which is arbitrary because the force acting toward its centre is also utilised. The other is the manipulation principle by which a localised standing wave is generated at an arbitrary position and moved three-dimensionally by opposed and ultrasonic phased arrays. We experimentally confirmed that expanded-polystyrene particles of 0.6 mm, 1 mm, and 2 mm in diameter could be manipulated by our proposed method. PMID:24849371
Three-dimensional mid-air acoustic manipulation by ultrasonic phased arrays.
Ochiai, Yoichi; Hoshi, Takayuki; Rekimoto, Jun
2014-01-01
The essence of levitation technology is the countervailing of gravity. It is known that an ultrasound standing wave is capable of suspending small particles at its sound pressure nodes. The acoustic axis of the ultrasound beam in conventional studies was parallel to the gravitational force, and the levitated objects were manipulated along the fixed axis (i.e. one-dimensionally) by controlling the phases or frequencies of bolted Langevin-type transducers. In the present study, we considered extended acoustic manipulation whereby millimetre-sized particles were levitated and moved three-dimensionally by localised ultrasonic standing waves, which were generated by ultrasonic phased arrays. Our manipulation system has two original features. One is the direction of the ultrasound beam, which is arbitrary because the force acting toward its centre is also utilised. The other is the manipulation principle by which a localised standing wave is generated at an arbitrary position and moved three-dimensionally by opposed and ultrasonic phased arrays. We experimentally confirmed that expanded-polystyrene particles of 0.6 mm, 1 mm, and 2 mm in diameter could be manipulated by our proposed method.
NASA Astrophysics Data System (ADS)
Klyen, Blake R.; Shavlakadze, Thea; Radley-Crabb, Hannah G.; Grounds, Miranda D.; Sampson, David D.
2011-07-01
Three-dimensional optical coherence tomography (3D-OCT) was used to image the structure and pathology of skeletal muscle tissue from the treadmill-exercised mdx mouse model of human Duchenne muscular dystrophy. Optical coherence tomography (OCT) images of excised muscle samples were compared with co-registered hematoxylin and eosin-stained and Evans blue dye fluorescence histology. We show, for the first time, structural 3D-OCT images of skeletal muscle dystropathology well correlated with co-located histology. OCT could identify morphological features of interest and necrotic lesions within the muscle tissue samples based on intrinsic optical contrast. These findings demonstrate the utility of 3D-OCT for the evaluation of small-animal skeletal muscle morphology and pathology, particularly for studies of mouse models of muscular dystrophy.
Three-dimensional aerodynamic shape optimization using discrete sensitivity analysis
NASA Technical Reports Server (NTRS)
Burgreen, Gregory W.
1995-01-01
An aerodynamic shape optimization procedure based on discrete sensitivity analysis is extended to treat three-dimensional geometries. The function of sensitivity analysis is to directly couple computational fluid dynamics (CFD) with numerical optimization techniques, which facilitates the construction of efficient direct-design methods. The development of a practical three-dimensional design procedures entails many challenges, such as: (1) the demand for significant efficiency improvements over current design methods; (2) a general and flexible three-dimensional surface representation; and (3) the efficient solution of very large systems of linear algebraic equations. It is demonstrated that each of these challenges is overcome by: (1) employing fully implicit (Newton) methods for the CFD analyses; (2) adopting a Bezier-Bernstein polynomial parameterization of two- and three-dimensional surfaces; and (3) using preconditioned conjugate gradient-like linear system solvers. Whereas each of these extensions independently yields an improvement in computational efficiency, the combined effect of implementing all the extensions simultaneously results in a significant factor of 50 decrease in computational time and a factor of eight reduction in memory over the most efficient design strategies in current use. The new aerodynamic shape optimization procedure is demonstrated in the design of both two- and three-dimensional inviscid aerodynamic problems including a two-dimensional supersonic internal/external nozzle, two-dimensional transonic airfoils (resulting in supercritical shapes), three-dimensional transport wings, and three-dimensional supersonic delta wings. Each design application results in realistic and useful optimized shapes.
Three-dimensional imaging of the uterus: The value of the coronal plane
Wong, Lufee; White, Nikki; Ramkrishna, Jayshree; Júnior, Edward Araujo; Meagher, Simon; Costa, Fabricio Da Silva
2015-01-01
Advent in three-dimensional (3D) imaging technology has seen 3D ultrasound establish itself as a useful adjunct complementary to traditional two-dimensional imaging of the female pelvis. This advantage largely arises from its ability to reconstruct the coronal plane of the uterus, which allows further delineation of many gynecological disorders. 3D imaging of the uterus is now the preferred imaging modality for assessing congenital uterine anomalies and intrauterine device localization. Newer indications include the diagnosis of adenomyosis. It can also add invaluable information to delineate other endometrial and myometrial pathology such as fibroids and endometrial polyps. PMID:26753063
Numerical Modeling of Three-Dimensional Confined Flows
NASA Technical Reports Server (NTRS)
Greywall, M. S.
1981-01-01
A three dimensional confined flow model is presented. The flow field is computed by calculating velocity and enthalpy along a set of streamlines. The finite difference equations are obtained by applying conservation principles to streamtubes constructed around the chosen streamlines. With appropriate substitutions for the body force terms, the approach computes three dimensional magnetohydrodynamic channel flows. A listing of a computer code, based on this approach is presented in FORTRAN IV language. The code computes three dimensional compressible viscous flow through a rectangular duct, with the duct cross section specified along the axis.
Three-dimensional particle imaging by wavefront sensing.
Towers, Catherine E; Towers, David P; Campbell, Heather I; Zhang, Sijiong; Greenaway, Alan H
2006-05-01
We present two methods for three-dimensional particle metrology from a single two-dimensional view. The techniques are based on wavefront sensing where the three-dimensional location of a particle is encoded into a single image plane. The first technique is based on multiplanar imaging, and the second produces three-dimensional location information via anamorphic distortion of the recorded images. Preliminary results show that an uncertainty of 8 microm in depth can be obtained for low-particle density over a thin plane, and an uncertainty of 30 microm for higher particle density over a 10 mm deep volume.
More About The Farley Three-Dimensional Braider
NASA Technical Reports Server (NTRS)
Farley, Gary L.
1993-01-01
Farley three-dimensional braider, undergoing development, is machine for automatic fabrication of three-dimensional braided structures. Incorporates yarns into structure at arbitrary braid angles to produce complicated shape. Braiding surface includes movable braiding segments containing pivot points, along which yarn carriers travel during braiding process. Yarn carrier travels along sequence of pivot points as braiding segments move. Combined motions position yarns for braiding onto preform. Intended for use in making fiber preforms for fiber/matrix composite parts, such as multiblade propellers. Machine also described in "Farley Three-Dimensional Braiding Machine" (LAR-13911).
Interactive dynamic three-dimensional scene for the ground-based three-dimensional display
NASA Astrophysics Data System (ADS)
Hou, Peining; Sang, Xinzhu; Guo, Nan; Chen, Duo; Yan, Binbin; Wang, Kuiru; Dou, Wenhua; Xiao, Liquan
2016-10-01
Three-dimensional (3D) displays provides valuable tools for many fields, such as scientific experiment, education, information transmission, medical imaging and physical simulation. Ground based 360° 3D display with dynamic and controllable scene can find some special applications, such as design and construction of buildings, aeronautics, military sand table and so on. It can be utilized to evaluate and visualize the dynamic scene of the battlefield, surgical operation and the 3D canvas of art. In order to achieve the ground based 3D display, the public focus plane should be parallel to the camera's imaging planes, and optical axes should be offset to the center of public focus plane in both vertical and horizontal directions. Virtual cameras are used to display 3D dynamic scene with Unity 3D engine. Parameters of virtual cameras for capturing scene are designed and analyzed, and locations of virtual cameras are determined by the observer's eye positions in the observing space world. An interactive dynamic 3D scene for ground based 360° 3D display is demonstrated, which provides high-immersion 3D visualization.
Three-dimensional reconstructions of solid surfaces using conventional microscopes.
Ficker, Tomáš; Martišek, Dalibor
2016-01-01
The three-dimensional digital replicas of solid surfaces are subject of interest of different branches of science and technology. The present paper in its introductory parts brings an overview of the various microscopic reconstructive techniques based on optical sectioning. The main attention is devoted to conventional reconstruction methods and especially to that one employing the Fourier transform. The three-dimensional replicas of this special reconstructive frequency method are compared graphically and numerically with the three-dimensional replicas of the confocal method. Based on the comparative study it has been concluded that the quality of the conventional replicas of surfaces possessing textures of intermediate height irregularities is acceptable and almost comparable with the quality of confocal replicas. This study is relevant both for identifying a convenient technique that provides good qualities of three-dimensional replicas and for selecting the hardware whose price is affordable even for small research groups studying rougher surface textures.
Direct Linear Transformation Method for Three-Dimensional Cinematography
ERIC Educational Resources Information Center
Shapiro, Robert
1978-01-01
The ability of Direct Linear Transformation Method for three-dimensional cinematography to locate points in space was shown to meet the accuracy requirements associated with research on human movement. (JD)
Three-dimensional Simulation of Backward Raman Amplification
A.A. Balakin; G.M. Fraiman; N.J. Fisch
2005-11-12
Three-dimensional (3-D) simulations for the Backward Raman Amplification (BRA) are presented. The images illustrate the effects of pump depletion, pulse diffraction, non-homogeneous plasma density, and plasma ionization.
Improving Students' Sense of Three-Dimensional Shapes.
ERIC Educational Resources Information Center
Leeson, Neville J.
1994-01-01
Describes activities to be used with fifth and sixth graders to improve students' spatial sense with respect to three-dimensional shapes. Includes the use of cubes, triangular prisms, tetrahedrons, and square pyramids. (MKR)
Analysis and validation of carbohydrate three-dimensional structures
Lütteke, Thomas
2009-02-01
The article summarizes the information that is gained from and the errors that are found in carbohydrate structures in the Protein Data Bank. Validation tools that can locate these errors are described. Knowledge of the three-dimensional structures of the carbohydrate molecules is indispensable for a full understanding of the molecular processes in which carbohydrates are involved, such as protein glycosylation or protein–carbohydrate interactions. The Protein Data Bank (PDB) is a valuable resource for three-dimensional structural information on glycoproteins and protein–carbohydrate complexes. Unfortunately, many carbohydrate moieties in the PDB contain inconsistencies or errors. This article gives an overview of the information that can be obtained from individual PDB entries and from statistical analyses of sets of three-dimensional structures, of typical problems that arise during the analysis of carbohydrate three-dimensional structures and of the validation tools that are currently available to scientists to evaluate the quality of these structures.
A fusion algorithm for building three-dimensional maps
NASA Astrophysics Data System (ADS)
Vokhmintsev, A.; Makovetskii, A.; Kober, V.; Sochenkov, I.; Kuznetsov, V.
2015-09-01
Recently various algorithms for building of three-dimensional maps of indoor environments have been proposed. In this work we use a Kinect camera that captures RGB images along with depth information for building three-dimensional dense maps of indoor environments. Commonly mapping systems consist of three components; that is, first, spatial alignment of consecutive data frames; second, detection of loop-closures, and finally, globally consistent alignment of the data sequence. It is known that three-dimensional point clouds are well suited for frame-to-frame alignment and for three-dimensional dense reconstruction without the use of valuable visual RGB information. A new fusion algorithm combining visual features and depth information for loop-closure detection followed by pose optimization to build global consistent maps is proposed. The performance of the proposed system in real indoor environments is presented and discussed.
Construction of Three Dimensional Solutions for the Maxwell Equations
NASA Technical Reports Server (NTRS)
Yefet, A.; Turkel, E.
1998-01-01
We consider numerical solutions for the three dimensional time dependent Maxwell equations. We construct a fourth order accurate compact implicit scheme and compare it to the Yee scheme for free space in a box.
Three-dimensional pattern transfer and nanolithography: modified soft molding
NASA Astrophysics Data System (ADS)
Kim, Y. S.; Park, Joonhyung; Lee, Hong H.
2002-08-01
One-step transfer of molded three-dimensional polymer structures into underlying substrate is reported. The one-step transfer is made possible by a molding technique presented here in the form of modified soft molding. Formation of a desired three-dimensional structure in a polymer film by this method, followed by one-step reactive ion etching, is utilized for the transfer. The technique is also shown to be effective in transferring sub-100-nm features.
Uniform Deterministic Discrete Method for three dimensional systems
NASA Astrophysics Data System (ADS)
Li, Ben-Wen; Tao, Wen-Quan; Nie, Yu-Hong
1997-06-01
For radiative direct exchange areas in three dimensional system, the Uniform Deterministic Discrete Method (UDDM) was adopted. The spherical surface dividing method for sending area element and the regular icosahedron for sending volume element can meet with the direct exchange area computation of any kind of zone pairs. The numerical examples of direct exchange area in three dimensional system with nonhomogeneous attenuation coefficients indicated that the UDDM can give very high numerical accuracy.
Three-dimensional study of the multi-cavity FEL
Krishnagopal, S.; Kumar, V.
1995-12-31
The Multi-Cavity Free-Electron Laser has been proposed earlier, as a new configuration to obtain short, intense pulses of radiation, the key idea being to pre-bunch the electron beam in a number of very short cavities. Those studies were one-dimensional. Here we use three-dimensional simulations to study the viability of this concept when three-dimensional effects are included, particularly with regard to the transverse modes of the optical beam.
Nonlinear wave interaction problems in the three-dimensional case
NASA Astrophysics Data System (ADS)
Curró, C.; Manganaro, N.; Pavlov, M. V.
2017-01-01
Three-dimensional nonlinear wave interactions have been analytically described. The procedure under interest can be applied to three-dimensional quasilinear systems of first order, whose hydrodynamic reductions are homogeneous semi-Hamiltonian hydrodynamic type systems (i.e. possess diagonal form and infinitely many conservation laws). The interaction of N waves was studied. In particular we prove that they behave like simple waves and they distort after the collision region. The amount of the distortion can be analytically computed.
Effect of three-dimensionality on compressible mixing
Papamoschou, D. )
1992-02-01
Existing experimental data and hypotheses on the growth rates of compressible and incompressible turbulent shear layers are used to estimate the effect of three-dimensionality in the turbulent mixing enhancement in compressible shear flows that is critically important to the efficiency of scramjet powerplants. The general trend is found to be a decrease in growth rate with increasing three-dimensionality, excepting only the restricted regime, where the growth-rate increase is modest. 9 refs.
Initialization and Simulation of Three-Dimensional Aircraft Wake Vortices
NASA Technical Reports Server (NTRS)
Ash, Robert L.; Zheng, Z. C.
1997-01-01
This paper studies the effects of axial velocity profiles on vortex decay, in order to properly initialize and simulate three-dimensional wake vortex flow. Analytical relationships are obtained based on a single vortex model and computational simulations are performed for a rather practical vortex wake, which show that the single vortex analytical relations can still be applicable at certain streamwise sections of three-dimensional wake vortices.
Barros, Fernanda S; Araujo Júnior, Edward; Rolo, Liliam Cristine; Nardozza, Luciano Marcondes Machado
2012-01-01
Lethal multiple pterygium (LMP) is a series of disorders of fetal formation with a heterogeneous range of manifestations that generally include cystic hygroma, pulmonary hypoplasia, cleft palate, cryptorchidism, joint contractures, fetal akinesia, heart defects, growth restriction, and intestinal malrotation. The prenatal diagnosis of this syndrome is suspected when two-dimensional ultrasound (2DUS) scan shows several malformations.. The three-dimensional ultrasound (3DUS) in rendering mode permits the spatial visualization of these malformations, allowing better understanding of this anomaly by parents. We report a case of a fetus in the second trimester with multiple abnormalities suggestive of LMP that were identified using 2DUS, and emphasize the importance of 3DUS in counseling the parents.
Ordered three-dimensional interconnected nanoarchitectures in anodic porous alumina
Martín, Jaime; Martín-González, Marisol; Fernández, Jose Francisco; Caballero-Calero, Olga
2014-01-01
Three-dimensional nanostructures combine properties of nanoscale materials with the advantages of being macro-sized pieces when the time comes to manipulate, measure their properties, or make a device. However, the amount of compounds with the ability to self-organize in ordered three-dimensional nanostructures is limited. Therefore, template-based fabrication strategies become the key approach towards three-dimensional nanostructures. Here we report the simple fabrication of a template based on anodic aluminum oxide, having a well-defined, ordered, tunable, homogeneous 3D nanotubular network in the sub 100 nm range. The three-dimensional templates are then employed to achieve three-dimensional, ordered nanowire-networks in Bi2Te3 and polystyrene. Lastly, we demonstrate the photonic crystal behavior of both the template and the polystyrene three-dimensional nanostructure. Our approach may establish the foundations for future high-throughput, cheap, photonic materials and devices made of simple commodity plastics, metals, and semiconductors. PMID:25342247
Integrated Aeromechanics with Three-Dimensional Solid-Multibody Structures
NASA Technical Reports Server (NTRS)
Datta, Anubhav; Johnson, Wayne
2014-01-01
A full three-dimensional finite element-multibody structural dynamic solver is coupled to a three-dimensional Reynolds-averaged Navier-Stokes solver for the prediction of integrated aeromechanical stresses and strains on a rotor blade in forward flight. The objective is to lay the foundations of all major pieces of an integrated three-dimensional rotor dynamic analysis - from model construction to aeromechanical solution to stress/strain calculation. The primary focus is on the aeromechanical solution. Two types of three-dimensional CFD/CSD interfaces are constructed for this purpose with an emphasis on resolving errors from geometry mis-match so that initial-stage approximate structural geometries can also be effectively analyzed. A three-dimensional structural model is constructed as an approximation to a UH-60A-like fully articulated rotor. The aerodynamic model is identical to the UH-60A rotor. For preliminary validation measurements from a UH-60A high speed flight is used where CFD coupling is essential to capture the advancing side tip transonic effects. The key conclusion is that an integrated aeromechanical analysis is indeed possible with three-dimensional structural dynamics but requires a careful description of its geometry and discretization of its parts.
Komwilaisak, Ratana; Ratanasiri, Thawalwong; Kleebkaow, Pilaiwan
2004-10-01
The accurate diagnosis of fetal malformations in utero can provide both heath care providers and parents a number of management options. Three-dimensional ultrasonography is a new technique of diagnosis which has several potential advantages to allow for evaluation of specific anomalies by permitting high-quality views of body surface. We report 4 cases of fetal chromosomal abnormalities including 2 cases of trisomy 21, 1 case of trisomy 13 and 1 case of 48, XXY/+18. All cases were proved to have abnormal chromosomes by amniocentesis or percutaneous umbilical cord blood sampling. After 3D reconstruction, we can identify specific facial abnormalities which can not be visualized by conventional two-dimensional ultrasound such as low set ear Mongolian's slant eyes, facial dysmorphism of trisomy 13 and trisomy 18. We also clearly visualized abnormalities of digits such as overlapping fingers, club hands and sandal gap. Three-dimensional reconstruction of the fetal body surface improves the antenatal diagnosis of chromosomal abnormalities characterized by a particular dysmorphism. Our report suggests that three-dimensional ultrasonography has the potential to provide novel informations on the fetal anatomy and be useful in visualization and identification of chromosomal abnormalities in utero.
Delcker; Turowski
1997-12-01
We report two cases of intracranial aneurysms to give an impression of the use of three-dimensional (3-D) transcranial duplex sonography in combination with the application of a transpulmonary stable contrast agent. Data acquisition was performed with a free-hand scanning of the transducer (2 MHz) and a prototype of a new magnetic sensor system to track the spatial orientation of the ultrasound probe while scanning the volume of interest. The 3-D data were stored and afterwards 3-D reconstructions performed. Three-dimensional transcranial color duplex system with power Doppler mode showed an exact spatial orientation of the intracranial arteries. The three-dimensional system lets the reader retrospectively choose the section plane through the 3-D data set, and the reconstructions through the data set allowed us to localize aneurysms in both cases. The increased freedom of movement of the transducer allows the sonographer to maintain transducer contact with the skin, while offering the freedom to move the transducer as needed to remain on the acoustic window. Copyright 1997 Elsevier Science Ireland Ltd.
Pooh, Ritsuko Kimata; Kurjak, Asim
2015-03-01
Recent development of three-dimensional (3D) high definition (HD) ultrasound has resulted in remarkable progress in visualization of early embryos and fetuses in sonoembryology. The new technology of HDlive assesses both structural and functional developments in the first trimester with greater reliably than two-dimensional (2D) ultrasound. The ability to visualize not only fetal face, hands, fingers, feet, and toes, but also amniotic membranes, is better with volumetric ultrasound than 2D ultrasound. In this article, detailed and comprehensive structures of normal and abnormal fetuses depicted by 3D HDlive are presented, including various faces of Down's syndrome and holoprosencephaly, as well as low-set ear and finger/toe abnormalities from the first trimester. Three-dimensional HDlive further "humanizes" the fetus, enables detailed observation of the fetal face in the first trimester as shown in this article, and reveals that a small fetus is not more a fetus but a "person" from the first trimester. There has been an immense acceleration in understanding of early human development. The anatomy and physiology of embryonic development is a field where medicine exerts greatest impact on early pregnancy at present, and it opens fascinating aspects of embryonic differentiation. Clinical assessment of those stages of growth relies heavily on 3D/four-dimensional (4D) HDlive, one of the most promising forms of noninvasive diagnostics and embryological phenomena, once matters for textbooks are now routinely recorded with outstanding clarity. New advances deserve the adjective "breathtaking", including 4D parallel study of the structural and functional early human development.
Shawkey, Matthew D.; Saranathan, Vinodkumar; Pálsdóttir, Hildur; Crum, John; Ellisman, Mark H.; Auer, Manfred; Prum, Richard O.
2009-01-01
Organismal colour can be created by selective absorption of light by pigments or light scattering by photonic nanostructures. Photonic nanostructures may vary in refractive index over one, two or three dimensions and may be periodic over large spatial scales or amorphous with short-range order. Theoretical optical analysis of three-dimensional amorphous nanostructures has been challenging because these structures are difficult to describe accurately from conventional two-dimensional electron microscopy alone. Intermediate voltage electron microscopy (IVEM) with tomographic reconstruction adds three-dimensional data by using a high-power electron beam to penetrate and image sections of material sufficiently thick to contain a significant portion of the structure. Here, we use IVEM tomography to characterize a non-iridescent, three-dimensional biophotonic nanostructure: the spongy medullary layer from eastern bluebird Sialia sialis feather barbs. Tomography and three-dimensional Fourier analysis reveal that it is an amorphous, interconnected bicontinuous matrix that is appropriately ordered at local spatial scales in all three dimensions to coherently scatter light. The predicted reflectance spectra from the three-dimensional Fourier analysis are more precise than those predicted by previous two-dimensional Fourier analysis of transmission electron microscopy sections. These results highlight the usefulness, and obstacles, of tomography in the description and analysis of three-dimensional photonic structures. PMID:19158016
NASA Astrophysics Data System (ADS)
Deán-Ben, X. L.; Buehler, Andreas; Ntziachristos, Vasilis; Razansky, Daniel
2013-03-01
Optoacoustic imaging offers the unique capability of simultaneous excitation of a three-dimensional (volumetric) region with a single interrogating laser pulse. In this way, three-dimensional imaging with single-shot illumination is theoretically achievable, which in principle allows the visualization of dynamic events at a high frame rate mainly limited by the pulse repetition rate of the laser. Simultaneous acquisition of optoacoustic signals at a set of points surrounding the imaging sample is however required for this purpose, which is hampered by several technical limitations related to lack of appropriate ultrasound detection technology, digital sampling and processing capacities. Also, a convenient reconstruction algorithm must be selected to accurately image the distribution of the optical absorption from the acquired signals. Specifically, the resolution and quantitativeness of the images depend on the reconstruction procedure employed. Herein we describe an accurate three-dimensional model-based optoacoustic reconstruction algorithm based on a convenient discretization of the analytical solution of the forward model. Subsequent algebraic inversion is done with the LSQR algorithm. The performance of the algorithm is showcased by reconstructing an excised mouse heart with a custom made three-dimensional optoacoustic imaging system. In this system, 256 optoacoustic signals corresponding to single-shot excitation are simultaneously collected with an array of ultrasonic transducers disposed on a spherical surface, which allows three-dimensional imaging at a frame rate of 10 Hz.
NASA Astrophysics Data System (ADS)
Christopher, Lauren A.; Delp, Edward J.
2014-07-01
This paper examines three Bayesian statistical segmentation techniques with an innovative attenuation compensation on synthetic data and breast ultrasound medical images. All use expectation maximization for estimating the Gaussian model parameters and segment the data using a three-dimensional (3-D) Markov random field pixel neighborhood. This paper compares three Bayesian segmentation techniques: maximum a posteriori simulated annealing (MAP-SA), MAP iterated conditional modes (MAP-ICM), and maximization of posterior marginals (MPM). We conclude that because of the high speckle noise and adverse attenuation challenges of breast ultrasound, the MPM algorithm has the best performance. This is due to better localized segmentation than the other MAP techniques. We present results first with synthetic images then with breast ultrasound. Our new contributions for a 3-D breast ultrasound produce improved results using a model of the noise, in which the Gaussian mean is proportional to the image attenuation with depth, combined with a new prior probability model.
A moving observer in a three-dimensional world
2016-01-01
For many tasks such as retrieving a previously viewed object, an observer must form a representation of the world at one location and use it at another. A world-based three-dimensional reconstruction of the scene built up from visual information would fulfil this requirement, something computer vision now achieves with great speed and accuracy. However, I argue that it is neither easy nor necessary for the brain to do this. I discuss biologically plausible alternatives, including the possibility of avoiding three-dimensional coordinate frames such as ego-centric and world-based representations. For example, the distance, slant and local shape of surfaces dictate the propensity of visual features to move in the image with respect to one another as the observer's perspective changes (through movement or binocular viewing). Such propensities can be stored without the need for three-dimensional reference frames. The problem of representing a stable scene in the face of continual head and eye movements is an appropriate starting place for understanding the goal of three-dimensional vision, more so, I argue, than the case of a static binocular observer. This article is part of the themed issue ‘Vision in our three-dimensional world’. PMID:27269608
Biodynamic profiling of three-dimensional tissue growth techniques
NASA Astrophysics Data System (ADS)
Sun, Hao; Merrill, Dan; Turek, John; Nolte, David
2016-03-01
Three-dimensional tissue culture presents a more biologically relevant environment in which to perform drug development than conventional two-dimensional cell culture. However, obtaining high-content information from inside three dimensional tissue has presented an obstacle to rapid adoption of 3D tissue culture for pharmaceutical applications. Biodynamic imaging is a high-content three-dimensional optical imaging technology based on low-coherence interferometry and digital holography that uses intracellular dynamics as high-content image contrast. In this paper, we use biodynamic imaging to compare pharmaceutical responses to Taxol of three-dimensional multicellular spheroids grown by three different growth techniques: rotating bioreactor, hanging-drop and plate-grown spheroids. The three growth techniques have systematic variations among tissue cohesiveness and intracellular activity and consequently display different pharmacodynamics under identical drug dose conditions. The in vitro tissue cultures are also compared to ex vivo living biopsies. These results demonstrate that three-dimensional tissue cultures are not equivalent, and that drug-response studies must take into account the growth method.
Visualization techniques for improved orientation in three-dimensional echocardiography
NASA Astrophysics Data System (ADS)
Wolf, Ivo; de Simone, Raffaele; Hastenteufel, Mark; Mottl-Link, Sibylle; Meinzer, Hans-Peter
2002-05-01
Repair of a defect heart valve is of great advantage for the patient in comparison to replacement with a prosthesis. The applicability and the success of heart valve repair can be improved by an exact diagnosis of the valve's pathological modification. The best way for imaging heart valve insufficiencies is echocardiography, since it is fast, relatively cheap, can be used intraoperatively and provides information about morphology as well as blood flow. Three-dimensional echocardiography has been proven to be superior to conventional echocardiographic techniques. Although the overall structures are much better displayed by three-dimensional visualization methods, it is sometimes difficult to comprehend the orientation of the scene, since anatomical landmarks like the aortic outflow tract may be hidden by other structures. Also, such anatomical landmarks often are only partly contained in the acquired data set so that they are clearly visible in a few slices only, making them difficult to find in a three-dimensional visualization. The knowledge of the absolute orientation is of essential value for the surgeon to mentally transfer the preoperatively acquired data to the intraoperative situs. Therefore, it is desirable to have additional hints for orientation in the three-dimensional scene. We present methods that enable better and easier orientation and therefore improve the usability of three-dimensional echocardiography.
Combined photoacoustic and ultrasound biomicroscopy.
Harrison, Tyler; Ranasinghesagara, Janaka C; Lu, Huihong; Mathewson, Kory; Walsh, Andrew; Zemp, Roger J
2009-11-23
We report on the development of an imaging system capable of combined ultrasound and photoacoustic imaging based on a fast-scanning single-element 25-MHz ultrasound transducer and a unique light-delivery system. The system is capable of 20 ultrasound frames per second and slower photoacoustic frame rates limited by laser pulse-repetition rates. Laser and ultrasound pulses are interlaced for co-registration of photoacoustic and ultrasound images. In vivo imaging of a human finger permits ultrasonic visualization of vessel structures and speckle changes indicative of blood flow, while overlaid photoacoustic images highlight some small vessels that are not clear from the ultrasound scan. Photoacoustic images provide optical absorption contrast co-registered in the structural and blood-flow context of ultrasound with high-spatial resolution and may prove important for clinical diagnostics and basic science of the microvasculature.
Radiation hardness of three-dimensional polycrystalline diamond detectors
Lagomarsino, Stefano Sciortino, Silvio; Bellini, Marco; Corsi, Chiara; Cindro, Vladimir; Kanxheri, Keida; Servoli, Leonello; Morozzi, Arianna; Passeri, Daniele; Schmidt, Christian J.
2015-05-11
The three-dimensional concept in particle detection is based on the fabrication of columnar electrodes perpendicular to the surface of a solid state radiation sensor. It permits to improve the radiation resistance characteristics of a material by lowering the necessary bias voltage and shortening the charge carrier path inside the material. If applied to a long-recognized exceptionally radiation-hard material like diamond, this concept promises to pave the way to the realization of detectors of unprecedented performances. We fabricated conventional and three-dimensional polycrystalline diamond detectors, and tested them before and after neutron damage up to 1.2 ×10{sup 16 }cm{sup −2}, 1 MeV-equivalent neutron fluence. We found that the signal collected by the three-dimensional detectors is up to three times higher than that of the conventional planar ones, at the highest neutron damage ever experimented.
Ray tracing a three dimensional scene using a grid
Wald, Ingo; Ize, Santiago; Parker, Steven G; Knoll, Aaron
2013-02-26
Ray tracing a three-dimensional scene using a grid. One example embodiment is a method for ray tracing a three-dimensional scene using a grid. In this example method, the three-dimensional scene is made up of objects that are spatially partitioned into a plurality of cells that make up the grid. The method includes a first act of computing a bounding frustum of a packet of rays, and a second act of traversing the grid slice by slice along a major traversal axis. Each slice traversal includes a first act of determining one or more cells in the slice that are overlapped by the frustum and a second act of testing the rays in the packet for intersection with any objects at least partially bounded by the one or more cells overlapped by the frustum.
Shape memory polymers: three-dimensional isotropic modeling
NASA Astrophysics Data System (ADS)
Balogun, Olaniyi; Mo, Changki
2014-04-01
This paper presents a comprehensive three-dimensional isotropic numerical simulation for a thermo-mechanical constitutive model of shape memory polymers (SMPs). In order to predict the thermo-mechanical behavior of SMPs, a one-dimensional rheological thermo-mechanical constitutive model is adopted, translated into a three-dimensional form and a time discrete form of the three-dimensional model is then presented. Numerical simulation of this model was developed using the UMAT subroutine capabilities of the finite element software ABAQUS. Evolution of the analysis was conducted by making use of the backward difference scheme, which was applied to all quantities within the model, including the material properties. A comparison of the numerical simulation results was carried out with the available experimental data. Numerical simulation results clearly exhibit the thermo-mechanical properties of the material which include shape fixity, shape recovery, and recovery stress. Finally, a prediction for the transverse and shear directions of the material is presented.
Three-dimensional diamagnetic particle deflection in ferrofluid microchannel flows.
Liang, Litao; Zhu, Junjie; Xuan, Xiangchun
2011-09-01
Magnetic field-induced particle manipulation is a promising technique for biomicrofluidics applications. It is simple, cheap, and also free of fluid heating issues that accompany other common electric, acoustic, and optical methods. This work presents a fundamental study of diamagnetic particle motion in ferrofluid flows through a rectangular microchannel with a nearby permanent magnet. Due to their negligible magnetization relative to the ferrofluid, diamagnetic particles experience negative magnetophoresis and are repelled away from the magnet. The result is a three-dimensionally focused particle stream flowing near the bottom outer corner of the microchannel that is the farthest to the center of the magnet and hence has the smallest magnetic field. The effects of the particle's relative position to the magnet, particle size, ferrofluid flow rate, and concentration on this three-dimensional diamagnetic particle deflection are systematically studied. The obtained experimental results agree quantitatively with the predictions of a three-dimensional analytical model.
Antimicrobial-finished textile three-dimensional structures.
Heide, M; Möhring, U; Hänsel, R; Stoll, M; Wollina, U; Heinig, B
2006-01-01
This paper describes the possibilities of antimicrobial finishing of three-dimensional spacer fabrics and its applications, and gives information about the different effects. A research project of the Textilforschungsinstitut Thüringen-Vogtland Greiz is presented in which medical shoe insoles, based on specially manufactured three-dimensional spacer fabrics, made of permanently effective antimicrobial yarns were used for interesting and functional textile products. Furthermore, work of the research institute Forschungsinstitut für Leder und Kunststoffbahnen Freiberg is presented which describes the silver-coating process and application of textile materials using antimicrobial substances. The chemical and mechanical stability is investigated, and proof of the effectiveness is supplied. The results show that in the three-dimensional spacer fabrics both - antimicrobial yarn materials and thin silver films with antimicrobial substances - can achieve an antimicrobial effect, even in low quantities.
Time of Closest Approach in Three-Dimensional Airspace
NASA Technical Reports Server (NTRS)
Munoz, Cesar A.; Narkawicz, Anthony J.
2010-01-01
In air traffic management, the aircraft separation requirement is defined by a minimum horizontal distance and a minimum vertical distance that the aircraft have to maintain. Since this requirement defines a cylinder around each aircraft rather than a sphere, the three-dimensional Euclidean distance does not provide an appropriate basis for the definition of time of closest approach. For instance, conflicting aircraft are not necessarily in loss of separation at the time of closest three-dimensional Euclidean distance. This paper proposes a definition of time of closest approach that characterizes conflicts in a three-dimensional airspace. The proposed time is defined as the time that minimizes a distance metric called cylindrical norm. An algorithm that computes the time of closest approach between two aircraft is provided and the formal verification of its main properties is reported.
Coupled particle dispersion by three-dimensional vortex structures
Troutt, T.R.; Chung, J.N.; Crowe, C.T.
1996-12-31
The primary objective of this research program is to obtain understanding concerning the role of three-dimensional vortex structures in the dispersion of particles and droplets in free shear flows. This research program builds on previous studies which focused on the nature of particle dispersion in large scale quasi two-dimensional vortex structures. This investigation employs time dependent experimental and numerical techniques to provide information concerning the particulate dispersion produced by three dimensional vortex structures in free shear layers. The free shear flows investigated include modified plane mixing layers, and modified plane wakes. The modifications to these flows involve slight perturbations to the initiation boundary conditions such that three-dimensional vortex structures are rapidly generated by the experimental and numerical flow fields. Recent results support the importance of these vortex structures in the particle dispersion process.
Three-dimensional numerical simulations of falling liquid films
NASA Astrophysics Data System (ADS)
Pain, Christopher; Xie, Zhihua; Pavlidis, Dimitrios; Salinas, Pablo; Matar, Omar
2016-11-01
Falling liquid films down an inclined or vertical surface have rich wave dynamics, often occurring in many industrial applications, such as condensers, evaporators and chemical reactors. There are some numerical studies for falling liquid films, however most of them have focused on two-dimensional falling films or three-dimensional falling films in a periodic domain. The objective of this study is to investigate flow dynamics of fully developed three-dimensional falling films using the Navier-Stokes equations coupled with interface capturing approach. An adaptive unstructured mesh modelling framework is employed here to study this problem, which can modify and adapt unstructured meshes to better represent the underlying physics of multiphase problems and reduce computational effort without sacrificing accuracy. Numerical examples of two-dimensional and three-dimensional falling films in a long domain with different flow conditions are presented and discussed. EPSRC UK Programme Grant MEMPHIS (EP/K003976/1).
Hydrofocusing Bioreactor for Three-Dimensional Cell Culture
NASA Technical Reports Server (NTRS)
Gonda, Steve R.; Spaulding, Glenn F.; Tsao, Yow-Min D.; Flechsig, Scott; Jones, Leslie; Soehnge, Holly
2003-01-01
The hydrodynamic focusing bioreactor (HFB) is a bioreactor system designed for three-dimensional cell culture and tissue-engineering investigations on orbiting spacecraft and in laboratories on Earth. The HFB offers a unique hydrofocusing capability that enables the creation of a low-shear culture environment simultaneously with the "herding" of suspended cells, tissue assemblies, and air bubbles. Under development for use in the Biotechnology Facility on the International Space Station, the HFB has successfully grown large three-dimensional, tissuelike assemblies from anchorage-dependent cells and grown suspension hybridoma cells to high densities. The HFB, based on the principle of hydrodynamic focusing, provides the capability to control the movement of air bubbles and removes them from the bioreactor without degrading the low-shear culture environment or the suspended three-dimensional tissue assemblies. The HFB also provides unparalleled control over the locations of cells and tissues within its bioreactor vessel during operation and sampling.
Three-dimensional analysis of partially open butterfly valve flows
Huang, C.; Kim, R.H.
1996-09-01
A numerical simulation of butterfly valve flows is a useful technique to investigate the physical phenomena of the flow field. A three-dimensional numerical analysis was carried out on incompressible fluid flows in a butterfly valve by using FLUENT, which solves difference equations. Characteristics of the butterfly valve flows at different valve disk angles with a uniform incoming velocity were investigated. Comparisons of FLUENT results with other results, i.e., experimental results, were made to determine the accuracy of the employed method. Results of the three-dimensional analysis may be useful in the valve design.
Three-dimensional ultrasonography in hepatobiliary and pancreatic diseases.
Sackmann, M; Pauletzki, J; Zwiebel, F M; Holl, J
1994-06-01
Three-dimensional reconstruction of ultrasonographic images was used to visualize hepatobiliary and pancreatic lesions and stones, and to measure gallbladder emptying. The initial experience shows that these reconstructions may be of some help in the identification of the extension of tumors and the invasion into surrounding tissues. Stones and stone fragments in the pancreas and in the gallbladder as well as the wall of the gallbladder were visualized well. If further studies will reveal a benefit for the patient, three-dimensional ultrasonography may be added to the noninvasive methods used in the diagnosis of several hepatobiliary and pancreatic diseases.
Three-Dimensional Prints with Pinned Cylindrical Lens Arrays
NASA Astrophysics Data System (ADS)
Yasuda, Shin; Shimizu, Keishi
2013-09-01
An application of pinned cylindrical lens arrays (CLAs) reported in Opt. Rev. 19 (2012) 287 to three-dimensional prints is presented for the first time. This lens fabrication method features the easy control of the pitch and radius of curvature of the lens arrays by taking advantage of the pinning effect that the partition walls created on a polymeric substrate by scratching with a cutter blade prevent the ultraviolet curable polymer dispensed between the walls from spreading. It is demonstrated in this paper that a three-dimensional print was realized successfully with the pinned CLA fabricated with our method.
Bootstrapping Critical Ising Model on Three Dimensional Real Projective Space.
Nakayama, Yu
2016-04-08
Given conformal data on a flat Euclidean space, we use crosscap conformal bootstrap equations to numerically solve the Lee-Yang model as well as the critical Ising model on a three dimensional real projective space. We check the rapid convergence of our bootstrap program in two dimensions from the exact solutions available. Based on the comparison, we estimate that our systematic error on the numerically solved one-point functions of the critical Ising model on a three dimensional real projective space is less than 1%. Our method opens up a novel way to solve conformal field theories on nontrivial geometries.
Simulation of Three-Dimensional Positive Photoresist Images
NASA Astrophysics Data System (ADS)
Barouch, E.; Bradie, B.; Babu, S. V.
1989-12-01
The least-action dissolution algorithm (LEAD) is applied to simulate three-dimensional positive photoresist images on reflective substrates. This algorithm avoids the ambiguities of the string algorithm and its modifications by utilizing the local validity of the eikonal description of the underlying diffusion equation to describe developer penetration with a moving boundary. The electric field and the concentration of the photoactive compound (PAC) within the photoresist film in the presence of standing waves in three dimensions are obtained from the numerically efficient WKB procedure proposed recently. The PAC concentration profile is combined with the LEAD algorithm to simulate a three dimensional one micron diameter contact hole in a single layer resist.
Structure of turbulence in three-dimensional boundary layers
NASA Technical Reports Server (NTRS)
Subramanian, Chelakara S.
1993-01-01
This report provides an overview of the three dimensional turbulent boundary layer concepts and of the currently available experimental information for their turbulence modeling. It is found that more reliable turbulence data, especially of the Reynolds stress transport terms, is needed to improve the existing modeling capabilities. An experiment is proposed to study the three dimensional boundary layer formed by a 'sink flow' in a fully developed two dimensional turbulent boundary layer. Also, the mean and turbulence field measurement procedure using a three component laser Doppler velocimeter is described.
Three Dimensional Imaging with Multiple Wavelength Speckle Interferometry
Bernacki, Bruce E.; Cannon, Bret D.; Schiffern, John T.; Mendoza, Albert
2014-05-28
We present the design, modeling, construction, and results of a three-dimensional imager based upon multiple-wavelength speckle interferometry. A surface under test is illuminated with tunable laser light in a Michelson interferometer configuration while a speckled image is acquired at each laser frequency step. The resulting hypercube is Fourier transformed in the frequency dimension and the beat frequencies that result map the relative offsets of surface features. Synthetic wavelengths resulting from the laser tuning can probe features ranging from 18 microns to hundreds of millimeters. Three dimensional images will be presented along with modeling results.
Three-dimensional external flow computations using prismatic grid
NASA Astrophysics Data System (ADS)
Nakahashi, Kazuhiro
1992-12-01
A new approach to compute external viscous flows around three dimensional configurations is proposed. A prismatic grid is used where the three dimensional surface is covered by triangles similar to the unstructured grid. The direction away from the body surface is structured so as to achieve efficient and accurate computations for high Reynolds number viscous flows. The prismatic grid is generated by a newly developed marching-type procedure in which grid spacings are controlled by a variational method. The capability of the method is demonstrated by applying it to a viscous flow computation around a complete aircraft configuration.
A system of three-dimensional complex variables
NASA Technical Reports Server (NTRS)
Martin, E. Dale
1986-01-01
Some results of a new theory of multidimensional complex variables are reported, including analytic functions of a three-dimensional (3-D) complex variable. Three-dimensional complex numbers are defined, including vector properties and rules of multiplication. The necessary conditions for a function of a 3-D variable to be analytic are given and shown to be analogous to the 2-D Cauchy-Riemann equations. A simple example also demonstrates the analogy between the newly defined 3-D complex velocity and 3-D complex potential and the corresponding ordinary complex velocity and complex potential in two dimensions.
Three-dimensional standing waves in a microwave oven
NASA Astrophysics Data System (ADS)
Kamol, S.; Limsuwan, P.; Onreabroy, W.
2010-05-01
A microwave oven operating at a frequency of 2.45 GHz was designed for demonstrating three-dimensional standing waves. The three-dimensional standing wave patterns formed on cobalt chloride paper placed at the center of the oven chamber were examined. The images on the cobalt chloride paper corresponding to antinodes of the standing waves were recorded by a digital camera after turning on the microwave oven. The results show that the numbers of antinodes of the standing waves in each plane agree with those of the theoretical calculation of the electric field distribution in the oven chamber.
Novel multipole Wien filter as three-dimensional spin manipulator
Yasue, T. Suzuki, M.; Koshikawa, T.; Tsuno, K.; Goto, S.; Arai, Y.
2014-04-15
Spin polarized electron beam is often used in material characterizations which relates to magnetism as well as in the high energy particle physics. The manipulation of the spin polarization toward the arbitrary direction is indispensable in such studies. In the present work, a novel multipole Wien filter is proposed as the three-dimensional spin manipulator, and a prototype 8-pole Wien filter is developed. It is applied to spin polarized low energy electron microscopy, and the variation of the magnetic contrast with managing the spin polarization is evaluated. It is confirmed that the novel multipole Wien filter can manipulate the spin polarization three-dimensionally.
Three-dimensional structural analysis using interactive graphics
NASA Technical Reports Server (NTRS)
Biffle, J.; Sumlin, H. A.
1975-01-01
The application of computer interactive graphics to three-dimensional structural analysis was described, with emphasis on the following aspects: (1) structural analysis, and (2) generation and checking of input data and examination of the large volume of output data (stresses, displacements, velocities, accelerations). Handling of three-dimensional input processing with a special MESH3D computer program was explained. Similarly, a special code PLTZ may be used to perform all the needed tasks for output processing from a finite element code. Examples were illustrated.
A class of auxetic three-dimensional lattices
NASA Astrophysics Data System (ADS)
Cabras, Luigi; Brun, Michele
2016-06-01
We propose a class of auxetic three-dimensional lattice structures. The elastic microstructure can be designed to have an omnidirectional Poisson's ratio arbitrarily close to the stability limit of -1. The cubic behaviour of the periodic system has been fully characterized; the minimum and maximum Poisson's ratio and the associated principal directions are given as a function of the microstructural parameters. The initial microstructure is then modified into a body-centred cubic system that can achieve Poisson's ratio lower than -1 and that can also behave as an isotropic three-dimensional auxetic structure.
Microperiodic structures: direct writing of three-dimensional webs.
Gratson, Gregory M; Xu, Mingjie; Lewis, Jennifer A
2004-03-25
Applications are emerging that require the creation of fine-scale structures in three dimensions--examples include scaffolds for tissue engineering, micro-fluidic devices and photonic materials that control light propagation over a range of frequencies. But writing methods such as dip-pen nanolithography and ink-jet printing are either confined to two dimensions or beset by wetting and spreading problems. Here we use concentrated polyelectrolyte inks to write three-dimensional microperiodic structures directly without using masks. Our technique enables us to write arbitrary three-dimensional patterns whose features are nearly two orders of magnitude smaller than those attained with other multilayer printing techniques.
Three-dimensional boron particle loaded thermal neutron detector
Nikolic, Rebecca J.; Conway, Adam M.; Graff, Robert T.; Kuntz, Joshua D.; Reinhardt, Catherine; Voss, Lars F.; Cheung, Chin Li; Heineck, Daniel
2014-09-09
Three-dimensional boron particle loaded thermal neutron detectors utilize neutron sensitive conversion materials in the form of nano-powders and micro-sized particles, as opposed to thin films, suspensions, paraffin, etc. More specifically, methods to infiltrate, intersperse and embed the neutron nano-powders to form two-dimensional and/or three-dimensional charge sensitive platforms are specified. The use of nano-powders enables conformal contact with the entire charge-collecting structure regardless of its shape or configuration.
Radiative Instabilities in Three-Dimensional Astrophysical Masers
NASA Technical Reports Server (NTRS)
Scappaticci, Gerardo A.; Watson, William D.
1995-01-01
Inherent instabilities in the radiative transfer for astrophysical masers have been recognized and calculated in the linear maser idealization in our previous investigations. The same instabilities are now shown to occur in the more realistic, three-dimensional geometries. Fluctuations in the emergent flux result and may be related to the observed fluctuations in the radiative flux from the 1665 MHz OH masers that have been reported to occur on timescales as short as 1000 s. The time-dependent differential equations of radiative transfer are solved numerically for three-dimensional astrophysical masers. Computations are performed for spherical and elongated (rectangular parallelepiped) geometries.
Binary Colloidal Alloy Test-5: Three-Dimensional Melt
NASA Technical Reports Server (NTRS)
Yodh, Arjun G.
2008-01-01
Binary Colloidal Alloy Test - 5: Three-Dimensional Melt (BCAT-5-3DMelt) photographs initially randomized colloidal samples in microgravity to determine their resulting structure over time. BCAT-5-3D-Melt will allow the scientists to capture the kinetics (evolution) of their samples, as well as the final equilibrium state of each sample. BCAT-5-3D-Melt will look at the mechanisms of melting using three-dimensional temperature sensitive colloidal crystals. Results will help scientists develop fundamental physics concepts previously shadowed by the effects of gravity.
Applications of three-dimensionally scanned models in orthodontics.
Cha, B K; Choi, J I; Jost-Brinkmann, P G; Jeong, Y M
2007-01-01
The purpose of this study was to investigate clinical applications of the three-dimensional reverse engineering technologies for the analysis of orthodontic models. The measuring accuracy and the process of the 3D model scanning technique were evaluated with respect to linear, surface and volumetric parameters. Orthodontically induced dentoalveolar changes, which have been traditionally evaluated by cephalometric analysis, were assessed by the registration function of Rapidform 2002, a 3D-reverse modeling software in scanned maxillary casts. Three-dimensional digital models are valuable alternatives to conventional casts for model analysis and also yield information which could previously be gathered only by cephalometric superimposition.
NASA Astrophysics Data System (ADS)
Fenton, Flavio H.; Evans, Steven J.; Hastings, Harold M.; Cherry, Elizabeth M.
2006-03-01
Presentation and analysis of large three-dimensional data sets is in general hard to do using only two-dimensional figures and plots. In this talk, we will demonstrate techniques for illustrating static and dynamic three-dimensional objects and data using Virtual Reality Modeling Language (VRML) as well as Java. The advantage of these two languages is that they are platform-independent, which allows for easy sharing of data and visualizations. In addition, manipulation of data is relatively easy as rotation, translation and zooming can be done in real- time for static objects as well as for data and objects that vary and deform in time. Examples of fully three-dimensional movies will be shown, including dendritic growth and propagation of electrical waves in cardiac tissue. In addition, we will show how to include VRML and Java viewers in PowerPoint for easy presentation of results in classes and seminars.
Development of Three-Dimensional Completion of Complex Objects
ERIC Educational Resources Information Center
Soska, Kasey C.; Johnson, Scott P.
2013-01-01
Three-dimensional (3D) object completion, the ability to perceive the backs of objects seen from a single viewpoint, emerges at around 6 months of age. Yet, only relatively simple 3D objects have been used in assessing its development. This study examined infants' 3D object completion when presented with more complex stimuli. Infants…
Algebraic Ricci solitons of three-dimensional Lorentzian Lie groups
NASA Astrophysics Data System (ADS)
Batat, W.; Onda, K.
2017-04-01
We study algebraic Ricci solitons of three-dimensional Lorentzian Lie groups. All algebraic Ricci solitons that we obtain are solvsolitons. In particular, we obtain new solitons on G2, G5, and G6, and we prove that, contrary to the Riemannian case, Lorentzian Ricci solitons need not be algebraic Ricci solitons.
Three-Dimensional Extension of a Digital Library Service System
ERIC Educational Resources Information Center
Xiao, Long
2010-01-01
Purpose: The paper aims to provide an overall methodology and case study for the innovation and extension of a digital library, especially the service system. Design/methodology/approach: Based on the three-dimensional structure theory of the information service industry, this paper combines a comprehensive analysis with the practical experiences…
Three-dimensional cell to tissue development process
NASA Technical Reports Server (NTRS)
Goodwin, Thomas J. (Inventor); Parker, Clayton R. (Inventor)
2008-01-01
An improved three-dimensional cell to tissue development process using a specific time varying electromagnetic force, pulsed, square wave, with minimum fluid shear stress, freedom for 3-dimensional spatial orientation of the suspended particles and localization of particles with differing or similar sedimentation properties in a similar spatial region.
Polyimide Aerogels with Three-Dimensional Cross-Linked Structure
NASA Technical Reports Server (NTRS)
Meador, Mary Ann B. (Inventor)
2016-01-01
A method for creating a three dimensional cross-linked polyimide structure includes dissolving a diamine, a dianhydride, and a triamine in a solvent, imidizing a polyamic acid gel by heating the gel, extracting the gel in a second solvent, supercritically drying the gel, and removing the solvent to create a polyimide aerogel.
Three-dimensional acousto-optic spectrum analysis
NASA Technical Reports Server (NTRS)
Ansari, Homayoon; Metscher, Brian; Lesh, James R.
1990-01-01
A three-dimensional acoustooptic spectrum analyzer with subhertz resolution is demonstrated experimentally. The first and second dimensions are the two spatial dimensions of the output detector array, and the third dimension is time as sampled by the detector array frame rate. A superfine resolution of 0.12 Hz has been achieved.
Interactive Multimedia and Concrete Three-Dimensional Modelling.
ERIC Educational Resources Information Center
Baxter, J. H.; Preece, Peter F. W.
1999-01-01
Compares a multimedia package for teaching about the phases of the moon to grade 8 (12-year-old) students with a conventional three-dimensional modeling approach. Results show both methods were equally effective in terms of student learning, for male and female students, and prior computer experience was not a factor in multimedia use. (Author/LRW)
Speed and pressure recording in three-dimensional flow
NASA Technical Reports Server (NTRS)
Krisam, F
1932-01-01
Van der Megge Zijnen's spherical Pitot tube with its 5 test holes insures a simultaneous record of static pressure and magnitude and direction of velocity in three-dimensional flow. The report treats the method as well as the range of application of this Pitot in the light of modern knowledge on flow around spheres.
Three-Dimensional Interactive Design Using Bezier Curves and Surfaces.
ERIC Educational Resources Information Center
Khonsari, M. M.; Horn, D.
1987-01-01
Offers a method for interactive design of objects on a computer. Outlines a method which allows the designer to interact with orthogonal views to construct a three dimensional model of an arbitrary shape. Presents an algorithm based on the Bezier curves to efficiently create smooth curves and surfaces. (CW)
Three-Dimensional Space to Assess Cloud Interoperability
2013-03-01
major cloud providers, OpenStack and OpeNebula, to demonstrate the usage of the three-dimensional space and its benefits . We start this chapter with a...documentation:rel4.0:external_auth. [68] X. Gao, P. Shah, A. Yoga , A. Kodgire and X. Ni. Cloud storage survey [Online]. Available: http
Three-dimensional measurements of fatigue crack closure
NASA Technical Reports Server (NTRS)
Ray, S. K.; Grandt, A. F., Jr.
1984-01-01
Fatigue crack growth and retardation experiments conducted in polycarbonate test specimen are described. The transparent test material allows optical interferometry measurements of the fatigue crack opening (and closing) profiles. Crack surface displacements are obtained through the specimen thickness and three dimensional aspects of fatigue crack closure are discussed.
Numerical investigations in three-dimensional internal flows
NASA Technical Reports Server (NTRS)
Rose, William C.
1990-01-01
The flow in the transonic test facility was investigated using the three dimensional computational fluid dynamics techniques. The application of the full Navier-Stokes three dimensional code to the flow qualities in the contraction section of transonic wind tunnel is discussed. Initially, two dimensional solutions indicated the possibility for large secondary flow to exist as a result of the asymmetries involved in the contraction section as it is constructed. The results of a full three dimensional solution indicate that only minor pressure variations actually occur in the contraction section within any given cross flow plane. Further analysis of the three dimensional solution indicated that these slight lateral pressure gradients lead to negligible secondary flows, except within a small region in the corners within the boundary layer. On the basis of present solution, it would not be expected that any flow asymmetries and/or secondary flow present within contraction section are associated with the methods by which the contraction is implemented in its present configuration.
Three-dimensional shallow water system: A relaxation approach
NASA Astrophysics Data System (ADS)
Liu, Xin; Mohammadian, Abdolmajid; Infante Sedano, Julio Ángel; Kurganov, Alexander
2017-03-01
We study a three-dimensional shallow water system, which is obtained from the three-dimensional Navier-Stokes equations after Reynolds averaging and under the simplifying hydrostatic pressure assumption. Since the three-dimensional shallow water system is generically not hyperbolic, it cannot be numerically solved using hyperbolic shock capturing schemes. At the same time, existing simple finite-difference and finite-volume methods may fail in simulations of unsteady flows with sharp gradients, such as dam-break and flood flows. To overcome this limitation, we propose a novel numerical method, which is based on a relaxation approach utilized to "hyperbolize" the three-dimensional shallow water system. The extended relaxation system is hyperbolic and we develop a second-order semi-discrete central-upwind scheme for it. The proposed numerical method can preserve "lake at rest" steady states and positivity of water depth over irregular bottom topography. The accuracy, stability and robustness of the developed numerical method is verified on five numerical experiments.
Assembly of Viral Hydrogels for Three-Dimensional Conducting Nanocomposites
Chen, Po-Yen; Hyder, Md Nasim; Mackanic, David; Courchesne, Noémie-Manuelle Dorval; Qi, Jifa
2014-01-01
M13 bacteriophages act as versatile scaffolds capable of organizing single-walled carbon nanotubes and fabricating three-dimensional conducting nanocomposites. The morphological, electrical, and electrochemical properties of the nanocomposites are presented, as well as its ability to disperse and utilize single-walled carbon nanotubes effectively. PMID:24782428
Computer Generated Holography as a Three-Dimensional Display Medium
1990-12-01
series of two dimensional images are reflected on an object screen resulting in an autostereoscopic , or true three dimensional, images. The advantages of...an attractive target to optimize. Jack Ritter has suggested a fast approximation to 3D Euclidean distance calculations (10:432). His methid uses no
Potential Flows From Three-Dimensional Complex Variables
NASA Technical Reports Server (NTRS)
Martin, E. Dale; Kelly, Patrick H.; Panton, Ronald L.
1992-01-01
Report presents investigation of several functions of three-dimensional complex variable, with emphasis on potential-flow fields computed from these functions. Part of continuing research on generalization of well-established two-dimensional complex analysis to three and more dimensions.
View Factor Calculation for Three-Dimensional Geometries.
1989-06-20
Version 00 MCVIEW calculates the radiation geometric view factor between surfaces for three dimensional geometries with and without interposed third surface obstructions. It was developed to calculate view factors for input data to heat transfer analysis programs such as SCA-03/TRUMP, SCA-01/HEATING-5 and PSR-199/HEATING-6.
Two-Dimensional Chirality in Three-Dimensional Chemistry.
ERIC Educational Resources Information Center
Wintner, Claude E.
1983-01-01
The concept of two-dimensional chirality is used to enhance students' understanding of three-dimensional stereochemistry. This chirality is used as a key to teaching/understanding such concepts as enaniotropism, diastereotopism, pseudoasymmetry, retention/inversion of configuration, and stereochemical results of addition to double bonds. (JN)
Three dimensional boundary layers on submarine conning towers and rudders
NASA Astrophysics Data System (ADS)
Gleyzes, C.
1988-01-01
Solutions for the definition of grids adapted to the calculation of three-dimensional boundary layers on submarine conning towers and on submarine rudders and fins are described. The particular geometry of such bodies (oblique shaped hull, curved fins) required special adaptations. The grids were verified on examples from a test basin.
Three-dimensional evolution of early solar nebula
NASA Technical Reports Server (NTRS)
Boss, Alan P.
1991-01-01
The progress is reported toward the goal of a complete theory of solar nebula formation, with an emphasis on three spatial dimension models of solar nebular formation and evolution. The following subject areas are covered: (1) initial conditions for protostellar collapse; (2) single versus binary star formation; (3) angular momentum transport mechanisms; (4) three dimensional solar nebula models; and (5) implications for planetary formation.
Constructing Mental Representations of Complex Three-Dimensional Objects.
ERIC Educational Resources Information Center
Aust, Ronald
This exploratory study investigated whether there are differences between males and females in the strategies used to construct mental representations from three-dimensional objects in a dimensional travel display. A Silicon Graphics IRIS computer was used to create the travel displays and mathematical models were created for each of the objects…
A three dimensional calculation of elastic equilibrium for composite materials
NASA Technical Reports Server (NTRS)
Lustman, Liviu R.; Rose, Milton E.
1986-01-01
A compact scheme is applied to three-dimensional elasticity problems for composite materials, involving simple geometries. The mathematical aspects of this approach are discussed, in particular the iteration method. A vector processor code implementing the compact scheme is presented, and several numerical experiments are summarized.
Three-dimensional AOTV flowfields in chemical nonequilibrium
NASA Technical Reports Server (NTRS)
Gnoffo, P. A.; Mccandless, R. S.
1986-01-01
A technique for upwind differencing of the three-dimensional species continuity equations is presented which permits computation of steady flows in chemical equilibrium and nonequilibrium. The capabilities and shortcomings of the present approach for equilibrium and nonequilibrium flows is discussed. Modifications now being investigated to improve computational time are outlined.
Modern cosmology and the origin of our three dimensionality.
Woodbury, M A; Woodbury, M F
1998-01-01
We are three dimensional egocentric beings existing within a specific space/time continuum and dimensionality which we assume wrongly is the same for all times and places throughout the entire universe. Physicists name Omnipoint the origin of the universe at Dimension zero, which exploded as a Big Bang of energy proceeding at enormous speed along one dimension which eventually curled up into matter: particles, atoms, molecules and Galaxies which exist in two dimensional space. Finally from matter spread throughout the cosmos evolved life generating eventually the DNA molecules which control the construction of brains complex enough to construct our three dimensional Body Representation from which is extrapolated what we perceive as a 3-D universe. The whole interconnected structures which conjure up our three dimensionality are as fragile as Humpty Dumpty, capable of breaking apart with terrifying effects for the individual patient during a psychotic panic, revealing our three dimensionality to be but "maya", an illusion, which we psychiatrists work at putting back together.
THREE-DIMENSIONAL NAPL FATE AND TRANSPORT MODEL
We have added several new and significant capabilities to UTCHEM to make it into a general-purpose NAPL simulator. The simulator is now capable of modeling transient and steady-state three-dimensional flow and mass transport in the groundwater (saturated) and vadose (unsaturated...
A Three-Dimensional Haptic Matrix Test of Nonverbal Reasoning
ERIC Educational Resources Information Center
Miller, Joseph C.; Skillman, Gemma D.; Benedetto, Joanne M.; Holtz, Ann M.; Nassif, Carrie L.; Weber, Anh D.
2007-01-01
Three-dimensional haptic matrices were pilot-tested as a nonvisual measure of cognitive ability. The results indicated that they correlated with convergent measures, with emphasis on spatial processing and that the participants who described items "visually" completed them more quickly and accurately and tended to have become visually…
Three-Dimensional Printing Using a Photoinitiated Polymer
ERIC Educational Resources Information Center
Muskin, Joseph; Ragusa, Matthew; Gelsthorpe, Thomas
2010-01-01
Printers capable of producing three-dimensional objects are becoming more common. Most of these printers are impractical for use in the chemistry classroom because of the expense incurred in fabricating a print head that must be controlled in three dimensions. We propose a simpler solution to this problem that allows the emerging technology of…
Heat engine in the three-dimensional spacetime
NASA Astrophysics Data System (ADS)
Mo, Jie-Xiong; Liang, Feng; Li, Gu-Qiang
2017-03-01
We define a kind of heat engine via three-dimensional charged BTZ black holes. This case is quite subtle and needs to be more careful. The heat flow along the isochores does not equal to zero since the specific heat C V ≠ 0 and this point completely differs from the cases discussed before whose isochores and adiabats are identical. So one cannot simply apply the paradigm in the former literatures. However, if one introduces a new thermodynamic parameter associated with the renormalization length scale, the above problem can be solved. We obtain the analytical efficiency expression of the three-dimensional charged BTZ black hole heat engine for two different schemes. Moreover, we double check with the exact formula. Our result presents the first specific example for the sound correctness of the exact efficiency formula. We argue that the three-dimensional charged BTZ black hole can be viewed as a toy model for further investigation of holographic heat engine. Furthermore, we compare our result with that of the Carnot cycle and extend the former result to three-dimensional spacetime. In this sense, the result in this paper would be complementary to those obtained in four-dimensional spacetime or ever higher. Last but not the least, the heat engine efficiency discussed in this paper may serve as a criterion to discriminate the two thermodynamic approaches introduced in ref. [29] and our result seems to support the approach which introduces a new thermodynamic parameter R = r 0 .
Development of Three-Dimensional Object Completion in Infancy
ERIC Educational Resources Information Center
Soska, Kasey C.; Johnson, Scott P.
2008-01-01
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[degrees], providing only a limited view. Two displays, rotating 360[degrees], were then shown: a complete, solid volume and an incomplete, hollow form composed only of the sides…
Three dimensional flow measurements in a turbine scroll
NASA Technical Reports Server (NTRS)
Tabakoff, W.; Vittal, B. V. R.; Wood, B.
1982-01-01
A study was conducted to determine experimentally the flow behavior in combined scroll nozzle assembly of a radial inflow turbine. Hot film anemometry technique was used to measure the three dimensional flow velocity in the scroll. The through flow and secondary flow velocity components are measured at various points in three scroll sections.
High three dimensional thermoelectric performance from low dimensional bands
Singh, David J; Chen, Xin; Parker, David S
2013-01-01
Reduced dimensionality has long been regarded as an important strategy for increasing thermoelectric performance, for example in superlattices and other engineered structures. Here we point out and illustrate by examples that three dimensional bulk materials can be made to behave as if they were two dimensional from the point of view of thermoelectric performance. Implications for the discovery of new practical thermoelectrics are discussed.
A Novel Three-Dimensional Tool for Teaching Human Neuroanatomy
ERIC Educational Resources Information Center
Estevez, Maureen E.; Lindgren, Kristen A.; Bergethon, Peter R.
2010-01-01
Three-dimensional (3D) visualization of neuroanatomy can be challenging for medical students. This knowledge is essential in order for students to correlate cross-sectional neuroanatomy and whole brain specimens within neuroscience curricula and to interpret clinical and radiological information as clinicians or researchers. This study implemented…
Quantum field between moving mirrors: A three dimensional example
NASA Technical Reports Server (NTRS)
Hacyan, S.; Jauregui, Roco; Villarreal, Carlos
1995-01-01
The scalar quantum field uniformly moving plates in three dimensional space is studied. Field equations for Dirichlet boundary conditions are solved exactly. Comparison of the resulting wavefunctions with their instantaneous static counterpart is performed via Bogolubov coefficients. Unlike the one dimensional problem, 'particle' creation as well as squeezing may occur. The time dependent Casimir energy is also evaluated.
Three-Dimensional Printing: A Journey in Visualization
ERIC Educational Resources Information Center
Poetzel, Adam; Muskin, Joseph; Munroe, Anne; Russell, Craig
2012-01-01
Imagine high school students glued to computer screens--not playing video games but applying their mathematical knowledge of functions to the design of three-dimensional sculptures. Imagine these students engaging in rich discourse as they transform functions of their choosing to design unique creations. Now, imagine these students using…
THREE-DIMENSIONAL TEACHING AIDS FOR TRADE AND INDUSTRIAL INSTRUCTION.
ERIC Educational Resources Information Center
ROSENGREN, HAROLD J.
THREE-DIMENSIONAL MODELS ARE USED WITH GREAT EFFECTIVENESS AS TEACHING AIDS. CONCEPTS CAN BE MUCH MORE READILY UNDERSTOOD WHEN SIGNIFICANT RELATIONSHIPS AND IDEAS ARE SIMPLIFIED, EXAGGERATED, AND PRESENTED AS WORKING MODELS. THESE MODELS CAN BE CONSTRUCTED BY TEACHERS AND/OR STUDENTS. THE FOLLOWING CONSIDERATIONS SHOULD BE KEPT IN MIND--THE AID…
Three-dimensional contrasted visualization of pancreas in rats using clinical MRI and CT scanners.
Yin, Ting; Coudyzer, Walter; Peeters, Ronald; Liu, Yewei; Cona, Marlein Miranda; Feng, Yuanbo; Xia, Qian; Yu, Jie; Jiang, Yansheng; Dymarkowski, Steven; Huang, Gang; Chen, Feng; Oyen, Raymond; Ni, Yicheng
2015-01-01
The purpose of this work was to visualize the pancreas in post-mortem rats with local contrast medium infusion by three-dimensional (3D) magnetic resonance imaging (MRI) and computed tomography (CT) using clinical imagers. A total of 16 Sprague Dawley rats of about 300 g were used for the pancreas visualization. Following the baseline imaging, a mixed contrast medium dye called GadoIodo-EB containing optimized concentrations of Gd-DOTA, iomeprol and Evens blue was infused into the distally obstructed common bile duct (CBD) for post-contrast imaging with 3.0 T MRI and 128-slice CT scanners. Images were post-processed with the MeVisLab software package. MRI findings were co-registered with CT scans and validated with histomorphology, with relative contrast ratios quantified. Without contrast enhancement, the pancreas was indiscernible. After infusion of GadoIodo-EB solution, only the pancreatic region became outstandingly visible, as shown by 3D rendering MRI and CT and proven by colored dissection and histological examinations. The measured volume of the pancreas averaged 1.12 ± 0.04 cm(3) after standardization. Relative contrast ratios were 93.28 ± 34.61% and 26.45 ± 5.29% for MRI and CT respectively. We have developed a multifunctional contrast medium dye to help clearly visualize and delineate rat pancreas in situ using clinical MRI and CT scanners. The topographic landmarks thus created with 3D demonstration may help to provide guidelines for the next in vivo pancreatic MRI research in rodents.
Three-dimensional dynamic response analysis of earth dams
Mejia, L.H.
1981-01-01
The purpose of the present work has been to develop numerical techniques for the three-dimensional dynamic analysis of earth and rockfill dams and to study the dynamic behavior of embankment dams in three dimensions. A computer program suitable for the three-dimensional dynamic response analysis of earth dams was used to back-calculate the dynamic material properties of Oroville Dam from the recorded response of the dam to the August 1, 1975 Oroville earthquake. The dynamic response characteristics of earth dams which exhibit considerable three-dimensional behavior have been studied and the applicability of two-dimensional analysis to the computation of the dynamic response of such structures has been evaluated. Additionally, the effects that the degree of discretization in the cross-valley direction has on the computed three-dimensional dynamic response of earth dams have been studied. A K/sub 2/max value of 170 was found to be representative of the in-situ dynamic characteristics of the Oroville gravels. The three-dimensional effects of canyon geometry on the dynamic response of dams in triangular canyons were found to depend on the crest length to height ratio, L/H, of the dam. For dams with L/H greater than 7, these effects are small. The dynamic characteristics of these dams can, therefore, be simulated reasonably well using two-dimensional analyses. However, 2-D analyses cannot simulate correctly the dynamic response of dams in narrower canyons since the effects of canyon geometry for these dams are very pronounced.
Pregnancy sonogram; Obstetric ultrasonography; Obstetric sonogram; Ultrasound - pregnancy; IUGR - ultrasound; Intrauterine growth - ultrasound; Polyhydramnios - ultrasound; Oligohydramnios - ultrasound; ...
... Uterine bleeding - transvaginal ultrasound; Menstrual bleeding - transvaginal ultrasound; Infertility - transvaginal ultrasound; Ovarian - transvaginal ultrasound; Abscess - transvaginal ultrasound
Del Grande, N.K.; Dolan, K.W.; Durbin, P.F.; Gorvad, M.R.; Kornblum, B.T.; Perkins, D.E.; Schneberk, D.J.; Shapiro, A.B.
1993-04-01
We discuss three-dimensional (3D) dynamic thermal imaging of structure flaws using dual-band infrared (DBIR) computed tomography. Conventional thermography provides single-band infrared images which are difficult to interpret. Standard procedures yield imprecise (or qualitative) information about subsurface flaw sites which are typically masked by surface clutter. We use a DBIR imaging unique pioneered at LLNL to capture the time history of surface temperature difference for flash-heated targets. We relate these patterns to the location, size, shape and depth of subsurface flaws. We have demonstrated temperature accuracies of 0.2{degree}C, timing synchronizations of 3 ms (after onset of heat flash) and intervals of 42 ms, between images, during an 8 s cooling (and hearing) interval characterizing the front (and back) surface temperature-time history of an epoxy-glue disbond site in a flash-heated aluminum lap joint. This type of disbond played a significant role in causing damage to the Aloha Aircraft fuselage on the aged Boeing 737 jetliner. By ratioing DBIR images (near 5 and 10 micron), we located surface temperature patterns (generated by weak heat flow anomalies at subsurface flaw sites) and removed the emissivity mask (from surface roughness variations). We compared measurements with calculations from the three-dimensional, finite element computer code: TOPAZ3D. We combined infrared, ultrasound and x-ray imaging methods to characterize the lap joint disbond site spatial, bond quality, and material differences.
Three-dimensional photoacoustic imaging system with a 4f aspherical acoustic lens
NASA Astrophysics Data System (ADS)
Jen, En; Lin, Hsintien; Chiang, Huihua Kenny
2016-08-01
Photoacoustic (PA) imaging is a modality for achieving high-contrast images of blood vessels or tumors. Most PA imaging systems use complex reconstruction algorithms under conventional linear array transducers. We introduced the optical simulating method to improve the acoustic lens design and obtain a PA imaging system with improved spatial revolution (a 0.5-mm point spread function and a lateral image resolution of more than 1 mm) is realized using a 4f aspherical acoustic lens. The acoustic lens approach improved the image resolution and enabled direct reconstruction of three-dimensional (3-D) PA images. The system demonstrated a lateral resolution of more than 1 mm, a field of view of 8.5 deg, and a depth of focus of 10 mm. The system displays great potential for developing a real-time 3-D PA camera system for biomedical ultrasound imaging applications.
Mode-resolved travel-time statistics for elastic rays in three-dimensional billiards.
Ortega, A; Stringlo, K; Gorin, T
2012-03-01
We consider the ray limit of propagating ultrasound waves in three-dimensional bodies made from a homogeneous, isotropic, elastic material. Using a Monte Carlo approach, we simulate the propagation and proliferation of elastic rays using realistic angle-dependent reflection coefficients, taking into account mode conversion and ray splitting. For a few simple geometries, we analyze the long-time equilibrium distribution, focusing on the energy ratio between compressional and shear waves. Finally, we study the travel time statistics, i.e., the distribution of the amount of time a given trajectory spends as a compressional wave, as compared to the total travel time. These results are intimately related to recent elastodynamics experiments on Coda-wave interferometry by Lobkis and Weaver [Phys. Rev. E 78, 066212 (2008)].
Slightly two- or three-dimensional self-similar solutions
NASA Astrophysics Data System (ADS)
Sari, Re'em; Bode, Nate; Yalinewich, Almog; MacFadyen, Andrew
2012-08-01
Self-similarity allows for analytic or semi-analytic solutions to many hydrodynamics problems. Most of these solutions are one-dimensional. Using linear perturbation theory, expanded around such a one-dimensional solution, we find self-similar hydrodynamic solutions that are two- or three-dimensional. Since the deviation from a one-dimensional solution is small, we call these slightly two-dimensional and slightly three-dimensional self-similar solutions, respectively. As an example, we treat strong spherical explosions of the second type. A strong explosion propagates into an ideal gas with negligible temperature and density profile of the form ρ(r, θ, ϕ) = r-ω[1 + σF(θ, ϕ)], where ω > 3 and σ ≪ 1. Analytical solutions are obtained by expanding the arbitrary function F(θ, ϕ) in spherical harmonics. We compare our results with two-dimensional numerical simulations, and find good agreement.
Electroencephalographic (EEG) control of three-dimensional movement
NASA Astrophysics Data System (ADS)
McFarland, Dennis J.; Sarnacki, William A.; Wolpaw, Jonathan R.
2010-06-01
Brain-computer interfaces (BCIs) can use brain signals from the scalp (EEG), the cortical surface (ECoG), or within the cortex to restore movement control to people who are paralyzed. Like muscle-based skills, BCIs' use requires activity-dependent adaptations in the brain that maintain stable relationships between the person's intent and the signals that convey it. This study shows that humans can learn over a series of training sessions to use EEG for three-dimensional control. The responsible EEG features are focused topographically on the scalp and spectrally in specific frequency bands. People acquire simultaneous control of three independent signals (one for each dimension) and reach targets in a virtual three-dimensional space. Such BCI control in humans has not been reported previously. The results suggest that with further development noninvasive EEG-based BCIs might control the complex movements of robotic arms or neuroprostheses.
Three-dimensional natural convection in a narrow spherical shell
NASA Astrophysics Data System (ADS)
Liu, Ming; Egbers, Christoph
The convective motions in a shallow fluid layer between two concentric spheres in the presence of a constant axial force field have been studied numerically. The aspect ratio of the fluid layer to inner radius is beta =0.08, the Prandtl number Pra =37.5. A three-dimensional time-dependent numerical code is used to solve the governing equations in primitive variables. Convection in the sphe rical shell has then a highly three-dimensional nature. Characteristic flow patterns with a large number of banana-type cells, oriented in north-south direction and aligned in the azimuthal direction, are formed on the northern hemisphere, which grow gradually into the equatorial region accompanied by the generation of new cells as the Rayleigh number is increased. Various characteristics of these flows as well as their transient evolution are investigated for Rayleigh numbers up to 20 000.
Three-dimensional limaçon: Properties and applications
NASA Astrophysics Data System (ADS)
Kreismann, Jakob; Sinzinger, Stefan; Hentschel, Martina
2017-01-01
We perform electromagnetic wave simulations of fully three-dimensional optical limaçon microcavities, on the basis of their future applications in microlasers and photonic devices. The analysis of the three-dimensional modes and far fields reveals an increase of the quality factors as compared to the two-dimensional case. The structure of the far field in the third dimension shows pronounced maxima in the emission directionality inclined to the resonator plane which may be exploited for coupling the resonator modes to the environment. This triggers ideas for technical applications, such as the suggested sensor that can detect small changes in the environment based on changes in the emission profile.
Artificial three-dimensional niches deconstruct pancreas development in vitro.
Greggio, Chiara; De Franceschi, Filippo; Figueiredo-Larsen, Manuel; Gobaa, Samy; Ranga, Adrian; Semb, Henrik; Lutolf, Matthias; Grapin-Botton, Anne
2013-11-01
In the context of a cellular therapy for diabetes, methods for pancreatic progenitor expansion and subsequent differentiation into insulin-producing beta cells would be extremely valuable. Here we establish three-dimensional culture conditions in Matrigel that enable the efficient expansion of dissociated mouse embryonic pancreatic progenitors. By manipulating the medium composition we generate either hollow spheres, which are mainly composed of pancreatic progenitors, or complex organoids that spontaneously undergo pancreatic morphogenesis and differentiation. The in vitro maintenance and expansion of pancreatic progenitors require active Notch and FGF signaling, thus recapitulating in vivo niche signaling interactions. Our experiments reveal new aspects of pancreas development, such as a community effect by which small groups of cells better maintain progenitor properties and expand more efficiently than isolated cells, as well as the requirement for three-dimensionality. Finally, growth conditions in chemically defined biomaterials pave the way for testing the biophysical and biochemical properties of the niche that sustains pancreatic progenitors.
Three-dimensional control of Tetrahymena pyriformis using artificial magnetotaxis
NASA Astrophysics Data System (ADS)
Hyung Kim, Dal; Seung Soo Kim, Paul; Agung Julius, Anak; Jun Kim, Min
2012-01-01
We demonstrate three-dimensional control with the eukaryotic cell Tetrahymena pyriformis (T. pyriformis) using two sets of Helmholtz coils for xy-plane motion and a single electromagnet for z-direction motion. T. pyriformis is modified to have artificial magnetotaxis with internalized magnetite. To track the cell's z-axis position, intensity profiles of non-motile cells at varying distances from the focal plane are used. During vertical motion along the z-axis, the intensity difference is used to determine the position of the cell. The three-dimensional control of the live microorganism T. pyriformis as a cellular robot shows great potential for practical applications in microscale tasks, such as target transport and cell therapy.
MULTISHOCKED,THREE-DIMENSIONAL SUPERSONIC FLOWFIELDS WITH REAL GAS EFFECTS
NASA Technical Reports Server (NTRS)
Kutler, P.
1994-01-01
This program determines the supersonic flowfield surrounding three-dimensional wing-body configurations of a delta wing. It was designed to provide the numerical computation of three dimensional inviscid, flowfields of either perfect or real gases about supersonic or hypersonic airplanes. The governing equations in conservation law form are solved by a finite difference method using a second order noncentered algorithm between the body and the outermost shock wave, which is treated as a sharp discontinuity. Secondary shocks which form between these boundaries are captured automatically. The flowfield between the body and outermost shock is treated in a shock capturing fashion and therefore allows for the correct formation of secondary internal shocks . The program operates in batch mode, is in CDC update format, has been implemented on the CDC 7600, and requires more than 140K (octal) word locations.
COMOC: Three dimensional boundary region variant, programmer's manual
NASA Technical Reports Server (NTRS)
Orzechowski, J. A.; Baker, A. J.
1974-01-01
The three-dimensional boundary region variant of the COMOC computer program system solves the partial differential equation system governing certain three-dimensional flows of a viscous, heat conducting, multiple-species, compressible fluid including combustion. The solution is established in physical variables, using a finite element algorithm for the boundary value portion of the problem description in combination with an explicit marching technique for the initial value character. The computational lattice may be arbitrarily nonregular, and boundary condition constraints are readily applied. The theoretical foundation of the algorithm, a detailed description on the construction and operation of the program, and instructions on utilization of the many features of the code are presented.
Miniaturized digital holography sensor for distal three-dimensional endoscopy.
Kolenovic, Ervin; Osten, Wolfgang; Klattenhoff, Reiner; Lai, Songcan; von Kopylow, Christoph; Jüptner, Werner
2003-09-01
A miniaturized sensor head for endoscopic measurements based on digital holography is described. The system was developed to measure the shape and the three-dimensional deformation of objects located at places to which there is no access by common measurement systems. A miniaturized optical sensor, including a complete digital holographic interferometer with a CCD camera, is placed at the end of a flexible endoscope. The diameter of the head is smaller than 10 mm. The system enables interferometric measurements to be made at speeds of as many as five reconstructions per second, and it can be used outside the laboratory under normal environmental conditions. Shape measurements are performed with two wavelengths for contouring, and the deformation is measured by digital holographic interferometry. To obtain full three-dimensional data in displacement measurements we illuminate the object sequentially from three different illumination directions. To increase the lateral resolution we use temporal phase shifting.
Recent developments in three-dimensional numerical estuarine models
Cheng, Ralph T.; Smith, Peter E.; Casulli, Vincenzo
1993-01-01
For a fixed cost, computing power increases 5 to 10 times every five years. The readily available computing resources have inspired new modal formulations and innovative model applications. Significant progress has been advanced in three-dimensional numerical estuarine modeling within the past three or four years. This paper attempts to review and summarize properties of new 3-D estuarine hydrodynamic models. The emphasis of the review is placed on the formulation, numerical methods. The emphasis of the review is placed on the formulation, numerical methods, spatial and temporal resolution, computational efficiency, and turbulence closure of new models. Recent research has provided guidelines for the proper use of 3-D models involving in the σ-transformation. Other models resort to a fixed level discretization in the vertical. The semi-implicit treatment in time-stepping models appears to have gained momentum. Future research in three-dimensional numerical modeling remains to be on computational efficiency and turbulent closure.
Three-dimensional surface reconstruction for industrial computed tomography
NASA Technical Reports Server (NTRS)
Vannier, M. W.; Knapp, R. H.; Gayou, D. E.; Sammon, N. P.; Butterfield, R. L.; Larson, J. W.
1985-01-01
Modern high resolution medical computed tomography (CT) scanners can produce geometrically accurate sectional images of many types of industrial objects. Computer software has been developed to convert serial CT scans into a three-dimensional surface form, suitable for display on the scanner itself. This software, originally developed for imaging the skull, has been adapted for application to industrial CT scanning, where serial CT scans thrrough an object of interest may be reconstructed to demonstrate spatial relationships in three dimensions that cannot be easily understood using the original slices. The methods of three-dimensional reconstruction and solid modeling are reviewed, and reconstruction in three dimensions from CT scans through familiar objects is demonstrated.
Three-dimensional optical holography using a plasmonic metasurface
Huang, Lingling; Chen, Xianzhong; Mühlenbernd, Holger; Zhang, Hao; Chen, Shumei; Bai, Benfeng; Tan, Qiaofeng; Jin, Guofan; Cheah, Kok-Wai; Qiu, Cheng-Wei; Li, Jensen; Zentgraf, Thomas; Zhang, Shuang
2013-01-01
Benefitting from the flexibility in engineering their optical response, metamaterials have been used to achieve control over the propagation of light to an unprecedented level, leading to highly unconventional and versatile optical functionalities compared with their natural counterparts. Recently, the emerging field of metasurfaces, which consist of a monolayer of photonic artificial atoms, has offered attractive functionalities for shaping wave fronts of light by introducing an abrupt interfacial phase discontinuity. Here we realize three-dimensional holography by using metasurfaces made of subwavelength metallic nanorods with spatially varying orientations. The phase discontinuity takes place when the helicity of incident circularly polarized light is reversed. As the phase can be continuously controlled in each subwavelength unit cell by the rod orientation, metasurfaces represent a new route towards high-resolution on-axis three-dimensional holograms with a wide field of view. In addition, the undesired effect of multiple diffraction orders usually accompanying holography is eliminated.
Three-dimensional radiation transfer modeling in a dicotyledon leaf
NASA Astrophysics Data System (ADS)
Govaerts, Yves M.; Jacquemoud, Stéphane; Verstraete, Michel M.; Ustin, Susan L.
1996-11-01
The propagation of light in a typical dicotyledon leaf is investigated with a new Monte Carlo ray-tracing model. The three-dimensional internal cellular structure of the various leaf tissues, including the epidermis, the palisade parenchyma, and the spongy mesophyll, is explicitly described. Cells of different tissues are assigned appropriate morphologies and contain realistic amounts of water and chlorophyll. Each cell constituent is characterized by an index of refraction and an absorption coefficient. The objective of this study is to investigate how the internal three-dimensional structure of the tissues and the optical properties of cell constituents control the reflectance and transmittance of the leaf. Model results compare favorably with laboratory observations. The influence of the roughness of the epidermis on the reflection and absorption of light is investigated, and simulation results confirm that convex cells in the epidermis focus light on the palisade parenchyma and increase the absorption of radiation.
High-resolution three-dimensional imaging radar
NASA Technical Reports Server (NTRS)
Cooper, Ken B. (Inventor); Chattopadhyay, Goutam (Inventor); Siegel, Peter H. (Inventor); Dengler, Robert J. (Inventor); Schlecht, Erich T. (Inventor); Mehdi, Imran (Inventor); Skalare, Anders J. (Inventor)
2010-01-01
A three-dimensional imaging radar operating at high frequency e.g., 670 GHz, is disclosed. The active target illumination inherent in radar solves the problem of low signal power and narrow-band detection by using submillimeter heterodyne mixer receivers. A submillimeter imaging radar may use low phase-noise synthesizers and a fast chirper to generate a frequency-modulated continuous-wave (FMCW) waveform. Three-dimensional images are generated through range information derived for each pixel scanned over a target. A peak finding algorithm may be used in processing for each pixel to differentiate material layers of the target. Improved focusing is achieved through a compensation signal sampled from a point source calibration target and applied to received signals from active targets prior to FFT-based range compression to extract and display high-resolution target images. Such an imaging radar has particular application in detecting concealed weapons or contraband.
Three-dimensional structure of Erwinia carotovora L-asparaginase
Kislitsyn, Yu. A. Kravchenko, O. V.; Nikonov, S. V. Kuranova, I. P.
2006-10-15
Three-dimensional structure of Erwinia carotovora L-asparaginase, which has antitumor activity and is used for the treatment of acute lymphoblastic leukemia, was solved at 3 A resolution and refined to R{sub cryst} = 20% and R{sub free} = 28%. Crystals of recombinant Erwinia carotovora L-asparaginase were grown by the hanging-drop vapor-diffusion method from protein solutions in a HEPES buffer (pH 6.5) and PEG MME 5000 solutions in a cacodylate buffer (pH 6.5) as the precipitant. Three-dimensional X-ray diffraction data were collected up to 3 A resolution from one crystal at room temperature. The structure was solved by the molecular replacement method using the coordinates of Erwinia chrysanthemi L-asparaginase as the starting model. The coordinates refined with the use of the CNS program package were deposited in the Protein Data Bank (PDB code 1ZCF)
Three-dimensional simulations of Nova capsule implosion experiments
Marinak, M.M.; Tipton, R.E.; Landen, O.L.
1995-11-01
Capsule implosion experiments carried out on the Nova laser are simulated with the three-dimensional HYDRA radiation hydrodynamics code. Simulations of ordered near single mode perturbations indicate that structures which evolve into round spikes can penetrate farthest into the hot spot. Bubble-shaped perturbations can burn through the capsule shell fastest, however, causing even more damage. Simulations of a capsule with multimode perturbations shows spike amplitudes evolving in good agreement with a saturation model during the deceleration phase. The presence of sizable low mode asymmetry, caused either by drive asymmetry or perturbations in the capsule shell, can dramatically affect the manner in which spikes approach the center of the hot spot. Three-dimensional coupling between the low mode shell perturbations intrinsic to Nova capsules and the drive asymmetry brings the simulated yields into closer agreement with the experimental values.
On anisotropic versions of three-dimensional pentamode metamaterials
NASA Astrophysics Data System (ADS)
Kadic, Muamer; Bückmann, Tiemo; Schittny, Robert; Wegener, Martin
2013-02-01
Pentamode materials are artificial solids with elastic properties that approximate those of isotropic liquids. The corresponding three-dimensional mechanical metamaterials or ‘meta-liquids’ have recently been fabricated. In contrast to normal liquids, anisotropic meta-liquids are also possible—a prerequisite for realizing many of the envisioned transformation-elastodynamics architectures. Here, we study several possibilities theoretically for introducing intentional anisotropy into three-dimensional pentamode metamaterials. In static continuum mechanics, the transition from anti-auxetic pentamode materials to auxetics is possible. Near this transition, in the dynamic case, approximately uniaxial versions of pentamode metamaterials deliver anisotropic longitudinal-wave phase velocities different by nearly a factor of 10 for realistically accessible microstructure parameters.
Three-dimensional tissue culture based on magnetic cell levitation.
Souza, Glauco R; Molina, Jennifer R; Raphael, Robert M; Ozawa, Michael G; Stark, Daniel J; Levin, Carly S; Bronk, Lawrence F; Ananta, Jeyarama S; Mandelin, Jami; Georgescu, Maria-Magdalena; Bankson, James A; Gelovani, Juri G; Killian, T C; Arap, Wadih; Pasqualini, Renata
2010-04-01
Cell culture is an essential tool in drug discovery, tissue engineering and stem cell research. Conventional tissue culture produces two-dimensional cell growth with gene expression, signalling and morphology that can be different from those found in vivo, and this compromises its clinical relevance. Here, we report a three-dimensional tissue culture based on magnetic levitation of cells in the presence of a hydrogel consisting of gold, magnetic iron oxide nanoparticles and filamentous bacteriophage. By spatially controlling the magnetic field, the geometry of the cell mass can be manipulated, and multicellular clustering of different cell types in co-culture can be achieved. Magnetically levitated human glioblastoma cells showed similar protein expression profiles to those observed in human tumour xenografts. Taken together, these results indicate that levitated three-dimensional culture with magnetized phage-based hydrogels more closely recapitulates in vivo protein expression and may be more feasible for long-term multicellular studies.
Three-Dimensional Modeling of Guide-Field Magnetic Reconnection
NASA Technical Reports Server (NTRS)
Hesse, Michael
2005-01-01
The dissipation mechanism of guide field magnetic reconnection remains a subject of intense scientific interest. On one hand, one set of recent studies have shown that particle inertia-based processes, which include thermal and bulk inertial effects, provide the reconnection electric field in the diffusion region. On the other hand, a second set of studies emphasizes the role of wave-particle interactions in providing anomalous resistivity in the diffusion region. In this presentation, we analyze three-dimensional PIC simulations of guide-field magnetic reconnection. Specific emphasis will be on the question whether thermal-inertia processes, mediated by the electron pressure tensor, remain a viable dissipation mechanism in fully three-dimensional systems.
Nonisentropic unsteady three dimensional small disturbance potential theory
NASA Technical Reports Server (NTRS)
Gibbons, M. D.; Whitlow, W., Jr.; Williams, M. H.
1986-01-01
Modifications that allow for more accurate modeling of flow fields when strong shocks are present were made into three dimensional transonic small disturbance (TSD) potential theory. The Engquist-Osher type-dependent differencing was incorporated into the solution algorithm. The modified theory was implemented in the XTRAN3S computer code. Steady flows over a rectangular wing with a constant NACA 0012 airfoil section and an aspect ratio of 12 were calculated for freestream Mach numbers (M) of 0.82, 0.84, and 0.86. The obtained results are compared using the modified and unmodified TSD theories and the results from a three dimensional Euler code are presented. Nonunique solutions in three dimensions are shown to appear for the rectangular wing as aspect ratio increases. Steady and unsteady results are shown for the RAE tailplane model at M = 0.90. Calculations using unmodified theory, modified theory and experimental data are compared.
Three-dimensional coherence of light speckles: Experiment
Magatti, D.; Gatti, A.; Ferri, F.
2009-05-15
We provide an experimental detailed study of the three-dimensional coherence properties of light speckles produced by different tunable pseudothermal sources. Our findings confirm the theoretical prediction of the companion article [A. Gatti et al., Phys. Rev. A 78, 063806 (2008)], according to which the longitudinal coherence of the speckles is ruled by ordinary diffraction laws only in the deep-Fresnel zone close to the source, deviates from this behavior in the Fresnel zone, and tends to become infinite when approaching the Fraunhofer zone. A quantitative comparison with theory is presented for Gaussian speckles in all the three regimes and for Airy speckles in the deep-Fresnel zone. Potential applications to three-dimensional imaging techniques are briefly discussed.
Three-dimensional simulation study of ionospheric plasma clouds
NASA Technical Reports Server (NTRS)
Zalesak, S. T.; Drake, J. F.; Huba, J. D.
1990-01-01
The results of fully three-dimensional numerical simulations of ionospheric plasma cloud evolution are presented. The evolution of the plasma cloud considered by Drake and Huba (1987) in the limit of vanishingly small ion compressibility is discussed. Simulations support the results of the analytical theory: finite plasma temperature, combined with fully three-dimensional plasma dynamics, is a stabilizing influence on plasma cloud evolution. This stability is associated with sheared azimuthal ion flows in the vicinity of the cloud surface. Cloud evolution using realistic values of ion compressibility show that the cloud rapidly diffuses to a state in which the sheared azimuthal flow is substantially reduced; subsequently, the cloud becomes unstable and structures.
Three-dimensional potential energy surface of Ar–CO
Sumiyoshi, Yoshihiro; Endo, Yasuki
2015-01-14
A three-dimensional intermolecular potential energy surface of the Ar–CO complex has been determined by fitting most of the previously reported spectroscopic data, where observed transition frequencies by microwave, millimeter-wave, submillimeter-wave, and infrared spectroscopy were reproduced simultaneously within their experimental accuracies. A free rotor model Hamiltonian considering all the freedom of motions for an atom-diatom system was applied to calculate vibration-rotation energies. A three-dimensional potential energy surface obtained by ab initio calculations at the CCSD(T)-F12b/aug-cc-pV5Z level of theory was parameterized by a model function consisting of 46 parameters. They were used as initial values for the least-squares analysis of the experimental data. A total of 20 parameters were optimized to reproduce all the spectroscopic data.
Three-dimensional reconstruction of coronal mass ejections
NASA Technical Reports Server (NTRS)
Jackson, Bernard V.; Hick, Paul
1994-01-01
Computer assisted tomography (CAT) techniques are used to reconstruct the three dimensional shape of coronal mass ejections in the interplanetary medium. Both the Helios 2 spacecraft zodiacal-light photometers and the Solwind coronograph measure changes in Thomson scattering of sunlight from electrons. The technique from near-perpendicular Solwind and Helios views are applied to determine the density of a mass ejection which left the solar surface on 24 May 1979. The coronograph and the Helios perspective views are not simultaneous; the Solwind observations extend outward to sky plane distances of only 10 of the solar radius, whereas the Helios 16 photometer observes to as close as 17 of the solar radius from the sun. The solution is obtained by assuming outward radial expansion and that the coronal mass ejections (CME's) have the same speed everywhere at the same height. The analyses show that CME's are extensive three dimensional structures (the CME of 24 May appears approximately shell) like in three dimensions.
Three-dimensional potential energy surface of Ar-CO.
Sumiyoshi, Yoshihiro; Endo, Yasuki
2015-01-14
A three-dimensional intermolecular potential energy surface of the Ar-CO complex has been determined by fitting most of the previously reported spectroscopic data, where observed transition frequencies by microwave, millimeter-wave, submillimeter-wave, and infrared spectroscopy were reproduced simultaneously within their experimental accuracies. A free rotor model Hamiltonian considering all the freedom of motions for an atom-diatom system was applied to calculate vibration-rotation energies. A three-dimensional potential energy surface obtained by ab initio calculations at the CCSD(T)-F12b/aug-cc-pV5Z level of theory was parameterized by a model function consisting of 46 parameters. They were used as initial values for the least-squares analysis of the experimental data. A total of 20 parameters were optimized to reproduce all the spectroscopic data.
Three-Dimensional Flow in Compressors and Channels.
1985-11-01
case where shock waves occur, were begun. Considerable effort was expanded upon the problem by both principal investigators, Dr. R. * L. Enlow , visiting...done by Dr. Enlow ()was presented at the Second Australian * Mathematics Convention. 9 Because the flow relative to the blades has a gradient, the angle...34Transonic Shear Flow in a Three-Dimensional Channel," Technical Report N00014-79-C-0285-T, January 1981. 6. Enlow , R.L., "Wavefront Propagation in Non
Three-dimensional Analysis of Nanomaterials by Scanning Probe Nanotomography
NASA Astrophysics Data System (ADS)
Efimov, Anton E.; Agapova, Olga I.; Mochalov, Konstantin E.; Agapov, Igor I.
Micro and nanostructure of scaffolds made from fibroin of Bombyx mori silkworm by salt leaching technique was studied by scanning probe nanotomography. Nanopores with dimensions in range from 30 to 180 nm are observed in the scaffold volume. Three - dimensional analysis of obtained data shows that degree of scaffold nanoporosity is 0.5% and nanopores are not interconnected with each other. Usage of scanning probe nanotomography technique enables to obtain unique nanoscale information of 3D structure of biopolymer nanomaterials.
Rapid measurement of three-dimensional diffusion tensor
NASA Astrophysics Data System (ADS)
Cho, H.; Ren, X.-H.; Sigmund, E. E.; Song, Y.-Q.
2007-04-01
In this article, the authors demonstrate a rapid NMR method to measure a full three-dimensional diffusion tensor. This method is based on a multiple modulation multiple echo sequence and utilizes static and pulsed magnetic field gradients to measure diffusion along multiple directions simultaneously. The pulse sequence was optimized using a well-known linear inversion metric (condition number) and successfully tested on both isotropic (water) and anisotropic (asparagus) diffusion systems.
Three-dimensional inelastic analysis methods for hot section components
NASA Technical Reports Server (NTRS)
Todd, E. S.
1987-01-01
The objective of this program is to produce a series of new computer codes that permit more accurate and efficient three-dimensional inelastic structural analysis of combustor liners, turbine blades, and turbine vanes. Each code embodies a progression of mathematical models for increasingly comprehensive representation of the geometrical features, loading conditions, and forms of nonlinear material response that distinguish these three groups of hot section components.
Multi-cellular, three-dimensional living mammalian tissue
NASA Technical Reports Server (NTRS)
Goodwin, Thomas J. (Inventor); Wolf, David A. (Inventor)
1994-01-01
The present invention relates to a multicellular, three-dimensional, living mammalian tissue. The tissue is produced by a co-culture process wherein two distinct types of mammalian cells are co-cultured in a rotating bioreactor which is completely filled with culture media and cell attachment substrates. As the size of the tissue assemblies formed on the attachment substrates changes, the rotation of the bioreactor is adjusted accordingly.
Simulating Photons and Plasmons in a Three-dimensional Lattice
Pletzer, A.; Shvets, G.
2002-09-03
Three-dimensional metallic photonic structures are studied using a newly developed mixed finite element-finite difference (FE-FD) code, Curly3d. The code solves the vector Helmholtz equation as an eigenvalue problem in the unit cell of a triply periodic lattice composed of conductors and/or dielectrics. The mixed FE-FD discretization scheme ensures rapid numerical convergence of the eigenvalue and allows the code to run at low resolution. Plasmon and photonic band structure calculations are presented.
Code System for Three-Dimensional Hydraulic Reactor Core Analysis.
ROBERT,; BENEDETTI, L.
2001-03-05
Version 00 SCORE-EVET was developed to study multidimensional transient fluid flow in nuclear reactor fuel rod arrays. The conservation equations used were derived by volume averaging the transient compressible three-dimensional local continuum equations in Cartesian coordinates. No assumptions associated with subchannel flow have been incorporated into the derivation of the conservation equations. In addition to the three-dimensional fluid flow equations, the SCORE-EVET code contains a one-dimensional steady state solution scheme to initialize the flow field, steady state and transient fuel rod conduction models, and comprehensive correlation packages to describe fluid-to-fuel rod interfacial energy and momentum exchange. Velocity and pressure boundary conditions can be specified as a function of time and space to model reactor transient conditions, such as a hypothesized loss-of-coolant accident (LOCA) or flow blockage. The basic volume-averaged transient three-dimensional equations for flow in porous media are solved in their general form with constitutive relationships and boundary conditions tailored to define the porous medium as a matrix of fuel rods. By retaining generality in the form of the conservation equations, a wide range of fluid flow problem configurations, from computational regions representing a single fuel rod subchannel to multichannels, or even regions without a fuel rod, can be modeled without restrictive assumptions. The completeness of the conservation equations has allowed SCORE-EVET to be used, with modification to the constitutive relationships, to calculate three-dimensional laminar boundary layer development, flow fields in large bodies of water, and, with the addition of a turbulence model, turbulent flow in pipe expansions and tees.
Three-dimensional stiffness of the carpal arch.
Gabra, Joseph N; Li, Zong-Ming
2016-01-04
The carpal arch of the wrist is formed by irregularly shaped carpal bones interconnected by numerous ligaments, resulting in complex structural mechanics. The purpose of this study was to determine the three-dimensional stiffness characteristics of the carpal arch using displacement perturbations. It was hypothesized that the carpal arch would exhibit an anisotropic stiffness behavior with principal directions that are oblique to the conventional anatomical axes. Eight (n=8) cadavers were used in this study. For each specimen, the hamate was fixed to a custom stationary apparatus. An instrumented robot arm applied three-dimensional displacement perturbations to the ridge of trapezium and corresponding reaction forces were collected. The displacement-force data were used to determine a three-dimensional stiffness matrix using least squares fitting. Eigendecomposition of the stiffness matrix was used to identify the magnitudes and directions of the principal stiffness components. The carpal arch structure exhibited anisotropic stiffness behaviors with a maximum principal stiffness of 16.4±4.6N/mm that was significantly larger than the other principal components of 3.1±0.9 and 2.6±0.5N/mm (p<0.001). The principal direction of the maximum stiffness was pronated within the cross section of the carpal tunnel which is accounted for by the stiff transverse ligaments that tightly bind distal carpal arch. The minimal principal stiffness is attributed to the less constraining articulation between the trapezium and scaphoid. This study provides advanced characterization of the wrist׳s three-dimensional structural stiffness for improved insight into wrist biomechanics, stability, and function.
Three-dimensional compressible and stretchable conductive composites.
Yu, You; Zeng, Jifang; Chen, Chaojian; Xie, Zhuang; Guo, Ruisheng; Liu, Zhilu; Zhou, Xuechang; Yang, Yong; Zheng, Zijian
2014-02-01
Three-dimensional (3D) conductive composites with remarkable flexibility, compressibility, and stretchability are fabricated by solution deposition of thin metal coatings on chemically modified, macroscopically continuous, 3D polyurethane sponges, followed by infiltration of the metallic sponges with polydimethylsiloxane (PDMS). These low-cost conductive composites are used as high-performance interconnects for flexible and stretchable light-emitting diode (LED) arrays, even with severe surface abrasion or cutting.
Time-Domain Simulation of Three Dimensional Quantum Wires
Mossman, Sean; Kuzyk, Mark G.
2016-01-01
A method is presented to calculate the eigenenergies and eigenfunctions of quantum wires. This is a true three-dimensional method based on a direct implementation of the time-dependent Schrödinger equation. It makes no approximations to the Schrödinger equation other than the finite-difference approximation of the space and time derivatives. The accuracy of our method is tested by comparing it to analytical results in a cylindrical wire. PMID:27124603
Three-dimensional surface reconstruction from multistatic SAR images.
Rigling, Brian D; Moses, Randolph L
2005-08-01
This paper discusses reconstruction of three-dimensional surfaces from multiple bistatic synthetic aperture radar (SAR) images. Techniques for surface reconstruction from multiple monostatic SAR images already exist, including interferometric processing and stereo SAR. We generalize these methods to obtain algorithms for bistatic interferometric SAR and bistatic stereo SAR. We also propose a framework for predicting the performance of our multistatic stereo SAR algorithm, and, from this framework, we suggest a metric for use in planning strategic deployment of multistatic assets.
A Three Dimensional Non-Singular Modelling of Rigid Manipulators.
1987-12-01
511111 OTC FILE COPY (1) ’ NAVAL POSTGRADUATE SCHOOL 0 ’ Monterey, California IDTIC I{ IELECTE S MAR 08 8 f 0? THESIS A THREE DIMENSIONAL NON-SINGULAR...MODELLING OF RIGID MANIPULATORS by Sadrettin Altinok December 1987 Thesis Advisor D.L. Smith Approved for public release; distribution is unlimited. 88...MASTERS THESIS FROM _ TO 1987 DECEMBER iC 6 16 SUPPLEMENTARY NOTATION 17 COSA T i CODES 18 SUBJECT TERMS (Continue on reverse f necessary and identify by
Three-dimensional terahertz computed tomography of human bones.
Bessou, Maryelle; Chassagne, Bruno; Caumes, Jean-Pascal; Pradère, Christophe; Maire, Philippe; Tondusson, Marc; Abraham, Emmanuel
2012-10-01
Three-dimensional terahertz computed tomography has been used to investigate dried human bones such as a lumbar vertebra, a coxal bone, and a skull, with a direct comparison with standard radiography. In spite of lower spatial resolution compared with x-ray, terahertz imaging clearly discerns a compact bone from a spongy one, with strong terahertz absorption as shown by additional terahertz time-domain transmission spectroscopy.
Separation behavior of boundary layers on three-dimensional wings
NASA Technical Reports Server (NTRS)
Stock, H. W.
1981-01-01
An inverse boundary layer procedure for calculating separated, turbulent boundary layers at infinitely long, crabbing wing was developed. The procedure was developed for calculating three dimensional, incompressible turbulent boundary layers was expanded to adiabatic, compressible flows. Example calculations with transsonic wings were made including viscose effects. In this case an approximated calculation method described for areas of separated, turbulent boundary layers, permitting calculation of this displacement thickness. The laminar boundary layer development was calculated with inclined ellipsoids.
Three dimensional tracking with misalignment between display and control axes
NASA Technical Reports Server (NTRS)
Ellis, Stephen R.; Tyler, Mitchell; Kim, Won S.; Stark, Lawrence
1992-01-01
Human operators confronted with misaligned display and control frames of reference performed three dimensional, pursuit tracking in virtual environment and virtual space simulations. Analysis of the components of the tracking errors in the perspective displays presenting virtual space showed that components of the error due to visual motor misalignment may be linearly separated from those associated with the mismatch between display and control coordinate systems. Tracking performance improved with several hours practice despite previous reports that such improvement did not take place.
Anomalous three-dimensional symmetries of solar-wind plasma.
Bershadskii, A
2002-10-01
An example of a combination of Kolmogorov three-dimensional properties with Alfvén two-dimensional properties in solar-wind plasma is given using recent data obtained with the Advanced Composition Explorer satellite at the L1 libration point. Both spectral and moments scaling analyses are used to demonstrate the possibility of such a combination. Two-decade scaling and the large number of the scaling exponents under consideration indicate the robustness of this observation.
Three-Dimensional DNA Nanostructures Assembled from DNA Star Motifs.
Tian, Cheng; Zhang, Chuan
2017-01-01
Tile-based DNA self-assembly is a promising method in DNA nanotechnology and has produced a wide range of nanostructures by using a small set of unique DNA strands. DNA star motif, as one of DNA tiles, has been employed to assemble varieties of symmetric one-, two-, three-dimensional (1, 2, 3D) DNA nanostructures. Herein, we describe the design principles, assembly methods, and characterization methods of 3D DNA nanostructures assembled from the DNA star motifs.
Development of three-dimensional memory (3D-M)
NASA Astrophysics Data System (ADS)
Yu, Hong-Yu; Shen, Chen; Jiang, Lingli; Dong, Bin; Zhang, Guobiao
2016-10-01
Since the invention of 3-D ROM in 1996, three-dimensional memory (3D-M) has been under development for nearly two decades. In this presentation, we'll review the 3D-M history and compare different 3D-Ms (including 3D-OTP from Matrix Semiconductor, 3D-NAND from Samsung and 3D-XPoint from Intel/Micron).
Coherent states on horospheric three-dimensional Lobachevsky space
NASA Astrophysics Data System (ADS)
Kurochkin, Yu.; Rybak, I.; Shoukavy, Dz.
2016-08-01
In the paper it is shown that due to separation of variables in the Laplace-Beltrami operator (Hamiltonian of a free quantum particle) in horospheric and quasi-Cartesian coordinates of three dimensional Lobachevsky space, it is possible to introduce standard ("conventional" according to Perelomov [Generalized Coherent States and Their Applications (Springer-Verlag, 1986), p. 320]) coherent states. Some problems (oscillator on horosphere, charged particle in analogy of constant uniform magnetic field) where coherent states are suitable for treating were considered.
Three dimensional flow computations in a turbine scroll
NASA Technical Reports Server (NTRS)
Hamed, A.; Ghantous, C. A.
1982-01-01
The compressible three dimensional inviscid flow in the scroll and vaneless nozzle of radial inflow turbines is analyzed. A FORTRAN computer program for the numerical solution of this complex flow field using the finite element method is presented. The program input consists of the mass flow rate and stagnation conditions at the scroll inlet and of the finite element discretization parameters and nodal coordinates. The output includes the pressure, Mach number and velocity magnitude and direction at all the nodal points.
Characteristic boundary conditions for three-dimensional transonic unsteady aerodynamics
NASA Technical Reports Server (NTRS)
Whitlow, W., Jr.
1984-01-01
Characteristic far-field boundary conditions for the three-dimensional unsteady transonic small disturbance potential equation have been developed. The boundary conditions were implemented in the XTRAN3S finite difference code and tested for a flat plate rectangular wing with a pulse in angle of attack; the freestream Mach number was 0.85. The calculated force response shows that the characteristic boundary conditions reduce disturbances that are reflected from the computational boundaries.
Purification Techniques for Three-Dimensional DNA Nanostructures.
Meyer, Travis A
2017-01-01
Separation of self-assembled three-dimensional nanostructures from excess staple strands, misfolded structures, or unattached functional elements is critical for downstream applications. Numerous purification techniques exist, with varying yields, purities, and hetero-element compatibilities. In this chapter, we focus on three such techniques-agarose gel electrophoresis, ultrafiltration, and polymeric bead pull-down-which together satisfy requirements for a range of applications.
Fully Three-Dimensional Virtual-Reality System
NASA Technical Reports Server (NTRS)
Beckman, Brian C.
1994-01-01
Proposed virtual-reality system presents visual displays to simulate free flight in three-dimensional space. System, virtual space pod, is testbed for control and navigation schemes. Unlike most virtual-reality systems, virtual space pod would not depend for orientation on ground plane, which hinders free flight in three dimensions. Space pod provides comfortable seating, convenient controls, and dynamic virtual-space images for virtual traveler. Controls include buttons plus joysticks with six degrees of freedom.
Three-dimensional chiral skyrmions with attractive interparticle interactions
NASA Astrophysics Data System (ADS)
Leonov, A. O.; Monchesky, T. L.; Loudon, J. C.; Bogdanov, A. N.
2016-09-01
We introduce a new class of isolated three-dimensional skyrmion that can occur within the cone phase of chiral magnetic materials. These novel solitonic states consist of an axisymmetric core separated from the host phase by an asymmetric shell. These skyrmions attract one another. We derive regular solutions for isolated skyrmions arising in the cone phase of cubic helimagnets and investigate their bound states.
Four-Dimensional Entropy from Three-Dimensional Gravity.
Carlip, S
2015-08-14
At the horizon of a black hole, the action of (3+1)-dimensional loop quantum gravity acquires a boundary term that is formally identical to an action for three-dimensional gravity. I show how to use this correspondence to obtain the entropy of the (3+1)-dimensional black hole from well-understood conformal field theory computations of the entropy in (2+1)-dimensional de Sitter space.
Reentrance and ultrametricity in three-dimensional Ising spin glasses
NASA Astrophysics Data System (ADS)
Katzgraber, Helmut G.; Thomas, Creighton K.; Hartmann, Alexander K.
2012-02-01
We study the three-dimensional Edwards-Anderson Ising spin glass with bimodal disorder with a fraction of 22.8% antiferromagnetic bonds. Parallel tempering Monte Carlo simulations down to very low temperatures show that for this fraction of antiferromagnetic bonds the phase diagram of the system is reentrant, in agreement with previous results. Furthemore, using a clustering analysis, we analyze the ultrametric properties of phase space for this model.
Three-dimensional range imaging apparatus and method
NASA Technical Reports Server (NTRS)
Scott, Vibart Stan (Inventor); Blair, James Bryan (Inventor); Izquierdo, Luis R. (Inventor)
2011-01-01
A three-dimensional range imager includes a light source for providing a modulated light signal, a multiplexer, an optical fiber connecting the light source to the multiplexer, a plurality of optical fibers connected at first ends to the multiplexer and at second ends to a first fiber array, and a transmitter optic disposed adjacent the first fiber array for projecting a pixel pattern of the array onto a target.
Convection Effects in Three-dimensional Dendritic Growth
NASA Technical Reports Server (NTRS)
Lu, Yili; Beckermann, C.; Karma, A.
2003-01-01
A phase-field model is developed to simulate free dendritic growth coupled with fluid flow for a pure material in three dimensions. The preliminary results presented here illustrate the strong influence of convection on the three-dimensional (3D) dendrite growth morphology. The detailed knowledge of the flow and temperature fields in the melt around the dendrite from the simulations allows for a detailed understanding of the convection effects on dendritic growth.
Three-dimensional separated flows past ground vehicles
NASA Technical Reports Server (NTRS)
Chometon, F.; Fontanet, P.
1981-01-01
The separated flow past a thick body is calculated using a theoretical model based on a discrete wake-vortex representation. Rehbach's unsteady inviscid scheme (1977) was used in the three-dimensional analysis. The obstacle is represented by singularities, and the wake is modeled by vortex particles emitted at the separation line. Calculated results for an axisymmetric body are compared with flow visualization results.
Three-Dimensional Stiffness of the Carpal Arch
Gabra, Joseph N.; Li, Zong-Ming
2015-01-01
The carpal arch of the wrist is formed by irregularly shaped carpal bones interconnected by numerous ligaments, resulting in complex structural mechanics. The purpose of this study was to determine the three-dimensional stiffness characteristics of the carpal arch using displacement perturbations. It was hypothesized that the carpal arch would exhibit an anisotropic stiffness behavior with principal directions that are oblique to the conventional anatomical axes. Eight (n = 8) cadavers were used in this study. For each specimen, the hamate was fixed to a custom stationary apparatus. An instrumented robot arm applied three-dimensional displacement perturbations to the ridge of trapezium and corresponding reaction forces were collected. The displacement-force data were used to determine a three-dimensional stiffness matrix using least squares fitting. Eigendecomposition of the stiffness matrix was used to identify the magnitudes and directions of the principal stiffness components. The carpal arch structure exhibited anisotropic stiffness behaviors with a maximum principal stiffness of 16.4 ± 4.6 N/mm that was significantly larger than the other principal components of 3.1 ± 0.9 and 2.6 ± 0.5 N/mm (p < 0.001). The principal direction of the maximum stiffness was pronated within the cross section of the carpal tunnel which is accounted for by the stiff transverse ligaments that tightly bind distal carpal arch. The minimal principal stiffness is attributed to the less constraining articulation between the trapezium and scaphoid. This study provides advanced characterization of the wrist's three-dimensional structural stiffness for improved insight into wrist biomechanics, stability, and function. PMID:26617368
Calculation of three-dimensional, inviscid supersonic, steady flows
NASA Technical Reports Server (NTRS)
Moretti, G.
1982-01-01
A numerical technique is described for the calculation of three dimensional, inviscid, supersonic, steady flows over wing-body configurations. A high degree of accuracy without increasing the number of computational nodes is obtained by means of a powerful conformal mapping technique. Results are presented for some simple body configurations and for a more complex arrow wing airframe. The numerical results show good agreement with experimental measurements.
Advanced three-dimensional dynamic analysis by boundary element methods
NASA Technical Reports Server (NTRS)
Banerjee, P. K.; Ahma, S.
1985-01-01
Advanced formulations of boundary element method for periodic, transient transform domain and transient time domain solution of three-dimensional solids have been implemented using a family of isoparametric boundary elements. The necessary numerical integration techniques as well as the various solution algorithms are described. The developed analysis has been incorporated in a fully general purpose computer program BEST3D which can handle up to 10 subregions. A number of numerical examples are presented to demonstrate the accuracy of the dynamic analyses.
Linear stability theory and three-dimensional boundary layer transition
NASA Technical Reports Server (NTRS)
Spall, Robert E.; Malik, Mujeeb R.
1992-01-01
The viewgraphs and discussion of linear stability theory and three dimensional boundary layer transition are provided. The ability to predict, using analytical tools, the location of boundary layer transition over aircraft-type configurations is of great importance to designers interested in laminar flow control (LFC). The e(sup N) method has proven to be fairly effective in predicting, in a consistent manner, the location of the onset of transition for simple geometries in low disturbance environments. This method provides a correlation between the most amplified single normal mode and the experimental location of the onset of transition. Studies indicate that values of N between 8 and 10 correlate well with the onset of transition. For most previous calculations, the mean flows were restricted to two-dimensional or axisymmetric cases, or have employed simple three-dimensional mean flows (e.g., rotating disk, infinite swept wing, or tapered swept wing with straight isobars). Unfortunately, for flows over general wing configurations, and for nearly all flows over fuselage-type bodies at incidence, the analysis of fully three-dimensional flow fields is required. Results obtained for the linear stability of fully three-dimensional boundary layers formed over both wing and fuselage-type geometries, and for both high and low speed flows are discussed. When possible, transition estimates form the e(sup N) method are compared to experimentally determined locations. The stability calculations are made using a modified version of the linear stability code COSAL. Mean flows were computed using both Navier Stokes and boundary-layer codes.
Computational Study of Colloidal Droplet Interactions with Three Dimensional Structures
2015-05-18
SECURITY CLASSIFICATION OF: The colloidal droplet spreading on and sorption into a porous medium is important to 3D printing technology. In this study... colloidal fluid distribution in the porous structure after sorption of single/multiple droplets in powder beds. The spreading of the droplet on the surface...Feb-2015 Approved for Public Release; Distribution Unlimited Final Report: Computational Study of Colloidal Droplet Interactions with Three Dimensional
Three-dimensional models. [For orbital celestial mechanics
Hunter, C. )
1990-06-01
The Schwarzschild (1979) approach to the analysis of three-dimensional galactic models is reviewed. An analysis of triaxial Staeckel models is discussed which shows that such models have a wide variety of possible distribution functions. The uniqueness that Schwarzschild first encountered in his discrete formulation of the problem of finding a three-integral distribution function for a triaxial density is real and not an artifact of the finite cell approximation. 27 refs.
Three-Dimensional Visualization of Ozone Process Data.
1997-06-18
analysis . Process analysis data refers to the individual rates associated with the different processes (advection, diffusion, deposition, and chemical...are completed, a process analysis method retains these rates for analysis into which factors are most significantly impacting the accumulation of ozone in the troposphere....goal of this research is to find means and methods of coupling air quality data to three-dimensional visualization in order to enhance ozone process
Scaffold informatics and biomimetic design: three-dimensional medical reconstruction.
da Silva, Jorge Vicente Lopes; Martins, Tatiana Al-Chueyr Pereira; Noritomi, Pedro Yoshito
2012-01-01
This chapter briefly describes the concepts underlying medical imaging reconstruction and the requirements for its integration with subsequent applications as BioCAD, rapid prototyping (RP), and rapid manufacturing (RM) of implants, scaffolds, or organs. As an introduction to the problem, principles related to data acquisition, enhancement, segmentation, and interpolation are discussed. After this, some available three-dimensional medical reconstruction software tools are presented. Finally, applications of these technologies are illustrated.
The Three Dimensional Numerical Simulation of Vertical Jet in Waves
NASA Astrophysics Data System (ADS)
Yuan, L. R.
A three dimensional numerical model of vertical turbulent jet in waves is established by using the nonlinear k - ɛ turbulence model with VOF method. And a lot of numerical experiments with different wave parameters are carried out. Based on the numerical experiments results, the paper put emphases upon the analysis of the relations between the distributions of the pollutant concentration and water waves’ parameters in the jet initial entrainment.
Three-dimensional massive gravity and the bigravity black hole
NASA Astrophysics Data System (ADS)
Bañados, Máximo; Theisen, Stefan
2009-11-01
We study three-dimensional massive gravity formulated as a theory with two dynamical metrics, like the f-g theories of Isham-Salam and Strathdee. The action is parity preserving and has no higher derivative terms. The spectrum contains a single massive graviton. This theory has several features discussed recently in TMG and NMG. We find warped black holes, a critical point, and generalized Brown-Henneaux boundary conditions.