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Sample records for cellular resolution volumetric

  1. Transcutical imaging with cellular and subcellular resolution.

    PubMed

    Tao, Xiaodong; Lin, Hui-Hao; Lam, Tuwin; Rodriguez, Ramiro; Wang, Jing W; Kubby, Joel

    2017-03-01

    We demonstrate transcutical structural and functional imaging of neurons labeled with genetically encoded red fluorescent proteins and calcium indicators in the living Drosophila brain with cellular and subcellular resolution.

  2. Transcutical imaging with cellular and subcellular resolution

    PubMed Central

    Tao, Xiaodong; Lin, Hui-Hao; Lam, Tuwin; Rodriguez, Ramiro; Wang, Jing W.; Kubby, Joel

    2017-01-01

    We demonstrate transcutical structural and functional imaging of neurons labeled with genetically encoded red fluorescent proteins and calcium indicators in the living Drosophila brain with cellular and subcellular resolution. PMID:28663828

  3. New Approaches in Renal Microscopy: Volumetric Imaging and Super-resolution Microscopy

    PubMed Central

    Kim, Alfred H.J.; Suleiman, Hani; Shaw, Andrey S.

    2016-01-01

    Purpose of review Histologic and electron microscopic analysis of the kidney has provided tremendous insight into structures such as the glomerulus and nephron. Recent advances in imaging, such as deep volumetric approaches and super-resolution microscopy, have the capacity to dramatically enhance our current understanding of the structure and function of the kidney. Volumetric imaging can generate images millimeters below the surface of the intact kidney. Super-resolution microscopy breaks the diffraction barrier inherent in traditional light microscopy, enabling for the visualization of fine structures. Here, we describe new approaches to deep volumetric and super-resolution microscopy of the kidney. Recent findings Rapid advances in lasers, microscopic objectives, and tissue preparation have transformed our ability to deep volumetric image the kidney. Innovations in sample preparation have allowed for super-resolution imaging with electron microscopy correlation, providing unprecedented insight into the structures within the glomerulus. Summary Technological advances in imaging have revolutionized our capacity to image both large volumes of tissue and the finest structural details of a cell. These new advances have the potential to provide additional profound observations into the normal and pathologic functions of the kidney. PMID:27023834

  4. Optical reconstruction of murine colorectal mucosa at cellular resolution

    PubMed Central

    Liu, Cambrian Y.; Dubé, Philip E.; Girish, Nandini; Reddy, Ajay T.

    2015-01-01

    The mucosal layer of the colon is a unique and dynamic site where host cells interface with one another and the microbiome, with major implications for physiology and disease. However, the cellular mechanisms mediating colonic regeneration, inflammation, dysplasia, and dysbiosis remain undercharacterized, partly because the use of thin tissue sections in many studies removes important volumetric context. To address these challenges in visualization, we have developed the deep mucosal imaging (DMI) method to reconstruct continuous extended volumes of mouse colorectal mucosa at cellular resolution. Use of ScaleA2 and SeeDB clearing agents enabled full visualization of the colonic crypt, the fundamental unit of adult colon. Confocal imaging of large colorectal expanses revealed epithelial structures involved in repair, inflammation, tumorigenesis, and stem cell function, in fluorescent protein-labeled, immunostained, paraffin-embedded, or human biopsy samples. We provide freely available software to reconstruct and explore on computers with standard memory allocations the large DMI datasets containing in toto representations of distal colonic mucosal volume. Extended-volume imaging of colonic mucosa through the novel, extensible, and readily adopted DMI approach will expedite mechanistic investigations of intestinal physiology and pathophysiology at intracrypt to multicrypt length scales. PMID:25721303

  5. Video-rate volumetric functional imaging of the brain at synaptic resolution

    PubMed Central

    Lu, Rongwen; Sun, Wenzhi; Liang, Yajie; Kerlin, Aaron; Bierfeld, Jens; Seelig, Johannes; Wilson, Daniel E.; Scholl, Benjamin; Mohar, Boaz; Tanimoto, Masashi; Koyama, Minoru; Fitzpatrick, David; Orger, Michael B.; Ji, Na

    2017-01-01

    Neurons and neural networks often extend hundreds to thousands of micrometers in three dimensions. To capture all the calcium transients associated with their activity, we need volume imaging methods with sub-second temporal resolution. Such speed is challenging for conventional two-photon laser scanning microscopy (2PLSM) to achieve, because of its dependence on serial focal scanning in 3D and the limited brightness of indicators. Here we present an optical module that can be easily integrated into standard 2PLSMs to generate an axially elongated Bessel focus. Scanning the Bessel focus in 2D turned frame rate into volume rate and enabled video-rate volumetric imaging. Using Bessel foci designed to maintain lateral resolution that resolves synapses in sparsely labeled brains in vivo, we demonstrated the power of this approach in enabling discoveries for neurobiology by imaging the calcium dynamics of volumes of neurons and synapses in fruit flies, zebrafish larvae, mice, and ferrets in vivo. PMID:28250408

  6. 3D surface reconstruction and visualization of the Drosophila wing imaginal disc at cellular resolution

    NASA Astrophysics Data System (ADS)

    Bai, Linge; Widmann, Thomas; Jülicher, Frank; Dahmann, Christian; Breen, David

    2013-01-01

    Quantifying and visualizing the shape of developing biological tissues provide information about the morphogenetic processes in multicellular organisms. The size and shape of biological tissues depend on the number, size, shape, and arrangement of the constituting cells. To better understand the mechanisms that guide tissues into their final shape, it is important to investigate the cellular arrangement within tissues. Here we present a data processing pipeline to generate 3D volumetric surface models of epithelial tissues, as well as geometric descriptions of the tissues' apical cell cross-sections. The data processing pipeline includes image acquisition, editing, processing and analysis, 2D cell mesh generation, 3D contourbased surface reconstruction, cell mesh projection, followed by geometric calculations and color-based visualization of morphological parameters. In their first utilization we have applied these procedures to construct a 3D volumetric surface model at cellular resolution of the wing imaginal disc of Drosophila melanogaster. The ultimate goal of the reported effort is to produce tools for the creation of detailed 3D geometric models of the individual cells in epithelial tissues. To date, 3D volumetric surface models of the whole wing imaginal disc have been created, and the apicolateral cell boundaries have been identified, allowing for the calculation and visualization of cell parameters, e.g. apical cross-sectional area of cells. The calculation and visualization of morphological parameters show position-dependent patterns of cell shape in the wing imaginal disc. Our procedures should offer a general data processing pipeline for the construction of 3D volumetric surface models of a wide variety of epithelial tissues.

  7. In vivo volumetric imaging of the human upper eyelid with ultrahigh-resolution optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Bizheva, Kostadinka; Lee, Patrick; Sorbara, Luigina; Hutchings, Natalie; Simpson, Trefford

    2010-07-01

    The upper eyelid is a biological tissue with complex structure, essential for the maintenance of an optically clear ocular surface due to its physical (blinking) effect. The Meibomian glands (MGs) are structures that lie beneath the surface of the inner eyelid and are partially responsible for the production of the superficial oily layer of the tear film. The MGs are only superficially visible under magnification when the eyelid is everted. We present for the first time in vivo 3-D images of healthy and inflamed human MGs. Tomograms were acquired from the tarsal plate of everted human eyelids with a 1060-nm ultrahigh-resolution optical coherence tomography (UHOCT) system, with ~3 μm×10 μm (axial×lateral) resolution in biological tissue at the rate of 91,911 A-scans/s. Comparison with histology shows that the UHOCT images reveal a spatial distribution of structures that appear to correspond with the MGs' acini and ducts (in healthy subjects), and accumulation of heterogeneous, highly scattering biological material and clear fluids in the visibly blocked glands. Noninvasive, volumetric high-resolution morphological imaging of the human tarsal area could have a significant impact in the clinical diagnosis of inflammatory and noninflammatory lid pathologies.

  8. Protocol for volumetric segmentation of medial temporal structures using high-resolution 3-D magnetic resonance imaging.

    PubMed

    Bonilha, Leonardo; Kobayashi, Eliane; Cendes, Fernando; Min Li, Li

    2004-06-01

    Quantitative analysis of brain structures in normal subjects and in different neurological conditions can be carried out in vivo through magnetic resonance imaging (MRI) volumetric studies. The use of high-resolution MRI combined with image post-processing that allows simultaneous multiplanar view may facilitate volumetric segmentation of temporal lobe structures. We define a protocol for volumetric studies of medial temporal lobe structures using high-resolution MR images and we studied 30 healthy subjects (19 women; mean age, 33 years; age range, 21-55 years). Images underwent field non-homogeneity correction and linear stereotaxic transformation into a standard space. Structures of interest comprised temporopolar, entorhinal, perirhinal, parahippocampal cortices, hippocampus, and the amygdala. Segmentation was carried out with multiplanar assessment. There was no statistically significant left/right-sided asymmetry concerning any structure analyzed. Neither gender nor age influenced the volumes obtained. The coefficient of repeatability showed no significant difference of intra- and interobserver measurements. Imaging post-processing and simultaneous multiplanar view of high-resolution MRI facilitates volumetric assessment of the medial portion of the temporal lobe with strict adherence to anatomic landmarks. This protocol shows no significant inter- and intraobserver variations and thus is reliable for longitudinal studies.

  9. Mapping brain structure and function: cellular resolution, global perspective.

    PubMed

    Zupanc, Günther K H

    2017-04-01

    A comprehensive understanding of the brain requires analysis, although from a global perspective, with cellular, and even subcellular, resolution. An important step towards this goal involves the establishment of three-dimensional high-resolution brain maps, incorporating brain-wide information about the cells and their connections, as well as the chemical architecture. The progress made in such anatomical brain mapping in recent years has been paralleled by the development of physiological techniques that enable investigators to generate global neural activity maps, also with cellular resolution, while simultaneously recording the organism's behavioral activity. Combination of the high-resolution anatomical and physiological maps, followed by theoretical systems analysis of the deduced network, will offer unprecedented opportunities for a better understanding of how the brain, as a whole, processes sensory information and generates behavior.

  10. Automated volumetric segmentation method for growth consistency of nonsolid pulmonary nodules in high-resolution CT

    NASA Astrophysics Data System (ADS)

    Browder, William A.; Reeves, Anthony P.; Apananosovich, Tatiyana V.; Cham, Matthew D.; Yankelevitz, David F.; Henschke, Claudia I.

    2007-03-01

    There is widespread clinical interest in the study of pulmonary nodules for early diagnosis of lung cancer. These nodules can be broadly classified into one of three types, solid, nonsolid and part-solid. Solid nodules have been extensively studied, while little research has focused on the characterization of nonsolid and part-solid nodules. Nonsolid nodules have an appearance in high-resolution CT consisting of voxels only slightly more dense than that of the surrounding lung parenchyma. For the solid nodule, robust techniques are available to estimate growth rate and this is commonly used to distinguish benign from malignant. For the nonsolid types, these techniques are less well developed. In this research, we propose an automated volumetric segmentation method for nonsolid nodules that accurately determines a nonsolid nodule's growth rate. Our method starts with an initial noise-filtering stage in the parenchyma region. Each voxel is then classified into one of three tissue types; lung parenchyma, nonsolid and solid. Removal of vessel attachments to the lesion is achieved with the use of a filter that focuses on vessel characteristics. Our results indicate that the automated method is more consistent than the radiologist with a median growth consistency of 1.87 compared to 3.12 for the radiologist on a database of 25 cases.

  11. Volumetric limiting spatial resolution analysis of four dimensional digital subtraction angiography (4D-DSA)

    NASA Astrophysics Data System (ADS)

    Davis, Brian; Oberstar, Erick; Royalty, Kevin; Schafer, Sebastian; Strother, Charles; Mistretta, Charles

    2015-03-01

    Static C-Arm CT 3D FDK baseline reconstructions (3D-DSA) are unable to provide temporal information to radiologists. 4D-DSA provides a time series of 3D volumes implementing a constrained image, thresholded 3D-DSA, reconstruction utilizing temporal dynamics in the 2D projections. Volumetric limiting spatial resolution (VLSR) of 4DDSA is quantified and compared to a 3D-DSA reconstruction using the same 3D-DSA parameters. Investigated were the effects of varying over significant ranges the 4D-DSA parameters of 2D blurring kernel size applied to the projection and threshold applied to the 3D-DSA when generating the constraining image of a scanned phantom (SPH) and an electronic phantom (EPH). The SPH consisted of a 76 micron tungsten wire encased in a 47 mm O.D. plastic radially concentric thin walled support structure. An 8-second/248-frame/198° scan protocol acquired the raw projection data. VLSR was determined from averaged MTF curves generated from each 2D transverse slice of every (248) 4D temporal frame (3D). 4D results for SPH and EPH were compared to the 3D-DSA. Analysis of the 3D-DSA resulted in a VLSR of 2.28 and 1.69 lp/mm for the EPH and SPH respectively. Kernel (2D) sizes of either 10x10 or 20x20 pixels with a threshold of 10% of the 3D-DSA as a constraining image provided 4D-DSA VLSR nearest to the 3D-DSA. 4D-DSA algorithms yielded 2.21 and 1.67 lp/mm with a percent error of 3.1% and 1.2% for the EPH and SPH respectively as compared to the 3D-DSA. This research indicates 4D-DSA is capable of retaining the resolution of the 3D-DSA.

  12. Whole-brain calcium imaging with cellular resolution in freely behaving Caenorhabditis elegans.

    PubMed

    Nguyen, Jeffrey P; Shipley, Frederick B; Linder, Ashley N; Plummer, George S; Liu, Mochi; Setru, Sagar U; Shaevitz, Joshua W; Leifer, Andrew M

    2016-02-23

    The ability to acquire large-scale recordings of neuronal activity in awake and unrestrained animals is needed to provide new insights into how populations of neurons generate animal behavior. We present an instrument capable of recording intracellular calcium transients from the majority of neurons in the head of a freely behaving Caenorhabditis elegans with cellular resolution while simultaneously recording the animal's position, posture, and locomotion. This instrument provides whole-brain imaging with cellular resolution in an unrestrained and behaving animal. We use spinning-disk confocal microscopy to capture 3D volumetric fluorescent images of neurons expressing the calcium indicator GCaMP6s at 6 head-volumes/s. A suite of three cameras monitor neuronal fluorescence and the animal's position and orientation. Custom software tracks the 3D position of the animal's head in real time and two feedback loops adjust a motorized stage and objective to keep the animal's head within the field of view as the animal roams freely. We observe calcium transients from up to 77 neurons for over 4 min and correlate this activity with the animal's behavior. We characterize noise in the system due to animal motion and show that, across worms, multiple neurons show significant correlations with modes of behavior corresponding to forward, backward, and turning locomotion.

  13. Multiplexed Intact-Tissue Transcriptional Analysis at Cellular Resolution.

    PubMed

    Sylwestrak, Emily Lauren; Rajasethupathy, Priyamvada; Wright, Matthew Arnot; Jaffe, Anna; Deisseroth, Karl

    2016-02-11

    In recently developed approaches for high-resolution imaging within intact tissue, molecular characterization over large volumes has been largely restricted to labeling of proteins. But volumetric nucleic acid labeling may represent a far greater scientific and clinical opportunity, enabling detection of not only diverse coding RNA variants but also non-coding RNAs. Moreover, scaling immunohistochemical detection to large tissue volumes has limitations due to high cost, limited renewability/availability, and restricted multiplexing capability of antibody labels. With the goal of versatile, high-content, and scalable molecular phenotyping of intact tissues, we developed a method using carbodiimide-based chemistry to stably retain RNAs in clarified tissue, coupled with amplification tools for multiplexed detection. The resulting technology enables robust measurement of activity-dependent transcriptional signatures, cell-identity markers, and diverse non-coding RNAs in rodent and human tissue volumes. The growing set of validated probes is deposited in an online resource for nucleating related developments from across the scientific community.

  14. Cellular-resolution connectomics: challenges of dense neural circuit reconstruction.

    PubMed

    Helmstaedter, Moritz

    2013-06-01

    Neuronal networks are high-dimensional graphs that are packed into three-dimensional nervous tissue at extremely high density. Comprehensively mapping these networks is therefore a major challenge. Although recent developments in volume electron microscopy imaging have made data acquisition feasible for circuits comprising a few hundreds to a few thousands of neurons, data analysis is massively lagging behind. The aim of this perspective is to summarize and quantify the challenges for data analysis in cellular-resolution connectomics and describe current solutions involving online crowd-sourcing and machine-learning approaches.

  15. Comprehensive cellular-resolution atlas of the adult human brain.

    PubMed

    Ding, Song-Lin; Royall, Joshua J; Sunkin, Susan M; Ng, Lydia; Facer, Benjamin A C; Lesnar, Phil; Guillozet-Bongaarts, Angie; McMurray, Bergen; Szafer, Aaron; Dolbeare, Tim A; Stevens, Allison; Tirrell, Lee; Benner, Thomas; Caldejon, Shiella; Dalley, Rachel A; Dee, Nick; Lau, Christopher; Nyhus, Julie; Reding, Melissa; Riley, Zackery L; Sandman, David; Shen, Elaine; van der Kouwe, Andre; Varjabedian, Ani; Write, Michelle; Zollei, Lilla; Dang, Chinh; Knowles, James A; Koch, Christof; Phillips, John W; Sestan, Nenad; Wohnoutka, Paul; Zielke, H Ronald; Hohmann, John G; Jones, Allan R; Bernard, Amy; Hawrylycz, Michael J; Hof, Patrick R; Fischl, Bruce; Lein, Ed S

    2016-11-01

    Detailed anatomical understanding of the human brain is essential for unraveling its functional architecture, yet current reference atlases have major limitations such as lack of whole-brain coverage, relatively low image resolution, and sparse structural annotation. We present the first digital human brain atlas to incorporate neuroimaging, high-resolution histology, and chemoarchitecture across a complete adult female brain, consisting of magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI), and 1,356 large-format cellular resolution (1 µm/pixel) Nissl and immunohistochemistry anatomical plates. The atlas is comprehensively annotated for 862 structures, including 117 white matter tracts and several novel cyto- and chemoarchitecturally defined structures, and these annotations were transferred onto the matching MRI dataset. Neocortical delineations were done for sulci, gyri, and modified Brodmann areas to link macroscopic anatomical and microscopic cytoarchitectural parcellations. Correlated neuroimaging and histological structural delineation allowed fine feature identification in MRI data and subsequent structural identification in MRI data from other brains. This interactive online digital atlas is integrated with existing Allen Institute for Brain Science gene expression atlases and is publicly accessible as a resource for the neuroscience community. J. Comp. Neurol. 524:3127-3481, 2016. © 2016 The Authors The Journal of Comparative Neurology Published by Wiley Periodicals, Inc. Copyright © 2016 The Authors The Journal of Comparative Neurology Published by Wiley Periodicals, Inc.

  16. Sparse representation-based volumetric super-resolution algorithm for 3D CT images of reservoir rocks

    NASA Astrophysics Data System (ADS)

    Li, Zhengji; Teng, Qizhi; He, Xiaohai; Yue, Guihua; Wang, Zhengyong

    2017-09-01

    The parameter evaluation of reservoir rocks can help us to identify components and calculate the permeability and other parameters, and it plays an important role in the petroleum industry. Until now, computed tomography (CT) has remained an irreplaceable way to acquire the microstructure of reservoir rocks. During the evaluation and analysis, large samples and high-resolution images are required in order to obtain accurate results. Owing to the inherent limitations of CT, however, a large field of view results in low-resolution images, and high-resolution images entail a smaller field of view. Our method is a promising solution to these data collection limitations. In this study, a framework for sparse representation-based 3D volumetric super-resolution is proposed to enhance the resolution of 3D voxel images of reservoirs scanned with CT. A single reservoir structure and its downgraded model are divided into a large number of 3D cubes of voxel pairs and these cube pairs are used to calculate two overcomplete dictionaries and the sparse-representation coefficients in order to estimate the high frequency component. Future more, to better result, a new feature extract method with combine BM4D together with Laplacian filter are introduced. In addition, we conducted a visual evaluation of the method, and used the PSNR and FSIM to evaluate it qualitatively.

  17. Resolution scalable image coding with reversible cellular automata.

    PubMed

    Cappellari, Lorenzo; Milani, Simone; Cruz-Reyes, Carlos; Calvagno, Giancarlo

    2011-05-01

    In a resolution scalable image coding algorithm, a multiresolution representation of the data is often obtained using a linear filter bank. Reversible cellular automata have been recently proposed as simpler, nonlinear filter banks that produce a similar representation. The original image is decomposed into four subbands, such that one of them retains most of the features of the original image at a reduced scale. In this paper, we discuss the utilization of reversible cellular automata and arithmetic coding for scalable compression of binary and grayscale images. In the binary case, the proposed algorithm that uses simple local rules compares well with the JBIG compression standard, in particular for images where the foreground is made of a simple connected region. For complex images, more efficient local rules based upon the lifting principle have been designed. They provide compression performances very close to or even better than JBIG, depending upon the image characteristics. In the grayscale case, and in particular for smooth images such as depth maps, the proposed algorithm outperforms both the JBIG and the JPEG2000 standards under most coding conditions.

  18. Automated Classification of Usual Interstitial Pneumonia using Regional Volumetric Texture Analysis in High-Resolution CT

    PubMed Central

    Depeursinge, Adrien; Chin, Anne S.; Leung, Ann N.; Terrone, Donato; Bristow, Michael; Rosen, Glenn; Rubin, Daniel L.

    2014-01-01

    Objectives We propose a novel computational approach for the automated classification of classic versus atypical usual interstitial pneumonia (UIP). Materials and Methods 33 patients with UIP were enrolled in this study. They were classified as classic versus atypical UIP by a consensus of two thoracic radiologists with more than 15 years of experience using the American Thoracic Society evidence–based guidelines for CT diagnosis of UIP. Two cardiothoracic fellows with one year of subspecialty training provided independent readings. The system is based on regional characterization of the morphological tissue properties of lung using volumetric texture analysis of multiple detector CT images. A simple digital atlas with 36 lung subregions is used to locate texture properties, from which the responses of multi-directional Riesz wavelets are obtained. Machine learning is used to aggregate and to map the regional texture attributes to a simple score that can be used to stratify patients with UIP into classic and atypical subtypes. Results We compared the predictions based on regional volumetric texture analysis with the ground truth established by expert consensus. The area under the receiver operating characteristic curve of the proposed score was estimated to be 0.81 using a leave-one-patient-out cross-validation, with high specificity for classic UIP. The performance of our automated method was found to be similar to that of the two fellows and to the agreement between experienced chest radiologists reported in the literature. However, the errors of our method and the fellows occurred on different cases, which suggests that combining human and computerized evaluations may be synergistic. Conclusions Our results are encouraging and suggest that an automated system may be useful in routine clinical practice as a diagnostic aid for identifying patients with complex lung disease such as classic UIP, obviating the need for invasive surgical lung biopsy and its

  19. Whole-brain calcium imaging with cellular resolution in freely behaving Caenorhabditis elegans

    NASA Astrophysics Data System (ADS)

    Nguyen, Jeffrey; Shipley, Frederick; Linder, Ashley; Plummer, George; Liu, Mochi; Setru, Sagar; Shaevitz, Joshua; Leifer, Andrew

    The ability to acquire large-scale recordings of neuronal activity in awake and unrestrained animals is needed to provide new insights into how populations of neurons generate animal behavior. Acquiring this data, however, is challenging because it is difficult to track and image individual neurons as an animal deforms its posture and moves many body lengths. Here, we present an instrument capable of recording intracellular calcium transients from the majority of neurons in the head of a freely behaving Caenorhabditis elegans with cellular resolution while simultaneously recording the animal's position, posture, and locomotion. 3D volumetric fluorescent images of neurons expressing the calcium indicator GCaMP6s are recorded at 6 head-volumes/s using spinning disk confocal microscopy. At the same time, we record low magnification images of the animal to measure the animals behavior and track its head as it moves. We develop a time independent neuronal matching algorithm that uses non-rigid point set registration and machine learning to correctly match neurons across time. Using this method, we are able to observe calcium transients from up to 90 neurons for over 4 min and correlate the neural activity with the animal's behavior.

  20. Determining Metacarpophalangeal Flexion Angle Tolerance for Reliable Volumetric Joint Space Measurements by High-resolution Peripheral Quantitative Computed Tomography.

    PubMed

    Tom, Stephanie; Frayne, Mark; Manske, Sarah L; Burghardt, Andrew J; Stok, Kathryn S; Boyd, Steven K; Barnabe, Cheryl

    2016-10-01

    The position-dependence of a method to measure the joint space of metacarpophalangeal (MCP) joints using high-resolution peripheral quantitative computed tomography (HR-pQCT) was studied. Cadaveric MCP were imaged at 7 flexion angles between 0 and 30 degrees. The variability in reproducibility for mean, minimum, and maximum joint space widths and volume measurements was calculated for increasing degrees of flexion. Root mean square coefficient of variance values were < 5% under 20 degrees of flexion for mean, maximum, and volumetric joint spaces. Values for minimum joint space width were optimized under 10 degrees of flexion. MCP joint space measurements should be acquired at < 10 degrees of flexion in longitudinal studies.

  1. Noninvasive volumetric imaging and morphometry of the rodent retina with high-speed, ultrahigh-resolution optical coherence tomography.

    PubMed

    Srinivasan, Vivek J; Ko, Tony H; Wojtkowski, Maciej; Carvalho, Mariana; Clermont, Allen; Bursell, Sven-Erik; Song, Qin Hui; Lem, Janis; Duker, Jay S; Schuman, Joel S; Fujimoto, James G

    2006-12-01

    To demonstrate high-speed, ultrahigh-resolution optical coherence tomography (OCT) for noninvasive, in vivo, three-dimensional imaging of the retina in rat and mouse models. A high-speed, ultrahigh-resolution OCT system using spectral, or Fourier domain, detection has been developed for small animal retinal imaging. Imaging is performed with a contact lens and postobjective scanning. An axial image resolution of 2.8 mum is achieved with a spectrally broadband superluminescent diode light source with a bandwidth of approximately 150 nm at approximately 900-nm center wavelength. Imaging can be performed at 24,000 axial scans per second, which is approximately 100 times faster than previous ultrahigh-resolution OCT systems. High-definition and three-dimensional retinal imaging is performed in vivo in mouse and rat models. High-speed, ultrahigh-resolution OCT enabled high-definition, high transverse pixel density imaging of the murine retina and visualization of all major intraretinal layers. Raster scan protocols enabled three-dimensional volumetric imagingand comprehensive retinal segmentation algorithms allowed measurement of retinal layers. An OCT fundus image, akin to a fundus photograph was generated by axial summation of three-dimensional OCT data, thus enabling precise registration of OCT measurements to retinal fundus features. High-speed, ultrahigh-resolution OCT enables imaging of retinal architectural morphology in small animal models. OCT fundus images allow precise registration of OCT images and repeated measurements with respect to retinal fundus features. Three-dimensional OCT imaging enables visualization and quantification of retinal structure, which promises to allow repeated, noninvasive measurements to track disease progression, thereby reducing the need for killing the animal for histology. This capability can accelerate basic research studies in rats and mice and their translation into clinical patient care.

  2. Microscopic high-resolution digital volumetric imaging of human hair fibers.

    PubMed

    Gruber, J V; Kerschman, R

    2004-01-01

    Methods for examining cationic polymer deposition on hair are well known and polymers such as Polyquaternium-10 have enjoyed a significant commercial impact on shampoos and body washes as unique conditioning materials. It was recently reported that hair can be examined using a new microscopic called Digital Volumetric Imaging or DVI (10). By employing fluorescent dyes, deposition of cationic oligosaccharides onto damaged blond hair fibers was discussed. Because hair auto-fluorescences, the microscope allows for examination of hair fibers directly including viewing of the cuticle, cortex and melanin within the cortex and careful imaging even distinguishes the medulla of the hair fiber. In this paper, examination of six virgin hair types including: 1) Afro-American, 2) Asian, 3) European brown, 4) red, 5) blond and 6) gray was conducted looking for differences that each hair type brings to the visualizing technique. Digital manipulation of the fluorescent data allows for examination of interior hair fiber structures as well as the development of animated movies of three dimensional hair fiber structures.

  3. Assessment of volumetric noise and resolution performance for linear and nonlinear CT reconstruction methods

    SciTech Connect

    Chen, Baiyu; Christianson, Olav; Wilson, Joshua M.; Samei, Ehsan

    2014-07-15

    Purpose: For nonlinear iterative image reconstructions (IR), the computed tomography (CT) noise and resolution properties can depend on the specific imaging conditions, such as lesion contrast and image noise level. Therefore, it is imperative to develop a reliable method to measure the noise and resolution properties under clinically relevant conditions. This study aimed to develop a robust methodology to measure the three-dimensional CT noise and resolution properties under such conditions and to provide guidelines to achieve desirable levels of accuracy and precision. Methods: The methodology was developed based on a previously reported CT image quality phantom. In this methodology, CT noise properties are measured in the uniform region of the phantom in terms of a task-based 3D noise-power spectrum (NPS{sub task}). The in-plane resolution properties are measured in terms of the task transfer function (TTF) by applying a radial edge technique to the rod inserts in the phantom. The z-direction resolution properties are measured from a supplemental phantom, also in terms of the TTF. To account for the possible nonlinearity of IR, the NPS{sub task} is measured with respect to the noise magnitude, and the TTF with respect to noise magnitude and edge contrast. To determine the accuracy and precision of the methodology, images of known noise and resolution properties were simulated. The NPS{sub task} and TTF were measured on the simulated images and compared to the truth, with criteria established to achieve NPS{sub task} and TTF measurements with <10% error. To demonstrate the utility of this methodology, measurements were performed on a commercial CT system using five dose levels, two slice thicknesses, and three reconstruction algorithms (filtered backprojection, FBP; iterative reconstruction in imaging space, IRIS; and sinogram affirmed iterative reconstruction with strengths of 5, SAFIRE5). Results: To achieve NPS{sub task} measurements with <10% error, the

  4. Accuracy and Resolution of In Vitro Imaging Based Porcine Lens Volumetric Measurements

    PubMed Central

    Wendt, Mark; Bockhorst, Kurt; He, Lin; Glasser, Adrian

    2013-01-01

    There is considerable interest in determining lens volume in the living eye. Lens volume is of interest to understand accommodative changes in the lens and to size accommodative IOLs (A-IOLs) to fit the capsular bag. Some studies have suggested lens volume change during accommodation. Magnetic Resonance Imaging (MRI) is the only method available to determine lens volume in vivo. MRI is, by its nature, relatively low in temporal and spatial resolution. Therefore analysis often requires determining lens volume from single image slices with relatively low resolution on which only simple image analysis methods can be used and without repeated measures. In this study, 7T MRI scans encompassing the full lens volume were performed on 19 enucleated pig eyes. The eyes were then dissected to isolate and photograph the lens in profile and the lens volumes were measured empirically using a fluid displacement method. Lens volumes were calculated from two- and three-dimensional (2D & 3D) MR and 2D photographic profile images of the isolated lenses using several different analysis methods. Image based and actual measured lens volumes were compared. The average image-based volume of all lenses varied from the average measured volume of all lenses by 0.6% to 6.4% depending on the image analysis method. Image analysis methods that use gradient based edge detection showed higher precision with actual volumes (r2: 0.957 to 0.990), while threshold based segmentation had poorer correlations (r2: 0.759 to 0.828). The root-mean-square (RMS) difference between image analysis based volumes and fluid displacement measured volumes ranged from 8.51 µl to 25.79 µl. This provides an estimate of the error of previously published methods used to calculate lens volume. Immobilized, enucleated porcine eyes permit improved MR image resolution relative to living eyes and therefore improved image analysis methods to calculate lens volume. The results show that some of the accommodative changes in

  5. A flexible and accurate digital volume correlation method applicable to high-resolution volumetric images

    NASA Astrophysics Data System (ADS)

    Pan, Bing; Wang, Bo

    2017-10-01

    Digital volume correlation (DVC) is a powerful technique for quantifying interior deformation within solid opaque materials and biological tissues. In the last two decades, great efforts have been made to improve the accuracy and efficiency of the DVC algorithm. However, there is still a lack of a flexible, robust and accurate version that can be efficiently implemented in personal computers with limited RAM. This paper proposes an advanced DVC method that can realize accurate full-field internal deformation measurement applicable to high-resolution volume images with up to billions of voxels. Specifically, a novel layer-wise reliability-guided displacement tracking strategy combined with dynamic data management is presented to guide the DVC computation from slice to slice. The displacements at specified calculation points in each layer are computed using the advanced 3D inverse-compositional Gauss–Newton algorithm with the complete initial guess of the deformation vector accurately predicted from the computed calculation points. Since only limited slices of interest in the reference and deformed volume images rather than the whole volume images are required, the DVC calculation can thus be efficiently implemented on personal computers. The flexibility, accuracy and efficiency of the presented DVC approach are demonstrated by analyzing computer-simulated and experimentally obtained high-resolution volume images.

  6. Volumetric Doppler angle correction for ultrahigh-resolution optical coherence Doppler tomography

    NASA Astrophysics Data System (ADS)

    You, Jiang; Li, Ang; Du, Congwu; Pan, Yingtian

    2017-01-01

    Ultrahigh-resolution optical coherence Doppler tomography (μODT) demonstrates great potential for quantitative blood flow imaging owing to its large field of view and capillary resolution. However, μODT only detects the axial flow velocity and requires Doppler angle correction to retrieve the absolute velocity. Although methods for Doppler angle tracking of single or few large vessels have been reported, a method that enables angle correction of the entire 3D microvascular networks remains a challenge. Here, we present a method based on eigenvalue analysis of 3D Hessian matrix to retrieve the orientation of each tubular vessel. As the algorithm is voxel based, it is suitable for effective tracking of Doppler angle matrix and restoring the absolute flow over the 3D vascular flow networks. We present results on simulation and flow phantom studies to show its efficacy for accurate 3D angle tracking and absolute flow correction. Then, we perform an in vivo validation study on mouse micro-circulatory cerebral blood flow (CBF) networks, which clearly demonstrates the capability of this method for tracking the Doppler angle matrix of the highly complex 3D CBF networks.

  7. Video-rate volumetric functional imaging of the brain at synaptic resolution.

    PubMed

    Lu, Rongwen; Sun, Wenzhi; Liang, Yajie; Kerlin, Aaron; Bierfeld, Jens; Seelig, Johannes D; Wilson, Daniel E; Scholl, Benjamin; Mohar, Boaz; Tanimoto, Masashi; Koyama, Minoru; Fitzpatrick, David; Orger, Michael B; Ji, Na

    2017-04-01

    Neurons and neural networks often extend hundreds of micrometers in three dimensions. Capturing the calcium transients associated with their activity requires volume imaging methods with subsecond temporal resolution. Such speed is a challenge for conventional two-photon laser-scanning microscopy, because it depends on serial focal scanning in 3D and indicators with limited brightness. Here we present an optical module that is easily integrated into standard two-photon laser-scanning microscopes to generate an axially elongated Bessel focus, which when scanned in 2D turns frame rate into volume rate. We demonstrated the power of this approach in enabling discoveries for neurobiology by imaging the calcium dynamics of volumes of neurons and synapses in fruit flies, zebrafish larvae, mice and ferrets in vivo. Calcium signals in objects as small as dendritic spines could be resolved at video rates, provided that the samples were sparsely labeled to limit overlap in their axially projected images.

  8. Quantification of external root resorption by low- vs high-resolution cone-beam computed tomography and periapical radiography: A volumetric and linear analysis.

    PubMed

    Ponder, Stacy N; Benavides, Erika; Kapila, Sunil; Hatch, Nan E

    2013-01-01

    The goal of this study was to determine whether cone beam-computed tomography (CBCT) images with resolutions similar to those produced in orthodontic offices have sufficient resolution to accurately quantify root resorption defects. Teeth containing simulated root defects were scanned by microcomputed tomography (microCT) and CBCT at 0.2- and 0.4-mm resolutions and were radiographed by the periapical technique. Root length was measured with digital calipers. Comparisons were made to establish significance between imagining modalities and to compare defects of differing severity and position. The mean absolute difference in volumetric measurements of lateral defects from 0.2-mm-resolution CBCT images compared with those from microCT images was significantly smaller than those from 0.4-mm-resolution CBCT images (0.20 ± 0.2 mm(3) vs 0.30 ± 0.3 mm(3); P = 0.002). A Bland-Altman analysis showed that the 95% limits of agreement range between low-resolution CBCT and microCT volumetric measurements was1.44-fold greater than that between high-resolution CBCT and microCT measurements (-0.87-0.68 vs -0.49-0.59 mm(3)). The accuracy of the volumetric measurements was also significantly influenced by defect size (P = 0.004 for high-resolution CBCT, P = 0.005 for low-resolution CBCT) and, on low-resolution scans, by the defect's vertical position (P = 0.012). Linear measurements of apical defects from both the 0.2- and 0.4-mm-resolution CBCT images were significantly more similar to the measurements made with digital calipers than the measurements from the periapical radiographs (P <0.0001 and P <0.0001, respectively). Our results demonstrated that, compared with measurements from microCT images, high-resolution CBCT scans lead to more accurate volumetric quantifications of lateral resorption defects than do low-resolution scans. Both high- and low-resolution CBCT scans can also be used to more accurately measure external apical root resorption defects than periapical

  9. Precision of volumetric assessment of proximal femur microarchitecture from high-resolution 3T MRI.

    PubMed

    Hotca, Alexandra; Ravichandra, Shreyas; Mikheev, Artem; Rusinek, Henry; Chang, Gregory

    2015-01-01

    To evaluate the precision of measures of bone volume and bone volume fraction derived from high-resolution 3T MRI of proximal femur bone microarchitecture using non-uniformity correction. This HIPAA compliant, institutional review board approved study was conducted on six volunteers (mean age 56 ± 13 years), and written informed consent was obtained. All volunteers underwent a 3T FLASH MRI hip scan at three time points: baseline, second scan same day (intra-scans), and third scan one week later (inter-scans). Segmentation of femur images and values for total proximal femur volume (T), bone volume (B), and bone volume fraction (BVF) were calculated using in-house developed software, FireVoxel. Two types of non-uniformity corrections were applied to images (N3 and BiCal). Precision values were calculated using absolute percent error (APE). Statistical analysis was carried out using one-sample one-sided t test to observe the consistency of the precision and paired t test to compare between the various methods and scans. No significant differences in bone volume measurements were observed for intra- and inter-scans. When using non-uniformity correction and assessing all subjects uniformly at the level of the lesser trochanter, precision values overall improved, especially significantly (p < 0.05) when measuring bone volume, B . B values using the combination of N3 or BiCal with CLT had a significant consistent APE values of less than 2.5 %, while BVF values were all consistently and significantly lower than 2.5 % APE. Our results demonstrate the precision of high-resolution 3D MRI measures were comparable to that of dual-energy X-ray absorptiometry. Additional corrections to the analysis technique by cropping at the lesser trochanter or using non-uniformity corrections helped to improve precision. The high precision values from these MRI scans provide evidence for MRI of the proximal femur as a promising tool for osteoporosis diagnosis and treatment.

  10. Histomorphometric analysis of nuclear and cellular volumetric alterations in oral lichen planus, lichenoid lesions and normal oral mucosa using image analysis software.

    PubMed

    Venkatesiah, Sowmya S; Kale, Alka D; Hallikeremath, Seema R; Kotrashetti, Vijayalakshmi S

    2013-01-01

    Lichen planus is a chronic inflammatory mucocutaneous disease that clinically and histologically resembles lichenoid lesions, although the latter has a different etiology. Though criteria have been suggested for differentiating oral lichen planus from lichenoid lesions, confusion still prevails. To study the cellular and nuclear volumetric features in the epithelium of normal mucosa, lichen planus, and lichenoid lesions to determine variations if any. A retrospective study was done on 25 histologically diagnosed cases each of oral lichen planus, oral lichenoid lesions, and normal oral mucosa. Cellular and nuclear morphometric measurements were assessed on hematoxylin and eosin sections using image analysis software. Analysis of variance test (ANOVA) and Tukey's post-hoc test. The basal cells of oral lichen planus showed a significant increase in the mean nuclear and cellular areas, and in nuclear volume; there was a significant decrease in the nuclear-cytoplasmic ratio as compared to normal mucosa. The suprabasal cells showed a significant increase in nuclear and cellular areas, nuclear diameter, and nuclear and cellular volumes as compared to normal mucosa. The basal cells of oral lichenoid lesions showed significant difference in the mean cellular area and the mean nuclear-cytoplasmic ratio as compared to normal mucosa, whereas the suprabasal cells differed significantly from normal mucosa in the mean nuclear area and the nuclear and cellular volumes. Morphometry can differentiate lesions of oral lichen planus and oral lichenoid lesions from normal oral mucosa. Thus, morphometry may serve to discriminate between normal and premalignant lichen planus and lichenoid lesions. These lesions might have a high risk for malignant transformation and may behave in a similar manner with respect to malignant transformation.

  11. Localization-Based Super-Resolution Imaging of Cellular Structures

    PubMed Central

    Kanchanawong, Pakorn; Waterman, Clare M.

    2013-01-01

    Fluorescence microscopy allows direct visualization of fluorescently tagged proteins within cells. However, the spatial resolution of conventional fluorescence microscopes is limited by diffraction to ~250 nm, prompting the development of super-resolution microscopy which offers resolution approaching the scale of single proteins, i.e., ~20 nm. Here, we describe protocols for single molecule localization-based super-resolution imaging, using focal adhesion proteins as an example and employing either photoswitchable fluorophores or photoactivatable fluorescent proteins. These protocols should also be easily adaptable to imaging a broad array of macromolecular assemblies in cells whose components can be fluorescently tagged and assemble into high density structures. PMID:23868582

  12. Validation of the relative insensitivity of volumetric-modulated arc therapy (VMAT) plan quality to gantry space resolution.

    PubMed

    Murtaza, Ghulam; Cora, Stefania; Khan, Ehsan Ullah

    2017-07-01

    Volumetric-modulated arc therapy (VMAT) is an efficient form of radiotherapy used to deliver intensity-modulated radiotherapy beams. The aim of this study was to investigate the relative insensitivity of VMAT plan quality to gantry angle spacing (GS). Most previous VMAT planning and dosimetric work for GS resolution has been conducted for single arc VMAT. In this work, a quantitative comparison of dose-volume indices (DIs) was made for partial-, single- and double-arc VMAT plans optimized at 2°, 3° and 4° GS, representing a large variation in deliverable multileaf collimator segments. VMAT plans of six prostate cancer and six head-and-neck cancer patients were simulated for an Elekta SynergyS® Linac (Elekta Ltd, Crawley, UK), using the SmartArc™ module of Pinnacle³ TPS, (version 9.2, Philips Healthcare). All optimization techniques generated clinically acceptable VMAT plans, except for the single-arc for the head-and-neck cancer patients. Plan quality was assessed by comparing the DIs for the planning target volume, organs at risk and normal tissue. A GS of 2°, with finest resolution and consequently highest intensity modulation, was considered to be the reference, and this was compared with GS 3° and 4°. The differences between the majority of reference DIs and compared DIs were <2%. The metrics, such as treatment plan optimization time and pretreatment (phantom) dosimetric calculation time, supported the use of a GS of 4°. The ArcCHECK™ phantom-measured dosimetric agreement verifications resulted in a >95.0% passing rate, using the criteria for γ (3%, 3 mm). In conclusion, a GS of 4° is an optimal choice for minimal usage of planning resources without compromise of plan quality. © The Author 2016. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

  13. Cardiac imaging with multi-sector data acquisition in volumetric CT: variation of effective temporal resolution and its potential clinical consequences

    NASA Astrophysics Data System (ADS)

    Tang, Xiangyang; Hsieh, Jiang; Taha, Basel H.; Vass, Melissa L.; Seamans, John L.; Okerlund, Darin R.

    2009-02-01

    With increasing longitudinal detector dimension available in diagnostic volumetric CT, step-and-shoot scan is becoming popular for cardiac imaging. In comparison to helical scan, step-and-shoot scan decouples patient table movement from cardiac gating/triggering, which facilitates the cardiac imaging via multi-sector data acquisition, as well as the administration of inter-cycle heart beat variation (arrhythmia) and radiation dose efficiency. Ideally, a multi-sector data acquisition can improve temporal resolution at a factor the same as the number of sectors (best scenario). In reality, however, the effective temporal resolution is jointly determined by gantry rotation speed and patient heart beat rate, which may significantly lower than the ideal or no improvement (worst scenario). Hence, it is clinically relevant to investigate the behavior of effective temporal resolution in cardiac imaging with multi-sector data acquisition. In this study, a 5-second cine scan of a porcine heart, which cascades 6 porcine cardiac cycles, is acquired. In addition to theoretical analysis and motion phantom study, the clinical consequences due to the effective temporal resolution variation are evaluated qualitative or quantitatively. By employing a 2-sector image reconstruction strategy, a total of 15 (the permutation of P(6, 2)) cases between the best and worst scenarios are studied, providing informative guidance for the design and optimization of CT cardiac imaging in volumetric CT with multi-sector data acquisition.

  14. Astroglia in Thick Tissue with Super Resolution and Cellular Reconstruction

    PubMed Central

    Miller, Sean J.; Rothstein, Jeffrey D.

    2016-01-01

    We utilized the recently published method of passive CLARITY to explore brain astrocytes for the first time with our optimized method. Astrocytes are the fundamental cells in the brain that act to maintain the synaptic activity of neurons, support metabolism of all neurons, and communicate through extensive networks throughout the CNS. They are the defining cell that differentiates lower organisms from humans. From a disease vantage point they are the principal cause of brain tumors and the propagator of neurodegenerative diseases like amyotrophic lateral sclerosis. New methods to study these cells is paramount. Our modified use of CLARITY provides a new way to study these brain cells. To reduce cost, speed up tissue clearing process, reduce human handling error, and to retrieve quantifiable data from single confocal and pseudo-super resolution microscopy we modified and optimized the original protocol. PMID:27494718

  15. Pan-neuronal calcium imaging with cellular resolution in freely swimming zebrafish.

    PubMed

    Kim, Dal Hyung; Kim, Jungsoo; Marques, João C; Grama, Abhinav; Hildebrand, David G C; Gu, Wenchao; Li, Jennifer M; Robson, Drew N

    2017-09-11

    Calcium imaging with cellular resolution typically requires an animal to be tethered under a microscope, which substantially restricts the range of behaviors that can be studied. To expand the behavioral repertoire amenable to imaging, we have developed a tracking microscope that enables whole-brain calcium imaging with cellular resolution in freely swimming larval zebrafish. This microscope uses infrared imaging to track a target animal in a behavior arena. On the basis of the predicted trajectory of the animal, we applied optimal control theory to a motorized stage system to cancel brain motion in three dimensions. We combined this motion-cancellation system with differential illumination focal filtering, a variant of HiLo microscopy, which enabled us to image the brain of a freely swimming larval zebrafish for more than an hour. This work expands the repertoire of natural behaviors that can be studied with cellular-resolution calcium imaging to potentially include spatial navigation, social behavior, feeding and reward.

  16. Direct high-resolution label-free imaging of cellular nanostructure dynamics in living cells

    NASA Astrophysics Data System (ADS)

    Heo, Chaejeong; Lee, Sohee; Lee, Si Young; Jeong, Mun Seok; Lee, Young Hee; Suh, Minah

    2013-06-01

    We report the application of an optical microscope equipped with a high-resolution dark-field condenser for detecting dynamic responses of cellular nanostructures in real time. Our system provides an easy-to-use technique to visualize biological specimens without any staining. This system can visualize the dynamic behavior of nanospheres and nanofibers, such as F-actin, at the leading edges of adjacent neuronal cells. We confirmed that the nanofibers imaged with this high-resolution optical microscopic technique are F-actin by using fluorescence microscopy after immunostaining the F-actin of fixed cells. Furthermore, cellular dynamics are enhanced by applying noncontact electric field stimulation through a transparent graphene electric field stimulator. High-resolution label-free optical microscopy enables the visualization of nanofiber dynamics initiated by filopodial nanofiber contacts. In conclusion, our optical microscopy system allows the visualization of nanoscale cellular dynamics under various external stimuli in real time without specific staining.

  17. High Resolution Quantification of Cellular Forces for Rigidity Sensing

    NASA Astrophysics Data System (ADS)

    Liu, Shuaimin

    density of CUs decrease with time after spreading on stiff substrate. However addition of EGF dramatically increased local contraction activity such that about 30% of the total contractility was in the contraction units. This stimulatory effect was only observed on stiff substrate not on soft. Moreover, we find that in the early interactions of cells with rigid substrates that EGFR activity is needed for normal spreading and the assembly of local contraction units in media lacking serum and any soluble EGF. In Chapter 5, we performed high temporal- and spatial-resolution tracking of contractile forces exerted by cells on sub-micron elastomeric pillars. We found that actomyosin-based sarcomere-like CUs simultaneously moved opposing pillars in net steps of ˜2.5 nm, independent of rigidity. What correlated with rigidity was the number of steps taken to reach a force level that activated recruitment of alpha-actinin to the CUs. When we removed actomyosin restriction by depleting tropomyosin 2.1, we observed larger steps and higher forces that resulted in aberrant rigidity sensing and growth of non-transformed cells on soft matrices. Thus, we conclude that tropomyosin 2.1 acts as a suppressor of growth on soft matrices by supporting proper rigidity sensing.

  18. Super-Resolution Microscopy: Shedding Light on the Cellular Plasma Membrane.

    PubMed

    Stone, Matthew B; Shelby, Sarah A; Veatch, Sarah L

    2017-02-17

    Lipids and the membranes they form are fundamental building blocks of cellular life, and their geometry and chemical properties distinguish membranes from other cellular environments. Collective processes occurring within membranes strongly impact cellular behavior and biochemistry, and understanding these processes presents unique challenges due to the often complex and myriad interactions between membrane components. Super-resolution microscopy offers a significant gain in resolution over traditional optical microscopy, enabling the localization of individual molecules even in densely labeled samples and in cellular and tissue environments. These microscopy techniques have been used to examine the organization and dynamics of plasma membrane components, providing insight into the fundamental interactions that determine membrane functions. Here, we broadly introduce the structure and organization of the mammalian plasma membrane and review recent applications of super-resolution microscopy to the study of membranes. We then highlight some inherent challenges faced when using super-resolution microscopy to study membranes, and we discuss recent technical advancements that promise further improvements to super-resolution microscopy and its application to the plasma membrane.

  19. Cellular resolution multiplexed FLIM tomography with dual-color Bessel beam.

    PubMed

    Xu, Dongli; Zhou, Weibin; Peng, Leilei

    2017-02-01

    Fourier multiplexed FLIM (FmFLIM) tomography enables multiplexed 3D lifetime imaging of whole embryos. In our previous FmFLIM system, the spatial resolution was limited to 25 μm because of the trade-off between the spatial resolution and the imaging depth. In order to achieve cellular resolution imaging of thick specimens, we built a tomography system with dual-color Bessel beam. In combination with FmFLIM, the Bessel FmFLIM tomography system can perform parallel 3D lifetime imaging on multiple excitation-emission channels at a cellular resolution of 2.8 μm. The image capability of the Bessel FmFLIM tomography system was demonstrated by 3D lifetime imaging of dual-labeled transgenic zebrafish embryos.

  20. Cellular resolution multiplexed FLIM tomography with dual-color Bessel beam

    PubMed Central

    Xu, Dongli; Zhou, Weibin; Peng, Leilei

    2017-01-01

    Fourier multiplexed FLIM (FmFLIM) tomography enables multiplexed 3D lifetime imaging of whole embryos. In our previous FmFLIM system, the spatial resolution was limited to 25 μm because of the trade-off between the spatial resolution and the imaging depth. In order to achieve cellular resolution imaging of thick specimens, we built a tomography system with dual-color Bessel beam. In combination with FmFLIM, the Bessel FmFLIM tomography system can perform parallel 3D lifetime imaging on multiple excitation-emission channels at a cellular resolution of 2.8 μm. The image capability of the Bessel FmFLIM tomography system was demonstrated by 3D lifetime imaging of dual-labeled transgenic zebrafish embryos. PMID:28270968

  1. Volumetric apparatus for hydrogen adsorption and diffusion measurements: sources of systematic error and impact of their experimental resolutions.

    PubMed

    Policicchio, Alfonso; Maccallini, Enrico; Kalantzopoulos, Georgios N; Cataldi, Ugo; Abate, Salvatore; Desiderio, Giovanni; Agostino, Raffaele Giuseppe

    2013-10-01

    The development of a volumetric apparatus (also known as a Sieverts' apparatus) for accurate and reliable hydrogen adsorption measurement is shown. The instrument minimizes the sources of systematic errors which are mainly due to inner volume calibration, stability and uniformity of the temperatures, precise evaluation of the skeletal volume of the measured samples, and thermodynamical properties of the gas species. A series of hardware and software solutions were designed and introduced in the apparatus, which we will indicate as f-PcT, in order to deal with these aspects. The results are represented in terms of an accurate evaluation of the equilibrium and dynamical characteristics of the molecular hydrogen adsorption on two well-known porous media. The contribution of each experimental solution to the error propagation of the adsorbed moles is assessed. The developed volumetric apparatus for gas storage capacity measurements allows an accurate evaluation over a 4 order-of-magnitude pressure range (from 1 kPa to 8 MPa) and in temperatures ranging between 77 K and 470 K. The acquired results are in good agreement with the values reported in the literature.

  2. Volumetric apparatus for hydrogen adsorption and diffusion measurements: Sources of systematic error and impact of their experimental resolutions

    SciTech Connect

    Policicchio, Alfonso; Maccallini, Enrico; Kalantzopoulos, Georgios N.; Cataldi, Ugo; Abate, Salvatore; Desiderio, Giovanni

    2013-10-15

    The development of a volumetric apparatus (also known as a Sieverts’ apparatus) for accurate and reliable hydrogen adsorption measurement is shown. The instrument minimizes the sources of systematic errors which are mainly due to inner volume calibration, stability and uniformity of the temperatures, precise evaluation of the skeletal volume of the measured samples, and thermodynamical properties of the gas species. A series of hardware and software solutions were designed and introduced in the apparatus, which we will indicate as f-PcT, in order to deal with these aspects. The results are represented in terms of an accurate evaluation of the equilibrium and dynamical characteristics of the molecular hydrogen adsorption on two well-known porous media. The contribution of each experimental solution to the error propagation of the adsorbed moles is assessed. The developed volumetric apparatus for gas storage capacity measurements allows an accurate evaluation over a 4 order-of-magnitude pressure range (from 1 kPa to 8 MPa) and in temperatures ranging between 77 K and 470 K. The acquired results are in good agreement with the values reported in the literature.

  3. One-micron resolution optical coherence tomography (OCT) in vivo for cellular level imaging

    NASA Astrophysics Data System (ADS)

    Cui, Dongyao; Liu, Xinyu; Zhang, Jing; Yu, Xiaojun; Sun, Ding; Luo, Yuemei; Gu, Jun; Shum, Ping; Liu, Linbo

    2015-03-01

    We developed a spectral domain OCT system combining two NIR, CW light sources of different spectral range. Its resolving power is validated by visualizing the cellular structures of zebra fish larvae in vivo. An NIR extended illumination from 755-1100 nm is achieved. The axial resolution is 1.27 μm in air, corresponding to 0.93μm in tissue (n=1.36), which is the highest axial resolution using NIR, CW laser sources up to date to the best of our knowledge. In vivo imaging is conducted to demonstrate the resolving power of proposed one-micron resolution OCT system. The top and bottom surfaces of individual disk-like red blood cell is reliably visualized, as well as flat, spindle shaped endothelial cells lining along the luminal surface of the blood vessel wall. This study provides a viable solution for cellular and subcellular level OCT imaging system which is also very competitive in cost.

  4. Three-dimensional super-resolution protein localization correlated with vitrified cellular context.

    PubMed

    Liu, Bei; Xue, Yanhong; Zhao, Wei; Chen, Yan; Fan, Chunyan; Gu, Lusheng; Zhang, Yongdeng; Zhang, Xiang; Sun, Lei; Huang, Xiaojun; Ding, Wei; Sun, Fei; Ji, Wei; Xu, Tao

    2015-10-14

    We demonstrate the use of cryogenic super-resolution correlative light and electron microscopy (csCLEM) to precisely determine the spatial relationship between proteins and their native cellular structures. Several fluorescent proteins (FPs) were found to be photoswitchable and emitted far more photons under our cryogenic imaging condition, resulting in higher localization precision which is comparable to ambient super-resolution imaging. Vitrified specimens were prepared by high pressure freezing and cryo-sectioning to maintain a near-native state with better fluorescence preservation. A 2-3-fold improvement of resolution over the recent reports was achieved due to the photon budget performance of screening out Dronpa and optimized imaging conditions, even with thin sections which is at a disadvantage when calculate the structure resolution from label density. We extended csCLEM to mammalian cells by introducing cryo-sectioning and observed good correlation of a mitochondrial protein with the mitochondrial outer membrane at nanometer resolution in three dimensions.

  5. Real-time GPU-accelerated processing and volumetric display for wide-field laser-scanning optical-resolution photoacoustic microscopy

    PubMed Central

    Kang, Heesung; Lee, Sang-Won; Lee, Eun-Soo; Kim, Se-Hwa; Lee, Tae Geol

    2015-01-01

    Fast signal processing and real-time displays are essential for practical imaging modality in various fields of applications. However, the imaging speed in optical-resolution photoacoustic microscopy (OR-PAM), in particular, depends on factors such as the pulse repetition rate of the laser, scanning method, field of view (FOV), and signal processing time. In the past, efforts to increase acquisition speed either focused on developing new scanning methods or using lasers with higher pulse repetition rates. However, high-speed signal processing is also important for real-time volumetric display in OR-PAM. In this study, we carried out parallel signal processing using a graphics processing unit (GPU) to enable fast signal processing and wide-field real-time displays in laser-scanning OR-PAM. The average total GPU processing time for a B-mode PAM image was approximately 1.35 ms at a display speed of 480 fps when the data samples were acquired with 736 (axial) × 500 (lateral) points/B-mode-frame at a pulse repetition rate of 300 kHz. In addition, we successfully displayed maximum amplitude projection images of a mouse’s ear as volumetric images with an FOV of 3 mm × 3 mm (500 × 500 pixels) at 1.02 s, corresponding to 0.98 fps. PMID:26713184

  6. Cellular resolution functional imaging in behaving rats using voluntary head restraint

    PubMed Central

    Scott, Benjamin B.; Brody, Carlos D.; Tank, David W.

    2013-01-01

    SUMMARY High-throughput operant conditioning systems for rodents provide efficient training on sophisticated behavioral tasks. Combining these systems with technologies for cellular resolution functional imaging would provide a powerful approach to study neural dynamics during behavior. Here we describe an integrated two-photon microscope and behavioral apparatus that allows cellular resolution functional imaging of cortical regions during epochs of voluntary head restraint. Rats were trained to initiate periods of restraint up to 8 seconds in duration, which provided the mechanical stability necessary for in vivo imaging while allowing free movement between behavioral trials. A mechanical registration system repositioned the head to within a few microns, allowing the same neuronal populations to be imaged on each trial. In proof-of-principle experiments, calcium dependent fluorescence transients were recorded from GCaMP-labeled cortical neurons. In contrast to previous methods for head restraint, this system can also be incorporated into high-throughput operant conditioning systems. PMID:24055015

  7. Sub-cellular resolution imaging with Gabor domain optical coherence microscopy

    NASA Astrophysics Data System (ADS)

    Meemon, P.; Lee, K. S.; Murali, S.; Kaya, I.; Thompson, K. P.; Rolland, J. P.

    2010-02-01

    Optical Coherence Microscopy (OCM) utilizes a high NA microscope objective in the sample arm to achieve an axially and laterally high resolution OCT image. An increase in NA, however, leads to a dramatically decreased depth of focus (DOF), and hence shortens the imaging depth range so that high lateral resolution is maintained only within a small depth region around the focal plane. One solution to increase the depth of imaging while keeping a high lateral resolution is dynamic-focusing. Utilizing the voltage controlled refocus capability of a liquid lens, we have recently presented a solution for invariant high resolution imaging using the liquid lens embedded within a fixed optics hand-held custom microscope designed specifically for optical imaging systems using a broadband light source at 800 nm center wavelength. Subsequently, we have developed a Gabor-Domain Optical Coherence Microscopy (GD-OCM) that utilizes the high speed imaging of spectral domain OCT, the high lateral resolution of OCM, and the ability of real time refocusing of our custom design variable focus objective. In this paper we demonstrate in detail how portions of the infocus cross-sectional images can be extracted and fused to form an invariant lateral resolution image with multiple crosssectional images acquired corresponding to a discrete refocusing step along depth enabled by the varifocal probe. We demonstrate sub-cellular resolution imaging of an African frog tadpole (Xenopus Laevis) taken from a 500 μm x 500 μm cross-section.

  8. FishFace: interactive atlas of zebrafish craniofacial development at cellular resolution

    PubMed Central

    2013-01-01

    Background The vertebrate craniofacial skeleton may exhibit anatomical complexity and diversity, but its genesis and evolution can be understood through careful dissection of developmental programs at cellular resolution. Resources are lacking that include introductory overviews of skeletal anatomy coupled with descriptions of craniofacial development at cellular resolution. In addition to providing analytical guidelines for other studies, such an atlas would suggest cellular mechanisms underlying development. Description We present the Fish Face Atlas, an online, 3D-interactive atlas of craniofacial development in the zebrafish Danio rerio. Alizarin red-stained skulls scanned by fluorescent optical projection tomography and segmented into individual elements provide a resource for understanding the 3D structure of the zebrafish craniofacial skeleton. These data provide the user an anatomical entry point to confocal images of Alizarin red-stained zebrafish with transgenically-labelled pharyngeal arch ectomesenchyme, chondrocytes, and osteoblasts, which illustrate the appearance, morphogenesis, and growth of the mandibular and hyoid cartilages and bones, as viewed in live, anesthetized zebrafish during embryonic and larval development. Confocal image stacks at high magnification during the same stages provide cellular detail and suggest developmental and evolutionary hypotheses. Conclusion The FishFace Atlas is a novel learning tool for understanding craniofacial skeletal development, and can serve as a reference for a variety of studies, including comparative and mutational analyses. PMID:23714426

  9. FishFace: interactive atlas of zebrafish craniofacial development at cellular resolution.

    PubMed

    Eames, B Frank; DeLaurier, April; Ullmann, Bonnie; Huycke, Tyler R; Nichols, James T; Dowd, John; McFadden, Marcie; Sasaki, Mark M; Kimmel, Charles B

    2013-05-28

    The vertebrate craniofacial skeleton may exhibit anatomical complexity and diversity, but its genesis and evolution can be understood through careful dissection of developmental programs at cellular resolution. Resources are lacking that include introductory overviews of skeletal anatomy coupled with descriptions of craniofacial development at cellular resolution. In addition to providing analytical guidelines for other studies, such an atlas would suggest cellular mechanisms underlying development. We present the Fish Face Atlas, an online, 3D-interactive atlas of craniofacial development in the zebrafish Danio rerio. Alizarin red-stained skulls scanned by fluorescent optical projection tomography and segmented into individual elements provide a resource for understanding the 3D structure of the zebrafish craniofacial skeleton. These data provide the user an anatomical entry point to confocal images of Alizarin red-stained zebrafish with transgenically-labelled pharyngeal arch ectomesenchyme, chondrocytes, and osteoblasts, which illustrate the appearance, morphogenesis, and growth of the mandibular and hyoid cartilages and bones, as viewed in live, anesthetized zebrafish during embryonic and larval development. Confocal image stacks at high magnification during the same stages provide cellular detail and suggest developmental and evolutionary hypotheses. The FishFace Atlas is a novel learning tool for understanding craniofacial skeletal development, and can serve as a reference for a variety of studies, including comparative and mutational analyses.

  10. Label-free imaging of cellular malformation using high resolution photoacoustic microscopy

    NASA Astrophysics Data System (ADS)

    Chen, Zhongjiang; Li, Bingbing; Yang, Sihua

    2014-09-01

    A label-free high resolution photoacoustic microscopy (PAM) system for imaging cellular malformation is presented. The carbon fibers were used to testify the lateral resolution of the PAM. Currently, the lateral resolution is better than 2.7 μm. The human normal red blood cells (RBCs) were used to prove the imaging capability of the system, and a single red blood cell was mapped with high contrast. Moreover, the iron deficiency anemia RBCs were clearly distinguished from the cell morphology by using the PAM. The experimental results demonstrate that the photoacoustic microscopy system can accomplish label-free photoacoustic imaging and that it has clinical potential for use in the detection of erythrocytes and blood vessels malformation.

  11. Aptamers provide superior stainings of cellular receptors studied under super-resolution microscopy

    PubMed Central

    Höbartner, Claudia

    2017-01-01

    Continuous improvements in imaging techniques are challenging biologists to search for more accurate methods to label cellular elements. This is particularly relevant for diffraction-unlimited fluorescence imaging, where the perceived resolution is affected by the size of the affinity probes. This is evident when antibodies, which are 10–15 nm in size, are used. Previously it has been suggested that RNA aptamers (~3 nm) can be used to detect cellular proteins under super-resolution imaging. However, a direct comparison between several aptamers and antibodies is needed, to clearly show the advantages and/or disadvantages of the different probes. Here we have conducted such a comparative study, by testing several aptamers and antibodies using stimulated emission depletion microscopy (STED). We have targeted three membrane receptors, EGFR, ErbB2 and Epha2, which are relevant to human health, and recycle between plasma membrane and intracellular organelles. Our results suggest that the aptamers can reveal more epitopes than most antibodies, thus providing a denser labeling of the stained structures. Moreover, this improves the overall quality of the information that can be extracted from the images. We conclude that aptamers could become useful fluorescent labeling tools for light microscopy and super-resolution imaging, and that their development for novel targets is imperative. PMID:28235049

  12. Three-dimensional super-resolution protein localization correlated with vitrified cellular context

    PubMed Central

    Liu, Bei; Xue, Yanhong; Zhao, Wei; Chen, Yan; Fan, Chunyan; Gu, Lusheng; Zhang, Yongdeng; Zhang, Xiang; Sun, Lei; Huang, Xiaojun; Ding, Wei; Sun, Fei; Ji, Wei; Xu, Tao

    2015-01-01

    We demonstrate the use of cryogenic super-resolution correlative light and electron microscopy (csCLEM) to precisely determine the spatial relationship between proteins and their native cellular structures. Several fluorescent proteins (FPs) were found to be photoswitchable and emitted far more photons under our cryogenic imaging condition, resulting in higher localization precision which is comparable to ambient super-resolution imaging. Vitrified specimens were prepared by high pressure freezing and cryo-sectioning to maintain a near-native state with better fluorescence preservation. A 2-3-fold improvement of resolution over the recent reports was achieved due to the photon budget performance of screening out Dronpa and optimized imaging conditions, even with thin sections which is at a disadvantage when calculate the structure resolution from label density. We extended csCLEM to mammalian cells by introducing cryo-sectioning and observed good correlation of a mitochondrial protein with the mitochondrial outer membrane at nanometer resolution in three dimensions. PMID:26462878

  13. Building quantitative, three dimensional atlases of gene expression and morphology at cellular resolution

    PubMed Central

    Knowles, David W.; Biggin, Mark D.

    2013-01-01

    Animals comprise dynamic three-dimensional arrays of cells that express gene products in intricate spatial and temporal patterns that determine cellular differentiation and morphogenesis. A rigorous understanding of these developmental processes requires automated methods that quantitatively record and analyze complex morphologies and their associated patterns of gene expression at cellular resolution. Here we summarize light microscopy based approaches to establish permanent, quantitative datasets—atlases—that record this information. We focus on experiments that capture data for whole embryos or large areas of tissue in three dimensions, often at multiple time points. We compare and contrast the advantages and limitations of different methods and highlight some of the discoveries made. We emphasize the need for interdisciplinary collaborations and integrated experimental pipelines that link sample preparation, image acquisition, image analysis, database design, visualization and quantitative analysis. PMID:24123936

  14. High-resolution 3-dimensional late gadolinium enhancement scar imaging in surgically corrected Tetralogy of Fallot: clinical feasibility of volumetric quantification and visualization.

    PubMed

    Stirrat, John; Rajchl, Martin; Bergin, Lynn; Patton, David J; Peters, Terry; White, James A

    2014-10-01

    The extent of surgical scarring in Tetralogy of Fallot (TOF) may be a marker of adverse outcomes and provide substrate for ventricular arrhythmia. In this study we evaluate the feasibility of high resolution three dimensional (3D) late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) for volumetric scar quantification in patients with surgically corrected TOF. Fifteen consecutive patients underwent 3D LGE imaging with 3 Tesla CMR using a whole-heart, respiratory-navigated technique. A novel, signal-histogram based segmentation technique was tested for the quantification and modeling of surgical scar. Total scar volume was compared to the gold standard manual expert segmentation. The feasibility of segmented scar fusion to matched coronary CMR data for volumetric display was explored. Image quality sufficient for 3D scar segmentation was acquired in fourteen patients. Mean patient age was 32.2 ± 11.9 years (range 21 to 57 years) with mean right ventricle (RV) ejection fraction (EF) of 53.9 ± 9.2% and mean RV end diastolic volume of 117.0 ± 41.5 mL/m². The mean total scar volume was 11.1 ± 8.2 mL using semi-automated 3D segmentation with excellent correlation to manual expert segmentation (r = 0.99, bias = 0.89 mL, 95% CI -1.66 to 3.44). The mean segmentation time was significantly reduced using the novel semi-automated segmentation technique (10.1 ± 2.6 versus 45.8 ± 12.6 minutes). Excellent intra-observer and good inter-observer reproducibility was observed. 3D high resolution LGE imaging with semi-automated scar segmentation is clinically feasible among patients with surgically corrected TOF and shows excellent accuracy and reproducibility. This approach may offer a valuable clinical tool for risk prediction and procedural planning among this growing population.

  15. High-resolution Fiber-optic Microendoscopy for in situ Cellular Imaging

    PubMed Central

    Pierce, Mark; Yu, Dihua; Richards-Kortum, Rebecca

    2011-01-01

    Many biological and clinical studies require the longitudinal study and analysis of morphology and function with cellular level resolution. Traditionally, multiple experiments are run in parallel, with individual samples removed from the study at sequential time points for evaluation by light microscopy. Several intravital techniques have been developed, with confocal, multiphoton, and second harmonic microscopy all demonstrating their ability to be used for imaging in situ 1. With these systems, however, the required infrastructure is complex and expensive, involving scanning laser systems and complex light sources. Here we present a protocol for the design and assembly of a high-resolution microendoscope which can be built in a day using off-the-shelf components for under US$5,000. The platform offers flexibility in terms of image resolution, field-of-view, and operating wavelength, and we describe how these parameters can be easily modified to meet the specific needs of the end user. We and others have explored the use of the high-resolution microendoscope (HRME) in in vitro cell culture 2-5, in excised 6 and living animal tissues 2,5, and in human tissues in vivo 2,7. Users have reported the use of several different fluorescent contrast agents, including proflavine 2-4, benzoporphyrin-derivative monoacid ring A (BPD-MA) 5, and fluoroscein 6,7, all of which have received full, or investigational approval from the FDA for use in human subjects. High-resolution microendoscopy, in the form described here, may appeal to a wide range of researchers working in the basic and clinical sciences. The technique offers an effective and economical approach which complements traditional benchtop microscopy, by enabling the user to perform high-resolution, longitudinal imaging in situ. PMID:21248707

  16. High-resolution fiber-optic microendoscopy for in situ cellular imaging.

    PubMed

    Pierce, Mark; Yu, Dihua; Richards-Kortum, Rebecca

    2011-01-11

    Many biological and clinical studies require the longitudinal study and analysis of morphology and function with cellular level resolution. Traditionally, multiple experiments are run in parallel, with individual samples removed from the study at sequential time points for evaluation by light microscopy. Several intravital techniques have been developed, with confocal, multiphoton, and second harmonic microscopy all demonstrating their ability to be used for imaging in situ. With these systems, however, the required infrastructure is complex and expensive, involving scanning laser systems and complex light sources. Here we present a protocol for the design and assembly of a high-resolution microendoscope which can be built in a day using off-the-shelf components for under US$5,000. The platform offers flexibility in terms of image resolution, field-of-view, and operating wavelength, and we describe how these parameters can be easily modified to meet the specific needs of the end user. We and others have explored the use of the high-resolution microendoscope (HRME) in in vitro cell culture, in excised and living animal tissues, and in human tissues in vivo. Users have reported the use of several different fluorescent contrast agents, including proflavine, benzoporphyrin-derivative monoacid ring A (BPD-MA), and fluoroscein, all of which have received full, or investigational approval from the FDA for use in human subjects. High-resolution microendoscopy, in the form described here, may appeal to a wide range of researchers working in the basic and clinical sciences. The technique offers an effective and economical approach which complements traditional benchtop microscopy, by enabling the user to perform high-resolution, longitudinal imaging in situ.

  17. Spatial Mapping of Lipids at Cellular Resolution in Embryos of Cotton[W][OA

    PubMed Central

    Horn, Patrick J.; Korte, Andrew R.; Neogi, Purnima B.; Love, Ebony; Fuchs, Johannes; Strupat, Kerstin; Borisjuk, Ljudmilla; Shulaev, Vladimir; Lee, Young-Jin; Chapman, Kent D.

    2012-01-01

    Advances in mass spectrometry (MS) have made comprehensive lipidomics analysis of complex tissues relatively commonplace. These compositional analyses, although able to resolve hundreds of molecular species of lipids in single extracts, lose the original cellular context from which these lipids are derived. Recently, high-resolution MS of individual lipid droplets from seed tissues indicated organelle-to-organelle variation in lipid composition, suggesting that heterogeneity of lipid distributions at the cellular level may be prevalent. Here, we employed matrix-assisted laser desorption/ionization–MS imaging (MALDI-MSI) approaches to visualize lipid species directly in seed tissues of upland cotton (Gossypium hirsutum). MS imaging of cryosections of mature cotton embryos revealed a distinct, heterogeneous distribution of molecular species of triacylglycerols and phosphatidylcholines, the major storage and membrane lipid classes in cotton embryos. Other lipids were imaged, including phosphatidylethanolamines, phosphatidic acids, sterols, and gossypol, indicating the broad range of metabolites and applications for this chemical visualization approach. We conclude that comprehensive lipidomics images generated by MALDI-MSI report accurate, relative amounts of lipid species in plant tissues and reveal previously unseen differences in spatial distributions providing for a new level of understanding in cellular biochemistry. PMID:22337917

  18. 3D Volumetric Analysis of Wind Turbine Wake Properties in the Atmosphere Using High-Resolution Doppler Lidar

    SciTech Connect

    Banta, Robert M.; Pichugina, Yelena L.; Brewer, W. Alan; Lundquist, Julie K.; Kelley, Neil D.; Sandberg, Scott P.; Alvarez II, Raul J.; Hardesty, R. Michael; Weickmann, Ann M.

    2015-05-01

    Wind turbine wakes in the atmosphere are three-dimensional (3D) and time dependent. An important question is how best to measure atmospheric wake properties, both for characterizing these properties observationally and for verification of numerical, conceptual, and physical (e.g., wind tunnel) models of wakes. Here a scanning, pulsed, coherent Doppler lidar is used to sample a turbine wake using 3D volume scan patterns that envelop the wake and simultaneously measure the inflow profile. The volume data are analyzed for quantities of interest, such as peak velocity deficit, downwind variability of the deficit, and downwind extent of the wake, in a manner that preserves the measured data. For the case study presented here, in which the wake was well defined in the lidar data, peak deficits of up to 80% were measured 0.6-2 rotor diameters (D) downwind of the turbine, and the wakes extended more than 11D downwind. Temporal wake variability over periods of minutes and the effects of atmospheric gusts and lulls in the inflow are demonstrated in the analysis. Lidar scanning trade-offs important to ensuring that the wake quantities of interest are adequately sampled by the scan pattern, including scan coverage, number of scans per volume, data resolution, and scan-cycle repeat interval, are discussed.

  19. Investigating spatial and volumetric trends in silicic volcanism along the Yellowstone hotspot track using high-resolution thermomechanical numerical models

    NASA Astrophysics Data System (ADS)

    Colon, D.; Bindeman, I. N.; Gerya, T.

    2015-12-01

    Roughly 2 Ma gaps exist between the Picabo and Heise (from ~8.4 to 6.6Ma) and the Heise and Yellowstone (4.40 to 2.1 Ma) centers along the Yellowstone hotspot track, each of which experienced magmatic activity for several million years. We employ high-resolution magmatic-thermomechanical models of the interaction between a mantle plume and thick continental crust to investigate the causes of the spatial and temporal jumps that occur between these eruptive centers, using a stress implementation of magmatic processes, nonlinear temperature-dependent melting, and progressive depletion the rocks from which magmas are extracted. We investigate two possible mechanisms of these jumps in active centers. First, the spacing between eruptive centers is a function of the longevity of amagma conduit in beneath each eruptive center, which must be abandoned when the crust moves too far away from the center of the hotspot, with the distance traveled by the plate in this time determining the spacing between eruptive centers. Alternatively, the cessation of activity at a given eruptive center is controlled by the formation of geochemically depleted "dead zones" which force any new silicic volcanism to occur in a new area of less depleted crust, with the spacing between centers controlled by the size of these dead zones. By varying the speed of the crust over the hotspot, the thickness and composition of the crust, we can determine the relative importance of these two processes for volcanism along the Yellowstone hotspot track has likely changed over time, with implications for changes in average eruptive volumes and repose times between large eruptions over the last 12 Ma. Early results suggest that heating of the crust causes areas of melt accumulation to move upward with time before resetting to a deeper level as the crust moves over the hotspot, a possible additional source of discrete behavior along the hotspot track. We check our results using existing geochemical constraints.

  20. Simultaneous all-optical manipulation and recording of neural circuit activity with cellular resolution in vivo.

    PubMed

    Packer, Adam M; Russell, Lloyd E; Dalgleish, Henry W P; Häusser, Michael

    2015-02-01

    We describe an all-optical strategy for simultaneously manipulating and recording the activity of multiple neurons with cellular resolution in vivo. We performed simultaneous two-photon optogenetic activation and calcium imaging by coexpression of a red-shifted opsin and a genetically encoded calcium indicator. A spatial light modulator allows tens of user-selected neurons to be targeted for spatiotemporally precise concurrent optogenetic activation, while simultaneous fast calcium imaging provides high-resolution network-wide readout of the manipulation with negligible optical cross-talk. Proof-of-principle experiments in mouse barrel cortex demonstrate interrogation of the same neuronal population during different behavioral states and targeting of neuronal ensembles based on their functional signature. This approach extends the optogenetic toolkit beyond the specificity obtained with genetic or viral approaches, enabling high-throughput, flexible and long-term optical interrogation of functionally defined neural circuits with single-cell and single-spike resolution in the mouse brain in vivo.

  1. The functional micro-organization of grid cells revealed by cellular-resolution imaging.

    PubMed

    Heys, James G; Rangarajan, Krsna V; Dombeck, Daniel A

    2014-12-03

    Establishing how grid cells are anatomically arranged, on a microscopic scale, in relation to their firing patterns in the environment would facilitate a greater microcircuit-level understanding of the brain's representation of space. However, all previous grid cell recordings used electrode techniques that provide limited descriptions of fine-scale organization. We therefore developed a technique for cellular-resolution functional imaging of medial entorhinal cortex (MEC) neurons in mice navigating a virtual linear track, enabling a new experimental approach to study MEC. Using these methods, we show that grid cells are physically clustered in MEC compared to nongrid cells. Additionally, we demonstrate that grid cells are functionally micro-organized: the similarity between the environment firing locations of grid cell pairs varies as a function of the distance between them according to a "Mexican hat"-shaped profile. This suggests that, on average, nearby grid cells have more similar spatial firing phases than those further apart.

  2. Neurotransmitter Specific, Cellular-Resolution Functional Brain Mapping Using Receptor Coated Nanoparticles: Assessment of the Possibility

    PubMed Central

    Forati, Ebrahim; Sabouni, Abas; Ray, Supriyo; Head, Brian; Schoen, Christian; Sievenpiper, Dan

    2015-01-01

    Receptor coated resonant nanoparticles and quantum dots are proposed to provide a cellular-level resolution image of neural activities inside the brain. The functionalized nanoparticles and quantum dots in this approach will selectively bind to different neurotransmitters in the extra-synaptic regions of neurons. This allows us to detect neural activities in real time by monitoring the nanoparticles and quantum dots optically. Gold nanoparticles (GNPs) with two different geometries (sphere and rod) and quantum dots (QDs) with different sizes were studied along with three different neurotransmitters: dopamine, gamma-Aminobutyric acid (GABA), and glycine. The absorption/emission spectra of GNPs and QDs before and after binding of neurotransmitters and their corresponding receptors are reported. The results using QDs and nanorods with diameter 25nm and aspect rations larger than three were promising for the development of the proposed functional brain mapping approach. PMID:26717196

  3. Multi-resolution 3D visualization of the early stages of cellular uptake of peptide-coated nanoparticles

    SciTech Connect

    Welsher, Kevin; Yang, Haw

    2014-02-23

    A detailed understanding of the cellular uptake process is essential to the development of cellular delivery strategies and to the study of viral trafficking. However, visualization of the entire process, encompassing the fast dynamics (local to the freely diffusing nanoparticle) as well the state of the larger-scale cellular environment, remains challenging. Here, we introduce a three-dimensional multi-resolution method to capture, in real time, the transient events leading to cellular binding and uptake of peptide (HIV1-Tat)-modified nanoparticles. Applying this new method to observe the landing of nanoparticles on the cellular contour in three dimensions revealed long-range deceleration of the delivery particle, possibly due to interactions with cellular receptors. Furthermore, by using the nanoparticle as a nanoscale ‘dynamics pen’, we discovered an unexpected correlation between small membrane terrain structures and local nanoparticle dynamics. This approach could help to reveal the hidden mechanistic steps in a variety of multiscale processes.

  4. Micropatterned silicone elastomer substrates for high resolution analysis of cellular force patterns

    NASA Astrophysics Data System (ADS)

    Cesa, Claudia M.; Kirchgeßner, Norbert; Mayer, Dirk; Schwarz, Ulrich S.; Hoffmann, Bernd; Merkel, Rudolf

    2007-03-01

    Cellular forces are closely related to many physiological processes, including cell migration, growth, division, and differentiation. Here, we describe newly developed techniques to measure these forces with high spatial resolution. Our approach is based on ultrasoft silicone elastomer films with a regular microstructure molded into the surface. Mechanical forces applied by living cells to such films result in elastomer deformation which can be quantified by video microscopy and digital image processing. From this deformation field forces can be calculated. Here we give detailed accounts of the following issues: (1) the preparation of silicon wafers as molds for the microstructures, (2) the fabrication of microstructured elastomer substrates, (3) the in-depth characterization of the mechanical properties of these elastomers, (4) the image processing algorithms for the extraction of cellular deformation fields, and (5) the generalized first moment tensor as a robust mathematical tool to characterize whole cell activity. We present prototype experiments on living myocytes as well as on cardiac fibroblasts and discuss the characteristics and performance of our force measurement technique.

  5. Volumetric magnetic induction tomography

    NASA Astrophysics Data System (ADS)

    Wei, H.-Y.; Ma, L.; Soleimani, M.

    2012-05-01

    Magnetic induction tomography (MIT) is a new and emerging type of tomography technique that is able to map the passive electromagnetic properties (in particular conductivity) of an object. Because of its non-invasive feature, it becomes a suitable technique for many industries, such as metal processing and mining. This paper presents a volumetric MIT (VMIT) system based on an existing measurement setup in our 2D system (MIT Mk-I). By increasing the number of sensors in the axial direction, volumetric imaging can be realized and hence can improve the spatial resolution of the reconstructed images. All of the system control, data acquisition and signal demodulation are accomplished by a commercial data acquisition card and the National Instruments graphical programming language. In this paper, both the system architecture and the forward 3D sensitivity model will be presented. The image reconstruction scheme is modified by introducing a 3D sensitivity map to replace the previous 2D sensitivity map used for the MIT Mk-I system. The iterative Landweber technique was implemented as the inverse solver to reconstruct the images. Several laboratory-based experimental results are demonstrated in this paper, with different shapes of imaging objects. The reconstructed images are satisfactory showing for the first time volumetric conductivity reconstruction using a multi-layer MIT system. The results indicate the high-quality image reconstruction using our novel VMIT system for potential use in industrial applications, such as metal flow imaging.

  6. An Adaptive Control Method for Ros-Drill Cellular Microinjector with Low-Resolution Encoder

    PubMed Central

    Zhang, Zhenyu; Olgac, Nejat

    2013-01-01

    A novel control methodology which uses a low-resolution encoder is presented for a cellular microinjection technology called the Ros-Drill (rotationally oscillating drill). It is developed primarily for ICSI (intracytoplasmic sperm injection) operations, with the objective of generating a desired oscillatory motion at the tip of a micro glass pipette. It is an inexpensive setup, which creates high-frequency (higher than 500 Hz) and small-amplitude (around 0.2 deg) rotational oscillations at the tip of an injection pipette. These rotational oscillations enable the pipette to drill into cell membranes with minimum biological damage. Such a motion control procedure presents no particular difficulty when it uses sufficiently precise motion sensors. However, size, costs, and accessibility of technology to the hardware components severely constrain the sensory capabilities. Consequently, the control mission and the trajectory tracking are adversely affected. This paper presents two contributions: (a) a dedicated novel adaptive feedback control method to achieve a satisfactory trajectory tracking capability. We demonstrate via experiments that the tracking of the harmonic rotational motion is achieved with desirable fidelity; (b) some important analytical features and related observations associated with the controlled harmonic motion which is created by the low-resolution feedback control structure. PMID:27006914

  7. In vivo reflectance confocal microscopy detects pigmentary changes in melasma at a cellular level resolution.

    PubMed

    Kang, Hee Young; Bahadoran, Philippe; Suzuki, Itaru; Zugaj, Didier; Khemis, Abdallah; Passeron, Thierry; Andres, Philippe; Ortonne, Jean-Paul

    2010-08-01

    Melasma is a frequent pigmentary disorder caused by abnormal melanin deposits in the skin. In vivo reflectance confocal microscopy (RCM) is a repetitive imaging tool that provides real-time images of the skin at nearly histological resolution. As melanin is the strongest endogenous contrast in human skin, pigmentary disorders are the most suitable candidates for RCM examination but RCM features of melasma have never been reported. This study investigates the pilot use of RCM in melasma to provide a set of well-described morphological criteria with histological correlations. RCM images were acquired from melasma skin and compared to adjacent control skin in 26 patients. Skin biopsies were obtained from eight patients. In the epidermis, RCM showed in all patients a significant increase in hyperrefractile cobblestoning cells. These cells corresponded to hyperpigmented basal keratinocytes in histology. In six patients, dendritic cells corresponding to activated melanocytes were also found in the epidermis. In the dermis, RCM identified in nine patients plump bright cells corresponding to melanophages. Interestingly, for a given patient, the topographic distribution of melanophages in melasma lesions was very heterogeneous. RCM also showed a significant increase in solar elastosis and blood vessels in the dermis. RCM is a non-invasive technique that detects pigmentary changes in melasma at a cellular level resolution. Therefore, RCM provides an innovative way to classify melasma by pigment changes.

  8. Electron microscopy of high pressure frozen samples: bridging the gap between cellular ultrastructure and atomic resolution.

    PubMed

    Studer, Daniel; Humbel, Bruno M; Chiquet, Matthias

    2008-11-01

    Transmission electron microscopy has provided most of what is known about the ultrastructural organization of tissues, cells, and organelles. Due to tremendous advances in crystallography and magnetic resonance imaging, almost any protein can now be modeled at atomic resolution. To fully understand the workings of biological "nanomachines" it is necessary to obtain images of intact macromolecular assemblies in situ. Although the resolution power of electron microscopes is on the atomic scale, in biological samples artifacts introduced by aldehyde fixation, dehydration and staining, but also section thickness reduces it to some nanometers. Cryofixation by high pressure freezing circumvents many of the artifacts since it allows vitrifying biological samples of about 200 mum in thickness and immobilizes complex macromolecular assemblies in their native state in situ. To exploit the perfect structural preservation of frozen hydrated sections, sophisticated instruments are needed, e.g., high voltage electron microscopes equipped with precise goniometers that work at low temperature and digital cameras of high sensitivity and pixel number. With them, it is possible to generate high resolution tomograms, i.e., 3D views of subcellular structures. This review describes theory and applications of the high pressure cryofixation methodology and compares its results with those of conventional procedures. Moreover, recent findings will be discussed showing that molecular models of proteins can be fitted into depicted organellar ultrastructure of images of frozen hydrated sections. High pressure freezing of tissue is the base which may lead to precise models of macromolecular assemblies in situ, and thus to a better understanding of the function of complex cellular structures.

  9. Identification of the direction of the neural network activation with a cellular resolution by fast two-photon imaging

    NASA Astrophysics Data System (ADS)

    Liu, Xiuli; Quan, Tingwei; Zeng, Shaoqun; Lv, Xiaohua

    2011-08-01

    Spatiotemporal activity patterns in local neural networks are fundamental to understanding how information is processed and stored in brain microcircuits. Currently, imaging techniques are able to map the directional activation of macronetworks across brain areas; however, these strategies still fail to resolve the activation direction for fine microcircuits with cellular spatial resolution. Here, we show the capability to identify the activation direction of a multicell network with a cellular resolution and millisecond precision by using fast two-photon microscopy and cross correlation procedures. As an example, we characterized a directional neuronal network in an epilepsy brain slice to provide different initiation delay among multiple neurons defined at a millisecond scale.

  10. Boron dipyrromethene (BODIPY) functionalized carbon nano-onions for high resolution cellular imaging

    NASA Astrophysics Data System (ADS)

    Bartelmess, Juergen; de Luca, Elisa; Signorelli, Angelo; Baldrighi, Michele; Becce, Michele; Brescia, Rosaria; Nardone, Valentina; Parisini, Emilio; Echegoyen, Luis; Pompa, Pier Paolo; Giordani, Silvia

    2014-10-01

    Carbon nano-onions (CNOs) are an exciting class of carbon nanomaterials, which have recently demonstrated a facile cell-penetration capability. In the present work, highly fluorescent boron dipyrromethene (BODIPY) dyes were covalently attached to the surface of CNOs. The introduction of this new carbon nanomaterial-based imaging platform, made of CNOs and BODIPY fluorophores, allows for the exploration of synergetic effects between the two building blocks and for the elucidation of its performance in biological applications. The high fluorescence intensity exhibited by the functionalized CNOs translates into an excellent in vitro probe for the high resolution imaging of MCF-7 human breast cancer cells. It was also found that the CNOs, internalized by the cells by endocytosis, localized in the lysosomes and did not show any cytotoxic effects. The presented results highlight CNOs as excellent platforms for biological and biomedical studies due to their low toxicity, efficient cellular uptake and low fluorescence quenching of attached probes.Carbon nano-onions (CNOs) are an exciting class of carbon nanomaterials, which have recently demonstrated a facile cell-penetration capability. In the present work, highly fluorescent boron dipyrromethene (BODIPY) dyes were covalently attached to the surface of CNOs. The introduction of this new carbon nanomaterial-based imaging platform, made of CNOs and BODIPY fluorophores, allows for the exploration of synergetic effects between the two building blocks and for the elucidation of its performance in biological applications. The high fluorescence intensity exhibited by the functionalized CNOs translates into an excellent in vitro probe for the high resolution imaging of MCF-7 human breast cancer cells. It was also found that the CNOs, internalized by the cells by endocytosis, localized in the lysosomes and did not show any cytotoxic effects. The presented results highlight CNOs as excellent platforms for biological and biomedical

  11. High resolution simulations of energy absorption in dynamically loaded cellular structures

    NASA Astrophysics Data System (ADS)

    Winter, R. E.; Cotton, M.; Harris, E. J.; Eakins, D. E.; McShane, G.

    2016-04-01

    Cellular materials have potential application as absorbers of energy generated by high velocity impact. CTH, a Sandia National Laboratories Code which allows very severe strains to be simulated, has been used to perform very high resolution simulations showing the dynamic crushing of a series of two-dimensional, stainless steel metal structures with varying architectures. The structures are positioned to provide a cushion between a solid stainless steel flyer plate with velocities ranging from 300 to 900 m/s, and an initially stationary stainless steel target. Each of the alternative architectures under consideration was formed by an array of identical cells each of which had a constant volume and a constant density. The resolution of the simulations was maximised by choosing a configuration in which one-dimensional conditions persisted for the full period over which the specimen densified, a condition which is most readily met by impacting high density specimens at high velocity. It was found that the total plastic flow and, therefore, the irreversible energy dissipated in the fully densified energy absorbing cell, increase (a) as the structure becomes more rodlike and less platelike and (b) as the impact velocity increases. Sequential CTH images of the deformation processes show that the flow of the cell material may be broadly divided into macroscopic flow perpendicular to the compression direction and jetting-type processes (microkinetic flow) which tend to predominate in rod and rodlike configurations and also tend to play an increasing role at increased strain rates. A very simple analysis of a configuration in which a solid flyer impacts a solid target provides a baseline against which to compare and explain features seen in the simulations. The work provides a basis for the development of energy absorbing structures for application in the 200-1000 m/s impact regime.

  12. High resolution simulations of energy absorption in dynamically loaded cellular structures

    NASA Astrophysics Data System (ADS)

    Winter, R. E.; Cotton, M.; Harris, E. J.; Eakins, D. E.; McShane, G.

    2017-03-01

    Cellular materials have potential application as absorbers of energy generated by high velocity impact. CTH, a Sandia National Laboratories Code which allows very severe strains to be simulated, has been used to perform very high resolution simulations showing the dynamic crushing of a series of two-dimensional, stainless steel metal structures with varying architectures. The structures are positioned to provide a cushion between a solid stainless steel flyer plate with velocities ranging from 300 to 900 m/s, and an initially stationary stainless steel target. Each of the alternative architectures under consideration was formed by an array of identical cells each of which had a constant volume and a constant density. The resolution of the simulations was maximised by choosing a configuration in which one-dimensional conditions persisted for the full period over which the specimen densified, a condition which is most readily met by impacting high density specimens at high velocity. It was found that the total plastic flow and, therefore, the irreversible energy dissipated in the fully densified energy absorbing cell, increase (a) as the structure becomes more rodlike and less platelike and (b) as the impact velocity increases. Sequential CTH images of the deformation processes show that the flow of the cell material may be broadly divided into macroscopic flow perpendicular to the compression direction and jetting-type processes (microkinetic flow) which tend to predominate in rod and rodlike configurations and also tend to play an increasing role at increased strain rates. A very simple analysis of a configuration in which a solid flyer impacts a solid target provides a baseline against which to compare and explain features seen in the simulations. The work provides a basis for the development of energy absorbing structures for application in the 200-1000 m/s impact regime.

  13. Resolution of Infinite-Loop in Hyperincursive and Nonlocal Cellular Automata: Introduction to Slime Mold Computing

    NASA Astrophysics Data System (ADS)

    Aono, Masashi; Gunji, Yukio-Pegio

    2004-08-01

    How can non-algorithmic/non-deterministic computational syntax be computed? "The hyperincursive system" introduced by Dubois is an anticipatory system embracing the contradiction/uncertainty. Although it may provide a novel viewpoint for the understanding of complex systems, conventional digital computers cannot run faithfully as the hyperincursive computational syntax specifies, in a strict sense. Then is it an imaginary story? In this paper we try to argue that it is not. We show that a model of complex systems "Elementary Conflictable Cellular Automata (ECCA)" proposed by Aono and Gunji is embracing the hyperincursivity and the nonlocality. ECCA is based on locality-only type settings basically as well as other CA models, and/but at the same time, each cell is required to refer to globality-dominant regularity. Due to this contradictory locality-globality loop, the time evolution equation specifies that the system reaches the deadlock/infinite-loop. However, we show that there is a possibility of the resolution of these problems if the computing system has parallel and/but non-distributed property like an amoeboid organism. This paper is an introduction to "the slime mold computing" that is an attempt to cultivate an unconventional notion of computation.

  14. Cellular resolution models for even skipped regulation in the entire Drosophila embryo.

    PubMed

    Ilsley, Garth R; Fisher, Jasmin; Apweiler, Rolf; De Pace, Angela H; Luscombe, Nicholas M

    2013-08-06

    Transcriptional control ensures genes are expressed in the right amounts at the correct times and locations. Understanding quantitatively how regulatory systems convert input signals to appropriate outputs remains a challenge. For the first time, we successfully model even skipped (eve) stripes 2 and 3+7 across the entire fly embryo at cellular resolution. A straightforward statistical relationship explains how transcription factor (TF) concentrations define eve's complex spatial expression, without the need for pairwise interactions or cross-regulatory dynamics. Simulating thousands of TF combinations, we recover known regulators and suggest new candidates. Finally, we accurately predict the intricate effects of perturbations including TF mutations and misexpression. Our approach imposes minimal assumptions about regulatory function; instead we infer underlying mechanisms from models that best fit the data, like the lack of TF-specific thresholds and the positional value of homotypic interactions. Our study provides a general and quantitative method for elucidating the regulation of diverse biological systems. DOI:http://dx.doi.org/10.7554/eLife.00522.001.

  15. Functional clustering of neurons in motor cortex determined by cellular resolution imaging in awake behaving mice

    PubMed Central

    Dombeck, Daniel A.; Graziano, Michael S.; Tank, David W.

    2010-01-01

    Macroscopic (millimeter scale) functional clustering is a hallmark characteristic of motor cortex spatial organization in awake behaving mammals; however, almost no information is known about the functional micro-organization (~100 microns scale). Here, we optically recorded intracellular calcium transients of layer 2/3 neurons with cellular resolution over ~200 micron diameter fields in the forelimb motor cortex of mobile, head-restrained mice during two distinct movements (running and grooming). We showed that the temporal correlation between neurons was statistically larger the closer the neurons were to each other. We further explored this correlation by using two separate methods to spatially segment the neurons within each imaging field: K-means clustering and correlations between single neuron activity and mouse movements. The two methods segmented the neurons similarly and led to the conclusion that the origin of the inverse relationship between correlation and distance seen statistically was two-fold: clusters of highly temporally correlated neurons were often spatially distinct from one another and (even when the clusters were spatially intermingled) within the clusters, the more correlated the neurons were to each other, the shorter the distance between them. Our results represent a direct observation of functional clustering within the micro-circuitry of the awake mouse motor cortex. PMID:19889987

  16. High-resolution CMOS MEA platform to study neurons at subcellular, cellular, and network levels.

    PubMed

    Müller, Jan; Ballini, Marco; Livi, Paolo; Chen, Yihui; Radivojevic, Milos; Shadmani, Amir; Viswam, Vijay; Jones, Ian L; Fiscella, Michele; Diggelmann, Roland; Stettler, Alexander; Frey, Urs; Bakkum, Douglas J; Hierlemann, Andreas

    2015-07-07

    Studies on information processing and learning properties of neuronal networks would benefit from simultaneous and parallel access to the activity of a large fraction of all neurons in such networks. Here, we present a CMOS-based device, capable of simultaneously recording the electrical activity of over a thousand cells in in vitro neuronal networks. The device provides sufficiently high spatiotemporal resolution to enable, at the same time, access to neuronal preparations on subcellular, cellular, and network level. The key feature is a rapidly reconfigurable array of 26 400 microelectrodes arranged at low pitch (17.5 μm) within a large overall sensing area (3.85 × 2.10 mm(2)). An arbitrary subset of the electrodes can be simultaneously connected to 1024 low-noise readout channels as well as 32 stimulation units. Each electrode or electrode subset can be used to electrically stimulate or record the signals of virtually any neuron on the array. We demonstrate the applicability and potential of this device for various different experimental paradigms: large-scale recordings from whole networks of neurons as well as investigations of axonal properties of individual neurons.

  17. Impact of Resolution on Simulation of Closed Mesoscale Cellular Convection Identified by Dynamically Guided Watershed Segmentation

    SciTech Connect

    Martini, Matus N.; Gustafson, William I.; Yang, Qing; Xiao, Heng

    2014-11-18

    Organized mesoscale cellular convection (MCC) is a common feature of marine stratocumulus that forms in response to a balance between mesoscale dynamics and smaller scale processes such as cloud radiative cooling and microphysics. We use the Weather Research and Forecasting model with chemistry (WRF-Chem) and fully coupled cloud-aerosol interactions to simulate marine low clouds during the VOCALS-REx campaign over the southeast Pacific. A suite of experiments with 3- and 9-km grid spacing indicates resolution-dependent behavior. The simulations with finer grid spacing have smaller liquid water paths and cloud fractions, while cloud tops are higher. The observed diurnal cycle is reasonably well simulated. To isolate organized MCC characteristics we develop a new automated method, which uses a variation of the watershed segmentation technique that combines the detection of cloud boundaries with a test for coincident vertical velocity characteristics. This ensures that the detected cloud fields are dynamically consistent for closed MCC, the most common MCC type over the VOCALS-REx region. We demonstrate that the 3-km simulation is able to reproduce the scaling between horizontal cell size and boundary layer height seen in satellite observations. However, the 9-km simulation is unable to resolve smaller circulations corresponding to shallower boundary layers, instead producing invariant MCC horizontal scale for all simulated boundary layers depths. The results imply that climate models with grid spacing of roughly 3 km or smaller may be needed to properly simulate the MCC structure in the marine stratocumulus regions.

  18. The functional micro-organization of grid cells revealed by cellular-resolution imaging

    PubMed Central

    Heys, James G.; Rangarajan, Krsna V.; Dombeck, Daniel A.

    2015-01-01

    Summary Establishing how grid cells are anatomically arranged, on a microscopic scale, in relation to their firing patterns in the environment would facilitate a greater micro-circuit level understanding of the brain’s representation of space. However, all previous grid cell recordings used electrode techniques that provide limited descriptions of fine-scale organization. We therefore developed a technique for cellular-resolution functional imaging of medial entorhinal cortex (MEC) neurons in mice navigating a virtual linear track, enabling a new experimental approach to study MEC. Using these methods, we show that grid cells are physically clustered in MEC compared to non-grid cells. Additionally, we demonstrate that grid cells are functionally micro-organized: The similarity between the environment firing locations of grid cell pairs varies as a function of the distance between them according to a “Mexican Hat” shaped profile. This suggests that, on average, nearby grid cells have more similar spatial firing phases than those further apart. PMID:25467986

  19. Cellular resolution models for even skipped regulation in the entire Drosophila embryo

    PubMed Central

    Ilsley, Garth R; Fisher, Jasmin; Apweiler, Rolf; DePace, Angela H; Luscombe, Nicholas M

    2013-01-01

    Transcriptional control ensures genes are expressed in the right amounts at the correct times and locations. Understanding quantitatively how regulatory systems convert input signals to appropriate outputs remains a challenge. For the first time, we successfully model even skipped (eve) stripes 2 and 3+7 across the entire fly embryo at cellular resolution. A straightforward statistical relationship explains how transcription factor (TF) concentrations define eve’s complex spatial expression, without the need for pairwise interactions or cross-regulatory dynamics. Simulating thousands of TF combinations, we recover known regulators and suggest new candidates. Finally, we accurately predict the intricate effects of perturbations including TF mutations and misexpression. Our approach imposes minimal assumptions about regulatory function; instead we infer underlying mechanisms from models that best fit the data, like the lack of TF-specific thresholds and the positional value of homotypic interactions. Our study provides a general and quantitative method for elucidating the regulation of diverse biological systems. DOI: http://dx.doi.org/10.7554/eLife.00522.001 PMID:23930223

  20. Dielectric elastomer actuator for the measurement of cell traction forces with sub-cellular resolution

    NASA Astrophysics Data System (ADS)

    Rosset, Samuel; Poulin, Alexandre; Zollinger, Alicia; Smith, Michael; Shea, Herbert

    2017-04-01

    We report on the use of dielectric elastomer actuators (DEAs) to measure the traction force field of cells with subcellular resolution. The study of cellular electrochemical and mechanical response to deformation is an important area of research, as mechanotransduction has been shown to be linked with fundamental cell functions, or the progression of diseases such as cancer or atherosclerosis. Experimental cell mechanics is based on two fundamental concepts: the ability to measure cell stiffness, and to apply controlled strains to small clusters of cells. However, there is a lack of tools capable of applying precise deformation to a small cell population while being compatible with an inverted microscope (stable focal plane, transparency, compactness, etc.). Here, we use an anisotropically prestretched silicone-based DEA to deform a soft (7.6kPa) polyacrylamide gel on which the cells are cultured. An array of micro-dots of fluorescent fibronectin is transferred on the gel by micro-contact printing and serves as attachment points for the cells. In addition, the fluorescent dots (which have a diameter of 2 μm with a spacing of 6 μm) are used during the experiment to monitor the traction forces of a single cell (or small cluster of cells). The cell locally exerts traction on the gel, thus deforming the matrix of dots. The position of dots versus time is monitored live when the cells are submitted to a uniaxial strain step. Our deformable bioreactor enables the measurement of the local stiffness of cells submitted to mechanical strain, and is fully compatible with an inverted microscope set-up.

  1. Snapshot Hyperspectral Volumetric Microscopy

    PubMed Central

    Wu, Jiamin; Xiong, Bo; Lin, Xing; He, Jijun; Suo, Jinli; Dai, Qionghai

    2016-01-01

    The comprehensive analysis of biological specimens brings about the demand for capturing the spatial, temporal and spectral dimensions of visual information together. However, such high-dimensional video acquisition faces major challenges in developing large data throughput and effective multiplexing techniques. Here, we report the snapshot hyperspectral volumetric microscopy that computationally reconstructs hyperspectral profiles for high-resolution volumes of ~1000 μm × 1000 μm × 500 μm at video rate by a novel four-dimensional (4D) deconvolution algorithm. We validated the proposed approach with both numerical simulations for quantitative evaluation and various real experimental results on the prototype system. Different applications such as biological component analysis in bright field and spectral unmixing of multiple fluorescence are demonstrated. The experiments on moving fluorescent beads and GFP labelled drosophila larvae indicate the great potential of our method for observing multiple fluorescent markers in dynamic specimens. PMID:27103155

  2. Snapshot Hyperspectral Volumetric Microscopy

    NASA Astrophysics Data System (ADS)

    Wu, Jiamin; Xiong, Bo; Lin, Xing; He, Jijun; Suo, Jinli; Dai, Qionghai

    2016-04-01

    The comprehensive analysis of biological specimens brings about the demand for capturing the spatial, temporal and spectral dimensions of visual information together. However, such high-dimensional video acquisition faces major challenges in developing large data throughput and effective multiplexing techniques. Here, we report the snapshot hyperspectral volumetric microscopy that computationally reconstructs hyperspectral profiles for high-resolution volumes of ~1000 μm × 1000 μm × 500 μm at video rate by a novel four-dimensional (4D) deconvolution algorithm. We validated the proposed approach with both numerical simulations for quantitative evaluation and various real experimental results on the prototype system. Different applications such as biological component analysis in bright field and spectral unmixing of multiple fluorescence are demonstrated. The experiments on moving fluorescent beads and GFP labelled drosophila larvae indicate the great potential of our method for observing multiple fluorescent markers in dynamic specimens.

  3. Slow Growing Volumetric Subdivision for 3D Volumetric Data

    SciTech Connect

    Pascucci, V; Kahn, S; Kelley, R; Kilbourne, C; Porter, F; Wargelin, B

    2004-12-16

    In recent years subdivision methods have been successfully applied to the multi-resolution representation and compression of surface meshes. Unfortunately their use in the volumetric case has remained impractical because of the use of tensor-product generalizations that induce an excessive growth of the mesh size before sufficient number is preformed. This technical sketch presents a new subdivision technique that refines volumetric (and higher-dimensional) meshes at the same rate of surface meshes. The scheme builds adaptive refinements of a mesh without using special decompositions of the cells connecting different levels of resolution. Lower dimensional ''sharp'' features are also handled directly in a natural way. The averaging rules allow to reproduce the same smoothness of the two best known previous tensor product refinement methods.

  4. Multi-resolution 3D visualization of the early stages of cellular uptake of peptide-coated nanoparticles

    DOE PAGES

    Welsher, Kevin; Yang, Haw

    2014-02-23

    A detailed understanding of the cellular uptake process is essential to the development of cellular delivery strategies and to the study of viral trafficking. However, visualization of the entire process, encompassing the fast dynamics (local to the freely diffusing nanoparticle) as well the state of the larger-scale cellular environment, remains challenging. Here, we introduce a three-dimensional multi-resolution method to capture, in real time, the transient events leading to cellular binding and uptake of peptide (HIV1-Tat)-modified nanoparticles. Applying this new method to observe the landing of nanoparticles on the cellular contour in three dimensions revealed long-range deceleration of the delivery particle,more » possibly due to interactions with cellular receptors. Furthermore, by using the nanoparticle as a nanoscale ‘dynamics pen’, we discovered an unexpected correlation between small membrane terrain structures and local nanoparticle dynamics. This approach could help to reveal the hidden mechanistic steps in a variety of multiscale processes.« less

  5. Volumetric Combustion Diagnostics

    DTIC Science & Technology

    2017-01-03

    VLIF), 4) the investigation and validation of Volumetric Particle Image Velocimetry (VPIV), 5) the use of fiber bundles in volumetric tomography, and 6...Volumetric Laser Induced Fluorescence (VLIF)………………………………………… 6 2.4. Volumetric Particle Image Velocimetry (VPIV)………………………………………… 9 2.5. Use of Fiber...underway. 4. Volumetric Particle Image Velocimetry (VPIV) This objective was partially completed and will continue into the second year. We have

  6. Three-dimensional morphology and gene expression in the Drosophila blastoderm at cellular resolution I: data acquisition pipeline

    PubMed Central

    Luengo Hendriks, Cris L; Keränen, Soile VE; Fowlkes, Charless C; Simirenko, Lisa; Weber, Gunther H; DePace, Angela H; Henriquez, Clara; Kaszuba, David W; Hamann, Bernd; Eisen, Michael B; Malik, Jitendra; Sudar, Damir; Biggin, Mark D; Knowles, David W

    2006-01-01

    Background To model and thoroughly understand animal transcription networks, it is essential to derive accurate spatial and temporal descriptions of developing gene expression patterns with cellular resolution. Results Here we describe a suite of methods that provide the first quantitative three-dimensional description of gene expression and morphology at cellular resolution in whole embryos. A database containing information derived from 1,282 embryos is released that describes the mRNA expression of 22 genes at multiple time points in the Drosophila blastoderm. We demonstrate that our methods are sufficiently accurate to detect previously undescribed features of morphology and gene expression. The cellular blastoderm is shown to have an intricate morphology of nuclear density patterns and apical/basal displacements that correlate with later well-known morphological features. Pair rule gene expression stripes, generally considered to specify patterning only along the anterior/posterior body axis, are shown to have complex changes in stripe location, stripe curvature, and expression level along the dorsal/ventral axis. Pair rule genes are also found to not always maintain the same register to each other. Conclusion The application of these quantitative methods to other developmental systems will likely reveal many other previously unknown features and provide a more rigorous understanding of developmental regulatory networks. PMID:17184546

  7. Multiplexed 3D cellular super-resolution imaging with DNA-PAINT and Exchange-PAINT.

    PubMed

    Jungmann, Ralf; Avendaño, Maier S; Woehrstein, Johannes B; Dai, Mingjie; Shih, William M; Yin, Peng

    2014-03-01

    Super-resolution fluorescence microscopy is a powerful tool for biological research, but obtaining multiplexed images for a large number of distinct target species remains challenging. Here we use the transient binding of short fluorescently labeled oligonucleotides (DNA-PAINT, a variation of point accumulation for imaging in nanoscale topography) for simple and easy-to-implement multiplexed super-resolution imaging that achieves sub-10-nm spatial resolution in vitro on synthetic DNA structures. We also report a multiplexing approach (Exchange-PAINT) that allows sequential imaging of multiple targets using only a single dye and a single laser source. We experimentally demonstrate ten-color super-resolution imaging in vitro on synthetic DNA structures as well as four-color two-dimensional (2D) imaging and three-color 3D imaging of proteins in fixed cells.

  8. Multiplexed 3D Cellular Super-Resolution Imaging with DNA-PAINT and Exchange-PAINT

    PubMed Central

    Jungmann, R.; Avendano, M.S.; Woehrstein, J.B.; Dai, M.; Shih, W.M.; Yin, P.

    2014-01-01

    While super-resolution fluorescence microscopy is a powerful tool for biological research, obtaining multiplexed images for a large number of distinct target species remains challenging. Here we use the transient binding of short fluorescently labeled oligonucleotides (DNA-PAINT, point accumulation for imaging in nanoscale topography) for simple and easy-to-implement multiplexed 3D super-resolution imaging inside fixed cells and achieve sub-10 nm spatial resolution in vitro using synthetic DNA structures. We also report a novel approach for multiplexing (Exchange-PAINT) that allows sequential imaging of multiple targets using only a single dye and a single laser source. We experimentally demonstrate ten-“color” super-resolution imaging in vitro on synthetic DNA structures and four-“color” imaging of proteins in a fixed cell. PMID:24487583

  9. The Limit of Resolution and Detectability of the ArcCHECK QA Phantom in small field Volumetric Modulated Arc Therapy and Stereotactic Radiosurgery Quality Assurance

    NASA Astrophysics Data System (ADS)

    Gray, Tara

    Purpose: To determine the limit of detectability and resolution of the ArcCheck QA Phantom (Sun Nuclear, Inc.) for quality assurance of volumetric-modulated arc therapy and stereotactic radiosurgery procedures when used in small field sizes. Methods: Eight different square field sizes (0.6x0.6, 1x1, 2x2, 3x3, 5x5, 7x7, 10x10, 15x15 cm2) were measured on the ArcCheck QA phantom at three different gantry angles: 0, 90, and 270 degrees, using a 6 MV beam at its maximum dose rate of 600 MU/min and a dose computed from a 200 MU beam from the Varian Edge linear accelerator (Varian Medical Systems, Palo Alto, CA) at the University of Toledo Dana Cancer Center. Four different types of errors were introduced into quality-assurance analysis procedures. Measured square field sizes were compared against the same measured square field sizes with induced collimator and MLC errors. Induced collimator errors were defined by an expansion of the jaw-defined field size by 1 mm on all axes, a collimator shift of 1 mm on the X2 and Y2 axes, a table shift by 1 mm vertically and longitudinally at 270 and 90 degrees and a table shift of 1mm laterally and longitudinally for angles of 0 and 180 degrees. MLC induced errors included the addition of one and subsequently two opposing MLC leaves in the center of each square field. Dose distributions for the normal square fields and square fields with induced errors were imported into SNC patient software (Sun Nuclear Corporation, Melbourne, FL) in the form of DICOM RT dose files and measured dose distributions were compared between the normally measured square fields and fields containing induced errors. Percent pass rates were computed using gamma analysis criteria of 2 mm/2% with a threshold value of 20%. Point dose ratios were also analyzed for fields with induced MLC errors and output factors were calculated in order to determine the magnitude of the effect that these induced errors had on output measurements as compared with the ability of

  10. A novel optical microscope for imaging large embryos and tissue volumes with sub-cellular resolution throughout

    PubMed Central

    McConnell, Gail; Trägårdh, Johanna; Amor, Rumelo; Dempster, John; Reid, Es; Amos, William Bradshaw

    2016-01-01

    Current optical microscope objectives of low magnification have low numerical aperture and therefore have too little depth resolution and discrimination to perform well in confocal and nonlinear microscopy. This is a serious limitation in important areas, including the phenotypic screening of human genes in transgenic mice by study of embryos undergoing advanced organogenesis. We have built an optical lens system for 3D imaging of objects up to 6 mm wide and 3 mm thick with depth resolution of only a few microns instead of the tens of microns currently attained, allowing sub-cellular detail to be resolved throughout the volume. We present this lens, called the Mesolens, with performance data and images from biological specimens including confocal images of whole fixed and intact fluorescently-stained 12.5-day old mouse embryos. DOI: http://dx.doi.org/10.7554/eLife.18659.001 PMID:27661778

  11. Genetic code expansion enables live-cell and super-resolution imaging of site-specifically labeled cellular proteins.

    PubMed

    Uttamapinant, Chayasith; Howe, Jonathan D; Lang, Kathrin; Beránek, Václav; Davis, Lloyd; Mahesh, Mohan; Barry, Nicholas P; Chin, Jason W

    2015-04-15

    Methods to site-specifically and densely label proteins in cellular ultrastructures with small, bright, and photostable fluorophores would substantially advance super-resolution imaging. Recent advances in genetic code expansion and bioorthogonal chemistry have enabled the site-specific labeling of proteins. However, the efficient incorporation of unnatural amino acids into proteins and the specific, fluorescent labeling of the intracellular ultrastructures they form for subdiffraction imaging has not been accomplished. Two challenges have limited progress in this area: (i) the low efficiency of unnatural amino acid incorporation that limits labeling density and therefore spatial resolution and (ii) the uncharacterized specificity of intracellular labeling that will define signal-to-noise, and ultimately resolution, in imaging. Here we demonstrate the efficient production of cystoskeletal proteins (β-actin and vimentin) containing bicyclo[6.1.0]nonyne-lysine at genetically defined sites. We demonstrate their selective fluorescent labeling with respect to the proteome of living cells using tetrazine-fluorophore conjugates, creating densely labeled cytoskeletal ultrastructures. STORM imaging of these densely labeled ultrastructures reveals subdiffraction features, including nuclear actin filaments. This work enables the site-specific, live-cell, fluorescent labeling of intracellular proteins at high density for super-resolution imaging of ultrastructural features within cells.

  12. Nuclear protein accumulation in cellular senescence and organismal aging revealed with a novel single-cell resolution fluorescence microscopy assay.

    PubMed

    De Cecco, Marco; Jeyapalan, Jessie; Zhao, Xiaoai; Tamamori-Adachi, Mimi; Sedivy, John M

    2011-10-01

    Replicative cellular senescence was discovered some 50 years ago. The phenotypes of senescent cells have been investigated extensively in cell culture, and found to affect essentially all aspects of cellular physiology. The relevance of cellular senescence in the context of age-associated pathologies as well as normal aging is a topic of active and ongoing interest. Considerable effort has been devoted to biomarker discovery to enable the microscopic detection of single senescent cells in tissues. One characteristic of senescent cells documented very early in cell culture studies was an increase in cell size and total protein content, but whether this occurs in vivo is not known. A limiting factor for studies of protein content and localization has been the lack of suitable fluorescence microscopy tools. We have developed an easy and flexible method, based on the merocyanine dye known as NanoOrange, to visualize and quantitatively measure total protein levels by high resolution fluorescence microscopy. NanoOrange staining can be combined with antibody-based immunofluorescence, thus providing both specific target and total protein information in the same specimen. These methods are optimally combined with automated image analysis platforms for high throughput analysis. We document here increasing protein content and density in nuclei of senescent human and mouse fibroblasts in vitro, and in liver nuclei of aged mice in vivo. Additionally, in aged liver nuclei NanoOrange revealed protein-dense foci that colocalize with centromeric heterochromatin.

  13. Revealing the cellular localization of STAT1 during the cell cycle by super-resolution imaging

    NASA Astrophysics Data System (ADS)

    Gao, Jing; Wang, Feng; Liu, Yanhou; Cai, Mingjun; Xu, Haijiao; Jiang, Junguang; Wang, Hongda

    2015-03-01

    Signal transducers and activators of transcription (STATs) can transduce cytokine signals and regulate gene expression. The cellular localization and nuclear trafficking of STAT1, a representative of the STAT family with multiple transcriptional functions, is tightly related with transcription process, which usually happens in the interphase of the cell cycle. However, these priority questions regarding STAT1 distribution and localization at the different cell-cycle stages remain unclear. By using direct stochastic optical reconstruction microscopy (dSTORM), we found that the nuclear expression level of STAT1 increased gradually as the cell cycle carried out, especially after EGF stimulation. Furthermore, STAT1 formed clusters in the whole cell during the cell cycle, with the size and the number of clusters also increasing significantly from G1 to G2 phase, suggesting that transcription and other cell-cycle related activities can promote STAT1 to form more and larger clusters for fast response to signals. Our work reveals that the cellular localization and clustering distribution of STAT1 are associated with the cell cycle, and further provides an insight into the mechanism of cell-cycle regulated STAT1 signal transduction.

  14. In vivo near-realtime volumetric optical-resolution photoacoustic microscopy using a high-repetition-rate nanosecond fiber-laser

    NASA Astrophysics Data System (ADS)

    Shi, Wei; Hajireza, Parsin; Shao, Peng; Forbrich, Alexander; Zemp, Roger J.

    2011-08-01

    Optical-resolution photoacoustic microscopy (OR-PAM) is capable of achieving optical-absorption-contrast images with micron-scale spatial resolution. Previous OR-PAM systems have been frame-rate limited by mechanical scanning speeds and laser pulse repetition rate (PRR). We demonstrate OR-PAM imaging using a diode-pumped nanosecond-pulsed Ytterbium-doped 532-nm fiber laser with PRR up to 600 kHz. Combined with fast-scanning mirrors, our proposed system provides C-scan and 3D images with acquisition frame rate of 4 frames per second (fps) or higher, two orders of magnitude faster than previously published systems. High-contrast images of capillary-scale microvasculature in a live Swiss Webster mouse ear with ~6-μm optical lateral spatial resolution are demonstrated.

  15. Cellular resolution circuit mapping with temporal-focused excitation of soma-targeted channelrhodopsin

    PubMed Central

    Baker, Christopher A; Elyada, Yishai M; Parra, Andres; Bolton, M McLean

    2016-01-01

    We describe refinements in optogenetic methods for circuit mapping that enable measurements of functional synaptic connectivity with single-neuron resolution. By expanding a two-photon beam in the imaging plane using the temporal focusing method and restricting channelrhodopsin to the soma and proximal dendrites, we are able to reliably evoke action potentials in individual neurons, verify spike generation with GCaMP6s, and determine the presence or absence of synaptic connections with patch-clamp electrophysiological recording. DOI: http://dx.doi.org/10.7554/eLife.14193.001 PMID:27525487

  16. Cellular resolution optical access to brain regions in fissures: imaging medial prefrontal cortex and grid cells in entorhinal cortex.

    PubMed

    Low, Ryan J; Gu, Yi; Tank, David W

    2014-12-30

    In vivo two-photon microscopy provides the foundation for an array of powerful techniques for optically measuring and perturbing neural circuits. However, challenging tissue properties and geometry have prevented high-resolution optical access to regions situated within deep fissures. These regions include the medial prefrontal and medial entorhinal cortex (mPFC and MEC), which are of broad scientific and clinical interest. Here, we present a method for in vivo, subcellular resolution optical access to the mPFC and MEC using microprisms inserted into the fissures. We chronically imaged the mPFC and MEC in mice running on a spherical treadmill, using two-photon laser-scanning microscopy and genetically encoded calcium indicators to measure network activity. In the MEC, we imaged grid cells, a widely studied cell type essential to memory and spatial information processing. These cells exhibited spatially modulated activity during navigation in a virtual reality environment. This method should be extendable to other brain regions situated within deep fissures, and opens up these regions for study at cellular resolution in behaving animals using a rapidly expanding palette of optical tools for perturbing and measuring network structure and function.

  17. Functional imaging of hippocampal place cells at cellular resolution during virtual navigation.

    PubMed

    Dombeck, Daniel A; Harvey, Christopher D; Tian, Lin; Looger, Loren L; Tank, David W

    2010-11-01

    Spatial navigation is often used as a behavioral task in studies of the neuronal circuits that underlie cognition, learning and memory in rodents. The combination of in vivo microscopy with genetically encoded indicators has provided an important new tool for studying neuronal circuits, but has been technically difficult to apply during navigation. Here we describe methods for imaging the activity of neurons in the CA1 region of the hippocampus with subcellular resolution in behaving mice. Neurons that expressed the genetically encoded calcium indicator GCaMP3 were imaged through a chronic hippocampal window. Head-restrained mice performed spatial behaviors in a setup combining a virtual reality system and a custom-built two-photon microscope. We optically identified populations of place cells and determined the correlation between the location of their place fields in the virtual environment and their anatomical location in the local circuit. The combination of virtual reality and high-resolution functional imaging should allow a new generation of studies to investigate neuronal circuit dynamics during behavior.

  18. Functional imaging with cellular resolution reveals precise micro-architecture in visual cortex

    NASA Astrophysics Data System (ADS)

    Ohki, Kenichi; Chung, Sooyoung; Ch'ng, Yeang H.; Kara, Prakash; Reid, R. Clay

    2005-02-01

    Neurons in the cerebral cortex are organized into anatomical columns, with ensembles of cells arranged from the surface to the white matter. Within a column, neurons often share functional properties, such as selectivity for stimulus orientation; columns with distinct properties, such as different preferred orientations, tile the cortical surface in orderly patterns. This functional architecture was discovered with the relatively sparse sampling of microelectrode recordings. Optical imaging of membrane voltage or metabolic activity elucidated the overall geometry of functional maps, but is averaged over many cells (resolution >100µm). Consequently, the purity of functional domains and the precision of the borders between them could not be resolved. Here, we labelled thousands of neurons of the visual cortex with a calcium-sensitive indicator in vivo. We then imaged the activity of neuronal populations at single-cell resolution with two-photon microscopy up to a depth of 400µm. In rat primary visual cortex, neurons had robust orientation selectivity but there was no discernible local structure; neighbouring neurons often responded to different orientations. In area 18 of cat visual cortex, functional maps were organized at a fine scale. Neurons with opposite preferences for stimulus direction were segregated with extraordinary spatial precision in three dimensions, with columnar borders one to two cells wide. These results indicate that cortical maps can be built with single-cell precision.

  19. Fully automated cellular-resolution vertebrate screening platform with parallel animal processing.

    PubMed

    Chang, Tsung-Yao; Pardo-Martin, Carlos; Allalou, Amin; Wählby, Carolina; Yanik, Mehmet Fatih

    2012-02-21

    The zebrafish larva is an optically-transparent vertebrate model with complex organs that is widely used to study genetics, developmental biology, and to model various human diseases. In this article, we present a set of novel technologies that significantly increase the throughput and capabilities of our previously described vertebrate automated screening technology (VAST). We developed a robust multi-thread system that can simultaneously process multiple animals. System throughput is limited only by the image acquisition speed rather than by the fluidic or mechanical processes. We developed image recognition algorithms that fully automate manipulation of animals, including orienting and positioning regions of interest within the microscope's field of view. We also identified the optimal capillary materials for high-resolution, distortion-free, low-background imaging of zebrafish larvae.

  20. Fully automated cellular-resolution vertebrate screening platform with parallel animal processing

    PubMed Central

    Chang, Tsung-Yao; Pardo-Martin, Carlos; Allalou, Amin; Wählby, Carolina; Yanik, Mehmet Fatih

    2012-01-01

    The zebrafish larva is an optically-transparent vertebrate model with complex organs that is widely used to study genetics, developmental biology, and to model various human diseases. In this article, we present a set of novel technologies that significantly increase the throughput and capabilities of previously described vertebrate automated screening technology (VAST). We developed a robust multi-thread system that can simultaneously process multiple animals. System throughput is limited only by the image acquisition speed rather than by the fluidic or mechanical processes. We developed image recognition algorithms that fully automate manipulation of animals, including orienting and positioning regions of interest within the microscope’s field of view. We also identified the optimal capillary materials for high-resolution, distortion-free, low-background imaging of zebrafish larvae. PMID:22159032

  1. High-resolution adaptive optics retinal imaging of cellular structure in choroideremia.

    PubMed

    Morgan, Jessica I W; Han, Grace; Klinman, Eva; Maguire, William M; Chung, Daniel C; Maguire, Albert M; Bennett, Jean

    2014-09-04

    We characterized retinal structure in patients and carriers of choroideremia using adaptive optics and other high resolution modalities. A total of 57 patients and 18 carriers of choroideremia were imaged using adaptive optics scanning light ophthalmoscopy (AOSLO), optical coherence tomography (OCT), autofluorescence (AF), and scanning light ophthalmoscopy (SLO). Cone density was measured in 59 eyes of 34 patients where the full cone mosaic was observed. The SLO imaging revealed scalloped edges of RPE atrophy and large choroidal vessels. The AF imaging showed hypo-AF in areas of degeneration, while central AF remained present. OCT images showed outer retinal tubulations and thinned RPE/interdigitation layers. The AOSLO imaging revealed the cone mosaic in central relatively intact retina, and cone density was either reduced or normal at 0.5 mm eccentricity. The border of RPE atrophy showed abrupt loss of the cone mosaic at the same location. The AF imaging in comparison with AOSLO showed RPE health may be compromised before cone degeneration. Other disease features, including visualization of choroidal vessels, hyper-reflective clumps of cones, and unique retinal findings, were tabulated to show the frequency of occurrence and model disease progression. The data support the RPE being one primary site of degeneration in patients with choroideremia. Photoreceptors also may degenerate independently. High resolution imaging, particularly AOSLO in combination with OCT, allows single cell analysis of disease in choroideremia. These modalities promise to be useful in monitoring disease progression, and in documenting the efficacy of gene and cell-based therapies for choroideremia and other diseases as these therapies emerge. (ClinicalTrials.gov number, NCT01866371.). Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  2. Mechanism of cellular secretion studied by high resolution soft-x-ray microscopy

    SciTech Connect

    Loo, Jr., Billy W.; Meyer-Ilse, W; Rothman, S S

    1997-04-01

    The secretion of proteins is a fundamental cellular process. The physical and biochemical mechanisms that underlie this process have been studied with the view that they can serve as a general model for how cells transport many different substances to and through their various compartments and to the external environment. In this work, the authors study the secretion of digestive enzymes by the acinar cell of the mammalian pancreas. This is the classical system for studying such processes. The proteins that digest food are stored in approximately micrometer sized vesicles, zymogen granules, within these cells. There are two explanations for how these proteins are transported from within the granules to the exterior of the cell during the process of secretion. One proposes that whole granules are lost from the cell in discrete events, and the other proposes that partial and gradual emptying of the granules accounts for protein secretion. Of course, both mechanisms may occur. The authors are attempting to assess to what degree each of these mechanisms account for protein secretion by the organ. In order to do so, the authors have been determining whether physical changes in the granules, such as mass loss, occur during secretion as the second model predicts, or if there is a simple reduction in the number of granules as predicted by the first model.

  3. Single-view volumetric PIV via high-resolution scanning, isotropic voxel restructuring and 3D least-squares matching (3D-LSM)

    NASA Astrophysics Data System (ADS)

    Brücker, C.; Hess, D.; Kitzhofer, J.

    2013-02-01

    Scanning PIV as introduced by Brücker (1995 Exp. Fluids 19 255-63, 1996a Appl. Sci. Res. 56 157-79) has been successfully applied in the last 20 years to different flow problems where the frame rate was sufficient to ensure a ‘frozen’ field condition. The limited number of parallel planes however leads typically to an under-sampling in the scan direction in depth; therefore, the spatial resolution in depth is typically considerably lower than the spatial resolution in the plane of the laser sheet (depth resolution = scan shift Δz ≫ pixel unit in object space). In addition, a partial volume averaging effect due to the thickness of the light sheet must be taken into account. Herein, the method is further developed using a high-resolution scanning in combination with a Gaussian regression technique to achieve an isotropic representation of the tracer particles in a voxel-based volume reconstruction with cuboidal voxels. This eliminates the partial volume averaging effect due to light sheet thickness and leads to comparable spatial resolution of the particle field reconstructions in x-, y- and z-axes. In addition, advantage of voxel-based processing with estimations of translation, rotation and shear/strain is taken by using a 3D least-squares matching method, well suited for reconstruction of grey-level pattern fields. The method is discussed in this paper and used to investigate the ring vortex instability at Re = 2500 within a measurement volume of roughly 75 × 75 × 50 mm3 with a spatial resolution of 100 µm/voxel (750 × 750 × 500 voxel elements). The volume has been scanned with a number of 100 light sheets and scan rates of 10 kHz. The results show the growth of the Tsai-Widnall azimuthal instabilities accompanied with a precession of the axis of the vortex ring. Prior to breakdown, secondary instabilities evolve along the core with streamwise oriented striations. The front stagnation point's streamwise distance to the core starts to decrease while

  4. Sponge grade body fossil with cellular resolution dating 60 Myr before the Cambrian.

    PubMed

    Yin, Zongjun; Zhu, Maoyan; Davidson, Eric H; Bottjer, David J; Zhao, Fangchen; Tafforeau, Paul

    2015-03-24

    An extraordinarily well preserved, 600-million-year (Myr)-old, three-dimensionally phosphatized fossil displaying multiple independent characters of modern adult sponges has been analyzed by SEM and synchrotron X-ray tomography. The fossilized animal (Eocyathispongia qiania gen. et sp. nov.) is slightly more than 1.2 mm wide and 1.1 mm tall, is composed of hundreds of thousands of cells, and has a gross structure consisting of three adjacent hollow tubes sharing a common base. The main tube is crowned with a large open funnel, and the others end in osculum-like openings to the exterior. The external surface is densely covered with flat tile-like cells closely resembling sponge pinacocytes, and this layer is punctuated with smaller pores. A dense patch of external structures that display the form of a lawn of sponge papillae has also survived. Within the main funnel, an area where features of the inner surface are preserved displays a regular pattern of uniform pits. Many of them are surrounded individually by distinct collars, mounted in a supporting reticulum. The possibility cannot be excluded that these pits are the remains of a field of choanocytes. The character set evinced by this specimen, ranging from general anatomy to cell type, uniquely indicates that this specimen is a fossil of probable poriferan affinity. So far, we have only this single specimen, and although its organized and complex cellular structure precludes any reasonable interpretation that its origin is abiogenic, confirmation that it is indeed a fossilized sponge will clearly require discovery of additional specimens.

  5. Sponge grade body fossil with cellular resolution dating 60 Myr before the Cambrian

    PubMed Central

    Yin, Zongjun; Zhu, Maoyan; Davidson, Eric H.; Bottjer, David J.; Zhao, Fangchen; Tafforeau, Paul

    2015-01-01

    An extraordinarily well preserved, 600-million-year (Myr)-old, three-dimensionally phosphatized fossil displaying multiple independent characters of modern adult sponges has been analyzed by SEM and synchrotron X-ray tomography. The fossilized animal (Eocyathispongia qiania gen. et sp. nov.) is slightly more than 1.2 mm wide and 1.1 mm tall, is composed of hundreds of thousands of cells, and has a gross structure consisting of three adjacent hollow tubes sharing a common base. The main tube is crowned with a large open funnel, and the others end in osculum-like openings to the exterior. The external surface is densely covered with flat tile-like cells closely resembling sponge pinacocytes, and this layer is punctuated with smaller pores. A dense patch of external structures that display the form of a lawn of sponge papillae has also survived. Within the main funnel, an area where features of the inner surface are preserved displays a regular pattern of uniform pits. Many of them are surrounded individually by distinct collars, mounted in a supporting reticulum. The possibility cannot be excluded that these pits are the remains of a field of choanocytes. The character set evinced by this specimen, ranging from general anatomy to cell type, uniquely indicates that this specimen is a fossil of probable poriferan affinity. So far, we have only this single specimen, and although its organized and complex cellular structure precludes any reasonable interpretation that its origin is abiogenic, confirmation that it is indeed a fossilized sponge will clearly require discovery of additional specimens. PMID:25775601

  6. Fabrication and analysis of microfiber array platform for optogenetics with cellular resolution

    PubMed Central

    Chen, Jian-Hong; Chou, Ming-Yi; Pan, Chien-Yuan; Wang, Lon A.

    2016-01-01

    Optogenetics has emerged as a revolutionary technology especially for neuroscience and has advanced continuously over the past decade. Conventional approaches for patterned in vivo optical illumination have a limitation on the implanted device size and achievable spatio-temporal resolution. In this work, we developed a fabrication process for a microfiber array platform. Arrayed poly(methyl methacrylate) (PMMA) microfibers were drawn from a polymer solution and packaged with polydimethylsiloxane (PDMS). The exposed end face of a packaged microfiber was tuned to have a size corresponding to a single cell. To demonstrate its capability for single cell optogenetics, HEK293T cells expressing channelrhodopsin-2 (ChR2) were cultured on the platform and excited with UV laser. We could then observe an elevation in the intracellular Ca2+ concentrations due to the influx of Ca2+ through the activated ChR2 into the cytosol. The statistical and simulation results indicate that the proposed microfiber array platform can be used for single cell optogenetic applications. PMID:27895984

  7. Volumetric optical coherence microscopy enabled by aberrated optics (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Mulligan, Jeffrey A.; Liu, Siyang; Adie, Steven G.

    2017-02-01

    Optical coherence microscopy (OCM) is an interferometric imaging technique that enables high resolution, non-invasive imaging of 3D cell cultures and biological tissues. Volumetric imaging with OCM suffers a trade-off between high transverse resolution and poor depth-of-field resulting from defocus, optical aberrations, and reduced signal collection away from the focal plane. While defocus and aberrations can be compensated with computational methods such as interferometric synthetic aperture microscopy (ISAM) or computational adaptive optics (CAO), reduced signal collection must be physically addressed through optical hardware. Axial scanning of the focus is one approach, but comes at the cost of longer acquisition times, larger datasets, and greater image reconstruction times. Given the capabilities of CAO to compensate for general phase aberrations, we present an alternative method to address the signal collection problem without axial scanning by using intentionally aberrated optical hardware. We demonstrate the use of an astigmatic spectral domain (SD-)OCM imaging system to enable single-acquisition volumetric OCM in 3D cell culture over an extended depth range, compared to a non-aberrated SD-OCM system. The transverse resolution of the non-aberrated and astigmatic imaging systems after application of CAO were 2 um and 2.2 um, respectively. The depth-range of effective signal collection about the nominal focal plane was increased from 100 um in the non-aberrated system to over 300 um in the astigmatic system, extending the range over which useful data may be acquired in a single OCM dataset. We anticipate that this method will enable high-throughput cellular-resolution imaging of dynamic biological systems over extended volumes.

  8. Sub-micrometer axial resolution OCT for in-vivo imaging of the cellular structure of healthy and keratoconic human corneas

    PubMed Central

    Bizheva, Kostadinka; Tan, Bingyao; MacLelan, Benjamin; Kralj, Olivera; Hajialamdari, Mojtaba; Hileeto, Denise; Sorbara, Luigina

    2017-01-01

    Corneal degenerative conditions such as keratoconus (KC) cause progressive damage to the anterior corneal tissue and eventually severely compromise visual acuity. The ability to visualize corneal tissue damage in-vivo at cellular or sub-cellular level at different stages of development of KC and other corneal diseases, can aid the early diagnostics as well as the development of more effective treatment approaches for various corneal pathologies, including keratoconus. Here, we present the optical design of an optical coherence tomography system that can achieve 0.95 µm axial resolution in biological tissue and provide test results for the system’s spatial resolution and sensitivity. Corneal images acquired in-vivo with this system from healthy and keratoconic human subjects reveal the cellular and sub-cellular structure of the corneal epithelium, as well as the normal and abnormal structure of the Bowman’s membrane and the anterior corneal stroma. PMID:28270986

  9. Volumetric structured illumination microscopy enabled by tunable focus lens (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Hinsdale, Taylor; Malik, Bilal; Olsovsky, Cory; Jo, Javier A.; Maitland, Kristen C.

    2016-03-01

    We present a volumetric imaging method for biological tissue that is free of mechanically scanning components. The optical sectioning in the system is obtained by structured illumination microscopy (SIM) with the depth of focus being varied by the use of an electronic tunable-focus lens (ETL). The performance of the axial scanning mechanism was evaluated and characterized in conjunction with SIM to ensure volumetric images could be recorded and reconstructed without significant losses in optical section thickness and lateral resolution over the full desired scan range. It was demonstrated that sub-cellular image resolutions were obtainable in both microsphere films and in ex vivo oral mucosa, spanning multiple cell layers, without significant losses in image quality. The mechanism proposed here has the ability to be integrated into any wide-field microscopy system to convert it into a three-dimensional imaging platform without the need for axial scanning of the sample or imaging optics. The ability to axially scan independent of mechanical movement also provides the opportunity for the development of endoscopic systems which can create volumetric images of tissue in vivo.

  10. Mapping whole-brain activity with cellular resolution by light-sheet microscopy and high-throughput image analysis (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Silvestri, Ludovico; Rudinskiy, Nikita; Paciscopi, Marco; Müllenbroich, Marie Caroline; Costantini, Irene; Sacconi, Leonardo; Frasconi, Paolo; Hyman, Bradley T.; Pavone, Francesco S.

    2016-03-01

    Mapping neuronal activity patterns across the whole brain with cellular resolution is a challenging task for state-of-the-art imaging methods. Indeed, despite a number of technological efforts, quantitative cellular-resolution activation maps of the whole brain have not yet been obtained. Many techniques are limited by coarse resolution or by a narrow field of view. High-throughput imaging methods, such as light sheet microscopy, can be used to image large specimens with high resolution and in reasonable times. However, the bottleneck is then moved from image acquisition to image analysis, since many TeraBytes of data have to be processed to extract meaningful information. Here, we present a full experimental pipeline to quantify neuronal activity in the entire mouse brain with cellular resolution, based on a combination of genetics, optics and computer science. We used a transgenic mouse strain (Arc-dVenus mouse) in which neurons which have been active in the last hours before brain fixation are fluorescently labelled. Samples were cleared with CLARITY and imaged with a custom-made confocal light sheet microscope. To perform an automatic localization of fluorescent cells on the large images produced, we used a novel computational approach called semantic deconvolution. The combined approach presented here allows quantifying the amount of Arc-expressing neurons throughout the whole mouse brain. When applied to cohorts of mice subject to different stimuli and/or environmental conditions, this method helps finding correlations in activity between different neuronal populations, opening the possibility to infer a sort of brain-wide 'functional connectivity' with cellular resolution.

  11. An effective assay for high cellular resolution time-lapse imaging of sensory placode formation and morphogenesis

    PubMed Central

    2011-01-01

    Background The vertebrate peripheral nervous system contains sensory neurons that arise from ectodermal placodes. Placodal cells ingress to move inside the head to form sensory neurons of the cranial ganglia. To date, however, the process of placodal cell ingression and underlying cellular behavior are poorly understood as studies have relied upon static analyses on fixed tissues. Visualizing placodal cell behavior requires an ability to distinguish the surface ectoderm from the underlying mesenchyme. This necessitates high resolution imaging along the z-plane which is difficult to accomplish in whole embryos. To address this issue, we have developed an imaging system using cranial slices that allows direct visualization of placode formation. Results We demonstrate an effective imaging assay for capturing placode development at single cell resolution using chick embryonic tissue ex vivo. This provides the first time-lapse imaging of mitoses in the trigeminal placodal ectoderm, ingression, and intercellular contacts of placodal cells. Cell divisions with varied orientations were found in the placodal ectoderm all along the apical-basal axis. Placodal cells initially have short cytoplasmic processes during ingression as young neurons and mature over time to elaborate long axonal processes in the mesenchyme. Interestingly, the time-lapse imaging data reveal that these delaminating placodal neurons begin ingression early on from within the ectoderm, where they start to move and continue on to exit as individual or strings of neurons through common openings on the basal side of the epithelium. Furthermore, dynamic intercellular contacts are abundant among the delaminating placodal neurons, between these and the already delaminated cells, as well as among cells in the forming ganglion. Conclusions This new imaging assay provides a powerful method to analyze directly development of placode-derived sensory neurons and subsequent ganglia formation for the first time in

  12. Flexible Volumetric Structure

    NASA Technical Reports Server (NTRS)

    Cagle, Christopher M. (Inventor); Schlecht, Robin W. (Inventor)

    2014-01-01

    A flexible volumetric structure has a first spring that defines a three-dimensional volume and includes a serpentine structure elongatable and compressible along a length thereof. A second spring is coupled to at least one outboard edge region of the first spring. The second spring is a sheet-like structure capable of elongation along an in-plane dimension thereof. The second spring is oriented such that its in-plane dimension is aligned with the length of the first spring's serpentine structure.

  13. JPEG2000 Part 10: volumetric imaging

    NASA Astrophysics Data System (ADS)

    Schelkens, Peter; Brislawn, Christopher M.; Barbarien, Joeri; Munteanu, Adrian; Cornelis, Jan P.

    2003-11-01

    Recently, the JPEG2000 committee (ISO/IEC JTC1/SC29/WG1) decided to start up a new standardization activity to support the encoding of volumetric and floating-point data sets: Part 10 - Coding Volumetric and Floating-point Data (JP3D). This future standard will support functionalities like resolution and quality scalability and region-of-interest coding, while exploiting the entropy in the additional third dimension to improve the rate-distortion performance. In this paper, we give an overview of the markets and application areas targeted by JP3D, the imposed requirements and the considered algorithms with a specific focus on the realization of the region-of-interest functionality.

  14. Ultrahigh resolution photoacoustic microscopy via transient absorption

    PubMed Central

    Shelton, Ryan L.; Applegate, Brian E.

    2010-01-01

    We have developed a novel, hybrid imaging modality, Transient Absorption Ultrasonic Microscopy (TAUM), which takes advantage of the optical nonlinearities afforded by transient absorption to achieve ultrahigh-resolution photoacoustic microscopy. The theoretical point spread function for TAUM is functionally equivalent to confocal and two-photon fluorescence microscopy, potentially enabling cellular/subcellular photoacoustic imaging. A prototype TAUM system was designed, built, and used to image a cross-section through several capillaries in the excised cheek pouch of a Syrian Hamster. The well-resolved capillaries in the TAUM image provided experimental evidence of the spatial resolution. These results suggest that TAUM has excellent potential for producing volumetric images with cellular/subcellular resolution in three dimensions deep inside living tissue. PMID:21258499

  15. VOLUMETRIC TANK TESTING: AN OVERVIEW

    EPA Science Inventory

    This report summarizes the technical findings of an EPA study on volumetric tank testing. It describes the results of the EPA study, which evaluated the viability of volumetric tank tests as a means of detecting leaks in underground storage tanks. It explains the accuracy requi...

  16. VOLUMETRIC TANK TESTING: AN OVERVIEW

    EPA Science Inventory

    This report summarizes the technical findings of an EPA study on volumetric tank testing. The results of this study, which evaluated the viability of volumetric tank tests as a means of detecting leaks in underground storage tanks, are described. Also, the accuracy requirements s...

  17. Dinuclear osmium(II) probes for high-resolution visualisation of cellular DNA structure using electron microscopy.

    PubMed

    Wragg, Ashley; Gill, Martin R; Hill, Christopher J; Su, Xiaodi; Meijer, Anthony J H M; Smythe, Carl; Thomas, Jim A

    2014-12-04

    Two dinuclear osmium polypyridyl complexes function as convenient, easy to handle TEM contrast agents and facilitate the high-resolution visualisation of intracellular structure, particularly sub-nuclear detail.

  18. Site–Specific Sonoporation of Human Melanoma Cells at the Cellular Level Using High Lateral–Resolution Ultrasonic Micro–Transducer Arrays

    PubMed Central

    Thein, Myo; Cheng, An; Khanna, Payal; Zhang, Chunfeng; Park, Eun–Joo; Ahmed, Daniel; Goodrich, Christopher J.; Asphahani, Fareid; Wu, Fengbing; Smith, Nadine B.; Dong, Cheng; Jiang, Xiaoning; Zhang, Miqin; Xu, Jian

    2011-01-01

    We developed a new instrumental method by which human melanoma cells (LU1205) are sonoporated via radiation pressures exerted by highly–confined ultrasonic waves produced by high lateral–resolution Ultrasonic Micro–Transducer Arrays (UMTAs). The method enables cellular–level site–specific sonoporation within the cell monolayer due to UMTAs and can be applicable in the delivery of drugs and gene products in cellular assays. In this method, cells are seeded on the biochip that employs UMTAs for high spatial resolution and specificity. UMTAs are driven by 30–MHz sinusoidal signals and the resulting radiation pressures induce sonoporation in the targeted cells. The sonoporation degree and the effective lateral resolution of UMTAs are determined by performing fluorescent microscopy and analysis of carboxylic–acid–derivatized CdSe/ZnS quantum dots passively transported into the cells. Models representing the transducer–generated ultrasound radiation pressure, the ultrasound–inflicted cell membrane wound, and the transmembrane transport through the wound are developed to determine the ultrasound–pressure–dependent wound size and enhanced cellular uptake of nanoparticles. Model–based calculations show that the effective wound size and cellular uptake of nanoparticles increase linearly with increasing ultrasound pressure (i.e., at applied radiation pressures of 0.21, 0.29, and 0.40 MPa, the ultrasound–induced initial effective wound radii are 150, 460, and 650 nm, respectively, and the post–sonoporation intracellular quantum–dot concentrations are 7.8, 22.8, and 29.9 nM, respectively) and the threshold pressure required to induce sonoporation in LU1205 cells is ~0.12 MPa. PMID:21783355

  19. A volumetric data system for environmental robotics

    SciTech Connect

    Tourtellott, J.

    1994-12-31

    A three-dimensional, spatially organized or volumetric data system provides an effective means for integrating and presenting environmental sensor data to robotic systems and operators. Because of the unstructed nature of environmental restoration applications, new robotic control strategies are being developed that include environmental sensors and interactive data interpretation. The volumetric data system provides key features to facilitate these new control strategies including: integrated representation of surface, subsurface and above-surface data; differentiation of mapped and unmapped regions in space; sculpting of regions in space to best exploit data from line-of-sight sensors; integration of diverse sensor data (for example, dimensional, physical/geophysical, chemical, and radiological); incorporation of data provided at different spatial resolutions; efficient access for high-speed visualization and analysis; and geometric modeling tools to update a {open_quotes}world model{close_quotes} of an environment. The applicability to underground storage tank remediation and buried waste site remediation are demonstrated in several examples. By integrating environmental sensor data into robotic control, the volumetric data system will lead to safer, faster, and more cost-effective environmental cleanup.

  20. GPU-based computational adaptive optics for volumetric optical coherence microscopy

    NASA Astrophysics Data System (ADS)

    Tang, Han; Mulligan, Jeffrey A.; Untracht, Gavrielle R.; Zhang, Xihao; Adie, Steven G.

    2016-03-01

    Optical coherence tomography (OCT) is a non-invasive imaging technique that measures reflectance from within biological tissues. Current higher-NA optical coherence microscopy (OCM) technologies with near cellular resolution have limitations on volumetric imaging capabilities due to the trade-offs between resolution vs. depth-of-field and sensitivity to aberrations. Such trade-offs can be addressed using computational adaptive optics (CAO), which corrects aberration computationally for all depths based on the complex optical field measured by OCT. However, due to the large size of datasets plus the computational complexity of CAO and OCT algorithms, it is a challenge to achieve high-resolution 3D-OCM reconstructions at speeds suitable for clinical and research OCM imaging. In recent years, real-time OCT reconstruction incorporating both dispersion and defocus correction has been achieved through parallel computing on graphics processing units (GPUs). We add to these methods by implementing depth-dependent aberration correction for volumetric OCM using plane-by-plane phase deconvolution. Following both defocus and aberration correction, our reconstruction algorithm achieved depth-independent transverse resolution of 2.8 um, equal to the diffraction-limited focal plane resolution. We have translated the CAO algorithm to a CUDA code implementation and tested the speed of the software in real-time using two GPUs - NVIDIA Quadro K600 and Geforce TITAN Z. For a data volume containing 4096×256×256 voxels, our system's processing speed can keep up with the 60 kHz acquisition rate of the line-scan camera, and takes 1.09 seconds to simultaneously update the CAO correction for 3 en face planes at user-selectable depths.

  1. Fluorescent scanning laser ophthalmoscopy for cellular resolution in vivo mouse retinal imaging: benefits and drawbacks of implementing adaptive optics (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Zhang, Pengfei; Goswami, Mayank; Pugh, Edward N.; Zawadzki, Robert J.

    2016-03-01

    Scanning Laser Ophthalmoscopy (SLO) is a very important imaging tool in ophthalmology research. By combing with Adaptive Optics (AO) technique, AO-SLO can correct for ocular aberrations resulting in cellular level resolution, allowing longitudinal studies of single cells morphology in the living eyes. The numerical aperture (NA) sets the optical resolution that can be achieve in the "classical" imaging systems. Mouse eye has more than twice NA of the human eye, thus offering theoretically higher resolution. However, in most SLO based imaging systems the imaging beam size at mouse pupil sets the NA of that instrument, while most of the AO-SLO systems use almost the full NA of the mouse eye. In this report, we first simulated the theoretical resolution that can be achieved in vivo for different imaging beam sizes (different NA), assumingtwo cases: no aberrations and aberrations based on published mouse ocular wavefront data. Then we imaged mouse retinas with our custom build SLO system using different beam sizes to compare these results with theory. Further experiments include comparison of the SLO and AO-SLO systems for imaging different type of fluorescently labeled cells (microglia, ganglion, photoreceptors, etc.). By comparing those results and taking into account systems complexity and ease of use, the benefits and drawbacks of two imaging systems will be discussed.

  2. Volumetric stress-strain analysis of optohydrodynamically suspended biological cells.

    PubMed

    Kohles, Sean S; Liang, Yu; Saha, Asit K

    2011-01-01

    Ongoing investigations are exploring the biomechanical properties of isolated and suspended biological cells in pursuit of understanding single-cell mechanobiology. An optical tweezer with minimal applied laser power has positioned biologic cells at the geometric center of a microfluidic cross-junction, creating a novel optohydrodynamic trap. The resulting fluid flow environment facilitates unique multiaxial loading of single cells with site-specific normal and shear stresses resulting in a physical albeit extensional state. A recent two-dimensional analysis has explored the cytoskeletal strain response due to these fluid-induced stresses [Wilson and Kohles, 2010, "Two-Dimensional Modeling of Nanomechanical Stresses-Strains in Healthy and Diseased Single-Cells During Microfluidic Manipulation," J Nanotechnol Eng Med, 1(2), p. 021005]. Results described a microfluidic environment having controlled nanometer and piconewton resolution. In this present study, computational fluid dynamics combined with multiphysics modeling has further characterized the applied fluid stress environment and the solid cellular strain response in three dimensions to accompany experimental cell stimulation. A volumetric stress-strain analysis was applied to representative living cell biomechanical data. The presented normal and shear stress surface maps will guide future microfluidic experiments as well as provide a framework for characterizing cytoskeletal structure influencing the stress to strain response.

  3. Volumetric Stress-Strain Analysis of Optohydrodynamically Suspended Biological Cells

    PubMed Central

    Liang, Yu; Saha, Asit K.

    2011-01-01

    Ongoing investigations are exploring the biomechanical properties of isolated and suspended biological cells in pursuit of understanding single-cell mechanobiology. An optical tweezer with minimal applied laser power has positioned biologic cells at the geometric center of a microfluidic cross-junction, creating a novel optohydrodynamic trap. The resulting fluid flow environment facilitates unique multiaxial loading of single cells with site-specific normal and shear stresses resulting in a physical albeit extensional state. A recent two-dimensional analysis has explored the cytoskeletal strain response due to these fluid-induced stresses [Wilson and Kohles, 2010, “Two-Dimensional Modeling of Nanomechanical Stresses-Strains in Healthy and Diseased Single-Cells During Microfluidic Manipulation,” J Nanotechnol Eng Med, 1(2), p. 021005]. Results described a microfluidic environment having controlled nanometer and piconewton resolution. In this present study, computational fluid dynamics combined with multiphysics modeling has further characterized the applied fluid stress environment and the solid cellular strain response in three dimensions to accompany experimental cell stimulation. A volumetric stress-strain analysis was applied to representative living cell biomechanical data. The presented normal and shear stress surface maps will guide future microfluidic experiments as well as provide a framework for characterizing cytoskeletal structure influencing the stress to strain response. PMID:21186894

  4. Cellular structure of the healthy and keratoconic human cornea imaged in-vivo with sub-micrometer axial resolution OCT(Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Bizheva, Kostadinka; Tan, Bingyao; Mason, Erik; Carter, Kirsten; Haines, Lacey; Sorbara, Luigina

    2017-02-01

    Keratoconus causes progressive morphological changes in the corneal epithelium (EPI), Bowman's membrane (BM) and anterior stroma. However, it is still not well understood if KC originates in the corneal epithelium and propagates to the anterior stroma through disruptions of the BM, or vice versa. In this study we used a sub-micrometer axial resolution OCT system to image in-vivo the cellular structure of the EPI layer and the fibrous structure of the BM and the anterior stroma in mild to advanced keratoconics, as well as healthy subjects. The imaging study was approved by the University of Waterloo Human Research Ethics Committee. The OCT system operates in the 800 nm spectral region at 34 kHz image acquisition rate and provides 0.95 um axial and < 2 um lateral resolution in corneal tissue, which is sufficient to visualize the cellular structure of the corneal epithelium and the fibrous structure of the BM. In some subjects, localized thinning and thickening of the EPI layer was observed, while there was no visible damage to the BM or anterior stroma. In other subjects, localized breakage of the stromal collagen fibrils was observed with no significant morphological changes of the corneal EPI.

  5. Integral volumetric imaging using decentered elemental lenses.

    PubMed

    Sawada, Shimpei; Kakeya, Hideki

    2012-11-05

    This paper proposes a high resolution integral imaging system using a lens array composed of non-uniform decentered elemental lenses. One of the problems of integral imaging is the trade-off relationship between the resolution and the number of views. When the number of views is small, motion parallax becomes strongly discrete to maintain the viewing angle. In order to overcome this trade-off, the proposed method uses the elemental lenses whose size is smaller than that of the elemental images. To keep the images generated by the elemental lenses at constant depth, the lens array is designed so that the optical centers of elemental lenses may be located in the centers of elemental images, not in the centers of elemental lenses. To compensate optical distortion, new image rendering algorithm is developed so that undistorted 3D image may be presented with a non-uniform lens array. The proposed design of lens array can be applied to integral volumetric imaging, where display panels are layered to show volumetric images in the scheme of integral imaging.

  6. A digital framework to build, visualize and analyze a gene expression atlas with cellular resolution in zebrafish early embryogenesis.

    PubMed

    Castro-González, Carlos; Luengo-Oroz, Miguel A; Duloquin, Louise; Savy, Thierry; Rizzi, Barbara; Desnoulez, Sophie; Doursat, René; Kergosien, Yannick L; Ledesma-Carbayo, María J; Bourgine, Paul; Peyriéras, Nadine; Santos, Andrés

    2014-06-01

    A gene expression atlas is an essential resource to quantify and understand the multiscale processes of embryogenesis in time and space. The automated reconstruction of a prototypic 4D atlas for vertebrate early embryos, using multicolor fluorescence in situ hybridization with nuclear counterstain, requires dedicated computational strategies. To this goal, we designed an original methodological framework implemented in a software tool called Match-IT. With only minimal human supervision, our system is able to gather gene expression patterns observed in different analyzed embryos with phenotypic variability and map them onto a series of common 3D templates over time, creating a 4D atlas. This framework was used to construct an atlas composed of 6 gene expression templates from a cohort of zebrafish early embryos spanning 6 developmental stages from 4 to 6.3 hpf (hours post fertilization). They included 53 specimens, 181,415 detected cell nuclei and the segmentation of 98 gene expression patterns observed in 3D for 9 different genes. In addition, an interactive visualization software, Atlas-IT, was developed to inspect, supervise and analyze the atlas. Match-IT and Atlas-IT, including user manuals, representative datasets and video tutorials, are publicly and freely available online. We also propose computational methods and tools for the quantitative assessment of the gene expression templates at the cellular scale, with the identification, visualization and analysis of coexpression patterns, synexpression groups and their dynamics through developmental stages.

  7. A Digital Framework to Build, Visualize and Analyze a Gene Expression Atlas with Cellular Resolution in Zebrafish Early Embryogenesis

    PubMed Central

    Castro-González, Carlos; Luengo-Oroz, Miguel A.; Duloquin, Louise; Savy, Thierry; Rizzi, Barbara; Desnoulez, Sophie; Doursat, René; Kergosien, Yannick L.; Ledesma-Carbayo, María J.; Bourgine, Paul

    2014-01-01

    A gene expression atlas is an essential resource to quantify and understand the multiscale processes of embryogenesis in time and space. The automated reconstruction of a prototypic 4D atlas for vertebrate early embryos, using multicolor fluorescence in situ hybridization with nuclear counterstain, requires dedicated computational strategies. To this goal, we designed an original methodological framework implemented in a software tool called Match-IT. With only minimal human supervision, our system is able to gather gene expression patterns observed in different analyzed embryos with phenotypic variability and map them onto a series of common 3D templates over time, creating a 4D atlas. This framework was used to construct an atlas composed of 6 gene expression templates from a cohort of zebrafish early embryos spanning 6 developmental stages from 4 to 6.3 hpf (hours post fertilization). They included 53 specimens, 181,415 detected cell nuclei and the segmentation of 98 gene expression patterns observed in 3D for 9 different genes. In addition, an interactive visualization software, Atlas-IT, was developed to inspect, supervise and analyze the atlas. Match-IT and Atlas-IT, including user manuals, representative datasets and video tutorials, are publicly and freely available online. We also propose computational methods and tools for the quantitative assessment of the gene expression templates at the cellular scale, with the identification, visualization and analysis of coexpression patterns, synexpression groups and their dynamics through developmental stages. PMID:24945246

  8. Quantitative Techniques in Volumetric Analysis

    NASA Astrophysics Data System (ADS)

    Zimmerman, John; Jacobsen, Jerrold J.

    1996-12-01

    Quantitative Techniques in Volumetric Analysis is a visual library of techniques used in making volumetric measurements. This 40-minute VHS videotape is designed as a resource for introducing students to proper volumetric methods and procedures. The entire tape, or relevant segments of the tape, can also be used to review procedures used in subsequent experiments that rely on the traditional art of quantitative analysis laboratory practice. The techniques included are: Quantitative transfer of a solid with a weighing spoon Quantitative transfer of a solid with a finger held weighing bottle Quantitative transfer of a solid with a paper strap held bottle Quantitative transfer of a solid with a spatula Examples of common quantitative weighing errors Quantitative transfer of a solid from dish to beaker to volumetric flask Quantitative transfer of a solid from dish to volumetric flask Volumetric transfer pipet A complete acid-base titration Hand technique variations The conventional view of contemporary quantitative chemical measurement tends to focus on instrumental systems, computers, and robotics. In this view, the analyst is relegated to placing standards and samples on a tray. A robotic arm delivers a sample to the analysis center, while a computer controls the analysis conditions and records the results. In spite of this, it is rare to find an analysis process that does not rely on some aspect of more traditional quantitative analysis techniques, such as careful dilution to the mark of a volumetric flask. Figure 2. Transfer of a solid with a spatula. Clearly, errors in a classical step will affect the quality of the final analysis. Because of this, it is still important for students to master the key elements of the traditional art of quantitative chemical analysis laboratory practice. Some aspects of chemical analysis, like careful rinsing to insure quantitative transfer, are often an automated part of an instrumental process that must be understood by the

  9. Three-Dimensional Analysis of Syncytial-Type Cell Plates during Endosperm Cellularization Visualized by High Resolution Electron Tomography W⃞

    PubMed Central

    Otegui, Marisa S.; Mastronarde, David N.; Kang, Byung-Ho; Bednarek, Sebastian Y.; Staehelin, L. Andrew

    2001-01-01

    The three-dimensional architecture of syncytial-type cell plates in the endosperm of Arabidopsis has been analyzed at ∼6-nm resolution by means of dual-axis high-voltage electron tomography of high-pressure frozen/freeze-substituted samples. Mini-phragmoplasts consisting of microtubule clusters assemble between sister and nonsister nuclei. Most Golgi-derived vesicles appear connected to these microtubules by two molecules that resemble kinesin-like motor proteins. These vesicles fuse with each other to form hourglass-shaped intermediates, which become wide (∼45 nm in diameter) tubules, the building blocks of wide tubular networks. New mini-phragmoplasts also are generated de novo around the margins of expanding wide tubular networks, giving rise to new foci of cell plate growth, which later become integrated into the main cell plate. Spiral-shaped rings of the dynamin-like protein ADL1A constrict but do not fission the wide tubules at irregular intervals. These rings appear to maintain the tubular geometry of the network. The wide tubular network matures into a convoluted fenestrated sheet in a process that involves increases of 45 and 130% in relative membrane surface area and volume, respectively. The proportionally larger increase in volume appears to reflect callose synthesis. Upon fusion with the parental plasma membrane, the convoluted fenestrated sheet is transformed into a planar fenestrated sheet. This transformation involves clathrin-coated vesicles that reduce the relative membrane surface area and volume by ∼70%. A ribosome-excluding matrix encompasses the cell plate membranes from the fusion of the first vesicles until the onset of the planar fenestrated sheet formation. We postulate that this matrix contains the molecules that mediate cell plate assembly. PMID:11549762

  10. Cellular basis for trigger and maintenance of ventricular fibrillation in the Brugada syndrome model: high-resolution optical mapping study.

    PubMed

    Aiba, Takeshi; Shimizu, Wataru; Hidaka, Ichiro; Uemura, Kazunori; Noda, Takashi; Zheng, Can; Kamiya, Atsunori; Inagaki, Masashi; Sugimachi, Masaru; Sunagawa, Kenji

    2006-05-16

    We examined how repolarization and depolarization abnormalities contribute to the development of extrasystoles and subsequent ventricular fibrillation (VF) in a model of the Brugada syndrome. Repolarization and depolarization abnormalities have been considered to be mechanisms of the coved-type ST-segment elevation (Brugada-electrocardiogram [ECG]) and development of VF in the Brugada syndrome. We used high-resolution (256 x 256) optical mapping techniques to study arterially perfused canine right ventricular wedges (n = 20) in baseline and in the Brugada-ECG produced by administration of terfenadine (5 micromol/l), pinacidil (2 micromol/l), and pilsicainide (5 micromol/l). We recorded spontaneous episodes of phase 2 re-entrant (P2R)-extrasystoles and subsequent self-terminating polymorphic ventricular tachycardia (PVT) or VF under the Brugada-ECG condition and analyzed the epicardial conduction velocity and action potential duration (APD) restitutions in each condition. Forty-one episodes of spontaneous P2R-extrasystoles in the Brugada-ECG were successfully mapped in 9 of 10 preparations, and 33 of them were originated from the maximum gradient of repolarization (GR(max): 176 +/- 54 ms/mm) area in the epicardium, leading to PVT (n = 12) or VF (n = 5). The epicardial GR(max) was not different between PVT and VF. Wave-break during the first P2R-extrasystole produced multiple wavelets in all VF cases, whereas no wave-break or wave-break followed by wave collision and termination occurred in PVT cases. Moreover, conduction velocity restitution was shifted lower and APD restitution was more variable in VF cases than in PVT cases. Steep repolarization gradient in the epicardium but not endocardium develops P2R-extrasystoles in the Brugada-ECG condition, which might degenerate into VF by further depolarization and repolarization abnormalities.

  11. Volumetric Light-Field Excitation

    PubMed Central

    Schedl, David C.; Bimber, Oliver

    2016-01-01

    We explain how to concentrate light simultaneously at multiple selected volumetric positions by means of a 4D illumination light field. First, to select target objects, a 4D imaging light field is captured. A light field mask is then computed automatically for this selection to avoid illumination of the remaining areas. With one-photon illumination, simultaneous generation of complex volumetric light patterns becomes possible. As a full light-field can be captured and projected simultaneously at the desired exposure and excitation times, short readout and lighting durations are supported. PMID:27363565

  12. Rapid mapping of volumetric errors

    SciTech Connect

    Krulewich, D.; Hale, L.; Yordy, D.

    1995-09-13

    This paper describes a relatively inexpensive, fast, and easy to execute approach to mapping the volumetric errors of a machine tool, coordinate measuring machine, or robot. An error map is used to characterize a machine or to improve its accuracy by compensating for the systematic errors. The method consists of three steps: (1) modeling the relationship between the volumetric error and the current state of the machine; (2) acquiring error data based on length measurements throughout the work volume; and (3) optimizing the model to the particular machine.

  13. All Photons Imaging Through Volumetric Scattering

    PubMed Central

    Satat, Guy; Heshmat, Barmak; Raviv, Dan; Raskar, Ramesh

    2016-01-01

    Imaging through thick highly scattering media (sample thickness ≫ mean free path) can realize broad applications in biomedical and industrial imaging as well as remote sensing. Here we propose a computational “All Photons Imaging” (API) framework that utilizes time-resolved measurement for imaging through thick volumetric scattering by using both early arrived (non-scattered) and diffused photons. As opposed to other methods which aim to lock on specific photons (coherent, ballistic, acoustically modulated, etc.), this framework aims to use all of the optical signal. Compared to conventional early photon measurements for imaging through a 15 mm tissue phantom, our method shows a two fold improvement in spatial resolution (4db increase in Peak SNR). This all optical, calibration-free framework enables widefield imaging through thick turbid media, and opens new avenues in non-invasive testing, analysis, and diagnosis. PMID:27683065

  14. Volumetric Geophysical Retrievals in Precipitating Cloud Systems

    NASA Astrophysics Data System (ADS)

    Collis, S. M.; North, K. W.; Jensen, M. P.; Kollias, P.; Williams, C. R.; Bharadwaj, N.; Fridlind, A. M.; Widener, K.; Giangrande, S.

    2011-12-01

    Cloud and climate modeling efforts focused around the Mid-Latitude Continental Convective Clouds Experiment (MC3E) require the retrieval of high quality geophysical parameters pertinent to storm microphysical and dynamical properties. The installation of high resolution polarimetric X- and C-Band scanning radars have greatly enhanced measurements at the Atmospheric Radiation Measurement Southern Great Plain site, however, the volumetric data collected by these sensors is only indirectly related to storm properties. This presentation will outline efforts towards creating a suite of model-like Value Added Products (VAPs) for MC3E derived using existing and new retrieval techniques. Particular focus will be on retrieval of storm dynamics, precipitation microphysics and rainfall accumulations from the scanning radar measurements. Algorithm details and verification efforts will be showcased as well as a timetable for data availability.

  15. All Photons Imaging Through Volumetric Scattering

    NASA Astrophysics Data System (ADS)

    Satat, Guy; Heshmat, Barmak; Raviv, Dan; Raskar, Ramesh

    2016-09-01

    Imaging through thick highly scattering media (sample thickness ≫ mean free path) can realize broad applications in biomedical and industrial imaging as well as remote sensing. Here we propose a computational “All Photons Imaging” (API) framework that utilizes time-resolved measurement for imaging through thick volumetric scattering by using both early arrived (non-scattered) and diffused photons. As opposed to other methods which aim to lock on specific photons (coherent, ballistic, acoustically modulated, etc.), this framework aims to use all of the optical signal. Compared to conventional early photon measurements for imaging through a 15 mm tissue phantom, our method shows a two fold improvement in spatial resolution (4db increase in Peak SNR). This all optical, calibration-free framework enables widefield imaging through thick turbid media, and opens new avenues in non-invasive testing, analysis, and diagnosis.

  16. Multiple site optical recording of transmembrane voltage (MSORTV) in patterned growth heart cell cultures: assessing electrical behavior, with microsecond resolution, on a cellular and subcellular scale.

    PubMed Central

    Rohr, S; Salzberg, B M

    1994-01-01

    We have applied multiple site optical recording of transmembrane voltage (MSORTV) to patterned growth cultures of heart cells to analyze the effect of geometry per se on impulse propagation in excitable tissue, with cellular and subcellular resolution. Extensive dye screening led to the choice of di-8-ANEPPS as the most suitable voltage-sensitive dye for this application; it is internalized slowly and permits optical recording with signal-to-noise ratios as high as 40:1 (measured peak-to-peak) and average fractional fluorescence changes of 15% per 100 mV. Using a x 100 objective and a fast data acquisition system, we could resolve impulse propagation on a microscopic scale (15 microns) with high temporal resolution (uncertainty of +/- 5 microseconds). We could observe the decrease in conduction velocity of an impulse propagating along a narrow cell strand as it enters a region of abrupt expansion, and we could explain this phenomenon in terms of the micro-architecture of the tissue. In contrast with the elongated and aligned cells forming the narrow strands, the cells forming the expansions were aligned at random and presented 2.5 times as many cell-to-cell appositions per unit length. If the decrease in conduction velocity results entirely from this increased number of cell-to-cell boundaries per unit length, the mean activation delay introduced by each boundary can be estimated to be 70 microseconds. Using this novel experimental system, we could also demonstrate the electrical coupling of fibroblasts and endotheloid cells to myocytes in culture. Images FIGURE 1 FIGURE 2 FIGURE 4 FIGURE 5 FIGURE 7 FIGURE 8 PMID:7811945

  17. Volumetric chemical imaging by stimulated Raman projection microscopy and tomography

    PubMed Central

    Chen, Xueli; Zhang, Chi; Lin, Peng; Huang, Kai-Chih; Liang, Jimin; Tian, Jie; Cheng, Ji-Xin

    2017-01-01

    Volumetric imaging allows global understanding of three-dimensional (3D) complex systems. Light-sheet fluorescence microscopy and optical projection tomography have been reported to image 3D volumes with high resolutions and at high speeds. Such methods, however, usually rely on fluorescent labels for chemical targeting, which could perturb the biological functionality in living systems. We demonstrate Bessel-beam-based stimulated Raman projection (SRP) microscopy and tomography for label-free volumetric chemical imaging. Our SRP microscope enables fast quantitation of chemicals in a 3D volume through a two-dimensional lateral scan. Furthermore, combining SRP and sample rotation, we demonstrate the SRP tomography that can reconstruct the 3D distribution of chemical compositions with optical spatial resolution at a higher speed than the Gaussian-beam-based stimulated Raman scattering sectioning imaging can. We explore the potential of our SRP technology by mapping polymer particles in 3D volumes and lipid droplets in adipose cells. PMID:28436473

  18. Volumetric chemical imaging by stimulated Raman projection microscopy and tomography

    NASA Astrophysics Data System (ADS)

    Chen, Xueli; Zhang, Chi; Lin, Peng; Huang, Kai-Chih; Liang, Jimin; Tian, Jie; Cheng, Ji-Xin

    2017-04-01

    Volumetric imaging allows global understanding of three-dimensional (3D) complex systems. Light-sheet fluorescence microscopy and optical projection tomography have been reported to image 3D volumes with high resolutions and at high speeds. Such methods, however, usually rely on fluorescent labels for chemical targeting, which could perturb the biological functionality in living systems. We demonstrate Bessel-beam-based stimulated Raman projection (SRP) microscopy and tomography for label-free volumetric chemical imaging. Our SRP microscope enables fast quantitation of chemicals in a 3D volume through a two-dimensional lateral scan. Furthermore, combining SRP and sample rotation, we demonstrate the SRP tomography that can reconstruct the 3D distribution of chemical compositions with optical spatial resolution at a higher speed than the Gaussian-beam-based stimulated Raman scattering sectioning imaging can. We explore the potential of our SRP technology by mapping polymer particles in 3D volumes and lipid droplets in adipose cells.

  19. Direct identification of human cellular microRNAs by nanoflow liquid chromatography-high-resolution tandem mass spectrometry and database searching.

    PubMed

    Nakayama, Hiroshi; Yamauchi, Yoshio; Taoka, Masato; Isobe, Toshiaki

    2015-03-03

    MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene networks and participate in many physiological and pathological pathways. To date, miRNAs have been characterized mostly by genetic technologies, which have the advantages of being very sensitive and using high-throughput instrumentation; however, these techniques cannot identify most post-transcriptional modifications of miRNAs that would affect their functions. Herein, we report an analytical system for the direct identification of miRNAs that incorporates nanoflow liquid chromatography-high-resolution tandem mass spectrometry and RNA-sequence database searching. By introducing a spray-assisting device that stabilizes negative nanoelectrospray ionization of RNAs and by searching an miRNA sequence database using the obtained tandem mass spectrometry data for the RNA mixture, we successfully identified femtomole quantities of human cellular miRNAs and their 3'-terminal variants. This is the first report of a fully automated, and thus objective, tandem mass spectrometry-based analytical system that can be used to identify miRNAs.

  20. Hierarchical band-target entropy minimization curve resolution and Pearson VII curve-fitting analysis of cellular protein infrared imaging spectra.

    PubMed

    Xu, Weiyin; Chen, Kejia; Liang, Dayang; Chew, Wee

    2009-04-01

    A soft-modeling multivariate numerical approach that combines self-modeling curve resolution (SMCR) and mixed Lorentzian-Gaussian curve fitting was successfully implemented for the first time to elucidate spatially and spectroscopically resolved spectral information from infrared imaging data of oral mucosa cells. A novel variant form of the robust band-target entropy minimization (BTEM) SMCR technique, coined as hierarchical BTEM (hBTEM), was introduced to first cluster similar cellular infrared spectra using the unsupervised hierarchical leader-follower cluster analysis (LFCA) and subsequently apply BTEM to clustered subsets of data to reconstruct three protein secondary structure (PSS) pure component spectra-alpha-helix, beta-sheet, and ambiguous structures-that associate with spatially differentiated regions of the cell infrared image. The Pearson VII curve-fitting procedure, which approximates a mixed Lorentzian-Gaussian model for spectral band shape, was used to optimally curve fit the resolved amide I and II bands of various hBTEM reconstructed PSS pure component spectra. The optimized Pearson VII band-shape parameters and peak center positions serve as means to characterize amide bands of PSS spectra found in various cell locations and for approximating their actual amide I/II intensity ratios. The new hBTEM methodology can also be potentially applied to vibrational spectroscopic datasets with dynamic or spatial variations arising from chemical reactions, physical perturbations, pathological states, and the like.

  1. Volumetric imaging of fish locomotion

    PubMed Central

    Flammang, Brooke E.; Lauder, George V.; Troolin, Daniel R.; Strand, Tyson E.

    2011-01-01

    Fishes use multiple flexible fins in order to move and maintain stability in a complex fluid environment. We used a new approach, a volumetric velocimetry imaging system, to provide the first instantaneous three-dimensional views of wake structures as they are produced by freely swimming fishes. This new technology allowed us to demonstrate conclusively the linked ring vortex wake pattern that is produced by the symmetrical (homocercal) tail of fishes, and to visualize for the first time the three-dimensional vortex wake interaction between the dorsal and anal fins and the tail. We found that the dorsal and anal fin wakes were rapidly (within one tail beat) assimilated into the caudal fin vortex wake. These results show that volumetric imaging of biologically generated flow patterns can reveal new features of locomotor dynamics, and provides an avenue for future investigations of the diversity of fish swimming patterns and their hydrodynamic consequences. PMID:21508026

  2. Volumetric imaging of fish locomotion.

    PubMed

    Flammang, Brooke E; Lauder, George V; Troolin, Daniel R; Strand, Tyson E

    2011-10-23

    Fishes use multiple flexible fins in order to move and maintain stability in a complex fluid environment. We used a new approach, a volumetric velocimetry imaging system, to provide the first instantaneous three-dimensional views of wake structures as they are produced by freely swimming fishes. This new technology allowed us to demonstrate conclusively the linked ring vortex wake pattern that is produced by the symmetrical (homocercal) tail of fishes, and to visualize for the first time the three-dimensional vortex wake interaction between the dorsal and anal fins and the tail. We found that the dorsal and anal fin wakes were rapidly (within one tail beat) assimilated into the caudal fin vortex wake. These results show that volumetric imaging of biologically generated flow patterns can reveal new features of locomotor dynamics, and provides an avenue for future investigations of the diversity of fish swimming patterns and their hydrodynamic consequences.

  3. PSF engineering in multifocus microscopy for increased depth volumetric imaging

    PubMed Central

    Hajj, Bassam; El Beheiry, Mohamed; Dahan, Maxime

    2016-01-01

    Imaging and localizing single molecules with high accuracy in a 3D volume is a challenging task. Here we combine multifocal microscopy, a recently developed volumetric imaging technique, with point spread function engineering to achieve an increased depth for single molecule imaging. Applications in 3D single molecule localization-based super-resolution imaging is shown over an axial depth of 4 µm as well as for the tracking of diffusing beads in a fluid environment over 8 µm. PMID:27231584

  4. Volumetric direct nuclear pumped laser

    NASA Technical Reports Server (NTRS)

    Jalufka, N. W.; Hohl, F.; Deyoung, R. J.; Williams, M. D. (Inventor)

    1978-01-01

    A volumetric direct nuclear pumped laser was developed in which the gas is a mixture of He-3 and a minority gas from the group of argon, krypton, xenon, chlorine and fluorine. The mixture of He-3 and the minority gas produces lasing with a minority gas concentration of from 0.01 to 10 percent argon, 1 percent krypton, 0.01 to 5 percent xenon and small concentrations of chlorine or fluorine.

  5. Skuller: A volumetric shape registration algorithm for modeling skull deformities.

    PubMed

    Sahillioğlu, Yusuf; Kavan, Ladislav

    2015-07-01

    We present an algorithm for volumetric registration of 3D solid shapes. In comparison to previous work on image based registration, our technique achieves higher efficiency by leveraging a template tetrahedral mesh. In contrast to point- and surface-based registration techniques, our method better captures volumetric nature of the data, such as bone thickness. We apply our algorithm to study pathological skull deformities caused by a particular condition, i.e., craniosynostosis. The input to our system is a pair of volumetric 3D shapes: a tetrahedral mesh and a voxelized object represented by a set of voxel cells segmented from computed tomography (CT) scans. Our general framework first performs a global registration and then launches a novel elastic registration process that uses as much volumetric information as possible while deforming the generic template tetrahedral mesh of a healthy human skull towards the underlying geometry of the voxel cells. Both data are high-resolution and differ by large non-rigid deformations. Our fully-automatic solution is fast and accurate, as compared with the state of the arts from the reconstruction and medical image registration fields. We use the resulting registration to match the ground-truth surfaces extracted from the medical data as well as to quantify the severity of the anatomical deformity.

  6. Pulse sequence for dynamic volumetric imaging of hyperpolarized metabolic products

    NASA Astrophysics Data System (ADS)

    Cunningham, Charles H.; Chen, Albert P.; Lustig, Michael; Hargreaves, Brian A.; Lupo, Janine; Xu, Duan; Kurhanewicz, John; Hurd, Ralph E.; Pauly, John M.; Nelson, Sarah J.; Vigneron, Daniel B.

    2008-07-01

    Dynamic nuclear polarization and dissolution of a 13C-labeled substrate enables the dynamic imaging of cellular metabolism. Spectroscopic information is typically acquired, making the acquisition of dynamic volumetric data a challenge. To enable rapid volumetric imaging, a spectral-spatial excitation pulse was designed to excite a single line of the carbon spectrum. With only a single resonance present in the signal, an echo-planar readout trajectory could be used to resolve spatial information, giving full volume coverage of 32 × 32 × 16 voxels every 3.5 s. This high frame rate was used to measure the different lactate dynamics in different tissues in a normal rat model and a mouse model of prostate cancer.

  7. Pulse Sequence for Dynamic Volumetric Imaging of Hyperpolarized Metabolic Products

    PubMed Central

    Cunningham, Charles H.; Chen, Albert P.; Lustig, Michael; Lupo, Janine; Xu, Duan; Kurhanewicz, John; Hurd, Ralph E.; Pauly, John M.; Nelson, Sarah J.; Vigneron, Daniel B.

    2011-01-01

    Dynamic nuclear polarization and dissolution of a 13C-labeled substrate enables the dynamic imaging of cellular metabolism. Spectroscopic information is typically acquired, making the acquisition of dynamic volumetric data a challenge. To enable rapid volumetric imaging, a spectral-spatial excitation pulse was designed to excite a single line of the carbon spectrum. With only a single resonance present in the signal, an echo-planar readout trajectory could be used to resolve spatial information, giving full volume coverage of 32 × 32 × 16 voxels every 3.5 seconds. This high frame rate was used to measure the different lactate dynamics in different tissues in a normal rat model and a mouse model of prostate cancer. PMID:18424203

  8. Continuous volumetric imaging via an optical phase-locked ultrasound lens

    PubMed Central

    Kong, Lingjie; Tang, Jianyong; Little, Justin P.; Yu, Yang; Lämmermann, Tim; Lin, Charles P.; Germain, Ronald N.; Cui, Meng

    2015-01-01

    In vivo imaging at high spatiotemporal resolution holds the key to the fundamental understanding of complex biological systems. Integrating an optical phase-locked ultrasound lens into a conventional two-photon fluorescence microscope, we achieved microsecond scale axial scanning, which enabled high-speed volumetric imaging. We applied this system to multicolor volumetric imaging of fast processes, including calcium dynamics in the cerebral cortex of behaving mice, and transient morphology changes and trafficking of immune cells. PMID:26167641

  9. Personalized heterogeneous deformable model for fast volumetric registration.

    PubMed

    Si, Weixin; Liao, Xiangyun; Wang, Qiong; Heng, Pheng Ann

    2017-02-20

    Biomechanical deformable volumetric registration can help improve safety of surgical interventions by ensuring the operations are extremely precise. However, this technique has been limited by the accuracy and the computational efficiency of patient-specific modeling. This study presents a tissue-tissue coupling strategy based on penalty method to model the heterogeneous behavior of deformable body, and estimate the personalized tissue-tissue coupling parameters in a data-driven way. Moreover, considering that the computational efficiency of biomechanical model is highly dependent on the mechanical resolution, a practical coarse-to-fine scheme is proposed to increase runtime efficiency. Particularly, a detail enrichment database is established in an offline fashion to represent the mapping relationship between the deformation results of high-resolution hexahedral mesh extracted from the raw medical data and a newly constructed low-resolution hexahedral mesh. At runtime, the mechanical behavior of human organ under interactions is simulated with this low-resolution hexahedral mesh, then the microstructures are synthesized in virtue of the detail enrichment database. The proposed method is validated by volumetric registration in an abdominal phantom compression experiments. Our personalized heterogeneous deformable model can well describe the coupling effects between different tissues of the phantom. Compared with high-resolution heterogeneous deformable model, the low-resolution deformable model with our detail enrichment database can achieve 9.4× faster, and the average target registration error is 3.42 mm, which demonstrates that the proposed method shows better volumetric registration performance than state-of-the-art. Our framework can well balance the precision and efficiency, and has great potential to be adopted in the practical augmented reality image-guided robotic systems.

  10. An automatic algorithm for detecting stent endothelialization from volumetric optical coherence tomography datasets

    NASA Astrophysics Data System (ADS)

    Bonnema, Garret T.; O'Halloran Cardinal, Kristen; Williams, Stuart K.; Barton, Jennifer K.

    2008-06-01

    Recent research has suggested that endothelialization of vascular stents is crucial to reducing the risk of late stent thrombosis. With a resolution of approximately 10 µm, optical coherence tomography (OCT) may be an appropriate imaging modality for visualizing the vascular response to a stent and measuring the percentage of struts covered with an anti-thrombogenic cellular lining. We developed an image analysis program to locate covered and uncovered stent struts in OCT images of tissue-engineered blood vessels. The struts were found by exploiting the highly reflective and shadowing characteristics of the metallic stent material. Coverage was evaluated by comparing the luminal surface with the depth of the strut reflection. Strut coverage calculations were compared to manual assessment of OCT images and epi-fluorescence analysis of the stented grafts. Based on the manual assessment, the strut identification algorithm operated with a sensitivity of 93% and a specificity of 99%. The strut coverage algorithm was 81% sensitive and 96% specific. The present study indicates that the program can automatically determine percent cellular coverage from volumetric OCT datasets of blood vessel mimics. The program could potentially be extended to assessments of stent endothelialization in native stented arteries.

  11. 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.

  12. Resolution of the cellular proteome of the nucleocapsid protein from a highly pathogenic isolate of porcine reproductive and respiratory syndrome virus identifies PARP-1 as a cellular target whose interaction is critical for virus biology.

    PubMed

    Liu, Long; Lear, Zoe; Hughes, David J; Wu, Weining; Zhou, En-min; Whitehouse, Adrian; Chen, Hongying; Hiscox, Julian A

    2015-03-23

    Porcine reproductive and respiratory syndrome virus (PRRSV) is a major threat to the swine industry and food security worldwide. The nucleocapsid (N) protein is a major structural protein of PRRSV. The primary function of this protein is to encapsidate the viral RNA genome, and it is also thought to participate in the modulation of host cell biology and recruitment of cellular factors to facilitate virus infection. In order to the better understand these latter roles the cellular interactome of PRRSV N protein was defined using label free quantitative proteomics. This identified several cellular factors that could interact with the N protein including poly [ADP-ribose] polymerase 1 (PARP-1), a cellular protein, which can add adenosine diphosphate ribose to a protein. Use of the PARP-1 small molecule inhibitor, 3-AB, in PRRSV infected cells demonstrated that PARP-1 was required and acted as an enhancer factor for virus biology. Serial growth of PRRSV in different concentrations of 3-AB did not yield viruses that were able to grow with wild type kinetics, suggesting that by targeting a cellular protein crucial for virus biology, resistant phenotypes did not emerge. This study provides further evidence that cellular proteins, which are critical for virus biology, can also be targeted to ablate virus growth and provide a high barrier for the emergence of drug resistance.

  13. Visualization and computer graphics on isotropically emissive volumetric displays.

    PubMed

    Mora, Benjamin; Maciejewski, Ross; Chen, Min; Ebert, David S

    2009-01-01

    The availability of commodity volumetric displays provides ordinary users with a new means of visualizing 3D data. Many of these displays are in the class of isotropically emissive light devices, which are designed to directly illuminate voxels in a 3D frame buffer, producing X-ray-like visualizations. While this technology can offer intuitive insight into a 3D object, the visualizations are perceptually different from what a computer graphics or visualization system would render on a 2D screen. This paper formalizes rendering on isotropically emissive displays and introduces a novel technique that emulates traditional rendering effects on isotropically emissive volumetric displays, delivering results that are much closer to what is traditionally rendered on regular 2D screens. Such a technique can significantly broaden the capability and usage of isotropically emissive volumetric displays. Our method takes a 3D dataset or object as the input, creates an intermediate light field, and outputs a special 3D volume dataset called a lumi-volume. This lumi-volume encodes approximated rendering effects in a form suitable for display with accumulative integrals along unobtrusive rays. When a lumi-volume is fed directly into an isotropically emissive volumetric display, it creates a 3D visualization with surface shading effects that are familiar to the users. The key to this technique is an algorithm for creating a 3D lumi-volume from a 4D light field. In this paper, we discuss a number of technical issues, including transparency effects due to the dimension reduction and sampling rates for light fields and lumi-volumes. We show the effectiveness and usability of this technique with a selection of experimental results captured from an isotropically emissive volumetric display, and we demonstrate its potential capability and scalability with computer-simulated high-resolution results.

  14. In vivo real-time volumetric synthetic aperture ultrasound imaging

    NASA Astrophysics Data System (ADS)

    Bouzari, Hamed; Rasmussen, Morten F.; Brandt, Andreas H.; Stuart, Matthias B.; Nikolov, Svetoslav; Jensen, Jørgen A.

    2015-03-01

    Synthetic aperture (SA) imaging can be used to achieve real-time volumetric ultrasound imaging using 2-D array transducers. The sensitivity of SA imaging is improved by maximizing the acoustic output, but one must consider the limitations of an ultrasound system, both technical and biological. This paper investigates the in vivo applicability and sensitivity of volumetric SA imaging. Utilizing the transmit events to generate a set of virtual point sources, a frame rate of 25 Hz for a 90° × 90° field-of-view was achieved. data were obtained using a 3.5 MHz 32 × 32 elements 2-D phased array transducer connected to the experimental scanner (SARUS). Proper scaling is applied to the excitation signal such that intensity levels are in compliance with the U.S. Food and Drug Administration regulations for in vivo ultrasound imaging. The measured Mechanical Index and spatial-peak-temporal-average intensity for parallel beam-forming (PB) are 0.83 and 377.5mW/cm2, and for SA are 0.48 and 329.5mW/cm2. A human kidney was volumetrically imaged with SA and PB techniques simultaneously. Two radiologists for evaluation of the volumetric SA were consulted by means of a questionnaire on the level of details perceivable in the beam-formed images. The comparison was against PB based on the in vivo data. The feedback from the domain experts indicates that volumetric SA images internal body structures with a better contrast resolution compared to PB at all positions in the entire imaged volume. Furthermore, the autocovariance of a homogeneous area in the in vivo SA data, had 23.5% smaller width at the half of its maximum value compared to PB.

  15. A volumetric three-dimensional digital light photoactivatable dye display

    NASA Astrophysics Data System (ADS)

    Patel, Shreya K.; Cao, Jian; Lippert, Alexander R.

    2017-07-01

    Volumetric three-dimensional displays offer spatially accurate representations of images with a 360° view, but have been difficult to implement due to complex fabrication requirements. Herein, a chemically enabled volumetric 3D digital light photoactivatable dye display (3D Light PAD) is reported. The operating principle relies on photoactivatable dyes that become reversibly fluorescent upon illumination with ultraviolet light. Proper tuning of kinetics and emission wavelengths enables the generation of a spatial pattern of fluorescent emission at the intersection of two structured light beams. A first-generation 3D Light PAD was fabricated using the photoactivatable dye N-phenyl spirolactam rhodamine B, a commercial picoprojector, an ultraviolet projector and a custom quartz imaging chamber. The system displays a minimum voxel size of 0.68 mm3, 200 μm resolution and good stability over repeated `on-off' cycles. A range of high-resolution 3D images and animations can be projected, setting the foundation for widely accessible volumetric 3D displays.

  16. A volumetric three-dimensional digital light photoactivatable dye display

    PubMed Central

    Patel, Shreya K.; Cao, Jian; Lippert, Alexander R.

    2017-01-01

    Volumetric three-dimensional displays offer spatially accurate representations of images with a 360° view, but have been difficult to implement due to complex fabrication requirements. Herein, a chemically enabled volumetric 3D digital light photoactivatable dye display (3D Light PAD) is reported. The operating principle relies on photoactivatable dyes that become reversibly fluorescent upon illumination with ultraviolet light. Proper tuning of kinetics and emission wavelengths enables the generation of a spatial pattern of fluorescent emission at the intersection of two structured light beams. A first-generation 3D Light PAD was fabricated using the photoactivatable dye N-phenyl spirolactam rhodamine B, a commercial picoprojector, an ultraviolet projector and a custom quartz imaging chamber. The system displays a minimum voxel size of 0.68 mm3, 200 μm resolution and good stability over repeated ‘on-off’ cycles. A range of high-resolution 3D images and animations can be projected, setting the foundation for widely accessible volumetric 3D displays. PMID:28695887

  17. Volumetric Acoustic Vector Intensity Probe

    NASA Technical Reports Server (NTRS)

    Klos, Jacob

    2006-01-01

    A new measurement tool capable of imaging the acoustic intensity vector throughout a large volume is discussed. This tool consists of an array of fifty microphones that form a spherical surface of radius 0.2m. A simultaneous measurement of the pressure field across all the microphones provides time-domain near-field holograms. Near-field acoustical holography is used to convert the measured pressure into a volumetric vector intensity field as a function of frequency on a grid of points ranging from the center of the spherical surface to a radius of 0.4m. The volumetric intensity is displayed on three-dimensional plots that are used to locate noise sources outside the volume. There is no restriction on the type of noise source that can be studied. The sphere is mobile and can be moved from location to location to hunt for unidentified noise sources. An experiment inside a Boeing 757 aircraft in flight successfully tested the ability of the array to locate low-noise-excited sources on the fuselage. Reference transducers located on suspected noise source locations can also be used to increase the ability of this device to separate and identify multiple noise sources at a given frequency by using the theory of partial field decomposition. The frequency range of operation is 0 to 1400Hz. This device is ideal for the study of noise sources in commercial and military transportation vehicles in air, on land and underwater.

  18. Analysis of the relationship between the volumetric soil moisture content and the NDVI from high resolution multi-spectral images for definition of vineyard management zones to improve irrigation

    NASA Astrophysics Data System (ADS)

    Martínez-Casasnovas, J. A.; Ramos, M. C.

    2009-04-01

    As suggested by previous research in the field of precision viticulture, intra-field yield variability is dependent on the variation of soil properties, and in particular the soil moisture content. Since the mapping in detail of this soil property for precision viticulture applications is highly costly, the objective of the present research is to analyse its relationship with the normalised difference vegetation index from high resolution satellite images to the use it in the definition of vineyard zonal management. The final aim is to improve irrigation in commercial vineyard blocks for better management of inputs and to deliver a more homogeneous fruit to the winery. The study was carried out in a vineyard block located in Raimat (NE Spain, Costers del Segre Designation of Origin). This is a semi-arid area with continental Mediterranean climate and a total annual precipitation between 300-400 mm. The vineyard block (4.5 ha) is planted with Syrah vines in a 3x2 m pattern. The vines are irrigated by means of drips under a partial root drying schedule. Initially, the irrigation sectors had a quadrangular distribution, with a size of about 1 ha each. Yield is highly variable within the block, presenting a coefficient of variation of 24.9%. For the measurement of the soil moisture content a regular sampling grid of 30 x 40 m was defined. This represents a sample density of 8 samples ha-1. At the nodes of the grid, TDR (Time Domain Reflectometer) probe tubes were permanently installed up to the 80 cm or up to reaching a contrasting layer. Multi-temporal measures were taken at different depths (each 20 cm) between November 2006 and December 2007. For each date, a map of the variability of the profile soil moisture content was interpolated by means of geostatistical analysis: from the measured values at the grid points the experimental variograms were computed and modelled and global block kriging (10 m squared blocks) undertaken with a grid spacing of 3 m x 3 m. On the

  19. Inkjet printing-based volumetric display projecting multiple full-colour 2D patterns

    NASA Astrophysics Data System (ADS)

    Hirayama, Ryuji; Suzuki, Tomotaka; Shimobaba, Tomoyoshi; Shiraki, Atsushi; Naruse, Makoto; Nakayama, Hirotaka; Kakue, Takashi; Ito, Tomoyoshi

    2017-04-01

    In this study, a method to construct a full-colour volumetric display is presented using a commercially available inkjet printer. Photoreactive luminescence materials are minutely and automatically printed as the volume elements, and volumetric displays are constructed with high resolution using easy-to-fabricate means that exploit inkjet printing technologies. The results experimentally demonstrate the first prototype of an inkjet printing-based volumetric display composed of multiple layers of transparent films that yield a full-colour three-dimensional (3D) image. Moreover, we propose a design algorithm with 3D structures that provide multiple different 2D full-colour patterns when viewed from different directions and experimentally demonstrate prototypes. It is considered that these types of 3D volumetric structures and their fabrication methods based on widely deployed existing printing technologies can be utilised as novel information display devices and systems, including digital signage, media art, entertainment and security.

  20. Volumetric apparel for visible female

    NASA Astrophysics Data System (ADS)

    Wu, Zhongke; Goh, Shuang R.; Kluenkaew, Orapan; Tang, Ming L.; Prakash, Edmond C.

    2000-03-01

    In this paper we present a new approach for apparel modeling based on voxel specifications that characterize control vertices and patch specifications. Our specification language is geared for robust apparel modeling by enforcing a strict control vertex coding via a combination of a static cross sectional slice and dynamic control polyhedron checking. Unlike most previous approach for apparel are not hard coded into the system. Instead we simply add suitable type definitions to the specification and define patterns to these types. We compile these specifications into a high performance volumetric apparel design system. Important components of our approach include efficient algorithms, for extraction of control vertices form slices of the volume and transformation of these vertices on sequences of such slices. Our system has been tested with the visible female system and we show a couple of examples generated using our approach.

  1. A reduced volumetric expansion factor plot

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.

    1979-01-01

    A reduced volumetric expansion factor plot was constructed for simple fluids which is suitable for engineering computations in heat transfer. Volumetric expansion factors were found useful in correlating heat transfer data over a wide range of operating conditions including liquids, gases and the near critical region.

  2. A reduced volumetric expansion factor plot

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.

    1979-01-01

    A reduced volumetric expansion factor plot has been constructed for simple fluids which is suitable for engineering computations in heat transfer. Volumetric expansion factors have been found useful in correlating heat transfer data over a wide range of operating conditions including liquids, gases and the near critical region.

  3. Parkinson's disease: diagnostic utility of volumetric imaging.

    PubMed

    Lin, Wei-Che; Chou, Kun-Hsien; Lee, Pei-Lin; Tsai, Nai-Wen; Chen, Hsiu-Ling; Hsu, Ai-Ling; Chen, Meng-Hsiang; Huang, Yung-Cheng; Lin, Ching-Po; Lu, Cheng-Hsien

    2017-04-01

    This paper aims to examine the effectiveness of structural imaging as an aid in the diagnosis of Parkinson's disease (PD). High-resolution T 1-weighted magnetic resonance imaging was performed in 72 patients with idiopathic PD (mean age, 61.08 years) and 73 healthy subjects (mean age, 58.96 years). The whole brain was parcellated into 95 regions of interest using composite anatomical atlases, and region volumes were calculated. Three diagnostic classifiers were constructed using binary multiple logistic regression modeling: the (i) basal ganglion prior classifier, (ii) data-driven classifier, and (iii) basal ganglion prior/data-driven hybrid classifier. Leave-one-out cross validation was used to unbiasedly evaluate the predictive accuracy of imaging features. Pearson's correlation analysis was further performed to correlate outcome measurement using the best PD classifier with disease severity. Smaller volume in susceptible regions is diagnostic for Parkinson's disease. Compared with the other two classifiers, the basal ganglion prior/data-driven hybrid classifier had the highest diagnostic reliability with a sensitivity of 74%, specificity of 75%, and accuracy of 74%. Furthermore, outcome measurement using this classifier was associated with disease severity. Brain structural volumetric analysis with multiple logistic regression modeling can be a complementary tool for diagnosing PD.

  4. Volumetric Optoacoustic Temperature Mapping in Photothermal Therapy.

    PubMed

    Landa, Francisco Javier Oyaga; Deán-Ben, Xosé Luís; Sroka, Ronald; Razansky, Daniel

    2017-08-29

    Photothermal therapy and ablation are commonplace medical procedures employed for treatment of tumors, vascular and brain abnormalities as well as other disorders that require selective destruction of tissues. Yet, accurate mapping of the dynamic temperature field distribution in the treated region represents an unmet clinical need, strongly affecting the clinical outcome of these interventions. We introduce a fast three-dimensional temperature mapping method based on real-time optoacoustic sensing of the treated region coupled with a thermal-diffusion-based model of heat distribution in tissues. Deviations of the optoacoustic temperature readings provided at 40  ms intervals remained below 10% in tissue-mimicking phantom experiments for temperature elevations above 3 °C, as validated by simultaneous thermocouple measurements. Performance of the new method to dynamically estimate the volumetric temperature distribution was further showcased in post-mortem mouse imaging experiments. The newly discovered capacity to non-invasively measure the temperature map in an entire treated volume with both high spatial and temporal resolutions holds potential for improving safety and efficacy of light-based therapeutic interventions.

  5. High-speed axial-scanning wide-field microscopy for volumetric particle tracking velocimetry

    NASA Astrophysics Data System (ADS)

    Chen, T.-H.; Ault, J. T.; Stone, H. A.; Arnold, C. B.

    2017-05-01

    The ability to understand and visualize complex flow structures in microfluidic and biological systems relies heavily on the resolving power of three-dimensional (3D) particle velocimetry techniques. We propose a simple technique for acquiring volumetric particle information with the potential for microsecond time resolution. By utilizing a fast varifocal lens in a modified wide-field microscope, we capture both volumetric and planar information with microsecond time resolution. The technique is demonstrated by tracking particle motions in the complex, three-dimensional flow in a high Reynolds number laminar flow at a branching arrow-shaped junction.

  6. Volumetric Video Compression for Interactive Playback★

    PubMed Central

    Sohn, Bong-Soo; Bajaj, Chandrajit; Siddavanahalli, Vinay

    2009-01-01

    We develop a volumetric video system which supports interactive browsing of compressed time-varying volumetric features (significant isosurfaces and interval volumes). Since the size of even one volumetric frame in a time-varying 3D data set is very large, transmission and on-line reconstruction are the main bottlenecks for interactive remote visualization of time-varying volume and surface data. We describe a compression scheme for encoding time-varying volumetric features in a unified way, which allows for on-line reconstruction and rendering. To increase the run-time decompression speed and compression ratio, we decompose the volume into small blocks and encode only the significant blocks that contribute to the isosurfaces and interval volumes. The results show that our compression scheme achieves high compression ratio with fast reconstruction, which is effective for client-side rendering of time-varying volumetric features. PMID:20072724

  7. Volumetric optoacoustic monitoring of endovenous laser treatments

    NASA Astrophysics Data System (ADS)

    Fehm, Thomas F.; Deán-Ben, Xosé L.; Schaur, Peter; Sroka, Ronald; Razansky, Daniel

    2016-03-01

    Chronic venous insufficiency (CVI) is one of the most common medical conditions with reported prevalence estimates as high as 30% in the adult population. Although conservative management with compression therapy may improve the symptoms associated with CVI, healing often demands invasive procedures. Besides established surgical methods like vein stripping or bypassing, endovenous laser therapy (ELT) emerged as a promising novel treatment option during the last 15 years offering multiple advantages such as less pain and faster recovery. Much of the treatment success hereby depends on monitoring of the treatment progression using clinical imaging modalities such as Doppler ultrasound. The latter however do not provide sufficient contrast, spatial resolution and three-dimensional imaging capacity which is necessary for accurate online lesion assessment during treatment. As a consequence, incidence of recanalization, lack of vessel occlusion and collateral damage remains highly variable among patients. In this study, we examined the capacity of volumetric optoacoustic tomography (VOT) for real-time monitoring of ELT using an ex-vivo ox foot model. ELT was performed on subcutaneous veins while optoacoustic signals were acquired and reconstructed in real-time and at a spatial resolution in the order of 200μm. VOT images showed spatio-temporal maps of the lesion progression, characteristics of the vessel wall, and position of the ablation fiber's tip during the pull back. It was also possible to correlate the images with the temperature elevation measured in the area adjacent to the ablation spot. We conclude that VOT is a promising tool for providing online feedback during endovenous laser therapy.

  8. Volumetric dimensional change of six direct core materials.

    PubMed

    Chutinan, Supattriya; Platt, Jeffrey A; Cochran, Michael A; Moore, B Keith

    2004-05-01

    This study evaluated the influence of water on the volumetric dimensional change of six direct placement core build-up materials by using Archimedes' principle. The effect on dimensional change due to the setting reaction was determined through the use of a silicone oil storage medium. The materials used were two dual-cured resin composites (CoreStore and Build-It FR), two chemically activated resin composites (CorePaste and Ti-Core), one metal-reinforced glass ionomer cement (Ketac-Silver), and one resin-modified glass ionomer (Fuji II LC Core). Using the manufacturers' instructions for each material, cylindrical specimens were prepared with dimensions of 7+/-0.1 mm in diameter and 2+/-0.1 mm in height. Each material had four groups (n = 5) based on storage conditions; silicone oil at 23 and 37 degrees C and distilled water at 23 and 37 degrees C. A 0.01 mg resolution balance was used to determine volumetric dimensional change using an Archimedean equation. Measurements were made 30 min after mixing, and at the time intervals of 1, 14, and 56 days. All materials exhibited dimensional change. Ketac-Silver had the most shrinkage in silicone oil and Fuji II LC showed the highest expansion in distilled water. The glass ionomer materials showed more change than did any of the resin composite materials. Current direct placement core materials show variation in the amount of volumetric dimensional change seen over a period of 56 days.

  9. Extended Kalman filtering for continuous volumetric MR-temperature imaging.

    PubMed

    Denis de Senneville, Baudouin; Roujol, Sébastien; Hey, Silke; Moonen, Chrit; Ries, Mario

    2013-04-01

    Real time magnetic resonance (MR) thermometry has evolved into the method of choice for the guidance of high-intensity focused ultrasound (HIFU) interventions. For this role, MR-thermometry should preferably have a high temporal and spatial resolution and allow observing the temperature over the entire targeted area and its vicinity with a high accuracy. In addition, the precision of real time MR-thermometry for therapy guidance is generally limited by the available signal-to-noise ratio (SNR) and the influence of physiological noise. MR-guided HIFU would benefit of the large coverage volumetric temperature maps, including characterization of volumetric heating trajectories as well as near- and far-field heating. In this paper, continuous volumetric MR-temperature monitoring was obtained as follows. The targeted area was continuously scanned during the heating process by a multi-slice sequence. Measured data and a priori knowledge of 3-D data derived from a forecast based on a physical model were combined using an extended Kalman filter (EKF). The proposed reconstruction improved the temperature measurement resolution and precision while maintaining guaranteed output accuracy. The method was evaluated experimentally ex vivo on a phantom, and in vivo on a porcine kidney, using HIFU heating. On the in vivo experiment, it allowed the reconstruction from a spatio-temporally under-sampled data set (with an update rate for each voxel of 1.143 s) to a 3-D dataset covering a field of view of 142.5×285×54 mm(3) with a voxel size of 3×3×6 mm(3) and a temporal resolution of 0.127 s. The method also provided noise reduction, while having a minimal impact on accuracy and latency.

  10. Innovations of wide-field optical-sectioning fluorescence microscopy: toward high-speed volumetric bio-imaging with simplicity

    NASA Astrophysics Data System (ADS)

    Yu, Jiun-Yann

    Optical microscopy has become an indispensable tool for biological researches since its invention, mostly owing to its sub-cellular spatial resolutions, non-invasiveness, instrumental simplicity, and the intuitive observations it provides. Nonetheless, obtaining reliable, quantitative spatial information from conventional wide-field optical microscopy is not always intuitive as it appears to be. This is because in the acquired images of optical microscopy the information about out-of-focus regions is spatially blurred and mixed with in-focus information. In other words, conventional wide-field optical microscopy transforms the three-dimensional spatial information, or volumetric information about the objects into a two-dimensional form in each acquired image, and therefore distorts the spatial information about the object. Several fluorescence holography-based methods have demonstrated the ability to obtain three-dimensional information about the objects, but these methods generally rely on decomposing stereoscopic visualizations to extract volumetric information and are unable to resolve complex 3-dimensional structures such as a multi-layer sphere. The concept of optical-sectioning techniques, on the other hand, is to detect only two-dimensional information about an object at each acquisition. Specifically, each image obtained by optical-sectioning techniques contains mainly the information about an optically thin layer inside the object, as if only a thin histological section is being observed at a time. Using such a methodology, obtaining undistorted volumetric information about the object simply requires taking images of the object at sequential depths. Among existing methods of obtaining volumetric information, the practicability of optical sectioning has made it the most commonly used and most powerful one in biological science. However, when applied to imaging living biological systems, conventional single-point-scanning optical-sectioning techniques often

  11. Volumetric assessment of cerebral asymmetries in dogs.

    PubMed

    Siniscalchi, Marcello; Franchini, Delia; Pepe, Anna M; Sasso, Raffaella; Dimatteo, Salvatore; Vallortigara, Giorgio; Quaranta, Angelo

    2011-09-01

    In the present study we quantified volumetric brain asymmetries from computed tomography (CT) scans in 12 healthy dogs, using a semi-automated technique for assessing in vivo structure asymmetry. Volumetric assessment of asymmetrical cerebral lateral ventricle (ALV) was also investigated. Our results showed that seven dogs exhibited a right hemisphere significantly greater than the left, two dogs had a left-greater-than-right hemisphere asymmetry, and finally two dogs displayed no significant brain volumetric asymmetry. This right-biased hemispheric asymmetry supports data reported previously using post-mortem morphological studies in both dogs and other mammalian species.

  12. Why Students Fail at Volumetric Analysis.

    ERIC Educational Resources Information Center

    Pickering, Miles

    1979-01-01

    Investigates the reasons for students' failure in an introductory volumetric analysis course by analyzing test papers and judging them against a hypothetical ideal method of grading laboratory techniques. (GA)

  13. [A new volumetric infusion pump (author's transl)].

    PubMed

    Radke, J; Wencker, K H

    1977-06-01

    Our experience with a new volumetric infusion pump "Tekmar T 92" is reported. Over a period of months the reported advantages of the instrument were investigated on three separate units. Some few disadvantages for routine use were observed.

  14. Volumetric analysis of abdominal aortic aneurysm

    NASA Astrophysics Data System (ADS)

    Baskin, Kevin M.; Kusnick, Catherine A.; Shamsolkottabi, Susanne; Lang, Elvira V.; Corson, J. D.; Stanford, William; Thompson, Brad H.; Hoffman, Eric A.

    1996-04-01

    The purpose of this study was to develop a valid, reliable and accurate system of measurement of abdominal aortic aneurysms, using volumetric analysis of x-ray computed tomographic data. This study evaluates illustrative cases, and compares measurements of AAA phantoms, using standard 2D versus volumetric methods. To validate the volumetric analysis, four phantom aneurysms were constructed in a range of diameters (4.5 - 7.0 cm) which presents the greatest management challenge to the clinician. These phantoms were imaged using a Toshiba Xpress SX helical CT. Separate scans were obtained at conventional (10 mm X 10 mm) and thin slice (5 mm X 5 mm) collimations. The thin slices were reconstructed at 2 mm intervals. Data from each of the 96 scans were interpreted using a standard 2D approach, then analyzed using task-oriented volumetric software. We evaluate patient assessments, and compare greatest outer diameters of phantoms, by standard versus volumetric methods. Qualitative differences between solutions based on standard versus volumetric analysis of illustrative patient cases are substantial. Expert radiologists' standard measurements of phantom aneurysms are highly reliable (r2 equals 0.901 - 0.958; p < 0.001), but biased toward significant overestimation of aneurysm diameters in the range of clinical interest. For the same phantoms, volumetric analysis was both more reliable (r2 equals 0.986 - 0.996; p < 0.001), and more accurate, with no significant bias in the range of interest. Volumetric analysis promotes selection of more valid management strategies, by providing vital information not otherwise available, and allowing more reliable and accurate assessment of abdominal aortic aneurysms. It is particularly valuable in the presence of aortic tortuosity, vessel eccentricity, and uncertain involvement of critical vessels.

  15. Laser Based 3D Volumetric Display System

    DTIC Science & Technology

    1993-03-01

    Literature, Costa Mesa, CA July 1983. 3. "A Real Time Autostereoscopic Multiplanar 3D Display System", Rodney Don Williams, Felix Garcia, Jr., Texas...8217 .- NUMBERS LASER BASED 3D VOLUMETRIC DISPLAY SYSTEM PR: CD13 0. AUTHOR(S) PE: N/AWIU: DN303151 P. Soltan, J. Trias, W. Robinson, W. Dahlke 7...laser generated 3D volumetric images on a rotating double helix, (where the 3D displays are computer controlled for group viewing with the naked eye

  16. Real-time volumetric scintillation dosimetry

    NASA Astrophysics Data System (ADS)

    Beddar, S.

    2015-01-01

    The goal of this brief review is to review the current status of real-time 3D scintillation dosimetry and what has been done so far in this area. The basic concept is to use a large volume of a scintillator material (liquid or solid) to measure or image the dose distributions from external radiation therapy (RT) beams in three dimensions. In this configuration, the scintillator material fulfills the dual role of being the detector and the phantom material in which the measurements are being performed. In this case, dose perturbations caused by the introduction of a detector within a phantom will not be at issue. All the detector configurations that have been conceived to date used a Charge-Coupled Device (CCD) camera to measure the light produced within the scintillator. In order to accurately measure the scintillation light, one must correct for various optical artefacts that arise as the light propagates from the scintillating centers through the optical chain to the CCD chip. Quenching, defined in its simplest form as a nonlinear response to high-linear energy transfer (LET) charged particles, is one of the disadvantages when such systems are used to measure the absorbed dose from high-LET particles such protons. However, correction methods that restore the linear dose response through the whole proton range have been proven to be effective for both liquid and plastic scintillators. Volumetric scintillation dosimetry has the potential to provide fast, high-resolution and accurate 3D imaging of RT dose distributions. Further research is warranted to optimize the necessary image reconstruction methods and optical corrections needed to achieve its full potential.

  17. Survey of Volumetric Grid Generators

    NASA Technical Reports Server (NTRS)

    Woo, Alex; Volakis, John; Hulbert, Greg; Case, Jeff; Presley, Leroy L. (Technical Monitor)

    1994-01-01

    This document is the result of an Internet Survey of Volumetric grid generators. As such we have included information from only the responses which were sent to us. After the initial publication and posting of this survey, we would encourage authors and users of grid generators to send further information. Here is the initial query posted to SIGGRID@nas and the USENET group sci.physics.computational.fluid-dynamics. Date: Sun, 30 Jan 94 11:37:52 -0800 From: woo (Alex Woo x6010 227-6 rm 315) Subject: Info Sought for Survey of Grid Generators I am collecting information and reviews of both government sponsored and commercial mesh generators for large scientific calculations, both block structured and unstructured. If you send me a review of a mesh generator, please indicate its availability and cost. If you are a commercial concern with information on a product, please also include references for possible reviewers. Please email to woo@ra-next.arc.nasa.gov. I will post a summary and probably write a short note for the IEEE Antennas and Propagation Magazine. Alex Woo, MS 227-6 woo@ames.arc.nasa.gov NASA Ames Research Center NASAMAIL ACWOO Moffett Field, CA 94035-1000 SPANET 24582::W00 (415) 604-6010 (FAX) 604-4357 fhplabs,decwrl,uunet)!ames!woo Disclaimer: These are not official statements of NASA or EMCC. We did not include all the submitted text here. Instead we have created a database entry in the freely available and widely used BIBTeX format which has an Uniform Resource Locator (URL) field pointing to more details. The BIBTeX database is modeled after those available from the BIBNET project at University of Utah.

  18. Volumetric B1 (+) mapping of the brain at 7T using DREAM.

    PubMed

    Nehrke, Kay; Versluis, Maarten J; Webb, Andrew; Börnert, Peter

    2014-01-01

    To tailor and optimize the Dual Refocusing Echo Acquisition Mode (DREAM) approach for volumetric B1 (+) mapping of the brain at 7T. A new DREAM echo timing scheme based on the virtual stimulated echo was derived to minimize potential effects of transverse relaxation. Furthermore, the DREAM B1 (+) mapping performance was investigated in simulations and experimentally in phantoms and volunteers for volumetric applications, studying and optimizing the accuracy of the sequence with respect to saturation effects, slice profile imperfections, and T1 and T2 relaxation. Volumetric brain protocols were compiled for different isotropic resolutions (5-2.5 mm) and SENSE factors, and were studied in vivo for different RF drive modes (circular/linear polarization) and the application of dielectric pads. Volumetric B1 (+) maps with good SNR at 2.5 mm isotropic resolution were acquired in about 20 s or less. The specific absorption rate was well below the safety limits for all scans. Mild flow artefacts were observed in the large vessels. Moreover, a slight contrast in the ventricle was observed in the B1 (+) maps, which could be attributed to T1 and T2 relaxation effects. DREAM enables safe, very fast, and robust volumetric B1 (+) mapping of the brain at ultrahigh fields. Copyright © 2013 Wiley Periodicals, Inc.

  19. In vivo volumetric imaging of subcutaneous microvasculature by photoacoustic microscopy

    NASA Astrophysics Data System (ADS)

    Zhang, Hao F.; Maslov, Konstantin; Li, Meng-Lin; Stoica, George; Wang, Lihong V.

    2006-10-01

    Photoacoustic microscopy was developed to achieve volumetric imaging of the anatomy and functions of the subcutaneous microvasculature in both small animals and humans in vivo with high spatial resolution and high signal-to-background ratio. By following the skin contour in raster scanning, the ultrasonic transducer maintains focusing in the region of interest. Furthermore, off-focus lateral resolution is improved by using a synthetic-aperture focusing technique based on the virtual point detector concept. Structural images are acquired in both rats and humans, whereas functional images representing hemoglobin oxygen saturation are acquired in rats. After multiscale vesselness filtering, arterioles and venules in the image are separated based on the imaged oxygen saturation levels. Detailed structural information, such as vessel depth and spatial orientation, are revealed by volume rendering.

  20. Volumetric label-free imaging and 3D reconstruction of mammalian cochlea based on two-photon excitation fluorescence microscopy

    NASA Astrophysics Data System (ADS)

    Zhang, Xianzeng; Geng, Yang; Ye, Qing; Zhan, Zhenlin; Xie, Shusen

    2013-11-01

    The visualization of the delicate structure and spatial relationship of intracochlear sensory cells has relied on the laborious procedures of tissue excision, fixation, sectioning and staining for light and electron microscopy. Confocal microscopy is advantageous for its high resolution and deep penetration depth, yet disadvantageous due to the necessity of exogenous labeling. In this study, we present the volumetric imaging of rat cochlea without exogenous dyes using a near-infrared femtosecond laser as the excitation mechanism and endogenous two-photon excitation fluorescence (TPEF) as the contrast mechanism. We find that TPEF exhibits strong contrast, allowing cellular and even subcellular resolution imaging of the cochlea, differentiating cell types, visualizing delicate structures and the radial nerve fiber. Our results further demonstrate that 3D reconstruction rendered with z-stacks of optical sections enables better revealment of fine structures and spatial relationships, and easily performed morphometric analysis. The TPEF-based optical biopsy technique provides great potential for new and sensitive diagnostic tools for hearing loss or hearing disorders, especially when combined with fiber-based microendoscopy.

  1. Volumetric 3D Display System with Static Screen

    NASA Technical Reports Server (NTRS)

    Geng, Jason

    2011-01-01

    Current display technology has relied on flat, 2D screens that cannot truly convey the third dimension of visual information: depth. In contrast to conventional visualization that is primarily based on 2D flat screens, the volumetric 3D display possesses a true 3D display volume, and places physically each 3D voxel in displayed 3D images at the true 3D (x,y,z) spatial position. Each voxel, analogous to a pixel in a 2D image, emits light from that position to form a real 3D image in the eyes of the viewers. Such true volumetric 3D display technology provides both physiological (accommodation, convergence, binocular disparity, and motion parallax) and psychological (image size, linear perspective, shading, brightness, etc.) depth cues to human visual systems to help in the perception of 3D objects. In a volumetric 3D display, viewers can watch the displayed 3D images from a completely 360 view without using any special eyewear. The volumetric 3D display techniques may lead to a quantum leap in information display technology and can dramatically change the ways humans interact with computers, which can lead to significant improvements in the efficiency of learning and knowledge management processes. Within a block of glass, a large amount of tiny dots of voxels are created by using a recently available machining technique called laser subsurface engraving (LSE). The LSE is able to produce tiny physical crack points (as small as 0.05 mm in diameter) at any (x,y,z) location within the cube of transparent material. The crack dots, when illuminated by a light source, scatter the light around and form visible voxels within the 3D volume. The locations of these tiny voxels are strategically determined such that each can be illuminated by a light ray from a high-resolution digital mirror device (DMD) light engine. The distribution of these voxels occupies the full display volume within the static 3D glass screen. This design eliminates any moving screen seen in previous

  2. Quantitative volumetric Raman imaging of three dimensional cell cultures

    PubMed Central

    Kallepitis, Charalambos; Bergholt, Mads S.; Mazo, Manuel M.; Leonardo, Vincent; Skaalure, Stacey C.; Maynard, Stephanie A.; Stevens, Molly M.

    2017-01-01

    The ability to simultaneously image multiple biomolecules in biologically relevant three-dimensional (3D) cell culture environments would contribute greatly to the understanding of complex cellular mechanisms and cell–material interactions. Here, we present a computational framework for label-free quantitative volumetric Raman imaging (qVRI). We apply qVRI to a selection of biological systems: human pluripotent stem cells with their cardiac derivatives, monocytes and monocyte-derived macrophages in conventional cell culture systems and mesenchymal stem cells inside biomimetic hydrogels that supplied a 3D cell culture environment. We demonstrate visualization and quantification of fine details in cell shape, cytoplasm, nucleus, lipid bodies and cytoskeletal structures in 3D with unprecedented biomolecular specificity for vibrational microspectroscopy. PMID:28327660

  3. Quantitative volumetric Raman imaging of three dimensional cell cultures

    NASA Astrophysics Data System (ADS)

    Kallepitis, Charalambos; Bergholt, Mads S.; Mazo, Manuel M.; Leonardo, Vincent; Skaalure, Stacey C.; Maynard, Stephanie A.; Stevens, Molly M.

    2017-03-01

    The ability to simultaneously image multiple biomolecules in biologically relevant three-dimensional (3D) cell culture environments would contribute greatly to the understanding of complex cellular mechanisms and cell-material interactions. Here, we present a computational framework for label-free quantitative volumetric Raman imaging (qVRI). We apply qVRI to a selection of biological systems: human pluripotent stem cells with their cardiac derivatives, monocytes and monocyte-derived macrophages in conventional cell culture systems and mesenchymal stem cells inside biomimetic hydrogels that supplied a 3D cell culture environment. We demonstrate visualization and quantification of fine details in cell shape, cytoplasm, nucleus, lipid bodies and cytoskeletal structures in 3D with unprecedented biomolecular specificity for vibrational microspectroscopy.

  4. Temporal Coding of Volumetric Imagery

    NASA Astrophysics Data System (ADS)

    Llull, Patrick Ryan

    'Image volumes' refer to realizations of images in other dimensions such as time, spectrum, and focus. Recent advances in scientific, medical, and consumer applications demand improvements in image volume capture. Though image volume acquisition continues to advance, it maintains the same sampling mechanisms that have been used for decades; every voxel must be scanned and is presumed independent of its neighbors. Under these conditions, improving performance comes at the cost of increased system complexity, data rates, and power consumption. This dissertation explores systems and methods capable of efficiently improving sensitivity and performance for image volume cameras, and specifically proposes several sampling strategies that utilize temporal coding to improve imaging system performance and enhance our awareness for a variety of dynamic applications. Video cameras and camcorders sample the video volume (x,y,t) at fixed intervals to gain understanding of the volume's temporal evolution. Conventionally, one must reduce the spatial resolution to increase the framerate of such cameras. Using temporal coding via physical translation of an optical element known as a coded aperture, the compressive temporal imaging (CACTI) camera emonstrates a method which which to embed the temporal dimension of the video volume into spatial (x,y) measurements, thereby greatly improving temporal resolution with minimal loss of spatial resolution. This technique, which is among a family of compressive sampling strategies developed at Duke University, temporally codes the exposure readout functions at the pixel level. Since video cameras nominally integrate the remaining image volume dimensions (e.g. spectrum and focus) at capture time, spectral (x,y,t,lambda) and focal (x,y,t,z) image volumes are traditionally captured via sequential changes to the spectral and focal state of the system, respectively. The CACTI camera's ability to embed video volumes into images leads to exploration

  5. A volumetric flask as a projector

    NASA Astrophysics Data System (ADS)

    Limsuwan, P.; Asanithi, P.; Thongpool, V.; Piriyawong, V.; Limsuwan, S.

    2012-03-01

    A lens based on liquid in the confined volume of a volumetric flask was presented as a potential projector to observe microscopic floating organisms or materials. In this experiment, a mosquito larva from a natural pond was selected as a demonstration sample. By shining a light beam from a laser pointer of any visible wavelength through the volumetric flask filled with liquid, the movements of floating objects were clearly observed on a screen. The magnification was simply controlled by changing either the volume of the flask or the distance of the screen from the flask.

  6. Nonequilibrium volumetric response of shocked polymers

    SciTech Connect

    Clements, B E

    2009-01-01

    Polymers are well known for their non-equilibrium deviatoric behavior. However, investigations involving both high rate shock experiments and equilibrium measured thermodynamic quantities remind us that the volumetric behavior also exhibits a non-equilibrium response. Experiments supporting the notion of a non-equilibrium volumetric behavior will be summarized. Following that discussion, a continuum-level theory is proposed that will account for both the equilibrium and non-equilibrium response. Upon finding agreement with experiment, the theory is used to study the relaxation of a shocked polymer back towards its shocked equilibrium state.

  7. Motion correction for cellular-resolution multi-photon fluorescence microscopy imaging of awake head-restrained mice using speed embedded HMM.

    PubMed

    Chen, Taoyi; Xue, Zhong; Wang, Changhong; Qu, Zhenshen; Wong, Kelvin K; Wong, Stephen T C

    2012-04-01

    Multi-photon fluorescence microscopy (MFM) captures high-resolution fluorescence image sequences and can be used for the intact brain imaging of small animals. Recently, it has been extended from anesthetized and head-stabilized mice to awake and head-restrained ones for in vivo neurological study. In these applications, motion correction is an important pre-processing step since brain pulsation and body movement can cause motion artifact and prevent stable serial image acquisition at such high spatial resolution. This paper proposes a speed embedded Hidden Markov model (SEHMM) for motion correction in MFM imaging of awake head-restrained mice. The algorithm extends the traditional Hidden Markov model (HMM) method by embedding a motion prediction model to better estimate the state transition probability. The novelty of the method lies in using adaptive probability to estimate the linear motion, while the state-of-the-art method assumes that the highest probability is assigned to the case with no motion. In experiments we demonstrated that SEHMM is more accurate than the traditional HMM using both simulated and real MFM image sequences.

  8. High resolution respirometry analysis of polyethylenimine-mediated mitochondrial energy crisis and cellular stress: Mitochondrial proton leak and inhibition of the electron transport system.

    PubMed

    Hall, Arnaldur; Larsen, Anna K; Parhamifar, Ladan; Meyle, Kathrine D; Wu, Lin-Ping; Moghimi, S Moein

    2013-10-01

    Polyethylenimines (PEIs) are highly efficient non-viral transfectants, but can induce cell death through poorly understood necrotic and apoptotic processes as well as autophagy. Through high resolution respirometry studies in H1299 cells we demonstrate that the 25kDa branched polyethylenimine (25k-PEI-B), in a concentration and time-dependent manner, facilitates mitochondrial proton leak and inhibits the electron transport system. These events were associated with gradual reduction of the mitochondrial membrane potential and mitochondrial ATP synthesis. The intracellular ATP levels further declined as a consequence of PEI-mediated plasma membrane damage and subsequent ATP leakage to the extracellular medium. Studies with freshly isolated mouse liver mitochondria corroborated with bioenergetic findings and demonstrated parallel polycation concentration- and time-dependent changes in state 2 and state 4o oxygen flux as well as lowered ADP phosphorylation (state 3) and mitochondrial ATP synthesis. Polycation-mediated reduction of electron transport system activity was further demonstrated in 'broken mitochondria' (freeze-thawed mitochondrial preparations). Moreover, by using both high-resolution respirometry and spectrophotometry analysis of cytochrome c oxidase activity we were able to identify complex IV (cytochrome c oxidase) as a likely specific site of PEI mediated inhibition within the electron transport system. Unraveling the mechanisms of PEI-mediated mitochondrial energy crisis is central for combinatorial design of safer polymeric non-viral gene delivery systems.

  9. Whole-Organism Cellular Pathology: A Systems Approach to Phenomics.

    PubMed

    Cheng, K C; Katz, S R; Lin, A Y; Xin, X; Ding, Y

    2016-01-01

    Phenotype is defined as the state of an organism resulting from interactions between genes, environment, disease, molecular mechanisms, and chance. The purpose of the emerging field of phenomics is to systematically determine and measure phenotypes across biology for the sake of understanding. Phenotypes can affect more than one cell type and life stage, so ideal phenotyping would include the state of every cell type within the context of both tissue architecture and the whole organism at each life stage. In medicine, high-resolution anatomic assessment of phenotype is obtained from histology. Histology's interpretative power, codified by Virchow as cellular pathology, is derived from its ability to discern diagnostic and characteristic cellular changes in diseased tissues. Cellular pathology is observed in every major human disease and relies on the ability of histology to detect cellular change in any cell type due to unbiased pan-cellular staining, even in optically opaque tissues. Our laboratory has shown that histology is far more sensitive than stereomicroscopy for detecting phenotypes in zebrafish mutants. Those studies have also shown that more complete sampling, greater consistency in sample orientation, and the inclusion of phenotypes extending over longer length scales would provide greater coverage of common phenotypes. We are developing technical approaches to achieve an ideal detection of cellular pathology using an improved form of X-ray microtomography that retains the strengths and addresses the weaknesses of histology as a screening tool. We are using zebrafish as a vertebrate model based on the overlaps between zebrafish and mammalian tissue architecture, and a body size small enough to allow whole-organism, volumetric imaging at cellular resolution. Automation of whole-organism phenotyping would greatly increase the value of phenomics. Potential societal benefits would include reduction in the cost of drug development, a reduction in the

  10. Volumetric three-dimensional display system with rasterization hardware

    NASA Astrophysics Data System (ADS)

    Favalora, Gregg E.; Dorval, Rick K.; Hall, Deirdre M.; Giovinco, Michael; Napoli, Joshua

    2001-06-01

    An 8-color multiplanar volumetric display is being developed by Actuality Systems, Inc. It will be capable of utilizing an image volume greater than 90 million voxels, which we believe is the greatest utilizable voxel set of any volumetric display constructed to date. The display is designed to be used for molecular visualization, mechanical CAD, e-commerce, entertainment, and medical imaging. As such, it contains a new graphics processing architecture, novel high-performance line- drawing algorithms, and an API similar to a current standard. Three-dimensional imagery is created by projecting a series of 2-D bitmaps ('image slices') onto a diffuse screen that rotates at 600 rpm. Persistence of vision fuses the slices into a volume-filling 3-D image. A modified three-panel Texas Instruments projector provides slices at approximately 4 kHz, resulting in 8-color 3-D imagery comprised of roughly 200 radially-disposed slices which are updated at 20 Hz. Each slice has a resolution of 768 by 768 pixels, subtending 10 inches. An unusual off-axis projection scheme incorporating tilted rotating optics is used to maintain good focus across the projection screen. The display electronics includes a custom rasterization architecture which converts the user's 3- D geometry data into image slices, as well as 6 Gbits of DDR SDRAM graphics memory.

  11. A Volumetric Flask as a Projector

    ERIC Educational Resources Information Center

    Limsuwan, P.; Asanithi, P.; Thongpool, V.; Piriyawong, V.; Limsuwan, S.

    2012-01-01

    A lens based on liquid in the confined volume of a volumetric flask was presented as a potential projector to observe microscopic floating organisms or materials. In this experiment, a mosquito larva from a natural pond was selected as a demonstration sample. By shining a light beam from a laser pointer of any visible wavelength through the…

  12. Indexing Volumetric Shapes with Matching and Packing.

    PubMed

    Koes, David Ryan; Camacho, Carlos J

    2015-04-01

    We describe a novel algorithm for bulk-loading an index with high-dimensional data and apply it to the problem of volumetric shape matching. Our matching and packing algorithm is a general approach for packing data according to a similarity metric. First an approximate k-nearest neighbor graph is constructed using vantage-point initialization, an improvement to previous work that decreases construction time while improving the quality of approximation. Then graph matching is iteratively performed to pack related items closely together. The end result is a dense index with good performance. We define a new query specification for shape matching that uses minimum and maximum shape constraints to explicitly specify the spatial requirements of the desired shape. This specification provides a natural language for performing volumetric shape matching and is readily supported by the geometry-based similarity search (GSS) tree, an indexing structure that maintains explicit representations of volumetric shape. We describe our implementation of a GSS tree for volumetric shape matching and provide a comprehensive evaluation of parameter sensitivity, performance, and scalability. Compared to previous bulk-loading algorithms, we find that matching and packing can construct a GSS-tree index in the same amount of time that is denser, flatter, and better performing, with an observed average performance improvement of 2X.

  13. Indexing Volumetric Shapes with Matching and Packing

    PubMed Central

    Koes, David Ryan; Camacho, Carlos J.

    2014-01-01

    We describe a novel algorithm for bulk-loading an index with high-dimensional data and apply it to the problem of volumetric shape matching. Our matching and packing algorithm is a general approach for packing data according to a similarity metric. First an approximate k-nearest neighbor graph is constructed using vantage-point initialization, an improvement to previous work that decreases construction time while improving the quality of approximation. Then graph matching is iteratively performed to pack related items closely together. The end result is a dense index with good performance. We define a new query specification for shape matching that uses minimum and maximum shape constraints to explicitly specify the spatial requirements of the desired shape. This specification provides a natural language for performing volumetric shape matching and is readily supported by the geometry-based similarity search (GSS) tree, an indexing structure that maintains explicit representations of volumetric shape. We describe our implementation of a GSS tree for volumetric shape matching and provide a comprehensive evaluation of parameter sensitivity, performance, and scalability. Compared to previous bulk-loading algorithms, we find that matching and packing can construct a GSS-tree index in the same amount of time that is denser, flatter, and better performing, with an observed average performance improvement of 2X. PMID:26085707

  14. Uncertainty quantification in volumetric Particle Image Velocimetry

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Sayantan; Charonko, John; Vlachos, Pavlos

    2016-11-01

    Particle Image Velocimetry (PIV) uncertainty quantification is challenging due to coupled sources of elemental uncertainty and complex data reduction procedures in the measurement chain. Recent developments in this field have led to uncertainty estimation methods for planar PIV. However, no framework exists for three-dimensional volumetric PIV. In volumetric PIV the measurement uncertainty is a function of reconstructed three-dimensional particle location that in turn is very sensitive to the accuracy of the calibration mapping function. Furthermore, the iterative correction to the camera mapping function using triangulated particle locations in space (volumetric self-calibration) has its own associated uncertainty due to image noise and ghost particle reconstructions. Here we first quantify the uncertainty in the triangulated particle position which is a function of particle detection and mapping function uncertainty. The location uncertainty is then combined with the three-dimensional cross-correlation uncertainty that is estimated as an extension of the 2D PIV uncertainty framework. Finally the overall measurement uncertainty is quantified using an uncertainty propagation equation. The framework is tested with both simulated and experimental cases. For the simulated cases the variation of estimated uncertainty with the elemental volumetric PIV error sources are also evaluated. The results show reasonable prediction of standard uncertainty with good coverage.

  15. A Volumetric Flask as a Projector

    ERIC Educational Resources Information Center

    Limsuwan, P.; Asanithi, P.; Thongpool, V.; Piriyawong, V.; Limsuwan, S.

    2012-01-01

    A lens based on liquid in the confined volume of a volumetric flask was presented as a potential projector to observe microscopic floating organisms or materials. In this experiment, a mosquito larva from a natural pond was selected as a demonstration sample. By shining a light beam from a laser pointer of any visible wavelength through the…

  16. Bronchoalveolar lavage cellular analyses in conjunction with high-resolution computed tomography imaging as a diagnostic intervention for patients with suspected interstitial lung disease.

    PubMed

    Chockalingam, Ammaiyappan; Duraiswamy, Ranganathan; Jagadeesan, Madhavan

    2016-01-01

    Bronchoalveolar lavage (BAL) has gained acceptance for diagnosis of Interstitial lung disease (ILD). The advent of high-resolution computed tomography (HRCT) has reduced the clinical utility of BAL. This work has utilized the recommendations of the American Thoracic Society (ATS) to optimize BAL and the findings have been associated with clinical examination and HRCT to precisely narrow down the cause of ILD. BAL was performed on ILD suspects at the target site chosen based on HRCT. The procedure, transport, processing, and analysis of BAL fluid were performed as per the ATS guidelines. The clinical data, HRCT findings and BAL report were used to narrow down the diagnosis of ILD. The statistical analysis was performed to assess the significance. The BAL procedure was optimized as per the recommendations of the ATS. In a cohort of 50 patients, Idiopathic pulmonary fibrosis, (8) hypersensitivity pneumonitis, (17) connective tissue disorder, (9) sarcoidosis, (3) pneumoconiosis, (5) acute respiratory distress syndrome, (2) eosinophilic lung disease (2) and lymphangitic carcinomatosa, (2) aspiration bronchiolitis (1) and pulmonary histiocytosis (1) were diagnosed. Statistically significant variation in differential counts was found in different ILDs. The different ILDs were classified based on the criteria described by the ATS. BAL along with clinical and HRCT findings improved the diagnostic accuracy by incorporating, the acute or chronic nature of the disease and the cause for acute exacerbation, which helped in the better management of ILDs.

  17. Integrated adaptive optics optical coherence tomography and adaptive optics scanning laser ophthalmoscope system for simultaneous cellular resolution in vivo retinal imaging

    PubMed Central

    Zawadzki, Robert J.; Jones, Steven M.; Pilli, Suman; Balderas-Mata, Sandra; Kim, Dae Yu; Olivier, Scot S.; Werner, John S.

    2011-01-01

    We describe an ultrahigh-resolution (UHR) retinal imaging system that combines adaptive optics Fourier-domain optical coherence tomography (AO-OCT) with an adaptive optics scanning laser ophthalmoscope (AO-SLO) to allow simultaneous data acquisition by the two modalities. The AO-SLO subsystem was integrated into the previously described AO-UHR OCT instrument with minimal changes to the latter. This was done in order to ensure optimal performance and image quality of the AO- UHR OCT. In this design both imaging modalities share most of the optical components including a common AO-subsystem and vertical scanner. One of the benefits of combining Fd-OCT with SLO includes automatic co-registration between two acquisition channels for direct comparison between retinal structures imaged by both modalities (e.g., photoreceptor mosaics or microvasculature maps). Because of differences in the detection scheme of the two systems, this dual imaging modality instrument can provide insight into retinal morphology and potentially function, that could not be accessed easily by a single system. In this paper we describe details of the components and parameters of the combined instrument, including incorporation of a novel membrane magnetic deformable mirror with increased stroke and actuator count used as a single wavefront corrector. We also discuss laser safety calculations for this multimodal system. Finally, retinal images acquired in vivo with this system are presented. PMID:21698028

  18. Integrated adaptive optics optical coherence tomography and adaptive optics scanning laser ophthalmoscope system for simultaneous cellular resolution in vivo retinal imaging.

    PubMed

    Zawadzki, Robert J; Jones, Steven M; Pilli, Suman; Balderas-Mata, Sandra; Kim, Dae Yu; Olivier, Scot S; Werner, John S

    2011-06-01

    We describe an ultrahigh-resolution (UHR) retinal imaging system that combines adaptive optics Fourier-domain optical coherence tomography (AO-OCT) with an adaptive optics scanning laser ophthalmoscope (AO-SLO) to allow simultaneous data acquisition by the two modalities. The AO-SLO subsystem was integrated into the previously described AO-UHR OCT instrument with minimal changes to the latter. This was done in order to ensure optimal performance and image quality of the AO- UHR OCT. In this design both imaging modalities share most of the optical components including a common AO-subsystem and vertical scanner. One of the benefits of combining Fd-OCT with SLO includes automatic co-registration between two acquisition channels for direct comparison between retinal structures imaged by both modalities (e.g., photoreceptor mosaics or microvasculature maps). Because of differences in the detection scheme of the two systems, this dual imaging modality instrument can provide insight into retinal morphology and potentially function, that could not be accessed easily by a single system. In this paper we describe details of the components and parameters of the combined instrument, including incorporation of a novel membrane magnetic deformable mirror with increased stroke and actuator count used as a single wavefront corrector. We also discuss laser safety calculations for this multimodal system. Finally, retinal images acquired in vivo with this system are presented.

  19. Volumetric sub-surface imaging using spectrally encoded endoscopy.

    PubMed

    Yelin, D; Bouma, B E; Tearney, G J

    2008-02-04

    Endoscopic imaging below tissue surfaces and through turbid media may provide improved diagnostic capabilities and visibility in surgical settings. Spectrally encoded endoscopy (SEE) is a recently developed method that utilizes a single optical fiber, miniature optics and a diffractive grating for high-speed imaging through small diameter, flexible endoscopic probes. SEE has also been shown to provide three-dimensional topological imaging capabilities. In this paper, we have configured SEE to additionally image beneath tissue surfaces, by increasing the system's sensitivity and acquiring the complex spectral density for each spectrally resolved point on the sample. In order to demonstrate the capability of SEE to obtain subsurface information, we have utilized the system to image a resolution target through intralipid solution, and conduct volumetric imaging of a mouse embryo and excised human middle-ear ossicles. Our results demonstrate that real-time subsurface imaging is possible with this miniature endoscopy technique.

  20. Skeletal muscle tissue engineering: strategies for volumetric constructs.

    PubMed

    Cittadella Vigodarzere, Giorgio; Mantero, Sara

    2014-01-01

    Skeletal muscle tissue is characterized by high metabolic requirements, defined structure and high regenerative potential. As such, it constitutes an appealing platform for tissue engineering to address volumetric defects, as proven by recent works in this field. Several issues common to all engineered constructs constrain the variety of tissues that can be realized in vitro, principal among them the lack of a vascular system and the absence of reliable cell sources; as it is, the only successful tissue engineering constructs are not characterized by active function, present limited cellular survival at implantation and possess low metabolic requirements. Recently, functionally competent constructs have been engineered, with vascular structures supporting their metabolic requirements. In addition to the use of biochemical cues, physical means, mechanical stimulation and the application of electric tension have proven effective in stimulating the differentiation of cells and the maturation of the constructs; while the use of co-cultures provided fine control of cellular developments through paracrine activity. This review will provide a brief analysis of some of the most promising improvements in the field, with particular attention to the techniques that could prove easily transferable to other branches of tissue engineering.

  1. Skeletal muscle tissue engineering: strategies for volumetric constructs

    PubMed Central

    Cittadella Vigodarzere, Giorgio; Mantero, Sara

    2014-01-01

    Skeletal muscle tissue is characterized by high metabolic requirements, defined structure and high regenerative potential. As such, it constitutes an appealing platform for tissue engineering to address volumetric defects, as proven by recent works in this field. Several issues common to all engineered constructs constrain the variety of tissues that can be realized in vitro, principal among them the lack of a vascular system and the absence of reliable cell sources; as it is, the only successful tissue engineering constructs are not characterized by active function, present limited cellular survival at implantation and possess low metabolic requirements. Recently, functionally competent constructs have been engineered, with vascular structures supporting their metabolic requirements. In addition to the use of biochemical cues, physical means, mechanical stimulation and the application of electric tension have proven effective in stimulating the differentiation of cells and the maturation of the constructs; while the use of co-cultures provided fine control of cellular developments through paracrine activity. This review will provide a brief analysis of some of the most promising improvements in the field, with particular attention to the techniques that could prove easily transferable to other branches of tissue engineering. PMID:25295011

  2. VOLUMETRIC POLYMERIZATION SHRINKAGE OF CONTEMPORARY COMPOSITE RESINS

    PubMed Central

    Nagem, Halim; Nagem, Haline Drumond; Francisconi, Paulo Afonso Silveira; Franco, Eduardo Batista; Mondelli, Rafael Francisco Lia; Coutinho, Kennedy Queiroz

    2007-01-01

    The polymerization shrinkage of composite resins may affect negatively the clinical outcome of the restoration. Extensive research has been carried out to develop new formulations of composite resins in order to provide good handling characteristics and some dimensional stability during polymerization. The purpose of this study was to analyze, in vitro, the magnitude of the volumetric polymerization shrinkage of 7 contemporary composite resins (Definite, Suprafill, SureFil, Filtek Z250, Fill Magic, Alert, and Solitaire) to determine whether there are differences among these materials. The tests were conducted with precision of 0.1 mg. The volumetric shrinkage was measured by hydrostatic weighing before and after polymerization and calculated by known mathematical equations. One-way ANOVA (á=0.05) was used to determine statistically significant differences in volumetric shrinkage among the tested composite resins. Suprafill (1.87±0.01) and Definite (1.89±0.01) shrank significantly less than the other composite resins. SureFil (2.01±0.06), Filtek Z250 (1.99±0.03), and Fill Magic (2.02±0.02) presented intermediate levels of polymerization shrinkage. Alert and Solitaire presented the highest degree of polymerization shrinkage. Knowing the polymerization shrinkage rates of the commercially available composite resins, the dentist would be able to choose between using composite resins with lower polymerization shrinkage rates or adopting technical or operational procedures to minimize the adverse effects deriving from resin contraction during light-activation. PMID:19089177

  3. 3D volumetric radar using 94-GHz millimeter waves

    NASA Astrophysics Data System (ADS)

    Takács, Barnabás

    2006-05-01

    This article describes a novel approach to the real-time visualization of 3D imagery obtained from a 3D millimeter wave scanning radar. The MMW radar system employs a spinning antenna to generate a fan-shaped scanning pattern of the entire scene. The beams formed this way provide all weather 3D distance measurements (range/azimuth display) of objects as they appear on the ground. The beam width of the antenna and its side lobes are optimized to produce the best possible resolution even at distances of up to 15 Kms. To create a full 3D data set the fan-pattern is tilted up and down with the help of a controlled stepper motor. For our experiments we collected data at 0.1 degrees increments while using both bi-static as well as a mono-static antennas in our arrangement. The data collected formed a stack of range-azimuth images in the shape of a cone. This information is displayed using our high-end 3D visualization engine capable of displaying high-resolution volumetric models with 30 frames per second. The resulting 3D scenes can then be viewed from any angle and subsequently processed to integrate, fuse or match them against real-life sensor imagery or 3D model data stored in a synthetic database.

  4. Volumetric Near-Field Microwave Plasma Generation

    NASA Technical Reports Server (NTRS)

    Exton, R. J.; Balla, R. Jeffrey; Herring, G. C.; Popovic, S.; Vuskovic, L.

    2003-01-01

    A periodic series of microwave-induced plasmoids is generated using the outgoing wave from a microwave horn and the reflected wave from a nearby on-axis concave reflector. The plasmoids are spaced at half-wavelength separations according to a standing-wave pattern. The plasmoids are enhanced by an effective focusing in the near field of the horn (Fresnel region) as a result of a diffractive narrowing. Optical imaging, electron density, and rotational temperature measurements characterize the near field plasma region. Volumetric microwave discharges may have application to combustion ignition in scramjet engines.

  5. Performance of the Volumetric Diffusive Respirator at Altitude

    DTIC Science & Technology

    2014-08-18

    AFRL-SA-WP-SR-2014-0020 Performance of the Volumetric Diffusive Respirator at Altitude Dario Rodriquez, MSc1; Tyler Britton, RRT2...the Volumetric Diffusive Respirator at Altitude 5a. CONTRACT NUMBER FA8650-12-2-6B012 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...volumetric diffusive respirator is a pneumatic ventilator used by the U.S. Army Burn Team and the U.S. Air Force Lung Team for patients with hypoxemic

  6. Volumetric Measurements of Amnioserosa Cells in Developing Drosophila

    NASA Astrophysics Data System (ADS)

    Mashburn, David; Jayasinghe, Aroshan; Hutson, Shane

    2013-03-01

    The behavior of cells in tissue in developing Drosophila melanogaster has become increasingly clearer over the past few decades, in large part due to advances in imaging techniques, genetic markers, predictive modeling, and micromanipulation (notably laser microsurgery). We now know apical contractions in amnioserosa cells are a significant factor in large scale processes like germ band retraction and dorsal closure. Also, laser microsurgery induces cellular recoil that strongly mimics a 2D elastic sheet. Still, what we know about these processes comes entirely from the apical surface where the standard fluorescent markers like cadherin are located, but many open questions exist concerning the remaining ``dark'' portion of cells. Does cell volume remain constant during contraction or do cells leak? Also, what shape changes do cells undergo? Do they bulge, wedge, contract prismatically, or something else? By using a marker that labels the entire membrane of amnioserosa cells (Resille, 117) and adapting our watershed segmentation routines for 4D datasets, we have been able to quantify the entire volumetric region of cells in tissue through time and compare changes in apical area and volume. Preliminary results suggest a fairly constant volume over the course of a contraction cycle.

  7. BOREAS HYD-1 Volumetric Soil Moisture Data

    NASA Technical Reports Server (NTRS)

    Cuenca, Richard H.; Kelly, Shaun F.; Stangel, David E.; Hall, Forrest G. (Editor); Knapp, David E. (Editor); Smith, David E. (Technical Monitor)

    2000-01-01

    The Boreal Ecosystem-Atmosphere Study (BOREAS) Hydrology (HYD)-1 team made measurements of volumetric soil moisture at the Southern Study Area (SSA) and Northern Study Area (NSA) tower flux sites in 1994 and at selected tower flux sites in 1995-97. Different methods were used to collect these measurements, including neutron probe and manual and automated Time Domain Reflectometry (TDR). In 1994, the measurements were made every other day at the NSA-OJP (Old Jack Pine), NSA-YJP (Young Jack Pine), NSA-OBS (Old Black Spruce), NSA-Fen, SSA-OJP, SSA-YJP, SSA-Fen, SSA-YA (Young Aspen), and SSA-OBS sites. In 1995-97, when automated equipment was deployed at NSA-OJP, NSA-YJP, NSA-OBS, SSA-OBS, and SSA-OA (Old Aspen), the measurements were made as often as every hour. The data are stored in tabular ASCII files. The volumetric soil moisture data are available from the Earth Observing System Data and Information System (EOSDIS) Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC). The data files are available on a CD-ROM (see document number 20010000884).

  8. Volumetric display with holographic multi-photon excitations

    NASA Astrophysics Data System (ADS)

    Hayasaki, Yoshio; Kumagai, Kota

    2016-10-01

    We developed a volumetric display with holographic two- and multi-photon excitations using a computer-generated hologram displayed on a liquid crystal spatial light modulator. The holographic technique has advantages of increasing the number of voxels of the volumetric graphics per unit time, increasing the total input energy to the volumetric display because the maximum energy incident at a point in the display material is limited by the damage threshold, and controlling the size, shape and spatial position of voxels. We demonstrated a volumetric display with stacked multi-color fluorescence plates.

  9. Widespread Volumetric Brain Changes following Tooth Loss in Female Mice

    PubMed Central

    Avivi-Arber, Limor; Seltzer, Ze'ev; Friedel, Miriam; Lerch, Jason P.; Moayedi, Massieh; Davis, Karen D.; Sessle, Barry J.

    2017-01-01

    Tooth loss is associated with altered sensory, motor, cognitive and emotional functions. These changes vary highly in the population and are accompanied by structural and functional changes in brain regions mediating these functions. It is unclear to what extent this variability in behavior and function is caused by genetic and/or environmental determinants and which brain regions undergo structural plasticity that mediates these changes. Thus, the overall goal of our research program is to identify genetic variants that control structural and functional plasticity following tooth loss. As a step toward this goal, here our aim was to determine whether structural magnetic resonance imaging (sMRI) is sensitive to detect quantifiable volumetric differences in the brains of mice of different genetic background receiving tooth extraction or sham operation. We used 67 adult female mice of 7 strains, comprising the A/J (A) and C57BL/6J (B) strains and a randomly selected sample of 5 of the 23 AXB-BXA strains (AXB1, AXB4, AXB24, BXA14, BXA24) that were produced from the A and B parental mice by recombinations and inbreeding. This panel of 25 inbred strains of genetically diverse inbred strains of mice is used for mapping chromosomal intervals throughout the genome that harbor candidate genes controlling the phenotypic variance of any trait under study. Under general anesthesia, 39 mice received extraction of 3 right maxillary molar teeth and 28 mice received sham operation. On post-extraction day 21, post-mortem whole-brain high-resolution sMRI was used to quantify the volume of 160 brain regions. Compared to sham operation, tooth extraction was associated with a significantly reduced regional and voxel-wise volumes of cortical brain regions involved in processing somatosensory, motor, cognitive and emotional functions, and increased volumes in subcortical sensorimotor and temporal limbic forebrain regions including the amygdala. Additionally, comparison of the 10 BXA14

  10. Widespread Volumetric Brain Changes following Tooth Loss in Female Mice.

    PubMed

    Avivi-Arber, Limor; Seltzer, Ze'ev; Friedel, Miriam; Lerch, Jason P; Moayedi, Massieh; Davis, Karen D; Sessle, Barry J

    2016-01-01

    Tooth loss is associated with altered sensory, motor, cognitive and emotional functions. These changes vary highly in the population and are accompanied by structural and functional changes in brain regions mediating these functions. It is unclear to what extent this variability in behavior and function is caused by genetic and/or environmental determinants and which brain regions undergo structural plasticity that mediates these changes. Thus, the overall goal of our research program is to identify genetic variants that control structural and functional plasticity following tooth loss. As a step toward this goal, here our aim was to determine whether structural magnetic resonance imaging (sMRI) is sensitive to detect quantifiable volumetric differences in the brains of mice of different genetic background receiving tooth extraction or sham operation. We used 67 adult female mice of 7 strains, comprising the A/J (A) and C57BL/6J (B) strains and a randomly selected sample of 5 of the 23 AXB-BXA strains (AXB1, AXB4, AXB24, BXA14, BXA24) that were produced from the A and B parental mice by recombinations and inbreeding. This panel of 25 inbred strains of genetically diverse inbred strains of mice is used for mapping chromosomal intervals throughout the genome that harbor candidate genes controlling the phenotypic variance of any trait under study. Under general anesthesia, 39 mice received extraction of 3 right maxillary molar teeth and 28 mice received sham operation. On post-extraction day 21, post-mortem whole-brain high-resolution sMRI was used to quantify the volume of 160 brain regions. Compared to sham operation, tooth extraction was associated with a significantly reduced regional and voxel-wise volumes of cortical brain regions involved in processing somatosensory, motor, cognitive and emotional functions, and increased volumes in subcortical sensorimotor and temporal limbic forebrain regions including the amygdala. Additionally, comparison of the 10 BXA14

  11. GPU-based Scalable Volumetric Reconstruction for Multi-view Stereo

    SciTech Connect

    Kim, H; Duchaineau, M; Max, N

    2011-09-21

    We present a new scalable volumetric reconstruction algorithm for multi-view stereo using a graphics processing unit (GPU). It is an effectively parallelized GPU algorithm that simultaneously uses a large number of GPU threads, each of which performs voxel carving, in order to integrate depth maps with images from multiple views. Each depth map, triangulated from pair-wise semi-dense correspondences, represents a view-dependent surface of the scene. This algorithm also provides scalability for large-scale scene reconstruction in a high resolution voxel grid by utilizing streaming and parallel computation. The output is a photo-realistic 3D scene model in a volumetric or point-based representation. We demonstrate the effectiveness and the speed of our algorithm with a synthetic scene and real urban/outdoor scenes. Our method can also be integrated with existing multi-view stereo algorithms such as PMVS2 to fill holes or gaps in textureless regions.

  12. Selective-plane illumination microscopy for high-content volumetric biological imaging

    NASA Astrophysics Data System (ADS)

    McGorty, Ryan; Huang, Bo

    2016-03-01

    Light-sheet microscopy, also named selective-plane illumination microscopy, enables optical sectioning with minimal light delivered to the sample. Therefore, it allows one to gather volumetric datasets of developing embryos and other light-sensitive samples over extended times. We have configured a light-sheet microscope that, unlike most previous designs, can image samples in formats compatible with high-content imaging. Our microscope can be used with multi-well plates or with microfluidic devices. In designing our optical system to accommodate these types of sample holders we encounter large optical aberrations. We counter these aberrations with both static optical components in the imaging path and with adaptive optics. Potential applications of this microscope include studying the development of a large number of embryos in parallel and over long times with subcellular resolution and doing high-throughput screens on organisms or cells where volumetric data is necessary.

  13. In vivo volumetric fluorescence sectioning microscopy with mechanical-scan-free hybrid illumination imaging

    PubMed Central

    Lin, Chen-Yen; Lin, Wei-Hsin; Chien, Ju-Hsuan; Tsai, Jui-Chang; Luo, Yuan

    2016-01-01

    Optical sectioning microscopy in wide-field fashion has been widely used to obtain three-dimensional images of biological samples; however, it requires scanning in depth and considerable time to acquire multiple depth information of a volumetric sample. In this paper, in vivo optical sectioning microscopy with volumetric hybrid illumination, with no mechanical moving parts, is presented. The proposed system is configured such that the optical sectioning is provided by hybrid illumination using a digital micro-mirror device (DMD) for uniform and non-uniform pattern projection, while the depth of imaging planes is varied by using an electrically tunable-focus lens with invariant magnification and resolution. We present and characterize the design, implementation, and experimentally demonstrate the proposed system’s ability through 3D imaging of in vivo Canenorhabditis elegans’ growth cones. PMID:27867708

  14. Volumetric Properties of Lithium-Lead Melts

    NASA Astrophysics Data System (ADS)

    Khairulin, R. A.; Abdullaev, R. N.; Stankus, S. V.; Agazhanov, A. S.; Savchenko, I. V.

    2017-02-01

    The density of liquid lithium and lithium-lead alloys (10.02 at.% Pb, 14.98 at.% Pb, 18.06 at.% Pb, 20.02 at.% Pb, 22.24 at.% Pb, 23.09 at.% Pb, 25.10 at.% Pb, 30.15 at.% Pb, 38.21 at.% Pb, 40.11 at.% Pb, 43.08 at.% Pb, 46.65 at.% Pb, 50.15 at.% Pb, 60.23 at.% Pb, 70.01 at.% Pb, 83.00 at.% Pb, and 84.30 at.% Pb) has been measured using the gamma-ray attenuation technique over the temperature range from the liquidus line to 1050 K. The position of the liquidus curve in the Li-Pb phase diagram has been clarified. The compositional dependencies of molar volume and volumetric thermal expansion coefficient of the Li-Pb liquid system have been constructed and discussed.

  15. Automatic coregistration of volumetric images based on implanted fiducial markers.

    PubMed

    Koch, Martin; Maltz, Jonathan S; Belongie, Serge J; Gangadharan, Bijumon; Bose, Supratik; Shukla, Himanshu; Bani-Hashemi, Ali R

    2008-10-01

    The accurate delivery of external beam radiation therapy is often facilitated through the implantation of radio-opaque fiducial markers (gold seeds). Before the delivery of each treatment fraction, seed positions can be determined via low dose volumetric imaging. By registering these seed locations with the corresponding locations in the previously acquired treatment planning computed tomographic (CT) scan, it is possible to adjust the patient position so that seed displacement is accommodated. The authors present an unsupervised automatic algorithm that identifies seeds in both planning and pretreatment images and subsequently determines a rigid geometric transformation between the two sets. The algorithm is applied to the imaging series of ten prostate cancer patients. Each test series is comprised of a single multislice planning CT and multiple megavoltage conebeam (MVCB) images. Each MVCB dataset is obtained immediately prior to a subsequent treatment session. Seed locations were determined to within 1 mm with an accuracy of 97 +/- 6.1% for datasets obtained by application of a mean imaging dose of 3.5 cGy per study. False positives occurred in three separate instances, but only when datasets were obtained at imaging doses too low to enable fiducial resolution by a human operator, or when the prostate gland had undergone large displacement or significant deformation. The registration procedure requires under nine seconds of computation time on a typical contemporary computer workstation.

  16. Cortical thickness and brain volumetric analysis in body dysmorphic disorder

    PubMed Central

    Madsen, Sarah K.; Zai, Alex; Pirnia, Tara; Arienzo, Donatello; Zhan, Liang; Moody, Teena D.; Thompson, Paul M.; Feusner, Jamie D.

    2015-01-01

    Individuals with body dysmorphic disorder (BDD) suffer from preoccupations with perceived defects in physical appearance, causing severe distress and disability. Although BDD affects 1-2% of the population, the neurobiology is not understood. Discrepant results in previous volumetric studies may be due to small sample sizes, and no study has investigated cortical thickness in BDD. The current study is the largest neuroimaging analysis of BDD. Participants included 49 medication-free, right-handed individuals with DSM-IV BDD and 44 healthy controls matched by age, sex, and education. Using high-resolution T1-weighted magnetic resonance imaging, we computed vertex-wise gray matter (GM) thickness on the cortical surface and GM volume using voxel-based morphometry. We also computed volumes in cortical and subcortical regions of interest. In addition to group comparisons, we investigated associations with symptom severity, insight, and anxiety within the BDD group. In BDD, greater anxiety was significantly associated with thinner GM in the left superior temporal cortex and greater GM volume in the right caudate nucleus. There were no significant differences in cortical thickness, GM volume, or volumes in regions of interest between BDD and control subjects. Subtle associations with clinical symptoms may characterize brain morphometric patterns in BDD, rather than large group differences in brain structure. PMID:25797401

  17. A volumetric flow sensor for automotive injection systems

    NASA Astrophysics Data System (ADS)

    Schmid, U.; Krötz, G.; Schmitt-Landsiedel, D.

    2008-04-01

    For further optimization of the automotive power train of diesel engines, advanced combustion processes require a highly flexible injection system, provided e.g. by the common rail (CR) injection technique. In the past, the feasibility to implement injection nozzle volumetric flow sensors based on the thermo-resistive measurement principle has been demonstrated up to injection pressures of 135 MPa (1350 bar). To evaluate the transient behaviour of the system-integrated flow sensors as well as an injection amount indicator used as a reference method, hydraulic simulations on the system level are performed for a CR injection system. Experimentally determined injection timings were found to be in good agreement with calculated values, especially for the novel sensing element which is directly implemented into the hydraulic system. For the first time pressure oscillations occurring after termination of the injection pulse, predicted theoretically, could be verified directly in the nozzle. In addition, the injected amount of fuel is monitored with the highest resolution ever reported in the literature.

  18. Normative biometrics for fetal ocular growth using volumetric MRI reconstruction.

    PubMed

    Velasco-Annis, Clemente; Gholipour, Ali; Afacan, Onur; Prabhu, Sanjay P; Estroff, Judy A; Warfield, Simon K

    2015-04-01

    To determine normative ranges for fetal ocular biometrics between 19 and 38 weeks gestational age (GA) using volumetric MRI reconstruction. The 3D images of 114 healthy fetuses between 19 and 38 weeks GA were created using super-resolution volume reconstructions from MRI slice acquisitions. These 3D images were semi-automatically segmented to measure fetal orbit volume, binocular distance (BOD), interocular distance (IOD), and ocular diameter (OD). All biometry correlated with GA (Volume, Pearson's correlation coefficient (CC) = 0.9680; BOD, CC = 0.9552; OD, CC = 0.9445; and IOD, CC = 0.8429), and growth curves were plotted against linear and quadratic growth models. Regression analysis showed quadratic models to best fit BOD, IOD, and OD and a linear model to best fit volume. Orbital volume had the greatest correlation with GA, although BOD and OD also showed strong correlation. The normative data found in this study may be helpful for the detection of congenital fetal anomalies with more consistent measurements than are currently available. © 2015 John Wiley & Sons, Ltd. © 2015 John Wiley & Sons, Ltd.

  19. Volumetric Modulated Arc Therapy (VMAT) Treatment Planning for Superficial Tumors

    SciTech Connect

    Zacarias, Albert S.; Brown, Mellonie F.; Mills, Michael D.

    2010-10-01

    The physician's planning objective is often a uniform dose distribution throughout the planning target volume (PTV), including superficial PTVs on or near the surface of a patient's body. Varian's Eclipse treatment planning system uses a progressive resolution optimizer (PRO), version 8.2.23, for RapidArc dynamic multileaf collimator volumetric modulated arc therapy planning. Because the PRO is a fast optimizer, optimization convergence errors (OCEs) produce dose nonuniformity in the superficial area of the PTV. We present a postsurgical cranial case demonstrating the recursive method our clinic uses to produce RapidArc treatment plans. The initial RapidArc treatment plan generated using one 360{sup o} arc resulted in substantial dose nonuniformity in the superficial section of the PTV. We demonstrate the use of multiple arcs to produce improved dose uniformity in this region. We also compare the results of this superficial dose compensation method to the results of a recursive method of dose correction that we developed in-house to correct optimization convergence errors in static intensity-modulated radiation therapy treatment plans. The results show that up to 4 arcs may be necessary to provide uniform dose to the surface of the PTV with the current version of the PRO.

  20. Volumetric Real-Time Imaging Using a CMUT Ring Array

    PubMed Central

    Choe, Jung Woo; Oralkan, Ömer; Nikoozadeh, Amin; Gencel, Mustafa; Stephens, Douglas N.; O’Donnell, Matthew; Sahn, David J.; Khuri-Yakub, Butrus T.

    2012-01-01

    A ring array provides a very suitable geometry for forward-looking volumetric intracardiac and intravascular ultrasound imaging. We fabricated an annular 64-element capacitive micromachined ultrasonic transducer (CMUT) array featuring a 10-MHz operating frequency and a 1.27-mm outer radius. A custom software suite was developed to run on a PC-based imaging system for real-time imaging using this device. This paper presents simulated and experimental imaging results for the described CMUT ring array. Three different imaging methods—flash, classic phased array (CPA), and synthetic phased array (SPA)—were used in the study. For SPA imaging, two techniques to improve the image quality—Hadamard coding and aperture weighting—were also applied. The results show that SPA with Hadamard coding and aperture weighting is a good option for ring-array imaging. Compared with CPA, it achieves better image resolution and comparable signal-to-noise ratio at a much faster image acquisition rate. Using this method, a fast frame rate of up to 463 volumes per second is achievable if limited only by the ultrasound time of flight; with the described system we reconstructed three cross-sectional images in real-time at 10 frames per second, which was limited by the computation time in synthetic beamforming. PMID:22718870

  1. Cortical thickness and brain volumetric analysis in body dysmorphic disorder.

    PubMed

    Madsen, Sarah K; Zai, Alex; Pirnia, Tara; Arienzo, Donatello; Zhan, Liang; Moody, Teena D; Thompson, Paul M; Feusner, Jamie D

    2015-04-30

    Individuals with body dysmorphic disorder (BDD) suffer from preoccupations with perceived defects in physical appearance, causing severe distress and disability. Although BDD affects 1-2% of the population, the neurobiology is not understood. Discrepant results in previous volumetric studies may be due to small sample sizes, and no study has investigated cortical thickness in BDD. The current study is the largest neuroimaging analysis of BDD. Participants included 49 medication-free, right-handed individuals with DSM-IV BDD and 44 healthy controls matched by age, sex, and education. Using high-resolution T1-weighted magnetic resonance imaging, we computed vertex-wise gray matter (GM) thickness on the cortical surface and GM volume using voxel-based morphometry. We also computed volumes in cortical and subcortical regions of interest. In addition to group comparisons, we investigated associations with symptom severity, insight, and anxiety within the BDD group. In BDD, greater anxiety was significantly associated with thinner GM in the left superior temporal cortex and greater GM volume in the right caudate nucleus. There were no significant differences in cortical thickness, GM volume, or volumes in regions of interest between BDD and control subjects. Subtle associations with clinical symptoms may characterize brain morphometric patterns in BDD, rather than large group differences in brain structure. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  2. Volumetric accuracy of cone-beam computed tomography.

    PubMed

    Park, Cheol-Woo; Kim, Jin-Ho; Seo, Yu-Kyeong; Lee, Sae-Rom; Kang, Ju-Hee; Oh, Song-Hee; Kim, Gyu-Tae; Choi, Yong-Suk; Hwang, Eui-Hwan

    2017-09-01

    This study was performed to investigate the influence of object shape and distance from the center of the image on the volumetric accuracy of cone-beam computed tomography (CBCT) scans, according to different parameters of tube voltage and current. Four geometric objects (cylinder, cube, pyramid, and hexagon) with predefined dimensions were fabricated. The objects consisted of Teflon-perfluoroalkoxy embedded in a hydrocolloid matrix (Dupli-Coe-Loid TM; GC America Inc., Alsip, IL, USA), encased in an acrylic resin cylinder assembly. An Alphard Vega Dental CT system (Asahi Roentgen Ind. Co., Ltd, Kyoto, Japan) was used to acquire CBCT images. OnDemand 3D (CyberMed Inc., Seoul, Korea) software was used for object segmentation and image analysis. The accuracy was expressed by the volume error (VE). The VE was calculated under 3 different exposure settings. The measured volumes of the objects were compared to the true volumes for statistical analysis. The mean VE ranged from -4.47% to 2.35%. There was no significant relationship between an object's shape and the VE. A significant correlation was found between the distance of the object to the center of the image and the VE. Tube voltage affected the volume measurements and the VE, but tube current did not. The evaluated CBCT device provided satisfactory volume measurements. To assess volume measurements, it might be sufficient to use serial scans with a high resolution, but a low dose. This information may provide useful guidance for assessing volume measurements.

  3. Volumetric Analysis of Regional Cerebral Development in Preterm Children

    PubMed Central

    Kesler, Shelli R.; Ment, Laura R.; Vohr, Betty; Pajot, Sarah K.; Schneider, Karen C.; Katz, Karol H.; Ebbitt, Timothy B.; Duncan, Charles C.; Makuch, Robert W.; Reiss, Allan L.

    2011-01-01

    Preterm birth is frequently associated with both neuropathologic and cognitive sequelae. This study examined cortical lobe, subcortical, and lateral ventricle development in association with perinatal variables and cognitive outcome. High-resolution volumetric magnetic resonance imaging scans were acquired and quantified using advanced image processing techniques. Seventy-three preterm and 33 term control children ages 7.3-11.4 years were included in the study. Results indicated disproportionately enlarged parietal and frontal gray matter, occipital horn, and ventricular body, as well as reduced temporal and subcortical gray volumes in preterm children compared with control subjects. Birth weight was negatively correlated with parietal and frontal gray, as well as occipital horn volumes. Intraventricular hemorrhage was associated with reduced subcortical gray matter. Ventricular cerebrospinal fluid was negatively correlated with subcortical gray matter volumes but not with white matter volumes. Maternal education was the strongest predictor of cognitive function in the preterm group. Preterm birth appears to be associated with disorganized cortical development, possibly involving disrupted synaptic pruning and neural migration. Lower birth weight and the presence of intraventricular hemorrhage may increase the risk for neuroanatomic abnormality. PMID:15519112

  4. A Trimodality Comparison of Volumetric Bone Imaging Technologies. Part III: SD, SEE, LSC Association With Fragility Fractures

    PubMed Central

    Wong, Andy K. O.; Beattie, Karen A.; Min, Kevin K. H.; Merali, Zamir; Webber, Colin E.; Gordon, Christopher L.; Papaioannou, Alexandra; Cheung, Angela M. W.; Adachi, Jonathan D.

    2016-01-01

    Part II of this 3-part series demonstrated 1-yr precision, standard error of the estimate, and 1-yr least significant change for volumetric bone outcomes determined using peripheral (p) quantitative computed tomography (QCT) and peripheral magnetic resonance imaging (pMRI) modalities in vivo. However, no clinically relevant outcomes have been linked to these measures of change. This study examined 97 women with mean age of 75 ± 9 yr and body mass index of 26.84 ± 4.77 kg/m2, demonstrating a lack of association between fragility fractures and standard deviation, least significant change and standard error of the estimate-based unit differences in volumetric bone outcomes derived from both pMRI and pQCT. Only cortical volumetric bone mineral density and cortical thickness derived from high-resolution pQCT images were associated with an increased odds for fractures. The same measures obtained by pQCT erred toward significance. Despite the smaller 1-yr and short-term precision error for measures at the tibia vs the radius, the associations with fractures observed at the radius were larger than at the tibia for high-resolution pQCT. Unit differences in cortical thickness and cortical volumetric bone mineral density able to yield a 50% increase in odds for fractures were quantified here and suggested as a reference for future power computations. PMID:25129407

  5. Volumetric breast density evaluation from ultrasound tomography images

    SciTech Connect

    Glide-Hurst, Carri K.; Duric, Neb; Littrup, Peter

    2008-09-15

    Previous ultrasound tomography work conducted by our group showed a direct correlation between measured sound speed and physical density in vitro, and increased in vivo sound speed with increasing mammographic density, a known risk factor for breast cancer. Building on these empirical results, the purpose of this work was to explore a metric to quantify breast density using our ultrasound tomography sound speed images in a manner analogous to computer-assisted mammogram segmentation for breast density analysis. Therefore, volumetric ultrasound percent density (USPD) is determined by segmenting high sound speed areas from each tomogram using a k-means clustering routine, integrating these results over the entire volume of the breast, and dividing by whole-breast volume. First, a breast phantom comprised of fat inclusions embedded in fibroglandular tissue was scanned four times with both our ultrasound tomography clinical prototype (with 4 mm spatial resolution) and CT. The coronal transmission tomograms and CT images were analyzed using semiautomatic segmentation routines, and the integrated areas of the phantom's fat inclusions were compared between the four repeated scans. The average variability for inclusion segmentation was {approx}7% and {approx}2%, respectively, and a close correlation was observed in the integrated areas between the two modalities. Next, a cohort of 93 patients was imaged, yielding volumetric coverage of the breast (45-75 sound speed tomograms/patient). The association of USPD with mammographic percent density (MPD) was evaluated using two measures: (1) qualitative, as determined by a radiologist's visual assessment using BI-RADS Criteria and (2) quantitative, via digitization and semiautomatic segmentation of craniocaudal and mediolateral oblique mammograms. A strong positive association between BI-RADS category and USPD was demonstrated [Spearman {rho}=0.69 (p<0.001)], with significant differences between all BI-RADS categories as assessed

  6. Quantification of volumetric cerebral blood flow using hybrid laser speckle contract and optical coherence tomography (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Valim, Niksa; Dunn, Andrew K.

    2016-03-01

    Studying neurovascular blood flow function in cerebrovascular activities requires accurate visualization and characterization of blood flow volume as well as the dynamics of blood cells in microcirculation. In this study, we present a novel integration of laser speckle contrast imaging (LSCI) and spectral domain optical coherence tomography (SD-OCT) for rapid volumetric imaging of blood flow in cortical capillaries. LSCI uses the illumination of wide-field near infrared light (NIR) and monitors back scattered light to characterize the relative dynamics of blood flow in microcirculation. Absolute measurement of blood cells and blood volume requires high-resolution volumetric structural information. SD-OCT system uses coherence gating to measure scattered light from a small volume within high structural resolution. The structural imaging system rapidly assesses large number of capillaries for spatio-temporal tracking of red blood cells (RBC). A very fast-ultra resolution SD-OCT system was developed for imaging high-resolution volumetric samples. The system employed an ultra wideband light source (1310 ± 200 nm in wavelength) corresponding to an axial resolution of 3 micrometers in tissue. The spectrometer of the SD-OCT was customized for a maximum scanning rate of 147,000 line/s. We demonstrated a fast volumetric OCT angiography algorithm to visualize large numbers of vessels in a 2-mm deep sample volume. A LSCI system that has been developed previously in our group was integrated to the imaging system for the characterization of dynamic blood cells. The conjunction data from LSCI and SD-OCT systems imply the feasibility of accurate quantification of absolute cortical blood flow.

  7. Bulk volumetric liquid water content in a seasonal snowpack: modeling its dynamics in different climatic conditions

    NASA Astrophysics Data System (ADS)

    Avanzi, Francesco; Yamaguchi, Satoru; Hirashima, Hiroyuki; De Michele, Carlo

    2015-12-01

    We focus on the dynamics of volumetric liquid water content in seasonal snow covers. This is a key variable describing the fate of snowpacks during the melting season. However, its measurement and/or prediction by means of models at high spatial and temporal resolutions is still difficult due to both practical and theoretical reasons. To overcome these limitations in operational applications, we test the capability of a one-dimensional model to predict the dynamics of bulk volumetric liquid water content during a snow season. Multi-year data collected in three experimental sites in Japan are used as an evaluation. These sites are subjected to different climatic conditions. The model requires the calibration of one or two parameters, according to the degree of detail used. Either a simple temperature-index or a coupled melt-freeze temperature-index approach are considered to predict melting and/or melt-freeze dynamics of liquid water. Results show that, if melt-freeze dynamics are modeled, median absolute differences between data and predictions are consistently lower than 1 vol% at the sites where data of liquid water content are available. In addition, we find also that the model predicts correctly a dry condition in 80% of the observed cases at a site where calibration data are scarce. At the same site, observed isothermal conditions of the snow cover at 0 °C correspond to predictions of bulk volumetric liquid water content that are greater than 0.

  8. A new contrast-assisted method in microcirculation volumetric flow assessment

    NASA Astrophysics Data System (ADS)

    Lu, Sheng-Yi; Chen, Yung-Sheng; Yeh, Chih-Kuang

    2007-03-01

    Microcirculation volumetric flow rate is a significant index in diseases diagnosis and treatment such as diabetes and cancer. In this study, we propose an integrated algorithm to assess microcirculation volumetric flow rate including estimation of blood perfused area and corresponding flow velocity maps based on high frequency destruction/contrast replenishment imaging technique. The perfused area indicates the blood flow regions including capillaries, arterioles and venules. Due to the echo variance changes between ultrasonic contrast agents (UCAs) pre- and post-destruction two images, the perfused area can be estimated by the correlation-based approach. The flow velocity distribution within the perfused area can be estimated by refilling time-intensity curves (TICs) after UCAs destruction. Most studies introduced the rising exponential model proposed by Wei (1998) to fit the TICs. Nevertheless, we found the TICs profile has a great resemblance to sigmoid function in simulations and in vitro experiments results. Good fitting correlation reveals that sigmoid model was more close to actual fact in describing destruction/contrast replenishment phenomenon. We derived that the saddle point of sigmoid model is proportional to blood flow velocity. A strong linear relationship (R = 0.97) between the actual flow velocities (0.4-2.1 mm/s) and the estimated saddle constants was found in M-mode and B-mode flow phantom experiments. Potential applications of this technique include high-resolution volumetric flow rate assessment in small animal tumor and the evaluation of superficial vasculature in clinical studies.

  9. Event-related Single-shot Volumetric Functional Magnetic Resonance Inverse Imaging of Visual Processing

    PubMed Central

    Lin, Fa-Hsuan; Witzel, Thomas; Mandeville, Joseph B.; Polimeni, Jonathan R.; Zeffiro, Thomas A.; Greve, Douglas N.; Wiggins, Graham; Wald, Lawrence L.; Belliveau, John W.

    2008-01-01

    Developments in multi-channel radio-frequency (RF) coil array technology have enabled functional magnetic resonance imaging (fMRI) with higher degrees of spatial and temporal resolution. While modest improvement in temporal acceleration has been achieved by increasing the number of RF coils, in parallel data acquisition techniques, the maximum attainable acceleration is intrinsically limited only by the amount of independent spatial information in the combined array channels. Since the geometric configuration of a large-n MRI head coil array is similar to that used in EEG electrode or MEG SQUID sensor arrays, the source localization algorithms used in MEG or EEG source imaging can be extended to also process MRI coil array data, resulting in greatly improved temporal resolution by minimizing k-space traversal during signal acquisition. Using a novel approach, we acquire multi-channel MRI head coil array data and then apply inverse reconstruction methods to obtain volumetric fMRI estimates of blood oxygenation level dependent (BOLD) contrast at unprecedented whole-brain acquisition rates of 100 ms per sample. We call this combination of techniques magnetic resonance Inverse Imaging (InI), a method that provides estimates of dynamic spatially-resolved signal change that can be used to construct statistical maps of task-related brain activity. We demonstrate the sensitivity and inter-subject reliability of volumetric InI using an event-related design to probe the hemodynamic signal modulations in primary visual cortex. Robust results from both single subject and group analyses demonstrate the sensitivity and feasibility of using volumetric InI in high temporal resolution investigations of human brain function. PMID:18538587

  10. Event-related single-shot volumetric functional magnetic resonance inverse imaging of visual processing.

    PubMed

    Lin, Fa-Hsuan; Witzel, Thomas; Mandeville, Joseph B; Polimeni, Jonathan R; Zeffiro, Thomas A; Greve, Douglas N; Wiggins, Graham; Wald, Lawrence L; Belliveau, John W

    2008-08-01

    Developments in multi-channel radio-frequency (RF) coil array technology have enabled functional magnetic resonance imaging (fMRI) with higher degrees of spatial and temporal resolution. While modest improvement in temporal acceleration has been achieved by increasing the number of RF coils, the maximum attainable acceleration in parallel MRI acquisition is intrinsically limited only by the amount of independent spatial information in the combined array channels. Since the geometric configuration of a large-n MRI head coil array is similar to that used in EEG electrode or MEG SQUID sensor arrays, the source localization algorithms used in MEG or EEG source imaging can be extended to also process MRI coil array data, resulting in greatly improved temporal resolution by minimizing k-space traversal during signal acquisition. Using a novel approach, we acquire multi-channel MRI head coil array data and then apply inverse reconstruction methods to obtain volumetric fMRI estimates of blood oxygenation level dependent (BOLD) contrast at unprecedented whole-brain acquisition rates of 100 ms. We call this combination of techniques magnetic resonance Inverse Imaging (InI), a method that provides estimates of dynamic spatially-resolved signal change that can be used to construct statistical maps of task-related brain activity. We demonstrate the sensitivity and inter-subject reliability of volumetric InI using an event-related design to probe the hemodynamic signal modulations in primary visual cortex. Robust results from both single subject and group analyses demonstrate the sensitivity and feasibility of using volumetric InI in high temporal resolution investigations of human brain function.

  11. Imaging multi-scale dynamics in vivo with spiral volumetric optoacoustic tomography

    NASA Astrophysics Data System (ADS)

    Deán-Ben, X. Luís.; Fehm, Thomas F.; Ford, Steven J.; Gottschalk, Sven; Razansky, Daniel

    2017-03-01

    Imaging dynamics in living organisms is essential for the understanding of biological complexity. While multiple imaging modalities are often required to cover both microscopic and macroscopic spatial scales, dynamic phenomena may also extend over different temporal scales, necessitating the use of different imaging technologies based on the trade-off between temporal resolution and effective field of view. Optoacoustic (photoacoustic) imaging has been shown to offer the exclusive capability to link multiple spatial scales ranging from organelles to entire organs of small animals. Yet, efficient visualization of multi-scale dynamics remained difficult with state-of-the-art systems due to inefficient trade-offs between image acquisition and effective field of view. Herein, we introduce a spiral volumetric optoacoustic tomography (SVOT) technique that provides spectrally-enriched high-resolution optical absorption contrast across multiple spatio-temporal scales. We demonstrate that SVOT can be used to monitor various in vivo dynamics, from video-rate volumetric visualization of cardiac-associated motion in whole organs to high-resolution imaging of pharmacokinetics in larger regions. The multi-scale dynamic imaging capability thus emerges as a powerful and unique feature of the optoacoustic technology that adds to the multiple advantages of this technology for structural, functional and molecular imaging.

  12. Dual Frequency Band Annular Probe for Volumetric Pulse-echo Optoacoustic Imaging

    NASA Astrophysics Data System (ADS)

    Kalkhoran, Mohammad Azizian; Varray, François; Vray, Didier

    Optoacoustic (OA) pulse echo (PE) imaging is a hybridized modality that is capable of providing physiological information on the basis of anatomical structure. In this work, we propose a dual frequency band annular probe for backward mode volumetric PE/OA imaging. The performance of this design is evaluated based on the spatio-temporal impulse response, three dimensional steerability of the transducer and point spread function. Optimum settings for number of elements in each ring and maximum steering are suggested. The transducer design and synthetic array beamforming simulation are presented. The resolution performance and reconstruction capabilities are shown with the in-silico measurements.

  13. Volumetric structured illumination microscopy enabled by a tunable-focus lens.

    PubMed

    Hinsdale, Taylor; Malik, Bilal H; Olsovsky, Cory; Jo, Javier A; Maitland, Kristen C

    2015-11-01

    We present a mechanical-scan-free method for volumetric imaging of biological tissue. The optical sectioning is provided by structured illumination, and the depth of the imaging plane is varied using an electrically tunable-focus lens. We characterize and evaluate the ability of this axial-scanning mechanism in structured illumination microscopy and demonstrate its ability to perform subcellular resolution imaging in oral mucosa ex vivo. The proposed mechanism can potentially convert any wide-field microscope to a 3D-imaging platform without the need for mechanical scanning of imaging optics and/or sample.

  14. Improved Second-Generation 3-D Volumetric Display System. Revision 2

    DTIC Science & Technology

    1998-10-01

    submarines operate in littoral waters, awareness of the ocean bottom has increased. In the case of the Navy’s new 3-D display, sonar data of the ocean...color for group viewing in the Submarine Attack Center to guide the submarine in shallow waters, live and in real time. In the case of the 3-D Volu...considering the following. In the case of volumetric scanning, a typical volume with a resolution of 1000 voxels on each side would contain (1000)3

  15. Morphological and Volumetric Assessment of Cerebral Ventricular System with 3D Slicer Software.

    PubMed

    Gonzalo Domínguez, Miguel; Hernández, Cristina; Ruisoto, Pablo; Juanes, Juan A; Prats, Alberto; Hernández, Tomás

    2016-06-01

    We present a technological process based on the 3D Slicer software for the three-dimensional study of the brain's ventricular system with teaching purposes. It values the morphology of this complex brain structure, as a whole and in any spatial position, being able to compare it with pathological studies, where its anatomy visibly changes. 3D Slicer was also used to obtain volumetric measurements in order to provide a more comprehensive and detail representation of the ventricular system. We assess the potential this software has for processing high resolution images, taken from Magnetic Resonance and generate the three-dimensional reconstruction of ventricular system.

  16. Volumetric structured illumination microscopy enabled by a tunable-focus lens

    PubMed Central

    Hinsdale, Taylor; Malik, Bilal H.; Olsovsky, Cory; Jo, Javier A.; Maitland, Kristen C.

    2016-01-01

    We present a mechanical-scan-free method for volumetric imaging of biological tissue. The optical sectioning is provided by structured illumination, and the depth of the imaging plane is varied using an electrically tunable-focus lens. We characterize and evaluate the ability of this axial-scanning mechanism in structured illumination microscopy and demonstrate its ability to perform subcellular resolution imaging in oral mucosa ex vivo. The proposed mechanism can potentially convert any wide-field microscope to a 3D-imaging platform without the need for mechanical scanning of imaging optics and/or sample. PMID:26512489

  17. Constrained reverse diffusion for thick slice interpolation of 3D volumetric MRI images.

    PubMed

    Neubert, Aleš; Salvado, Olivier; Acosta, Oscar; Bourgeat, Pierrick; Fripp, Jurgen

    2012-03-01

    Due to physical limitations inherent in magnetic resonance imaging scanners, three dimensional volumetric scans are often acquired with anisotropic voxel resolution. We investigate several interpolation approaches to reduce the anisotropy and present a novel approach - constrained reverse diffusion for thick slice interpolation. This technique was compared to common methods: linear and cubic B-Spline interpolation and a technique based on non-rigid registration of neighboring slices. The methods were evaluated on artificial MR phantoms and real MR scans of human brain. The constrained reverse diffusion approach delivered promising results and provides an alternative for thick slice interpolation, especially for higher anisotropy factors.

  18. Rapidly-steered single-element ultrasound for real-time volumetric imaging and guidance

    NASA Astrophysics Data System (ADS)

    Stauber, Mark; Western, Craig; Solek, Roman; Salisbury, Kenneth; Hristov, Dmitre; Schlosser, Jeffrey

    2016-03-01

    Volumetric ultrasound (US) imaging has the potential to provide real-time anatomical imaging with high soft-tissue contrast in a variety of diagnostic and therapeutic guidance applications. However, existing volumetric US machines utilize "wobbling" linear phased array or matrix phased array transducers which are costly to manufacture and necessitate bulky external processing units. To drastically reduce cost, improve portability, and reduce footprint, we propose a rapidly-steered single-element volumetric US imaging system. In this paper we explore the feasibility of this system with a proof-of-concept single-element volumetric US imaging device. The device uses a multi-directional raster-scan technique to generate a series of two-dimensional (2D) slices that were reconstructed into three-dimensional (3D) volumes. At 15 cm depth, 90° lateral field of view (FOV), and 20° elevation FOV, the device produced 20-slice volumes at a rate of 0.8 Hz. Imaging performance was evaluated using an US phantom. Spatial resolution was 2.0 mm, 4.7 mm, and 5.0 mm in the axial, lateral, and elevational directions at 7.5 cm. Relative motion of phantom targets were automatically tracked within US volumes with a mean error of -0.3+/-0.3 mm, -0.3+/-0.3 mm, and -0.1+/-0.5 mm in the axial, lateral, and elevational directions, respectively. The device exhibited a mean spatial distortion error of 0.3+/-0.9 mm, 0.4+/-0.7 mm, and -0.3+/-1.9 in the axial, lateral, and elevational directions. With a production cost near $1000, the performance characteristics of the proposed system make it an ideal candidate for diagnostic and image-guided therapy applications where form factor and low cost are paramount.

  19. Three-dimensional volumetric analysis and reconstruction of amygdala and hippocampal head, body and tail.

    PubMed

    Malykhin, Nikolai V; Bouchard, Thomas P; Ogilvie, Catherine J; Coupland, Nicholas J; Seres, Peter; Camicioli, Richard

    2007-07-15

    Volumetric changes in the amygdala and hippocampus are relevant to many disorders, but their close proximity makes it difficult to separate these structures by magnetic resonance imaging, leading many volumetric protocols to exclude problematic slices from analysis, or to analyze the amygdalo-hippocampal complex conjointly. The hippocampus tail is also often excluded, because of the difficulty in separating it from the thalamus. We have developed a reliable protocol for volumetric analysis and 3-D reconstruction of the amygdala and hippocampus (as a whole and in its anatomical parts). Twenty volunteers from clinical and healthy populations were recruited. T1-weighted images were acquired at 1.5 Tesla with native spatial resolution of 1.5 mm x 1.0 mm x 1.0 mm. Volumetric analyses were performed blind to diagnosis, using the interactive software package DISPLAY. Inter-rater (intrarater) intraclass correlations for the method were: 0.95 (0.88) for hippocampus tail, 0.83 (0.93) for hippocampus body, 0.95 (0.92) for hippocampus head, 0.96 (0.86) for total hippocampus and 0.86 (0.94) for amygdala. Volumes (mean+/-S.D.) corrected for intracranial volume for this mixed group were for the hippocampal tail: 0.325+/-0.087 cm(3); hippocampal body: 0.662+/-0.120 cm(3); hippocampal head: 1.23+/-0.174 cm(3); total hippocampus: 2.218+/-0.217 cm(3), and amygdala: 0.808+/-0.185 cm(3). In conclusion, the study demonstrates that the amygdala and hippocampal parts can be quantified reliably.

  20. Fast volumetric imaging of ethanol metabolism in rat liver with hyperpolarized [1-13C]-pyruvate

    PubMed Central

    Josan, Sonal; Spielman, Daniel; Yen, Yi-Fen; Hurd, Ralph; Pfefferbaum, Adolf; Mayer, Dirk

    2012-01-01

    Rapid, volumetric imaging of hyperpolarized 13C compounds allows the real time measurement of metabolic activity and can be useful in distinguishing between normal and diseased tissues. This work extends a fast 2D under-sampled spiral magnetic resonance spectroscopic imaging (MRSI) sequence to provide volumetric coverage, acquiring a 16×16×12 matrix with a nominal 5 mm isotropic resolution in 4.5 s. The rapid acquisition enables a high temporal resolution for dynamic imaging. This dynamic 3D MRSI method was used to investigate hyperpolarized [1-13C]-pyruvate metabolism modulated by the administration of ethanol in rat liver. A significant increase in the pyruvate to lactate conversion was observed in the liver due to the greater availability of NADH from ethanol metabolism. PMID:22331837

  1. Regional Volumetric Change of the Tongue during Mastication in Pigs

    PubMed Central

    LIU, Z. J.; YAMAMURA, B.; SHCHERBATYY, V.; GREEN, J. R.

    2007-01-01

    SUMMARY Structure and movement of the tongue have been studied extensively, but little has been done on its 3D deformation and ensuing volumetric changes during various functions. The purpose of this study is to investigate the volumetric changes of a regional section of the tongue during feeding. Four 12-week-old Yucatan miniature pigs were used. During natural mastication and water drinking, the width, length, thickness, and volumetric changes were measured using six implanted ultrasonic crystals, which circumscribed a wedge-shaped volume in the region of the tongue body. Jaw movements were videotaped and digitized. Signals from these two sources were synchronized to allow real-time analyses. Significant volumetric changes (p<0.001) were found in chewing, ingestion and drinking, and these changes were stereotypical in relation to rhythmic jaw movements. Volumetric change during chewing was not only more regular, but significantly larger (45.6%, p < 0.001) than that during ingestion (31.4%). The volumetric changes were less regular in drinking and the changing range (30.4%) was close to that during ingestion. Real-time analysis indicated that the volume began increasing at late jaw closing and reached the peak at late power stroke. The duration of volume increase only took up 33.4% of the total chewing cycle length, significantly shorter than that of volume decrease. Correlation analysis revealed that the change in posterior dorsal and ventral widths had the greatest positive association with volumetric change (r = 0.43) in direction. The covariance calculations further indicated that dimensional changes in length and thickness coupled negatively with volumetric changes in amplitude. These results revealed that regional volumetric change of the tongue occurs during feeding, and chewing requires larger volumetric changes than do ingestion and drinking. Volumetric expansion occurs in the phase of power stroke during chewing and is coupled with increases of widths in

  2. A hand-held immaterial volumetric display

    NASA Astrophysics Data System (ADS)

    Sand, Antti; Rakkolainen, Ismo

    2014-03-01

    We have created an ultralight, movable, "immaterial" fogscreen. It is based on the fogscreen mid-air imaging technology. The hand-held unit is roughly the size and weight of an ordinary toaster. If the screen is tracked, it can be swept in the air to create mid-air slices of volumetric objects, or to show augmented reality (AR) content on top of real objects. Interfacing devices and methodologies, such as hand and gesture trackers, camera-based trackers and object recognition, can make the screen interactive. The user can easily interact with any physical object or virtual information, as the screen is permeable. Any real objects can be seen through the screen, instead of e.g., through a video-based augmented reality screen. It creates a mixed reality setup where both the real world object and the augmented reality content can be viewed and interacted with simultaneously. The hand-held mid-air screen can be used e.g., as a novel collaborating or classroom tool for individual students or small groups.

  3. Hyperspectral image classification based on volumetric texture and dimensionality reduction

    NASA Astrophysics Data System (ADS)

    Su, Hongjun; Sheng, Yehua; Du, Peijun; Chen, Chen; Liu, Kui

    2015-06-01

    A novel approach using volumetric texture and reduced-spectral features is presented for hyperspectral image classification. Using this approach, the volumetric textural features were extracted by volumetric gray-level co-occurrence matrices (VGLCM). The spectral features were extracted by minimum estimated abundance covariance (MEAC) and linear prediction (LP)-based band selection, and a semi-supervised k-means (SKM) clustering method with deleting the worst cluster (SKMd) bandclustering algorithms. Moreover, four feature combination schemes were designed for hyperspectral image classification by using spectral and textural features. It has been proven that the proposed method using VGLCM outperforms the gray-level co-occurrence matrices (GLCM) method, and the experimental results indicate that the combination of spectral information with volumetric textural features leads to an improved classification performance in hyperspectral imagery.

  4. Using Kriging to Interpolate Spatially Distributed Volumetric Medical Data

    DTIC Science & Technology

    1996-12-01

    Routine cases in diagnostic radiology require the interpolation of volumetric medical imaging data sets. Inaccurate renditions of interpolated...patient space. Kriging is investigated in this research to interpolate medical imaging volumes. Kriging requires data to be spatially distributed

  5. Volumetric expansion of gutta-percha in contact with eugenol.

    PubMed

    Michaud, Rick A; Burgess, John; Barfield, Robert D; Cakir, Deniz; McNeal, Sandre F; Eleazer, Paul D

    2008-12-01

    The aim of this study was to compare the volumetric expansion of gutta-percha in the presence of eugenol or physiologic saline over time. Sections of gutta-percha cones were scanned to determine their total volume and surface area. They were then placed in sealed test tubes with either 2 microL eugenol or 2 microL saline and allowed to soak for 24 hours, 7 days, or 30 days. The results were scanned again to determine the volumetric changes in the material after placement in the test solutions. The results were statistically analyzed by using t tests and analysis of variance. Specimens soaked in eugenol showed a dramatic increase in volumetric expansion versus the saline group at all time periods. Sealers that incorporate eugenol could be attributed to gutta-percha volumetric expansion over time, thereby creating a better seal of the obturation material.

  6. Increasing the volumetric efficiency of Diesel engines by intake pipes

    NASA Technical Reports Server (NTRS)

    List, Hans

    1933-01-01

    Development of a method for calculating the volumetric efficiency of piston engines with intake pipes. Application of this method to the scavenging pumps of two-stroke-cycle engines with crankcase scavenging and to four-stroke-cycle engines. The utility of the method is demonstrated by volumetric-efficiency tests of the two-stroke-cycle engines with crankcase scavenging. Its practical application to the calculation of intake pipes is illustrated by example.

  7. Fronto-limbic volumetric changes in major depressive disorder.

    PubMed

    Malykhin, Nikolai V; Carter, Rawle; Hegadoren, Kathleen M; Seres, Peter; Coupland, Nicholas J

    2012-02-01

    Fronto-limbic dysregulation in major depressive disorder (MDD) may be influenced by early life stress and antidepressant treatment. The present structural MRI study aimed to determine the relationship between amygdala, cingulate and subgenual prefrontal cortex volumes in MDD and their associations with child abuse and antidepressants. Right-handed subjects (21-50 years), meeting DSM-IV criteria for MDD, either with (n=19) or without (n=20) childhood sexual or physical abuse. Healthy controls (n=34) were matched for age, sex, education and smoking. 3D-MPRAGE images with a spatial resolution of 1.5 mm×1.0 mm×1.0 mm were acquired with a Siemens Sonata 1.5 T system. Volumes of subgenual prefrontal cortex, amygdala and affective, cognitive, superior and posterior divisions of cingulate cortex were analyzed using DISPLAY software using reliable volumetric protocols. Groups were compared using ANCOVA, with intracranial volume as a covariate. MDD subjects had low cingulate (cognitive division) and high amygdala volumes. Low cingulate volume was related to abuse and treatment history. Amygdala volume was predicted by subgenual prefrontal and cingulate (cognitive division) volumes and the presence of paracingulate cortex. This study was cross sectional and the sample size was limited for subgroup and correlational analyses. Our data suggest that MDD may be associated with alterations in anterior cingulate cortex and amygdala. Morphological variation, early stress and stress-protective factors may contribute to differences in fronto-limbic structures in MDD. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Dual-Gated Volumetric Modulated Arc Therapy.

    PubMed

    Fahimian, Benjamin; Wu, Junqing; Wu, Huanmei; Geneser, Sarah; Xing, Lei

    2014-09-25

    Gated Volumetric Modulated Arc Therapy (VMAT) is an emerging radiation therapy modality for treatment of tumors affected by respiratory motion. However, gating significantly prolongs the treatment time, as delivery is only activated during a single respiratory phase. To enhance the efficiency of gated VMAT delivery, a novel dual-gated VMAT (DG-VMAT) technique, in which delivery is executed at both exhale and inhale phases in a given arc rotation, is developed and experimentally evaluated. Arc delivery at two phases is realized by sequentially interleaving control points consisting of MUs, MLC sequences, and angles of VMAT plans generated at the exhale and inhale phases. Dual-gated delivery is initiated when a respiration gating signal enters the exhale window; when the exhale delivery concludes, the beam turns off and the gantry rolls back to the starting position for the inhale window. The process is then repeated until both inhale and exhale arcs are fully delivered. DG-VMAT plan delivery accuracy was assessed using a pinpoint chamber and diode array phantom undergoing programmed motion. DG-VMAT delivery was experimentally implemented through custom XML scripting in Varian's TrueBeam™ STx Developer Mode. Relative to single gated delivery at exhale, the treatment time was improved by 95.5% for a sinusoidal breathing pattern. The pinpoint chamber dose measurement agreed with the calculated dose within 0.7%. For the DG-VMAT delivery, 97.5% of the diode array measurements passed the 3%/3 mm gamma criterion. The feasibility of DG-VMAT delivery scheme has been experimentally demonstrated for the first time. By leveraging the stability and natural pauses that occur at end-inspiration and end-exhalation, DG-VMAT provides a practical method for enhancing gated delivery efficiency by up to a factor of two.

  9. Subcortical volumetric abnormalities in bipolar disorder

    PubMed Central

    Hibar, D P; Westlye, L T; van Erp, T G M; Rasmussen, J; Leonardo, C D; Faskowitz, J; Haukvik, U K; Hartberg, C B; Doan, N T; Agartz, I; Dale, A M; Gruber, O; Krämer, B; Trost, S; Liberg, B; Abé, C; Ekman, C J; Ingvar, M; Landén, M; Fears, S C; Freimer, N B; Bearden, C E; Sprooten, E; Glahn, D C; Pearlson, G D; Emsell, L; Kenney, J; Scanlon, C; McDonald, C; Cannon, D M; Almeida, J; Versace, A; Caseras, X; Lawrence, N S; Phillips, M L; Dima, D; Delvecchio, G; Frangou, S; Satterthwaite, T D; Wolf, D; Houenou, J; Henry, C; Malt, U F; Bøen, E; Elvsåshagen, T; Young, A H; Lloyd, A J; Goodwin, G M; Mackay, C E; Bourne, C; Bilderbeck, A; Abramovic, L; Boks, M P; van Haren, N E M; Ophoff, R A; Kahn, R S; Bauer, M; Pfennig, A; Alda, M; Hajek, T; Mwangi, B; Soares, J C; Nickson, T; Dimitrova, R; Sussmann, J E; Hagenaars, S; Whalley, H C; McIntosh, A M; Thompson, P M; Andreassen, O A

    2016-01-01

    Considerable uncertainty exists about the defining brain changes associated with bipolar disorder (BD). Understanding and quantifying the sources of uncertainty can help generate novel clinical hypotheses about etiology and assist in the development of biomarkers for indexing disease progression and prognosis. Here we were interested in quantifying case–control differences in intracranial volume (ICV) and each of eight subcortical brain measures: nucleus accumbens, amygdala, caudate, hippocampus, globus pallidus, putamen, thalamus, lateral ventricles. In a large study of 1710 BD patients and 2594 healthy controls, we found consistent volumetric reductions in BD patients for mean hippocampus (Cohen's d=−0.232; P=3.50 × 10−7) and thalamus (d=−0.148; P=4.27 × 10−3) and enlarged lateral ventricles (d=−0.260; P=3.93 × 10−5) in patients. No significant effect of age at illness onset was detected. Stratifying patients based on clinical subtype (BD type I or type II) revealed that BDI patients had significantly larger lateral ventricles and smaller hippocampus and amygdala than controls. However, when comparing BDI and BDII patients directly, we did not detect any significant differences in brain volume. This likely represents similar etiology between BD subtype classifications. Exploratory analyses revealed significantly larger thalamic volumes in patients taking lithium compared with patients not taking lithium. We detected no significant differences between BDII patients and controls in the largest such comparison to date. Findings in this study should be interpreted with caution and with careful consideration of the limitations inherent to meta-analyzed neuroimaging comparisons. PMID:26857596

  10. Subcortical volumetric abnormalities in bipolar disorder.

    PubMed

    Hibar, D P; Westlye, L T; van Erp, T G M; Rasmussen, J; Leonardo, C D; Faskowitz, J; Haukvik, U K; Hartberg, C B; Doan, N T; Agartz, I; Dale, A M; Gruber, O; Krämer, B; Trost, S; Liberg, B; Abé, C; Ekman, C J; Ingvar, M; Landén, M; Fears, S C; Freimer, N B; Bearden, C E; Sprooten, E; Glahn, D C; Pearlson, G D; Emsell, L; Kenney, J; Scanlon, C; McDonald, C; Cannon, D M; Almeida, J; Versace, A; Caseras, X; Lawrence, N S; Phillips, M L; Dima, D; Delvecchio, G; Frangou, S; Satterthwaite, T D; Wolf, D; Houenou, J; Henry, C; Malt, U F; Bøen, E; Elvsåshagen, T; Young, A H; Lloyd, A J; Goodwin, G M; Mackay, C E; Bourne, C; Bilderbeck, A; Abramovic, L; Boks, M P; van Haren, N E M; Ophoff, R A; Kahn, R S; Bauer, M; Pfennig, A; Alda, M; Hajek, T; Mwangi, B; Soares, J C; Nickson, T; Dimitrova, R; Sussmann, J E; Hagenaars, S; Whalley, H C; McIntosh, A M; Thompson, P M; Andreassen, O A

    2016-12-01

    Considerable uncertainty exists about the defining brain changes associated with bipolar disorder (BD). Understanding and quantifying the sources of uncertainty can help generate novel clinical hypotheses about etiology and assist in the development of biomarkers for indexing disease progression and prognosis. Here we were interested in quantifying case-control differences in intracranial volume (ICV) and each of eight subcortical brain measures: nucleus accumbens, amygdala, caudate, hippocampus, globus pallidus, putamen, thalamus, lateral ventricles. In a large study of 1710 BD patients and 2594 healthy controls, we found consistent volumetric reductions in BD patients for mean hippocampus (Cohen's d=-0.232; P=3.50 × 10(-7)) and thalamus (d=-0.148; P=4.27 × 10(-3)) and enlarged lateral ventricles (d=-0.260; P=3.93 × 10(-5)) in patients. No significant effect of age at illness onset was detected. Stratifying patients based on clinical subtype (BD type I or type II) revealed that BDI patients had significantly larger lateral ventricles and smaller hippocampus and amygdala than controls. However, when comparing BDI and BDII patients directly, we did not detect any significant differences in brain volume. This likely represents similar etiology between BD subtype classifications. Exploratory analyses revealed significantly larger thalamic volumes in patients taking lithium compared with patients not taking lithium. We detected no significant differences between BDII patients and controls in the largest such comparison to date. Findings in this study should be interpreted with caution and with careful consideration of the limitations inherent to meta-analyzed neuroimaging comparisons.

  11. Volumetric Modulated Arc Radiotherapy for Vestibular Schwannomas

    SciTech Connect

    Lagerwaard, Frank J. Meijer, Otto W.M.; Hoorn, Elles A.P. van der; Verbakel, Wilko; Slotman, Ben J.; Senan, Suresh

    2009-06-01

    Purpose: To evaluate volumetric modulated arc radiotherapy (RapidArc [RA]), a novel approach allowing for rapid treatment delivery, for the treatment of vestibular schwannoma (VS). Methods and Materials: The RA plans were generated for a small (0.5 cm{sup 3}), intermediate (2.8 cm{sup 3}), and large (14.8 cm{sup 3}) VS. The prescription dose was 12.5 Gy to the encompassing 80% isodose. The RA plans were compared with conventional radiosurgery plans using both a single dynamic conformal arc (1DCA) and five noncoplanar dynamic conformal arcs (5DCA). Conformity indices (CI) and dose-volume histograms of critical organs were compared. The RA plan for the medium-sized VS was measured in a phantom using Gafchromic EBT films and compared with calculated dose distributions. Results: The RA planning was completed within 30 min in all cases, and calculated treatment delivery time (after patient setup) was 5 min vs. 20 min for 5DCA. A superior CI was achieved with RA, with a substantial decrease in low-dose irradiation of the normal brain achieved relative to 5DCA plans. Maximum doses to critical organs were similar for RA and 5DCA but were higher for 1DCA. Film measurements showed the differences between calculated and measured doses to be smaller than 1.5% in the high-dose area and smaller than 3% in the low-dose area. Conclusion: The RA plans consistently achieved a higher CI and decrease in areas of low-dose irradiation. This, together with shorter treatment delivery times, has led to RA replacing our conventional five-arc radiosurgery technique for VS.

  12. Soft bilateral filtering volumetric shadows using cube shadow maps

    PubMed Central

    Ali, Hatam H.; Sunar, Mohd Shahrizal; Kolivand, Hoshang

    2017-01-01

    Volumetric shadows often increase the realism of rendered scenes in computer graphics. Typical volumetric shadows techniques do not provide a smooth transition effect in real-time with conservation on crispness of boundaries. This research presents a new technique for generating high quality volumetric shadows by sampling and interpolation. Contrary to conventional ray marching method, which requires extensive time, this proposed technique adopts downsampling in calculating ray marching. Furthermore, light scattering is computed in High Dynamic Range buffer to generate tone mapping. The bilateral interpolation is used along a view rays to smooth transition of volumetric shadows with respect to preserving-edges. In addition, this technique applied a cube shadow map to create multiple shadows. The contribution of this technique isreducing the number of sample points in evaluating light scattering and then introducing bilateral interpolation to improve volumetric shadows. This contribution is done by removing the inherent deficiencies significantly in shadow maps. This technique allows obtaining soft marvelous volumetric shadows, having a good performance and high quality, which show its potential for interactive applications. PMID:28632740

  13. Visualization and volumetric structures from MR images of the brain

    SciTech Connect

    Parvin, B.; Johnston, W.; Robertson, D.

    1994-03-01

    Pinta is a system for segmentation and visualization of anatomical structures obtained from serial sections reconstructed from magnetic resonance imaging. The system approaches the segmentation problem by assigning each volumetric region to an anatomical structure. This is accomplished by satisfying constraints at the pixel level, slice level, and volumetric level. Each slice is represented by an attributed graph, where nodes correspond to regions and links correspond to the relations between regions. These regions are obtained by grouping pixels based on similarity and proximity. The slice level attributed graphs are then coerced to form a volumetric attributed graph, where volumetric consistency can be verified. The main novelty of our approach is in the use of the volumetric graph to ensure consistency from symbolic representations obtained from individual slices. In this fashion, the system allows errors to be made at the slice level, yet removes them when the volumetric consistency cannot be verified. Once the segmentation is complete, the 3D surfaces of the brain can be constructed and visualized.

  14. In vivo volumetric imaging of the human corneo-scleral limbus with spectral domain OCT

    PubMed Central

    Bizheva, Kostadinka; Hutchings, Natalie; Sorbara, Luigina; Moayed, Alireza A.; Simpson, Trefford

    2011-01-01

    The limbus is the structurally rich transitional region of tissue between the cornea on one side, and the sclera and conjunctiva on the other. This zone, among other things, contains nerves passing to the cornea, blood and lymph vasculature for oxygen and nutrient delivery and for waste, CO2 removal and drainage of the aqueous humour. In addition, the limbus contains stem cells responsible for the existence and healing of the corneal epithelium. Here we present 3D images of the healthy human limbus, acquired in vivo with a spectral domain optical coherence tomography system operating at 1060nm. Cross-sectional and volumetric images were acquired from temporal and nasal locations in the human limbus with ~3µm x 18µm (axial x lateral) resolution in biological tissue at the rate of 92,000 A-scans/s. The imaging enabled detailed mapping of the corneo-scleral tissue morphology, and visualization of structural details such as the Vogt palisades, the blood and lymph vasculature including the Schlemm’s canal and the trabecular meshwork, as well as corneal nerve fiber bundles. Non-invasive, volumetric, high resolution imaging reveals fine details of the normal human limbal structure, and promises to provide invaluable information about its changes in health and disease as well as during and after corneal surgery. PMID:21750758

  15. Volumetric Medical Image Coding: An Object-based, Lossy-to-lossless and Fully Scalable Approach.

    PubMed

    Danyali, Habibiollah; Mertins, Alfred

    2011-01-01

    In this article, an object-based, highly scalable, lossy-to-lossless 3D wavelet coding approach for volumetric medical image data (e.g., magnetic resonance (MR) and computed tomography (CT)) is proposed. The new method, called 3DOBHS-SPIHT, is based on the well-known set partitioning in the hierarchical trees (SPIHT) algorithm and supports both quality and resolution scalability. The 3D input data is grouped into groups of slices (GOS) and each GOS is encoded and decoded as a separate unit. The symmetric tree definition of the original 3DSPIHT is improved by introducing a new asymmetric tree structure. While preserving the compression efficiency, the new tree structure allows for a small size of each GOS, which not only reduces memory consumption during the encoding and decoding processes, but also facilitates more efficient random access to certain segments of slices. To achieve more compression efficiency, the algorithm only encodes the main object of interest in each 3D data set, which can have any arbitrary shape, and ignores the unnecessary background. The experimental results on some MR data sets show the good performance of the 3DOBHS-SPIHT algorithm for multi-resolution lossy-to-lossless coding. The compression efficiency, full scalability, and object-based features of the proposed approach, beside its lossy-to-lossless coding support, make it a very attractive candidate for volumetric medical image information archiving and transmission applications.

  16. Volumetric Medical Image Coding: An Object-based, Lossy-to-lossless and Fully Scalable Approach

    PubMed Central

    Danyali, Habibiollah; Mertins, Alfred

    2011-01-01

    In this article, an object-based, highly scalable, lossy-to-lossless 3D wavelet coding approach for volumetric medical image data (e.g., magnetic resonance (MR) and computed tomography (CT)) is proposed. The new method, called 3DOBHS-SPIHT, is based on the well-known set partitioning in the hierarchical trees (SPIHT) algorithm and supports both quality and resolution scalability. The 3D input data is grouped into groups of slices (GOS) and each GOS is encoded and decoded as a separate unit. The symmetric tree definition of the original 3DSPIHT is improved by introducing a new asymmetric tree structure. While preserving the compression efficiency, the new tree structure allows for a small size of each GOS, which not only reduces memory consumption during the encoding and decoding processes, but also facilitates more efficient random access to certain segments of slices. To achieve more compression efficiency, the algorithm only encodes the main object of interest in each 3D data set, which can have any arbitrary shape, and ignores the unnecessary background. The experimental results on some MR data sets show the good performance of the 3DOBHS-SPIHT algorithm for multi-resolution lossy-to-lossless coding. The compression efficiency, full scalability, and object-based features of the proposed approach, beside its lossy-to-lossless coding support, make it a very attractive candidate for volumetric medical image information archiving and transmission applications. PMID:22606653

  17. Volumetric measurement of the pontomesencephalic cistern in patients with trigeminal neuralgia and healthy controls.

    PubMed

    Rasche, Dirk; Kress, Bodo; Stippich, Christoph; Nennig, Ernst; Sartor, Klaus; Tronnier, Volker M

    2006-09-01

    Most so-called idiopathic trigeminal neuralgias (TN) are caused by neurovascular compression. Does the size of the cerebellopontine cistern play a role in favoring a neurovascular conflict? The aim of this prospective study was to measure the volume of the parapontine cistern in patients with idiopathic TN and to perform a comparison with healthy controls. In 25 patients with unilateral idiopathic TN and 17 healthy participants, high-resolution 1.5-T magnetic resonance imaging scans of the parapontine region and the trigeminal nerve were performed. A coronal T2-weighted, true fast imaging steady-state precession sequence with a slice thickness of 0.9 mm was used to define the surrounding cerebrospinal fluid space from the trigeminal root entry zone to Meckel's cave. The volume of the pontomesencephalic cistern was calculated using a standardized method. The mean difference of the volume of the affected and opposite side was 13% in patients with TN. In all patients, a significantly smaller volume of the cistern was found on the affected side (P < 0.01). Healthy controls showed a mean volumetric side difference of 9%, which was not significant (P > 0.05). High-resolution magnetic resonance imaging scans are able to demonstrate significant volumetric differences of the pontomesencephalic cistern in patients with unilateral TN. A smaller cistern may be correlated with the occurrence of a neurovascular compression, and these findings support the neurovascular compression theory in idiopathic TN.

  18. Volumetric Forest Change Detection Through Vhr Satellite Imagery

    NASA Astrophysics Data System (ADS)

    Akca, Devrim; Stylianidis, Efstratios; Smagas, Konstantinos; Hofer, Martin; Poli, Daniela; Gruen, Armin; Sanchez Martin, Victor; Altan, Orhan; Walli, Andreas; Jimeno, Elisa; Garcia, Alejandro

    2016-06-01

    Quick and economical ways of detecting of planimetric and volumetric changes of forest areas are in high demand. A research platform, called FORSAT (A satellite processing platform for high resolution forest assessment), was developed for the extraction of 3D geometric information from VHR (very-high resolution) imagery from satellite optical sensors and automatic change detection. This 3D forest information solution was developed during a Eurostars project. FORSAT includes two main units. The first one is dedicated to the geometric and radiometric processing of satellite optical imagery and 2D/3D information extraction. This includes: image radiometric pre-processing, image and ground point measurement, improvement of geometric sensor orientation, quasiepipolar image generation for stereo measurements, digital surface model (DSM) extraction by using a precise and robust image matching approach specially designed for VHR satellite imagery, generation of orthoimages, and 3D measurements in single images using mono-plotting and in stereo images as well as triplets. FORSAT supports most of the VHR optically imagery commonly used for civil applications: IKONOS, OrbView - 3, SPOT - 5 HRS, SPOT - 5 HRG, QuickBird, GeoEye-1, WorldView-1/2, Pléiades 1A/1B, SPOT 6/7, and sensors of similar type to be expected in the future. The second unit of FORSAT is dedicated to 3D surface comparison for change detection. It allows users to import digital elevation models (DEMs), align them using an advanced 3D surface matching approach and calculate the 3D differences and volume changes between epochs. To this end our 3D surface matching method LS3D is being used. FORSAT is a single source and flexible forest information solution with a very competitive price/quality ratio, allowing expert and non-expert remote sensing users to monitor forests in three and four dimensions from VHR optical imagery for many forest information needs. The capacity and benefits of FORSAT have been tested in

  19. Ultra-high resolution polarization-sensitive optical coherence microscopy for brain imaging at 6 um, 3.4 um and 1.3 um resolution (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Wang, Hui; Akkin, Taner; Magnain, Caroline V.; Yaseen, Mohammad A.; Cramer, Avilash; Wang, Ruopeng; Sakadžic, Sava; Boas, David A.

    2016-03-01

    Neuroanatomical pathways form the basis for functional activity of brain circuits. In the past, we developed a polarization-sensitive optical coherence tomography with serial scanning to achieve large-scale brain imaging. The system was able to visualize 3D fiber tracts of ~20 um in diameter. To investigate the neuroanatomical pathways at finer scales, we have now built a polarization-maintaining fiber based ultra-high resolution polarization-sensitive optical coherence microscope (PS-OCM) at 1300 nm. The PS-OCM has an axial resolution of 3.5 um in tissue. The detection setup consists of two spectrometers, acquiring spectral interference on orthogonal polarization channels. With a single measurement, the setup generates four contrasts: reflectivity, cross-polarization, retardance and optic axis orientation. To investigate the capability of PS-OCM at different resolutions, we used three microscope objectives that yield lateral resolutions of 6.0 um, 3.4 um and 1.3 um. Blocks of formalin fixed mouse brain and human brain were scanned. The cross-polarization and retardance images clearly depict the neuronal fiber structures, which are comparable with that generated by the maximum projection of volumetric reflectivity data. The optic axis orientation quantifies the in-plane fiber orientation. With the lateral resolution of 1.3 um, the retardance contrast is weak in white matter due to the shallow depth of focus. Overall, the ultra-high resolution PS-OCM provides a new tool to reveal neuroanatomical maps in the brain at cellular resolution.

  20. Three-axis digital holographic microscopy for high speed volumetric imaging.

    PubMed

    Saglimbeni, F; Bianchi, S; Lepore, A; Di Leonardo, R

    2014-06-02

    Digital Holographic Microscopy allows to numerically retrieve three dimensional information encoded in a single 2D snapshot of the coherent superposition of a reference and a scattered beam. Since no mechanical scans are involved, holographic techniques have a superior performance in terms of achievable frame rates. Unfortunately, numerical reconstructions of scattered field by back-propagation leads to a poor axial resolution. Here we show that overlapping the three numerical reconstructions obtained by tilted red, green and blue beams results in a great improvement over the axial resolution and sectioning capabilities of holographic microscopy. A strong reduction in the coherent background noise is also observed when combining the volumetric reconstructions of the light fields at the three different wavelengths. We discuss the performance of our technique with two test objects: an array of four glass beads that are stacked along the optical axis and a freely diffusing rod shaped E.coli bacterium.

  1. Volumetric modulated arc radiotherapy for esophageal cancer

    SciTech Connect

    Vivekanandan, Nagarajan; Sriram, Padmanaban; Syam Kumar, S.A.; Bhuvaneswari, Narayanan; Saranya, Kamalakannan

    2012-04-01

    A treatment planning study was performed to evaluate the performance of volumetric arc modulation with RapidArc (RA) against 3D conformal radiation therapy (3D-CRT) and conventional intensity-modulated radiation therapy (IMRT) techniques for esophageal cancer. Computed tomgraphy scans of 10 patients were included in the study. 3D-CRT, 4-field IMRT, and single-arc and double-arc RA plans were generated with the aim to spare organs at risk (OAR) and healthy tissue while enforcing highly conformal target coverage. The planning objective was to deliver 54 Gy to the planning target volume (PTV) in 30 fractions. Plans were evaluated based on target conformity and dose-volume histograms of organs at risk (lung, spinal cord, and heart). The monitor unit (MU) and treatment delivery time were also evaluated to measure the treatment efficiency. The IMRT plan improves target conformity and spares OAR when compared with 3D-CRT. Target conformity improved with RA plans compared with IMRT. The mean lung dose was similar in all techniques. However, RA plans showed a reduction in the volume of the lung irradiated at V{sub 20Gy} and V{sub 30Gy} dose levels (range, 4.62-17.98%) compared with IMRT plans. The mean dose and D{sub 35%} of heart for the RA plans were better than the IMRT by 0.5-5.8%. Mean V{sub 10Gy} and integral dose to healthy tissue were almost similar in all techniques. But RA plans resulted in a reduced low-level dose bath (15-20 Gy) in the range of 14-16% compared with IMRT plans. The average MU needed to deliver the prescribed dose by RA technique was reduced by 20-25% compared with IMRT technique. The preliminary study on RA for esophageal cancers showed improvements in sparing OAR and healthy tissue with reduced beam-on time, whereas only double-arc RA offered improved target coverage compared with IMRT and 3D-CRT plans.

  2. Hybrid Multiphoton Volumetric Functional Imaging of Large Scale Bioengineered Neuronal Networks

    PubMed Central

    Paluch, Shir; Dvorkin, Roman; Brosh, Inbar; Shoham, Shy

    2014-01-01

    Planar neural networks and interfaces serve as versatile in vitro models of central nervous system physiology, but adaptations of related methods to three dimensions (3D) have met with limited success. Here, we demonstrate for the first time volumetric functional imaging in a bio-engineered neural tissue growing in a transparent hydrogel with cortical cellular and synaptic densities, by introducing complementary new developments in nonlinear microscopy and neural tissue engineering. Our system uses a novel hybrid multiphoton microscope design combining a 3D scanning-line temporal-focusing subsystem and a conventional laser-scanning multiphoton microscope to provide functional and structural volumetric imaging capabilities: dense microscopic 3D sampling at tens of volumes/sec of structures with mm-scale dimensions containing a network of over 1000 developing cells with complex spontaneous activity patterns. These developments open new opportunities for large-scale neuronal interfacing and for applications of 3D engineered networks ranging from basic neuroscience to the screening of neuroactive substances. PMID:24898000

  3. Hybrid multiphoton volumetric functional imaging of large-scale bioengineered neuronal networks

    NASA Astrophysics Data System (ADS)

    Dana, Hod; Marom, Anat; Paluch, Shir; Dvorkin, Roman; Brosh, Inbar; Shoham, Shy

    2014-06-01

    Planar neural networks and interfaces serve as versatile in vitro models of central nervous system physiology, but adaptations of related methods to three dimensions (3D) have met with limited success. Here, we demonstrate for the first time volumetric functional imaging in a bioengineered neural tissue growing in a transparent hydrogel with cortical cellular and synaptic densities, by introducing complementary new developments in nonlinear microscopy and neural tissue engineering. Our system uses a novel hybrid multiphoton microscope design combining a 3D scanning-line temporal-focusing subsystem and a conventional laser-scanning multiphoton microscope to provide functional and structural volumetric imaging capabilities: dense microscopic 3D sampling at tens of volumes per second of structures with mm-scale dimensions containing a network of over 1,000 developing cells with complex spontaneous activity patterns. These developments open new opportunities for large-scale neuronal interfacing and for applications of 3D engineered networks ranging from basic neuroscience to the screening of neuroactive substances.

  4. A prototype table-top inverse-geometry volumetric CT system.

    PubMed

    Schmidt, Taly Gilat; Star-Lack, Josh; Bennett, N Robert; Mazin, Samuel R; Solomon, Edward G; Fahrig, Rebecca; Pelc, Norbert J

    2006-06-01

    A table-top volumetric CT system has been implemented that is able to image a 5-cm-thick volume in one circular scan with no cone-beam artifacts. The prototype inverse-geometry CT (IGCT) scanner consists of a large-area, scanned x-ray source and a detector array that is smaller in the transverse direction. The IGCT geometry provides sufficient volumetric sampling because the source and detector have the same axial, or slice direction, extent. This paper describes the implementation of the table-top IGCT scanner, which is based on the NexRay Scanning-Beam Digital X-ray system (NexRay, Inc., Los Gatos, CA) and an investigation of the system performance. The alignment and flat-field calibration procedures are described, along with a summary of the reconstruction algorithm. The resolution and noise performance of the prototype IGCT system are studied through experiments and further supported by analytical predictions and simulations. To study the presence of cone-beam artifacts, a "Defrise" phantom was scanned on both the prototype IGCT scanner and a micro CT system with a +/-5 cone angle for a 4.5-cm volume thickness. Images of inner ear specimens are presented and compared to those from clinical CT systems. Results showed that the prototype IGCT system has a 0.25-mm isotropic resolution and that noise comparable to that from a clinical scanner with equivalent spatial resolution is achievable. The measured MTF and noise values agreed reasonably well with theoretical predictions and computer simulations. The IGCT system was able to faithfully reconstruct the laminated pattern of the Defrise phantom while the micro CT system suffered severe cone-beam artifacts for the same object. The inner ear acquisition verified that the IGCT system can image a complex anatomical object, and the resulting images exhibited more high-resolution details than the clinical CT acquisition. Overall, the successful implementation of the prototype system supports the IGCT concept for single

  5. Volumetric image display for complex 3D data visualization

    NASA Astrophysics Data System (ADS)

    Tsao, Che-Chih; Chen, Jyh Shing

    2000-05-01

    A volumetric image display is a new display technology capable of displaying computer generated 3D images in a volumetric space. Many viewers can walk around the display and see the image from omni-directions simultaneously without wearing any glasses. The image is real and possesses all major elements in both physiological and psychological depth cues. Due to the volumetric nature of its image, the VID can provide the most natural human-machine interface in operations involving 3D data manipulation and 3D targets monitoring. The technology creates volumetric 3D images by projecting a series of profiling images distributed in the space form a volumetric image because of the after-image effect of human eyes. Exemplary applications in biomedical image visualization were tested on a prototype display, using different methods to display a data set from Ct-scans. The features of this display technology make it most suitable for applications that require quick understanding of the 3D relations, need frequent spatial interactions with the 3D images, or involve time-varying 3D data. It can also be useful for group discussion and decision making.

  6. Volumetric loss quantification using ultrasonic inductively coupled transducers

    NASA Astrophysics Data System (ADS)

    Gong, Peng; Hay, Thomas R.; Greve, David W.; Oppenheim, Irving J.

    2015-03-01

    The pulse-echo method is widely used for plate and pipe thickness measurement. However, the pulse echo method does not work well for detecting localized volumetric loss in thick-wall tubes, as created by erosion damage, when the morphology of volumetric loss is irregular and can reflect ultrasonic pulses away from the transducer, making it difficult to detect an echo. In this paper, we propose a novel method using an inductively coupled transducer to generate longitudinal waves propagating in a thick-wall aluminum tube for the volumetric loss quantification. In the experiment, longitudinal waves exhibit diffraction effects during the propagation which can be explained by the Huygens-Fresnel principle. The diffractive waves are also shown to be significantly delayed by the machined volumetric loss on the inside surface of the thick-wall aluminum tube. It is also shown that the inductively coupled transducers can generate and receive similar ultrasonic waves to those from wired transducers, and the inductively coupled transducers perform as well as the wired transducers in the volumetric loss quantification when other conditions are the same.

  7. On the use of volumetric strain meters to infer additional characteristics of short-period seismic radiation

    USGS Publications Warehouse

    Borcherdt, R.D.; Johnston, M.J.S.; Glassmoyer, G.

    1989-01-01

    Volumetric strain meters (Sacks-Evertson design) are installed at 15 sites along the San Andreas fault system, to monitor long-term strain changes for earthquake prediction. Deployment of portable broadband, high-resolution digital recorders (GEOS) at several of the sites extends the detection band for volumetric strain to periods shorter than 5 ?? 10-2 sec and permits the simultaneous observation of seismic radiation fields using conventional short-period pendulum seismometers. Recordings of local and regional earthquakes indicate that dilatometers respond to P energy but not direct shear energy and that straingrams can be used to resolve superimposed reflect P and S waves for inference of wave characteristics not permitted by either sensor alone. Simultaneous measurements of incident P- and S-wave amplitudes are used to introduce a technique for single-station estimates of wave field inhomogeneity, free-surface reflection coefficients and local material P velocity. -from Authors

  8. Modelling volumetric growth in a thick walled fibre reinforced artery

    NASA Astrophysics Data System (ADS)

    Eriksson, T. S. E.; Watton, P. N.; Luo, X. Y.; Ventikos, Y.

    2014-12-01

    A novel framework for simulating growth and remodelling (G&R) of a fibre-reinforced artery, including volumetric adaption, is proposed. We show how to implement this model into a finite element framework and propose and examine two underlying assumptions for modelling growth, namely constant individual density (CID) or adaptive individual density (AID). Moreover, we formulate a novel approach which utilises a combination of both AID and CID to simulate volumetric G&R for a tissue composed of several different constituents. We consider a special case of the G&R of an artery subjected to prescribed elastin degradation and we theorise on the assumptions and suitability of CID, AID and the mixed approach for modelling arterial biology. For simulating the volumetric changes that occur during aneurysm enlargement, we observe that it is advantageous to describe the growth of collagen using CID whilst it is preferable to model the atrophy of elastin using AID.

  9. Automated Segmentation and Shape Characterization of Volumetric Data

    PubMed Central

    Galinsky, Vitaly L.; Frank, Lawrence R.

    2015-01-01

    Characterization of complex shapes embedded within volumetric data is an important step in a wide range of applications. Standard approaches to this problem employ surface based methods that require inefficient, time consuming, and error prone steps of surface segmentation and inflation to satisfy the uniqueness or stability of subsequent surface fitting algorithms. Here we present a novel method based on a spherical wave decomposition (SWD) of the data that overcomes several of these limitations by directly analyzing the entire data volume, obviating the segmentation, inflation, and surface fitting steps, significantly reducing the computational time and eliminating topological errors while providing a more detailed quantitative description based upon a more complete theoretical framework of volumetric data. The method is demonstrated and compared to the current state-of-the-art neuroimaging methods for segmentation and characterization of volumetric magnetic resonance imaging data of the human brain. PMID:24521852

  10. A high volume, high throughput volumetric sorption analyzer

    NASA Astrophysics Data System (ADS)

    Soo, Y. C.; Beckner, M.; Romanos, J.; Wexler, C.; Pfeifer, P.; Buckley, P.; Clement, J.

    2011-03-01

    In this talk we will present an overview of our new Hydrogen Test Fixture (HTF) constructed by the Midwest Research Institute for The Alliance for Collaborative Research in Alternative Fuel Technology to test activated carbon monoliths for hydrogen gas storage. The HTF is an automated, computer-controlled volumetric instrument for rapid screening and manipulation of monoliths under an inert atmosphere (to exclude degradation of carbon from exposure to oxygen). The HTF allows us to measure large quantity (up to 500 g) of sample in a 0.5 l test tank, making our results less sensitive to sample inhomogeneity. The HTF can measure isotherms at pressures ranging from 1 to 300 bar at room temperature. For comparison, other volumetric instruments such as Hiden Isochema's HTP-1 Volumetric Analyser can only measure carbon samples up to 150 mg at pressures up to 200 bar. Work supported by the US DOD Contract # N00164-08-C-GS37.

  11. Full-spectrum volumetric solar thermal conversion via photonic nanofluids.

    PubMed

    Liu, Xianglei; Xuan, Yimin

    2017-07-24

    Volumetric solar thermal conversion is an emerging technique for a plethora of applications such as solar thermal power generation, desalination, and solar water splitting. However, achieving broadband solar thermal absorption via dilute nanofluids is still a daunting challenge. In this work, full-spectrum volumetric solar thermal conversion is demonstrated over a thin layer of the proposed 'photonic nanofluids'. The underlying mechanism is found to be the photonic superposition of core resonances, shell plasmons, and core-shell resonances at different wavelengths, whose coexistence is enabled by the broken symmetry of specially designed composite nanoparticles, i.e., Janus nanoparticles. The solar thermal conversion efficiency can be improved by 10.8% compared with core-shell nanofluids. The extinction coefficient of Janus dimers with various configurations is also investigated to unveil the effects of particle couplings. This work provides the possibility to achieve full-spectrum volumetric solar thermal conversion, and may have potential applications in efficient solar energy harvesting and utilization.

  12. Evaluation of feature-based 3-d registration of probabilistic volumetric scenes

    NASA Astrophysics Data System (ADS)

    Restrepo, Maria I.; Ulusoy, Ali O.; Mundy, Joseph L.

    2014-12-01

    Automatic estimation of the world surfaces from aerial images has seen much attention and progress in recent years. Among current modeling technologies, probabilistic volumetric models (PVMs) have evolved as an alternative representation that can learn geometry and appearance in a dense and probabilistic manner. Recent progress, in terms of storage and speed, achieved in the area of volumetric modeling, opens the opportunity to develop new frameworks that make use of the PVM to pursue the ultimate goal of creating an entire map of the earth, where one can reason about the semantics and dynamics of the 3-d world. Aligning 3-d models collected at different time-instances constitutes an important step for successful fusion of large spatio-temporal information. This paper evaluates how effectively probabilistic volumetric models can be aligned using robust feature-matching techniques, while considering different scenarios that reflect the kind of variability observed across aerial video collections from different time instances. More precisely, this work investigates variability in terms of discretization, resolution and sampling density, errors in the camera orientation, and changes in illumination and geographic characteristics. All results are given for large-scale, outdoor sites. In order to facilitate the comparison of the registration performance of PVMs to that of other 3-d reconstruction techniques, the registration pipeline is also carried out using Patch-based Multi-View Stereo (PMVS) algorithm. Registration performance is similar for scenes that have favorable geometry and the appearance characteristics necessary for high quality reconstruction. In scenes containing trees, such as a park, or many buildings, such as a city center, registration performance is significantly more accurate when using the PVM.

  13. Cost-effectiveness of volumetric alcohol taxation in Australia.

    PubMed

    Byrnes, Joshua M; Cobiac, Linda J; Doran, Christopher M; Vos, Theo; Shakeshaft, Anthony P

    2010-04-19

    To estimate the potential health benefits and cost savings of an alcohol tax rate that applies equally to all alcoholic beverages based on their alcohol content (volumetric tax) and to compare the cost savings with the cost of implementation. Mathematical modelling of three scenarios of volumetric alcohol taxation for the population of Australia: (i) no change in deadweight loss, (ii) no change in tax revenue, and (iii) all alcoholic beverages taxed at the same rate as spirits. Estimated change in alcohol consumption, tax revenue and health benefit. The estimated cost of changing to a volumetric tax rate is $18 million. A volumetric tax that is deadweight loss-neutral would increase the cost of beer and wine and reduce the cost of spirits, resulting in an estimated annual increase in taxation revenue of $492 million and a 2.77% reduction in annual consumption of pure alcohol. The estimated net health gain would be 21 000 disability-adjusted life-years (DALYs), with potential cost offsets of $110 million per annum. A tax revenue-neutral scenario would result in an 0.05% decrease in consumption, and a tax on all alcohol at a spirits rate would reduce consumption by 23.85% and increase revenue by $3094 million [corrected]. All volumetric tax scenarios would provide greater health benefits and cost savings to the health sector than the existing taxation system, based on current understandings of alcohol-related health effects. An equalized volumetric tax that would reduce beer and wine consumption while increasing the consumption of spirits would need to be approached with caution. Further research is required to examine whether alcohol-related health effects vary by type of alcoholic beverage independent of the amount of alcohol consumed to provide a strong evidence platform for alcohol taxation policies.

  14. Multiple sparse volumetric priors for distributed EEG source reconstruction.

    PubMed

    Strobbe, Gregor; van Mierlo, Pieter; De Vos, Maarten; Mijović, Bogdan; Hallez, Hans; Van Huffel, Sabine; López, José David; Vandenberghe, Stefaan

    2014-10-15

    We revisit the multiple sparse priors (MSP) algorithm implemented in the statistical parametric mapping software (SPM) for distributed EEG source reconstruction (Friston et al., 2008). In the present implementation, multiple cortical patches are introduced as source priors based on a dipole source space restricted to a cortical surface mesh. In this note, we present a technique to construct volumetric cortical regions to introduce as source priors by restricting the dipole source space to a segmented gray matter layer and using a region growing approach. This extension allows to reconstruct brain structures besides the cortical surface and facilitates the use of more realistic volumetric head models including more layers, such as cerebrospinal fluid (CSF), compared to the standard 3-layered scalp-skull-brain head models. We illustrated the technique with ERP data and anatomical MR images in 12 subjects. Based on the segmented gray matter for each of the subjects, cortical regions were created and introduced as source priors for MSP-inversion assuming two types of head models. The standard 3-layered scalp-skull-brain head models and extended 4-layered head models including CSF. We compared these models with the current implementation by assessing the free energy corresponding with each of the reconstructions using Bayesian model selection for group studies. Strong evidence was found in favor of the volumetric MSP approach compared to the MSP approach based on cortical patches for both types of head models. Overall, the strongest evidence was found in favor of the volumetric MSP reconstructions based on the extended head models including CSF. These results were verified by comparing the reconstructed activity. The use of volumetric cortical regions as source priors is a useful complement to the present implementation as it allows to introduce more complex head models and volumetric source priors in future studies.

  15. CMUT-based volumetric ultrasonic imaging array design for forward looking ICE and IVUS applications

    NASA Astrophysics Data System (ADS)

    Tekes, Coskun; Zahorian, Jaime; Xu, Toby; Rashid, Muhammad W.; Satir, Sarp; Gurun, Gokce; Karaman, Mustafa; Hasler, Jennifer; Degertekin, F. L.

    2013-03-01

    Designing a mechanically flexible catheter based volumetric ultrasonic imaging device for intravascular and intracardiac imaging is challenging due to small transducer area and limited number of cables. With a few parallel channels, synthetic phased array processing is necessary to acquire data from a large number of transducer elements. This increases the data collection time and hence reduces frame rate and causes artifacts due to tissue-transducer motion. Some of these drawbacks can be resolved by different array designs offered by CMUT-on-CMOS approach. We recently implemented a 2.1-mm diameter single chip 10 MHz dual ring CMUT-on-CMOS array for forward looking ICE with 64-transmit and 56-receive elements along with associated electronics. These volumetric arrays have the small element size required by high operating frequencies and achieve sub mm resolution, but the system would be susceptible to motion artifacts. To enable real time imaging with high SNR, we designed novel arrays consisting of multiple defocused annular rings for transmit aperture and a single ring receive array. The annular transmit rings are utilized to act as a high power element by focusing to a virtual ring shaped line behind the aperture. In this case, image reconstruction is performed by only receive beamforming, reducing total required firing steps from 896 to 14 with a trade-off in image resolution. The SNR of system is improved more than 5 dB for the same frequency and frame rate as compared to the dual ring array, which can be utilized to achieve the same resolution by increasing the operating frequency.

  16. CMUT-based Volumetric Ultrasonic Imaging Array Design for Forward Looking ICE and IVUS Applications

    PubMed Central

    Zahorian, Jaime; Xu, Toby; Rashid, Muhammad W.; Satir, Sarp; Gurun, Gokce; Karaman, Mustafa; Hasler, Jennifer; Degertekin, F. Levent

    2014-01-01

    Designing a mechanically flexible catheter based volumetric ultrasonic imaging device for intravascular and intracardiac imaging is challenging due to small transducer area and limited number of cables. With a few parallel channels, synthetic phased array processing is necessary to acquire data from a large number of transducer elements. This increases the data collection time and hence reduces frame rate and causes artifacts due to tissue-transducer motion. Some of these drawbacks can be resolved by different array designs offered by CMUT-on-CMOS approach. We recently implemented a 2.1-mm diameter single chip 10 MHz dual ring CMUT-on-CMOS array for forward looking ICE with 64-transmit and 56-receive elements along with associated electronics. These volumetric arrays have the small element size required by high operating frequencies and achieve sub mm resolution, but the system would be susceptible to motion artifacts. To enable real time imaging with high SNR, we designed novel arrays consisting of multiple defocused annular rings for transmit aperture and a single ring receive array. The annular transmit rings are utilized to act as a high power element by focusing to a virtual ring shaped line behind the aperture. In this case, image reconstruction is performed by only receive beamforming, reducing total required firing steps from 896 to 14 with a trade-off in image resolution. The SNR of system is improved more than 5 dB for the same frequency and frame rate as compared to the dual ring array, which can be utilized to achieve the same resolution by increasing the operating frequency. PMID:23366605

  17. Multi-Atlas Multi-Shape Segmentation of Fetal Brain MRI for Volumetric and Morphometric Analysis of Ventriculomegaly

    PubMed Central

    Gholipour, Ali; Akhondi-Asl, Alireza; Estroff, Judy A.; Warfield, Simon K.

    2012-01-01

    The recent development of motion robust super-resolution fetal brain MRI holds out the potential for dramatic new advances in volumetric and morphometric analysis. Volumetric analysis based on volumetric and morphometric biomarkers of the developing fetal brain must include segmentation. Automatic segmentation of fetal brain MRI is challenging, however, due to the highly variable size and shape of the developing brain; possible structural abnormalities; and the relatively poor resolution of fetal MRI scans. To overcome these limitations, we present a novel, constrained, multi-atlas, multi-shape automatic segmentation method that specifically addresses the challenge of segmenting multiple structures with similar intensity values in subjects with strong anatomic variability. Accordingly, we have applied this method to shape segmentation of normal, dilated, or fused lateral ventricles for quantitative analysis of ventriculomegaly (VM), which is a pivotal finding in the earliest stages of fetal brain development, and warrants further investigation. Utilizing these innovative techniques, we introduce novel volumetric and morphometric biomarkers of VM comparing these values to those that are generated by standard methods of VM analysis, i.e., by measuring the ventricular atrial diameter (AD) on manually selected sections of 2D ultrasound or 2D MRI. To this end, we studied 25 normal and abnormal fetuses in the gestation age (GA) range of 19 to 39 weeks (mean=28.26, stdev=6.56). This heterogenous dataset was essentially used to 1) validate our segmentation method for normal and abnormal ventricles; and 2) show that the proposed biomarkers may provide improved detection of VM as compared to the AD measurement. PMID:22500924

  18. Multi-atlas multi-shape segmentation of fetal brain MRI for volumetric and morphometric analysis of ventriculomegaly.

    PubMed

    Gholipour, Ali; Akhondi-Asl, Alireza; Estroff, Judy A; Warfield, Simon K

    2012-04-15

    The recent development of motion robust super-resolution fetal brain MRI holds out the potential for dramatic new advances in volumetric and morphometric analysis. Volumetric analysis based on volumetric and morphometric biomarkers of the developing fetal brain must include segmentation. Automatic segmentation of fetal brain MRI is challenging, however, due to the highly variable size and shape of the developing brain; possible structural abnormalities; and the relatively poor resolution of fetal MRI scans. To overcome these limitations, we present a novel, constrained, multi-atlas, multi-shape automatic segmentation method that specifically addresses the challenge of segmenting multiple structures with similar intensity values in subjects with strong anatomic variability. Accordingly, we have applied this method to shape segmentation of normal, dilated, or fused lateral ventricles for quantitative analysis of ventriculomegaly (VM), which is a pivotal finding in the earliest stages of fetal brain development, and warrants further investigation. Utilizing these innovative techniques, we introduce novel volumetric and morphometric biomarkers of VM comparing these values to those that are generated by standard methods of VM analysis, i.e., by measuring the ventricular atrial diameter (AD) on manually selected sections of 2D ultrasound or 2D MRI. To this end, we studied 25 normal and abnormal fetuses in the gestation age (GA) range of 19 to 39 weeks (mean=28.26, stdev=6.56). This heterogeneous dataset was essentially used to 1) validate our segmentation method for normal and abnormal ventricles; and 2) show that the proposed biomarkers may provide improved detection of VM as compared to the AD measurement.

  19. Volumetric Hall Effect Tomography – A Feasibility Study

    PubMed Central

    Wen, Han

    2010-01-01

    Hall effect imaging is an ultrasound-based method of mapping spatial variations in the dielectric constants of an acoustically-uniform sample. This paper presents three-dimensional Hall effect images of phantoms obtained by scanning a single transducer across a two-dimensional grid, effectively simulating two-dimensional phased-array signal reception. The experiments demonstrate the feasibility of volumetric Hall effect tomography and show the advantage of volumetric scans over planar scans. The images reflect several limitations of the current scanning method and point to directions for further hardware development. The inherent limitations of Hall effect imaging are also discussed in light of these results. PMID:10604800

  20. Neurologic applications of whole-brain volumetric multidetector computed tomography.

    PubMed

    Snyder, Kenneth V; Mokin, Maxim; Bates, Vernice E

    2014-02-01

    The introduction of computed tomography (CT) scanning in the 1970s revolutionized the way clinicians could diagnose and treat stroke. Subsequent advances in CT technology significantly reduced radiation dose, reduced metallic artifact, and achieved speeds that enable dynamic functional studies. The recent addition of whole-brain volumetric CT perfusion technology has given clinicians a powerful tool to assess parenchymal perfusion parameters as well as visualize dynamic changes in blood vessel flow throughout the brain during a single cardiac cycle. This article reviews clinical applications of volumetric multimodal CT that helped to guide and manage care.

  1. Subcortical and cerebellar volumetric deficits in paediatric sickle cell anaemia.

    PubMed

    Kawadler, Jamie M; Clayden, Jonathan D; Kirkham, Fenella J; Cox, Timothy C; Saunders, Dawn E; Clark, Chris A

    2013-11-01

    Sickle cell anaemia (SCA) is associated with silent cerebral infarction (SCI), affecting white and cortical grey matter, but there are few data on subcortical volumes. We analysed retrospective magnetic resonance imaging (MRI) data in 26 SCA patients and 20 controls, comparing mean subcortical volumes between three groups: controls, SCA with SCI (n = 13) and SCA without visible abnormality (n = 13). Specific volumetric differences were found in the hippocampus, amygdala, pallidum, caudate, putamen, thalamus, and cerebellum. This is the first study to demonstrate subcortical volume change in SCA, with the most severe volumetric deficits occurring in children with SCI seen on MRI.

  2. Volumetric Pricing of Agricultural Water Supplies: A Case Study

    NASA Astrophysics Data System (ADS)

    Griffin, Ronald C.; Perry, Gregory M.

    1985-07-01

    Models of water consumption by rice producers are conceptualized and then estimated using cross-sectional time series data obtained from 16 Texas canal operators for the years 1977-1982. Two alternative econometric models demonstrate that both volumetric and flat rate water charges are strongly and inversely related to agricultural water consumption. Nonprice conservation incentives accompanying flat rates are hypothesized to explain the negative correlation of flat rate charges and water consumption. Application of these results suggests that water supply organizations in the sample population converting to volumetric pricing will generally reduce water consumption.

  3. Volumetric Hall effect tomography--a feasibility study.

    PubMed

    Wen, H

    1999-07-01

    Hall effect imaging is an ultrasound-based method of mapping spatial variations in the dielectric constants of an acoustically-uniform sample. This paper presents three-dimensional Hall effect images of phantoms obtained by scanning a single transducer across a two-dimensional grid, effectively simulating two-dimensional phased-array signal reception. The experiments demonstrate the feasibility of volumetric Hall effect tomography and show the advantage of volumetric scans over planar scans. The images reflect several limitations of the current scanning method and point to directions for further hardware development. The inherent limitations of Hall effect imaging are also discussed in light of these results.

  4. Volumetric particle image velocimetry with a single plenoptic camera

    NASA Astrophysics Data System (ADS)

    Fahringer, Timothy W.; Lynch, Kyle P.; Thurow, Brian S.

    2015-11-01

    A novel three-dimensional (3D), three-component (3C) particle image velocimetry (PIV) technique based on volume illumination and light field imaging with a single plenoptic camera is described. A plenoptic camera uses a densely packed microlens array mounted near a high resolution image sensor to sample the spatial and angular distribution of light collected by the camera. The multiplicative algebraic reconstruction technique (MART) computed tomography algorithm is used to reconstruct a volumetric intensity field from individual snapshots and a cross-correlation algorithm is used to estimate the velocity field from a pair of reconstructed particle volumes. This work provides an introduction to the basic concepts of light field imaging with a plenoptic camera and describes the unique implementation of MART in the context of plenoptic image data for 3D/3C PIV measurements. Simulations of a plenoptic camera using geometric optics are used to generate synthetic plenoptic particle images, which are subsequently used to estimate the quality of particle volume reconstructions at various particle number densities. 3D reconstructions using this method produce reconstructed particles that are elongated by a factor of approximately 4 along the optical axis of the camera. A simulated 3D Gaussian vortex is used to test the capability of single camera plenoptic PIV to produce a 3D/3C vector field, where it was found that lateral displacements could be measured to approximately 0.2 voxel accuracy in the lateral direction and 1 voxel in the depth direction over a 300× 200× 200 voxel volume. The feasibility of the technique is demonstrated experimentally using a home-built plenoptic camera based on a 16-megapixel interline CCD camera and a 289× 193 array of microlenses and a pulsed Nd:YAG laser. 3D/3C measurements were performed in the wake of a low Reynolds number circular cylinder and compared with measurements made using a conventional 2D/2C PIV system. Overall, single camera

  5. Volumetric synthetic aperture imaging with a piezoelectric 2D row-column probe

    NASA Astrophysics Data System (ADS)

    Bouzari, Hamed; Engholm, Mathias; Christiansen, Thomas Lehrmann; Beers, Christopher; Lei, Anders; Stuart, Matthias Bo; Nikolov, Svetoslav Ivanov; Thomsen, Erik Vilain; Jensen, Jørgen Arendt

    2016-04-01

    The synthetic aperture (SA) technique can be used for achieving real-time volumetric ultrasound imaging using 2-D row-column addressed transducers. This paper investigates SA volumetric imaging performance of an in-house prototyped 3 MHz λ/2-pitch 62+62 element piezoelectric 2-D row-column addressed transducer array. Utilizing single element transmit events, a volume rate of 90 Hz down to 14 cm deep is achieved. Data are obtained using the experimental ultrasound scanner SARUS with a 70 MHz sampling frequency and beamformed using a delay-and-sum (DAS) approach. A signal-to-noise ratio of up to 32 dB is measured on the beamformed images of a tissue mimicking phantom with attenuation of 0.5 dB cm-1 MHz-1, from the surface of the probe to the penetration depth of 300λ. Measured lateral resolution as Full-Width-at-Half-Maximum (FWHM) is between 4λ and 10λ for 18% to 65% of the penetration depth from the surface of the probe. The averaged contrast is 13 dB for the same range. The imaging performance assessment results may represent a reference guide for possible applications of such an array in different medical fields.

  6. Non-Sedated Rapid Volumetric Proton Density MRI Predicts Neonatal Brachial Plexus Birth Palsy Functional Outcome.

    PubMed

    Shen, Peter Y; Nidecker, Anna E; Neufeld, Ethan A; Lee, Paul S; James, Michelle A; Bauer, Andrea S

    2017-03-01

    The current prognostic biomarker of functional outcome in brachial plexus birth palsy is serial clinical examination throughout the first 6 months of age. This can delay surgical treatment and prolong parental anxiety in neonates who will recover spontaneously. A potentially superior biomarker is a volumetric proton density MRI performed at clinical presentation and within the first 12 weeks of life, providing a high spatial and contrast resolution examination in 4 minutes. Nine neonates ranging in age from 4 to 9 weeks who presented with brachial plexus birth palsy were enrolled. All subjects underwent non-sedated 3 Tesla MRI with Cube Proton Density MRI sequence at the same time as their initial clinical visit. Serial clinical examinations were conducted at routine 4 week intervals and the functional performance scores were recorded. MRI findings were divided into pre-ganglionic and post-ganglionic injuries and a radiological scoring system (Shriners Radiological Score) was developed for this study. Proton Density MRI was able to differentiate between pre-ganglionic and post-ganglionic injuries. Radiological scores (Shriners Radiological Score) correlated better with functional performance at 6 months of age (P = .022) than the initial clinical examinations (Active Movement Scale P = .213 and Toronto P = .320). Rapid non-sedated volumetric Cube Proton Density MRI protocol performed at initial clinical presentation can accurately grade severity of brachial plexus birth palsy injury and predict functional performance at 6 months of age. Copyright © 2016 by the American Society of Neuroimaging.

  7. Controlling the light distribution through turbid media with wavefront shaping based on volumetric optoacoustic feedback

    NASA Astrophysics Data System (ADS)

    Deán-Ben, X. Luís.; Estrada, Héctor; Özbek, Ali; Razansky, Daniel

    2016-03-01

    Wavefront shaping based on optoacoustic (photoacoustic) feedback has recently emerged as a promising tool to control the light distribution in optically-scattering media. In this approach, the phase of a short-pulsed light beam is spatially-modulated to create constructive light interference (focusing) at specific locations in the speckle pattern of the scattered wavefield. The optoacoustic signals generated by light absorption provide a convenient feedback mechanism to optimize the phase mask of the spatial light modulator in order to achieve the desired light intensity distribution. The optimization procedure can be done by directly considering the acquired signals or the reconstructed images of the light absorption distribution. Recently, our group has introduced a volumetric (three-dimensional) optoacoustic wavefront shaping platform that enables monitoring the distribution of light absorption in an entire volume with frame rates of tens of Hz. With this approach, it is possible to simultaneously control the volumetric light distribution through turbid media. Experiments performed with absorbing microparticles distributed in a three-dimensional region showcase the feasibility of enhancing the light intensity at specific points, where the size of particles is also essential to maximize the signal enhancement. The advantages provided by optoacoustic imaging in terms of spatial and temporal resolution anticipate new capabilities of wavefront shaping techniques in biomedical optics.

  8. Multitracer: a Java-based tool for anatomic delineation of grayscale volumetric images.

    PubMed

    Woods, Roger P

    2003-08-01

    A Java-based tool for delineating anatomic boundaries in 8- and 16- bit grayscale volumetric images is described. Modern features implemented by the tool include the ability to simultaneously view the current cursor position and the previously delineated boundaries on three orthogonal planes, the ability to magnify images during delineation using high-quality interpolation, the ability to encode and save boundaries with subvoxel resolution, and the ability to utilize coregistered images interchangeably during delineation. Additional features facilitate use of the tool in a multiuser, multiplatform environment and provide support for the documentation of anatomic delineation protocols. In addition to providing direct estimates of structure volumes, areas, and lengths, the tool allows contoured boundaries to be exported for more sophisticated analyses. The tool also provides support for manual editing of image volumes to remove confounding structures and for manual correction of image volumes that have been inaccurately edited. In addition to its research utility, the tool also has potential value in education, allowing students to interact with volumetric data and structural boundaries in three dimensions.

  9. Deep learning for automatic localization, identification, and segmentation of vertebral bodies in volumetric MR images

    NASA Astrophysics Data System (ADS)

    Suzani, Amin; Rasoulian, Abtin; Seitel, Alexander; Fels, Sidney; Rohling, Robert N.; Abolmaesumi, Purang

    2015-03-01

    This paper proposes an automatic method for vertebra localization, labeling, and segmentation in multi-slice Magnetic Resonance (MR) images. Prior work in this area on MR images mostly requires user interaction while our method is fully automatic. Cubic intensity-based features are extracted from image voxels. A deep learning approach is used for simultaneous localization and identification of vertebrae. The localized points are refined by local thresholding in the region of the detected vertebral column. Thereafter, a statistical multi-vertebrae model is initialized on the localized vertebrae. An iterative Expectation Maximization technique is used to register the vertebral body of the model to the image edges and obtain a segmentation of the lumbar vertebral bodies. The method is evaluated by applying to nine volumetric MR images of the spine. The results demonstrate 100% vertebra identification and a mean surface error of below 2.8 mm for 3D segmentation. Computation time is less than three minutes per high-resolution volumetric image.

  10. Cellular energy metabolism

    SciTech Connect

    Glaser, M.

    1991-06-01

    Studies have been carried out on adenylate kinase which is an important enzyme in determining the concentrations of the adenine nucleotides. An efficient method has been developed to clone mutant adenylate kinase genes in E. coli. Site-specific mutagenesis of the wild type gene also has been used to obtain forms of adenylate kinase with altered amino acids. The wild type and mutant forms of adenylate kinase have been overexpressed and large quantities were readily isolated. The kinetic and fluorescence properties of the different forms of adenylate kinase were characterized. This has led to a new model for the location of the AMP and ATP bindings sites on the enzyme and a proposal for the mechanism of substrate inhibition. Crystals of the wild type enzyme were obtained that diffract to at least 2.3 {angstrom} resolution. Experiments were also initiated to determine the function of adenylate kinase in vivo. In one set of experiments, E. coli strains with mutations in adenylate kinase showed large changes in cellular nucleotides after reaching the stationary phase in a low phosphate medium. This was caused by selective proteolytic degradation of the mutant adenylate kinase caused by phosphate starvation.

  11. Implementation and characterization of a 320-slice volumetric CT scanner for simulation in radiation oncology.

    PubMed

    Coolens, C; Breen, S; Purdie, T G; Owrangi, A; Publicover, J; Bartolac, S; Jaffray, D A

    2009-11-01

    Effective target definition and broad employment of treatment response assessment with dynamic contrast-enhanced CT in radiation oncology requires increased speed and coverage for use within a single bolus injection. To this end, a novel volumetric CT scanner (Aquilion One, Toshiba, Tochigi Pref., Japan) has been installed at the Princess Margaret Hospital for implementation into routine CT simulation. This technology offers great advantages for anatomical and functional imaging in both scan speed and coverage. The aim of this work is to investigate the system's imaging performance and quality as well as CT quantification accuracy which is important for radiotherapy dose calculations. The 320-slice CT scanner uses a 160 mm wide-area (2D) solid-state detector design which provides the possibility to acquire a volumetric axial length of 160 mm without moving the CT couch. This is referred to as "volume" and can be scanned with a rotation speed of 0.35-3 s. The scanner can also be used as a 64-slice CT scanner and perform conventional (axial) and helical acquisitions with collimation ranges of 1-32 and 16-32 mm, respectively. Commissioning was performed according to AAPM Reports TG 66 and 39 for both helical and volumetric imaging. Defrise and other cone-beam image analysis tests were performed. Overall, the imaging spatial resolution and geometric efficiency (GE) were found to be very good (>10 lp/mm, <1 mm spatial integrity and GE160 mm=85%) and within the AAPM guidelines as well as IEC recommendations. Although there is evidence of some cone-beam artifacts when scanning the Defrise phantom, image quality was found to be good and sufficient for treatment planning (soft tissue noise <10 HU). Measurements of CT number stability and contrast-to-noise values across the volume indicate clinically acceptable scan accuracy even at the field edge. Initial experience with this exciting new technology confirms its accuracy for routine CT simulation within radiation oncology

  12. Implementation and characterization of a 320-slice volumetric CT scanner for simulation in radiation oncology

    SciTech Connect

    Coolens, C.; Breen, S.; Purdie, T. G.; Owrangi, A.; Publicover, J.; Bartolac, S.; Jaffray, D. A.

    2009-11-15

    Purpose: Effective target definition and broad employment of treatment response assessment with dynamic contrast-enhanced CT in radiation oncology requires increased speed and coverage for use within a single bolus injection. To this end, a novel volumetric CT scanner (Aquilion One, Toshiba, Tochigi Pref., Japan) has been installed at the Princess Margaret Hospital for implementation into routine CT simulation. This technology offers great advantages for anatomical and functional imaging in both scan speed and coverage. The aim of this work is to investigate the system's imaging performance and quality as well as CT quantification accuracy which is important for radiotherapy dose calculations. Methods: The 320-slice CT scanner uses a 160 mm wide-area (2D) solid-state detector design which provides the possibility to acquire a volumetric axial length of 160 mm without moving the CT couch. This is referred to as ''volume'' and can be scanned with a rotation speed of 0.35-3 s. The scanner can also be used as a 64-slice CT scanner and perform conventional (axial) and helical acquisitions with collimation ranges of 1-32 and 16-32 mm, respectively. Commissioning was performed according to AAPM Reports TG 66 and 39 for both helical and volumetric imaging. Defrise and other cone-beam image analysis tests were performed. Results: Overall, the imaging spatial resolution and geometric efficiency (GE) were found to be very good (>10 lp/mm, <1 mm spatial integrity and GE{sub 160mm}=85%) and within the AAPM guidelines as well as IEC recommendations. Although there is evidence of some cone-beam artifacts when scanning the Defrise phantom, image quality was found to be good and sufficient for treatment planning (soft tissue noise <10 HU). Measurements of CT number stability and contrast-to-noise values across the volume indicate clinically acceptable scan accuracy even at the field edge. Conclusions: Initial experience with this exciting new technology confirms its accuracy for

  13. Cellular and molecular mechanisms in kidney fibrosis

    PubMed Central

    Duffield, Jeremy S.

    2014-01-01

    Fibrosis is a characteristic feature of all forms of chronic kidney disease. Deposition of pathological matrix in the interstitial space and within the walls of glomerular capillaries as well as the cellular processes resulting in this deposition are increasingly recognized as important factors amplifying kidney injury and accelerating nephron demise. Recent insights into the cellular and molecular mechanisms of fibrogenesis herald the promise of new therapies to slow kidney disease progression. This review focuses on new findings that enhance understanding of cellular and molecular mechanisms of fibrosis, the characteristics of myofibroblasts, their progenitors, and molecular pathways regulating both fibrogenesis and its resolution. PMID:24892703

  14. Obscuring surface anatomy in volumetric imaging data.

    PubMed

    Milchenko, Mikhail; Marcus, Daniel

    2013-01-01

    The identifying or sensitive anatomical features in MR and CT images used in research raise patient privacy concerns when such data are shared. In order to protect human subject privacy, we developed a method of anatomical surface modification and investigated the effects of such modification on image statistics and common neuroimaging processing tools. Common approaches to obscuring facial features typically remove large portions of the voxels. The approach described here focuses on blurring the anatomical surface instead, to avoid impinging on areas of interest and hard edges that can confuse processing tools. The algorithm proceeds by extracting a thin boundary layer containing surface anatomy from a region of interest. This layer is then "stretched" and "flattened" to fit into a thin "box" volume. After smoothing along a plane roughly parallel to anatomy surface, this volume is transformed back onto the boundary layer of the original data. The above method, named normalized anterior filtering, was coded in MATLAB and applied on a number of high resolution MR and CT scans. To test its effect on automated tools, we compared the output of selected common skull stripping and MR gain field correction methods used on unmodified and obscured data. With this paper, we hope to improve the understanding of the effect of surface deformation approaches on the quality of de-identified data and to provide a useful de-identification tool for MR and CT acquisitions.

  15. Influence of pore pressure change on coseismic volumetric strain

    NASA Astrophysics Data System (ADS)

    Wang, Chi-Yuen; Barbour, Andrew J.

    2017-10-01

    Coseismic strain is fundamentally important for understanding crustal response to changes of stress after earthquakes. The elastic dislocation model has been widely applied to interpreting observed shear deformation caused by earthquakes. The application of the same theory to interpreting volumetric strain, however, has met with difficulty, especially in the far field of earthquakes. Predicted volumetric strain with dislocation model often differs substantially, and sometimes of opposite signs, from observed coseismic volumetric strains. The disagreement suggests that some processes unaccounted for by the dislocation model may occur during earthquakes. Several hypotheses have been suggested, but none have been tested quantitatively. In this paper we first examine published data to highlight the difference between the measured and calculated static coseismic volumetric strains; we then use these data to provide quantitative test of the model that the disagreement may be explained by the change of pore pressure in the shallow crust. The test allows us to conclude that coseismic change of pore pressure may be an important mechanism for coseismic crustal strain and, in the far field, may even be the dominant mechanism. Thus in the interpretation of observed coseismic crustal strain, one needs to account not only for the elastic strain due to fault rupture but also for the strain due to coseismic change of pore pressure.

  16. Space-Time Transfinite Interpolation of Volumetric Material Properties.

    PubMed

    Sanchez, Mathieu; Fryazinov, Oleg; Adzhiev, Valery; Comninos, Peter; Pasko, Alexander

    2015-02-01

    The paper presents a novel technique based on extension of a general mathematical method of transfinite interpolation to solve an actual problem in the context of a heterogeneous volume modelling area. It deals with time-dependent changes to the volumetric material properties (material density, colour, and others) as a transformation of the volumetric material distributions in space-time accompanying geometric shape transformations such as metamorphosis. The main idea is to represent the geometry of both objects by scalar fields with distance properties, to establish in a higher-dimensional space a time gap during which the geometric transformation takes place, and to use these scalar fields to apply the new space-time transfinite interpolation to volumetric material attributes within this time gap. The proposed solution is analytical in its nature, does not require heavy numerical computations and can be used in real-time applications. Applications of this technique also include texturing and displacement mapping of time-variant surfaces, and parametric design of volumetric microstructures.

  17. Combination Gravimetric/Volumetric Sorption Instrument for Energy Applications

    NASA Astrophysics Data System (ADS)

    Bethea, Donald; Burress, Jacob

    The use of gaseous fuels such as hydrogen and methane (natural gas) will reduce emissions. Unfortunately, the storage of hydrogen and methane at room temperature is difficult because they are both supercritical gases, making the adoption of these fuels cumbersome. One means of overcoming the storage problem is to use physisorption-based systems which exploit the van der Waals interaction between the gas and a nanoporous material to compress the gases to near liquid densities. To measure the amount of gas in these materials, gravimetric or volumetric methods are employed. Gravimetric weighs the amount of gas and volumetric uses differences in gas pressures. Gravimetric systems typically have problems with buoyancy corrections. Volumetric systems normally have larger uncertainties that propagate through the isotherm. A modified system will be presented which allows for both gravimetric and volumetric gas sorption measurements. Additionally, the buoyancy corrections for the gravimetric measurements are significantly small and less than the uncertainties in the measurement. This apparatus can take measurements of most gases at room temperature and up to 200 bar.

  18. Video-rate volumetric optical coherence tomography-based microangiography

    NASA Astrophysics Data System (ADS)

    Baran, Utku; Wei, Wei; Xu, Jingjiang; Qi, Xiaoli; Davis, Wyatt O.; Wang, Ruikang K.

    2016-04-01

    Video-rate volumetric optical coherence tomography (vOCT) is relatively young in the field of OCT imaging but has great potential in biomedical applications. Due to the recent development of the MHz range swept laser sources, vOCT has started to gain attention in the community. Here, we report the first in vivo video-rate volumetric OCT-based microangiography (vOMAG) system by integrating an 18-kHz resonant microelectromechanical system (MEMS) mirror with a 1.6-MHz FDML swept source operating at ˜1.3 μm wavelength. Because the MEMS scanner can offer an effective B-frame rate of 36 kHz, we are able to engineer vOMAG with a video rate up to 25 Hz. This system was utilized for real-time volumetric in vivo visualization of cerebral microvasculature in mice. Moreover, we monitored the blood perfusion dynamics during stimulation within mouse ear in vivo. We also discussed this system's limitations. Prospective MEMS-enabled OCT probes with a real-time volumetric functional imaging capability can have a significant impact on endoscopic imaging and image-guided surgery applications.

  19. Uptake and Loss of Carbon Dioxide in Volumetric Analysis.

    ERIC Educational Resources Information Center

    Macca, Carlo

    1986-01-01

    Discusses the use of ratio diagrams, which plot the calculations of equilibrium concentrations of the species of the carbonate system. Provides examples to describe how these diagrams can be used to illustrate the behavior systems of interest in volumetric analysis, where absorption or loss of carbon dioxide takes place. (TW)

  20. VOLUMETRIC LEAK DETECTION IN LARGE UNDERGROUND STORAGE TANKS - VOLUME I

    EPA Science Inventory

    A set of experiments was conducted to determine whether volumetric leak detection system presently used to test underground storage tanks (USTs) up to 38,000 L (10,000 gal) in capacity could meet EPA's regulatory standards for tank tightness and automatic tank gauging systems whe...

  1. Cellular Phone Towers

    MedlinePlus

    ... the call. How are people exposed to the energy from cellular phone towers? As people use cell ... where people can be exposed to them. The energy from a cellular phone tower antenna, like that ...

  2. Volumetric requirements for foam and mist drilling operations

    SciTech Connect

    Okpobiri, G.A.; Ikoku, C.U.

    1986-02-01

    State-of-the-art foam and mist drilling suggests a need for predictive models for volumetric requirements that properly account for frictional losses caused by the solid phase in solids/foam slurry flow, settling velocities of such solids, and pressure drop across bit nozzles during foam flow. The objective of this paper is to fulfill this need. A model that predicts pressure drop across bit nozzles for foam and mist and minimum volumetric requirements for foam and mist drilling operations is presented. It accounts for the compressibility of foam but assumes negligible pressure losses resulting from friction and change in elevation and for the frictional losses caused by the solid phase, pressure drop across bit nozzles, and particle-settling velocity. This technique offers a high degree of flexibility in the selection of wellhead injection pressures and volumetric injection rates. Field application of this work can be accomplished by two primarily graphical methods that depend on compressor specification: variable-backpressure and constant-backpressure schedules. Charts are presented for 7.875- and 9.00-in. hole sizes, and for 0.500-, 0.75-, and 1.00-in. cutting sizes. Penetration rates range from 30 to 90 ft/hr. Results indicate that volumetric requirements increase with increasing hole size, depth, and particle size. Increases in penetration rate cause only minor increases in volumetric requirements. All foam-drilling and well-cleanout operations can be accomplished within the laminar flow region with adherence to 0.55 minimum bottomhole and 0.96 maximum annular foam quality. Annular backpressures greater than atmospheric pressure are needed to maintain a bottomhole foam quality of 0.55 or more while reaching reasonable depths. To maintain constant depth as backpressure increases, however, both wellhead injection pressure and gas injection rate must be increased, and liquid flow rate decreased.

  3. Analysis of Changing Swarm Rate using Volumetric Strain

    NASA Astrophysics Data System (ADS)

    Kumazawa, T.; Ogata, Y.; Kimura, K.; Maeda, K.; Kobayashi, A.

    2015-12-01

    Near the eastern coast of Izu peninsula is an active submarine volcanic region in Japan, where magma intrusions have been observed many times. The forecast of earthquake swarm activities and eruptions are serious concern particularly in nearby hot spring resort areas. It is well known that temporal durations of the swarm activities have been correlated with early volumetric strain changes at a certain observation station of about 20 km distance apart. Therefore the Earthquake Research Committee (2010) investigated some empirical statistical relations to predict sizes of the swarm activity. Here we looked at the background seismicity rate changes during these swarm periods using the non-stationary ETAS model (Kumazawa and Ogata, 2013, 2014), and have found the followings. The modified volumetric strain data, by removing the effect of earth tides, precipitation and coseismic jumps, have significantly higher cross-correlations to the estimated background rates of the ETAS model than to the swarm rate-changes. Specifically, the background seismicity rate synchronizes clearer to the strain change by the lags around a half day. These relations suggest an enhanced prediction of earthquakes in this region using volumetric strain measurements. Hence we propose an extended ETAS model where the background rate is modulated by the volumetric strain data. We have also found that the response function to the strain data can be well approximated by an exponential functions with the same decay rate, but that their intersects are inversely proportional to the distances between the volumetric strain-meter and the onset location of the swarm. Our numerical results by the same proposed model show consistent outcomes for the various major swarms in this region.

  4. Hierarchical cellular materials

    SciTech Connect

    Gibson, L.J.

    1991-12-31

    In this paper a method for estimating the contributions of both the composite and the cellular microstructures to the overall material properties and the mechanical efficiency of natural cellular solids will be described. The method will be demonstrated by focusing on the Young`s modulus; similar techniques can be used for other material properties. The results suggest efficient microstructures for engineered cellular materials.

  5. Hierarchical cellular materials

    SciTech Connect

    Gibson, L.J.

    1991-01-01

    In this paper a method for estimating the contributions of both the composite and the cellular microstructures to the overall material properties and the mechanical efficiency of natural cellular solids will be described. The method will be demonstrated by focusing on the Young's modulus; similar techniques can be used for other material properties. The results suggest efficient microstructures for engineered cellular materials.

  6. Imaging Subcellular Dynamics with Fast and Light-Efficient Volumetrically Parallelized Microscopy

    PubMed Central

    Dean, Kevin M.; Roudot, Philippe; Welf, Erik S.; Pohlkamp, Theresa; Garrelts, Gerard; Herz, Joachim; Fiolka, Reto

    2017-01-01

    In fluorescence microscopy, the serial acquisition of 2D images to form a 3D volume limits the maximum imaging speed. This is particularly evident when imaging adherent cells in a light-sheet fluorescence microscopy format, as their elongated morphologies require ~200 image planes per image volume. Here, by illuminating the specimen with three light-sheets, each independently detected, we present a light-efficient, crosstalk free, and volumetrically parallelized 3D microscopy technique that is optimized for high-speed (up to 14 Hz) subcellular (300 nm lateral, 600 nm axial resolution) imaging of adherent cells. We demonstrate 3D imaging of intracellular processes, including cytoskeletal dynamics in single cell migration and collective wound healing for 1500 and 1000 time points, respectively. Further, we capture rapid biological processes, including trafficking of early endosomes with velocities exceeding 10 microns per second and calcium signaling in primary neurons. PMID:28944279

  7. Aberration-free volumetric high-speed imaging of in vivo retina

    PubMed Central

    Hillmann, Dierck; Spahr, Hendrik; Hain, Carola; Sudkamp, Helge; Franke, Gesa; Pfäffle, Clara; Winter, Christian; Hüttmann, Gereon

    2016-01-01

    Certain topics in research and advancements in medical diagnostics may benefit from improved temporal and spatial resolution during non-invasive optical imaging of living tissue. However, so far no imaging technique can generate entirely diffraction-limited tomographic volumes with a single data acquisition, if the target moves or changes rapidly, such as the human retina. Additionally, the presence of aberrations may represent further difficulties. We show that a simple interferometric setup–based on parallelized optical coherence tomography–acquires volumetric data with 10 billion voxels per second, exceeding previous imaging speeds by an order of magnitude. This allows us to computationally obtain and correct defocus and aberrations resulting in entirely diffraction-limited volumes. As demonstration, we imaged living human retina with clearly visible nerve fiber layer, small capillary networks, and photoreceptor cells. Furthermore, the technique can also obtain phase-sensitive volumes of other scattering structures at unprecedented acquisition speeds. PMID:27762314

  8. Aberration-free volumetric high-speed imaging of in vivo retina

    NASA Astrophysics Data System (ADS)

    Hillmann, Dierck; Spahr, Hendrik; Hain, Carola; Sudkamp, Helge; Franke, Gesa; Pfäffle, Clara; Winter, Christian; Hüttmann, Gereon

    2016-10-01

    Certain topics in research and advancements in medical diagnostics may benefit from improved temporal and spatial resolution during non-invasive optical imaging of living tissue. However, so far no imaging technique can generate entirely diffraction-limited tomographic volumes with a single data acquisition, if the target moves or changes rapidly, such as the human retina. Additionally, the presence of aberrations may represent further difficulties. We show that a simple interferometric setup–based on parallelized optical coherence tomography–acquires volumetric data with 10 billion voxels per second, exceeding previous imaging speeds by an order of magnitude. This allows us to computationally obtain and correct defocus and aberrations resulting in entirely diffraction-limited volumes. As demonstration, we imaged living human retina with clearly visible nerve fiber layer, small capillary networks, and photoreceptor cells. Furthermore, the technique can also obtain phase-sensitive volumes of other scattering structures at unprecedented acquisition speeds.

  9. Quantification of pulmonary arterial wall distensibility using parameters extracted from volumetric micro-CT images

    NASA Astrophysics Data System (ADS)

    Johnson, Roger H.; Karau, Kelly L.; Molthen, Robert C.; Dawson, Christopher A.

    1999-09-01

    Stiffening, or loss of distensibility, of arterial vessel walls is among the manifestations of a number of vascular diseases including pulmonary arterial hypertension. We are attempting to quantify the mechanical properties of vessel walls of the pulmonary arterial tree using parameters derived from high-resolution volumetric x-ray CT images of rat lungs. The pulmonary arterial trees of the excised lungs are filled with a contrast agent. The lungs are imaged with arterial pressures spanning the physiological range. Vessel segment diameters are measured from the inlet to the periphery, and distensibilities calculated from diameters as a function of pressure. The method shows promise as an adjunct to other morphometric techniques such as histology and corrosion casting. It possesses the advantages of being nondestructive, characterizing the vascular structures while the lungs are imaged rapidly and in a near-physiological state, and providing the ability to associate mechanical properties with vessel location in the intact tree hierarchy.

  10. An Approach to Extract Moving Objects from Mls Data Using a Volumetric Background Representation

    NASA Astrophysics Data System (ADS)

    Gehrung, J.; Hebel, M.; Arens, M.; Stilla, U.

    2017-05-01

    Data recorded by mobile LiDAR systems (MLS) can be used for the generation and refinement of city models or for the automatic detection of long-term changes in the public road space. Since for this task only static structures are of interest, all mobile objects need to be removed. This work presents a straightforward but powerful approach to remove the subclass of moving objects. A probabilistic volumetric representation is utilized to separate MLS measurements recorded by a Velodyne HDL-64E into mobile objects and static background. The method was subjected to a quantitative and a qualitative examination using multiple datasets recorded by a mobile mapping platform. The results show that depending on the chosen octree resolution 87-95% of the measurements are labeled correctly.

  11. Impact of Reduced k-Space Acquisition on Pathologic Detectability for Volumetric MR Spectroscopic Imaging

    PubMed Central

    Sabati, Mohammad; Zhan, Jiping; Govind, Varan; Arheart, Kristopher L.; Maudsley, Andrew A.

    2013-01-01

    Purpose To assess the impact of accelerated acquisitions on the spectral quality of volumetric MR spectroscopic imaging (MRSI) and to evaluate their ability in detecting metabolic changes with mild injury. Materials and Methods The implementation of a generalized autocalibrating partially parallel acquisition (GRAPPA) method for a high-resolution whole-brain echo planar SI (EPSI) sequence is first described and the spectral accuracy of the GRAPPA-EPSI method is investigated using lobar and voxel-based analyses for normal subjects and patients with mild traumatic brain injuries (mTBI). The performance of GRAPPA was compared with that of fully-encoded EPSI for 5 datasets collected from normal subjects at the same scanning session, as well as on 45 scans (20 normal subjects and 25 mTBI patients) for which the reduced k-space sampling was simulated. For comparison, a central k-space lower-resolution 3D-EPSI acquisition was also simulated. Differences in individual metabolites and metabolite ratio distributions of the mTBI group relative to those of age-matched control subjects were statistically evaluated using analyses divided into hemispheric brain lobes and tissue types. Results GRAPPA-EPSI with 16-min scan time yielded robust and similar results in terms of MRSI quantitation, spectral fitting, and accuracy with that of fully sampled 3D-EPSI acquisitions and was more accurate than central k-space acquisition. Primary findings included high correlations (accuracy of 92.6%) between the GRAPPA and fully sampled results. Conclusion Although the reduced encoding method is associated with lower SNR that impact the quality of spectral analysis the use of parallel imaging method can lead to same diagnostic outcomes as of the fully sampled data when using the sensitivity-limited volumetric MRSI. PMID:23559504

  12. Accuracy of model-based tracking of knee kinematics and cartilage contact measured by dynamic volumetric MRI.

    PubMed

    Kaiser, Jarred; Monawer, Arezu; Chaudhary, Rajeev; Johnson, Kevin M; Wieben, Oliver; Kijowski, Richard; Thelen, Darryl G

    2016-10-01

    The purpose of this study was to determine the accuracy of knee kinematics and cartilage contact measured by volumetric dynamic MRI. A motor-actuated phantom drove femoral and tibial bone segments through cyclic 3D motion patterns. Volumetric images were continuously acquired using a 3D radially undersampled cine spoiled gradient echo sequence (SPGR-VIPR). Image data was binned based on position measured via a MRI-compatible rotary encoder. High-resolution static images were segmented to create bone models. Model-based tracking was performed by optimally registering the bone models to the volumetric images at each frame of the SPGR-VIPR series. 3D tibiofemoral translations and orientations were reconstructed, and compared to kinematics obtained by tracking fiducial markers. Imaging was repeated on a healthy subject who performed cyclic knee flexion-extension. Cartilage contact for the subject was assessed by measuring the overlap between articular cartilage surfaces. Model-based tracking was able to track tibiofemoral angles and translations with precisions less than 0.8° and 0.5mm. These precisions resulted in an uncertainty of less than 0.5mm in cartilage contact location. Dynamic SPGR-VIPR imaging can accurately assess in vivo knee kinematics and cartilage contact during voluntary knee motion performed in a MRI scanner. This technology could facilitate the quantitative investigation of links between joint mechanics and the development of osteoarthritis.

  13. In vivo label-free measurement of lymph flow velocity and volumetric flow rates using Doppler optical coherence tomography

    PubMed Central

    Blatter, Cedric; Meijer, Eelco F. J.; Nam, Ahhyun S.; Jones, Dennis; Bouma, Brett E.; Padera, Timothy P.; Vakoc, Benjamin J.

    2016-01-01

    Direct in vivo imaging of lymph flow is key to understanding lymphatic system function in normal and disease states. Optical microscopy techniques provide the resolution required for these measurements, but existing optical techniques for measuring lymph flow require complex protocols and provide limited temporal resolution. Here, we describe a Doppler optical coherence tomography platform that allows direct, label-free quantification of lymph velocity and volumetric flow rates. We overcome the challenge of very low scattering by employing a Doppler algorithm that operates on low signal-to-noise measurements. We show that this technique can measure lymph velocity at sufficiently high temporal resolution to resolve the dynamic pulsatile flow in collecting lymphatic vessels. PMID:27377852

  14. In vivo label-free measurement of lymph flow velocity and volumetric flow rates using Doppler optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Blatter, Cedric; Meijer, Eelco F. J.; Nam, Ahhyun S.; Jones, Dennis; Bouma, Brett E.; Padera, Timothy P.; Vakoc, Benjamin J.

    2016-07-01

    Direct in vivo imaging of lymph flow is key to understanding lymphatic system function in normal and disease states. Optical microscopy techniques provide the resolution required for these measurements, but existing optical techniques for measuring lymph flow require complex protocols and provide limited temporal resolution. Here, we describe a Doppler optical coherence tomography platform that allows direct, label-free quantification of lymph velocity and volumetric flow rates. We overcome the challenge of very low scattering by employing a Doppler algorithm that operates on low signal-to-noise measurements. We show that this technique can measure lymph velocity at sufficiently high temporal resolution to resolve the dynamic pulsatile flow in collecting lymphatic vessels.

  15. Volumetric index of Tl-201 uptake in symptomatic patients after high - dose radiation treatment for high-grade gliomas

    SciTech Connect

    Carvalho, P.A.; Garada, B.M.; Loeffler, J.S. |

    1995-05-01

    To verify the utility of a volumetric estimation of Tl-201 uptake in the context of possible astrocytoma recurrence after surgery, radiotherapy plus stereotactic boost (radiosurgery/brachitherapy), we analyzed sequential Tl-201/Tc99m-HMPAO brain SPECT studies of 28 patients (18 m/10 f). These were categorized as having tumor mass recurrence (TM), infiltrating tumor cells but no definite tumor mass (IT), or radiation changes and necrosis (RCN) after stereotactic biopsy and/or craniotomy. SPECT studies were obtained with a high-resolution dedicated gamma camera (CERASPECT, Digital Scinitgraphics, Inc.) and image acquisition was performed after intravenous Tl-201 (18.5 MBq) and Tc-99m HMPAO (740 MBq). In order to include relevant information about tumor burden, a volumetric index of Tl-201 uptake was expressed in cm{sup 3} related to voxel size (4.6 x 10{sup -3} cc) within an elliptical ROI that included the tumor area. Only voxels with a threshold {ge} 2 in relation to the average scalp Tl-201 uptake were included and this total number of voxels expressed in cc was compared to previously established maximal tumor/scalp Tl-201 uptake ratios (T/S) and histopathology. Results are presented as the median (min-max) and differences were considered significant for p<0.05. Differences were significant between all groups for both ratios and volume indices and correlation between the two variables was 0.90. In conclusion, the volumetric index of Tl-201 is similar to the maximal Tl-201 T/S ratios in discriminating tumor recurrence and radiation necrosis, suggesting a future role for the volumetric index estimation in the evaluation of treatment efficacy and patient follow-up.

  16. Initialization of a Numerical Mesoscale Model with ALEXI-derived Volumetric Soil Moisture: Case Results and Validation

    NASA Astrophysics Data System (ADS)

    Mecikalski, J. R.; Hain, C. R.; Anderson, M. C.

    2006-05-01

    Soil moisture plays a vital role in the portioning of sensible and latent heat fluxes in the surface energy budget, although high spatial-resolution observations of it are quite rare. The ALEXI model contains the two-source land-surface representation of Norman et al. (1995), which partitions surface fluxes and radiometric temperature into canopy and soil contributions based on the fraction of vegetation cover within the scene. Anderson et al. (1997) and Mecikalski (1999) detail the implementation of ALEXI as a regional-scale application over the continental United States. This model relies on remote sensing data to operate, including GOES-derived surface brightness temperature changes, AVHRR-derived land cover properties, as well as synoptic weather data to operate (Mecikalski, 1999). This version of the ALEXI algorithm has been run daily on a 10 km resolution grid from the years 2002 to present. ALEXI diagnoses a fraction of potential evapotranspiration (fPET) for both the surface layer (0-5 cm) and root-zone (5-200 cm), given a calculation of the potential ET for each pixel. In current mesoscale modeling the fraction of potential ET can be directly related to a fraction of available water, which in turn can be used to calculate volumetric soil moisture for a given soil texture. Soil moisture conditions of the surface and root-zone yield a distinctive thermal signature, where moisture deficiency will lead to surfaces warming more quickly. Current land-surface models (LDAS, NLDAS) such as those used in the North American Mesoscale Model (NAM) use antecedent precipitation as the primary component to the calculation of volumetric soil moisture. These models use four layers in their soil model (0-10, 10-40, 40-100, and 100-200 cm), while ALEXI provides derived volumetric soil moisture for only two layers within the 0-200 cm depth. This discrepancy can be solved with a blending of the two layers from ALEXI to provide a reasonable representation of the observed

  17. A quality assurance phantom for the performance evaluation of volumetric micro-CT systems

    NASA Astrophysics Data System (ADS)

    Du, Louise Y.; Umoh, Joseph; Nikolov, Hristo N.; Pollmann, Steven I.; Lee, Ting-Yim; Holdsworth, David W.

    2007-12-01

    Small-animal imaging has recently become an area of increased interest because more human diseases can be modeled in transgenic and knockout rodents. As a result, micro-computed tomography (micro-CT) systems are becoming more common in research laboratories, due to their ability to achieve spatial resolution as high as 10 µm, giving highly detailed anatomical information. Most recently, a volumetric cone-beam micro-CT system using a flat-panel detector (eXplore Ultra, GE Healthcare, London, ON) has been developed that combines the high resolution of micro-CT and the fast scanning speed of clinical CT, so that dynamic perfusion imaging can be performed in mice and rats, providing functional physiological information in addition to anatomical information. This and other commercially available micro-CT systems all promise to deliver precise and accurate high-resolution measurements in small animals. However, no comprehensive quality assurance phantom has been developed to evaluate the performance of these micro-CT systems on a routine basis. We have designed and fabricated a single comprehensive device for the purpose of performance evaluation of micro-CT systems. This quality assurance phantom was applied to assess multiple image-quality parameters of a current flat-panel cone-beam micro-CT system accurately and quantitatively, in terms of spatial resolution, geometric accuracy, CT number accuracy, linearity, noise and image uniformity. Our investigations show that 3D images can be obtained with a limiting spatial resolution of 2.5 mm-1 and noise of ±35 HU, using an acquisition interval of 8 s at an entrance dose of 6.4 cGy.

  18. A quality assurance phantom for the performance evaluation of volumetric micro-CT systems.

    PubMed

    Du, Louise Y; Umoh, Joseph; Nikolov, Hristo N; Pollmann, Steven I; Lee, Ting-Yim; Holdsworth, David W

    2007-12-07

    Small-animal imaging has recently become an area of increased interest because more human diseases can be modeled in transgenic and knockout rodents. As a result, micro-computed tomography (micro-CT) systems are becoming more common in research laboratories, due to their ability to achieve spatial resolution as high as 10 microm, giving highly detailed anatomical information. Most recently, a volumetric cone-beam micro-CT system using a flat-panel detector (eXplore Ultra, GE Healthcare, London, ON) has been developed that combines the high resolution of micro-CT and the fast scanning speed of clinical CT, so that dynamic perfusion imaging can be performed in mice and rats, providing functional physiological information in addition to anatomical information. This and other commercially available micro-CT systems all promise to deliver precise and accurate high-resolution measurements in small animals. However, no comprehensive quality assurance phantom has been developed to evaluate the performance of these micro-CT systems on a routine basis. We have designed and fabricated a single comprehensive device for the purpose of performance evaluation of micro-CT systems. This quality assurance phantom was applied to assess multiple image-quality parameters of a current flat-panel cone-beam micro-CT system accurately and quantitatively, in terms of spatial resolution, geometric accuracy, CT number accuracy, linearity, noise and image uniformity. Our investigations show that 3D images can be obtained with a limiting spatial resolution of 2.5 mm(-1) and noise of +/-35 HU, using an acquisition interval of 8 s at an entrance dose of 6.4 cGy.

  19. Volumetric characterization of delamination fields via angle longitudinal wave ultrasound

    NASA Astrophysics Data System (ADS)

    Wertz, John; Wallentine, Sarah; Welter, John; Dierken, Josiah; Aldrin, John

    2017-02-01

    The volumetric characterization of delaminations necessarily precedes rigorous composite damage progression modeling. Yet, inspection of composite structures for subsurface damage remains largely focused on detection, resulting in a capability gap. In response to this need, angle longitudinal wave ultrasound was employed to characterize a composite surrogate containing a simulated three-dimensional delamination field with distinct regions of occluded features (shadow regions). Simple analytical models of the specimen were developed to guide subsequent experimentation through identification of optimal scanning parameters. The ensuing experiments provided visual evidence of the complete delamination field, including indications of features within the shadow regions. The results of this study demonstrate proof-of-principle for the use of angle longitudinal wave ultrasonic inspection for volumetric characterization of three-dimensional delamination fields. Furthermore, the techniques developed herein form the foundation of succeeding efforts to characterize impact delaminations within inhomogeneous laminar materials such as polymer matrix composites.

  20. Volumetric hydrogen storage in single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Liu, C.; Yang, Q. H.; Tong, Y.; Cong, H. T.; Cheng, H. M.

    2002-04-01

    Macroscopically long ropes of aligned single-walled carbon nanotubes (SWNTs), synthesized by a hydrogen and argon arc discharge method, were cold pressed into tablets without any binder for measurements of their volumetric hydrogen storage capacity. The typical apparent density of the tablets was measured to be around 1.7 g/cm3 with respect to a molding pressure of 0.75 Gpa. A volumetric and mass hydrogen storage capacity of 68 kg H2/m3 and 4.0 wt %, respectively, was achieved at room temperature under a pressure of 11 MPa for suitably pretreated SWNT tablets, and more than 70% of the hydrogen adsorbed can be released under ambient pressure at room temperature. Pore structure analysis indicated that the molding process diminished the mesopore volume of the SWNT ropes, but exerts little influence on their intrinsic pore textures.

  1. COMPARISON OF VOLUMETRIC REGISTRATION ALGORITHMS FOR TENSOR-BASED MORPHOMETRY

    PubMed Central

    Villalon, Julio; Joshi, Anand A.; Toga, Arthur W.; Thompson, Paul M.

    2015-01-01

    Nonlinear registration of brain MRI scans is often used to quantify morphological differences associated with disease or genetic factors. Recently, surface-guided fully 3D volumetric registrations have been developed that combine intensity-guided volume registrations with cortical surface constraints. In this paper, we compare one such algorithm to two popular high-dimensional volumetric registration methods: large-deformation viscous fluid registration, formulated in a Riemannian framework, and the diffeomorphic “Demons” algorithm. We performed an objective morphometric comparison, by using a large MRI dataset from 340 young adult twin subjects to examine 3D patterns of correlations in anatomical volumes. Surface-constrained volume registration gave greater effect sizes for detecting morphometric associations near the cortex, while the other two approaches gave greater effects sizes subcortically. These findings suggest novel ways to combine the advantages of multiple methods in the future. PMID:26925198

  2. High volumetric power density, non-enzymatic, glucose fuel cells.

    PubMed

    Oncescu, Vlad; Erickson, David

    2013-01-01

    The development of new implantable medical devices has been limited in the past by slow advances in lithium battery technology. Non-enzymatic glucose fuel cells are promising replacement candidates for lithium batteries because of good long-term stability and adequate power density. The devices developed to date however use an "oxygen depletion design" whereby the electrodes are stacked on top of each other leading to low volumetric power density and complicated fabrication protocols. Here we have developed a novel single-layer fuel cell with good performance (2 μW cm⁻²) and stability that can be integrated directly as a coating layer on large implantable devices, or stacked to obtain a high volumetric power density (over 16 μW cm⁻³). This represents the first demonstration of a low volume non-enzymatic fuel cell stack with high power density, greatly increasing the range of applications for non-enzymatic glucose fuel cells.

  3. A method to detect landmark pairs accurately between intra-patient volumetric medical images.

    PubMed

    Yang, Deshan; Zhang, Miao; Chang, Xiao; Fu, Yabo; Liu, Shi; Li, Harold H; Mutic, Sasa; Duan, Ye

    2017-08-23

    An image processing procedure was developed in this study to detect large quantity of landmark pairs accurately in pairs of volumetric medical images. The detected landmark pairs can be used to evaluate of deformable image registration (DIR) methods quantitatively. Landmark detection and pair matching were implemented in a Gaussian pyramid multi-resolution scheme. A 3D scale-invariant feature transform (SIFT) feature detection method and a 3D Harris-Laplacian corner detection method were employed to detect feature points, i.e., landmarks. A novel feature matching algorithm, Multi-Resolution Inverse-Consistent Guided Matching or MRICGM, was developed to allow accurate feature pairs matching. MRICGM performs feature matching using guidance by the feature pairs detected at the lower resolution stage and the higher confidence feature pairs already detected at the same resolution stage, while enforces inverse consistency. The proposed feature detection and feature pair matching algorithms were optimized to process 3D CT and MRI images. They were successfully applied between the inter-phase abdomen 4DCT images of three patients, between the original and the re-scanned radiation therapy simulation CT images of two head-neck patients, and between inter-fractional treatment MRIs of two patients. The proposed procedure was able to successfully detect and match over 6300 feature pairs on average. The automatically detected landmark pairs were manually verified and the mismatched pairs were rejected. The automatic feature matching accuracy before manual error rejection was 99.4%. Performance of MRICGM was also evaluated using seven digital phantom datasets with known ground truth of tissue deformation. On average, 11855 feature pairs were detected per digital phantom dataset with TRE = 0.77 ± 0.72 mm. A procedure was developed in this study to detect large number of landmark pairs accurately between two volumetric medical images. It allows a semi-automatic way to generate the

  4. Volumetric 3D display using a DLP projection engine

    NASA Astrophysics Data System (ADS)

    Geng, Jason

    2012-03-01

    In this article, we describe a volumetric 3D display system based on the high speed DLPTM (Digital Light Processing) projection engine. Existing two-dimensional (2D) flat screen displays often lead to ambiguity and confusion in high-dimensional data/graphics presentation due to lack of true depth cues. Even with the help of powerful 3D rendering software, three-dimensional (3D) objects displayed on a 2D flat screen may still fail to provide spatial relationship or depth information correctly and effectively. Essentially, 2D displays have to rely upon capability of human brain to piece together a 3D representation from 2D images. Despite the impressive mental capability of human visual system, its visual perception is not reliable if certain depth cues are missing. In contrast, volumetric 3D display technologies to be discussed in this article are capable of displaying 3D volumetric images in true 3D space. Each "voxel" on a 3D image (analogous to a pixel in 2D image) locates physically at the spatial position where it is supposed to be, and emits light from that position toward omni-directions to form a real 3D image in 3D space. Such a volumetric 3D display provides both physiological depth cues and psychological depth cues to human visual system to truthfully perceive 3D objects. It yields a realistic spatial representation of 3D objects and simplifies our understanding to the complexity of 3D objects and spatial relationship among them.

  5. Inorganic volumetric light source excited by ultraviolet light

    DOEpatents

    Reed, S.; Walko, R.J.; Ashley, C.S.; Brinker, C.J.

    1994-04-26

    The invention relates to a composition for the volumetric generation of radiation. The composition comprises a porous substrate loaded with a component capable of emitting radiation upon interaction with an exciting radiation. Preferably, the composition is an aerogel substrate loaded with a component, e.g., a phosphor, capable of interacting with exciting radiation of a first energy, e.g., ultraviolet light, to produce radiation of a second energy, e.g., visible light. 4 figures.

  6. Inorganic volumetric light source excited by ultraviolet light

    DOEpatents

    Reed, Scott; Walko, Robert J.; Ashley, Carol S.; Brinker, C. Jeffrey

    1994-01-01

    The invention relates to a composition for the volumetric generation of radiation. The composition comprises a porous substrate loaded with a component capable of emitting radiation upon interaction with an exciting radiation. Preferably, the composition is an aerogel substrate loaded with a component, e.g., a phosphor, capable of interacting with exciting radiation of a first energy, e.g., ultraviolet light, to produce radiation of a second energy, e.g., visible light.

  7. Determining the volumetric steam content in a BWR gravity leg

    SciTech Connect

    Fedulin, V.N.; Bartolomei, G.G.; Solodkii, V.A.; Shmelev, V.E.

    1987-09-01

    The structure of two-phase flow in a large-diameter limited-height gravity leg was investigated in the VK-50 reactor. Phase distribution properties and a physical model of the steam-water mixture flow in the gravity leg were described. On the basis of experimentally derived date a method was proposed for the calculation of volumetric steam content in the leg.

  8. A Cellular Biophysics Textbook

    NASA Astrophysics Data System (ADS)

    Wilder, Alan Joseph

    2011-12-01

    In the past two decades, great advances have been made in understanding of the biophysical mechanisms of the protein machines that carry out the fundamental processes of the cell. It is now known that all major eukaryotic cellular processes require a complicated assemblage of proteins acting via a series of concerted motions. In order to grasp current understanding of cellular mechanisms, the new generation of cell biologists needs to be trained in the general characteristics of these cellular properties and the methods with which to study them. This cellular biophysics textbook, to be used in conjunction with the cellular biophysics course (MCB143) at UC-Davis, provides a great tool in the instruction of the new generation of cellular biologists. It provides a hierarchical view of the cell, from atoms to protein machines and explains in depth the mechanisms of cytoskeletal force generators as an example of these principles.

  9. Volumetric Light-field Encryption at the Microscopic Scale

    NASA Astrophysics Data System (ADS)

    Li, Haoyu; Guo, Changliang; Muniraj, Inbarasan; Schroeder, Bryce C.; Sheridan, John T.; Jia, Shu

    2017-01-01

    We report a light-field based method that allows the optical encryption of three-dimensional (3D) volumetric information at the microscopic scale in a single 2D light-field image. The system consists of a microlens array and an array of random phase/amplitude masks. The method utilizes a wave optics model to account for the dominant diffraction effect at this new scale, and the system point-spread function (PSF) serves as the key for encryption and decryption. We successfully developed and demonstrated a deconvolution algorithm to retrieve both spatially multiplexed discrete data and continuous volumetric data from 2D light-field images. Showing that the method is practical for data transmission and storage, we obtained a faithful reconstruction of the 3D volumetric information from a digital copy of the encrypted light-field image. The method represents a new level of optical encryption, paving the way for broad industrial and biomedical applications in processing and securing 3D data at the microscopic scale.

  10. Volumetric Echocardiographic Particle Image Velocimetry (V-Echo-PIV)

    NASA Astrophysics Data System (ADS)

    Falahatpisheh, Ahmad; Kheradvar, Arash

    2015-11-01

    Measurement of 3D flow field inside the cardiac chambers has proven to be a challenging task. Current laser-based 3D PIV methods estimate the third component of the velocity rather than directly measuring it and also cannot be used to image the opaque heart chambers. Modern echocardiography systems are equipped with 3D probes that enable imaging the entire 3D opaque field. However, this feature has not yet been employed for 3D vector characterization of blood flow. For the first time, we introduce a method that generates velocity vector field in 4D based on volumetric echocardiographic images. By assuming the conservation of brightness in 3D, blood speckles are tracked. A hierarchical 3D PIV method is used to account for large particle displacement. The discretized brightness transport equation is solved in a least square sense in interrogation windows of size 163 voxels. We successfully validate the method in analytical and experimental cases. Volumetric echo data of a left ventricle is then processed in the systolic phase. The expected velocity fields were successfully predicted by V-Echo-PIV. In this work, we showed a method to image blood flow in 3D based on volumetric images of human heart using no contrast agent.

  11. Volumetric Light-field Encryption at the Microscopic Scale

    PubMed Central

    Li, Haoyu; Guo, Changliang; Muniraj, Inbarasan; Schroeder, Bryce C.; Sheridan, John T.; Jia, Shu

    2017-01-01

    We report a light-field based method that allows the optical encryption of three-dimensional (3D) volumetric information at the microscopic scale in a single 2D light-field image. The system consists of a microlens array and an array of random phase/amplitude masks. The method utilizes a wave optics model to account for the dominant diffraction effect at this new scale, and the system point-spread function (PSF) serves as the key for encryption and decryption. We successfully developed and demonstrated a deconvolution algorithm to retrieve both spatially multiplexed discrete data and continuous volumetric data from 2D light-field images. Showing that the method is practical for data transmission and storage, we obtained a faithful reconstruction of the 3D volumetric information from a digital copy of the encrypted light-field image. The method represents a new level of optical encryption, paving the way for broad industrial and biomedical applications in processing and securing 3D data at the microscopic scale. PMID:28059149

  12. Innovative system architecture for spatial volumetric acoustic seeing

    NASA Astrophysics Data System (ADS)

    Levin, Eugene; Sergeyev, Aleksandr V.

    2009-04-01

    Situational awareness is a critical issue for the modern battle and security systems improvement of which will increase human performance efficiency. There are multiple research project and development efforts based on omni-directional (fish-eye) electro-optical and other frequency sensor fusion systems implementing head-mounted visualization systems. However, the efficiency of these systems is limited by the human eye-brain system perception limitations. Humans are capable to naturally perceive the situations in front of them, but interpretation of omni-directional visual scenes increases the user's mental workload, increasing human fatigue and disorientation requiring more effort for object recognition. It is especially important to reduce this workload making rear scenes perception intuitive in battlefield situations where a combatant can be attacked from both directions. This paper describes an experimental model of the system fusion architecture of the Visual Acoustic Seeing (VAS) for representation spatial geometric 3D model in form of 3D volumetric sound. Current research in the area of auralization points to the possibility of identifying sound direction. However, for complete spatial perception it is necessary to identify the direction and the distance to an object by an expression of volumetric sound, we initially assume that the distance can be encoded by the sound frequency. The chain: object features -> sensor -> 3D geometric model-> auralization constitutes Volumetric Acoustic Seeing (VAS). Paper describes VAS experimental research for representing and perceiving spatial information by means of human hearing cues in more details.

  13. Volumetric requirements for foam and mist drilling operations

    SciTech Connect

    Okpobiri, G.A.; Ikoku, C.U.

    1983-03-01

    The present state of the art in foam and mist drilling suggests a need for predictive models for volumetric requirements that properly account for frictional losses due to the solid phase in solidsfoam slurry flow, settling velocities of such solids, and pressure drop across bit nozzles during foam flow. The objective of this paper is to fulfill this need. A model for predicting pressure drop across bit nozzles for foam and mist is presented. It accounts for the compressibility of foam, but assumes negligible pressure losses due to friction and change in elevation. A model has been developed for predicting minimum volumetric requirements for foam and mist drilling operations. It accounts for the frictional losses due to the solid phase, pressure drop across bit nozzles, and particle settling velocity. The technique offers a high degree of flexibility in the selection of wellhead injection pressures and volumetric injection rates. Field application of this work can be accomplished by two methods depending on compressor specifications. These are the ''variable back pressure'' and ''constant back pressure'' schedules. These are primarily graphical. Charts are presented for 7.875 and 9.00-inch hole sizes, and cuttings sizes of 0.500, 0.75, and 1.00 inch. Penetration rates range from 30 to 90 ft/hr.

  14. Reducing uncertainties in volumetric image based deformable organ registration.

    PubMed

    Liang, J; Yan, D

    2003-08-01

    Applying volumetric image feedback in radiotherapy requires image based deformable organ registration. The foundation of this registration is the ability of tracking subvolume displacement in organs of interest. Subvolume displacement can be calculated by applying biomechanics model and the finite element method to human organs manifested on the multiple volumetric images. The calculation accuracy, however, is highly dependent on the determination of the corresponding organ boundary points. Lacking sufficient information for such determination, uncertainties are inevitable-thus diminishing the registration accuracy. In this paper, a method of consuming energy minimization was developed to reduce these uncertainties. Starting from an initial selection of organ boundary point correspondence on volumetric image sets, the subvolume displacement and stress distribution of the whole organ are calculated and the consumed energy due to the subvolume displacements is computed accordingly. The corresponding positions of the initially selected boundary points are then iteratively optimized to minimize the consuming energy under geometry and stress constraints. In this study, a rectal wall delineated from patient CT image was artificially deformed using a computer simulation and utilized to test the optimization. Subvolume displacements calculated based on the optimized boundary point correspondence were compared to the true displacements, and the calculation accuracy was thereby evaluated. Results demonstrate that a significant improvement on the accuracy of the deformable organ registration can be achieved by applying the consuming energy minimization in the organ deformation calculation.

  15. Quality Multi-domain Meshing for Volumetric Data

    PubMed Central

    Zhang, Qin; Subramanian, Bharadwaj; Xu, Guoliang; Bajaj, Chandrajit L.

    2011-01-01

    Multi-domain meshing from volumetric data is of great importance in many fields like medicine, biology and geology. This paper proposes a new approach to produce a high quality mesh with separated multiple domains. A point cloud is generated from a preliminary mesh representing the boundary between different domains from the discrete volumetric representation used as input. A higher-order level-set method is employed to produce a quality sub-mesh from this point cloud and geometric flow is used as smoothing mechanism. A new approach to detect and curate intersections within an assembly of these 2-manifold sub-meshes by utilizing the intermediate volumetric representation is developed. The separation between sub-meshes can be controlled by the user using a gap threshold parameter. The resulting high quality multi-domain mesh is free from self- and inter-domain intersections and can be further utilized in finite element and boundary element computations. The proposed pipeline has been efficiently implemented and sample meshes have been provided for visualization. PMID:21544233

  16. Volumetric Light-field Encryption at the Microscopic Scale.

    PubMed

    Li, Haoyu; Guo, Changliang; Muniraj, Inbarasan; Schroeder, Bryce C; Sheridan, John T; Jia, Shu

    2017-01-06

    We report a light-field based method that allows the optical encryption of three-dimensional (3D) volumetric information at the microscopic scale in a single 2D light-field image. The system consists of a microlens array and an array of random phase/amplitude masks. The method utilizes a wave optics model to account for the dominant diffraction effect at this new scale, and the system point-spread function (PSF) serves as the key for encryption and decryption. We successfully developed and demonstrated a deconvolution algorithm to retrieve both spatially multiplexed discrete data and continuous volumetric data from 2D light-field images. Showing that the method is practical for data transmission and storage, we obtained a faithful reconstruction of the 3D volumetric information from a digital copy of the encrypted light-field image. The method represents a new level of optical encryption, paving the way for broad industrial and biomedical applications in processing and securing 3D data at the microscopic scale.

  17. Volumetric characterization of sodium-induced G-quadruplex formation.

    PubMed

    Fan, Helen Y; Shek, Yuen Lai; Amiri, Amir; Dubins, David N; Heerklotz, Heiko; Macgregor, Robert B; Chalikian, Tigran V

    2011-03-30

    Oligodeoxyribonucleotides (ODN) with repeats of the human telomeric sequence can adopt different tetrahelical conformations that exhibit similar energetic parameters. We studied the volumetric properties of the folded and unfolded states of an ODN with four repeats of the human telomeric sequence, d[A(GGGTTA)(3)GGG], by combining pressure-perturbation calorimetry (PPC), vibrating tube densimetry, ultrasonic velocimetry, and UV melting under high pressure. We carried out our volumetric measurements in aqueous buffers at pH 7 containing 20, 50, and 100 mM NaCl. All of the methods employed yielded volumetric parameters that were in excellent agreement. The molar volume changes, ΔV, of the conformational transition leading to formation of the folded state are large and positive. At 50 mM NaCl, the average transition volume, ΔV(tr), obtained from all the methods is 56.4 ± 3.5 cm(3) mol(-1) at the transition temperature of 47 °C, with ΔV(tr) decreasing with an increase in temperature. We carried out a molecular dynamics simulation of the change in the intrinsic geometric parameters of the ODN accompanying quadruplex formation. On the basis of the experimental and computational results, the folding transition of the ODN is accompanied by a release of 103 ± 44 water molecules from its hydration shell to the bulk. This number corresponds to ~18% of the net hydration of the coil conformation.

  18. Volumetric lattice Boltzmann simulation for blood flow in aorta arteries

    NASA Astrophysics Data System (ADS)

    Deep, Debanjan; Yu, Huidan (Whitney); Teague, Shawn

    2012-11-01

    Complicated moving boundaries pose a major challenge in computational fluid dynamics for complex flows, especially in the biomechanics of both blood flow in the cardiovascular system and air flow in the respiratory system where the compliant nature of the vessels can have significant effects on the flow rate and wall shear stress. We develop a computation approach to treat arbitrarily moving boundaries using a volumetric representation of lattice Boltzmann method, which distributes fluid particles inside lattice cells. A volumetric bounce-back procedure is applied in the streaming step while momentum exchange between the fluid and moving solid boundary are accounted for in the collision sub-step. Additional boundary-induced migration is introduced to conserve fluid mass as the boundary moves across fluid cells. The volumetric LBM (VLBM) is used to simulate blood flow in both normal and dilated aorta arteries. We first compare flow structure and pressure distribution in steady state with results from Navier-Stokes based solver and good agreements are achieved. Then we focus on wall stress within the aorta for different heart pumping condition and present quantitative measurement of wall shear and normal stress.

  19. Automatic high-resolution infarct detection using volumetric multiphase dual-energy CT.

    PubMed

    Sandfort, Veit; Kwan, Alan C; Elumogo, Comfort; Vigneault, Davis M; Symons, Rolf; Pourmorteza, Amir; Rice, Kelly; Davies-Venn, Cynthia; Ahlman, Mark A; Liu, Chia-Ying; Zimmerman, Stefan L; Bluemke, David A

    Late contrast enhancement CT (LCE-CT) visualizes the presence of myocardial infarcts. Differentiation of the contrast-enhanced infarct from blood pool is challenging. We developed a novel method using data from first pass CT angiography (CTA) imaging to enable automatic infarct detection. A canine model of myocardial infarction was produced in 11 animals. Two months later, first pass CTA (90 kVp) and LCE-CT (dual energy 90 kVp/150 kVp tin filtered) were performed. Late gadolinium enhancement MRI was used as reference standard. The CTA and LCE-CT were co-registered using a fully automatic non-rigid method based on curved B-splines. The method allowed for limited elastic deformation and the considerable differences in attenuation between first-pass and delayed image. The blood pool was easily identified on the CTA image by high attenuation. Because CTA and LCE-CT were registered, the blood pool segmentation can be directly transferred to the LCE-CT - thereby solving the key problem of infarct/blood pool differentiation. The remaining segmentation of infarcted vs. noninfarcted myocardium was performed using a threshold. Automatic and MRI-guided expert segmentations of LCE-CT infarcts were compared to each other on volume and area basis (intraclass correlation coefficient, ICC) and on voxel basis (dice similarity coefficient, DSC between automatic and expert CT segmentation). CT infarct volumes were compared with the reference standard MRI. The infarcts were mainly subendocardial (81%) and relatively small (median MRI infarct mass 7.4 g). The automatic segmentation showed excellent agreement with expert segmentation on volume and area measurements (ICC = 0.96 and 0.87, respectively). DSC showed moderately good agreement (DSC = 0.47). Compared to MRI there was modest agreement (ICC = 0.62) and excellent correlation (R = 0.9). Manual interaction was less than 1 min per exam. We propose an automatic method for infarct segmentation on LCE-CT using multiphase CT information, which showed excellent agreement with expert readers and favorable correlation with MRI. Published by Elsevier Inc.

  20. A Nanocrystal Sensor for Luminescence Detection of Cellular Forces

    SciTech Connect

    Choi, Charina; Chou, Jonathan; Lutker, Katie; Werb, Zena; Alivisatos, Paul

    2011-09-29

    Quantum dots have been used as bright fluorescent tags with high photostability to probe numerous biological systems. In this work we present the tetrapod quantum dot as a dynamic, next-generation nanocrystal probe that fluorescently reports cellular forces with spatial and temporal resolution. Its small size and colloidal state suggest that the tetrapod may be further developed as a tool to measure cellular forces in vivo and with macromolecular spatial resolution.

  1. Cell biology of the future: Nanometer-scale cellular cartography.

    PubMed

    Taraska, Justin W

    2015-10-26

    Understanding cellular structure is key to understanding cellular regulation. New developments in super-resolution fluorescence imaging, electron microscopy, and quantitative image analysis methods are now providing some of the first three-dimensional dynamic maps of biomolecules at the nanometer scale. These new maps--comprehensive nanometer-scale cellular cartographies--will reveal how the molecular organization of cells influences their diverse and changeable activities.

  2. Ultrahigh Resolution Optical Coherence Tomography

    NASA Astrophysics Data System (ADS)

    Drexler, Wolfgang; Chen, Yu; Aguirre, Aaron D.; Považay, Boris; Unterhuber, Angelika; Fujimoto, James G.

    Since its invention in the late 1980s [1-4] and early 1990s [5-7], the original idea of OCT was to enable noninvasive optical biopsy, i.e., the in situ imaging of tissue microstructure with a resolution approaching that of histology, but without the need for tissue excision and post-processing. An important advance toward this goal was the introduction of ultrahigh-resolution OCT (UHR OCT). By improving axial OCT resolution by one order of magnitude from the 10 to 15 μm to the sub-μm region [8-11], UHR OCT enables superior visualization of tissue microstructure, including all major intraretinal layers in ophthalmic applications as well as cellular resolution OCT imaging in nontransparent tissue. This chapter reviews state-of-the-art technology that enables ultrahigh-resolution OCT covering the entire wavelength region from 500 to 1,600 nm and discusses fundamental limitations of OCT image resolution.

  3. Modelling cellular behaviour

    NASA Astrophysics Data System (ADS)

    Endy, Drew; Brent, Roger

    2001-01-01

    Representations of cellular processes that can be used to compute their future behaviour would be of general scientific and practical value. But past attempts to construct such representations have been disappointing. This is now changing. Increases in biological understanding combined with advances in computational methods and in computer power make it possible to foresee construction of useful and predictive simulations of cellular processes.

  4. Brain volumetric abnormalities in patients with anorexia and bulimia nervosa: a voxel-based morphometry study.

    PubMed

    Amianto, Federico; Caroppo, Paola; D'Agata, Federico; Spalatro, Angela; Lavagnino, Luca; Caglio, Marcella; Righi, Dorico; Bergui, Mauro; Abbate-Daga, Giovanni; Rigardetto, Roberto; Mortara, Paolo; Fassino, Secondo

    2013-09-30

    Recent studies focussing on neuroimaging features of eating disorders have observed that anorexia nervosa (AN) is characterized by significant grey matter (GM) atrophy in many brain regions, especially in the cerebellum and anterior cingulate cortex. To date, no studies have found GM atrophy in bulimia nervosa (BN) or have directly compared patients with AN and BN. We used voxel-based morphometry (VBM) to characterize brain abnormalities in AN and BN patients, comparing them with each other and with a control group, and correlating brain volume with clinical features. We recruited 17 AN, 13 BN and 14 healthy controls. All subjects underwent high-resolution magnetic resonance imaging (MRI) with a T1-weighted 3D image. VBM analysis was carried out with the FSL-VBM 4.1 tool. We found no global atrophy, but regional GM reduction in AN with respect to controls and BN in the cerebellum, fusiform area, supplementary motor area, and occipital cortex, and in the caudate in BN compared to AN and controls. Both groups of patients had a volumetric increase bilaterally in somatosensory regions with respect to controls, in areas that are typically involved in the sensory-motor integration of body stimuli and in mental representation of the body image. Our VBM study documented, for the first time in BN patients, the presence of volumetric alterations and replicated previous findings in AN patients. We evidenced morphological differences between AN and BN, demonstrating in the latter atrophy of the caudate nucleus, a region involved in reward mechanisms and processes of self-regulation, perhaps involved in the genesis of the binge-eating behaviors of this disorder. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  5. Flat-panel volumetric computed tomography in cerebral perfusion: evaluation of three rat stroke models.

    PubMed

    Juenemann, Martin; Goegel, Sinja; Obert, Martin; Schleicher, Nadine; Ritschel, Nouha; Doenges, Simone; Eitenmueller, Inka; Schwarz, Niko; Kastaun, Sabrina; Yeniguen, Mesut; Tschernatsch, Marlene; Gerriets, Tibo

    2013-09-30

    Flat-panel volumetric computed tomography (fpVCT) is a non-invasive approach to three-dimensional small animal imaging. The capability of volumetric scanning and a high resolution in time and space enables whole organ perfusion studies. We aimed to assess feasibility and validity of fpVCT in cerebral perfusion measurement with impaired hemodynamics by evaluation of three well-established rat stroke models for temporary and permanent middle cerebral artery occlusion (MCAO). Male Wistar rats were randomly assigned to temporary (group I: suture model) and permanent (group II: suture model; III: macrosphere model) MCAO and to a control group. Perfusion scans with respect to cerebral blood flow (CBF) and volume (CBV) were performed 24h post intervention by fpVCT, using a Gantry rotation time of 1s and a total scanning time of 30s. Postmortem analysis included infarct-size calculation by 2,3,5-triphenyltetrazolium chloride (TTC) staining. Infarct volumes did not differ significantly throughout intervention groups. After permanent MCAO, CBF significantly decreased in subcortical regions to 78.2% (group II, p=0.005) and 79.9% (group III, p=0.012) and in total hemisphere to 77.4% (group II, p=0.010) and 82.0% (group III, p=0.049). CBF was less impaired with temporary vessel occlusion. CBV measurement revealed no significant differences. Results demonstrate feasibility of cerebral perfusion quantification in rats with the fpVCT, which can be a useful tool for non-invasive dynamic imaging of cerebral perfusion in rodent stroke models. In addition to methodological advantages, CBF data confirm the macrosphere model as a useful alternative to the suture model for permanent experimental MCAO.

  6. Radiological determination of the posterior limits of the temporal lobe for volumetric analysis.

    PubMed

    Doherty, C P; Meredith, G E; Farrell, M; Toland, J; Staunton, H

    1999-04-01

    The posterior peri-Sylvian area is the most highly lateralized part of the human brain due to its specialised role in language. Currently, there is no clearly defined posterior boundary of the temporal lobe which takes account of language lateralization and which can be reliably determined radiologically. However, there have been a number of recent advances in magnetic resonance technology including volume visualisation techniques which have as their goal the realistic three-dimensional representation of the brain which is acquired in two-dimensional slices. These have enabled the identification of precise macroanatomical and cytoarchitectural boundaries from which an efficient and reproducible posterior limit may be demarcated. Such limit standardisation is important for volumetric investigations of both neurological and psychiatric disease. Magnetic resonance imaging (MRI) scans of 20 normal subjects (10 male and 10 female), aged between 18 and 42 years, were acquired as part of a study of normal temporal lobe volume variation. In order to demonstrate the method of posterior limit placement, a thin slice (1.5 mm) 3D spoiled gradient magnetic resonance image of the brain of a 30 year-old right-handed male, without neurological disease, was acquired on a 1.5 tesla GE magnetic resonance machine. The data set was transferred via network to the hard disk of a 166 MHz Pentium processor PC. A software package called MEASURE allowed reformation of the data set in all three orthogonal planes. Then, using a high resolution algorithm, the brain was aligned along the newly proposed posterior plane which runs from the limit of the Sylvian fissure, identified on a 3D rendering, to the posterior/inferior splenium. It is hoped that this procedure will be utilised as a standard method for radiological determination of the limit of the posterior temporal lobe in order to allow volumetric measurements of this structure to be compared in a meaningful way.

  7. Image quality assessment of a pre-clinical flat-panel volumetric micro-CT scanner

    NASA Astrophysics Data System (ADS)

    Du, Louise Y.; Lee, Ting-Yim; Holdsworth, David W.

    2006-03-01

    Small animal imaging has recently become an area of increased interest because more human diseases can be modeled in transgenic and knockout rodents. Current micro-CT systems are capable of achieving spatial resolution on the order of 10 μm, giving highly detailed anatomical information. However, the speed of data acquisition of these systems is relatively slow, when compared with clinical CT systems. Dynamic CT perfusion imaging has proven to be a powerful tool clinically in detecting and diagnosing cancer, stroke, pulmonary and ischemic heart diseases. In order to perform this technique in mice and rats, quantitative CT images must be acquired at a rate of at least 1 Hz. Recently, a research pre-clinical CT scanner (eXplore Ultra, GE Healthcare) has been designed specifically for dynamic perfusion imaging in small animals. Using an amorphous silicon flat-panel detector and a clinical slip-ring gantry, this system is capable of acquiring volumetric image data at a rate of 1 Hz, with in-plane resolution of 150 μm, while covering the entire thoracic region of a mouse or whole organs of a rat. The purpose of this study was to evaluate the principal imaging performance of the micro-CT system, in terms of spatial resolution, image uniformity, linearity, dose and voxel noise for the feasibility of imaging mice and rats. Our investigations show that 3D images can be obtained with a limiting spatial resolution of 2.7 line pairs per mm and noise of 42 HU, using an acquisition interval of 8 seconds at an entrance dose of 6.4 cGy.

  8. Volumetric CT with sparse detector arrays (and application to Si-strip photon counters)

    NASA Astrophysics Data System (ADS)

    Sisniega, A.; Zbijewski, W.; Stayman, J. W.; Xu, J.; Taguchi, K.; Fredenberg, E.; Lundqvist, Mats; Siewerdsen, J. H.

    2016-01-01

    Novel x-ray medical imaging sensors, such as photon counting detectors (PCDs) and large area CCD and CMOS cameras can involve irregular and/or sparse sampling of the detector plane. Application of such detectors to CT involves undersampling that is markedly different from the commonly considered case of sparse angular sampling. This work investigates volumetric sampling in CT systems incorporating sparsely sampled detectors with axial and helical scan orbits and evaluates performance of model-based image reconstruction (MBIR) with spatially varying regularization in mitigating artifacts due to sparse detector sampling. Volumetric metrics of sampling density and uniformity were introduced. Penalized-likelihood MBIR with a spatially varying penalty that homogenized resolution by accounting for variations in local sampling density (i.e. detector gaps) was evaluated. The proposed methodology was tested in simulations and on an imaging bench based on a Si-strip PCD (total area 5 cm  ×  25 cm) consisting of an arrangement of line sensors separated by gaps of up to 2.5 mm. The bench was equipped with translation/rotation stages allowing a variety of scanning trajectories, ranging from a simple axial acquisition to helical scans with variable pitch. Statistical (spherical clutter) and anthropomorphic (hand) phantoms were considered. Image quality was compared to that obtained with a conventional uniform penalty in terms of structural similarity index (SSIM), image uniformity, spatial resolution, contrast, and noise. Scan trajectories with intermediate helical width (~10 mm longitudinal distance per 360° rotation) demonstrated optimal tradeoff between the average sampling density and the homogeneity of sampling throughout the volume. For a scan trajectory with 10.8 mm helical width, the spatially varying penalty resulted in significant visual reduction of sampling artifacts, confirmed by a 10% reduction in minimum SSIM (from 0.88 to 0.8) and a 40

  9. Volumetric CT with sparse detector arrays (and application to Si-strip photon counters)

    PubMed Central

    Sisniega, A; Zbijewski, W; Stayman, J W; Xu, J; Taguchi, K; Fredenberg, E; Lundqvist, Mats; Siewerdsen, J H

    2016-01-01

    Novel x-ray medical imaging sensors, such as photon counting detectors (PCDs) and large area CCD and CMOS cameras can involve irregular and/or sparse sampling of the detector plane. Application of such detectors to CT involves undersampling that is markedly different from the commonly considered case of sparse angular sampling. This work investigates volumetric sampling in CT systems incorporating sparsely sampled detectors with axial and helical scan orbits and evaluates performance of model-based image reconstruction (MBIR) with spatially varying regularization in mitigating artifacts due to sparse detector sampling. Volumetric metrics of sampling density and uniformity were introduced. Penalized-likelihood MBIR with a spatially varying penalty that homogenized resolution by accounting for variations in local sampling density (i.e. detector gaps) was evaluated. The proposed methodology was tested in simulations and on an imaging bench based on a Si-strip PCD (total area 5 cm × 25 cm) consisting of an arrangement of line sensors separated by gaps of up to 2.5 mm. The bench was equipped with translation/rotation stages allowing a variety of scanning trajectories, ranging from a simple axial acquisition to helical scans with variable pitch. Statistical (spherical clutter) and anthropomorphic (hand) phantoms were considered. Image quality was compared to that obtained with a conventional uniform penalty in terms of structural similarity index (SSIM), image uniformity, spatial resolution, contrast, and noise. Scan trajectories with intermediate helical width (~10 mm longitudinal distance per 360° rotation) demonstrated optimal tradeoff between the average sampling density and the homogeneity of sampling throughout the volume. For a scan trajectory with 10.8 mm helical width, the spatially varying penalty resulted in significant visual reduction of sampling artifacts, confirmed by a 10% reduction in minimum SSIM (from 0.88 to 0.8) and a 40% reduction in the

  10. Volumetric CT with sparse detector arrays (and application to Si-strip photon counters).

    PubMed

    Sisniega, A; Zbijewski, W; Stayman, J W; Xu, J; Taguchi, K; Fredenberg, E; Lundqvist, Mats; Siewerdsen, J H

    2016-01-07

    Novel x-ray medical imaging sensors, such as photon counting detectors (PCDs) and large area CCD and CMOS cameras can involve irregular and/or sparse sampling of the detector plane. Application of such detectors to CT involves undersampling that is markedly different from the commonly considered case of sparse angular sampling. This work investigates volumetric sampling in CT systems incorporating sparsely sampled detectors with axial and helical scan orbits and evaluates performance of model-based image reconstruction (MBIR) with spatially varying regularization in mitigating artifacts due to sparse detector sampling. Volumetric metrics of sampling density and uniformity were introduced. Penalized-likelihood MBIR with a spatially varying penalty that homogenized resolution by accounting for variations in local sampling density (i.e. detector gaps) was evaluated. The proposed methodology was tested in simulations and on an imaging bench based on a Si-strip PCD (total area 5 cm  ×  25 cm) consisting of an arrangement of line sensors separated by gaps of up to 2.5 mm. The bench was equipped with translation/rotation stages allowing a variety of scanning trajectories, ranging from a simple axial acquisition to helical scans with variable pitch. Statistical (spherical clutter) and anthropomorphic (hand) phantoms were considered. Image quality was compared to that obtained with a conventional uniform penalty in terms of structural similarity index (SSIM), image uniformity, spatial resolution, contrast, and noise. Scan trajectories with intermediate helical width (~10 mm longitudinal distance per 360° rotation) demonstrated optimal tradeoff between the average sampling density and the homogeneity of sampling throughout the volume. For a scan trajectory with 10.8 mm helical width, the spatially varying penalty resulted in significant visual reduction of sampling artifacts, confirmed by a 10% reduction in minimum SSIM (from 0.88 to 0.8) and a 40

  11. Fast volumetric calcium imaging across multiple cortical layers using sculpted light.

    PubMed

    Prevedel, Robert; Verhoef, Aart J; Pernía-Andrade, Alejandro J; Weisenburger, Siegfried; Huang, Ben S; Nöbauer, Tobias; Fernández, Alma; Delcour, Jeroen E; Golshani, Peyman; Baltuska, Andrius; Vaziri, Alipasha

    2016-12-01

    Although whole-organism calcium imaging in small and semi-transparent animals has been demonstrated, capturing the functional dynamics of large-scale neuronal circuits in awake behaving mammals at high speed and resolution has remained one of the main frontiers in systems neuroscience. Here we present a method based on light sculpting that enables unbiased single- and dual-plane high-speed (up to 160 Hz) calcium imaging as well as in vivo volumetric calcium imaging of a mouse cortical column (0.5 mm × 0.5 mm × 0.5 mm) at single-cell resolution and fast volume rates (3-6 Hz). We achieved this by tailoring the point-spread function of our microscope to the structures of interest while maximizing the signal-to-noise ratio using a home-built fiber laser amplifier with pulses that are synchronized to the imaging voxel speed. This enabled in vivo recording of calcium dynamics of several thousand neurons across cortical layers and in the hippocampus of awake behaving mice.

  12. Fast volumetric calcium imaging across multiple cortical layers using sculpted light

    PubMed Central

    Prevedel, Robert; Verhoef, Aart J.; Pernia-Andrade, Alejandro J.; Weisenburger, Siegfried; Huang, Ben S.; Nöbauer, Tobias; Fernández, Alma; Delcour, Jeroen E.; Golshani, Peyman; Baltuska, Andrius; Vaziri, Alipasha

    2017-01-01

    While whole-organism calcium imaging in small and semi-transparent animals has been demonstrated, capturing the functional dynamics of large-scale neuronal circuits in awake, behaving mammals at high speed and resolution has remained one of the main frontiers in systems neuroscience. Here we present a novel method based on light sculpting that enables unbiased single and dual-plane high-speed (up to 160 Hz) calcium imaging, as well as in vivo volumetric calcium imaging of a mouse cortical column (0.5 × 0.5 × 0.5 mm) at single-cell resolution and fast volume rates (3 – 6 Hz). This is achieved by tailoring the point-spread function of our microscope to the structures of interest, and by maximizing the signal-to-noise ratio by using a home-built fiber laser amplifier and synchronizing its pulses to the imaging voxel speed. This has enabled in-vivo recording of calcium dynamics of several thousand neurons across cortical layers and in the hippocampus of awake behaving mice. PMID:27798612

  13. Linking Neurons to Network Function and Behavior by Two-Photon Holographic Optogenetics and Volumetric Imaging.

    PubMed

    Dal Maschio, Marco; Donovan, Joseph C; Helmbrecht, Thomas O; Baier, Herwig

    2017-05-17

    We introduce a flexible method for high-resolution interrogation of circuit function, which combines simultaneous 3D two-photon stimulation of multiple targeted neurons, volumetric functional imaging, and quantitative behavioral tracking. This integrated approach was applied to dissect how an ensemble of premotor neurons in the larval zebrafish brain drives a basic motor program, the bending of the tail. We developed an iterative photostimulation strategy to identify minimal subsets of channelrhodopsin (ChR2)-expressing neurons that are sufficient to initiate tail movements. At the same time, the induced network activity was recorded by multiplane GCaMP6 imaging across the brain. From this dataset, we computationally identified activity patterns associated with distinct components of the elicited behavior and characterized the contributions of individual neurons. Using photoactivatable GFP (paGFP), we extended our protocol to visualize single functionally identified neurons and reconstruct their morphologies. Together, this toolkit enables linking behavior to circuit activity with unprecedented resolution. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Cellular Mechanisms of Central Nervous Modulation.

    DTIC Science & Technology

    1983-06-30

    achieve selective disruption of the neuroglia in the central nervous system 4 of our experimental animal, the cockroach (Periplaneta americana). Such...RD-A147 878 CELLULAR MECHANISMIS OF CENTRAL NERVOUS MODULATION(U) i/i I CAMBRIDGE UNIV (ENGLAND) DEPT OF ZOOLOGY J E TRENERNE 30 JUN 83 DHJA37-8i-C...BOOBI UNCLASSFE F/G 6/16 NL bi L& 2. MICROCOPY RESOLUTION TEST CHART NATIONA BUJREAUJ OF STANDOW-S1963-A [.1 PI CELLULAR MECHANISMIS OF CENTRAL NERVOUS

  15. Plasmonic Nanostructured Cellular Automata

    NASA Astrophysics Data System (ADS)

    Alkhazraji, Emad; Ghalib, A.; Manzoor, K.; Alsunaidi, M. A.

    2017-03-01

    In this work, we have investigated the scattering plasmonic resonance characteristics of silver nanospheres with a geometrical distribution that is modelled by Cellular Automata using time-domain numerical analysis. Cellular Automata are discrete mathematical structures that model different natural phenomena. Two binary one-dimensional Cellular Automata rules are considered to model the nanostructure, namely rule 30 and rule 33. The analysis produces three-dimensional scattering profiles of the entire plasmonic nanostructure. For the Cellular Automaton rule 33, the introduction of more Cellular Automata generations resulted only in slight red and blue shifts in the plasmonic modes with respect to the first generation. On the other hand, while rule 30 introduced significant red shifts in the resonance peaks at early generations, at later generations however, a peculiar effect is witnessed in the scattering profile as new peaks emerge as a feature of the overall Cellular Automata structure rather than the sum of the smaller parts that compose it. We strongly believe that these features that emerge as a result adopting the different 256 Cellular Automata rules as configuration models of nanostructures in different applications and systems might possess a great potential in enhancing their capability, sensitivity, efficiency, and power utilization.

  16. Volumetric response of intracranial meningioma after photon or particle irradiation.

    PubMed

    Mozes, Petra; Dittmar, Jan Oliver; Habermehl, Daniel; Tonndorf-Martini, Eric; Hideghety, Katalin; Dittmar, Anne; Debus, Jürgen; Combs, Stephanie E

    2017-03-01

    Meningiomas are usually slow growing, well circumscribed intracranial tumors. In symptom-free cases observation with close follow-up imaging could be performed. Symptomatic meningiomas could be surgically removed and/or treated with radiotherapy. The study aimed to evaluate the volumetric response of intracranial meningiomas at different time points after photon, proton, and a mixed photon and carbon ion boost irradiation. In Group A 38 patients received proton therapy (median dose: 56 GyE in 1.8-2 GyE daily fractions) or a mixed photon/carbon ion therapy (50 Gy in 2 Gy daily fractions with intensity modulated radiotherapy (IMRT) and 18 GyE in 3 GyE daily dose carbon ion boost). Thirty-nine patients (Group B) were treated by photon therapy with IMRT or fractionated stereotactic radiotherapy technique (median dose: 56 Gy in 1.8-2 Gy daily fractions). The delineation of the tumor volume was based on the initial, one- and two-year follow-up magnetic resonance imaging and these volumes were compared to evaluate the volumetric tumor response. Significant tumor volume shrinkage was detected at one- and at two-year follow-up both after irradiation by particles and by photons. No significant difference in tumor volume change was observed between photon, proton or combined photon plus carbon ion boost treated patients. WHO grade and gender appear to be determining factors for tumor volume shrinkage. Significant volumetric shrinkage of meningiomas could be observed independently of the applied radiation modality. Long-term follow-up is recommended to evaluate further dynamic of size reduction and its correlation with outcome data.

  17. Volumetric measurements of pulmonary nodules: variability in automated analysis tools

    NASA Astrophysics Data System (ADS)

    Juluru, Krishna; Kim, Woojin; Boonn, William; King, Tara; Siddiqui, Khan; Siegel, Eliot

    2007-03-01

    Over the past decade, several computerized tools have been developed for detection of lung nodules and for providing volumetric analysis. Incidentally detected lung nodules have traditionally been followed over time by measurements of their axial dimensions on CT scans to ensure stability or document progression. A recently published article by the Fleischner Society offers guidelines on the management of incidentally detected nodules based on size criteria. For this reason, differences in measurements obtained by automated tools from various vendors may have significant implications on management, yet the degree of variability in these measurements is not well understood. The goal of this study is to quantify the differences in nodule maximum diameter and volume among different automated analysis software. Using a dataset of lung scans obtained with both "ultra-low" and conventional doses, we identified a subset of nodules in each of five size-based categories. Using automated analysis tools provided by three different vendors, we obtained size and volumetric measurements on these nodules, and compared these data using descriptive as well as ANOVA and t-test analysis. Results showed significant differences in nodule maximum diameter measurements among the various automated lung nodule analysis tools but no significant differences in nodule volume measurements. These data suggest that when using automated commercial software, volume measurements may be a more reliable marker of tumor progression than maximum diameter. The data also suggest that volumetric nodule measurements may be relatively reproducible among various commercial workstations, in contrast to the variability documented when performing human mark-ups, as is seen in the LIDC (lung imaging database consortium) study.

  18. Volumetric breast density affects performance of digital screening mammography.

    PubMed

    Wanders, Johanna O P; Holland, Katharina; Veldhuis, Wouter B; Mann, Ritse M; Pijnappel, Ruud M; Peeters, Petra H M; van Gils, Carla H; Karssemeijer, Nico

    2017-02-01

    To determine to what extent automatically measured volumetric mammographic density influences screening performance when using digital mammography (DM). We collected a consecutive series of 111,898 DM examinations (2003-2011) from one screening unit of the Dutch biennial screening program (age 50-75 years). Volumetric mammographic density was automatically assessed using Volpara. We determined screening performance measures for four density categories comparable to the American College of Radiology (ACR) breast density categories. Of all the examinations, 21.6% were categorized as density category 1 ('almost entirely fatty') and 41.5, 28.9, and 8.0% as category 2-4 ('extremely dense'), respectively. We identified 667 screen-detected and 234 interval cancers. Interval cancer rates were 0.7, 1.9, 2.9, and 4.4‰ and false positive rates were 11.2, 15.1, 18.2, and 23.8‰ for categories 1-4, respectively (both p-trend < 0.001). The screening sensitivity, calculated as the proportion of screen-detected among the total of screen-detected and interval tumors, was lower in higher density categories: 85.7, 77.6, 69.5, and 61.0% for categories 1-4, respectively (p-trend < 0.001). Volumetric mammographic density, automatically measured on digital mammograms, impacts screening performance measures along the same patterns as established with ACR breast density categories. Since measuring breast density fully automatically has much higher reproducibility than visual assessment, this automatic method could help with implementing density-based supplemental screening.

  19. Synoptic volumetric variations and flushing of the Tampa Bay estuary

    NASA Astrophysics Data System (ADS)

    Wilson, M.; Meyers, S. D.; Luther, M. E.

    2014-03-01

    Two types of analyses are used to investigate the synoptic wind-driven flushing of Tampa Bay in response to the El Niño-Southern Oscillation (ENSO) cycle from 1950 to 2007. Hourly sea level elevations from the St. Petersburg tide gauge, and wind speed and direction from three different sites around Tampa Bay are used for the study. The zonal (u) and meridional (v) wind components are rotated clockwise by 40° to obtain axial and co-axial components according to the layout of the bay. First, we use the subtidal observed water level as a proxy for mean tidal height to estimate the rate of volumetric bay outflow. Second, we use wavelet analysis to bandpass sea level and wind data in the time-frequency domain to isolate the synoptic sea level and surface wind variance. For both analyses the long-term monthly climatology is removed and we focus on the volumetric and wavelet variance anomalies. The overall correlation between the Oceanic Niño Index and volumetric analysis is small due to the seasonal dependence of the ENSO response. The mean monthly climatology between the synoptic wavelet variance of elevation and axial winds are in close agreement. During the winter, El Niño (La Niña) increases (decreases) the synoptic variability, but decreases (increases) it during the summer. The difference in winter El Niño/La Niña wavelet variances is about 20 % of the climatological value, meaning that ENSO can swing the synoptic flushing of the bay by 0.22 bay volumes per month. These changes in circulation associated with synoptic variability have the potential to impact mixing and transport within the bay.

  20. Cellular Reflectarray Antenna

    NASA Technical Reports Server (NTRS)

    Romanofsky, Robert R.

    2010-01-01

    The cellular reflectarray antenna is intended to replace conventional parabolic reflectors that must be physically aligned with a particular satellite in geostationary orbit. These arrays are designed for specified geographical locations, defined by latitude and longitude, each called a "cell." A particular cell occupies nominally 1,500 square miles (3,885 sq. km), but this varies according to latitude and longitude. The cellular reflectarray antenna designed for a particular cell is simply positioned to align with magnetic North, and the antenna surface is level (parallel to the ground). A given cellular reflectarray antenna will not operate in any other cell.

  1. Volumetric (tomographic) three-dimensional geoacoustic inversion in shallow water.

    PubMed

    Tolstoy, A

    2008-11-01

    Geoacoustic inversion is an important but difficult component for shallow water ocean acoustics. There are numerous methods in use to remotely determine bottom and geometric properties in both range-independent and range-dependent situations. While there have been some efforts to combine two-dimensional bottom estimates (range- and depth-dependent inversion slices) calculated around a receiving array into a three-dimensional (range, depth, and azimuthal) image of a region, there is only one approach in existence today, which attempts to determine consistent volumetric bottom properties using multiple arrays and multiple sources. This approach (geoacoustic tomography) will be discussed here (with final improvements via regularization).

  2. Volumetric relief map for intracranial cerebrospinal fluid distribution analysis.

    PubMed

    Lebret, Alain; Kenmochi, Yukiko; Hodel, Jérôme; Rahmouni, Alain; Decq, Philippe; Petit, Éric

    2015-09-01

    Cerebrospinal fluid imaging plays a significant role in the clinical diagnosis of brain disorders, such as hydrocephalus and Alzheimer's disease. While three-dimensional images of cerebrospinal fluid are very detailed, the complex structures they contain can be time-consuming and laborious to interpret. This paper presents a simple technique that represents the intracranial cerebrospinal fluid distribution as a two-dimensional image in such a way that the total fluid volume is preserved. We call this a volumetric relief map, and show its effectiveness in a characterization and analysis of fluid distributions and networks in hydrocephalus patients and healthy adults.

  3. Marginal Space Deep Learning: Efficient Architecture for Volumetric Image Parsing.

    PubMed

    Ghesu, Florin C; Krubasik, Edward; Georgescu, Bogdan; Singh, Vivek; Zheng, Yefeng; Hornegger, Joachim; Comaniciu, Dorin

    2016-03-07

    Robust and fast solutions for anatomical object detection and segmentation support the entire clinical workflow from diagnosis, patient stratification, therapy planning, intervention and follow-up. Current state-of-the-art techniques for parsing volumetric medical image data are typically based on machine learning methods that exploit large annotated image databases. There are two main challenges that need to be addressed, these are the efficiency in processing large volumetric input images and the need for strong, representative image features. When the object of interest is parametrized in a high dimensional space, standard volume scanning techniques do not scale up to the enormous number of potential hypotheses and representative image features are subject to significant efforts of manual engineering. We propose a pipeline for object detection and segmentation in the context of volumetric image parsing, solving a two-step learning problem: anatomical pose estimation and boundary delineation. For this task we introduce Marginal Space Deep Learning (MSDL), a novel framework exploiting both the strengths of efficient object parametrization in hierarchical marginal spaces and the automated feature design of Deep Learning (DL) network architectures. Deep learning systems automatically identify, disentangle and learn explanatory attributes directly from low-level image data, however their application in the volumetric setting is limited by the very high complexity of the parametrization. More specifically 9 parameters are necessary to describe a restricted affine transformation in 3D (3 for each location, orientation, and scale) resulting in a prohibitive number of scanning hypotheses, in the order of billions for typical sampling. The mechanism of marginal space learning provides excellent run-time performance by learning classifiers in clustered, high-probability regions in spaces of gradually increasing dimensionality, for example starting from location only (3D

  4. Prognostic importance of volumetric measurements in stage I lung adenocarcinoma.

    PubMed

    Yanagawa, Masahiro; Tanaka, Yuko; Leung, Ann N; Morii, Eiichi; Kusumoto, Masahiko; Watanabe, Shunichi; Watanabe, Hirokazu; Inoue, Masayoshi; Okumura, Meinoshin; Gyobu, Tomoko; Ueda, Ken; Honda, Osamu; Sumikawa, Hiromitsu; Johkoh, Takeshi; Tomiyama, Noriyuki

    2014-08-01

    To perform volumetric analysis of stage I lung adenocarcinomas by using an automated computer program and to determine value of volumetric computed tomographic (CT) measurements associated with prognostic factors and outcome. Consecutive patients (n = 145) with stage I lung adenocarcinoma who underwent surgery after preoperative chest CT were enrolled. By using volumetric automated computer-assisted analytic program, nodules were classified into three subgroups: pure ground glass, part solid, or solid. Total tumor volume, solid tumor volume, and percentage of solid volume of each cancer were calculated after eliminating vessel components. One radiologist measured the longest diameter of the solid tumor component and of total tumor with their ratio, which was defined as solid proportion. The value of these quantitative data by examining associations with pathologic prognostic factors and outcome measures (disease-free survival and overall survival) were analyzed with logistic regression and Cox proportional hazards regression models, respectively. Significant parameters identified at univariate analysis were included in the multiple analyses. All 22 recurrences occurred in patients with nodules classified as part solid or solid. Multiple logistic regression analysis revealed that percentage of solid volume of 63% or greater was an independent indicator associated with pleural invasion (P = .01). Multiple Cox proportional hazards regression analysis revealed that percentage of solid volume of 63% or greater was a significant indicator of lower disease-free survival (hazard ratio, 18.45 [95% confidence interval: 4.34, 78.49]; P < .001). Both solid tumor volume of 1.5 cm(3) or greater and percentage of solid volume of 63% or greater were significant indicators of decreased overall survival (hazard ratio, 5.92 and 9.60, respectively [95% confidence interval: 1.17, 30.33 and 1.17, 78.91, respectively]; P = .034 and .036, respectively). Two volumetric measurements (solid

  5. Mucosal wrinkling in animal antra induced by volumetric growth

    NASA Astrophysics Data System (ADS)

    Li, Bo; Cao, Yan-Ping; Feng, Xi-Qiao; Yu, Shou-Wen

    2011-04-01

    Surface wrinkling of animal mucosas is crucial for the biological functions of some tissues, and the change in their surface patterns is a phenotypic characteristic of certain diseases. Here we develop a biomechanical model to study the relationship between morphogenesis and volumetric growth, either physiological or pathological, of mucosas. Theoretical analysis and numerical simulations are performed to unravel the critical characteristics of mucosal wrinkling in a spherical antrum. It is shown that the thicknesses and elastic moduli of mucosal and submucosal layers dictate the surface buckling morphology. The results hold clinical relevance for such diseases as inflammation and gastritis.

  6. Novel method for tracking in homogeneous volumetric media

    NASA Astrophysics Data System (ADS)

    Miller, Timothy N.; Butz, John; Milster, Thomas D.; Bletscher, Warren L.; Walker, Edwin P.; Park, Sang-Ki; Felix, David

    2003-09-01

    Volumetric media have great potential for meeting future optical data storage demands, but homogeneous media lack internal features for tracking. A novel method of tracking inside homogeneous media is described that uses external reference tracks attached to the media. Several possible configurations for implementing the "slave-servo" concept are described and compared. An optical design for the most promising configuration is presented. This desing utilizes a diffractive optical element for dispersion compensation. Modeling describes the limits of device performance and alignment. Early prototype results are presented.

  7. Basic Characteristics and Predicted Lifetime of Stacked Volumetric Optical Disks

    NASA Astrophysics Data System (ADS)

    Inaba, Akira; Ido, Hiroshi; Kishi, Hiroyuki; Yamanaka, Hideaki; Osawa, Seigo; Tani, Manabu; Uchida, Takeshi; Watanabe, Yutaka; Arai, Shinichi; Yoshihiro, Masafumi; Iida, Tamotsu; Awano, Hiroyuki; Ota, Norio; Yoshida, Takashi; Abe, Yukinobu; Yoshida, Kazushi

    2008-07-01

    A stacked volumetric optical disks (SVOD) system has been developed to achieve an over 1 Tbytes cartridge capacity using a commercialized drive and conventional recording layers. To confirm the reliability of thin optical disks in SVOD, several feasibility tests were conducted. The recording power margin, tilt margin and read stability of the thin optical disks were measured, and the lifetime of the thin optical disks was estimated. The results were similar to those of conventional 1.2-mm-thick optical disks regardless of the disk thickness.

  8. Synthesis of Volumetric Ring Antenna Array for Terrestrial Coverage Pattern

    PubMed Central

    Reyna, Alberto; Panduro, Marco A.; Del Rio Bocio, Carlos

    2014-01-01

    This paper presents a synthesis of a volumetric ring antenna array for a terrestrial coverage pattern. This synthesis regards the spacing among the rings on the planes X-Y, the positions of the rings on the plane X-Z, and uniform and concentric excitations. The optimization is carried out by implementing the particle swarm optimization. The synthesis is compared with previous designs by resulting with proper performance of this geometry to provide an accurate coverage to be applied in satellite applications with a maximum reduction of the antenna hardware as well as the side lobe level reduction. PMID:24701150

  9. Two-Photon Laser Scanning Stereomicroscopy for Fast Volumetric Imaging

    PubMed Central

    Yang, Yanlong; Yao, Baoli; Lei, Ming; Dan, Dan; Li, Runze; Horn, Mark Van; Chen, Xun; Li, Yang; Ye, Tong

    2016-01-01

    Bessel beams have been successfully used in two-photon laser scanning fluorescence microscopy to extend the depth of field (EDF), which makes it possible to observe fast events volumetrically. However, the depth information is lost due to integration of fluorescence signals along the propagation direction. We describe the design and implementation of two-photon lasers scanning stereomicroscopy, which allows viewing dynamic processes in three-dimensional (3D) space stereoscopically in real-time with shutter glasses at the speed of 1.4 volumes per second. The depth information can be appreciated by human visual system or be recovered with correspondence algorithms for some cases. PMID:27997624

  10. Volumetric hemispheric ratio as a useful tool in personality psychology.

    PubMed

    Montag, Christian; Schoene-Bake, Jan-Christoph; Wagner, Jan; Reuter, Martin; Markett, Sebastian; Weber, Bernd; Quesada, Carlos M

    2013-02-01

    The present study investigates the link between volumetric hemispheric ratios (VHRs) and personality measures in N=267 healthy participants using Eysenck's Personality Inventory-Revised (EPQ-R) and the BIS/BAS scales. A robust association between extraversion and VHRs was observed for gray matter in males but not females. Higher gray matter volume in the left than in the right hemisphere was associated with higher extraversion in males. The results are discussed in the context of positive emotionality and laterality of the human brain.

  11. No volumetric differences in the anterior cingulate of psychopathic individuals

    PubMed Central

    Glenn, Andrea L.; Yang, Yaling; Raine, Adrian; Colletti, Patrick

    2010-01-01

    Functional imaging studies of psychopathy have demonstrated reduced activity in the anterior cingulate, yet it is unclear whether this region is structurally impaired. In this study, we used structural MRI to examine whether volumetric differences exist in the anterior cingulate between psychopathic (n=24) and control (n=24) male participants. We found no group differences in the volume of the anterior cingulate or its dorsal and ventral subregions. Our findings call into question whether the anterior cingulate is impaired in psychopathy, or whether previous findings of reduced activity may result from reduced input from other deficient regions. PMID:20630717

  12. Application of the sonic volumetric scan log to cement evaluation

    SciTech Connect

    Broding, R.A.

    1984-01-01

    The imaging process of a volumetric scan presentation produces a sonic image that gives a pictorial display of the cement in place. The cemented zone can be further evaluated from transmittance and velocity scans. The image can be selected to include the casing to cement bond, the full cemented zone or the cement to formation bond. Sectoring, tilting and rotation of the image allows one to quickly make a first interpretation for any suspect areas. A more detailed study from transmittance and velocity data permits a reliable qualification of the physical properties of the cement in place.

  13. Floating volumetric image formation using a dihedral corner reflector array device.

    PubMed

    Miyazaki, Daisuke; Hirano, Noboru; Maeda, Yuki; Yamamoto, Siori; Mukai, Takaaki; Maekawa, Satoshi

    2013-01-01

    A volumetric display system using an optical imaging device consisting of numerous dihedral corner reflectors placed perpendicular to the surface of a metal plate is proposed. Image formation by the dihedral corner reflector array (DCRA) is free from distortion and focal length. In the proposed volumetric display system, a two-dimensional real image is moved by a mirror scanner to scan a three-dimensional (3D) space. Cross-sectional images of a 3D object are displayed in accordance with the position of the image plane. A volumetric image is observed as a stack of the cross-sectional images. The use of the DCRA brings compact system configuration and volumetric real image generation with very low distortion. An experimental volumetric display system including a DCRA, a galvanometer mirror, and a digital micro-mirror device was constructed to verify the proposed method. A volumetric image consisting of 1024×768×400 voxels was formed by the experimental system.

  14. Electromagnetic cellular interactions.

    PubMed

    Cifra, Michal; Fields, Jeremy Z; Farhadi, Ashkan

    2011-05-01

    Chemical and electrical interaction within and between cells is well established. Just the opposite is true about cellular interactions via other physical fields. The most probable candidate for an other form of cellular interaction is the electromagnetic field. We review theories and experiments on how cells can generate and detect electromagnetic fields generally, and if the cell-generated electromagnetic field can mediate cellular interactions. We do not limit here ourselves to specialized electro-excitable cells. Rather we describe physical processes that are of a more general nature and probably present in almost every type of living cell. The spectral range included is broad; from kHz to the visible part of the electromagnetic spectrum. We show that there is a rather large number of theories on how cells can generate and detect electromagnetic fields and discuss experimental evidence on electromagnetic cellular interactions in the modern scientific literature. Although small, it is continuously accumulating.

  15. Cellular aging and cancer

    PubMed Central

    Hornsby, Peter J.

    2010-01-01

    Aging is manifest in a variety of changes over time, including changes at the cellular level. Cellular aging acts primarily as a tumor suppressor mechanism, but also may enhance cancer development under certain circumstances. One important process of cellular aging is oncogene-induced senescence, which acts as an important anti-cancer mechanism. Cellular senescence resulting from damage caused by activated oncogenes prevents the growth or potentially neoplastic cells. Moreover, cells that have entered senescence appear to be targets for elimination by the innnate immune system. In another aspect of cellular aging, the absence of telomerase activity in normal tissues results in such cells lacking a telomere maintenance mechanism. One consequence is that in aging there is an increase in cells with shortened telomeres. In the presence of active oncogenes that cause expansion of a neoplastic clone, shortening of telomeres leading to telomere dysfunction prevents the indefinite expansion of the clone because the cells enter crisis. Crisis results from fusions and other defects caused by dysfunctional telomeres and is a terminal state of the neoplastic clone. In this way the absence of telomerase in human cells, while one cause of cellular aging, also acts as an anti-cancer mechanism. PMID:20705476

  16. CBCT-based volumetric and dosimetric variation evaluation of volumetric modulated arc radiotherapy in the treatment of nasopharyngeal cancer patients

    PubMed Central

    2013-01-01

    Objective To investigate the anatomic and dosimetric variations of volumetric modulated arc therapy (VMAT) in the treatment of nasopharyngeal cancer (NPC) patients based on weekly cone beam CT (CBCT). Materials and methods Ten NPC patients treated by VMAT with weekly CBCT for setup corrections were reviewed retrospectively. Deformed volumes of targets and organs at risk (OARs) in the CBCT were compared with those in the planning CT. Delivered doses were recalculated based on weekly CBCT and compared with the planned doses. Results No significant volumetric changes on targets, brainstem, and spinal cord were observed. The average volumes of right and left parotid measured from the fifth CBCT were about 4.4 and 4.5 cm3 less than those from the first CBCT, respectively. There were no significant dose differences between average planned and delivered doses for targets, brainstem and spinal cord. For right parotid, the delivered mean dose was 10.5 cGy higher (p = 0.004) than the planned value per fraction, and the V26 and V32 increased by 7.5% (p = 0.002) and 7.4% (p = 0.01), respectively. For the left parotid, the D50 (dose to the 50% volume) was 8.8 cGy higher (p = 0.03) than the planned values per fraction, and the V26 increased by 8.8% (p = 0.002). Conclusion Weekly CBCTs were applied directly to study the continuous volume changes and resulting dosimetric variations of targets and OARs for NPC patients undergoing VMAT. Significant volumetric and dosimetric variations were observed for parotids. Replanning after 30 Gy will benefit the protection on parotids. PMID:24289312

  17. Computational assessment of visual search strategies in volumetric medical images

    PubMed Central

    Wen, Gezheng; Aizenman, Avigael; Drew, Trafton; Wolfe, Jeremy M.; Haygood, Tamara Miner; Markey, Mia K.

    2016-01-01

    Abstract. When searching through volumetric images [e.g., computed tomography (CT)], radiologists appear to use two different search strategies: “drilling” (restrict eye movements to a small region of the image while quickly scrolling through slices), or “scanning” (search over large areas at a given depth before moving on to the next slice). To computationally identify the type of image information that is used in these two strategies, 23 naïve observers were instructed with either “drilling” or “scanning” when searching for target T’s in 20 volumes of faux lung CTs. We computed saliency maps using both classical two-dimensional (2-D) saliency, and a three-dimensional (3-D) dynamic saliency that captures the characteristics of scrolling through slices. Comparing observers’ gaze distributions with the saliency maps showed that search strategy alters the type of saliency that attracts fixations. Drillers’ fixations aligned better with dynamic saliency and scanners with 2-D saliency. The computed saliency was greater for detected targets than for missed targets. Similar results were observed in data from 19 radiologists who searched five stacks of clinical chest CTs for lung nodules. Dynamic saliency may be superior to the 2-D saliency for detecting targets embedded in volumetric images, and thus “drilling” may be more efficient than “scanning.” PMID:26759815

  18. Scanners and drillers: Characterizing expert visual search through volumetric images

    PubMed Central

    Drew, Trafton; Vo, Melissa Le-Hoa; Olwal, Alex; Jacobson, Francine; Seltzer, Steven E.; Wolfe, Jeremy M.

    2013-01-01

    Modern imaging methods like computed tomography (CT) generate 3-D volumes of image data. How do radiologists search through such images? Are certain strategies more efficient? Although there is a large literature devoted to understanding search in 2-D, relatively little is known about search in volumetric space. In recent years, with the ever-increasing popularity of volumetric medical imaging, this question has taken on increased importance as we try to understand, and ultimately reduce, errors in diagnostic radiology. In the current study, we asked 24 radiologists to search chest CTs for lung nodules that could indicate lung cancer. To search, radiologists scrolled up and down through a “stack” of 2-D chest CT “slices.” At each moment, we tracked eye movements in the 2-D image plane and coregistered eye position with the current slice. We used these data to create a 3-D representation of the eye movements through the image volume. Radiologists tended to follow one of two dominant search strategies: “drilling” and “scanning.” Drillers restrict eye movements to a small region of the lung while quickly scrolling through depth. Scanners move more slowly through depth and search an entire level of the lung before moving on to the next level in depth. Driller performance was superior to the scanners on a variety of metrics, including lung nodule detection rate, percentage of the lung covered, and the percentage of search errors where a nodule was never fixated. PMID:23922445

  19. Volumetric Velocity Fields Downstream of a 2-Bladed Turbine

    NASA Astrophysics Data System (ADS)

    Troolin, Daniel

    2013-11-01

    Tip vortices of axial-flow turbines are important in understanding the mean and turbulent characteristics of the wake. Volumetric 3-component velocimetry (V3V) was used to examine the flow downstream of a model two-bladed turbine in air. The turbine had a diameter of 177.8 mm and was powered by a motor operating at approximately 150 rpm. The measurement volume (50 × 50 × 20 mm) was positioned approximately 5 mm downstream of the blade tip, in order to examine the tip vortex structure. The V3V system utilized three 4MP cameras with 85 mm lenses positioned in a fixed triangular frame located at a distance of 450 mm from the back of the measurement volume. The illumination source was a 200 mJ dual-head pulsed Nd:YAG laser operating at 7.25 Hz and illuminating 1 micron olive oil droplets as tracer particles. The particle images were then analyzed to produce volumetric vector fields. The focus was placed on visualizing the complex interaction between the turbine tip vortices. Insights on the tip vortex dynamics and three dimensional characteristics of the wake flow will be discussed.

  20. Photoacoustic analysis of proteins: volumetric signals and fluorescence quantum yields.

    PubMed Central

    Kurian, E; Prendergast, F G; Small, J R

    1997-01-01

    A series of proteins has been examined using time-resolved, pulsed-laser volumetric photoacoustic spectroscopy. Photoacoustic waveforms were collected to measure heat release for calculation of fluorescence quantum yields, and to explore the possibility of photoinduced nonthermal volume changes occurring in these protein samples. The proteins studied were the green fluorescent protein (GFP); intestinal fatty acid binding protein (IFABP), and adipocyte lipid-binding protein (ALBP), each labeled noncovalently with 1-anilinonaphthalene-8-sulfonate (1,8-ANS) and covalently with 6-acryloyl-2-(dimethylamino)naphthalene (acrylodan); and acrylodan-labeled IFABP and ALBP with added oleic acid. Of this group of proteins, only the ALBP labeled with 1,8-ANS showed significant nonthermal volume changes at the beta = 0 temperature (approximately 3.8 degrees C) for the buffer used (10 mM Tris-HCI, pH 7.5) (beta is the thermal cubic volumetric expansion coefficient). For all of the proteins except for acrylodan-labeled IFABP, the fluorescence quantum yields calculated assuming simple energy conservation were anomalously high, i.e., the apparent heat signals were lower than those predicted from independent fluorescence measurements. The consistent anomalies suggest that the low photoacoustic signals may be characteristic of fluorophores buried in proteins, and that photoacoustic signals derive in part from the microenvironment of the absorbing chromophore. Images FIGURE 1 PMID:9199809

  1. Volumetric intraoperative brain deformation compensation: model development and phantom validation.

    PubMed

    DeLorenzo, Christine; Papademetris, Xenophon; Staib, Lawrence H; Vives, Kenneth P; Spencer, Dennis D; Duncan, James S

    2012-08-01

    During neurosurgery, nonrigid brain deformation may affect the reliability of tissue localization based on preoperative images. To provide accurate surgical guidance in these cases, preoperative images must be updated to reflect the intraoperative brain. This can be accomplished by warping these preoperative images using a biomechanical model. Due to the possible complexity of this deformation, intraoperative information is often required to guide the model solution. In this paper, a linear elastic model of the brain is developed to infer volumetric brain deformation associated with measured intraoperative cortical surface displacement. The developed model relies on known material properties of brain tissue, and does not require further knowledge about intraoperative conditions. To provide an initial estimation of volumetric model accuracy, as well as determine the model's sensitivity to the specified material parameters and surface displacements, a realistic brain phantom was developed. Phantom results indicate that the linear elastic model significantly reduced localization error due to brain shift, from > 16 mm to under 5 mm, on average. In addition, though in vivo quantitative validation is necessary, preliminary application of this approach to images acquired during neocortical epilepsy cases confirms the feasibility of applying the developed model to in vivo data.

  2. Investigation of Volumetric Sources in Airframe Noise Simulations

    NASA Technical Reports Server (NTRS)

    Casper, Jay H.; Lockard, David P.; Khorrami, Mehdi R.; Streett, Craig L.

    2004-01-01

    Hybrid methods for the prediction of airframe noise involve a simulation of the near field flow that is used as input to an acoustic propagation formula. The acoustic formulations discussed herein are those based on the Ffowcs Williams and Hawkings equation. Some questions have arisen in the published literature in regard to an apparently significant dependence of radiated noise predictions on the location of the integration surface used in the solution of the Ffowcs Williams and Hawkings equation. These differences in radiated noise levels are most pronounced between solid-body surface integrals and off-body, permeable surface integrals. Such differences suggest that either a non-negligible volumetric source is contributing to the total radiation or the input flow simulation is suspect. The focus of the current work is the issue of internal consistency of the flow calculations that are currently used as input to airframe noise predictions. The case study for this research is a computer simulation for a three-element, high-lift wing profile during landing conditions. The noise radiated from this flow is predicted by a two-dimensional, frequency-domain formulation of the Ffowcs Williams and Hawkings equation. Radiated sound from volumetric sources is assessed by comparison of a permeable surface integration with the sum of a solid-body surface integral and a volume integral. The separate noise predictions are found in good agreement.

  3. Multi-sensor 3D volumetric reconstruction using CUDA

    NASA Astrophysics Data System (ADS)

    Aliakbarpour, Hadi; Almeida, Luis; Menezes, Paulo; Dias, Jorge

    2011-12-01

    This paper presents a full-body volumetric reconstruction of a person in a scene using a sensor network, where some of them can be mobile. The sensor network is comprised of couples of camera and inertial sensor (IS). Taking advantage of IS, the 3D reconstruction is performed using no planar ground assumption. Moreover, IS in each couple is used to define a virtual camera whose image plane is horizontal and aligned with the earth cardinal directions. The IS is furthermore used to define a set of inertial planes in the scene. The image plane of each virtual camera is projected onto this set of parallel-horizontal inertial-planes, using some adapted homography functions. A parallel processing architecture is proposed in order to perform human real-time volumetric reconstruction. The real-time characteristic is obtained by implementing the reconstruction algorithm on a graphics processing unit (GPU) using Compute Unified Device Architecture (CUDA). In order to show the effectiveness of the proposed algorithm, a variety of the gestures of a person acting in the scene is reconstructed and demonstrated. Some analyses have been carried out to measure the performance of the algorithm in terms of processing time. The proposed framework has potential to be used by different applications such as smart-room, human behavior analysis and 3D teleconference. [Figure not available: see fulltext.

  4. Volumetric capnography and chronic obstructive pulmonary disease staging

    PubMed Central

    Romero, Pablo V; Rodriguez, Benigno; de Oliveira, Daniela; Blanch, L; Manresa, Federico

    2007-01-01

    Spirometry is difficult for some COPD patient to perform. Volumetric capnography could be a second choice test to evaluate the severity of functional disturbances. The aim of this work is to test this hypothesis. A total number of 98 subjects were classified either as normal ex-smokers (N = 14) or COPD patients. The latter were staged following GOLD recommendations. Spirometry and volumetric capnography recordings were obtained from each patient. Spirometry parameters, Bohr Dead Space (VD Bohr), Airways Dead Space from the pre-interface expirate corrected curve (VD aw), Phase III slope (SlIII) and Volume of alveolar ejection (VAE) were measured. Index of Ventilatory Efficiency (IVE), and Index of Airways Heterogeneity (IAH) were calculated as: IVE = VAE/(VT – VD aw) and IAH = 1 – [(VT – VD Bohr)/(VT – VD aw)]. In ANOCOVA analysis IAH showed the greatest association with stage (F > 40), with no significant covariant dependence on VT. A receiver operating characteristics curve analysis showed values of the area under the curve greater than 0.9 for IAH and IVE at all stage levels, with a sensitivity = specificity value greater than 80%. We conclude that IAH and IVE can be used when spirometry cannot be reliably performed, as an alternative test to evaluate the degree of functional involvement in COPD patients. PMID:18229577

  5. Scanners and drillers: characterizing expert visual search through volumetric images.

    PubMed

    Drew, Trafton; Vo, Melissa Le-Hoa; Olwal, Alex; Jacobson, Francine; Seltzer, Steven E; Wolfe, Jeremy M

    2013-08-06

    Modern imaging methods like computed tomography (CT) generate 3-D volumes of image data. How do radiologists search through such images? Are certain strategies more efficient? Although there is a large literature devoted to understanding search in 2-D, relatively little is known about search in volumetric space. In recent years, with the ever-increasing popularity of volumetric medical imaging, this question has taken on increased importance as we try to understand, and ultimately reduce, errors in diagnostic radiology. In the current study, we asked 24 radiologists to search chest CTs for lung nodules that could indicate lung cancer. To search, radiologists scrolled up and down through a "stack" of 2-D chest CT "slices." At each moment, we tracked eye movements in the 2-D image plane and coregistered eye position with the current slice. We used these data to create a 3-D representation of the eye movements through the image volume. Radiologists tended to follow one of two dominant search strategies: "drilling" and "scanning." Drillers restrict eye movements to a small region of the lung while quickly scrolling through depth. Scanners move more slowly through depth and search an entire level of the lung before moving on to the next level in depth. Driller performance was superior to the scanners on a variety of metrics, including lung nodule detection rate, percentage of the lung covered, and the percentage of search errors where a nodule was never fixated.

  6. [Benefits of volumetric to facial rejuvenation. Part 1: Fat grafting].

    PubMed

    Bui, P; Lepage, C

    2017-09-05

    For a number of years, a volumetric approach using autologous fat injection has been implemented to improve cosmetic outcome in face-lift procedures and to achieve lasting rejuvenation. Autologous fat as filling tissue has been used in plastic surgery since the late 19th century, but has only recently been associated to face lift procedures. The interest of the association lies on the one hand in the pathophysiology of facial aging, involving skin sag and loss of volume, and on the other hand in the tissue induction properties of grafted fat, "rejuvenating" the injected area. The strict methodology consisting in harvesting, treating then injecting an autologous fat graft is known as LipoStructure(®) or lipofilling. We here describe the technique overall, then region by region. It is now well known and seems simple, effective and reproducible, but is nevertheless delicate. For each individual, it is necessary to restore a harmonious face with well-distributed volumes. By associating volumetric to the face lift procedure, the plastic surgeon plays a new role: instead of being a tailor, cutting away excess skin, he or she becomes a sculptor, remodeling the face to restore the harmony of youth. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  7. Evolution of a turbulent jet subjected to volumetric heating

    NASA Astrophysics Data System (ADS)

    Agrawal, Amit; Prasad, Ajay K.

    2004-07-01

    The goal of this study is to understand the effect of latent heat release on entrainment in cumulus clouds by employing a laboratory analogue consisting of a volumetrically heated turbulent axisymmetric jet. The jet fluid is volumetrically heated in an off-source manner to simulate condensation heat release in clouds. The experimental set-up is similar to Bhat & Narasimha (1996), and the current application of wholefield velocimetry and thermometry has allowed us to probe in detail the velocity and temperature fields within the heat injection zone (HIZ) for the first time, leading to several new results. We are able to demarcate three distinct zones within the HIZ based primarily on the nature of the cross-stream velocity profile, and we present sharp differences in flow properties in these zones. Thermochromic liquid crystal-based temperature visualizations have revealed details about the complex interplay of velocity, local concentration and temperature leading to a physically coherent understanding of this flow. We also provide evidence using linear stochastic estimates (LSE) to show that large eddies are disrupted in the latter part of the HIZ; the disruption of large eddies is linked to the change in the nature of the cross-stream velocity profile. While our results have confirmed certain previously reported observations such as a reduction in scalar width, we have measured significantly larger r.m.s. values within the HIZ than previously reported, which is corroborated by direct numerical simulation results.

  8. Volumetric Flow Measurement Using an Implantable CMUT Array.

    PubMed

    Mengli Wang; Jingkuang Chen

    2011-06-01

    This paper describes volumetric-flow velocity measurement using an implantable capacitive micromachined ultrasonic transducer (CMUT) array. The array is comprised of multiple-concentric CMUT rings for ultrasound transmission and an outmost annular CMUT array for ultrasound reception. Microelectromechanical-system (MEMS) fabrication technology allows reception CMUT on this flowmeter to be implemented with a different membrane thickness and gap height than that of transmission CMUTs, optimizing the performance of these two different kinds of devices. The silicon substrate of this 2-mm-diameter CMUT ring array was bulk micromachined to approximately 80 to 100 μm thick, minimizing tissue disruption. The blood-flow velocity was detected using pulse ultrasound Doppler by comparing the demodulated echo ultrasound with the incident ultrasound. The demodulated ultrasound signal was sampled by a pulse delayed in time domain from the transmitted burst, which corresponds to detecting the signal at a specific distance. The flow tube/vessel diameter was detected through the time-flight delay difference from near and far wall reflections, which was measured from the ultrasound pulse echo. The angle between the ultrasound beam and the flow was found by using the cross-correlation from consecutive ultrasound echoes. Artificial blood flowing through three different polymer tubes was experimented with, while keeping the same volumetric flow rate. The discrepancy in flow measurement results between this CMUT meter and a calibrated laser Doppler flowmeter is less than 5%.

  9. High volumetric power density, non-enzymatic, glucose fuel cells

    PubMed Central

    Oncescu, Vlad; Erickson, David

    2013-01-01

    The development of new implantable medical devices has been limited in the past by slow advances in lithium battery technology. Non-enzymatic glucose fuel cells are promising replacement candidates for lithium batteries because of good long-term stability and adequate power density. The devices developed to date however use an “oxygen depletion design” whereby the electrodes are stacked on top of each other leading to low volumetric power density and complicated fabrication protocols. Here we have developed a novel single-layer fuel cell with good performance (2 μW cm−2) and stability that can be integrated directly as a coating layer on large implantable devices, or stacked to obtain a high volumetric power density (over 16 μW cm−3). This represents the first demonstration of a low volume non-enzymatic fuel cell stack with high power density, greatly increasing the range of applications for non-enzymatic glucose fuel cells. PMID:23390576

  10. Volumetric Intraoperative Brain Deformation Compensation: Model Development and Phantom Validation

    PubMed Central

    DeLorenzo, Christine; Papademetris, Xenophon; Staib, Lawrence H.; Vives, Kenneth P.; Spencer, Dennis D.; Duncan, James S.

    2012-01-01

    During neurosurgery, nonrigid brain deformation may affect the reliability of tissue localization based on preoperative images. To provide accurate surgical guidance in these cases, preoperative images must be updated to reflect the intraoperative brain. This can be accomplished by warping these preoperative images using a biomechanical model. Due to the possible complexity of this deformation, intraoperative information is often required to guide the model solution. In this paper, a linear elastic model of the brain is developed to infer volumetric brain deformation associated with measured intraoperative cortical surface displacement. The developed model relies on known material properties of brain tissue, and does not require further knowledge about intraoperative conditions. To provide an initial estimation of volumetric model accuracy, as well as determine the model’s sensitivity to the specified material parameters and surface displacements, a realistic brain phantom was developed. Phantom results indicate that the linear elastic model significantly reduced localization error due to brain shift, from >16 mm to under 5 mm, on average. In addition, though in vivo quantitative validation is necessary, preliminary application of this approach to images acquired during neocortical epilepsy cases confirms the feasibility of applying the developed model to in vivo data. PMID:22562728

  11. Volumetric properties of human islet amyloid polypeptide in liquid water.

    PubMed

    Brovchenko, I; Andrews, M N; Oleinikova, A

    2010-04-28

    The volumetric properties of human islet amyloid polypeptide (hIAPP) in water were studied in a wide temperature range by computer simulations. The intrinsic density rho(p) and the intrinsic thermal expansion coefficient alpha(p) of hIAPP were evaluated by taking into account the difference between the volumetric properties of hydration and bulk water. The density of hydration water rho(h) was found to decrease almost linearly with temperature upon heating and its thermal expansion coefficient was found to be notably higher than that of bulk water. The peptide surface exposed to water is more hydrophobic and its rho(h) is smaller in conformation with a larger number of intrapeptide hydrogen bonds. The two hIAPP peptides studied (with and without disulfide bridge) show negative alpha(p), which is close to zero at 250 K and decreases to approximately -1.5 x 10(-3) K(-1) upon heating to 450 K. The analysis of various structural properties of peptides shows a correlation between the intrinsic peptide volumes and the number of intrapeptide hydrogen bonds. The obtained negative values of alpha(p) can be attributed to the shrinkage of the inner voids of the peptides upon heating.

  12. Volumetric display containing multiple two-dimensional color motion pictures

    NASA Astrophysics Data System (ADS)

    Hirayama, R.; Shiraki, A.; Nakayama, H.; Kakue, T.; Shimobaba, T.; Ito, T.

    2014-06-01

    We have developed an algorithm which can record multiple two-dimensional (2-D) gradated projection patterns in a single three-dimensional (3-D) object. Each recorded pattern has the individual projected direction and can only be seen from the direction. The proposed algorithm has two important features: the number of recorded patterns is theoretically infinite and no meaningful pattern can be seen outside of the projected directions. In this paper, we expanded the algorithm to record multiple 2-D projection patterns in color. There are two popular ways of color mixing: additive one and subtractive one. Additive color mixing used to mix light is based on RGB colors and subtractive color mixing used to mix inks is based on CMY colors. We made two coloring methods based on the additive mixing and subtractive mixing. We performed numerical simulations of the coloring methods, and confirmed their effectiveness. We also fabricated two types of volumetric display and applied the proposed algorithm to them. One is a cubic displays constructed by light-emitting diodes (LEDs) in 8×8×8 array. Lighting patterns of LEDs are controlled by a microcomputer board. The other one is made of 7×7 array of threads. Each thread is illuminated by a projector connected with PC. As a result of the implementation, we succeeded in recording multiple 2-D color motion pictures in the volumetric displays. Our algorithm can be applied to digital signage, media art and so forth.

  13. Volumetric verification of multiaxis machine tool using laser tracker.

    PubMed

    Aguado, Sergio; Samper, David; Santolaria, Jorge; Aguilar, Juan José

    2014-01-01

    This paper aims to present a method of volumetric verification in machine tools with linear and rotary axes using a laser tracker. Beyond a method for a particular machine, it presents a methodology that can be used in any machine type. Along this paper, the schema and kinematic model of a machine with three axes of movement, two linear and one rotational axes, including the measurement system and the nominal rotation matrix of the rotational axis are presented. Using this, the machine tool volumetric error is obtained and nonlinear optimization techniques are employed to improve the accuracy of the machine tool. The verification provides a mathematical, not physical, compensation, in less time than other methods of verification by means of the indirect measurement of geometric errors of the machine from the linear and rotary axes. This paper presents an extensive study about the appropriateness and drawbacks of the regression function employed depending on the types of movement of the axes of any machine. In the same way, strengths and weaknesses of measurement methods and optimization techniques depending on the space available to place the measurement system are presented. These studies provide the most appropriate strategies to verify each machine tool taking into consideration its configuration and its available work space.

  14. Volumetric Verification of Multiaxis Machine Tool Using Laser Tracker

    PubMed Central

    Aguilar, Juan José

    2014-01-01

    This paper aims to present a method of volumetric verification in machine tools with linear and rotary axes using a laser tracker. Beyond a method for a particular machine, it presents a methodology that can be used in any machine type. Along this paper, the schema and kinematic model of a machine with three axes of movement, two linear and one rotational axes, including the measurement system and the nominal rotation matrix of the rotational axis are presented. Using this, the machine tool volumetric error is obtained and nonlinear optimization techniques are employed to improve the accuracy of the machine tool. The verification provides a mathematical, not physical, compensation, in less time than other methods of verification by means of the indirect measurement of geometric errors of the machine from the linear and rotary axes. This paper presents an extensive study about the appropriateness and drawbacks of the regression function employed depending on the types of movement of the axes of any machine. In the same way, strengths and weaknesses of measurement methods and optimization techniques depending on the space available to place the measurement system are presented. These studies provide the most appropriate strategies to verify each machine tool taking into consideration its configuration and its available work space. PMID:25202744

  15. Histology-derived volumetric annotation of the human hippocampal subfields in postmortem MRI

    PubMed Central

    Adler, Daniel H.; Pluta, John; Kadivar, Salmon; Craige, Caryne; Gee, James C.; Avants, Brian B.; Yushkevich, Paul A.

    2013-01-01

    Recently, there has been a growing effort to analyze the morphometry of hippocampal subfields using both in vivo and postmortem magnetic resonance imaging (MRI). However, given that boundaries between subregions of the hippocampal formation (HF) are conventionally defined on the basis of microscopic features that often lack discernible signature in MRI, subfield delineation in MRI literature has largely relied on heuristic geometric rules, the validity of which with respect to the underlying anatomy is largely unknown. The development and evaluation of such rules is challenged by the limited availability of data linking MRI appearance to microscopic hippocampal anatomy, particularly in three dimensions (3D). The present paper, for the first time, demonstrates the feasibility of labeling hippocampal subfields in a high resolution volumetric MRI dataset based directly on microscopic features extracted from histology. It uses a combination of computational techniques and manual post-processing to map subfield boundaries from a stack of histology images (obtained with 200 μm spacing and 5 μm slice thickness; stained using the Kluver-Barrera method) onto a postmortem 9.4 Tesla MRI scan of the intact, whole hippocampal formation acquired with 160 μm isotropic resolution. The histology reconstruction procedure consists of sequential application of a graph-theoretic slice stacking algorithm that mitigates the effects of distorted slices, followed by iterative affine and diffeomorphic co-registration to postmortem MRI scans of approximately 1 cm-thick tissue sub-blocks acquired with 200 μm isotropic resolution. These 1 cm blocks are subsequently co-registered to the MRI of the whole HF. Reconstruction accuracy is evaluated as the average displacement error between boundaries manually delineated in both the histology and MRI following the sequential stages of reconstruction. The methods presented and evaluated in this single-subject study can potentially be applied to

  16. Histology-derived volumetric annotation of the human hippocampal subfields in postmortem MRI.

    PubMed

    Adler, Daniel H; Pluta, John; Kadivar, Salmon; Craige, Caryne; Gee, James C; Avants, Brian B; Yushkevich, Paul A

    2014-01-01

    Recently, there has been a growing effort to analyze the morphometry of hippocampal subfields using both in vivo and postmortem magnetic resonance imaging (MRI). However, given that boundaries between subregions of the hippocampal formation (HF) are conventionally defined on the basis of microscopic features that often lack discernible signature in MRI, subfield delineation in MRI literature has largely relied on heuristic geometric rules, the validity of which with respect to the underlying anatomy is largely unknown. The development and evaluation of such rules are challenged by the limited availability of data linking MRI appearance to microscopic hippocampal anatomy, particularly in three dimensions (3D). The present paper, for the first time, demonstrates the feasibility of labeling hippocampal subfields in a high resolution volumetric MRI dataset based directly on microscopic features extracted from histology. It uses a combination of computational techniques and manual post-processing to map subfield boundaries from a stack of histology images (obtained with 200μm spacing and 5μm slice thickness; stained using the Kluver-Barrera method) onto a postmortem 9.4Tesla MRI scan of the intact, whole hippocampal formation acquired with 160μm isotropic resolution. The histology reconstruction procedure consists of sequential application of a graph-theoretic slice stacking algorithm that mitigates the effects of distorted slices, followed by iterative affine and diffeomorphic co-registration to postmortem MRI scans of approximately 1cm-thick tissue sub-blocks acquired with 200μm isotropic resolution. These 1cm blocks are subsequently co-registered to the MRI of the whole HF. Reconstruction accuracy is evaluated as the average displacement error between boundaries manually delineated in both the histology and MRI following the sequential stages of reconstruction. The methods presented and evaluated in this single-subject study can potentially be applied to multiple

  17. The role of cellular environment in dynamic light scattering

    NASA Astrophysics Data System (ADS)

    An, Ran; Jeong, Kwan; Turek, John; Nolte, David

    2011-03-01

    We have developed motility contrast imaging (MCI) as a coherence-domain volumetric imaging approach that uses subcellular dynamics as an endogenous imaging contrast agent of living tissue. Fluctuation spectroscopy analysis of dynamic light scattering (DLS) from 3-D tissue has identified functional frequency bands related to organelle transport, membrane undulations and cell shape change. In this paper, we track the behavior of dynamic light scattering as we bridge the gap between the two extremes of 2-D cell culture on the one hand, and 3-D tissue spheroids on the other. In a light backscattering geometry, we capture speckle from 2-D cell culture consisting of isolated cells or planar rafts of cells on cell-culture surfaces. DLS from that cell culture shows differences and lower sensitivity to intra-cellular dynamics compared with the 3-D tissue. The motility contrast is weak in this limit. As the cellular density increases to cover the surface, the motility contrast increases. As environmental perturbations or pharmaceuticals are applied, the fluctuation spectral response becomes more dramatic as the dimensionality of the cellular aggregations increases. We show that changing optical thickness of the cellular-to-tissue targets usually causes characteristic frequency shifts in the spectrograms, while changing cellular dimensionality causes characteristic frequencies to be enhanced or suppressed.

  18. Asynchronous Inflammation and Myogenic Cell Migration Limit Muscle Tissue Regeneration Mediated by a Cellular Scaffolds

    DTIC Science & Technology

    2015-02-11

    is to restore strength to the injured musculature by regenerating appreciable and functional muscle tissue. At the forefront of these efforts are...of 5 Asynchronous inflammation and myogenic cell migration limit muscle tissue regeneration mediated by a cellular scaffolds Koyal Garg1...benjamin.t.corona.vol@mail.mil or corona.benjamin.t@gmail.com Received: January 14, 2015 Published online: February 11, 2015 Volumetric muscle loss (VML

  19. Microscope Resolution.

    ERIC Educational Resources Information Center

    Higbie, J.

    1981-01-01

    Describes problems using the Jenkins and White approach and standard diffraction theory when dealing with the topic of finite conjugate, point-source resolution and how they may be resolved using the relatively obscure Abbe's sine theorem. (JN)

  20. 47 CFR 22.972 - Interference resolution procedures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... cell parameters that may need to be adjusted is left to the discretion of the Cellular Radiotelephone... PUBLIC MOBILE SERVICES Cellular Radiotelephone Service § 22.972 Interference resolution procedures. (a) Initial notification. (1) Cellular Radiotelephone licensees may receive initial notification...

  1. Volumetric and two-dimensional image interpretation show different cognitive processes in learners.

    PubMed

    van der Gijp, Anouk; Ravesloot, Cécile J; van der Schaaf, Marieke F; van der Schaaf, Irene C; Huige, Josephine C B M; Vincken, Koen L; Ten Cate, Olle Th J; van Schaik, Jan P J

    2015-05-01

    In current practice, radiologists interpret digital images, including a substantial amount of volumetric images. We hypothesized that interpretation of a stack of a volumetric data set demands different skills than interpretation of two-dimensional (2D) cross-sectional images. This study aimed to investigate and compare knowledge and skills used for interpretation of volumetric versus 2D images. Twenty radiology clerks were asked to think out loud while reading four or five volumetric computed tomography (CT) images in stack mode and four or five 2D CT images. Cases were presented in a digital testing program allowing stack viewing of volumetric data sets and changing views and window settings. Thoughts verbalized by the participants were registered and coded by a framework of knowledge and skills concerning three components: perception, analysis, and synthesis. The components were subdivided into 16 discrete knowledge and skill elements. A within-subject analysis was performed to compare cognitive processes during volumetric image readings versus 2D cross-sectional image readings. Most utterances contained knowledge and skills concerning perception (46%). A smaller part involved synthesis (31%) and analysis (23%). More utterances regarded perception in volumetric image interpretation than in 2D image interpretation (Median 48% vs 35%; z = -3.9; P < .001). Synthesis was less prominent in volumetric than in 2D image interpretation (Median 28% vs 42%; z = -3.9; P < .001). No differences were found in analysis utterances. Cognitive processes in volumetric and 2D cross-sectional image interpretation differ substantially. Volumetric image interpretation draws predominantly on perceptual processes, whereas 2D image interpretation is mainly characterized by synthesis. The results encourage the use of volumetric images for teaching and testing perceptual skills. Copyright © 2015 AUR. Published by Elsevier Inc. All rights reserved.

  2. Volumetric evaluation of fat resorption after breast lipofilling.

    PubMed

    Ho Quoc, C; Taupin, T; Guérin, N; Delay, E

    2015-12-01

    The fat transfer or the lipofilling is a technique that had a major impact on the breast surgery results. We have been using this technique since 1998 as an adjuvant in breast reconstruction. The transferred fat is partially resorbed in the first three months after fat grafting. Literature shows that fat resorption varies from 30 to 80% and the experimental studies register a variation between 50 and 90%. The difficulty of the lipomodeling consists in anticipating the fat resorption rate in order to obtain breast symmetry. The purpose of this article is to evaluate the resorption rate of the transferred fat in the reconstructed breast by means of volumetric imaging 3 months after fat grafting. A prospective study was undertaken including breast reconstructions with total autologous latissimus dorsi. All the surgical procedures have been done by the same surgeon (1st author). It focused on the second stage of breast reconstruction: the lipofilling. We registered the average harvested volumes, the volumes obtained after centrifugation and the transferred volumes for every reconstructed breast. The intramuscular volume in the reconstructed breast was measured by volumetric imaging on the third day after lipofilling (D3) and three months after lipofilling (M3). The volumetry was performed by using an after treatment console SIEMENS (SOMATOM definition AS 2*64 barettes). The average intramuscular volume was registered at D3 and M3. The average volume difference was calculated in order to obtain the exact resorption rate. This prospective study was undertaken on 32 reconstructed breasts by total autologous latissimus dorsi flap. The average age was 52 years, the average BMI was 24.7 kg/m(2). The average harvested fat volume for the breast lipofilling was 560 cc and the volume obtained after centrifugation was evaluated at about 371 cc, the average fat volume transferred being 291 cc. The volumetric study showed that intramuscular volume at D3 was measured at 284 cc and

  3. The efficiency of a volumetric alcohol tax in Australia.

    PubMed

    Byrnes, Joshua; Petrie, Dennis J; Doran, Christopher M; Shakeshaft, Anthony

    2012-01-01

    In Australia and elsewhere, fiscal measures such as alcohol taxation are a commonly used intervention and cost-effective strategy to reduce alcohol consumption and associated harm. However, alcohol taxation policies distort the market for alcohol, specifically increasing the marginal cost of alcohol. It is proposed that a volumetric tax, which taxes alcohol equally across all beverage types, is less distortive of consumer preferences and more efficient at reducing alcohol consumption than the current Australian tax model, where taxes are charged at varying amounts per litre of pure alcohol, depending on the beverage type. This paper quantifies the effect of four different alcohol taxation systems, relative to the current Australian system: two different types of volumetric taxation (deadweight loss neutral and tax revenue neutral); the recent strategy trialled in Australia of increasing the tax only on ready-to-drink alcoholic beverages (i.e. premixed spirits); and a tiered tax system, which may be more politically acceptable. A partial equilibrium approach was used to measure taxation revenue, consumer welfare and consumption in alcohol markets. Estimates of taxation revenue, consumer welfare and consumption were first calculated for 2008 and then compared with the four scenarios considered. Relative to the previous alcohol taxation scheme in Australia, the taxation strategy that increased the tax solely on ready-to-drink alcoholic beverages increased taxation revenue by 479 million Australian dollars ($A), reduced pure alcohol consumption by 754 000 litres and increased the net deadweight loss of taxation by $A62 million. For a tax-neutral approach, for the same level of taxation revenue as is currently generated, a volumetric tax could substantially reduce the cost of taxation (as described by the net loss in consumer welfare) by $A177 million and reduce pure alcohol consumption by 4 68 000 litres. Under a deadweight loss-neutral scenario, for the same

  4. Rapid mapping of volumetric machine errors using distance measurements

    SciTech Connect

    Krulewich, D.A.

    1998-04-01

    This paper describes a relatively inexpensive, fast, and easy to execute approach to maping the volumetric errors of a machine tool, coordinate measuring machine, or robot. An error map is used to characterize a machine or to improve its accuracy by compensating for the systematic errors. The method consists of three steps: (1) models the relationship between volumetric error and the current state of the machine, (2) acquiring error data based on distance measurements throughout the work volume; and (3)fitting the error model using the nonlinear equation for the distance. The error model is formulated from the kinematic relationship among the six degrees of freedom of error an each moving axis. Expressing each parametric error as function of position each is combined to predict the error between the functional point and workpiece, also as a function of position. A series of distances between several fixed base locations and various functional points in the work volume is measured using a Laser Ball Bar (LBB). Each measured distance is a non-linear function dependent on the commanded location of the machine, the machine error, and the location of the base locations. Using the error model, the non-linear equation is solved producing a fit for the error model Also note that, given approximate distances between each pair of base locations, the exact base locations in the machine coordinate system determined during the non-linear filling procedure. Furthermore, with the use of 2048 more than three base locations, bias error in the measuring instrument can be removed The volumetric errors of three-axis commercial machining center have been mapped using this procedure. In this study, only errors associated with the nominal position of the machine were considered Other errors such as thermally induced and load induced errors were not considered although the mathematical model has the ability to account for these errors. Due to the proprietary nature of the projects we are

  5. Architected Cellular Materials

    NASA Astrophysics Data System (ADS)

    Schaedler, Tobias A.; Carter, William B.

    2016-07-01

    Additive manufacturing enables fabrication of materials with intricate cellular architecture, whereby progress in 3D printing techniques is increasing the possible configurations of voids and solids ad infinitum. Examples are microlattices with graded porosity and truss structures optimized for specific loading conditions. The cellular architecture determines the mechanical properties and density of these materials and can influence a wide range of other properties, e.g., acoustic, thermal, and biological properties. By combining optimized cellular architectures with high-performance metals and ceramics, several lightweight materials that exhibit strength and stiffness previously unachievable at low densities were recently demonstrated. This review introduces the field of architected materials; summarizes the most common fabrication methods, with an emphasis on additive manufacturing; and discusses recent progress in the development of architected materials. The review also discusses important applications, including lightweight structures, energy absorption, metamaterials, thermal management, and bioscaffolds.

  6. Irregular Cellular Learning Automata.

    PubMed

    Esnaashari, Mehdi; Meybodi, Mohammad Reza

    2015-08-01

    Cellular learning automaton (CLA) is a recently introduced model that combines cellular automaton (CA) and learning automaton (LA). The basic idea of CLA is to use LA to adjust the state transition probability of stochastic CA. This model has been used to solve problems in areas such as channel assignment in cellular networks, call admission control, image processing, and very large scale integration placement. In this paper, an extension of CLA called irregular CLA (ICLA) is introduced. This extension is obtained by removing the structure regularity assumption in CLA. Irregularity in the structure of ICLA is needed in some applications, such as computer networks, web mining, and grid computing. The concept of expediency has been introduced for ICLA and then, conditions under which an ICLA becomes expedient are analytically found.

  7. Epigenetics and Cellular Metabolism

    PubMed Central

    Xu, Wenyi; Wang, Fengzhong; Yu, Zhongsheng; Xin, Fengjiao

    2016-01-01

    Living eukaryotic systems evolve delicate cellular mechanisms for responding to various environmental signals. Among them, epigenetic machinery (DNA methylation, histone modifications, microRNAs, etc.) is the hub in transducing external stimuli into transcriptional response. Emerging evidence reveals the concept that epigenetic signatures are essential for the proper maintenance of cellular metabolism. On the other hand, the metabolite, a main environmental input, can also influence the processing of epigenetic memory. Here, we summarize the recent research progress in the epigenetic regulation of cellular metabolism and discuss how the dysfunction of epigenetic machineries influences the development of metabolic disorders such as diabetes and obesity; then, we focus on discussing the notion that manipulating metabolites, the fuel of cell metabolism, can function as a strategy for interfering epigenetic machinery and its related disease progression as well. PMID:27695375

  8. Fatigue of cellular materials

    SciTech Connect

    Huang, J.S.; Lin, J.Y.

    1996-01-01

    The fatigue of cellular materials is analyzed using dimensional arguments. When the first unbroken cell wall ahead of the macrocrack tip fails after some cycles of loading, the macrocrack advances one cell diameter, giving the macrocrack growth rate of cellular materials. Paris law for microcrack propagation, Basquin law for high cycle fatigue and Coffin-Manson law for low cycle fatigue are employed in calculating the number of cycles to failure of the first unbroken cell wall ahead of the macrocrack tip. It is found that fatigue of cellular materials depends on cyclic stress intensity range, cell size, relative density and the fatigue parameters of the solid from which they are made. Theoretical modelling of fatigue of foams is compared to data in polymer foams; agreement is good.

  9. Temporally flickering nanoparticles for compound cellular imaging and super resolution

    NASA Astrophysics Data System (ADS)

    Ilovitsh, Tali; Danan, Yossef; Meir, Rinat; Meiri, Amihai; Zalevsky, Zeev

    2016-03-01

    This work presents the use of flickering nanoparticles for imaging biological samples. The method has high noise immunity, and it enables the detection of overlapping types of GNPs, at significantly sub-diffraction distances, making it attractive for super resolving localization microscopy techniques. The method utilizes a lock-in technique at which the imaging of the sample is done using a time-modulated laser beam that match the number of the types of gold nanoparticles (GNPs) that label a given sample, and resulting in the excitation of the temporal flickering of the scattered light at known temporal frequencies. The final image where the GNPs are spatially separated is obtained using post processing where the proper spectral components corresponding to the different modulation frequencies are extracted. This allows the simultaneous super resolved imaging of multiple types of GNPs that label targets of interest within biological samples. Additionally applying the post-processing algorithm of the K-factor image decomposition algorithm can further improve the performance of the proposed approach.

  10. Cellular immunotherapies for cancer.

    PubMed

    Berraondo, Pedro; Labiano, Sara; Minute, Luna; Etxeberria, Iñaki; Vasquez, Marcos; Sanchez-Arraez, Alvaro; Teijeira, Alvaro; Melero, Ignacio

    2017-01-01

    Lessons learned over decades on the use of gene and cell therapies have found clinical applicability in the field of cancer immunotherapy. On December 16(th), 2016 a symposium was held in Pamplona (Spain) to analyze and discuss the critical points for the clinical success of adoptive cell transfer strategies in cancer immunotherapy. Cellular immunotherapy is being currently exploited for the development of new cancer vaccines using ex vivo manipulated dendritic cells or to enhance the number of effector cells, transferring reinvigorated NK cells or T cells. In this meeting report, we summarize the main topics covered and provide an overview of the field of cellular immunotherapy.

  11. Cellular structural biology.

    PubMed

    Ito, Yutaka; Selenko, Philipp

    2010-10-01

    While we appreciate the complexity of the intracellular environment as a general property of every living organism, we collectively lack the appropriate tools to analyze protein structures in a cellular context. In-cell NMR spectroscopy represents a novel biophysical tool to investigate the conformational and functional characteristics of biomolecules at the atomic level inside live cells. Here, we review recent in-cell NMR developments and provide an outlook towards future applications in prokaryotic and eukaryotic cells. We hope to thereby emphasize the usefulness of in-cell NMR techniques for cellular studies of complex biological processes and for structural analyses in native environments. Copyright © 2010 Elsevier Ltd. All rights reserved.

  12. Repeated mild traumatic brain injuries is not associated with volumetric differences in former high school football players.

    PubMed

    Terry, Douglas P; Miller, L Stephen

    2017-04-22

    We investigated potential brain volumetric differences in a sample of former high school football players many years after these injuries. Forty community-dwelling males ages 40-65 who played high school football, but not college or professional sports, were recruited. The experimental group (n = 20) endorsed experiencing two or more mTBIs on an empirically validated mTBI assessment tool (median = 3, range = 2-15). The control group (n = 20) denied ever experiencing an mTBI. Participants completed a self-report index of current mTBI symptomatology and underwent high-resolution T1-weighted MRI scanning, which were analyzed using the Freesurfer software package. A priori regions of interest (ROIs) included total intracranial volume (ICV), total gray matter, total white matter, bilateral anterior cingulate cortex, bilateral hippocampi, and lateral ventricles. ROIs were corrected for head size using a normalization method that took ICV into account. Despite an adequate sample size and being matched on age, education, estimated premorbid IQ, current concussive symptomatology, there were no statistically significant volumetric group differences across all of the ROIs. These data suggest that multiple mTBIs from high school football may not be associated with measurable brain atrophy later in life. Accounting for the severity of injury and chronicity of sport exposure may be especially important when measuring long-term neuroanatomical differences.

  13. A Combined Random Forests and Active Contour Model Approach for Fully Automatic Segmentation of the Left Atrium in Volumetric MRI

    PubMed Central

    Luo, Gongning

    2017-01-01

    Segmentation of the left atrium (LA) from cardiac magnetic resonance imaging (MRI) datasets is of great importance for image guided atrial fibrillation ablation, LA fibrosis quantification, and cardiac biophysical modelling. However, automated LA segmentation from cardiac MRI is challenging due to limited image resolution, considerable variability in anatomical structures across subjects, and dynamic motion of the heart. In this work, we propose a combined random forests (RFs) and active contour model (ACM) approach for fully automatic segmentation of the LA from cardiac volumetric MRI. Specifically, we employ the RFs within an autocontext scheme to effectively integrate contextual and appearance information from multisource images together for LA shape inferring. The inferred shape is then incorporated into a volume-scalable ACM for further improving the segmentation accuracy. We validated the proposed method on the cardiac volumetric MRI datasets from the STACOM 2013 and HVSMR 2016 databases and showed that it outperforms other latest automated LA segmentation methods. Validation metrics, average Dice coefficient (DC) and average surface-to-surface distance (S2S), were computed as 0.9227 ± 0.0598 and 1.14 ± 1.205 mm, versus those of 0.6222–0.878 and 1.34–8.72 mm, obtained by other methods, respectively. PMID:28316992

  14. Optimization approaches to volumetric modulated arc therapy planning.

    PubMed

    Unkelbach, Jan; Bortfeld, Thomas; Craft, David; Alber, Markus; Bangert, Mark; Bokrantz, Rasmus; Chen, Danny; Li, Ruijiang; Xing, Lei; Men, Chunhua; Nill, Simeon; Papp, Dávid; Romeijn, Edwin; Salari, Ehsan

    2015-03-01

    Volumetric modulated arc therapy (VMAT) has found widespread clinical application in recent years. A large number of treatment planning studies have evaluated the potential for VMAT for different disease sites based on the currently available commercial implementations of VMAT planning. In contrast, literature on the underlying mathematical optimization methods used in treatment planning is scarce. VMAT planning represents a challenging large scale optimization problem. In contrast to fluence map optimization in intensity-modulated radiotherapy planning for static beams, VMAT planning represents a nonconvex optimization problem. In this paper, the authors review the state-of-the-art in VMAT planning from an algorithmic perspective. Different approaches to VMAT optimization, including arc sequencing methods, extensions of direct aperture optimization, and direct optimization of leaf trajectories are reviewed. Their advantages and limitations are outlined and recommendations for improvements are discussed.

  15. Feature-driven data exploration for volumetric rendering.

    PubMed

    Woo, Insoo; Maciejewski, Ross; Gaither, Kelly P; Ebert, David S

    2012-10-01

    We have developed an intuitive method to semiautomatically explore volumetric data in a focus-region-guided or value-driven way using a user-defined ray through the 3D volume and contour lines in the region of interest. After selecting a point of interest from a 2D perspective, which defines a ray through the 3D volume, our method provides analytical tools to assist in narrowing the region of interest to a desired set of features. Feature layers are identified in a 1D scalar value profile with the ray and are used to define default rendering parameters, such as color and opacity mappings, and locate the center of the region of interest. Contour lines are generated based on the feature layer level sets within interactively selected slices of the focus region. Finally, we utilize feature-preserving filters and demonstrate the applicability of our scheme to noisy data.

  16. Volumetric properties of water/AOT/isooctane microemulsions.

    PubMed

    Du, Changfei; He, Wei; Yin, Tianxiang; Shen, Weiguo

    2014-12-23

    The densities of AOT/isooctane micelles and water/AOT/isooctane microemulsions with the molar ratios R of water to AOT being 2, 8, 10, 12, 16, 18, 20, 25, 30, and 40 were measured at 303.15 K. The apparent specific volumes of AOT and the quasi-component water/AOT at various concentrations were calculated and used to estimate the volumetric properties of AOT and water in the droplets and in the continuous oil phase, to discuss the interaction between the droplets, and to determine the critical micelle concentration and the critical microemulsion concentrations. A thermodynamic model was proposed to analysis the stability boundary of the microemulsion droplets, which confirms the maximum value of R being about 65 for the stable AOT/water/isooctane microemulsion droplets.

  17. Electrothermal energy conversion using electron gas volumetric change inside semiconductors

    SciTech Connect

    Yazawa, K.; Shakouri, A.

    2016-07-25

    We propose and analyze an electrothermal energy converter using volumetric changes in non-equilibrium electron gas inside semiconductors. The geometric concentration of electron gas under an electric field increases the effective pressure of the electrons, and then a barrier filters out cold electrons, acting like a valve. Nano- and micro-scale features enable hot electrons to arrive at the contact in a short enough time to avoid thermalization with the lattice. Key length and time scales, preliminary device geometry, and anticipated efficiency are estimated for electronic analogs of Otto and Brayton power generators and Joule-Thomson micro refrigerators on a chip. The power generators convert the energy of incident photons from the heat source to electrical current, and the refrigerator can reduce the temperature of electrons in a semiconductor device. The analytic calculations show that a large energy conversion efficiency or coefficient of performance may be possible.

  18. Semi-automatic volumetrics system to parcellate ROI on neocortex

    NASA Astrophysics Data System (ADS)

    Tan, Ou; Ichimiya, Tetsuya; Yasuno, Fumihiko; Suhara, Tetsuya

    2002-05-01

    A template-based and semi-automatic volumetrics system--BrainVol is build to divide the any given patient brain to neo-cortical and sub-cortical regions. The standard region is given as standard ROI drawn on a standard brain volume. After normalization between the standard MR image and the patient MR image, the sub-cortical ROIs' boundary are refined based on gray matter. The neo-cortical ROIs are refined by sulcus information that is semi-automatically marked on the patient brain. Then the segmentation is applied to 4D PET image of same patient for calculation of TAC (Time Activity Curve) by co-registration between MR and PET.

  19. Three-Dimensional Volumetric Restoration by Structural Fat Grafting

    PubMed Central

    Clauser, Luigi C.; Consorti, Giuseppe; Elia, Giovanni; Galié, Manlio; Tieghi, Riccardo

    2013-01-01

    The use of adipose tissue transfer for correction of maxillofacial defects was reported for the first time at the end of the 19th century. Structural fat grafting (SFG) was introduced as a way to improve facial esthetics and in recent years has evolved into applications in craniomaxillofacial reconstructive surgery. Several techniques have been proposed for harvesting and grafting the fat. However, owing to the damage of many adipocytes during these maneuvers, the results have not been satisfactory and have required several fat injection procedures for small corrections. The author's (L.C.) overview the application of SFG in the management of volumetric deficit in the craniomaxillofacial in patients treated with a long-term follow-up. PMID:24624259

  20. Optimization approaches to volumetric modulated arc therapy planning

    SciTech Connect

    Unkelbach, Jan Bortfeld, Thomas; Craft, David; Alber, Markus; Bangert, Mark; Bokrantz, Rasmus; Chen, Danny; Li, Ruijiang; Xing, Lei; Men, Chunhua; Nill, Simeon; Papp, Dávid; Romeijn, Edwin; Salari, Ehsan

    2015-03-15

    Volumetric modulated arc therapy (VMAT) has found widespread clinical application in recent years. A large number of treatment planning studies have evaluated the potential for VMAT for different disease sites based on the currently available commercial implementations of VMAT planning. In contrast, literature on the underlying mathematical optimization methods used in treatment planning is scarce. VMAT planning represents a challenging large scale optimization problem. In contrast to fluence map optimization in intensity-modulated radiotherapy planning for static beams, VMAT planning represents a nonconvex optimization problem. In this paper, the authors review the state-of-the-art in VMAT planning from an algorithmic perspective. Different approaches to VMAT optimization, including arc sequencing methods, extensions of direct aperture optimization, and direct optimization of leaf trajectories are reviewed. Their advantages and limitations are outlined and recommendations for improvements are discussed.

  1. Electrothermal energy conversion using electron gas volumetric change inside semiconductors

    NASA Astrophysics Data System (ADS)

    Yazawa, K.; Shakouri, A.

    2016-07-01

    We propose and analyze an electrothermal energy converter using volumetric changes in non-equilibrium electron gas inside semiconductors. The geometric concentration of electron gas under an electric field increases the effective pressure of the electrons, and then a barrier filters out cold electrons, acting like a valve. Nano- and micro-scale features enable hot electrons to arrive at the contact in a short enough time to avoid thermalization with the lattice. Key length and time scales, preliminary device geometry, and anticipated efficiency are estimated for electronic analogs of Otto and Brayton power generators and Joule-Thomson micro refrigerators on a chip. The power generators convert the energy of incident photons from the heat source to electrical current, and the refrigerator can reduce the temperature of electrons in a semiconductor device. The analytic calculations show that a large energy conversion efficiency or coefficient of performance may be possible.

  2. The effects of common medications on volumetric phallometry

    PubMed Central

    Lykins, Amy D.; Robinson, Jennifer J.; LeBlanc, Serge; Cantor, James M.

    2015-01-01

    Abstract Phallometry is a physiological measure of sexual response widely used for the assessment of paedophilia among sexual offenders. Although many medications decrease penile response sufficiently to interfere with sexual intercourse, it is unknown to what extent such medications might interfere with phallometric testing. In the current study, we utilized a naturalistic convenience sample of 1078 men who attended a clinic for assessment of sexual preferences, mostly related to sexual offence convictions. In the present analyses, we quantified the differences in penile response during phallometric assessment associated with taking a range of common medications. Participants on medication typically showed less penile output than participants not taking medications; however, differences were largely accounted for by age rather than by medication status. Though most medications were associated with decreases in penile responsivity during volumetric phallometric testing, such changes were small in absolute terms and appeared to be associated with ageing rather than with the medications themselves. PMID:26549976

  3. Volumetric leak detection in large underground storage tanks. Volume 1

    SciTech Connect

    Starr, J.W.; Wise, R.F.; Maresca, J.W.

    1991-08-01

    A set of experiments was conducted to determine whether volumetric leak detection system presently used to test underground storage tanks (USTs) up to 38,000 L (10,000 gal) in capacity could meet EPA's regulatory standards for tank tightness and automatic tank gauging systems when used to test tanks up to 190,000 L (50,000 gal) in capacity. The experiments, conducted on two partially filled 190,000-L (50,000-gal) USTs at Griffiss Air Force Base in upstate New York during late August 1990, showed that a system's performance in large tanks depends primarily on the accuracy of the temperature compensation, which is inversely proportional to the volume of product in the tank. Errors in temperature compensation that were negligible in tests in small tanks were important in large tanks. The experiments further suggest that a multiple-test strategy is also required.

  4. Updated Volumetric Expansion Factors for K Basin Sludge During Storage

    SciTech Connect

    Schmidt, Andrew J. ); Delegard, Calvin H. )

    2003-03-14

    Sludge has accumulated in the K East (KE) and K West (KW) Basins at the Hanford Site. This sludge contains metallic uranium and uranium oxides that will corrode, hydrate, and generate and consume gases during containerized storage. From these corrosion reactions, two sludge expansion mechanisms can be expected: 1) expansion of the volume of the sludge solids from the generation of corrosion oxidation products that occupy more space than the starting-state sludge; and 2) expansion of the bulk sludge volume from the retention of hydrogen gas bubbles. This report provides a review and updated projections of the volumetric expansion occurring due to corrosion and gas retention during the containerized storage of K Basin sludge. New design and safety basis volume expansion values are provided for the following sludge streams: KW Floor, KW North Loadout Pit, KW canister, and fuel piece sludge.

  5. Volumetric dispenser for small particles from plural sources

    DOEpatents

    Bradley, R.A.; Miller, W.H.; Sease, J.D.

    1975-12-16

    Apparatus is described for rapidly and accurately dispensing measured volumes of small particles from a supply hopper. The apparatus includes an adjustable, vertically oriented measuring tube and orifice member defining the volume to be dispensed, a ball plug valve for selectively closing the bottom end of the orifice member, and a compression valve for selectively closing the top end of the measuring tube. A supply hopper is disposed above and in gravity flow communication with the measuring tube. Properly sequenced opening and closing of the two valves provides accurate volumetric discharge through the ball plug valve. A dispensing system is described wherein several appropriately sized measuring tubes, orifice members, and associated valves are arranged to operate contemporaneously to facilitate blending of different particles.

  6. Volumetric-driven flows on the Plasma Couette Experiment

    NASA Astrophysics Data System (ADS)

    Flanagan, Ken; Clark, M. M.; Lynn, J.; Siller, R.; Tabbutt, M.; Wallace, J.; Xu, Y.; Forest, C. B.

    2016-10-01

    Experiments for driving Keplerian-like flow profiles with the goal of exciting the magnetorotational instability (MRI) on the Plasma Couette Experiment Upgrade (PCX-U) are described. Instead of driving flow at the boundaries as is typical in many liquid metal Couette experiments, a global drive is implemented. A large (20+ A) radial current is drawn across a small (1-3 G) axial field generating torque across the whole profile. This volumetric-driven flow (VDF) is capable of producing profiles similar to Keplerian flow with Alfvén Mach numbers of order unity-ideal for MRI studies. Experimental measurements will be compared to numerical calculations that show that at sufficiently high magnetic and fluid Reynolds numbers, VDF can drive the MRI. This work is supported by the NSF.

  7. Marginal Space Deep Learning: Efficient Architecture for Volumetric Image Parsing.

    PubMed

    Ghesu, Florin C; Krubasik, Edward; Georgescu, Bogdan; Singh, Vivek; Yefeng Zheng; Hornegger, Joachim; Comaniciu, Dorin

    2016-05-01

    Robust and fast solutions for anatomical object detection and segmentation support the entire clinical workflow from diagnosis, patient stratification, therapy planning, intervention and follow-up. Current state-of-the-art techniques for parsing volumetric medical image data are typically based on machine learning methods that exploit large annotated image databases. Two main challenges need to be addressed, these are the efficiency in scanning high-dimensional parametric spaces and the need for representative image features which require significant efforts of manual engineering. We propose a pipeline for object detection and segmentation in the context of volumetric image parsing, solving a two-step learning problem: anatomical pose estimation and boundary delineation. For this task we introduce Marginal Space Deep Learning (MSDL), a novel framework exploiting both the strengths of efficient object parametrization in hierarchical marginal spaces and the automated feature design of Deep Learning (DL) network architectures. In the 3D context, the application of deep learning systems is limited by the very high complexity of the parametrization. More specifically 9 parameters are necessary to describe a restricted affine transformation in 3D, resulting in a prohibitive amount of billions of scanning hypotheses. The mechanism of marginal space learning provides excellent run-time performance by learning classifiers in clustered, high-probability regions in spaces of gradually increasing dimensionality. To further increase computational efficiency and robustness, in our system we learn sparse adaptive data sampling patterns that automatically capture the structure of the input. Given the object localization, we propose a DL-based active shape model to estimate the non-rigid object boundary. Experimental results are presented on the aortic valve in ultrasound using an extensive dataset of 2891 volumes from 869 patients, showing significant improvements of up to 45

  8. Quantitative volumetric breast density estimation using phase contrast mammography

    NASA Astrophysics Data System (ADS)

    Wang, Zhentian; Hauser, Nik; Kubik-Huch, Rahel A.; D'Isidoro, Fabio; Stampanoni, Marco

    2015-05-01

    Phase contrast mammography using a grating interferometer is an emerging technology for breast imaging. It provides complementary information to the conventional absorption-based methods. Additional diagnostic values could be further obtained by retrieving quantitative information from the three physical signals (absorption, differential phase and small-angle scattering) yielded simultaneously. We report a non-parametric quantitative volumetric breast density estimation method by exploiting the ratio (dubbed the R value) of the absorption signal to the small-angle scattering signal. The R value is used to determine breast composition and the volumetric breast density (VBD) of the whole breast is obtained analytically by deducing the relationship between the R value and the pixel-wise breast density. The proposed method is tested by a phantom study and a group of 27 mastectomy samples. In the clinical evaluation, the estimated VBD values from both cranio-caudal (CC) and anterior-posterior (AP) views are compared with the ACR scores given by radiologists to the pre-surgical mammograms. The results show that the estimated VBD results using the proposed method are consistent with the pre-surgical ACR scores, indicating the effectiveness of this method in breast density estimation. A positive correlation is found between the estimated VBD and the diagnostic ACR score for both the CC view (p=0.033 ) and AP view (p=0.001 ). A linear regression between the results of the CC view and AP view showed a correlation coefficient γ = 0.77, which indicates the robustness of the proposed method and the quantitative character of the additional information obtained with our approach.

  9. The volumetric rate of superluminous supernovae at z ˜ 1

    NASA Astrophysics Data System (ADS)

    Prajs, S.; Sullivan, M.; Smith, M.; Levan, A.; Karpenka, N. V.; Edwards, T. D. P.; Walker, C. R.; Wolf, W. M.; Balland, C.; Carlberg, R.; Howell, D. A.; Lidman, C.; Pain, R.; Pritchet, C.; Ruhlmann-Kleider, V.

    2017-01-01

    We present a measurement of the volumetric rate of superluminous supernovae (SLSNe) at z ˜ 1.0, measured using archival data from the first four years of the Canada-France-Hawaii Telescope Supernova Legacy Survey (SNLS). We develop a method for the photometric classification of SLSNe to construct our sample. Our sample includes two previously spectroscopically identified objects, and a further new candidate selected using our classification technique. We use the point-source recovery efficiencies from Perrett et al. and a Monte Carlo approach to calculate the rate based on our SLSN sample. We find that the three identified SLSNe from SNLS give a rate of 91^{+76}_{-36} SNe yr-1 Gpc-3 at a volume-weighted redshift of z = 1.13. This is equivalent to 2.2^{+1.8}_{-0.9}× 10^{-4} of the volumetric core-collapse supernova rate at the same redshift. When combined with other rate measurements from the literature, we show that the rate of SLSNe increases with redshift in a manner consistent with that of the cosmic star formation history. We also estimate the rate of ultra-long gamma-ray bursts based on the events discovered by the Swift satellite, and show that it is comparable to the rate of SLSNe, providing further evidence of a possible connection between these two classes of events. We also examine the host galaxies of the SLSNe discovered in SNLS, and find them to be consistent with the stellar-mass distribution of other published samples of SLSNe.

  10. A miniature real-time volumetric ultrasound imaging system

    NASA Astrophysics Data System (ADS)

    Wygant, Ira O.; Yeh, David T.; Zhuang, Xuefeng; Nikoozadeh, Amin; Oralkan, Omer; Ergun, Arif S.; Karaman, Mustafa; Khuri-Yakub, Butrus T.

    2005-04-01

    Progress made in the development of a miniature real-time volumetric ultrasound imaging system is presented. This system is targeted for use in a 5-mm endoscopic channel and will provide real-time, 30-mm deep, volumetric images. It is being developed as a clinically useful device, to demonstrate a means of integrating the front-end electronics with the transducer array, and to demonstrate the advantages of the capacitive micromachined ultrasonic transducer (CMUT) technology for medical imaging. Presented here is the progress made towards the initial implementation of this system, which is based on a two-dimensional, 16x16 CMUT array. Each CMUT element is 250 um by 250 um and has a 5 MHz center frequency. The elements are connected to bond pads on the back side of the array with 400-um long through-wafer interconnects. The transducer array is flip-chip bonded to a custom-designed integrated circuit that comprises the front-end electronics. The result is that each transducer element is connected to a dedicated pulser and low-noise preamplifier. The pulser generates 25-V, 100-ns wide, unipolar pulses. The preamplifier has an approximate transimpedance gain of 500 kOhm and 3-dB bandwidth of 10 MHz. In the first implementation of the system, one element at a time can be selected for transmit and receive and thus synthetic aperture images can be generated. In future implementations, 16 channels will be active at a given time. These channels will connect to an FPGA-based data acquisition system for real-time image reconstruction.

  11. Assessment of smoke inhalation injury using volumetric optical frequency domain imaging in sheep models

    NASA Astrophysics Data System (ADS)

    Applegate, Matthew B.; Hariri, Lida P.; Beagle, John; Tan, Khay Ming; Chee, Chunmin; Hales, Charles A.; Suter, Melissa J.

    2012-02-01

    Smoke inhalation injury is a serious threat to victims of fires and explosions, however accurate diagnosis of patients remains problematic. Current evaluation techniques are highly subjective, often involving the integration of clinical findings with bronchoscopic assessment. It is apparent that new quantitative methods for evaluating the airways of patients at risk of inhalation injury are needed. Optical frequency domain imaging (OFDI) is a high resolution optical imaging modality that enables volumetric microscopy of the trachea and upper airways in vivo. We anticipate that OFDI may be a useful tool in accurately assessing the airways of patients at risk of smoke inhalation injury by detecting injury prior to the onset of symptoms, and therefore guiding patient management. To demonstrate the potential of OFDI for evaluating smoke inhalation injury, we conducted a preclinical study in which we imaged the trachea/upper airways of 4 sheep prior to, and up to 60 minutes post exposure to cooled cotton smoke. OFDI enabled the visualization of increased mucus accumulation, mucosal thickening, epithelial disruption and sloughing, and increased submucosal signal intensity attributed to polymorphonuclear infiltrates. These results were consistent with histopathology findings. Bronchoscopic inspection of the upper airways appeared relatively normal with only mild accumulation of mucus visible within the airway lumen. The ability of OFDI to not only accurately detect smoke inhalation injury, but to quantitatively assess and monitor the progression or healing of the injury over time may provide new insights into the management of patients such as guiding clinical decisions regarding the need for intubation and ventilator support.

  12. The investigation of data voxelization for a three-dimensional volumetric display system

    NASA Astrophysics Data System (ADS)

    Xie, Xiaoyan; Liu, Xu; Lin, Yuanfang

    2009-04-01

    A high resolution three-dimensional (3D) volumetric display system utilizing a rotating light-emitting diode (LED) array is presented, which provides viewers with true depth cues, binocular parallax, accommodation and convergence, etc, and can be observed from any direction without the need for any special viewing aids. The data voxelization method for the system is presented. The evaluation of texture distortion due to the deviations of the voxel positions caused in voxelization is introduced. 3D models with two types of texture are built: one in which the gray scale is nearly invariant in the background, and the other in which the gray scale varies in the whole picture. The texture distortion of models with the two types of texture is evaluated and a numerical analysis is given. The relationship between texture distortion and voxelization precision is studied. Voxelization precision can be improved by shortening the voxelization step length. Experiments show that models with textures in which gray scale varies gradually in the whole picture need higher voxelization precision than textures with an invariant gray scale background. In order to obtain similar display quality, the ratio of the voxelization step length of models with the two types of texture is about 5/2. This project was supported by the High-Tech Research and Development Program of China (2007AA01Z339).

  13. Potential applications of flat-panel volumetric CT in morphologic and functional small animal imaging.

    PubMed

    Greschus, Susanne; Kiessling, Fabian; Lichy, Matthias P; Moll, Jens; Mueller, Margareta M; Savai, Rajkumar; Rose, Frank; Ruppert, Clemens; Günther, Andreas; Luecke, Marcus; Fusenig, Norbert E; Semmler, Wolfhard; Traupe, Horst

    2005-08-01

    Noninvasive radiologic imaging has recently gained considerable interest in basic and preclinical research for monitoring disease progression and therapeutic efficacy. In this report, we introduce flat-panel volumetric computed tomography (fpVCT) as a powerful new tool for noninvasive imaging of different organ systems in preclinical research. The three-dimensional visualization that is achieved by isotropic high-resolution datasets is illustrated for the skeleton, chest, abdominal organs, and brain of mice. The high image quality of chest scans enables the visualization of small lung nodules in an orthotopic lung cancer model and the reliable imaging of therapy side effects such as lung fibrosis. Using contrast-enhanced scans, fpVCT displayed the vascular trees of the brain, liver, and kidney down to the subsegmental level. Functional application of fpVCT in dynamic contrast-enhanced scans of the rat brain delivered physiologically reliable data of perfusion and tissue blood volume. Beyond scanning of small animal models as demonstrated here, fpVCT provides the ability to image animals up to the size of primates.

  14. Sub-Nyquist Sampling and Fourier Domain Beamforming in Volumetric Ultrasound Imaging.

    PubMed

    Burshtein, Amir; Birk, Michael; Chernyakova, Tanya; Eilam, Alon; Kempinski, Arcady; Eldar, Yonina C

    2016-05-01

    A key step in ultrasound image formation is digital beamforming of signals sampled by several transducer elements placed upon an array. High-resolution digital beamforming introduces the demand for sampling rates significantly higher than the signals' Nyquist rate, which greatly increases the volume of data that must be transmitted from the system's front end. In 3-D ultrasound imaging, 2-D transducer arrays rather than 1-D arrays are used, and more scan lines are needed. This implies that the amount of sampled data is vastly increased with respect to 2-D imaging. In this work, we show that a considerable reduction in data rate can be achieved by applying the ideas of Xampling and frequency domain beamforming (FDBF), leading to a sub-Nyquist sampling rate, which uses only a portion of the bandwidth of the ultrasound signals to reconstruct the image. We extend previous work on FDBF for 2-D ultrasound imaging to accommodate the geometry imposed by volumetric scanning and a 2-D grid of transducer elements. High image quality from low-rate samples is demonstrated by simulation of a phantom image composed of several small reflectors. Our technique is then applied to raw data of a heart ventricle phantom obtained by a commercial 3-D ultrasound system. We show that by performing 3-D beamforming in the frequency domain, sub-Nyquist sampling and low processing rate are achievable, while maintaining adequate image quality.

  15. Enhanced gamma ray sensitivity in bismuth triiodide sensors through volumetric defect control

    SciTech Connect

    Johns, Paul M.; Baciak, James E.; Nino, Juan C.

    2016-08-29

    Some of the more attractive semiconducting compounds for ambient temperature radiation detector applications are impacted by low charge collection efficiency due to the presence of point and volumetric defects. This has been particularly true in the case of BiI{sub 3}, which features very attractive properties (density, atomic number, band gap, etc.) to serve as a gamma ray detector, but has yet to demonstrate its full potential. We show that by applying growth techniques tailored to reduce defects, the spectral performance of this promising semiconductor can be realized. Gamma ray spectra from >100 keV source emissions are now obtained from high quality Sb:BiI{sub 3} bulk crystals with limited concentrations of defects (point and extended). The spectra acquired in these high quality crystals feature photopeaks with resolution of 2.2% at 662 keV. Infrared microscopy is used to compare the local microstructure between radiation sensitive and non-responsive crystals. This work demonstrates that BiI{sub 3} can be prepared in melt-grown detector-grade samples with superior quality and can acquire the spectra from a variety of gamma ray sources.

  16. Tomographic Aperture-Encoded Particle Tracking Velocimetry: A New Approach to Volumetric PIV

    NASA Astrophysics Data System (ADS)

    Troolin, Dan; Boomsma, Aaron; Lai, Wing; Pothos, Stamatios; Fluid Mechanics Research Instruments Team

    2016-11-01

    Volumetric velocity fields are useful in a wide variety of fluid mechanics applications. Several types of three-dimensional imaging methods have been used in the past to varying degrees of success, for example, 3D PTV (Maas et al., 1993), DDPIV (Peireira et al., 2006), Tomographic PIV (Elsinga, 2006), and V3V (Troolin and Longmire, 2009), among others. Each of these techniques has shown advantages and disadvantages in different areas. With the advent of higher resolution and lower noise cameras with higher stability levels, new techniques are emerging that combine the advantages of the existing techniques. This talk describes a new technique called Tomographic Aperture-Encoded Particle Tracking Velocimetry (TAPTV), in which segmented triangulation and diameter tolerance are used to achieve three-dimensional particle tracking with extremely high particle densities (on the order of ppp = 0.2 or higher) without the drawbacks normally associated with ghost particles (for example in TomoPIV). The results are highly spatially-resolved data with very fast processing times. A detailed explanation of the technique as well as plots, movies, and experimental considerations will be discussed.

  17. Volumetric three-dimensional reconstruction and segmentation of spectral-domain OCT.

    PubMed

    Aaker, Grant D; Gracia, Luis; Myung, Jane S; Borcherding, Vanessa; Banfelder, Jason R; D'Amico, Donald J; Kiss, Szilárd

    2011-07-01

    Despite advances in optical coherence tomography (OCT), three-dimensional (3D) renderings of OCT images remain limited to scanning consecutive two-dimensional (2D) OCT slices. The authors describe a method of reconstructing 2D OCT data for 3D retinal analysis and visualization in a Computer Assisted Virtual Environment (CAVE). Using customized signal processing software, raw data from 2D slice-based spectral-domain OCT images were rendered into high-resolution 3D images for segmentation and quantification analysis. Reconstructed OCT images were projected onto a four-walled space and viewed through stereoscopic glasses, resulting in a virtual reality perception of the retina. These 3D retinal renderings offer a novel method for segmentation and isolation of volumetric images. The ability to manipulate the images in a virtual reality environment allows visualization of complex spatial relationships that may aid our understanding of retinal pathology. More importantly, these 3D retinal renderings can be viewed, manipulated, and analyzed on traditional 2D monitors independent of the CAVE.

  18. Genetic Dominance & Cellular Processes

    ERIC Educational Resources Information Center

    Seager, Robert D.

    2014-01-01

    In learning genetics, many students misunderstand and misinterpret what "dominance" means. Understanding is easier if students realize that dominance is not a mechanism, but rather a consequence of underlying cellular processes. For example, metabolic pathways are often little affected by changes in enzyme concentration. This means that…

  19. Genetic Dominance & Cellular Processes

    ERIC Educational Resources Information Center

    Seager, Robert D.

    2014-01-01

    In learning genetics, many students misunderstand and misinterpret what "dominance" means. Understanding is easier if students realize that dominance is not a mechanism, but rather a consequence of underlying cellular processes. For example, metabolic pathways are often little affected by changes in enzyme concentration. This means that…

  20. Cellular genetic therapy.

    PubMed

    Del Vecchio, F; Filareto, A; Spitalieri, P; Sangiuolo, F; Novelli, G

    2005-01-01

    Cellular genetic therapy is the ultimate frontier for those pathologies that are consequent to a specific nonfunctional cellular type. A viable cure for there kinds of diseases is the replacement of sick cells with healthy ones, which can be obtained from the same patient or a different donor. In fact, structures can be corrected and strengthened with the introduction of undifferentiated cells within specific target tissues, where they will specialize into the desired cellular types. Furthermore, consequent to the recent results obtained with the transdifferentiation experiments, a process that allows the in vitro differentiation of embryonic and adult stem cells, it has also became clear that many advantages may be obtained from the use of stem cells to produce drugs, vaccines, and therapeutic molecules. Since stem cells can sustain lineage potentials, the capacity for differentiation, and better tolerance for the introduction of exogenous genes, they are also considered as feasible therapeutic vehicles for gene therapy. In fact, it is strongly believed that the combination of cellular genetic and gene therapy approaches will definitely allow the development of new therapeutic strategies as well as the production of totipotent cell lines to be used as experimental models for the cure of genetic disorders.

  1. The New Cellular Immunology

    ERIC Educational Resources Information Center

    Claman, Henry N.

    1973-01-01

    Discusses the nature of the immune response and traces many of the discoveries that have led to the present state of knowledge in immunology. The new cellular immunology is directing its efforts toward improving health by proper manipulation of the immune mechanisms of the body. (JR)

  2. The New Cellular Immunology

    ERIC Educational Resources Information Center

    Claman, Henry N.

    1973-01-01

    Discusses the nature of the immune response and traces many of the discoveries that have led to the present state of knowledge in immunology. The new cellular immunology is directing its efforts toward improving health by proper manipulation of the immune mechanisms of the body. (JR)

  3. Conflict resolution.

    PubMed

    Levin, Roger

    2006-03-01

    The sooner conflict is identified and confronted, the more quickly it can be resolved (and the sooner, the better). When this is accomplished calmly and objectively, many areas of conflict will be eliminated. Addressing conflict as it arises also sends a clear message to the team that the practice seeks resolution, not punishment or negative consequences. In addition, the dentist and the office manager need to lead by example by avoiding gossip and encouraging open communication. The goal is to go from a parent-child relationship with the dental team to an adult-adult relationship using this series of managerial conflict resolution steps.

  4. Progressive Muscle Cell Delivery as a Solution for Volumetric Muscle Defect Repair

    PubMed Central

    Kim, Ji Hyun; Ko, In Kap; Atala, Anthony; Yoo, James J.

    2016-01-01

    Reconstructing functional volumetric tissue in vivo following implantation remains a critical challenge facing cell-based approaches. Several pre-vascularization approaches have been developed to increase cell viability following implantation. Structural and functional restoration was achieved in a preclinical rodent tissue defect; however, the approach used in this model fails to repair larger (>mm) defects as observed in a clinical setting. We propose an effective cell delivery system utilizing appropriate vascularization at the site of cell implantation that results in volumetric and functional tissue reconstruction. Our method of multiple cell injections in a progressive manner yielded improved cell survival and formed volumetric muscle tissues in an ectopic muscle site. In addition, this strategy supported the reconstruction of functional skeletal muscle tissue in a rodent volumetric muscle loss injury model. Results from our study suggest that our method may be used to repair volumetric tissue defects by overcoming diffusion limitations and facilitating adequate vascularization. PMID:27924941

  5. Global segmentation and curvature analysis of volumetric data sets using trivariate B-spline functions.

    PubMed

    Soldea, Octavian; Elber, Gershon; Rivlin, Ehud

    2006-02-01

    This paper presents a method to globally segment volumetric images into regions that contain convex or concave (elliptic) iso-surfaces, planar or cylindrical (parabolic) iso-surfaces, and volumetric regions with saddle-like (hyperbolic) iso-surfaces, regardless of the value of the iso-surface level. The proposed scheme relies on a novel approach to globally compute, bound, and analyze the Gaussian and mean curvatures of an entire volumetric data set, using a trivariate B-spline volumetric representation. This scheme derives a new differential scalar field for a given volumetric scalar field, which could easily be adapted to other differential properties. Moreover, this scheme can set the basis for more precise and accurate segmentation of data sets targeting the identification of primitive parts. Since the proposed scheme employs piecewise continuous functions, it is precise and insensitive to aliasing.

  6. Design, Implementation and Characterization of a Quantum-Dot-Based Volumetric Display

    NASA Astrophysics Data System (ADS)

    Hirayama, Ryuji; Naruse, Makoto; Nakayama, Hirotaka; Tate, Naoya; Shiraki, Atsushi; Kakue, Takashi; Shimobaba, Tomoyoshi; Ohtsu, Motoichi; Ito, Tomoyoshi

    2015-02-01

    In this study, we propose and experimentally demonstrate a volumetric display system based on quantum dots (QDs) embedded in a polymer substrate. Unlike conventional volumetric displays, our system does not require electrical wiring; thus, the heretofore unavoidable issue of occlusion is resolved because irradiation by external light supplies the energy to the light-emitting voxels formed by the QDs. By exploiting the intrinsic attributes of the QDs, the system offers ultrahigh definition and a wide range of colours for volumetric displays. In this paper, we discuss the design, implementation and characterization of the proposed volumetric display's first prototype. We developed an 8 × 8 × 8 display comprising two types of QDs. This display provides multicolour three-type two-dimensional patterns when viewed from different angles. The QD-based volumetric display provides a new way to represent images and could be applied in leisure and advertising industries, among others.

  7. Design, implementation and characterization of a quantum-dot-based volumetric display.

    PubMed

    Hirayama, Ryuji; Naruse, Makoto; Nakayama, Hirotaka; Tate, Naoya; Shiraki, Atsushi; Kakue, Takashi; Shimobaba, Tomoyoshi; Ohtsu, Motoichi; Ito, Tomoyoshi

    2015-02-16

    In this study, we propose and experimentally demonstrate a volumetric display system based on quantum dots (QDs) embedded in a polymer substrate. Unlike conventional volumetric displays, our system does not require electrical wiring; thus, the heretofore unavoidable issue of occlusion is resolved because irradiation by external light supplies the energy to the light-emitting voxels formed by the QDs. By exploiting the intrinsic attributes of the QDs, the system offers ultrahigh definition and a wide range of colours for volumetric displays. In this paper, we discuss the design, implementation and characterization of the proposed volumetric display's first prototype. We developed an 8 × 8 × 8 display comprising two types of QDs. This display provides multicolour three-type two-dimensional patterns when viewed from different angles. The QD-based volumetric display provides a new way to represent images and could be applied in leisure and advertising industries, among others.

  8. Enhanced volumetric visualization for real time 4D intraoperative ophthalmic swept-source OCT

    PubMed Central

    Viehland, Christian; Keller, Brenton; Carrasco-Zevallos, Oscar M.; Nankivil, Derek; Shen, Liangbo; Mangalesh, Shwetha; Viet, Du Tran; Kuo, Anthony N.; Toth, Cynthia A.; Izatt, Joseph A.

    2016-01-01

    Current-generation software for rendering volumetric OCT data sets based on ray casting results in volume visualizations with indistinct tissue features and sub-optimal depth perception. Recent developments in hand-held and microscope-integrated intrasurgical OCT designed for real-time volumetric imaging motivate development of rendering algorithms which are both visually appealing and fast enough to support real time rendering, potentially from multiple viewpoints for stereoscopic visualization. We report on an enhanced, real time, integrated volumetric rendering pipeline which incorporates high performance volumetric median and Gaussian filtering, boundary and feature enhancement, depth encoding, and lighting into a ray casting volume rendering model. We demonstrate this improved model implemented on graphics processing unit (GPU) hardware for real-time volumetric rendering of OCT data during tissue phantom and live human surgical imaging. We show that this rendering produces enhanced 3D visualizations of pathology and intraoperative maneuvers compared to standard ray casting. PMID:27231623

  9. High Volumetric Energy Density Hybrid Supercapacitors Based on Reduced Graphene Oxide Scrolls.

    PubMed

    Rani, Janardhanan R; Thangavel, Ranjith; Oh, Se-I; Woo, Jeong Min; Chandra Das, Nayan; Kim, So-Yeon; Lee, Yun-Sung; Jang, Jae-Hyung

    2017-07-12

    The low volumetric energy density of reduced graphene oxide (rGO)-based electrodes limits its application in commercial electrochemical energy storage devices that require high-performance energy storage capacities in small volumes. The volumetric energy density of rGO-based electrode materials is very low due to their low packing density. A supercapacitor with enhanced packing density and high volumetric energy density is fabricated using doped rGO scrolls (GFNSs) as the electrode material. The restacking of rGO sheets is successfully controlled through synthesizing the doped scroll structures while increasing the packing density. The fabricated cell exhibits an ultrahigh volumetric energy density of 49.66 Wh/L with excellent cycling stability (>10 000 cycles). This unique design strategy for the electrode material has significant potential for the future supercapacitors with high volumetric energy densities.

  10. Quantitative rainfall metrics for comparing volumetric rainfall retrievals to fine scale models

    NASA Astrophysics Data System (ADS)

    Collis, Scott; Tao, Wei-Kuo; Giangrande, Scott; Fridlind, Ann; Theisen, Adam; Jensen, Michael

    2013-04-01

    Precipitation processes play a significant role in the energy balance of convective systems for example, through latent heating and evaporative cooling. Heavy precipitation "cores" can also be a proxy for vigorous convection and vertical motions. However, comparisons between rainfall rate retrievals from volumetric remote sensors with forecast rain fields from high-resolution numerical weather prediction simulations are complicated by differences in the location and timing of storm morphological features. This presentation will outline a series of metrics for diagnosing the spatial variability and statistical properties of precipitation maps produced both from models and retrievals. We include existing metrics such as Contoured by Frequency Altitude Diagrams (Yuter and Houze 1995) and Statistical Coverage Products (May and Lane 2009) and propose new metrics based on morphology, cell and feature based statistics. Work presented focuses on observations from the ARM Southern Great Plains radar network consisting of three agile X-Band radar systems with a very dense coverage pattern and a C Band system providing site wide coverage. By combining multiple sensors resolutions of 250m2 can be achieved, allowing improved characterization of fine-scale features. Analyses compare data collected during the Midlattitude Continental Convective Clouds Experiment (MC3E) with simulations of observed systems using the NASA Unified Weather Research and Forecasting model. May, P. T., and T. P. Lane, 2009: A method for using weather radar data to test cloud resolving models. Meteorological Applications, 16, 425-425, doi:10.1002/met.150, 10.1002/met.150. Yuter, S. E., and R. A. Houze, 1995: Three-Dimensional Kinematic and Microphysical Evolution of Florida Cumulonimbus. Part II: Frequency Distributions of Vertical Velocity, Reflectivity, and Differential Reflectivity. Mon. Wea. Rev., 123, 1941-1963, doi:10.1175/1520-0493(1995)123<1941:TDKAME>2.0.CO;2.

  11. Biophysical Tools to Study Cellular Mechanotransduction

    PubMed Central

    Muhamed, Ismaeel; Chowdhury, Farhan; Maruthamuthu, Venkat

    2017-01-01

    The cell membrane is the interface that volumetrically isolates cellular components from the cell’s environment. Proteins embedded within and on the membrane have varied biological functions: reception of external biochemical signals, as membrane channels, amplification and regulation of chemical signals through secondary messenger molecules, controlled exocytosis, endocytosis, phagocytosis, organized recruitment and sequestration of cytosolic complex proteins, cell division processes, organization of the cytoskeleton and more. The membrane’s bioelectrical role is enabled by the physiologically controlled release and accumulation of electrochemical potential modulating molecules across the membrane through specialized ion channels (e.g., Na+, Ca2+, K+ channels). The membrane’s biomechanical functions include sensing external forces and/or the rigidity of the external environment through force transmission, specific conformational changes and/or signaling through mechanoreceptors (e.g., platelet endothelial cell adhesion molecule (PECAM), vascular endothelial (VE)-cadherin, epithelial (E)-cadherin, integrin) embedded in the membrane. Certain mechanical stimulations through specific receptor complexes induce electrical and/or chemical impulses in cells and propagate across cells and tissues. These biomechanical sensory and biochemical responses have profound implications in normal physiology and disease. Here, we discuss the tools that facilitate the understanding of mechanosensitive adhesion receptors. This article is structured to provide a broad biochemical and mechanobiology background to introduce a freshman mechano-biologist to the field of mechanotransduction, with deeper study enabled by many of the references cited herein.

  12. Volumetric brain analysis in neurosurgery: Part 3. Volumetric CT analysis as a predictor of seizure outcome following temporal lobectomy.

    PubMed

    Mandell, Jason G; Hill, Kenneth L; Nguyen, Dan T D; Moser, Kevin W; Harbaugh, Robert E; McInerney, James; Nsubuga, Brian Kaaya; Mugamba, John K; Johnson, Derek; Warf, Benjamin C; Boling, Warren; Webb, Andrew G; Schiff, Steven J

    2015-02-01

    The incidence of temporal lobe epilepsy (TLE) due to mesial temporal sclerosis (MTS) can be high in developing countries. Current diagnosis of MTS relies on structural MRI, which is generally unavailable in developing world settings. Given widespread effects on temporal lobe structure beyond hippocampal atrophy in TLE, the authors propose that CT volumetric analysis can be used in patient selection to help predict outcomes following resection. Ten pediatric patients received preoperative CT scans and temporal resections at the CURE Children's Hospital of Uganda. Engel classification of seizure control was determined 12 months postoperatively. Temporal lobe volumes were measured from CT and from normative MR images using the Cavalieri method. Whole brain and fluid volumes were measured using particle filter segmentation. Linear discrimination analysis (LDA) was used to classify seizure outcome by temporal lobe volumes and normalized brain volume. Epilepsy patients showed normal to small brain volumes and small temporal lobes bilaterally. A multivariate measure of the volume of each temporal lobe separated patients who were seizure free (Engel Class IA) from those with incomplete seizure control (Engel Class IB/IIB) with LDA (p<0.01). Temporal lobe volumes also separate normal subjects, patients with Engel Class IA outcomes, and patients with Class IB/IIB outcomes (p<0.01). Additionally, the authors demonstrated that age-normalized whole brain volume, in combination with temporal lobe volumes, may further improve outcome prediction (p<0.01). This study shows strong evidence that temporal lobe and brain volume can be predictive of seizure outcome following temporal lobe resection, and that volumetric CT analysis of the temporal lobe may be feasible in lieu of structural MRI when the latter is unavailable. Furthermore, since the authors' methods are modality independent, these findings suggest that temporal lobe and normative brain volumes may further be useful in the

  13. NCAI Resolutions

    ERIC Educational Resources Information Center

    American Indian Journal of the Institute for the Development of Indian Law, 1977

    1977-01-01

    Five Major Policy Resolutions were adopted, without objection, at the 33rd Annual Convention of the National Congress of American Indians (NCAI) held in Salt Lake City, Utah, in October 1976. The issues involved were: Treaties and Trust Responsibilities, Tribal Government, Jurisdiction, Federal Administration and Structure of Indian Affairs, and…

  14. STATIC VS PROSPECTIVE GATED, NON-BREATH HOLD VOLUMETRIC MDCT IMAGING OF THE LUNGS

    PubMed Central

    Saba, Osama I.; Chon, Deokiee; Beck, Kenneth; McLennan, Geoffrey; Sieren, Jered; Reinhardt, Joseph; Hoffman, Eric A.

    2005-01-01

    Rationale and Objectives: We seek to establish lung imaging methods which provide for the ability to image the lung under dynamic, non-breath hold conditions while providing “virtual breath hold,” quantifiable volumetric image data sets. We use static, breath hold images as the gold standard for evaluating these virtual breath hold images in both a phantom and sheep. Materials and Methods: We have developed axial methods for gating image acquisition to multiple points in the respiratory cycle interleaved with incremental table stepping during multidetector-row CT (MDCT) scanning. Datasets are generated over multiple breaths, providing volume images representative of multiple points within a respiratory cycle. To determine the reproducibility and accuracy of the methods , 6 anesthetized sheep were studied by MDCT in non-gated and airway-pressure (Pawy)-gated modes where Pawy was 0, 7 and 15 cmH2O. Results: No significant differences were found between the coefficient of variation in air volume measured from repeated static scans (1.74±1.78%), gated scans: Inspiratory gated (1.2±0.44%) or expiratory-gated (1.39±0.98%), or between static (1.74±1.78%) and gated (1.39+/-0.98%) scanning at similar Pawy (p>0.1). Measured air volumes were larger from static vs. gated scans by 5.85±3.77% at 7cmH2O and 4.45±3.6% at 15cmHL2O Pawy (p<0.05) consistent with hysteresis. Differences between air volumes at 7 and 15 cmH2O measured from either static or gated scans or that delivered by a supersyringe were insignificant (p<0.05). Visual accuracy of 3D anatomic geometry was achieved, and landmark certainty was within 1mm across respiratory cycles. Conclusion: A method has been demonstrated which provides for accurate gating to respiratory signals during axial scanning. High resolution volumetric image datasets are achievable while the scanned subject is breathing.Images are quantitatively similar to breath hold images with differences likely explained by known P-V hysteresis

  15. The new kid on the block for advanced imaging in Barrett's esophagus: a review of volumetric laser endomicroscopy.

    PubMed

    Trindade, Arvind J; Smith, Michael S; Pleskow, Douglas K

    2016-05-01

    Advanced imaging techniques used in the management of Barrett's esophagus include electronic imaging enhancement (e.g. narrow band imaging, flexible spectral imaging color enhancement, and i-Scan), chromoendoscopy, and confocal laser endomicroscopy. Electronic imaging enhancement is used frequently in daily practice, but use of the other advanced technologies is not routine. High-definition white light endoscopy and random four quadrant biopsy remain the standard of care for evaluation of Barrett's esophagus; this is largely due to the value of advanced imaging technologies not having been validated in large studies or in everyday practice. A new advanced imaging technology called volumetric laser endomicroscopy is commercially available in the United States. Its ease of use and rapid acquisition of high-resolution images make this technology very promising for widespread application. In this article we review the technology and its potential for advanced imaging in Barrett's esophagus.

  16. Single-shot, volumetrically illuminated, three-dimensional, tomographic laser-induced-fluorescence imaging in a gaseous free jet.

    PubMed

    Halls, Benjamin R; Thul, Daniel J; Michaelis, Dirk; Roy, Sukesh; Meyer, Terrence R; Gord, James R

    2016-05-02

    Single-shot, tomographic imaging of the three-dimensional concentration field is demonstrated in a turbulent gaseous free jet in co-flow using volumetrically illuminated laser-induced fluorescence. The fourth-harmonic output of an Nd:YAG laser at 266 nm is formed into a collimated 15 × 20 mm2 beam to excite the ground singlet state of acetone seeded into the central jet. Subsequent fluorescence is collected along eight lines of sight for tomographic reconstruction using a combination of stereoscopes optically coupled to four two-stage intensified CMOS cameras. The performance of the imaging system is evaluated and shown to be sufficient for recording instantaneous three-dimensional features with high signal-to-noise (130:1) and nominal spatial resolution of 0.6-1.5 mm at x/D = 7-15.5.

  17. Shaping volumetric light distribution through turbid media using real-time three-dimensional opto-acoustic feedback.

    PubMed

    Deán-Ben, X Luís; Estrada, Héctor; Razansky, Daniel

    2015-02-15

    Focusing light through turbid media represents a highly fascinating challenge in modern biophotonics. The unique capability of opto-acoustics for high-resolution imaging of light absorption contrast in deep tissues can provide a natural and efficient feedback to control light delivery in a scattering medium. While the basic feasibility of using opto-acoustic readings as a feedback mechanism for wavefront shaping has been recently reported, the suggested approaches may require long acquisition times, making them challenging to be translated into realistic tissue environments. In an attempt to significantly accelerate dynamic wavefront shaping capabilities, we present here a feedback-based approach using real-time three-dimensional opto-acoustic imaging assisted with genetic-algorithm-based optimization. The new technique offers robust performance in the presence of noisy measurements and can simultaneously control the scattered wave field in an entire volumetric region.

  18. Semi-Quantitative vs. Volumetric Determination of Endolymphatic Space in Menière’s Disease Using Endolymphatic Hydrops 3T-HR-MRI after Intravenous Gadolinium Injection

    PubMed Central

    Homann, Georg; Vieth, Volker; Weiss, Daniel; Nikolaou, Konstantin; Heindel, Walter; Notohamiprodjo, Mike; Böckenfeld, Yvonne

    2015-01-01

    Magnetic resonance imaging enhances the clinical diagnosis of Menière's disease. This is accomplished by in vivo detection of endolymphatic hydrops, which are graded using different semi-quantitative grading systems. We evaluated an established, semi-quantitative endolymphatic hydrops score and with a quantitative method for volumetric assessment of the endolymphatic size. 11 patients with Menière's disease and 2 healthy subjects underwent high resolution endolymphatic hydrops 3 Tesla MRI with highly T2 weighted FLAIR and T2DRIVE sequences. The degree of endolymphatic hydrops was rated semi-quantitatively and compared to the results of 3D-volumetry. Moreover, the grade of endolymphatic hydrops was correlated with pure tone audiometry. Semi-quantitative grading and volumetric evaluation of the endolymphatic hydrops are in accordance (r = 0.92) and the grade of endolymphatic hydrops correlates with pure tone audiometry. Patients with a sickness duration of ≥ 30 months showed a significant higher total labyrinth fluid volume (p = 0.03). Fast, semi-quantitative evaluation of endolymphatic hydrops is highly reliable compared to quantitative/volumetric assessment. Endolymphatic space is significantly higher in patients with longer sickness duration. PMID:25768940

  19. Using remote sensing for volumetric analyses of soil degradation by erosion

    NASA Astrophysics Data System (ADS)

    Vlacilova, Marketa; Krasa, Josef; Kavka, Petr

    2014-05-01

    Soil degradation by erosion can be effectively monitored or quantified by modern tools of remote sensing with variable level of detail accessible. The presented study deals with rill erosion assessment using stereoscopic images and orthophotos obtained by UAV (unmanned aerial vehicle). Advantages of UAVs are data in high resolution (1-10 cm/pixel), flexibility of data acquisition and price in comparison with standard aerial photography. Location attacked by intensive rainfall event in the spring 2013 was selected for this study of volumetric assessment of soil degradation by erosion. After the storm, rills and ephemeral gullies in different scales were detected on several fields in the target area. The study was focused on a single parcel catchment (12.5 ha) which attach to the main ephemeral gully in the monitored field. DEM of the location was obtained from UAV stereo images and official LIDAR data. At the same time, in-situ monitoring was effected for comparison and validation of methodology. The field measurement consisted of soil sampling and taking detailed stereo photographs of erosion rills. The photographs were processed by PhotoModeler Scanner software to obtain detailed surface data (TIN) of particular rills. The model for automatic and precise volumetric assessment of single rills was developed within ArcGIS. The whole study area DEM obtained from UAV was also analysed in ArcGIS using similar methodology for computation of rill volumes. The UAV DEM detected most rill bottoms and shapes however the level of detail was too low for actual sediment transport volume estimate. Therefore the volume obtained from UAV DEM was calibrated by the detailed models of single rills acquired by field measurement. Prior the calibration the UAV DEM volume was underestimated by 40-85% based on the rill size. Afterwards the target area was split into twelve separated regions defined by intensity and form of soil degradation (orthophoto-classified rill density). Equally, at

  20. Volumetric Changes of the Bezymianny Dome: Insights on the Eruptive Behavior

    NASA Astrophysics Data System (ADS)

    Ushakov, S. V.; Dvigalo, V. N.; Izbekov, P. E.

    2010-12-01

    Bezymianny Volcano, Kamchatka erupted explosively on March 30, 1956 after ca. 1000 period of quiescence. The collapse of the eastern flank of the volcano followed by a directed blast and 4-hour-long explosive activity excavated a 1.3x2.5 km horse-shoe crater open to the East. The eruption continued through extrusive activity, which by the end of the 1956 formed a 300-m-tall dome in the middle of the crater. The extrusive dome growth accompanied by frequent partial collapses and block-and-ash flows dominated through mid 70s, when short vigorous explosions from central vent followed by effusions of viscous lava flows gradually became the prevailed eruption mechanisms. The volumetric changes of the Bezymianny dome have been measured by routine aerial surveys and stereophotogrammetry since 1956. In early 90s the observations has been interrupted due to the lack of funding. Support from the PIRE-Kamchatka project allowed us to resume Bezymianny dome aerial surveys and make three consecutive measurements on June 31, 2006, September 5, 2009, and July 24, 2010. The acquired data was used to generate high resolution digital elevation models of the dome area and to determine morphological and volumetric changes in response to the most recent eruptive activity. Our observations indicate that by 2005-2006 a new crater formed at the summit of the dome. This crater served as a vent for each of seven explosive-effusive events that occurred during 2006-2010. Volumetric changes due to extrusive activity between early 90s and 2006 and during 2006-2010 have been minimal and only occurred in the crater area. At present the dome is entirely covered by lava flows and pyroclastic flow deposits erupted from the central vent. The average annual increase of the dome volume for the 2006-2010 period was 6.8x10^6 cubic meters. Pyroclastic deposits filled the area between the dome and the 1956 crater rim, elevated the flow of the 1956 crater, and reduced the height of the rim above the floor to

  1. Development and Evaluation of Real-Time Volumetric Compton Gamma-Ray Imaging

    NASA Astrophysics Data System (ADS)

    Barnowski, Ross Wegner

    An approach to gamma-ray imaging has been developed that enables near real-time volumetric (3D) imaging of unknown environments thus improving the utility of gamma-ray imaging for source-search and radiation mapping applications. The approach, herein dubbed scene data fusion (SDF), is based on integrating mobile radiation imagers with real time tracking and scene reconstruction algorithms to enable a mobile mode of operation and 3D localization of gamma-ray sources. The real-time tracking allows the imager to be moved throughout the environment or around a particular object of interest, obtaining the multiple perspectives necessary for standoff 3D imaging. A 3D model of the scene, provided in real-time by a simultaneous localization and mapping (SLAM) algorithm, can be incorporated into the image reconstruction reducing the reconstruction time and improving imaging performance. The SDF concept is demonstrated in this work with a Microsoft Kinect RGB-D sensor, a real-time SLAM solver, and two different mobile gamma-ray imaging platforms. The first is a cart-based imaging platform known as the Volumetric Compton Imager (VCI), comprising two 3D position-sensitive high purity germanium (HPGe) detectors, exhibiting excellent gamma-ray imaging characteristics, but with limited mobility due to the size and weight of the cart. The second system is the High Efficiency Multimodal Imager (HEMI) a hand-portable gamma-ray imager comprising 96 individual cm3 CdZnTe crystals arranged in a two-plane, active-mask configuration. The HEMI instrument has poorer energy and angular resolution than the VCI, but is truly hand-portable, allowing the SDF concept to be tested in multiple environments and for more challenging imaging scenarios. An iterative algorithm based on Compton kinematics is used to reconstruct the gamma-ray source distribution in all three spatial dimensions. Each of the two mobile imaging systems are used to demonstrate SDF for a variety of scenarios, including

  2. Predictability in cellular automata.

    PubMed

    Agapie, Alexandru; Andreica, Anca; Chira, Camelia; Giuclea, Marius

    2014-01-01

    Modelled as finite homogeneous Markov chains, probabilistic cellular automata with local transition probabilities in (0, 1) always posses a stationary distribution. This result alone is not very helpful when it comes to predicting the final configuration; one needs also a formula connecting the probabilities in the stationary distribution to some intrinsic feature of the lattice configuration. Previous results on the asynchronous cellular automata have showed that such feature really exists. It is the number of zero-one borders within the automaton's binary configuration. An exponential formula in the number of zero-one borders has been proved for the 1-D, 2-D and 3-D asynchronous automata with neighborhood three, five and seven, respectively. We perform computer experiments on a synchronous cellular automaton to check whether the empirical distribution obeys also that theoretical formula. The numerical results indicate a perfect fit for neighbourhood three and five, which opens the way for a rigorous proof of the formula in this new, synchronous case.

  3. Probabilistic cellular automata.

    PubMed

    Agapie, Alexandru; Andreica, Anca; Giuclea, Marius

    2014-09-01

    Cellular automata are binary lattices used for modeling complex dynamical systems. The automaton evolves iteratively from one configuration to another, using some local transition rule based on the number of ones in the neighborhood of each cell. With respect to the number of cells allowed to change per iteration, we speak of either synchronous or asynchronous automata. If randomness is involved to some degree in the transition rule, we speak of probabilistic automata, otherwise they are called deterministic. With either type of cellular automaton we are dealing with, the main theoretical challenge stays the same: starting from an arbitrary initial configuration, predict (with highest accuracy) the end configuration. If the automaton is deterministic, the outcome simplifies to one of two configurations, all zeros or all ones. If the automaton is probabilistic, the whole process is modeled by a finite homogeneous Markov chain, and the outcome is the corresponding stationary distribution. Based on our previous results for the asynchronous case-connecting the probability of a configuration in the stationary distribution to its number of zero-one borders-the article offers both numerical and theoretical insight into the long-term behavior of synchronous cellular automata.

  4. A synthetic diamond diode in volumetric modulated arc therapy dosimetry

    SciTech Connect

    Zani, Margherita; Bucciolini, Marta; Casati, Marta; Talamonti, Cinzia; Marinelli, Marco; Prestopino, Giuseppe; Tonnetti, Alessia; Verona-Rinati, Gianluca

    2013-09-15

    Purpose: The aim of this work is to investigate the behavior of a single crystal diamond diode (SCDD) for volumetric modulated arc therapy (VMAT) dose verifications. This delivery technique is one of the most severe test of a dosimeter performance due to the modulation of the dose rate achieved by simultaneously changing the velocity of the gantry and the position of the collimator leaves. The performed measurements with VMAT photon beams can therefore contribute to an overall global validation of the device to be used in dose distribution verifications.Methods: The SCDD response to 6 MVRX has been tested and compared with reference ionization chambers and treatment planning system (TPS) calculations in different experiments: (a) measurements of output factors for small field sizes (square fields of side ranging between 8 mm and 104 mm) by SCDD and A1SL ionization chamber; (b) angular dependence evaluation of the entire experimental set-up by SCDD, A1SL, and Farmer ionization chambers; and (c) acquisition of dose profiles for a VMAT treatment of a pulmonary disease in latero-lateral and gantry-target directions by SCDD and A1SL ionization chamber.Results: The output factors measured by SCDD favorably compare with the ones obtained by A1SL, whose response is affected by the lack of charged particle equilibrium and by averaging effect when small fields are involved. From the experiment on angular dependence, a good agreement is observed among the diamond diode, the ion chambers, and the TPS. In VMAT profiles, the absorbed doses measured by SCDD and A1SL compare well with the TPS calculated ones. An overall better agreement is observed in the case of the diamond dosimeter, which is also showing a better accuracy in terms of distance to agreement in the high gradient regions.Conclusions: Synthetic diamond diodes, whose performance were previously studied for conformal and IMRT radiotherapy techniques, were found to be suitable detectors also for dosimetric measurements

  5. Volumetric lean percentage measurement using dual energy mammography

    PubMed Central

    Ducote, Justin L.; Klopfer, Michael J.; Molloi, S.

    2011-01-01

    Purpose: Currently, there is no accepted standard for measuring breast density. Dual energy mammography, which has demonstrated accurate measurement in phantoms, has been proposed as one possible method. To examine the use of chemical analysis as a possible means to validate breast density measurements from dual energy mammography, a bovine tissue model was investigated. Known quantities of lean and adipose tissue were compared with composition values measured from dual energy images and chemical analysis. Methods: Theoretical simulations were performed to assess the impact variations in breast composition would have on measurement of breast density from a single calibration. Fourteen ex-vivo tissue samples composed of varying amounts of pure lean tissue and pure adipose tissue (lean percentage) from 0 to 100%, in increments of 10%, were imaged using dual energy mammography. This was followed by chemical analysis based on desiccation, trituration, and fat extraction with petroleum ether to determine water, lipid, and protein content. The volumetric lean percentage (VLP) as measured from images (VLPI) and as derived from chemical analysis data (VLPCA) were compared with the VLP calculated from measurements of sample mass with a scale (VLPM). Finally, data from the bovine tissue model in this study were compared to compositional data from a previous report of human tissue composition. Results: The results from simulation suggest a substantial impact on measuring breast density is likely due to changes in anatomical breast composition. VLPI was related to the VLPM by VLPI = 1.53 VLPM + 10.0 (r2>0.99). VLPCA was related to VLPM by VLPCA = 0.76 VLPM + 22.8 (r2>0.99). VLPI was related to VLPCA by VLPI = 2.00 VLPCA − 35.6 (r2>0.99). Bovine adipose tissue was shown to be very similar to human adipose tissue in terms of water, lipid, and protein content with RMS differences of 1.2%. Bovine lean tissue was shown to be very similar to human skeletal

  6. Hepatosplenic volumetric assessment at MDCT for staging liver fibrosis.

    PubMed

    Pickhardt, Perry J; Malecki, Kyle; Hunt, Oliver F; Beaumont, Claire; Kloke, John; Ziemlewicz, Timothy J; Lubner, Meghan G

    2017-07-01

    To investigate hepatosplenic volumetry at MDCT for non-invasive prediction of hepatic fibrosis. Hepatosplenic volume analysis in 624 patients (mean age, 48.8 years; 311 M/313 F) at MDCT was performed using dedicated software and compared against pathological fibrosis stage (F0 = 374; F1 = 48; F2 = 40; F3 = 65; F4 = 97). The liver segmental volume ratio (LSVR) was defined by Couinaud segments I-III over segments IV-VIII. All pre-cirrhotic fibrosis stages (METAVIR F1-F3) were based on liver biopsy within 1 year of MDCT. LSVR and total splenic volumes increased with stage of fibrosis, with mean(±SD) values of: F0: 0.26 ± 0.06 and 215.1 ± 88.5 mm(3); F1: 0.25 ± 0.08 and 294.8 ± 153.4 mm(3); F2: 0.331 ± 0.12 and 291.6 ± 197.1 mm(3); F3: 0.39 ± 0.15 and 509.6 ± 402.6 mm(3); F4: 0.56 ± 0.30 and 790.7 ± 450.3 mm(3), respectively. Total hepatic volumes showed poor discrimination (F0: 1674 ± 320 mm(3); F4: 1631 ± 691 mm(3)). For discriminating advanced fibrosis (≥F3), the ROC AUC values for LSVR, total liver volume, splenic volume and LSVR/spleen combined were 0.863, 0.506, 0.890 and 0.947, respectively. Relative changes in segmental liver volumes and total splenic volume allow for non-invasive staging of hepatic fibrosis, whereas total liver volume is a poor predictor. Unlike liver biopsy or elastography, these CT volumetric biomarkers can be obtained retrospectively on routine scans obtained for other indications. • Regional changes in hepatic volume (LSVR) correlate well with degree of fibrosis. • Total liver volume is a very poor predictor of underlying fibrosis. • Total splenic volume is associated with the degree of hepatic fibrosis. • Hepatosplenic volume assessment is comparable to elastography for staging fibrosis. • Unlike elastography, volumetric analysis can be performed retrospectively.

  7. Volumetric Spectroscopic Imaging of Glioblastoma Multiforme Radiation Treatment Volumes

    SciTech Connect

    Parra, N. Andres; Maudsley, Andrew A.; Gupta, Rakesh K.; Ishkanian, Fazilat; Huang, Kris; Walker, Gail R.; Padgett, Kyle; Roy, Bhaswati; Panoff, Joseph; Markoe, Arnold; Stoyanova, Radka

    2014-10-01

    Purpose: Magnetic resonance (MR) imaging and computed tomography (CT) are used almost exclusively in radiation therapy planning of glioblastoma multiforme (GBM), despite their well-recognized limitations. MR spectroscopic imaging (MRSI) can identify biochemical patterns associated with normal brain and tumor, predominantly by observation of choline (Cho) and N-acetylaspartate (NAA) distributions. In this study, volumetric 3-dimensional MRSI was used to map these compounds over a wide region of the brain and to evaluate metabolite-defined treatment targets (metabolic tumor volumes [MTV]). Methods and Materials: Volumetric MRSI with effective voxel size of ∼1.0 mL and standard clinical MR images were obtained from 19 GBM patients. Gross tumor volumes and edema were manually outlined, and clinical target volumes (CTVs) receiving 46 and 60 Gy were defined (CTV{sub 46} and CTV{sub 60}, respectively). MTV{sub Cho} and MTV{sub NAA} were constructed based on volumes with high Cho and low NAA relative to values estimated from normal-appearing tissue. Results: The MRSI coverage of the brain was between 70% and 76%. The MTV{sub NAA} were almost entirely contained within the edema, and the correlation between the 2 volumes was significant (r=0.68, P=.001). In contrast, a considerable fraction of MTV{sub Cho} was outside of the edema (median, 33%) and for some patients it was also outside of the CTV{sub 46} and CTV{sub 60}. These untreated volumes were greater than 10% for 7 patients (37%) in the study, and on average more than one-third (34.3%) of the MTV{sub Cho} for these patients were outside of CTV{sub 60}. Conclusions: This study demonstrates the potential usefulness of whole-brain MRSI for radiation therapy planning of GBM and revealed that areas of metabolically active tumor are not covered by standard RT volumes. The described integration of MTV into the RT system will pave the way to future clinical trials investigating outcomes in patients treated based on

  8. Volumetric imaging of oral epithelial neoplasia by MPM-SHGM: epithelial connective tissue interface (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Pal, Rahul; Yang, Jinping; Qiu, Suimin; Resto, Vicente; McCammon, Susan; Vargas, Gracie

    2016-03-01

    The majority of oral cancers are comprised of oral squamous cell carcinoma in which neoplastic epithelial cells invade across the epithelial connective tissue interface (ECTI). Invasion is preceded by a multi-component process including epithelial hyperproliferation, loss of cell polarity, and remodeling of the extracellular matrix. Multiphoton Autofluorescence Microscopy (MPAM) and Second Harmonic Generation Microscopy (SHGM) show promise for revealing indicators of neoplasia. In particular, volumetric imaging by these methods can reveal aspects of the 3D microstructure that are not possible by other methods and which could both further our understanding of neoplastic transformation and be explored for development of diagnostic approaches in this disease having only 55% 5-year survival rate. MPAM-SHG were applied to reveal the 3D structure of the critical ECTI interface that plays an integral part toward invasion. Epithelial dysplasia was induced in an established hamster model. MPAM-SHGM was applied to lesion sites, using 780 nm excitation (450-600nm emission) for autofluroescence of cellular and extracellular components; 840 nm using 420 nm bandpass filter for SHG. The ECTI surface was identified as the interface at which SHG signal began following the epithelium and was modeled as a 3D surface using Matlab. ECTI surface area and cell features at sites of epithelial expansion where ECTI was altered were measured; Imaged sites were biopsied and processed for histology. ROC analysis using ECTI image metrics indicated the ability to delineate normal from neoplasia with high sensitivity and specificity and it is noteworthy that inflammation did not significantly alter diagnostic potential of MPAM-SHGM .

  9. Rapid volumetric T1 mapping of the abdomen using three-dimensional through-time spiral GRAPPA.

    PubMed

    Chen, Yong; Lee, Gregory R; Aandal, Gunhild; Badve, Chaitra; Wright, Katherine L; Griswold, Mark A; Seiberlich, Nicole; Gulani, Vikas

    2016-04-01

    To develop an ultrafast T1 mapping method for high-resolution, volumetric T1 measurements in the abdomen. The Look-Locker method was combined with a stack-of-spirals acquisition accelerated using three-dimensional (3D) through-time spiral GRAPPA reconstruction for fast data acquisition. A segmented k-space acquisition scheme was proposed and the time delay between segments for the recovery of longitudinal magnetization was optimized using Bloch equation simulations. The accuracy of this method was validated in a phantom experiment and in vivo T1 measurements were performed with 35 asymptomatic subjects on both 1.5 Tesla (T) and 3T MRI systems. Phantom experiments yielded close agreement between the proposed method and gold standard measurements for a large range of T1 values (200 to 1600 ms). The in vivo results further demonstrate that high-resolution T1 maps (2 × 2 × 4 mm(3)) for 32 slices can be achieved in a single clinically feasible breath-hold of approximately 20 s. The T1 values for multiple organs and tissues in the abdomen are in agreement with the published literature. A high-resolution 3D abdominal T1 mapping technique was developed, which allows fast and accurate T1 mapping of multiple abdominal organs and tissues in a single breath-hold. © 2015 Wiley Periodicals, Inc.

  10. Is there a role for the use of volumetric cone beam computed tomography in periodontics?

    PubMed

    du Bois, A H; Kardachi, B; Bartold, P M

    2012-03-01

    Volumetric computed cone beam tomography offers a number of significant advantages over conventional intraoral and extraoral panoramic radiography, as well as computed tomography. To date, periodontal diagnosis has relied heavily on the assessment of both intraoral radiographs and extraoral panoramic radiographs. With emerging technology in radiology there has been considerable interest in the role that volumetric cone beam computed tomography might play in periodontal diagnostics. This narrative reviews the current evidence and considers whether there is a role for volumetric cone beam computed tomography in periodontics.

  11. In vivo volumetric imaging of biological dynamics in deep tissue via wavefront engineering

    PubMed Central

    Kong, Lingjie; Tang, Jianyong; Cui, Meng

    2016-01-01

    Biological systems undergo dynamical changes continuously which span multiple spatial and temporal scales. To study these complex biological dynamics in vivo, high-speed volumetric imaging that can work at large imaging depth is highly desired. However, deep tissue imaging suffers from wavefront distortion, resulting in reduced Strehl ratio and image quality. Here we combine the two wavefront engineering methods developed in our lab, namely the optical phase-locked ultrasound lens based volumetric imaging and the iterative multiphoton adaptive compensation technique, and demonstrate in vivo volumetric imaging of microglial and mitochondrial dynamics at large depth in mouse brain cortex and lymph node, respectively. PMID:26832504

  12. In vivo volumetric imaging of biological dynamics in deep tissue via wavefront engineering.

    PubMed

    Kong, Lingjie; Tang, Jianyong; Cui, Meng

    2016-01-25

    Biological systems undergo dynamical changes continuously which span multiple spatial and temporal scales. To study these complex biological dynamics in vivo, high-speed volumetric imaging that can work at large imaging depth is highly desired. However, deep tissue imaging suffers from wavefront distortion, resulting in reduced Strehl ratio and image quality. Here we combine the two wavefront engineering methods developed in our lab, namely the optical phase-locked ultrasound lens based volumetric imaging and the iterative multiphoton adaptive compensation technique, and demonstrate in vivo volumetric imaging of microglial and mitochondrial dynamics at large depth in mouse brain cortex and lymph node, respectively.

  13. Whole-cell, multicolor superresolution imaging using volumetric multifocus microscopy

    PubMed Central

    Hajj, Bassam; Wisniewski, Jan; El Beheiry, Mohamed; Chen, Jiji; Revyakin, Andrey; Wu, Carl; Dahan, Maxime

    2014-01-01

    Single molecule-based superresolution imaging has become an essential tool in modern cell biology. Because of the limited depth of field of optical imaging systems, one of the major challenges in superresolution imaging resides in capturing the 3D nanoscale morphology of the whole cell. Despite many previous attempts to extend the application of photo-activated localization microscopy (PALM) and stochastic optical reconstruction microscopy (STORM) techniques into three dimensions, effective localization depths do not typically exceed 1.2 µm. Thus, 3D imaging of whole cells (or even large organelles) still demands sequential acquisition at different axial positions and, therefore, suffers from the combined effects of out-of-focus molecule activation (increased background) and bleaching (loss of detections). Here, we present the use of multifocus microscopy for volumetric multicolor superresolution imaging. By simultaneously imaging nine different focal planes, the multifocus microscope instantaneously captures the distribution of single molecules (either fluorescent proteins or synthetic dyes) throughout an ∼4-µm-deep volume, with lateral and axial localization precisions of ∼20 and 50 nm, respectively. The capabilities of multifocus microscopy to rapidly image the 3D organization of intracellular structures are illustrated by superresolution imaging of the mammalian mitochondrial network and yeast microtubules during cell division. PMID:25422417

  14. Volumetric microscale particle tracking velocimetry (PTV) in porous media

    NASA Astrophysics Data System (ADS)

    Guo, Tianqi; Aramideh, Soroush; Ardekani, Arezoo M.; Vlachos, Pavlos P.

    2016-11-01

    The steady-state flow through refractive-index-matched glass bead microchannels is measured using microscopic particle tracking velocimetry (μPTV). A novel technique is developed to volumetrically reconstruct particles from oversampled two-dimensional microscopic images of fluorescent particles. Fast oversampling of the quasi-steady-state flow field in the lateral direction is realized by a nano-positioning piezo stage synchronized with a fast CMOS camera. Experiments at different Reynolds numbers are carried out for flows through a series of both monodispersed and bidispersed glass bead microchannels with various porosities. The obtained velocity fields at pore-scale (on the order of 10 μm) are compared with direct numerical simulations (DNS) conducted in the exact same geometries reconstructed from micro-CT scans of the glass bead microchannels. The developed experimental method would serve as a new approach for exploring the flow physics at pore-scale in porous media, and also provide benchmark measurements for validation of numerical simulations.

  15. Intuitive Exploration of Volumetric Data Using Dynamic Galleries.

    PubMed

    Jönsson, Daniel; Falk, Martin; Ynnerman, Anders

    2016-01-01

    In this work we present a volume exploration method designed to be used by novice users and visitors to science centers and museums. The volumetric digitalization of artifacts in museums is of rapidly increasing interest as enhanced user experience through interactive data visualization can be achieved. This is, however, a challenging task since the vast majority of visitors are not familiar with the concepts commonly used in data exploration, such as mapping of visual properties from values in the data domain using transfer functions. Interacting in the data domain is an effective way to filter away undesired information but it is difficult to predict where the values lie in the spatial domain. In this work we make extensive use of dynamic previews instantly generated as the user explores the data domain. The previews allow the user to predict what effect changes in the data domain will have on the rendered image without being aware that visual parameters are set in the data domain. Each preview represents a subrange of the data domain where overview and details are given on demand through zooming and panning. The method has been designed with touch interfaces as the target platform for interaction. We provide a qualitative evaluation performed with visitors to a science center to show the utility of the approach.

  16. Optical artefact characterization and correction in volumetric scintillation dosimetry

    PubMed Central

    Robertson, Daniel; Hui, Cheukkai; Archambault, Louis; Mohan, Radhe; Beddar, Sam

    2014-01-01

    The goals of this study were (1) to characterize the optical artefacts affecting measurement accuracy in a volumetric liquid scintillation detector, and (2) to develop methods to correct for these artefacts. The optical artefacts addressed were photon scattering, refraction, camera perspective, vignetting, lens distortion, the lens point spread function, stray radiation, and noise in the camera. These artefacts were evaluated by theoretical and experimental means, and specific correction strategies were developed for each artefact. The effectiveness of the correction methods was evaluated by comparing raw and corrected images of the scintillation light from proton pencil beams against validated Monte Carlo calculations. Blurring due to the lens and refraction at the scintillator tank-air interface were found to have the largest effect on the measured light distribution, and lens aberrations and vignetting were important primarily at the image edges. Photon scatter in the scintillator was not found to be a significant source of artefacts. The correction methods effectively mitigated the artefacts, increasing the average gamma analysis pass rate from 66% to 98% for gamma criteria of 2% dose difference and 2 mm distance to agreement. We conclude that optical artefacts cause clinically meaningful errors in the measured light distribution, and we have demonstrated effective strategies for correcting these optical artefacts. PMID:24321820

  17. Optical artefact characterization and correction in volumetric scintillation dosimetry

    NASA Astrophysics Data System (ADS)

    Robertson, Daniel; Hui, Cheukkai; Archambault, Louis; Mohan, Radhe; Beddar, Sam

    2014-01-01

    The goals of this study were (1) to characterize the optical artefacts affecting measurement accuracy in a volumetric liquid scintillator detector, and (2) to develop methods to correct for these artefacts. The optical artefacts addressed were photon scattering, refraction, camera perspective, vignetting, lens distortion, the lens point spread function, stray radiation, and noise in the camera. These artefacts were evaluated by theoretical and experimental means, and specific correction strategies were developed for each artefact. The effectiveness of the correction methods was evaluated by comparing raw and corrected images of the scintillation light from proton pencil beams against validated Monte Carlo calculations. Blurring due to the lens and refraction at the scintillator tank-air interface were found to have the largest effect on the measured light distribution, and lens aberrations and vignetting were important primarily at the image edges. Photon scatter in the scintillator was not found to be a significant source of artefacts. The correction methods effectively mitigated the artefacts, increasing the average gamma analysis pass rate from 66% to 98% for gamma criteria of 2% dose difference and 2 mm distance to agreement. We conclude that optical artefacts cause clinically meaningful errors in the measured light distribution, and we have demonstrated effective strategies for correcting these optical artefacts.

  18. Laser beam steering via wave mixing in volumetric thermal gratings

    NASA Astrophysics Data System (ADS)

    Tyler, David W.

    1992-06-01

    A volumetric thermal grating (VTG) is a spatially periodic refractive index variation in a volume of gas or liquid, generated by imaging interference fringes into the medium. The fringes can be created and varied by steering laser write beams electronically with acousto- optic (A-O) cells. While the wavelength of the write beams is chosen to be absorbed by a dopant in the VTG medium, a read beam at an off-resonance wavelength can be manipulated by diffraction from the resulting index grating. Potential applications include resonator and amplifier optical isolation prepulse suppression in high-gain amplifiers, noninertial steering of large-diameter laser beams, transfer of phase information between beams to facilitate adaptive optics, Q-switching of chemical lasers, and line selection in broadband lasers. In this paper, we present a preliminary assessment of VTG utility for these optical systems applications by quantitative analysis of the medium density dynamics. In Section 2, we derive a relation between A-O acoustic frequency uncertainty and VTG pointing/steering uncertainty, which also scales desired steering range to required A-O frequency modulation bandwidth. In Section 3, we discuss the temporal response of a doped rare-gas VTG medium. Section 4 is an assessment of VTG beam-steering performance potential using available technology.

  19. Volumetric PIV in Patient-Specific Cerebral Aneurysm

    NASA Astrophysics Data System (ADS)

    Brindise, Melissa; Dickerhoff, Ben; Saloner, David; Rayz, Vitaliy; Vlachos, Pavlos

    2016-11-01

    Cerebral aneurysms impose a unique challenge in which neurosurgeons must assess and decide between the risk of rupture and risk of treatment for each patient. Risk of rupture is often difficult to determine and most commonly assessed using geometric data including the size and shape of the aneurysm and parent vessel. Hemodynamics is thought to play a major role in the growth and rupture of a cerebral aneurysm, but its specific influence is largely unknown due to the inability of in vivo modalities to characterize detailed flow fields and limited in vitro studies. In this work, we use a patient-specific basilar tip aneurysm model and volumetric particle image velocimetry (PIV). In vivo, 4-D PC-MRI measurements were obtained for this aneurysm and the extracted pulsatile waveform was used for the in vitro study. Clinically relevant metrics including wall shear stress (WSS), oscillatory shear index (OSI), relative residence time (RRT), 3-D pressure contours, and pressure wave speed were subsequently computed. This is the first study to investigate in vitro 3-D pressure fields within a cerebral aneurysm. The results of this study demonstrate how these metrics influence the biomechanics of the aneurysm and ultimately their affect on the risk of rupture.

  20. Volumetric applications for spiral CT in the thorax

    NASA Astrophysics Data System (ADS)

    Rubin, Geoffrey D.; Napel, Sandy; Leung, Ann N.

    1994-05-01

    Spiral computed tomography (CT) is a new technique for rapidly acquiring volumetric data within the body. By combining a continuous gantry rotation and table feed, it is possible to image the entire thorax within a single breath-hold. This eliminates the ventilatory misregistration seen with conventional thoracic CT, which can result in small pulmonary lesions being undetected. An additional advantage of a continuous data set is that axial sections can be reconstructed at arbitrary intervals along the spiral path, resulting in the generation of overlapping sections which diminish partial volume effects resulting from lesions that straddle adjacent sections. The rapid acquisition of spiral CT enables up to a 50% reduction in the total iodinated contrast dose required for routine thoracic CT scanning. This can be very important for imaging patients with cardiac and renal diseases and could reduce the cost of thoracic CT scanning. Alternatively, by combining a high flow peripheral intravenous iodinated contrast injection with a spiral CT acquisition, it is possible to obtain images of the vasculature, which demonstrate pulmonary arterial thrombi, aortic aneurysms and dissections, and congenital vascular anomalies in detail previously unattainable without direct arterial access.

  1. Volumetric Security Alarm Based on a Spherical Ultrasonic Transducer Array

    NASA Astrophysics Data System (ADS)

    Sayin, Umut; Scaini, Davide; Arteaga, Daniel

    Most of the existent alarm systems depend on physical or visual contact. The detection area is often limited depending on the type of the transducer, creating blind spots. Our proposition is a truly volumetric alarm system that can detect any movement in the intrusion area, based on monitoring the change over time of the impulse response of the room, which acts as an acoustic footprint. The device depends on an omnidirectional ultrasonic transducer array emitting sweep signals to calculate the impulse response in short intervals. Any change in the room conditions is monitored through a correlation function. The sensitivity of the alarm to different objects and different environments depends on the sweep duration, sweep bandwidth, and sweep interval. Successful detection of intrusions also depends on the size of the monitoring area and requires an adjustment of emitted ultrasound power. Strong air flow affects the performance of the alarm. A method for separating moving objects from strong air flow is devised using an adaptive thresholding on the correlation function involving a series of impulse response measurements. The alarm system can be also used for fire detection since air flow sourced from heating objects differ from random nature of the present air flow. Several measurements are made to test the integrity of the alarm in rooms sizing from 834-2080m3 with irregular geometries and various objects. The proposed system can efficiently detect intrusion whilst adequate emitting power is provided.

  2. Ice volumetric changes on active volcanoes in southern Chile

    NASA Astrophysics Data System (ADS)

    Rivera, Andrés; Bown, Francisca; Mella, Ronald; Wendt, Jens; Casassa, Gino; Acuña, César; Rignot, Eric; Clavero, Jorge; Brock, Benjamin

    Most of the glaciers in southern Chile have been retreating and shrinking during recent decades in response to atmospheric warming and decrease in precipitation. However, some glacier fluctuations are directly associated with the effusive and geothermal activity of ice-covered active volcanoes widely distributed in the region. The aim of this paper is to study the ice volumetric changes by comparing several topographic datasets. A maximum mean ice thinning rate of 0.81 ± 0.45 m a-1 was observed on the ash/debris-covered ablation area of Volcán Villarrica between 1961 and 2004, whilst on Volcán Mocho the signal-to-noise ratio was too small to yield any conclusion. An area reduction of 0.036 ± 0.019 km2 a-1 since 1976 was obtained on Glaciar Mocho, while on Volcán Villarrica the area change was -0.090 ± 0.034 km2 a-1 between 1976 and 2005. Glaciers on active volcanoes are therefore shrinking, mainly in response to climatic driving factors. However, volcanic activity is affecting glaciers in two opposite ways: ash/debris advection is helping to reduce surface ablation at lower reaches by insulating the ice from solar radiation, while geothermal activity is probably enhancing melting and water production at the bedrock, resulting in negative ice-elevation changes.

  3. Quality assurance of volumetric modulated arc therapy using Elekta Synergy.

    PubMed

    Haga, Akihiro; Nakagawa, Keiichi; Shiraishi, Kenshiro; Itoh, Saori; Terahara, Atsuro; Yamashita, Hideomi; Ohtomo, Kuni; Saegusa, Shigeki; Imae, Toshikazu; Yoda, Kiyoshi; Pellegrini, Roberto

    2009-01-01

    PURPOSE. Recently, Elekta has supplied volumetric modulated arc therapy (VMAT) in which multi-leaf collimator (MLC) shape, jaw position, collimator angle, and gantry speed vary continuously during gantry rotation. A quality assurance procedure for VMAT delivery is described. METHODS AND MATERIALS. A single-arc VMAT plan with 73 control points (CPs) and 5-degree gantry angle spacing for a prostate cancer patient has been created by ERGO + + treatment planning system (TPS), where MLC shapes are given by anatomic relationship between a target and organs at risk and the monitor unit for each CP is optimized based on given dose prescriptions. Actual leaf and jaw positions, gantry angles and dose rates during prostate VMAT delivery were recorded in every 0.25 seconds, and the errors between planned and actual values were evaluated. The dose re-calculation using these recorded data has been performed and compared with the original TPS plan using the gamma index. RESULTS. Typical peak errors of gantry angles, leaf positions, and jaw positions were 3 degrees, 0.6 mm, and 1 mm, respectively. The dose distribution obtained by the TPS plan and the recalculated one agreed well under 2%-2 mm gamma index criteria. CONCLUSIONS. Quality assurance for prostate VMAT delivery has been performed with a satisfied result.

  4. Volumetric Survey Speed: A Figure of Merit for Transient Surveys

    NASA Astrophysics Data System (ADS)

    Bellm, Eric C.

    2016-08-01

    Time-domain surveys can exchange sky coverage for revisit frequency, complicating the comparison of their relative capabilities. By using different revisit intervals, a specific camera may execute surveys optimized for discovery of different classes of transient objects. We propose a new figure of merit, the instantaneous volumetric survey speed, for evaluating transient surveys. This metric defines the trade between cadence interval and snapshot survey volume and so provides a natural means of comparing survey capability. The related metric of areal survey speed imposes a constraint on the range of possible revisit times: we show that many modern time-domain surveys are limited by the amount of fresh sky available each night. We introduce the concept of “spectroscopic accessibility” and discuss its importance for transient science goals requiring followup observing. We present an extension of the control time algorithm for cases where multiple consecutive detections are required. Finally, we explore how survey speed and choice of cadence interval determine the detection rate of transients in the peak absolute magnitude-decay timescale phase space.

  5. Solenoidal filtering of volumetric velocity measurements using Gaussian process regression

    NASA Astrophysics Data System (ADS)

    Azijli, Iliass; Dwight, Richard P.

    2015-11-01

    Volumetric velocity measurements of incompressible flows contain spurious divergence due to measurement noise, despite mass conservation dictating that the velocity field must be divergence-free (solenoidal). We investigate the use of Gaussian process regression to filter spurious divergence, returning analytically solenoidal velocity fields. We denote the filter solenoidal Gaussian process regression (SGPR) and formulate it within the Bayesian framework to allow a natural inclusion of measurement uncertainty. To enable efficient handling of large data sets on regular and near-regular grids, we propose a solution procedure that exploits the Toeplitz structure of the system matrix. We apply SGPR to two synthetic and two experimental test cases and compare it with two other recently proposed solenoidal filters. For the synthetic test cases, we find that SGPR consistently returns more accurate velocity, vorticity and pressure fields. From the experimental test cases, we draw two important conclusions. Firstly, it is found that including an accurate model for the local measurement uncertainty further improves the accuracy of the velocity field reconstructed with SGPR. Secondly, it is found that all solenoidal filters result in an improved reconstruction of the pressure field, as verified with microphone measurements. The results obtained with SGPR are insensitive to correlation length, demonstrating the robustness of the filter to its parameters.

  6. Illustration-inspired depth enhanced volumetric medical visualization.

    PubMed

    Svakhine, Nikolai A; Ebert, David S; Andrews, William M

    2009-01-01

    Volume illustration can be used to provide insight into source data from CT/MRI scanners in much the same way as medical illustration depicts the important details of anatomical structures. As such, proven techniques used in medical illustration should be transferable to volume illustration, providing scientists with new tools to visualize their data. In recent years, a number of techniques have been developed to enhance the rendering pipeline and create illustrative effects similar to the ones found in medical textbooks and surgery manuals. Such effects usually highlight important features of the subject while subjugating its context and providing depth cues for correct perception. Inspired by traditional visual and line-drawing techniques found in medical illustration, we have developed a collection of fast algorithms for more effective emphasis/de-emphasis of data as well as conveyance of spatial relationships. Our techniques utilize effective outlining techniques and selective depth enhancement to provide perceptual cues of object importance as well as spatial relationships in volumetric datasets. Moreover, we have used illustration principles to effectively combine and adapt basic techniques so that they work together to provide consistent visual information and a uniform style.

  7. Surface-Constrained Volumetric Brain Registration Using Harmonic Mappings

    PubMed Central

    Joshi, Anand A.; Shattuck, David W.; Thompson, Paul M.; Leahy, Richard M.

    2015-01-01

    In order to compare anatomical and functional brain imaging data across subjects, the images must first be registered to a common coordinate system in which anatomical features are aligned. Intensity-based volume registration methods can align subcortical structures well, but the variability in sulcal folding patterns typically results in misalignment of the cortical surface. Conversely, surface-based registration using sulcal features can produce excellent cortical alignment but the mapping between brains is restricted to the cortical surface. Here we describe a method for volumetric registration that also produces an accurate one-to-one point correspondence between cortical surfaces. This is achieved by first parameterizing and aligning the cortical surfaces using sulcal landmarks. We then use a constrained harmonic mapping to extend this surface correspondence to the entire cortical volume. Finally, this mapping is refined using an intensity-based warp. We demonstrate the utility of the method by applying it to T1-weighted magnetic resonance images (MRI). We evaluate the performance of our proposed method relative to existing methods that use only intensity information; for this comparison we compute the inter-subject alignment of expert-labeled sub-cortical structures after registration. PMID:18092736

  8. Volumetric analysis of aeration in the lungs during general anaesthesia.

    PubMed

    Reber, A; Engberg, G; Sporre, B; Kviele, L; Rothen, H U; Wegenius, G; Nylund, U; Hedenstierna, G

    1996-06-01

    Spiral computed tomography (CT) allows volumetric analysis of formation of atelectasis and aeration of the lungs during anaesthesia. We studied 26 premedicated patients undergoing elective surgery allocated to group 1 (conscious, spontaneous breathing, investigating inspiration and expiration), group 2 (general anaesthesia with mechanical ventilation, investigating inspiration and expiration) or group 3 (general anaesthesia with mechanical ventilation, investigating changes over time). Using spiral CT, the lungs were studied either before or during general anaesthesia. CT scans were grouped into the following areas: overaeration, normal aeration, reduced aeration, poor aeration and atelectasis. The mechanism of atelectasis appeared to be both gravitational forces and a diaphragm-related force that acts regionally in caudal lung regions. Mean atelectasis formation and poorly aerated regions comprised approximately 4% of the total lung volume between the diaphragm and carina, giving a mean value of 16-20% of the normal aerated lung tissue being either collapsed or poorly aerated. The vertical ventilation distribution was more even during anaesthesia than in the awake state.

  9. Intravital microscopy: new insights into cellular interactions.

    PubMed

    Gavins, Felicity N E

    2012-10-01

    Inflammation is the body's way of combating invading pathogens or noxious stimuli. Under normal conditions, the complex host response of rubor, dolor, calor, tumor, and functio laesa is essential for survival and the return to homeostasis. However, unregulated inflammation is all too often observed in diseases such as rheumatoid arthritis, stroke, and cancer. The host inflammatory response is governed by a number of tightly regulated processes that enable cellular trafficking to occur at the sites of damage to ultimately ensure the resolution of inflammation. Intravital microscopy (IVM) provides quantitative, qualitative, and dynamic insights into cell biology and these cellular interactions. This review highlights the pros and cons of this specialized technique and how it has evolved to help understand the physiology and pathophysiology of inflammatory events in a number of different disease states, leading to a number of potential therapeutic targets for drug discovery. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Line-Focused Optical Excitation of Parallel Acoustic Focused Sample Streams for High Volumetric and Analytical Rate Flow Cytometry.

    PubMed

    Kalb, Daniel M; Fencl, Frank A; Woods, Travis A; Swanson, August; Maestas, Gian C; Juárez, Jaime J; Edwards, Bruce S; Shreve, Andrew P; Graves, Steven W

    2017-09-19

    Flow cytometry provides highly sensitive multiparameter analysis of cells and particles but has been largely limited to the use of a single focused sample stream. This limits the analytical rate to ∼50K particles/s and the volumetric rate to ∼250 μL/min. Despite the analytical prowess of flow cytometry, there are applications where these rates are insufficient, such as rare cell analysis in high cellular backgrounds (e.g., circulating tumor cells and fetal cells in maternal blood), detection of cells/particles in large dilute samples (e.g., water quality, urine analysis), or high-throughput screening applications. Here we report a highly parallel acoustic flow cytometer that uses an acoustic standing wave to focus particles into 16 parallel analysis points across a 2.3 mm wide optical flow cell. A line-focused laser and wide-field collection optics are used to excite and collect the fluorescence emission of these parallel streams onto a high-speed camera for analysis. With this instrument format and fluorescent microsphere standards, we obtain analysis rates of 100K/s and flow rates of 10 mL/min, while maintaining optical performance comparable to that of a commercial flow cytometer. The results with our initial prototype instrument demonstrate that the integration of key parallelizable components, including the line-focused laser, particle focusing using multinode acoustic standing waves, and a spatially arrayed detector, can increase analytical and volumetric throughputs by orders of magnitude in a compact, simple, and cost-effective platform. Such instruments will be of great value to applications in need of high-throughput yet sensitive flow cytometry analysis.

  11. Cellular Communication through Light

    PubMed Central

    Fels, Daniel

    2009-01-01

    Information transfer is a fundamental of life. A few studies have reported that cells use photons (from an endogenous source) as information carriers. This study finds that cells can have an influence on other cells even when separated with a glass barrier, thereby disabling molecule diffusion through the cell-containing medium. As there is still very little known about the potential of photons for intercellular communication this study is designed to test for non-molecule-based triggering of two fundamental properties of life: cell division and energy uptake. The study was performed with a cellular organism, the ciliate Paramecium caudatum. Mutual exposure of cell populations occurred under conditions of darkness and separation with cuvettes (vials) allowing photon but not molecule transfer. The cell populations were separated either with glass allowing photon transmission from 340 nm to longer waves, or quartz being transmittable from 150 nm, i.e. from UV-light to longer waves. Even through glass, the cells affected cell division and energy uptake in neighboring cell populations. Depending on the cuvette material and the number of cells involved, these effects were positive or negative. Also, while paired populations with lower growth rates grew uncorrelated, growth of the better growing populations was correlated. As there were significant differences when separating the populations with glass or quartz, it is suggested that the cell populations use two (or more) frequencies for cellular information transfer, which influences at least energy uptake, cell division rate and growth correlation. Altogether the study strongly supports a cellular communication system, which is different from a molecule-receptor-based system and hints that photon-triggering is a fine tuning principle in cell chemistry. PMID:19340303

  12. Formin’ cellular structures

    PubMed Central

    Bogdan, Sven; Schultz, Jörg; Grosshans, Jörg

    2014-01-01

    Members of the Diaphanous (Dia) protein family are key regulators of fundamental actin driven cellular processes, which are conserved from yeast to humans. Researchers have uncovered diverse physiological roles in cell morphology, cell motility, cell polarity, and cell division, which are involved in shaping cells into tissues and organs. The identification of numerous binding partners led to substantial progress in our understanding of the differential functions of Dia proteins. Genetic approaches and new microscopy techniques allow important new insights into their localization, activity, and molecular principles of regulation. PMID:24719676

  13. Ultradiscrete Systems (Cellular Automata)

    NASA Astrophysics Data System (ADS)

    Tokihiro, Tetsuji

    Ultradiscretization is a limiting procedure which allows one to obtain a cellular automaton (CA) from continuous equations. Using this method, we can construct integrable CAs from integrable partial difference equations. In this course, we focus on a typical integrable CA, called a Box and Ball system (BBS), and review its peculiar features. Since a BBS is an ultradiscrete limit of the discrete KP equation and discrete Toda equation, we can obtain explicit solutions and conserved quantities for the BBS. Furthermore the BBS is also regarded as a limit (crystallization) of an integrable lattice model. Recent topics, and a periodic BBS in particular are also reviewed.

  14. Review of cellular mechanotransduction

    NASA Astrophysics Data System (ADS)

    Wang, Ning

    2017-06-01

    Living cells and tissues experience physical forces and chemical stimuli in the human body. The process of converting mechanical forces into biochemical activities and gene expression is mechanochemical transduction or mechanotransduction. Significant advances have been made in understanding mechanotransduction at the cellular and molecular levels over the last two decades. However, major challenges remain in elucidating how a living cell integrates signals from mechanotransduction with chemical signals to regulate gene expression and to generate coherent biological responses in living tissues in physiological conditions and diseases.

  15. Cellular mechanics and motility

    NASA Astrophysics Data System (ADS)

    Hénon, Sylvie; Sykes, Cécile

    2015-10-01

    The term motility defines the movement of a living organism. One widely known example is the motility of sperm cells, or the one of flagellar bacteria. The propulsive element of such organisms is a cilium(or flagellum) that beats. Although cells in our tissues do not have a flagellum in general, they are still able to move, as we will discover in this chapter. In fact, in both cases of movement, with or without a flagellum, cell motility is due to a dynamic re-arrangement of polymers inside the cell. Let us first have a closer look at the propulsion mechanism in the case of a flagellum or a cilium, which is the best known, but also the simplest, and which will help us to define the hydrodynamic general conditions of cell movement. A flagellum is sustained by cellular polymers arranged in semi-flexible bundles and flagellar beating generates cell displacement. These polymers or filaments are part of the cellular skeleton, or "cytoskeleton", which is, in this case, external to the cellular main body of the organism. In fact, bacteria move in a hydrodynamic regime in which viscosity dominates over inertia. The system is thus in a hydrodynamic regime of low Reynolds number (Box 5.1), which is nearly exclusively the case in all cell movements. Bacteria and their propulsion mode by flagella beating are our unicellular ancestors 3.5 billion years ago. Since then, we have evolved to form pluricellular organisms. However, to keep the ability of displacement, to heal our wounds for example, our cells lost their flagellum, since it was not optimal in a dense cell environment: cells are too close to each other to leave enough space for the flagella to accomplish propulsion. The cytoskeleton thus developed inside the cell body to ensure cell shape changes and movement, and also mechanical strength within a tissue. The cytoskeleton of our cells, like the polymers or filaments that sustain the flagellum, is also composed of semi-flexible filaments arranged in bundles, and also in

  16. Oral Cellular Neurothekeoma

    PubMed Central

    Emami, Nader; Zawawi, Faisal; Ywakim, Rania; Daniel, Sam J.

    2013-01-01

    Cellular neurothekeoma is known as a cutaneous tumor with uncertain histogenesis. Very little involvement of mucosal membrane has been reported in the literature so far. This is a case report of an intraoral lesion in a 15-years-old girl. Histopathologic evaluation showed a tumor-consists of spindle to epitheloid cells forming micronodules in a concentric whorled shape pattern. Tumor cells were positive for CD63, vimentin, and NKI-C3. Total excision was performed and no recurrence happened after 16-month followup. PMID:23691398

  17. Cellular Analogs of Operant Behavior

    DTIC Science & Technology

    1990-12-31

    activity rather than by a cellular reinforcement process. We have always required as critical evidence of cellular reinforcement that noncontingent or... reinforcement process. We have always required as critical evidence of cellular reinforcement that noncortingent or random presentations of the positive...the burst- ing of hippocampal pyramidal cells. One approach is to attempt to reinforce hippocamp- al bursting with a nonspecific depolarizing agent

  18. Multifunctional periodic cellular metals.

    PubMed

    Wadley, Haydn N G

    2006-01-15

    Periodic cellular metals with honeycomb and corrugated topologies are widely used for the core