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Sample records for cellular resolution volumetric

  1. Cellular resolution volumetric in vivo retinal imaging with adaptive optics–optical coherence tomography◊

    PubMed Central

    Zawadzki, Robert J.; Choi, Stacey S.; Fuller, Alfred R.; Evans, Julia W.; Hamann, Bernd; Werner, John S.

    2009-01-01

    Ultrahigh-resolution adaptive optics–optical coherence tomography (UHR-AO-OCT) instrumentation allowing monochromatic and chromatic aberration correction was used for volumetric in vivo retinal imaging of various retinal structures including the macula and optic nerve head (ONH). Novel visualization methods that simplify AO-OCT data viewing are presented, and include co-registration of AO-OCT volumes with fundus photography and stitching of multiple AO-OCT sub-volumes to create a large field of view (FOV) high-resolution volume. Additionally, we explored the utility of Interactive Science Publishing by linking all presented AO-OCT datasets with the OSA ISP software. PMID:19259248

  2. A model for the volumetric radiation characteristics of cellular ceramics

    SciTech Connect

    Fu, X.; Viskanta, R.; Gore, J.P.

    1997-12-01

    A unit cell based model for cellular ceramics was developed in conjunction with the discrete ordinates method for radiative transfer to predict theoretically the effective volumetric radiation characteristics of the cellular ceramics. Model input parameters include the porosity, pores per centimeter (PPC) and reflectivity of the solid material. Numerical calculations of the extinction coefficients and single scattering albedo are reported over the range of reflectivities from 0 to 1, porosities from 0.6 to 0.95 and PPC from 4 to 26. A comparison between model predictions and spectral emittance data for cellular ceramics reported in the literature shows agreement within 5 to 10% which is within experimental uncertainty.

  3. Computed optical interferometric tomography for high-speed volumetric cellular imaging.

    PubMed

    Liu, Yuan-Zhi; Shemonski, Nathan D; Adie, Steven G; Ahmad, Adeel; Bower, Andrew J; Carney, P Scott; Boppart, Stephen A

    2014-09-01

    Three-dimensional high-resolution imaging methods are important for cellular-level research. Optical coherence microscopy (OCM) is a low-coherence-based interferometry technology for cellular imaging with both high axial and lateral resolution. Using a high-numerical-aperture objective, OCM normally has a shallow depth of field and requires scanning the focus through the entire region of interest to perform volumetric imaging. With a higher-numerical-aperture objective, the image quality of OCM is affected by and more sensitive to aberrations. Interferometric synthetic aperture microscopy (ISAM) and computational adaptive optics (CAO) are computed imaging techniques that overcome the depth-of-field limitation and the effect of optical aberrations in optical coherence tomography (OCT), respectively. In this work we combine OCM with ISAM and CAO to achieve high-speed volumetric cellular imaging. Experimental imaging results of ex vivo human breast tissue, ex vivo mouse brain tissue, in vitro fibroblast cells in 3D scaffolds, and in vivo human skin demonstrate the significant potential of this technique for high-speed volumetric cellular imaging. PMID:25401012

  4. Computed optical interferometric tomography for high-speed volumetric cellular imaging

    PubMed Central

    Liu, Yuan-Zhi; Shemonski, Nathan D.; Adie, Steven G.; Ahmad, Adeel; Bower, Andrew J.; Carney, P. Scott; Boppart, Stephen A.

    2014-01-01

    Three-dimensional high-resolution imaging methods are important for cellular-level research. Optical coherence microscopy (OCM) is a low-coherence-based interferometry technology for cellular imaging with both high axial and lateral resolution. Using a high-numerical-aperture objective, OCM normally has a shallow depth of field and requires scanning the focus through the entire region of interest to perform volumetric imaging. With a higher-numerical-aperture objective, the image quality of OCM is affected by and more sensitive to aberrations. Interferometric synthetic aperture microscopy (ISAM) and computational adaptive optics (CAO) are computed imaging techniques that overcome the depth-of-field limitation and the effect of optical aberrations in optical coherence tomography (OCT), respectively. In this work we combine OCM with ISAM and CAO to achieve high-speed volumetric cellular imaging. Experimental imaging results of ex vivo human breast tissue, ex vivo mouse brain tissue, in vitro fibroblast cells in 3D scaffolds, and in vivo human skin demonstrate the significant potential of this technique for high-speed volumetric cellular imaging. PMID:25401012

  5. Resolution and noise trade-off analysis for volumetric CT

    SciTech Connect

    Li Baojun; Avinash, Gopal B.; Hsieh, Jiang

    2007-10-15

    Until recently, most studies addressing the trade-off between spatial resolution and quantum noise were performed in the context of single-slice CT. In this study, we extend the theoretical framework of previous works to volumetric CT and further extend it by taking into account the actual shapes of the preferred reconstruction kernels. In the experimental study, we also attempt to explore a three-dimensional approach for spatial resolution measurement, as opposed to the conventional two-dimensional approaches that were widely adopted in previously published studies. By scanning a finite-sized sphere phantom, the MTF was measured from the edge profile along the spherical surface. Cases of different resolutions (and noise levels) were generated by adjusting the reconstruction kernel. To reduce bias, the total photon fluxes were matched: 120 kVp, 200 mA, and 1 s per gantry rotation. All data sets were reconstructed using a modified FDK algorithm under the same condition: Scan field-of-view (SFOV)=10 cm, and slice thickness=0.625 mm. The theoretical analysis indicated that the variance of noise is proportional to >4th power of the spatial resolution. Our experimental results supported this conclusion by showing the relationship is 4.6th (helical) or 5th (axial) power.

  6. A low-resolution 3D holographic volumetric display

    NASA Astrophysics Data System (ADS)

    Khan, Javid; Underwood, Ian; Greenaway, Alan; Halonen, Mikko

    2010-05-01

    A simple low resolution volumetric display is presented, based on holographic volume-segments. The display system comprises a proprietary holographic screen, laser projector, associated optics plus a control unit. The holographic screen resembles a sheet of frosted glass about A4 in size (20x30cm). The holographic screen is rear-illuminated by the laser projector, which is in turn driven by the controller, to produce simple 3D images that appear outside the plane of the screen. A series of spatially multiplexed and interleaved interference patterns are pre-encoded across the surface of the holographic screen. Each illumination pattern is capable of reconstructing a single holographic volume-segment. Up to nine holograms are multiplexed on the holographic screen in a variety of configurations including a series of numeric and segmented digits. The demonstrator has good results under laboratory conditions with moving colour 3D images in front of or behind the holographic screen.

  7. In vivo volumetric imaging of chicken retina with ultrahigh-resolution spectral domain optical coherence tomography

    PubMed Central

    Moayed, Alireza Akhlagh; Hariri, Sepideh; Song, Eun Sun; Choh, Vivian; Bizheva, Kostadinka

    2011-01-01

    The chicken retina is an established animal model for myopia and light-associated growth studies. It has a unique morphology: it is afoveate and avascular; oxygen and nutrition to the inner retina is delivered by a vascular tissue (pecten) that protrudes into the vitreous. Here we present, to the best of our knowledge, the first in vivo, volumetric high-resolution images of the chicken retina. Images were acquired with an ultrahigh-resolution optical coherence tomography (UHROCT) system with 3.5 µm axial resolution in the retina, at the rate of 47,000 A-scans/s. Spatial variations in the thickness of the nerve fiber and ganglion cell layers were mapped by segmenting and measuring the layer thickness with a semi-automatic segmentation algorithm. Volumetric visualization of the morphology and morphometric analysis of the chicken retina could aid significantly studies with chicken retinal models of ophthalmic diseases. PMID:21559138

  8. 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.

  9. The spatial resolution of dual-tracer fluorescence thermometry in volumetrically illuminated channels

    NASA Astrophysics Data System (ADS)

    Kim, Myeongsub; Yoda, Minami

    2014-01-01

    This study estimates the spatial resolution and accuracy of dual-tracer fluorescence thermometry (DFT) for measuring water temperature fields in channels where the entire channel is illuminated as is typical in microfluidics. Temperature fields are measured in heated laminar Poiseuille flow through a 1 mm2 channel. The working fluid, an aqueous solution of the temperature-sensitive fluorophores fluorescein (Fl) and sulforhodamine B (SrB), is volumetrically illuminated over the entire channel cross-section at a wavelength of 514 nm, and the temperature of the solution is estimated from images of the longer-wavelength fluorescence from Fl and SrB. These temperature data are compared with numerical simulations of the same flow where the heat transferred to the water is estimated from independent measurements of wall surface temperature to determine the accuracy and the spatial resolution of the DFT results. The results suggest that temperature measurements in the volumetrically illuminated channel are significantly corrupted by the fluorescence emissions from beyond the focal plane. A model based on the point spread function for an aberration-free lens is employed to estimate the effect of the background "noise," i.e., the signal from beyond the object plane, on the accuracy of these DFT measurements. The results show that this background is about 30 times the signal from the focal plane. Further experiments where the channel is illuminated by a light sheet over about 40 % of the channel cross-section give estimates of the water temperature field that are on average within about 0.3 °C of the numerical predictions at an in-plane spatial resolution of 50 μm. The model is used to estimate the signal-to-background ratio for this case, as well as for a variety of commercially available microscope objectives.

  10. Computed tomography part 3: Volumetric, high-resolution x-ray analysis of fatigue crack closure

    NASA Astrophysics Data System (ADS)

    Stock, S. R.; Guvenilir, A.; Breunig, T. M.; Kinney, J. H.; Nichols, M. C.

    1995-01-01

    The study described illustrates how extremely high-resolution volumetric x-ray computed tomography can be applied to a materials problem. The work also gives an example of what choices must be made to tailor an experiment to the capabilities of a computed tomography system. Tomography is used to reconstruct the volume of material enclosing a fatigue crack in Al-Li2090. From the reconstructed volume, the separations of crack faces are quantified as a function of position within the sample, and, through use of a small load frame designed for use in computed tomography, the changing physical crack closure is measured as a function of applied load. In other words, the rate and amounts of physical crack closure are measured at different points of the unloading portion of a fatigue cycle.

  11. Utility of Early Post-operative High Resolution Volumetric MR Imaging after Transsphenoidal Pituitary Tumor Surgery

    PubMed Central

    Patel, Kunal S.; Kazam, Jacob; Tsiouris, Apostolos J.; Anand, Vijay K.; Schwartz, Theodore H.

    2014-01-01

    Objective Controversy exists over the utility of early post-operative magnetic resonance imaging (MRI) after transsphenoidal pituitary surgery for macroadenomas. We investigate whether valuable information can be derived from current higher resolution scans. Methods Volumetric MRI scans were obtained in the early (<10 days) and late (>30 days) post-operative periods in a series of patients undergoing transsphenoidal pituitary surgery. The volume of the residual tumor, resection cavity, and corresponding visual field tests were recorded at each time point. Statistical analyses of changes in tumor volume and cavity size were calculated using the late MRI as the gold standard. Results 40 patients met the inclusion criteria. Pre-operative tumor volume averaged 8.8 cm3. Early postoperative assessment of average residual tumor volume (1.18 cm3) was quite accurate and did not differ statistically from late post-operative volume (1.23 cm3, p=.64), indicating the utility of early scans to measure residual tumor. Early scans were 100% sensitive and 91% specific for predicting ≥ 98% resection (p<.001, Fisher’s exact test). The average percent decrease in cavity volume from pre-operative MRI (tumor volume) to early post-operative imaging was 45% with decreases in all but 3 patients. There was no correlation between the size of the early cavity and the visual outcome. Conclusions Early high resolution volumetric MRI is valuable in determining the presence or absence of residual tumor. Cavity volume almost always decreases after surgery and a lack of decrease should alert the surgeon to possible persistent compression of the optic apparatus that may warrant re-operation. PMID:25045791

  12. 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.

  13. 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. PMID:26712014

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

    PubMed Central

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

    2016-01-01

    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. PMID:26712014

  15. 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. PMID:26871636

  16. VolRoverN: Enhancing surface and volumetric reconstruction for realistic dynamical simulation of cellular and subcellular function

    PubMed Central

    Edwards, John; Daniel, Eric; Kinney, Justin; Bartol, Tom; Sejnowski, Terrence; Johnston, Daniel; Harris, Kristen; Bajaj, Chandrajit

    2014-01-01

    Establishing meaningful relationships between cellular structure and function requires accurate morphological reconstructions. In particular, there is an unmet need for high quality surface reconstructions to model subcellular and synaptic interactions among neurons at nanometer resolution. We address this need with VolRoverN, a software package that produces accurate, efficient, and automated 3D surface reconstructions from stacked 2D contour tracings. While many techniques and tools have been developed in the past for 3D visualization of cellular structure, the reconstructions from VolRoverN meet specific quality criteria that are important for dynamical simulations. These criteria include manifoldness, water-tightness, lack of self- and object-object-intersections, and geometric accuracy. These enhanced surface reconstructions are readily extensible to any cell type (including glia) and are used here on complex spiny dendrites and axons from mature rat hippocampal area CA1. Both spatially realistic surface reconstructions and reduced skeletonizations are produced and formatted by VolRoverN for easy input into analysis software packages for neurophysiological simulations at multiple spatial and temporal scales ranging from ion electro-diffusion to electrical cable models. PMID:24100964

  17. 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.

  18. Volumetric quantification of in vitro sonothrombolysis with microbubbles using high-resolution optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Kim, Jong S.; Leeman, Jonathan E.; Kagemann, Larry; Yu, Francois T. H.; Chen, Xucai; Pacella, John J.; Schuman, Joel S.; Villanueva, Flordeliza S.; Kim, Kang

    2012-07-01

    Several in vitro and in vivo studies have established accelerated thrombolysis using ultrasound (US) induced microbubble (MB) cavitation. However, the mechanisms underlying MB mediated sonothrombolysis are still not completely elucidated. We performed three-dimensional (3-D) volumetric optical coherence tomography (OCT) imaging before and after the application of contrast US to thrombus. The most dramatic reduction in clot volume was observed with US + MB + recombinant tissue plasminogen activator (rt-PA). Thrombus surface erosion in this group on the side of the thrombus exposed to MB and ultrasound was evident on the OCT images. This technique may assist in clarifying the mechanisms underlying sonothrombolysis, especially regarding the importance of US transducer orientation on lytic efficacy and the effects of MB cavitation on thrombus structure.

  19. 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

  20. 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. PMID:15645100

  1. 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

  2. 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

  3. 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

  4. Volumetric analysis of syringomyelia following hindbrain decompression for Chiari malformation Type I: syringomyelia resolution follows exponential kinetics

    PubMed Central

    Coumans, Jean-Valery; Walcott, Brian P.; Butler, William E.; Nahed, Brian V.; Kahle, Kristopher T.

    2013-01-01

    Object Resolution of syringomyelia is common following hindbrain decompression for Chiari malformation, yet little is known about the kinetics governing this process. The authors sought to establish the volumetric rate of syringomyelia resolution. Methods A retrospective cohort of patients undergoing hindbrain decompression for a Chiari malformation Type I with preoperative cervical or thoracic syringomyelia was identified. Patients were included in the study if they had at least 3 neuroimaging studies that detailed the entirety of their preoperative syringomyelia over a minimum of 6 months postoperatively. The authors reconstructed the MR images in 3 dimensions and calculated the volume of the syringomyelia. They plotted the syringomyelia volume over time and constructed regression models using the method of least squares. The Akaike information criterion and Bayesian information criterion were used to calculate the relative goodness of fit. The coefficients of determination R2 (unadjusted and adjusted) were calculated to describe the proportion of variability in each individual data set accounted for by the statistical model. Results Two patients were identified as meeting inclusion criteria. Plots of the least-squares best fit were identified as 4.01459e−0.0180804x and 13.2556e−0.00615859x. Decay of the syringomyelia followed an exponential model in both patients (R2 = 0.989582 and 0.948864). Conclusions Three-dimensional analysis of syringomyelia resolution over time enables the kinetics to be estimated. This technique is yet to be validated in a large cohort. Because syringomyelia is the final common pathway for a number of different pathological processes, it is possible that this exponential only applies to syringomyelia related to treatment of Chiari malformation Type I. PMID:21882909

  5. High-resolution imaging of cellular processes in Caenorhabditis elegans.

    PubMed

    Maddox, Amy S; Maddox, Paul S

    2012-01-01

    Differential interference contrast (DIC) imaging of Caenorhabditis elegans embryogenesis led to a Nobel Prize in Physiology or Medicine (Sulston et al., 1983) as did the first use of green fluorescent protein (GFP) in a transgenic C. elegans (Chalfie et al., 1994). Given that C. elegans is free living, does not require exceptional environmental control, and is optically clear, live imaging is a powerful tool in for this model system. Combining genetics with high-resolution imaging has continued to make important contributions to many fields. In this chapter, we discuss how certain aspects of high-resolution microscopy are implemented. This is not an exhaustive review of microscopy; it is meant to be a helpful guide and point of reference for some basic concepts in imaging. While these concepts are largely true for all biological imaging, they are chosen as particularly important for C. elegans. PMID:22226519

  6. Towards a High Resolution Cellular Model for Coastal Simulation (CEMCOS)

    NASA Astrophysics Data System (ADS)

    Dearing, J.; Plater, A. J.; Richmond, N. C.

    2004-12-01

    The aim of this research is to develop a cellular model for coastal simulation in response to changing climate and sea-level, as a contribution to the UK Tyndall Centre's Research Theme 4: Sustaining the Coastal Zone. The modelling approach uses simple cell-based rules of sediment erosion, transport and deposition operating between adjacent cells. This enables the model to include the full range of processes and properties of the coastal environment, including nonlinear behaviour, using only local interactions at discrete time intervals. Tide propagation and wave action drive sediment transport, which is further conditioned by erosion thresholds related to grain size and vegetation growth. Here, we report an overview of this one-year project and details on model design and validation. This includes tide and wave parameterisation, resulting in sediment transport over a 3-D grid of cells representing estuary morphology and bathymetry. The model (CEMCOS) is being designed to be fully generic and exportable to different coastal areas, with initial testing and validation being conducted using published bathymetric and cartographic data over the last c.150 years for the Blackwater Estuary in eastern England.

  7. 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

  8. Influence of fat-water separation and spatial resolution on automated volumetric MRI measurements of fibroglandular breast tissue.

    PubMed

    Wengert, Georg J; Pinker-Domenig, Katja; Helbich, Thomas H; Vogl, Wolf-Dieter; Clauser, Paola; Bickel, Hubert; Marino, Maria-Adele; Magometschnigg, Heinrich F; Baltzer, Pascal A

    2016-06-01

    The aim of this study was to investigate the influence of fat-water separation and spatial resolution in MRI on the results of automated quantitative measurements of fibroglandular breast tissue (FGT). Ten healthy volunteers (age range, 28-71 years; mean, 39.9 years) were included in this Institutional Review Board-approved prospective study. All measurements were performed on a 1.5-T scanner (Siemens, AvantoFit) using an 18-channel breast coil. The protocols included isotropic (Di) [TR/TE1 /TE2  = 6.00 ms/2.45 ms/2.67 ms; flip angle, 6.0°; 256 slices; matrix, 360 × 360; 1 mm isotropic; field of view, 360°; acquisition time (TA) = 3 min 38 s] and anisotropic (Da) (TR/TE1 /TE2  = 10.00 ms/2.39 ms/4.77 ms; flip angle, 24.9°; 80 slices; matrix 360 × 360; voxel size, 0.7 × 0.7 × 2.0 mm(3) ; field of view, 360°; TA = 1 min 25 s) T1 three-dimensional (3D) fast low-angle shot (FLASH) Dixon sequences, and a T1 3D FLASH sequence with the same resolution (T1 ) without (TR/TE = 11.00 ms/4.76 ms; flip angle, 25.0°; 80 slices; matrix, 360 × 360; voxel size, 0.7 × 0.7 × 2.0 mm(3) ; field of view, 360°; TA = 50 s) and with (TR/TE = 29.00 ms/4.76 ms; flip angle, 25.0°; 80 slices; matrix, 360 × 360; voxel size, 0.7 × 0.7 × 2.0 mm(3) ; field of view, 360°; TA = 2 min 35 s) fat saturation. Repeating volunteer measurements after 20 min and repositioning were used to assess reproducibility. An automated and quantitative volumetric breast density measurement system was used for FGT calculation. FGT with Di, Da and T1 measured 4.6-63.0% (mean, 30.6%), 3.2-65.3% (mean, 32.5%) and 1.7-66.5% (mean, 33.7%), respectively. The highest correlation between different MRI sequences was found with the Di and Da sequences (R(2)  = 0.976). Coefficients of variation (CVs) for FGT calculation were higher in T1 (CV = 21.5%) compared with Dixon (Di, CV = 5

  9. 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.

  10. 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.

  11. Volumetric feature extraction and visualization of tomographic molecular imaging.

    PubMed

    Bajaj, Chandrajit; Yu, Zeyun; Auer, Manfred

    2003-01-01

    Electron tomography is useful for studying large macromolecular complex within their cellular context. The associate problems include crowding and complexity. Data exploration and 3D visualization of complexes require rendering of tomograms as well as extraction of all features of interest. We present algorithms for fully automatic boundary segmentation and skeletonization, and demonstrate their applications in feature extraction and visualization of cell and molecular tomographic imaging. We also introduce an interactive volumetric exploration and visualization tool (Volume Rover), which encapsulates implementations of the above volumetric image processing algorithms, and additionally uses efficient multi-resolution interactive geometry and volume rendering techniques for interactive visualization. PMID:14643216

  12. Automated detection and quantification of single RNAs at cellular resolution in zebrafish embryos.

    PubMed

    Stapel, L Carine; Lombardot, Benoit; Broaddus, Coleman; Kainmueller, Dagmar; Jug, Florian; Myers, Eugene W; Vastenhouw, Nadine L

    2016-02-01

    Analysis of differential gene expression is crucial for the study of cell fate and behavior during embryonic development. However, automated methods for the sensitive detection and quantification of RNAs at cellular resolution in embryos are lacking. With the advent of single-molecule fluorescence in situ hybridization (smFISH), gene expression can be analyzed at single-molecule resolution. However, the limited availability of protocols for smFISH in embryos and the lack of efficient image analysis pipelines have hampered quantification at the (sub)cellular level in complex samples such as tissues and embryos. Here, we present a protocol for smFISH on zebrafish embryo sections in combination with an image analysis pipeline for automated transcript detection and cell segmentation. We use this strategy to quantify gene expression differences between different cell types and identify differences in subcellular transcript localization between genes. The combination of our smFISH protocol and custom-made, freely available, analysis pipeline will enable researchers to fully exploit the benefits of quantitative transcript analysis at cellular and subcellular resolution in tissues and embryos. PMID:26700682

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

    PubMed

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

    2015-12-01

    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

  14. 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

  15. 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.

  16. 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

  17. 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

  18. 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

    2015-01-01

    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

  19. Automated analysis of embryonic gene expression with cellular resolution in C. elegans

    PubMed Central

    Murray, John Isaac; Bao, Zhirong; Boyle, Thomas J.; Boeck, Max E.; Mericle, Barbara L.; Nicholas, Thomas J.; Zhao, Zhongying; Sandel, Matthew J.; Waterston, Robert H.

    2008-01-01

    We describe a system that permits the automated analysis of reporter gene expression in Caenorhabditis elegans with cellular resolution continuously during embryogenesis and demonstrate its utility by defining the expression patterns of reporters for several embryonically expressed transcription factors. The invariant cell lineage permits the automated alignment of multiple expression profiles, allowing the direct comparison of the expression of different genes' reporters. We have also used the system to monitor perturbations to normal development involving changes both in cell division timing and in cell fate. Systematic application could reveal the gene activity of each cell throughout development. PMID:18587405

  20. 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

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

    PubMed Central

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

    2016-01-01

    We describe an all-optical strategy for simultaneously manipulating and recording the activity of multiple neurons with cellular resolution in vivo. Concurrent two-photon optogenetic activation and calcium imaging is enabled 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 optogenetic activation, while simultaneous fast calcium imaging provides high-resolution network-wide readout of the manipulation with negligible optical crosstalk. 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 mammalian brain in vivo. PMID:25532138

  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. Optical-Resolution Photoacoustic Microscopy: Auscultation of Biological Systems at the Cellular Level

    PubMed Central

    Hu, Song; Wang, Lihong V.

    2013-01-01

    Photoacoustic microscopy (PAM) offers unprecedented sensitivity to optical absorption and opens a new window to study biological systems at multiple length- and timescales. In particular, optical-resolution PAM (OR-PAM) has pushed the technical envelope to submicron length scales and millisecond timescales. Here, we review the state of the art of OR-PAM in biophysical research. With properly chosen optical wavelengths, OR-PAM can spectrally differentiate a variety of endogenous and exogenous chromophores, unveiling the anatomical, functional, metabolic, and molecular information of biological systems. Newly uncovered contrast mechanisms of linear dichroism and Förster resonance energy transfer further distinguish OR-PAM. Integrating multiple contrasts and advanced scanning mechanisms has capacitated OR-PAM to comprehensively interrogate biological systems at the cellular level in real time. Two future directions are discussed, where OR-PAM holds the potential to translate basic biophysical research into clinical healthcare. PMID:23972836

  4. Magnetic spin imaging under ambient conditions with sub-cellular resolution

    NASA Astrophysics Data System (ADS)

    Steinert, S.; Ziem, F.; Hall, L. T.; Zappe, A.; Schweikert, M.; Götz, N.; Aird, A.; Balasubramanian, G.; Hollenberg, L.; Wrachtrup, J.

    2013-03-01

    The detection of small numbers of magnetic spins is a significant challenge in the life, physical and chemical sciences, especially when room temperature operation is required. Here we show that a proximal nitrogen-vacancy spin ensemble serves as a high precision sensing and imaging array. Monitoring its longitudinal relaxation enables sensing of freely diffusing, unperturbed magnetic ions and molecules in a microfluidic device without applying external magnetic fields. Multiplexed charge-coupled device acquisition and an optimized detection scheme permits direct spin noise imaging of magnetically labelled cellular structures under ambient conditions. Within 20 s we achieve spatial resolutions below 500 nm and experimental sensitivities down to 1,000 statistically polarized spins, of which only 32 ions contribute to a net magnetization. The results mark a major step towards versatile sub-cellular magnetic imaging and real-time spin sensing under physiological conditions providing a minimally invasive tool to monitor ion channels or haemoglobin trafficking inside live cells.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. Three-dimensional morphology and gene expression in the Drosophila blastoderm at cellular resolution II: dynamics

    PubMed Central

    Keränen, Soile VE; Fowlkes, Charless C; Luengo Hendriks, Cris L; Sudar, Damir; Knowles, David W; Malik, Jitendra; Biggin, Mark D

    2006-01-01

    Background To accurately describe gene expression and computationally model animal transcriptional networks, it is essential to determine the changing locations of cells in developing embryos. Results Using automated image analysis methods, we provide the first quantitative description of temporal changes in morphology and gene expression at cellular resolution in whole embryos, using the Drosophila blastoderm as a model. Analyses based on both fixed and live embryos reveal complex, previously undetected three-dimensional changes in nuclear density patterns caused by nuclear movements prior to gastrulation. Gene expression patterns move, in part, with these changes in morphology, but additional spatial shifts in expression patterns are also seen, supporting a previously proposed model of pattern dynamics based on the induction and inhibition of gene expression. We show that mutations that disrupt either the anterior/posterior (a/p) or the dorsal/ventral (d/v) transcriptional cascades alter morphology and gene expression along both the a/p and d/v axes in a way suggesting that these two patterning systems interact via both transcriptional and morphological mechanisms. Conclusion Our work establishes a new strategy for measuring temporal changes in the locations of cells and gene expression patterns that uses fixed cell material and computational modeling. It also provides a coordinate framework for the blastoderm embryo that will allow increasingly accurate spatio-temporal modeling of both the transcriptional control network and morphogenesis. PMID:17184547

  13. Automated Identification of Closed Mesoscale Cellular Convection and Impact of Resolution on Related Mesoscale Dynamics

    NASA Astrophysics Data System (ADS)

    Martini, M.; Gustafson, W. I.; Yang, Q.; Xiao, H.

    2013-12-01

    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. Cloud resolving models begin to resolve some, but not all, of these processes with less of the mesoscale dynamics resolved as one progresses from <1 km to 10 km grid spacing. While limited domain cloud resolving models can use high resolution to simulate MCC, global cloud resolving models must resort to using grid spacings closer to 5 to 10 km. This effectively truncates the scales through which the dynamics can act and impacts the MCC characteristics, potentially altering the climate impact of these clouds in climate models. To understand the impact of this truncation, 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 1-, 3- and 9-km grid spacing indicates resolution dependent behavior. The simulations with finer grid spacing have lower liquid water paths and cloud fractions, while cloud tops are higher. When compared to observed liquid water paths from GOES and MODIS, the 3-km simulation has better agreement over the coastal regions while the 9-km simulation better agrees over remote regions. The observed diurnal cycle is reasonably well simulated. To isolate organized MCC characteristics we developed 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 has the advantage of ensuring that the detected cloud fields are dynamically consistent for closed MCC and helps minimize false detections from secondary circulations. We demonstrate that the 3-km simulation is able to reproduce the scaling between

  14. Snapshot Hyperspectral Volumetric Microscopy.

    PubMed

    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

  15. 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.

  16. 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

  17. 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

  18. High-resolution gene expression analysis of the developing mouse kidney defines novel cellular compartments within the nephron progenitor population.

    PubMed

    Mugford, Joshua W; Yu, Jing; Kobayashi, Akio; McMahon, Andrew P

    2009-09-15

    The functional unit of the kidney is the nephron. During its organogenesis, the mammalian metanephric kidney generates thousands of nephrons over a protracted period of fetal life. All nephrons are derived from a population of self-renewing multi-potent progenitor cells, termed the cap mesenchyme. However, our understanding of the molecular and cellular mechanisms underlying nephron development is at an early stage. In order to identify factors involved in nephrogenesis, we performed a high-resolution, spatial profiling of a number of transcriptional regulators expressed within the cap mesenchyme and early developing nephron. Our results demonstrate novel, stereotypic, spatially defined cellular sub-domains within the cap mesenchyme, which may, in part, reflect induction of nephron precursors. These results suggest a hitherto unappreciated complexity of cell states that accompany the assembly of the metanephric kidney, likely reflecting diverse regulatory actions such as the maintenance and induction of nephron progenitors. PMID:19591821

  19. High-resolution gene expression analysis of the developing mouse kidney defines novel cellular compartments within the nephron progenitor population

    PubMed Central

    Mugford, Joshua W.; Yu, Jing; Kobayashi, Akio; McMahon, Andrew P.

    2009-01-01

    The functional unit of the kidney is the nephron. During its organogenesis, the mammalian metanephric kidney generates thousands of nephrons over a protracted period of fetal life. All nephrons are derived from a population of self-renewing multi-potent progenitor cells, termed the cap mesenchyme. However, our understanding of the molecular and cellular mechanisms underlying nephron development is at an early stage. In order to identify factors involved in nephrogenesis, we performed a high-resolution, spatial profiling of a number of transcriptional regulators expressed within the cap mesenchyme and early developing nephron. Our results demonstrate novel, stereotypic, spatially defined cellular sub-domains within the cap mesenchyme, which may, in part, reflect induction of nephron precursors. These results suggest a hitherto unappreciated complexity of cell states that accompany the assembly of the metanephric kidney, likely reflecting diverse regulatory actions such as the maintenance and induction of nephron progenitors. PMID:19591821

  20. Efficient threshold for volumetric segmentation

    NASA Astrophysics Data System (ADS)

    Burdescu, Dumitru D.; Brezovan, Marius; Stanescu, Liana; Stoica Spahiu, Cosmin; Ebanca, Daniel

    2015-07-01

    Image segmentation plays a crucial role in effective understanding of digital images. However, the research on the existence of general purpose segmentation algorithm that suits for variety of applications is still very much active. Among the many approaches in performing image segmentation, graph based approach is gaining popularity primarily due to its ability in reflecting global image properties. Volumetric image segmentation can simply result an image partition composed by relevant regions, but the most fundamental challenge in segmentation algorithm is to precisely define the volumetric extent of some object, which may be represented by the union of multiple regions. The aim in this paper is to present a new method to detect visual objects from color volumetric images and efficient threshold. We present a unified framework for volumetric image segmentation and contour extraction that uses a virtual tree-hexagonal structure defined on the set of the image voxels. The advantage of using a virtual tree-hexagonal network superposed over the initial image voxels is that it reduces the execution time and the memory space used, without losing the initial resolution of the image.

  1. Imaging cellular structures in super-resolution with SIM, STED and Localisation Microscopy: A practical comparison

    PubMed Central

    Wegel, Eva; Göhler, Antonia; Lagerholm, B. Christoffer; Wainman, Alan; Uphoff, Stephan; Kaufmann, Rainer; Dobbie, Ian M.

    2016-01-01

    Many biological questions require fluorescence microscopy with a resolution beyond the diffraction limit of light. Super-resolution methods such as Structured Illumination Microscopy (SIM), STimulated Emission Depletion (STED) microscopy and Single Molecule Localisation Microscopy (SMLM) enable an increase in image resolution beyond the classical diffraction-limit. Here, we compare the individual strengths and weaknesses of each technique by imaging a variety of different subcellular structures in fixed cells. We chose examples ranging from well separated vesicles to densely packed three dimensional filaments. We used quantitative and correlative analyses to assess the performance of SIM, STED and SMLM with the aim of establishing a rough guideline regarding the suitability for typical applications and to highlight pitfalls associated with the different techniques. PMID:27264341

  2. 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.

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

    PubMed

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

    2015-01-01

    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. PMID:25762114

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

    PubMed Central

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

    2015-01-01

    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. PMID:25762114

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

    PubMed

    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. PMID:27525487

  6. The stress response resolution assay. I. Quantitative assessment of environmental agent/condition effects on cellular stress resolution outcomes in epithelium.

    PubMed

    Walker, Dale M; Patrick O'Neill, J; Tyson, Frederick L; Walker, Vernon E

    2013-05-01

    The events or factors that lead from normal cell function to conditions and diseases such as aging or cancer reflect complex interactions between cells and their environment. Cellular stress responses, a group of processes involved in homeostasis and adaptation to environmental change, contribute to cell survival under stress and can be resolved with damage avoidance or damage tolerance outcomes. To investigate the impact of environmental agents/conditions upon cellular stress response outcomes in epithelium, a novel quantitative assay, the "stress response resolution" (SRR) assay, was developed. The SRR assay consists of pretreatment with a test agent or vehicle followed later by a calibrated stress conditions exposure step (here, using 6-thioguanine). Pilot studies conducted with a spontaneously-immortalized murine mammary epithelial cell line pretreated with vehicle or 20 µg N-ethyl-N-nitrososurea/ml medium for 1 hr, or two hTERT-immortalized human bronchial epithelial cell lines pretreated with vehicle or 100 µM zidovudine/lamivudine for 12 days, found minimal alterations in cell morphology, survival, or cell function through 2 weeks post-exposure. However, when these pretreatments were followed 2 weeks later by exposure to calibrated stress conditions of limited duration (for 4 days), significant alterations in stress resolution were observed in pretreated cells compared with vehicle-treated control cells, with decreased damage avoidance survival outcomes in all cell lines and increased damage tolerance outcomes in two of three cell lines. These pilot study results suggest that sub-cytotoxic pretreatments with chemical mutagens have long-term adverse impact upon the ability of cells to resolve subsequent exposure to environmental stressors. PMID:23554083

  7. 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

  8. Exploring Volumetrically Indexed Cups

    ERIC Educational Resources Information Center

    Jones, Dustin L.

    2011-01-01

    This article was inspired by a set of 12 cylindrical cups, which are volumetrically indexed; that is to say, the volume of cup "n" is equal to "n" times the volume of cup 1. Various sets of volumetrically indexed cylindrical cups are explored. I demonstrate how this children's toy is ripe for mathematical investigation, with connections to…

  9. 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

  10. 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. PMID:25775601

  11. Cellular resolution maps of X-chromosome inactivation: implications for neural development, function, and disease

    PubMed Central

    Wu, Hao; Luo, Junjie; Yu, Huimin; Rattner, Amir; Mo, Alisa; Wang, Yanshu; Smallwood, Philip M.; Erlanger, Bracha; Wheelan, Sarah J.; Nathans, Jeremy

    2014-01-01

    Female eutherian mammals use X-chromosome inactivation (XCI) to epigenetically regulate gene expression from ~4% of genes. To quantitatively map the topography of XCI for defined cell types at single cell resolution, we have generated female mice that carry X-linked, Cre-activated, and nuclear-localized fluorescent reporters – GFP on one X-chromosome and tdTomato on the other. Using these reporters in combination with different Cre drivers we have defined the topographies of XCI mosaicism for multiple CNS cell types and of retinal vascular dysfunction in a model of Norrie Disease. Depending on cell type, fluctuations in the XCI mosaic are observed over a wide range of spatial scales, from neighboring cells to left vs. right sides of the body. These data imply a major role for XCI in generating female-specific, genetically directed, stochastic diversity in eutherian mammals on spatial scales that would be predicted to affect CNS function within and between individuals. PMID:24411735

  12. Cellular resolution maps of X chromosome inactivation: implications for neural development, function, and disease.

    PubMed

    Wu, Hao; Luo, Junjie; Yu, Huimin; Rattner, Amir; Mo, Alisa; Wang, Yanshu; Smallwood, Philip M; Erlanger, Bracha; Wheelan, Sarah J; Nathans, Jeremy

    2014-01-01

    Female eutherian mammals use X chromosome inactivation (XCI) to epigenetically regulate gene expression from ∼4% of the genome. To quantitatively map the topography of XCI for defined cell types at single cell resolution, we have generated female mice that carry X-linked, Cre-activated, and nuclear-localized fluorescent reporters--GFP on one X chromosome and tdTomato on the other. Using these reporters in combination with different Cre drivers, we have defined the topographies of XCI mosaicism for multiple CNS cell types and of retinal vascular dysfunction in a model of Norrie disease. Depending on cell type, fluctuations in the XCI mosaic are observed over a wide range of spatial scales, from neighboring cells to left versus right sides of the body. These data imply a major role for XCI in generating female-specific, genetically directed, stochastic diversity in eutherian mammals on spatial scales that would be predicted to affect CNS function within and between individuals. PMID:24411735

  13. 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.

  14. High-resolution FTIR imaging of colon tissues for elucidation of individual cellular and histopathological features.

    PubMed

    Nallala, Jayakrupakar; Lloyd, Gavin Rhys; Shepherd, Neil; Stone, Nick

    2016-01-21

    Novel technologies that could complement current histopathology based cancer diagnostic methods are under examination. In this endeavour mid-infrared spectroscopic imaging is a promising candidate that can provide valuable bio-molecular information from unstained cells and tissues in a rapid and a non-destructive manner. With this imaging technique, the biochemical information obtained from smaller areas of the tissues can be of clinical significance and hence the measured pixel size. Until recently it was difficult to obtain spectral data from pixels below around 5 microns square. High NA objectives have been utilised to reduce the ideal diffraction limit, enabling for the first time elucidation of subcellular features. In this context, the ability of high-resolution imaging, obtained using novel high-magnification optics retro-fitted onto a bench top FTIR imaging system, to characterise histopathological features in colonic tissues has been tested. Formalin fixed paraffin embedded colon tissues from three different pathologies were imaged directly using the conventional and the high-magnification imaging set-ups. To circumvent chemical de-paraffinization protocols, an extended multiplicative signal correction (EMSC) based electronic de-paraffinization was carried out on all the infrared images. Multivariate analysis of the high-magnification infrared imaging data showed a detailed information of the histological features of the colon tissue in comparison to conventional imaging. Furthermore, high-magnification imaging has enabled a label-free characterization of the mucin rich goblet cell features in an unprecedented manner. The current study demonstrates the applicability of high-magnification FTIR imaging to characterise complex tissues on a smaller scale that could be of clinical significance. PMID:26549223

  15. Exploring volumetrically indexed cups

    NASA Astrophysics Data System (ADS)

    Jones, Dustin L.

    2011-03-01

    This article was inspired by a set of 12 cylindrical cups, which are volumetrically indexed; that is to say, the volume of cup n is equal to n times the volume of cup 1. Various sets of volumetrically indexed cylindrical cups are explored. I demonstrate how this children's toy is ripe for mathematical investigation, with connections to geometry, algebra and differential calculus. Students with an understanding of these topics should be able to complete the analysis and related exercises contained herein.

  16. AFM-based Mapping of the Elastic Properties of Cell Walls: at Tissue, Cellular, and Subcellular Resolutions

    PubMed Central

    Peaucelle, Alexis

    2014-01-01

    We describe a recently developed method to measure mechanical properties of the surfaces of plant tissues using atomic force microscopy (AFM) micro/nano-indentations, for a JPK AFM. Specifically, in this protocol we measure the apparent Young’s modulus of cell walls at subcellular resolutions across regions of up to 100 µm x 100 µm in floral meristems, hypocotyls, and roots. This requires careful preparation of the sample, the correct selection of micro-indenters and indentation depths. To account for cell wall properties only, measurements are performed in highly concentrated solutions of mannitol in order to plasmolyze the cells and thus remove the contribution of cell turgor pressure. In contrast to other extant techniques, by using different indenters and indentation depths, this method allows simultaneous multiscale measurements, i.e. at subcellular resolutions and across hundreds of cells comprising a tissue. This means that it is now possible to spatially-temporally characterize the changes that take place in the mechanical properties of cell walls during development, enabling these changes to be correlated with growth and differentiation. This represents a key step to understand how coordinated microscopic cellular changes bring about macroscopic morphogenetic events. However, several limitations remain: the method can only be used on fairly small samples (around 100 µm in diameter) and only on external tissues; the method is sensitive to tissue topography; it measures only certain aspects of the tissue’s complex mechanical properties. The technique is being developed rapidly and it is likely that most of these limitations will be resolved in the near future. PMID:25080133

  17. A medaka model of cancer allowing direct observation of transplanted tumor cells in vivo at a cellular-level resolution.

    PubMed

    Hasegawa, Sumitaka; Maruyama, Kouichi; Takenaka, Hikaru; Furukawa, Takako; Saga, Tsuneo

    2009-08-18

    The recent success with small fish as an animal model of cancer with the aid of fluorescence technique has attracted cancer modelers' attention because it would be possible to directly visualize tumor cells in vivo in real time. Here, we report a medaka model capable of allowing the observation of various cell behaviors of transplanted tumor cells, such as cell proliferation and metastasis, which were visualized easily in vivo. We established medaka melanoma (MM) cells stably expressing GFP and transplanted them into nonirradiated and irradiated medaka. The tumor cells were grown at the injection sites in medaka, and the spatiotemporal changes were visualized under a fluorescence stereoscopic microscope at a cellular-level resolution, and even at a single-cell level. Tumor dormancy and metastasis were also observed. Interestingly, in irradiated medaka, accelerated tumor growth and metastasis of the transplanted tumor cells were directly visualized. Our medaka model provides an opportunity to visualize in vivo tumor cells "as seen in a culture dish" and would be useful for in vivo tumor cell biology. PMID:19666513

  18. A medaka model of cancer allowing direct observation of transplanted tumor cells in vivo at a cellular-level resolution

    PubMed Central

    Hasegawa, Sumitaka; Maruyama, Kouichi; Takenaka, Hikaru; Furukawa, Takako; Saga, Tsuneo

    2009-01-01

    The recent success with small fish as an animal model of cancer with the aid of fluorescence technique has attracted cancer modelers' attention because it would be possible to directly visualize tumor cells in vivo in real time. Here, we report a medaka model capable of allowing the observation of various cell behaviors of transplanted tumor cells, such as cell proliferation and metastasis, which were visualized easily in vivo. We established medaka melanoma (MM) cells stably expressing GFP and transplanted them into nonirradiated and irradiated medaka. The tumor cells were grown at the injection sites in medaka, and the spatiotemporal changes were visualized under a fluorescence stereoscopic microscope at a cellular-level resolution, and even at a single-cell level. Tumor dormancy and metastasis were also observed. Interestingly, in irradiated medaka, accelerated tumor growth and metastasis of the transplanted tumor cells were directly visualized. Our medaka model provides an opportunity to visualize in vivo tumor cells “as seen in a culture dish” and would be useful for in vivo tumor cell biology. PMID:19666513

  19. The iRoCS Toolbox--3D analysis of the plant root apical meristem at cellular resolution.

    PubMed

    Schmidt, Thorsten; Pasternak, Taras; Liu, Kun; Blein, Thomas; Aubry-Hivet, Dorothée; Dovzhenko, Alexander; Duerr, Jasmin; Teale, William; Ditengou, Franck A; Burkhardt, Hans; Ronneberger, Olaf; Palme, Klaus

    2014-03-01

    To achieve a detailed understanding of processes in biological systems, cellular features must be quantified in the three-dimensional (3D) context of cells and organs. We described use of the intrinsic root coordinate system (iRoCS) as a reference model for the root apical meristem of plants. iRoCS enables direct and quantitative comparison between the root tips of plant populations at single-cell resolution. The iRoCS Toolbox automatically fits standardized coordinates to raw 3D image data. It detects nuclei or segments cells, automatically fits the coordinate system, and groups the nuclei/cells into the root's tissue layers. The division status of each nucleus may also be determined. The only manual step required is to mark the quiescent centre. All intermediate outputs may be refined if necessary. The ability to learn the visual appearance of nuclei by example allows the iRoCS Toolbox to be easily adapted to various phenotypes. The iRoCS Toolbox is provided as an open-source software package, licensed under the GNU General Public License, to make it accessible to a broad community. To demonstrate the power of the technique, we measured subtle changes in cell division patterns caused by modified auxin flux within the Arabidopsis thaliana root apical meristem. PMID:24417645

  20. Volumetric retinal imaging with ultrahigh-resolution spectral-domain optical coherence tomography and adaptive optics using two broadband light sources◊

    PubMed Central

    Cense, Barry; Koperda, Eric; Brown, Jeffrey M.; Kocaoglu, Omer P.; Gao, Weihua; Jonnal, Ravi S.; Miller, Donald T.

    2009-01-01

    Ultrabroadband sources, such as multiplexed superluminescent diodes (SLDs) and femtosecond lasers, have been successfully employed in adaptive optics optical coherence tomography (AO-OCT) systems for ultrahigh resolution retinal imaging. The large cost differential of these sources, however, motivates the need for a performance comparison. Here, we compare the performance of a Femtolasers Integral Ti:Sapphire laser and a Superlum BroadLighter T840, using the same AO-OCT system and the same subject. In addition, we investigate the capability of our instrument equipped with the Integral to capture volume images of the fovea and adjacent regions on a second subject using the AO to control focus in the retina and custom and freeware image registration software to reduce eye motion artifacts. Monochromatic ocular aberrations were corrected with a woofer-tweeter AO system. Coherence lengths of the Integral and BroadLighter were measured in vivo at 3.2 μm and 3.3 μm, respectively. The difference in dynamic range was 5 dB, close to the expected variability of the experiment. Individual cone photoreceptors, retinal capillaries and nerve fiber bundles were distinguished in all three dimensions with both sources. The acquired retinal volumes are provided for viewing in OSA ISP, allowing the reader to data mine at the microscope level. PMID:19259249

  1. 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.

  2. 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.

  3. 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.

  4. Volumetric Muscle Loss.

    PubMed

    Pollot, Beth E; Corona, Benjamin T

    2016-01-01

    Volumetric muscle loss (VML) injury is prevalent in severe extremity trauma and is an emerging focus area among orthopedic and regenerative medicine fields. VML injuries are the result of an abrupt, frank loss of tissue and therefore of different etiology from other standard rodent injury models to include eccentric contraction, ischemia reperfusion, crush, and freeze injury. The current focus of many VML-related research efforts is to regenerate the lost muscle tissue and thereby improve muscle strength. Herein, we describe a VML model in the anterior compartment of the hindlimb that is permissible to repeated neuromuscular strength assessments and is validated in mouse, rat, and pig. PMID:27492162

  5. 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.

  6. 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.

  7. High resolution light-sheet based high-throughput imaging cytometry system enables visualization of intra-cellular organelles

    NASA Astrophysics Data System (ADS)

    Regmi, Raju; Mohan, Kavya; Mondal, Partha Pratim

    2014-09-01

    Visualization of intracellular organelles is achieved using a newly developed high throughput imaging cytometry system. This system interrogates the microfluidic channel using a sheet of light rather than the existing point-based scanning techniques. The advantages of the developed system are many, including, single-shot scanning of specimens flowing through the microfluidic channel at flow rate ranging from micro- to nano- lit./min. Moreover, this opens-up in-vivo imaging of sub-cellular structures and simultaneous cell counting in an imaging cytometry system. We recorded a maximum count of 2400 cells/min at a flow-rate of 700 nl/min, and simultaneous visualization of fluorescently-labeled mitochondrial network in HeLa cells during flow. The developed imaging cytometry system may find immediate application in biotechnology, fluorescence microscopy and nano-medicine.

  8. 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

  9. Ligand Binding Induces Conformational Changes in Human Cellular Retinol-binding Protein 1 (CRBP1) Revealed by Atomic Resolution Crystal Structures.

    PubMed

    Silvaroli, Josie A; Arne, Jason M; Chelstowska, Sylwia; Kiser, Philip D; Banerjee, Surajit; Golczak, Marcin

    2016-04-15

    Important in regulating the uptake, storage, and metabolism of retinoids, cellular retinol-binding protein 1 (CRBP1) is essential for trafficking vitamin A through the cytoplasm. However, the molecular details of ligand uptake and targeted release by CRBP1 remain unclear. Here we report the first structure of CRBP1 in a ligand-free form as well as ultra-high resolution structures of this protein bound to either all-trans-retinol or retinylamine, the latter a therapeutic retinoid that prevents light-induced retinal degeneration. Superpositioning of human apo- and holo-CRBP1 revealed major differences within segments surrounding the entrance to the retinoid-binding site. These included α-helix II and hairpin turns between β-strands βC-βD and βE-βF as well as several side chains, such as Phe-57, Tyr-60, and Ile-77, that change their orientations to accommodate the ligand. Additionally, we mapped hydrogen bond networks inside the retinoid-binding cavity and demonstrated their significance for the ligand affinity. Analyses of the crystallographic B-factors indicated several regions with higher backbone mobility in the apoprotein that became more rigid upon retinoid binding. This conformational flexibility of human apo-CRBP1 facilitates interaction with the ligands, whereas the more rigid holoprotein structure protects the labile retinoid moiety during vitamin A transport. These findings suggest a mechanism of induced fit upon ligand binding by mammalian cellular retinol-binding proteins. PMID:26900151

  10. 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

  11. Imaging of cellular spread on a three-dimensional scaffold by means of a novel cell-labeling technique for high-resolution computed tomography.

    PubMed

    Thimm, Benjamin W; Hofmann, Sandra; Schneider, Philipp; Carretta, Roberto; Müller, Ralph

    2012-03-01

    Computed tomography (CT) represents a truly three-dimensional (3D) imaging technique that can provide high-resolution images on the cellular level. Thus, one approach to detect single cells is X-ray absorption-based CT, where cells are labeled with a dense, opaque material providing the required contrast for CT imaging. Within the present work, a novel cell-labeling method has been developed showing the feasibility of labeling fixed cells with iron oxide (FeO) particles for subsequent CT imaging and quantitative morphometry. A biotin-streptavidin detection system was exploited to bind FeO particles to its target endothelial cells. The binding of the particles was predominantly close to the cell centers on 2D surfaces as shown by light microscopy, scanning electron microscopy, and CT. When cells were cultured on porous, 3D polyurethane surfaces, significantly more FeO particles were detected compared with surfaces without cells and FeO particle labeling using CT. Here, we report on the implementation and evaluation of a novel cell detection method based on high-resolution CT. This system has potential in cell tracking for 3D in vitro imaging in the future. PMID:21951168

  12. Adaptive optics optical coherence tomography at 120,000 depth scans/s for non-invasive cellular phenotyping of the living human retina

    PubMed Central

    Torti, Cristiano; Považay, Boris; Hofer, Bernd; Unterhuber, Angelika; Carroll, Joseph; Ahnelt, Peter Kurt; Drexler, Wolfgang

    2012-01-01

    This paper presents a successful combination of ultra-high speed (120,000 depth scans/s), ultra-high resolution optical coherence tomography with adaptive optics and an achromatizing lens for compensation of monochromatic and longitudinal chromatic ocular aberrations, respectively, allowing for non-invasive volumetric imaging in normal and pathologic human retinas at cellular resolution. The capability of this imaging system is demonstrated here through preliminary studies by probing cellular intraretinal structures that have not been accessible so far with in vivo, non-invasive, label-free imaging techniques, including pigment epithelial cells, micro-vasculature of the choriocapillaris, single nerve fibre bundles and collagenous plates of the lamina cribrosa in the optic nerve head. In addition, the volumetric extent of cone loss in two colour-blinds could be quantified for the first time. This novel technique provides opportunities to enhance the understanding of retinal pathogenesis and early diagnosis of retinal diseases. PMID:19997159

  13. 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

  14. Volumetric Light-Field Excitation.

    PubMed

    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

  15. 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.

  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. Combined Volumetric and Surface Registration

    PubMed Central

    Zöllei, Lilla; Fischl, Bruce

    2009-01-01

    In this paper, we propose a novel method for the registration of volumetric images of the brain that optimizes the alignment of both cortical and subcortical structures. In order to achieve this, relevant geometrical information is extracted from a surface-based morph and diffused into the volume using the Navier operator of elasticity, resulting in a volumetric warp that aligns cortical folding patterns. This warp field is then refined with an intensity driven optical flow procedure that registers noncortical regions, while preserving the cortical alignment. The result is a combined surface and volume morph (CVS) that accurately registers both cortical and subcortical regions, establishing a single coordinate system suitable for the entire brain. PMID:19273000

  18. 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. PMID:25614100

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

    PubMed

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

    2016-03-01

    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

  20. 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

  1. 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

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

    PubMed

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

    2015-08-01

    In vivo imaging at high spatiotemporal resolution is key to the understanding of complex biological systems. We integrated an optical phase-locked ultrasound lens into a two-photon fluorescence microscope and achieved microsecond-scale axial scanning, thus enabling volumetric imaging at tens of hertz. We applied this system to multicolor volumetric imaging of processes sensitive to motion artifacts, including calcium dynamics in behaving mouse brain and transient morphology changes and trafficking of immune cells. PMID:26167641

  3. Seismic volumetric flattening and segmentation

    NASA Astrophysics Data System (ADS)

    Lomask, Jesse

    Two novel algorithms provide seismic interpretation solutions that use the full dimensionality of the data. The first is volumetric flattening and the second is image segmentation for tracking salt boundaries. Volumetric flattening is an efficient full-volume automatic dense-picking method applied to seismic data. First local dips (step-outs) are calculated over the entire seismic volume. The dips are then resolved into time shifts (or depth shifts) in a least-squares sense. To handle faults (discontinuous reflections), I apply a weighted inversion scheme. Additional information is incorporated in this flattening algorithm as geological constraints. The method is tested successfully on both synthetic and field data sets of varying degrees of complexity including salt piercements, angular unconformities, and laterally limited faults. The second full-volume interpretation method uses normalized cuts image segmentation to track salt interfaces. I apply a modified version of the normalized cuts image segmentation (NCIS) method to partition seismic images along salt interfaces. The method is capable of tracking interfaces that are not continuous, where conventional horizon tracking algorithms may fail. This method partitions the seismic image into two groups. One group is inside the salt body and the other is outside. Where the two groups meet is the salt boundary. By imposing bounds and by distributing the algorithm on a parallel cluster, I significantly increase efficiency and robustness. This method is demonstrated to be effective on both 2D and 3D seismic data sets.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. High-throughput subtomogram alignment and classification by Fourier space constrained fast volumetric matching

    PubMed Central

    Xu, Min; Beck, Martin; Alber, Frank

    2013-01-01

    Cryo-electron tomography allows the visualization of macromolecular complexes in their cellular environments in close-to-live conditions. The nominal resolution of subtomograms can be significantly increased when individual subtomograms of the same kind are aligned and averaged. A vital step for such a procedure are algorithms that speedup subtomogram alignment and improve accuracy for reference-free subtomogram classification, which will facilitate automation of tomography analysis and overall high throughput in the data processing. In this paper, we propose a fast rotational alignment method that uses the Fourier equivalent form of a popular constrained correlation measure that considers missing wedge corrections and density variances in the subtomograms. The fast rotational search is based on 3D volumetric matching, which significantly improves the rotational alignment accuracy in particular for highly distorted subtomograms with low SNR and tilt angle ranges in comparison to a fast rotational alignment based on matching of projected 2D spherical images. We further integrate our fast rotational alignment method in a reference free iterative subtomogram classification scheme, and propose a local feature enhancement strategy in the classification process. We can demonstrate that the automatic method can be used to successfully classify a large number of experimental subtomograms without the need of a reference structure. PMID:22420977

  11. 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.

  12. 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

  13. Volumetric imaging of the auroral ionosphere: Initial results from PFISR

    NASA Astrophysics Data System (ADS)

    Semeter, Joshua; Butler, Thomas; Heinselman, Craig; Nicolls, Michael; Kelly, John; Hampton, Donald

    2009-05-01

    The Poker Flat Incoherent Scatter Radar (PFISR) is the first dedicated ISR built with an electronically steerable array. This paper demonstrates the capabilities of PFISR for producing three-dimensional volumetric images of E-region ionization patterns produced by the aurora. The phase table was configured to cycle through 121 beam positions arranged in an 11×11 grid. A 13-baud Barker coded pulse was used, which provided ~1.5-km range resolution out to a maximum range of 250 km. Backscattered power was converted to electron density by correcting for path loss and applying the Buneman approximation assuming equal electron and ion temperatures. The results were then interpolated onto a three-dimensional cartesian grid. Volumetric images are presented at 5-min, 1-min, and 14.6-s integration times (corresponding to 960, 192, and 48 pulses-per-position, respectively) to illustrate the tradeoff between spatio-temporal resolution and data quality. At 14.6 s cadence, variability in plasma density within the volume appears to be fully resolved in space and time, a result that is supported by both observational evidence and theoretical predictions of ionospheric response times. Some potential applications of this mode for studying magnetosphere-ionosphere interactions in the auroral zone are discussed.

  14. Performance-scalable volumetric data classification for online industrial inspection

    NASA Astrophysics Data System (ADS)

    Abraham, Aby J.; Sadki, Mustapha; Lea, R. M.

    2002-03-01

    Non-intrusive inspection and non-destructive testing of manufactured objects with complex internal structures typically requires the enhancement, analysis and visualization of high-resolution volumetric data. Given the increasing availability of fast 3D scanning technology (e.g. cone-beam CT), enabling on-line detection and accurate discrimination of components or sub-structures, the inherent complexity of classification algorithms inevitably leads to throughput bottlenecks. Indeed, whereas typical inspection throughput requirements range from 1 to 1000 volumes per hour, depending on density and resolution, current computational capability is one to two orders-of-magnitude less. Accordingly, speeding up classification algorithms requires both reduction of algorithm complexity and acceleration of computer performance. A shape-based classification algorithm, offering algorithm complexity reduction, by using ellipses as generic descriptors of solids-of-revolution, and supporting performance-scalability, by exploiting the inherent parallelism of volumetric data, is presented. A two-stage variant of the classical Hough transform is used for ellipse detection and correlation of the detected ellipses facilitates position-, scale- and orientation-invariant component classification. Performance-scalability is achieved cost-effectively by accelerating a PC host with one or more COTS (Commercial-Off-The-Shelf) PCI multiprocessor cards. Experimental results are reported to demonstrate the feasibility and cost-effectiveness of the data-parallel classification algorithm for on-line industrial inspection applications.

  15. 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

  16. 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

  17. Volumetric retinal fluorescence microscopic imaging with extended depth of field

    NASA Astrophysics Data System (ADS)

    Li, Zengzhuo; Fischer, Andrew; Li, Wei; Li, Guoqiang

    2016-03-01

    Wavefront-engineered microscope with greatly extended depth of field (EDoF) is designed and demonstrated for volumetric imaging with near-diffraction limited optical performance. A bright field infinity-corrected transmissive/reflective light microscope is built with Kohler illumination. A home-made phase mask is placed in between the objective lens and the tube lens for ease of use. General polynomial function is adopted in the design of the phase plate for robustness and custom merit function is used in Zemax for optimization. The resulting EDoF system achieves an engineered point spread function (PSF) that is much less sensitive to object depth variation than conventional systems and therefore 3D volumetric information can be acquired in a single frame with expanded tolerance of defocus. In Zemax simulation for a setup using 32X objective (NA = 0.6), the EDoF is 20μm whereas a conventional one has a DoF of 1.5μm, indicating a 13 times increase. In experiment, a 20X objective lens with NA = 0.4 was used and the corresponding phase plate was designed and fabricated. Retinal fluorescence images of the EDoF microscope using passive adaptive optical phase element illustrate a DoF around 100μm and it is able to recover the volumetric fluorescence images that are almost identical to in-focus images after post processing. The image obtained from the EDoF microscope is also better in resolution and contrast, and the retinal structure is better defined. Hence, due to its high tolerance of defocus and fine restored image quality, EDoF optical systems have promising potential in consumer portable medical imaging devices where user's ability to achieve focus is not optimal, and other medical imaging equipment where achieving best focus is not a necessary.

  18. Volumetric imaging with an amplitude-steered array.

    PubMed

    Frazier, Catherine H; Hughes, W Jack; O'Brien, William D

    2002-12-01

    Volumetric acoustic imaging is desirable for the visualization of underwater objects and structures; however, the implementation of a volumetric imaging system is difficult due to the high channel count of a fully populated two-dimensional array. Recently, a linear amplitude-steered array with a reduced electronics requirement was presented, which is capable of collecting a two-dimensional set of data with a single transmit pulse. In this study, we demonstrate the use of the linear amplitude-steered array and associated image formation algorithms for collecting and displaying volumetric data; that is, proof of principle of the amplitude-steering concept and the associated image formation algorithms is demonstrated. Range and vertical position are obtained by taking advantage of the frequency separation of a vertical linear amplitude-steered array. The third dimension of data is obtained by rotating the array such that the mainlobe is mechanically steered in azimuth. Data are collected in a water tank at the Pennsylvania State University Applied Research Laboratory for two targets: a ladder and three pipes. These data are the first experimental data collected with an amplitude-steered array for the purposes of imaging. The array is 10 cm in diameter and is operated in the frequency range of 80 to 304 kHz. Although the array is small for high-resolution imaging at these frequencies, the rungs of the ladder are recognizable in the images. The three pipes are difficult to discern in two of the projection images; however, the pipes separated in range are clear in the image showing vertical position versus range. The imaging concept is demonstrated on measured data, and the simulations agree well with the experimental results. PMID:12508995

  19. Volumetric imaging with an amplitude-steered array

    NASA Astrophysics Data System (ADS)

    Frazier, Catherine H.; Hughes, W. Jack; O'Brien, William D.

    2002-12-01

    Volumetric acoustic imaging is desirable for the visualization of underwater objects and structures; however, the implementation of a volumetric imaging system is difficult due to the high channel count of a fully populated two-dimensional array. Recently, a linear amplitude-steered array with a reduced electronics requirement was presented, which is capable of collecting a two-dimensional set of data with a single transmit pulse. In this study, we demonstrate the use of the linear amplitude-steered array and associated image formation algorithms for collecting and displaying volumetric data; that is, proof of principle of the amplitude-steering concept and the associated image formation algorithms is demonstrated. Range and vertical position are obtained by taking advantage of the frequency separation of a vertical linear amplitude-steered array. The third dimension of data is obtained by rotating the array such that the mainlobe is mechanically steered in azimuth. Data are collected in a water tank at the Pennsylvania State University Applied Research Laboratory for two targets: a ladder and three pipes. These data are the first experimental data collected with an amplitude-steered array for the purposes of imaging. The array is 10 cm in diameter and is operated in the frequency range of 80 to 304 kHz. Although the array is small for high-resolution imaging at these frequencies, the rungs of the ladder are recognizable in the images. The three pipes are difficult to discern in two of the projection images; however, the pipes separated in range are clear in the image showing vertical position versus range. The imaging concept is demonstrated on measured data, and the simulations agree well with the experimental results.

  20. Volumetric display based on multiple mini-projectors and a rotating screen

    NASA Astrophysics Data System (ADS)

    Song, Weitao; Zhu, Qiudong; Huang, Tao; Liu, Yue; Wang, Yongtian

    2015-01-01

    A method has been proposed to realize a transparent volumetric display using multiple mini-projectors and a rotating screen. Correct two-dimensional cross-sectional images are projected on a bidirectional scattering projection screen, which rotates to form a three-dimensional (3-D) image due to human vision persistence. An illumination subsystem is designed to ensure the accurate synchronization between the projectors and the rotating screen. Therefore, low-speed and low-cost miniature display devices can be used in the mini-projectors to realize dynamic volumetric imaging, which can satisfy all criteria of real 3-D vision with full color and high resolution. Experimental results of volumetric imaging realized by this method are also presented.

  1. 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.

  2. 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.

  3. 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

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

    PubMed Central

    Chockalingam, Ammaiyappan; Duraiswamy, Ranganathan; Jagadeesan, Madhavan

    2016-01-01

    Background: 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. Materials and Methods: 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. Results: 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. Clinical Significance: 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. PMID:27185993

  5. 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.

  6. Clinical Applications of Volumetric Modulated Arc Therapy

    SciTech Connect

    Matuszak, Martha M.; Yan Di; Grills, Inga; Martinez, Alvaro

    2010-06-01

    Purpose: To present treatment planning case studies for several treatment sites for which volumetric modulated arc therapy (VMAT) could have a positive impact; and to share an initial clinical experience with VMAT for stereotactic body radiotherapy (SBRT). Methods and Materials: Four case studies are presented to show the potential benefit of VMAT compared with conformal and intensity-modulated radiotherapy (IMRT) techniques in pediatric cancer, bone marrow-sparing whole-abdominopelvic irradiation (WAPI), and SBRT of the lung and spine. Details of clinical implementation of VMAT for SBRT are presented. The VMAT plans are compared with conventional techniques in terms of dosimetric quality and delivery efficiency. Results: Volumetric modulated arc therapy reduced the treatment time of spine SBRT by 37% and improved isodose conformality. Conformal and VMAT techniques for lung SBRT had similar dosimetric quality, but VMAT had improved target coverage and took 59% less time to deliver, although monitor units were increased by 5%. In a complex pediatric pelvic example, VMAT reduced treatment time by 78% and monitor units by 25% compared with IMRT. A double-isocenter VMAT technique for WAPI can spare bone marrow while maintaining good delivery efficiency. Conclusions: Volumetric modulated arc therapy is a new technology that may benefit different patient populations, including pediatric cancer patients and those undergoing concurrent chemotherapy and WAPI. Volumetric modulated arc therapy has been used and shown to be beneficial for significantly improving delivery efficiency of lung and spine SBRT.

  7. 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…

  8. 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

  9. Volumetric HiLo microscopy employing an electrically tunable lens.

    PubMed

    Philipp, Katrin; Smolarski, André; Koukourakis, Nektarios; Fischer, Andreas; Stürmer, Moritz; Wallrabe, Ulrike; Czarske, Jürgen W

    2016-06-27

    Electrically tunable lenses exhibit strong potential for fast motion-free axial scanning in a variety of microscopes. However, they also lead to a degradation of the achievable resolution because of aberrations and misalignment between illumination and detection optics that are induced by the scan itself. Additionally, the typically nonlinear relation between actuation voltage and axial displacement leads to over- or under-sampled frame acquisition in most microscopic techniques because of their static depth-of-field. To overcome these limitations, we present an Adaptive-Lens-High-and-Low-frequency (AL-HiLo) microscope that enables volumetric measurements employing an electrically tunable lens. By using speckle-patterned illumination, we ensure stability against aberrations of the electrically tunable lens. Its depth-of-field can be adjusted a-posteriori and hence enables to create flexible scans, which compensates for irregular axial measurement positions. The adaptive HiLo microscope provides an axial scanning range of 1 mm with an axial resolution of about 4 μm and sub-micron lateral resolution over the full scanning range. Proof of concept measurements at home-built specimens as well as zebrafish embryos with reporter gene-driven fluorescence in the thyroid gland are shown. PMID:27410654

  10. Volumetric PIV with a Plenoptic Camera

    NASA Astrophysics Data System (ADS)

    Thurow, Brian; Fahringer, Tim

    2012-11-01

    Plenoptic cameras have received attention recently due to their ability to computationally refocus an image after it has been acquired. We describe the development of a robust, economical and easy-to-use volumetric PIV technique using a unique plenoptic camera built in our laboratory. The tomographic MART algorithm is used to reconstruct pairs of 3D particle volumes with velocity determined using conventional cross-correlation techniques. 3D/3C velocity measurements (volumetric dimensions of 2 . 8 ' ' × 1 . 9 ' ' × 1 . 6 ' ') of a turbulent boundary layer produced on the wall of a conventional wind tunnel are presented. This work has been supported by the Air Force Office of Scientific Research,(Grant #FA9550-100100576).

  11. Cellular resilience.

    PubMed

    Smirnova, Lena; Harris, Georgina; Leist, Marcel; Hartung, Thomas

    2015-01-01

    Cellular resilience describes the ability of a cell to cope with environmental changes such as toxicant exposure. If cellular metabolism does not collapse directly after the hit or end in programmed cell death, the ensuing stress responses promote a new homeostasis under stress. The processes of reverting "back to normal" and reversal of apoptosis ("anastasis") have been studied little at the cellular level. Cell types show astonishingly similar vulnerability to most toxicants, except for those that require a very specific target, metabolism or mechanism present only in specific cell types. The majority of chemicals triggers "general cytotoxicity" in any cell at similar concentrations. We hypothesize that cells differ less in their vulnerability to a given toxicant than in their resilience (coping with the "hit"). In many cases, cells do not return to the naive state after a toxic insult. The phenomena of "pre-conditioning", "tolerance" and "hormesis" describe this for low-dose exposures to toxicants that render the cell more resistant to subsequent hits. The defense and resilience programs include epigenetic changes that leave a "memory/scar" - an alteration as a consequence of the stress the cell has experienced. These memories might have long-term consequences, both positive (resistance) and negative, that contribute to chronic and delayed manifestations of hazard and, ultimately, disease. This article calls for more systematic analyses of how cells cope with toxic perturbations in the long-term after stressor withdrawal. A technical prerequisite for these are stable (organotypic) cultures and a characterization of stress response molecular networks. PMID:26536287

  12. Low-Pass Filtered Volumetric Shadows.

    PubMed

    Ament, Marco; Sadlo, Filip; Dachsbacher, Carsten; Weiskopf, Daniel

    2014-12-01

    We present a novel and efficient method to compute volumetric soft shadows for interactive direct volume visualization to improve the perception of spatial depth. By direct control of the softness of volumetric shadows, disturbing visual patterns due to hard shadows can be avoided and users can adapt the illumination to their personal and application-specific requirements. We compute the shadowing of a point in the data set by employing spatial filtering of the optical depth over a finite area patch pointing toward each light source. Conceptually, the area patch spans a volumetric region that is sampled with shadow rays; afterward, the resulting optical depth values are convolved with a low-pass filter on the patch. In the numerical computation, however, to avoid expensive shadow ray marching, we show how to align and set up summed area tables for both directional and point light sources. Once computed, the summed area tables enable efficient evaluation of soft shadows for each point in constant time without shadow ray marching and the softness of the shadows can be controlled interactively. We integrated our method in a GPU-based volume renderer with ray casting from the camera, which offers interactive control of the transfer function, light source positions, and viewpoint, for both static and time-dependent data sets. Our results demonstrate the benefit of soft shadows for visualization to achieve user-controlled illumination with many-point lighting setups for improved perception combined with high rendering speed. PMID:26356957

  13. Thousand-fold volumetric concentration of live cells with a recirculating acoustofluidic device.

    PubMed

    Jakobsson, Ola; Oh, Seung Soo; Antfolk, Maria; Eisenstein, Michael; Laurell, Thomas; Soh, H Tom

    2015-08-18

    The ability to concentrate cells from dilute samples into smaller volumes is an essential process step for most biological assays. Volumetric concentration is typically achieved via centrifugation, but this technique is not well suited for handling small number of cells, especially outside of the laboratory setting. In this work, we describe a novel device that combines acoustofluidics with a recirculating architecture to achieve >1000-fold enrichment of cells in a label-free manner, at high volumetric throughput (>500 μL min(-1)) and with high recovery (>98.7%). We demonstrate that our device can be used with a wide variety of different cell types and show that this concentration strategy does not affect cell viability. Importantly, our device could be readily adopted to serve as a "sample preparation" module that can be integrated with other microfluidic devices to allow analysis of dilute cellular samples in large volumes. PMID:26226316

  14. Quenching correction for volumetric scintillation dosimetry of proton beams

    PubMed Central

    Robertson, Daniel; Mirkovic, Dragan; Sahoo, Narayan; Beddar, Sam

    2013-01-01

    Purpose Volumetric scintillation dosimetry has the potential to provide fast, high-resolution, three-dimensional radiation dosimetry. However, scintillators exhibit a nonlinear response at the high linear energy transfer (LET) values characteristic of proton Bragg peaks. The purpose of this study was to develop a quenching correction method for volumetric scintillation dosimetry of proton beams. Methods Scintillation light from a miniature liquid scintillator detector was measured along the central axis of a 161.6-MeV proton pencil beam. Three-dimensional dose and LET distributions were calculated for 85.6-, 100.9-, 144.9-, and 161.6-MeV beams using a validated Monte Carlo model. LET values were also calculated using an analytical formula. A least-squares fit to the data established the empirical parameters of a quenching correction model. The light distribution in a tank of liquid scintillator was measured with a CCD camera at all four beam energies. The quenching model and LET data were used to correct the measured light distribution. Results The calculated and measured Bragg peak heights agreed within ±3% for all energies except 85.6 MeV, where the agreement was within ±10%. The quality of the quenching correction was poorer for sharp low-energy Bragg peaks because of blurring and detector size effects. The corrections performed using analytical LET values resulted in doses within 1% of those obtained using Monte Carlo LET values. Conclusion The proposed method can correct for quenching with sufficient accuracy for dosimetric purposes. The required LET values may be computed effectively using Monte Carlo or analytical methods. Future detectors should improve blurring correction methods and optimize the pixel size to improve accuracy for low-energy Bragg peaks. PMID:23257200

  15. Efficient volumetric estimation from plenoptic data

    NASA Astrophysics Data System (ADS)

    Anglin, Paul; Reeves, Stanley J.; Thurow, Brian S.

    2013-03-01

    The commercial release of the Lytro camera, and greater availability of plenoptic imaging systems in general, have given the image processing community cost-effective tools for light-field imaging. While this data is most commonly used to generate planar images at arbitrary focal depths, reconstruction of volumetric fields is also possible. Similarly, deconvolution is a technique that is conventionally used in planar image reconstruction, or deblurring, algorithms. However, when leveraged with the ability of a light-field camera to quickly reproduce multiple focal planes within an imaged volume, deconvolution offers a computationally efficient method of volumetric reconstruction. Related research has shown than light-field imaging systems in conjunction with tomographic reconstruction techniques are also capable of estimating the imaged volume and have been successfully applied to particle image velocimetry (PIV). However, while tomographic volumetric estimation through algorithms such as multiplicative algebraic reconstruction techniques (MART) have proven to be highly accurate, they are computationally intensive. In this paper, the reconstruction problem is shown to be solvable by deconvolution. Deconvolution offers significant improvement in computational efficiency through the use of fast Fourier transforms (FFTs) when compared to other tomographic methods. This work describes a deconvolution algorithm designed to reconstruct a 3-D particle field from simulated plenoptic data. A 3-D extension of existing 2-D FFT-based refocusing techniques is presented to further improve efficiency when computing object focal stacks and system point spread functions (PSF). Reconstruction artifacts are identified; their underlying source and methods of mitigation are explored where possible, and reconstructions of simulated particle fields are provided.

  16. 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.

  17. 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.

  18. FELIX: a volumetric 3D laser display

    NASA Astrophysics Data System (ADS)

    Bahr, Detlef; Langhans, Knut; Gerken, Martin; Vogt, Carsten; Bezecny, Daniel; Homann, Dennis

    1996-03-01

    In this paper, an innovative approach of a true 3D image presentation in a space filling, volumetric laser display will be described. The introduced prototype system is based on a moving target screen that sweeps the display volume. Net result is the optical equivalent of a 3D array of image points illuminated to form a model of the object which occupies a physical space. Wireframe graphics are presented within the display volume which a group of people can walk around and examine simultaneously from nearly any orientation and without any visual aids. Further to the detailed vector scanning mode, a raster scanned system and a combination of both techniques are under development. The volumetric 3D laser display technology for true reproduction of spatial images can tremendously improve the viewers ability to interpret data and to reliably determine distance, shape and orientation. Possible applications for this development range from air traffic control, where moving blips of light represent individual aircrafts in a true to scale projected airspace of an airport, to various medical applications (e.g. electrocardiography, computer-tomography), to entertainment and education visualization as well as imaging in the field of engineering and Computer Aided Design.

  19. 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).

  20. Volumetric capnography in the mechanically ventilated patient.

    PubMed

    Blanch, L; Romero, P V; Lucangelo, U

    2006-06-01

    Expiratory capnogram provides qualitative information on the waveform patterns associated with mechanical ventilation and quantitative estimation of expired CO2. Volumetric capnography simultaneously measures expired CO2 and tidal volume and allows identification of CO2 from 3 sequential lung compartments: apparatus and anatomic dead space, from progressive emptying of alveoli and alveolar gas. Lung heterogeneity creates regional differences in CO2 concentration and sequential emptying contributes to the rise of the alveolar plateau and to the steeper the expired CO2 slope. The concept of dead space accounts for those lung areas that are ventilated but not perfused. In patients with sudden pulmonary vascular occlusion due to pulmonary embolism, the resultant high V/Q mismatch produces an increase in alveolar dead space. Calculations derived from volumetric capnography are useful to suspect pulmonary embolism at the bedside. Alveolar dead space is large in acute lung injury and when the effect of positive end-expiratory pressure (PEEP) is to recruit collapsed lung units resulting in an improvement of oxygenation, alveolar dead space may decrease, whereas PEEP-induced overdistension tends to increase alveolar dead space. Finally, measurement of physiologic dead space and alveolar ejection volume at admission or the trend during the first 48 hours of mechanical ventilation might provide useful information on outcome of critically ill patients with acute lung injury or acute respiratory distress syndrome. PMID:16682932

  1. Adaptive controller for volumetric display of neuroimaging studies

    NASA Astrophysics Data System (ADS)

    Bleiberg, Ben; Senseney, Justin; Caban, Jesus

    2014-03-01

    Volumetric display of medical images is an increasingly relevant method for examining an imaging acquisition as the prevalence of thin-slice imaging increases in clinical studies. Current mouse and keyboard implementations for volumetric control provide neither the sensitivity nor specificity required to manipulate a volumetric display for efficient reading in a clinical setting. Solutions to efficient volumetric manipulation provide more sensitivity by removing the binary nature of actions controlled by keyboard clicks, but specificity is lost because a single action may change display in several directions. When specificity is then further addressed by re-implementing hardware binary functions through the introduction of mode control, the result is a cumbersome interface that fails to achieve the revolutionary benefit required for adoption of a new technology. We address the specificity versus sensitivity problem of volumetric interfaces by providing adaptive positional awareness to the volumetric control device by manipulating communication between hardware driver and existing software methods for volumetric display of medical images. This creates a tethered effect for volumetric display, providing a smooth interface that improves on existing hardware approaches to volumetric scene manipulation.

  2. 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.

  3. A method for generating volumetric fault zone grids for pillar gridded reservoir models

    NASA Astrophysics Data System (ADS)

    Qu, Dongfang; Røe, Per; Tveranger, Jan

    2015-08-01

    The internal structure and petrophysical property distribution of fault zones are commonly exceedingly complex compared to the surrounding host rock from which they are derived. This in turn produces highly complex fluid flow patterns which affect petroleum migration and trapping as well as reservoir behavior during production and injection. Detailed rendering and forecasting of fluid flow inside fault zones require high-resolution, explicit models of fault zone structure and properties. A fundamental requirement for achieving this is the ability to create volumetric grids in which modeling of fault zone structures and properties can be performed. Answering this need, a method for generating volumetric fault zone grids which can be seamlessly integrated into existing standard reservoir modeling tools is presented. The algorithm has been tested on a wide range of fault configurations of varying complexity, providing flexible modeling grids which in turn can be populated with fault zone structures and properties.

  4. 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.

  5. Volumetric techniques: three-dimensional midface modeling

    PubMed Central

    Pierzchała, Ewa; Placek, Waldemar

    2014-01-01

    Aging is a complex process caused by many factors. The most important factors include exposure to UV radiation, smoking, facial muscle movement, gravity, loss and displacement of fat and bone resorption. As a symptom of aging, face loses elasticity, volume and cheerful look. While changing face proportions, the dominant part of a face is its bottom instead of the mid part. The use of three-dimensional face modelling techniques, particularly the mid-face – tear through and cheeks, restores the skin firmness, volume and healthy look. For this purpose the hyaluronic acid is used, calcium hydroxyapatite, and L-polylactic acid fillers. Volumetric techniques require precision and proper selection of the filling agent to give a sense of satisfaction to both the patient and the doctor. PMID:25610354

  6. Progressive Compression of Volumetric Subdivision Meshes

    SciTech Connect

    Laney, D; Pascucci, V

    2004-04-16

    We present a progressive compression technique for volumetric subdivision meshes based on the slow growing refinement algorithm. The system is comprised of a wavelet transform followed by a progressive encoding of the resulting wavelet coefficients. We compare the efficiency of two wavelet transforms. The first transform is based on the smoothing rules used in the slow growing subdivision technique. The second transform is a generalization of lifted linear B-spline wavelets to the same multi-tier refinement structure. Direct coupling with a hierarchical coder produces progressive bit streams. Rate distortion metrics are evaluated for both wavelet transforms. We tested the practical performance of the scheme on synthetic data as well as data from laser indirect-drive fusion simulations with multiple fields per vertex. Both wavelet transforms result in high quality trade off curves and produce qualitatively good coarse representations.

  7. Interactive stereoscopic rendering of volumetric environments.

    PubMed

    Wan, Ming; Zhang, Nan; Qu, Huamin; Kaufman, Arie E

    2004-01-01

    We present an efficient stereoscopic rendering algorithm supporting interactive navigation through large-scale 3D voxel-based environments. In this algorithm, most of the pixel values of the right image are derived from the left image by a fast 3D warping based on a specific stereoscopic projection geometry. An accelerated volumetric ray casting then fills the remaining gaps in the warped right image. Our algorithm has been parallelized on a multiprocessor by employing effective task partitioning schemes and achieved a high cache coherency and load balancing. We also extend our stereoscopic rendering to include view-dependent shading and transparency effects. We have applied our algorithm in two virtual navigation systems, flythrough over terrain and virtual colonoscopy, and reached interactive stereoscopic rendering rates of more than 10 frames per second on a 16-processor SGI Challenge. PMID:15382695

  8. Live volumetric imaging (LVI) intracardiac ultrasound catheter.

    PubMed

    Dausch, David E; Castellucci, John B; Gilchrist, Kristin H; Carlson, James B; Hall, Stephen D; von Ramm, Olaf T

    2013-01-01

    The Live Volumetric Imaging (LVI) catheter is capable of real-time 3D intracardiac echo (ICE) imaging, uniquely providing full volume sectors with deep penetration depth and high volume frame rate. The key enabling technology in this catheter is an integrated piezoelectric micromachined ultrasound transducer (pMUT), a novel matrix phased array transducer fabricated using semiconductor microelectromechanical systems (MEMS) manufacturing techniques. This technology innovation may enable better image guidance to improve accuracy, reduce risk, and reduce procedure time for transcatheter intracardiac therapies which are currently done with limited direct visualization of the endocardial tissue. Envisioned applications for LVI include intraprocedural image guidance of cardiac ablation therapies as well as transcatheter mitral and aortic valve repair. PMID:23773496

  9. Functional transcranial brain imaging by optical-resolution photoacoustic microscopy

    NASA Astrophysics Data System (ADS)

    Hu, Song; Maslov, Konstantin; Tsytsarev, Vassiliy; Wang, Lihong V.

    2009-07-01

    Optical-resolution photoacoustic microscopy (OR-PAM) is applied to functional brain imaging in living mice. A near-diffraction-limited bright-field optical illumination is employed to achieve micrometer lateral resolution, and a dual-wavelength measurement is utilized to extract the blood oxygenation information. The variation in hemoglobin oxygen saturation (sO2) along vascular branching has been imaged in a precapillary arteriolar tree and a postcapillary venular tree, respectively. To the best of our knowledge, this is the first report on in vivo volumetric imaging of brain microvascular morphology and oxygenation down to single capillaries through intact mouse skulls. It is anticipated that: (i) chronic imaging enabled by this minimally invasive procedure will advance the study of cortical plasticity and neurological diseases; (ii) revealing the neuroactivity-dependent changes in hemoglobin concentration and oxygenation will facilitate the understanding of neurovascular coupling at the capillary level; and (iii) combining functional OR-PAM and high-resolution blood flowmetry will have the potential to explore cellular pathways of brain energy metabolism.

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

    PubMed Central

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

    2015-01-01

    Objective To determine normative ranges for fetal ocular biometrics between 19 and 38 weeks gestational age (GA) using volumetric MRI reconstruction. Method 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). Results All biometry correlated with GA (Volume, 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. Conclusion Orbital volume had the greatest correlation with GA, though 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. PMID:25601041

  11. 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

  12. 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.

  13. Volumetric Rendering of Geophysical Data on Adaptive Wavelet Grid

    NASA Astrophysics Data System (ADS)

    Vezolainen, A.; Erlebacher, G.; Vasilyev, O.; Yuen, D. A.

    2005-12-01

    Numerical modeling of geological phenomena frequently involves processes across a wide range of spatial and temporal scales. In the last several years, transport phenomena governed by the Navier-Stokes equations have been simulated in wavelet space using second generation wavelets [1], and most recently on fully adaptive meshes. Our objective is to visualize this time-dependent data using volume rendering while capitalizing on the available sparse data representation. We present a technique for volumetric ray casting of multi-scale datasets in wavelet space. Rather of working with the wavelets at the finest possible resolution, we perform a partial inverse wavelet transform as a preprocessing step to obtain scaling functions on a uniform grid at a user-prescribed resolution. As a result, a function in physical space is represented by a superposition of scaling functions on a coarse regular grid and wavelets on an adaptive mesh. An efficient and accurate ray casting algorithm is based just on these scaling functions. Additional detail is added during the ray tracing by taking an appropriate number of wavelets into account based on support overlap with the interpolation point, wavelet amplitude, and other characteristics, such as opacity accumulation (front to back ordering) and deviation from frontal viewing direction. Strategies for hardware implementation will be presented if available, inspired by the work in [2]. We will pressent error measures as a function of the number of scaling and wavelet functions used for interpolation. Data from mantle convection will be used to illustrate the method. [1] Vasilyev, O.V. and Bowman, C., Second Generation Wavelet Collocation Method for the Solution of Partial Differential Equations. J. Comp. Phys., 165, pp. 660-693, 2000. [2] Guthe, S., Wand, M., Gonser, J., and Straßer, W. Interactive rendering of large volume data sets. In Proceedings of the Conference on Visualization '02 (Boston, Massachusetts, October 27 - November

  14. 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

  15. 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.

  16. Volumetric measurement of residual stress using high energy x-ray diffraction

    NASA Astrophysics Data System (ADS)

    Whitesell, R.; McKenna, A.; Wendt, S.; Gray, J.

    2016-02-01

    We present results and recent developments from our laboratory, bench-top high energy x-ray diffraction system (HEXRD), between diffraction energies 50 and 150 KeV, to measure internal strain of moderately sized objects. Traditional x-ray strain measurements are limited to a few microns depth due to the use of Cu Kα1 Mo Kα1 radiation. The use of high energy x-rays for volumetric measurements of strain is typically the domain of synchrotron sources. We discuss the use of industrial 320kVp tube sources to generate a brighter x-ray beam along with a method using the intrinsic 43 eV width of the Kα1 characteristic peak of tungsten to measure volumetric strains in a number of industrially relevant materials. We will present volumetric strain measurements from two examples, first, additive manufacturing (AM) parts with various build configurations and, secondly, residual strain depth profiles from shot peened surface treatments. The spatial resolution of these depth profiles is ˜75 microns. The development of a faster method as compared to energy dispersive or θ-2θ scans is based on the intensity variation measurement of the strain using the aforementioned 43 eV characteristic tungsten kα line. We will present recent results on the development of this new tool and on x-ray diffraction measurements at high energy.

  17. 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.

  18. 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.

  19. An improved tamper detection and localization scheme for volumetric DICOM images.

    PubMed

    Dou, Wenbo; Poh, Chueh Loo; Guan, Yong Liang

    2012-12-01

    The development of teleradiology brings the convenience of global medical record access along with the concerns over the security of medical images transmitted over the open network. With the prevailing adoption of three-dimensional (3-D) imaging modalities, it is vital to develop a security mechanism to provide large volumes of medical images with privacy and reliability. This paper presents the development of a new and improved method of implementing tamper detection and localization based on a fully reversible digital watermarking scheme for the protection of volumetric DICOM images. This tamper detection and localization method utilizes the 3-D property of volumetric data to achieve much faster processing time at both sender and receiver sides without compromising tamper localization accuracy. The performance of the proposed scheme was evaluated by using sample volumetric DICOM images. Results show that the scheme achieved on average about 65 % and 72 % reduction in watermarking and dewatermarking processing time, respectively. For cases where the images had been tampered, it is possible to detect and localize the tampered areas with improved localization resolution in the images using the scheme. PMID:22832896

  20. Autologous Fat Grafting in Facial Volumetric Restoration

    PubMed Central

    Pasquale, Piombino; Gaetano, Marenzi; Giovanni, Dell’Aversana Orabona; Luigi, Califano; Gilberto, Sammartino

    2015-01-01

    Abstract The authors reported their surgical experience about structural fat grafting in the management of facial volumetric deficit. The purpose of this study was to assess the real indications, cosmetic results, complications, and global patient satisfaction of the Coleman technique in redefining facial contours in congenital and postoperative deformities. A retrospective analysis of 32 patients grafted according to Coleman's technique was performed, and the long-term outcomes and patient satisfaction were evaluated. The mean postoperative clinical follow-up was 14 months. The morphological changes were analyzed by comparing the photographic presurgical facial contour and the postoperative correction of soft tissue defects. All consecutive cases reported showed a progressive fat resorption for 3 months after surgery and its stable integration only after this period. Best results were performed in the treatment of genetically determined syndromes, such as the Franceschetti and Romberg syndromes. The authors suggest this surgical technique also for the treatment of unaesthetic cutaneous abscess cavity after incision and drainage. Unsatisfactory outcomes were obtained in the treatment of the posttraumatic facial scar, which needed more surgical procedures. PMID:25974786

  1. Random Volumetric MRI Trajectories via Genetic Algorithms

    PubMed Central

    Curtis, Andrew Thomas; Anand, Christopher Kumar

    2008-01-01

    A pseudorandom, velocity-insensitive, volumetric k-space sampling trajectory is designed for use with balanced steady-state magnetic resonance imaging. Individual arcs are designed independently and do not fit together in the way that multishot spiral, radial or echo-planar trajectories do. Previously, it was shown that second-order cone optimization problems can be defined for each arc independent of the others, that nulling of zeroth and higher moments can be encoded as constraints, and that individual arcs can be optimized in seconds. For use in steady-state imaging, sampling duty cycles are predicted to exceed 95 percent. Using such pseudorandom trajectories, aliasing caused by under-sampling manifests itself as incoherent noise. In this paper, a genetic algorithm (GA) is formulated and numerically evaluated. A large set of arcs is designed using previous methods, and the GA choses particular fit subsets of a given size, corresponding to a desired acquisition time. Numerical simulations of 1 second acquisitions show good detail and acceptable noise for large-volume imaging with 32 coils. PMID:18604305

  2. Iterative reconstruction of volumetric particle distribution

    NASA Astrophysics Data System (ADS)

    Wieneke, Bernhard

    2013-02-01

    For tracking the motion of illuminated particles in space and time several volumetric flow measurement techniques are available like 3D-particle tracking velocimetry (3D-PTV) recording images from typically three to four viewing directions. For higher seeding densities and the same experimental setup, tomographic PIV (Tomo-PIV) reconstructs voxel intensities using an iterative tomographic reconstruction algorithm (e.g. multiplicative algebraic reconstruction technique, MART) followed by cross-correlation of sub-volumes computing instantaneous 3D flow fields on a regular grid. A novel hybrid algorithm is proposed here that similar to MART iteratively reconstructs 3D-particle locations by comparing the recorded images with the projections calculated from the particle distribution in the volume. But like 3D-PTV, particles are represented by 3D-positions instead of voxel-based intensity blobs as in MART. Detailed knowledge of the optical transfer function and the particle image shape is mandatory, which may differ for different positions in the volume and for each camera. Using synthetic data it is shown that this method is capable of reconstructing densely seeded flows up to about 0.05 ppp with similar accuracy as Tomo-PIV. Finally the method is validated with experimental data.

  3. Volumetric depth peeling for medical image display

    NASA Astrophysics Data System (ADS)

    Borland, David; Clarke, John P.; Fielding, Julia R.; TaylorII, Russell M.

    2006-01-01

    Volumetric depth peeling (VDP) is an extension to volume rendering that enables display of otherwise occluded features in volume data sets. VDP decouples occlusion calculation from the volume rendering transfer function, enabling independent optimization of settings for rendering and occlusion. The algorithm is flexible enough to handle multiple regions occluding the object of interest, as well as object self-occlusion, and requires no pre-segmentation of the data set. VDP was developed as an improvement for virtual arthroscopy for the diagnosis of shoulder-joint trauma, and has been generalized for use in other simple and complex joints, and to enable non-invasive urology studies. In virtual arthroscopy, the surfaces in the joints often occlude each other, allowing limited viewpoints from which to evaluate these surfaces. In urology studies, the physician would like to position the virtual camera outside the kidney collecting system and see inside it. By rendering invisible all voxels between the observer's point of view and objects of interest, VDP enables viewing from unconstrained positions. In essence, VDP can be viewed as a technique for automatically defining an optimal data- and task-dependent clipping surface. Radiologists using VDP display have been able to perform evaluations of pathologies more easily and more rapidly than with clinical arthroscopy, standard volume rendering, or standard MRI/CT slice viewing.

  4. 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.

  5. Volumetric imaging system for the ionosphere (VISION)

    NASA Astrophysics Data System (ADS)

    Dymond, Kenneth F.; Budzien, Scott A.; Nicholas, Andrew C.; Thonnard, Stefan E.; Fortna, Clyde B.

    2002-01-01

    The Volumetric Imaging System for the Ionosphere (VISION) is designed to use limb and nadir images to reconstruct the three-dimensional distribution of electrons over a 1000 km wide by 500 km high slab beneath the satellite with 10 km x 10 km x 10 km voxels. The primary goal of the VISION is to map and monitor global and mesoscale (> 10 km) electron density structures, such as the Appleton anomalies and field-aligned irregularity structures. The VISION consists of three UV limb imagers, two UV nadir imagers, a dual frequency Global Positioning System (GPS) receiver, and a coherently emitting three frequency radio beacon. The limb imagers will observe the O II 83.4 nm line (daytime electron density), O I 135.6 nm line (nighttime electron density and daytime O density), and the N2 Lyman-Birge-Hopfield (LBH) bands near 143.0 nm (daytime N2 density). The nadir imagers will observe the O I 135.6 nm line (nighttime electron density and daytime O density) and the N2 LBH bands near 143.0 nm (daytime N2 density). The GPS receiver will monitor the total electron content between the satellite containing the VISION and the GPS constellation. The three frequency radio beacon will be used with ground-based receiver chains to perform computerized radio tomography below the satellite containing the VISION. The measurements made using the two radio frequency instruments will be used to validate the VISION UV measurements.

  6. 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

  7. 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. PMID:27147517

  8. 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.

  9. 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.

  10. 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

  11. Commissioning of Volumetric Modulated Arc Therapy (VMAT)

    SciTech Connect

    Bedford, James L. Warrington, Alan P.

    2009-02-01

    Purpose: Volumetric modulated arc therapy (VMAT) involves the simultaneous use of dynamic multileaf collimator (DMLC) techniques and gantry arcing; appropriate quality assurance is therefore required. This article describes the development and implementation of procedures for commissioning VMAT on a commercial linear accelerator (Elekta PreciseBeam VMAT with MLCi and Beam Modulator heads). Materials and Methods: Tests for beam flatness and symmetry at the variable dose rates required for VMAT were performed. Multileaf collimator (MLC) calibration was investigated using dynamic prescriptions. The cumulative dose delivered by a sliding window aperture was measured and compared with calculated values. Rotational accuracy was evaluated using dynamic prescriptions which required accurate correlated motion of both gantry and MLC leaves. Finally, measured and calculated dose distributions for complete VMAT treatment plans were compared and evaluated. Results: Beam symmetry was found to be better than 3% down to dose rates of 75 MU/min. MLC calibration provided continuity of dose at match planes of better than 4%, which was comparable to interleaf leakage effects. Integrated sliding window doses were within 3% of those calculated. Tests for rotational accuracy showed uniformity of peripheral dose mostly within {+-}4% of local control point dose, or approximately {+-}0.2% of total central dose. A two-arc prostate case showed an absolute dose difference between calculations and measurements of less than 3%, with gamma (3% and 3 mm) of better than 95%. Conclusions: VMAT has been successfully commissioned and has been introduced into clinical use. The Elekta DMLC has also been shown to be suitable for sliding window delivery.

  12. Treatment planning for volumetric modulated arc therapy

    SciTech Connect

    Bedford, James L.

    2009-11-15

    Purpose: Volumetric modulated arc therapy (VMAT) is a specific type of intensity-modulated radiation therapy (IMRT) in which the gantry speed, multileaf collimator (MLC) leaf position, and dose rate vary continuously during delivery. A treatment planning system for VMAT is presented. Methods: Arc control points are created uniformly throughout one or more arcs. An iterative least-squares algorithm is used to generate a fluence profile at every control point. The control points are then grouped and all of the control points in a given group are used to approximate the fluence profiles. A direct-aperture optimization is then used to improve the solution, taking into account the allowed range of leaf motion of the MLC. Dose is calculated using a fast convolution algorithm and the motion between control points is approximated by 100 interpolated dose calculation points. The method has been applied to five cases, consisting of lung, rectum, prostate and seminal vesicles, prostate and pelvic lymph nodes, and head and neck. The resulting plans have been compared with segmental (step-and-shoot) IMRT and delivered and verified on an Elekta Synergy to ensure practicality. Results: For the lung, prostate and seminal vesicles, and rectum cases, VMAT provides a plan of similar quality to segmental IMRT but with faster delivery by up to a factor of 4. For the prostate and pelvic nodes and head-and-neck cases, the critical structure doses are reduced with VMAT, both of these cases having a longer delivery time than IMRT. The plans in general verify successfully, although the agreement between planned and measured doses is not very close for the more complex cases, particularly the head-and-neck case. Conclusions: Depending upon the emphasis in the treatment planning, VMAT provides treatment plans which are higher in quality and/or faster to deliver than IMRT. The scheme described has been successfully introduced into clinical use.

  13. Comprehensive volumetric confocal microscopy with adaptive focusing

    PubMed Central

    Kang, DongKyun; Yoo, Hongki; Jillella, Priyanka; Bouma, Brett E.; Tearney, Guillermo J.

    2011-01-01

    Comprehensive microscopy of distal esophagus could greatly improve the screening and surveillance of esophageal diseases such as Barrett’s esophagus by providing histomorphologic information over the entire region at risk. Spectrally encoded confocal microscopy (SECM) is a high-speed reflectance confocal microscopy technology that can be configured to image the entire distal esophagus by helically scanning the beam using optics within a balloon-centering probe. It is challenging to image the human esophagus in vivo with balloon-based SECM, however, because patient motion and anatomic tissue surface irregularities decenter the optics, making it difficult to keep the focus at a predetermined location within the tissue as the beam is scanned. In this paper, we present a SECM probe equipped with an adaptive focusing mechanism that can compensate for tissue surface irregularity and dynamic focal variation. A tilted arrangement of the objective lens is employed in the SECM probe to provide feedback signals to an adaptive focusing mechanism. The tilted configuration also allows the probe to obtain reflectance confocal data from multiple depth levels, enabling the acquisition of three-dimensional volumetric data during a single scan of the probe. A tissue phantom with a surface area of 12.6 cm2 was imaged using the new SECM probe, and 8 large-area reflectance confocal microscopy images were acquired over the depth range of 56 μm in 20 minutes. Large-area SECM images of excised swine small intestine tissue were also acquired, enabling the visualization of villous architecture, epithelium, and lamina propria. The adaptive focusing mechanism was demonstrated to enable acquisition of in-focus images even when the probe was not centered and the tissue surface was irregular. PMID:21698005

  14. Volumetric interpretation of protein adsorption kinetics

    NASA Astrophysics Data System (ADS)

    Barnthip, Naris

    Protein adsorption is believed to be a very important factor ultimately leading to a predictive basis for biomaterials design and improving biocompatibility. Standard adsorption theories are modified to accommodate experimental observations. Adsorption from single-protein solutions and competitive adsorption from binary solutions are mainly considered. The standard solution-depletion method of measuring protein adsorption is implemented with SDS-gel electrophoresis as a multiplexing, separation-and-quantification tool to measure protein adsorption to hydrophobic octyl sepharose (OS) adsorbent particles. Standard radiometric methods have also been used as a further check on the electrophoresis method mentioned above for purified-protein cases. Experimental results are interpreted in terms of an alternative kinetic model called volumetric interpretation of protein adsorption. A partitioning process between bulk solution and a three-dimensional interphase region that separates bulk solution from the physical adsorbent surface is the concept of the model. Protein molecules rapidly diffuse into an inflating interphase that is spontaneously formed by bringing a protein solution into contact with a physical surface, then follows by rearrangement of proteins within this interphase to achieve the maximum interphase concentration (dictated by energetics of interphase dehydration) within the thinnest (lowest volume) interphase possible. An important role of water in protein adsorption is emphasized and supported by this model. The fundamental aspects including the reversibility/irreversibility of protein adsorption, the multilayer adsorption, the applicability of thermodynamic/computational models, the capacity of protein adsorption, and the mechanism of so called Vroman effect are discussed and compared to the conventional theories. Superhydrophobic effect on the adsorption of human serum albumin is also examined.

  15. 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.

  16. Multi-scale Heat Kernel based Volumetric Morphology Signature

    PubMed Central

    Wang, Gang; Wang, Yalin

    2015-01-01

    Here we introduce a novel multi-scale heat kernel based regional shape statistical approach that may improve statistical power on the structural analysis. The mechanism of this analysis is driven by the graph spectrum and the heat kernel theory, to capture the volumetric geometry information in the constructed tetrahedral mesh. In order to capture profound volumetric changes, we first use the volumetric Laplace-Beltrami operator to determine the point pair correspondence between two boundary surfaces by computing the streamline in the tetrahedral mesh. Secondly, we propose a multi-scale volumetric morphology signature to describe the transition probability by random walk between the point pairs, which reflects the inherent geometric characteristics. Thirdly, a point distribution model is applied to reduce the dimensionality of the volumetric morphology signatures and generate the internal structure features. The multi-scale and physics based internal structure features may bring stronger statistical power than other traditional methods for volumetric morphology analysis. To validate our method, we apply support vector machine to classify synthetic data and brain MR images. In our experiments, the proposed work outperformed FreeSurfer thickness features in Alzheimer's disease patient and normal control subject classification analysis. PMID:26550613

  17. 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.

  18. Quantification of ultrasonic texture intra-heterogeneity via volumetric stochastic modeling for tissue characterization

    PubMed Central

    Al-Kadi, Omar S.; Chung, Daniel Y.F.; Carlisle, Robert C.; Coussios, Constantin C.; Noble, J. Alison

    2015-01-01

    Intensity variations in image texture can provide powerful quantitative information about physical properties of biological tissue. However, tissue patterns can vary according to the utilized imaging system and are intrinsically correlated to the scale of analysis. In the case of ultrasound, the Nakagami distribution is a general model of the ultrasonic backscattering envelope under various scattering conditions and densities where it can be employed for characterizing image texture, but the subtle intra-heterogeneities within a given mass are difficult to capture via this model as it works at a single spatial scale. This paper proposes a locally adaptive 3D multi-resolution Nakagami-based fractal feature descriptor that extends Nakagami-based texture analysis to accommodate subtle speckle spatial frequency tissue intensity variability in volumetric scans. Local textural fractal descriptors – which are invariant to affine intensity changes – are extracted from volumetric patches at different spatial resolutions from voxel lattice-based generated shape and scale Nakagami parameters. Using ultrasound radio-frequency datasets we found that after applying an adaptive fractal decomposition label transfer approach on top of the generated Nakagami voxels, tissue characterization results were superior to the state of art. Experimental results on real 3D ultrasonic pre-clinical and clinical datasets suggest that describing tumor intra-heterogeneity via this descriptor may facilitate improved prediction of therapy response and disease characterization. PMID:25595523

  19. 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

  20. 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.

  1. 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

  2. Cellular Stress Responses and Monitored Cellular Activities.

    PubMed

    Sawa, Teiji; Naito, Yoshifumi; Kato, Hideya; Amaya, Fumimasa

    2016-08-01

    To survive, organisms require mechanisms that enable them to sense changes in the outside environment, introduce necessary responses, and resist unfavorable distortion. Consequently, through evolutionary adaptation, cells have become equipped with the apparatus required to monitor their fundamental intracellular processes and the mechanisms needed to try to offset malfunction without receiving any direct signals from the outside environment. It has been shown recently that eukaryotic cells are equipped with a special mechanism that monitors their fundamental cellular functions and that some pathogenic proteobacteria can override this monitoring mechanism to cause harm. The monitored cellular activities involved in the stressed intracellular response have been researched extensively in Caenorhabditis elegans, where discovery of an association between key mitochondrial activities and innate immune responses was named "cellular associated detoxification and defenses (cSADD)." This cellular surveillance pathway (cSADD) oversees core cellular activities such as mitochondrial respiration and protein transport into mitochondria, detects xenobiotics and invading pathogens, and activates the endocrine pathways controlling behavior, detoxification, and immunity. The cSADD pathway is probably associated with cellular responses to stress in human inflammatory diseases. In the critical care field, the pathogenesis of lethal inflammatory syndromes (e.g., respiratory distress syndromes and sepsis) involves the disturbance of mitochondrial respiration leading to cell death. Up-to-date knowledge about monitored cellular activities and cSADD, especially focusing on mitochondrial involvement, can probably help fill a knowledge gap regarding the pathogenesis of lethal inflammatory syndromes in the critical care field. PMID:26954943

  3. 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.

  4. 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 ...

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Improved volumetric imaging in tomosynthesis using combined multiaxial sweeps.

    PubMed

    Gersh, Jacob A; Wiant, David B; Best, Ryan C M; Bennett, Marcus C; Munley, Michael T; King, June D; McKee, Mahta M; Baydush, Alan H

    2010-01-01

    This study explores the volumetric reconstruction fidelity attainable using tomosynthesis with a kV imaging system which has a unique ability to rotate isocentrically and with multiple degrees of mechanical freedom. More specifically, we seek to investigate volumetric reconstructions by combining multiple limited-angle rotational image acquisition sweeps. By comparing these reconstructed images with those of a CBCT reconstruction, we can gauge the volumetric fidelity of the reconstructions. In surgical situations, the described tomosynthesis-based system could provide high-quality volumetric imaging without requiring patient motion, even with rotational limitations present. Projections were acquired using the Digital Integrated Brachytherapy Unit, or IBU-D. A phantom was used which contained several spherical objects of varying contrast. Using image projections acquired during isocentric sweeps around the phantom, reconstructions were performed by filtered backprojection. For each image acquisition sweep configuration, a contrasting sphere is analyzed using two metrics and compared to a gold standard CBCT reconstruction. Since the intersection of a reconstructed sphere and an imaging plane is ideally a circle with an eccentricity of zero, the first metric presented compares the effective eccentricity of intersections of reconstructed volumes and imaging planes. As another metric of volumetric reconstruction fidelity, the volume of one of the contrasting spheres was determined using manual contouring. By comparing these manually delineated volumes with a CBCT reconstruction, we can gauge the volumetric fidelity of reconstructions. The configuration which yielded the highest overall volumetric reconstruction fidelity, as determined by effective eccentricities and volumetric contouring, consisted of two orthogonally-offset 60° L-arm sweeps and a single C-arm sweep which shared a pivot point with one the L-arm sweeps. When compared to a similar configuration that

  11. 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.

  12. 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.

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

    SciTech Connect

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

    2006-06-15

    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 deg.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

  14. 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

  15. Determination of volumetric concentration of solids in vertical pipeline hydrotransport

    NASA Astrophysics Data System (ADS)

    Zych, Marcin; Hanus, Robert; Petryka, Leszek; Strzępowicz, Anna; Zych, Piotr

    2016-03-01

    This paper presents an application of radioisotopes with reference to the determination of the solid phase volumetric concentration in a hydromixture by calibration of the measuring set. It shows how the gamma absorption equipment consisting of radioactive isotopes 241Am and scintillation probe, may be applied to the measurement of solid particles volumetric concentration in a flow. It is based on fact that the intensity of a gamma beam decreases as it passes through matter. In the described experiments as solid phase the ceramic models representing natural polymetallic ocean nodules were used. The especially constructed calibration stand and obtained relation between the related intensity of radiation and mean volumetric concentration of the solid phase are presented.

  16. Automated segmentation and shape characterization of volumetric data.

    PubMed

    Galinsky, Vitaly L; Frank, Lawrence R

    2014-05-15

    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

  17. Volumetric (3D) compressive sensing spectral domain optical coherence tomography

    PubMed Central

    Xu, Daguang; Huang, Yong; Kang, Jin U.

    2014-01-01

    In this work, we proposed a novel three-dimensional compressive sensing (CS) approach for spectral domain optical coherence tomography (SD OCT) volumetric image acquisition and reconstruction. Instead of taking a spectral volume whose size is the same as that of the volumetric image, our method uses a sub set of the original spectral volume that is under-sampled in all three dimensions, which reduces the amount of spectral measurements to less than 20% of that required by the Shan-non/Nyquist theory. The 3D image is recovered from the under-sampled spectral data dimension-by-dimension using the proposed three-step CS reconstruction strategy. Experimental results show that our method can significantly reduce the sampling rate required for a volumetric SD OCT image while preserving the image quality. PMID:25426320

  18. 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

  19. 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.

  20. 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.

  1. Volumetric measurements of a spatially growing dust acoustic wave

    SciTech Connect

    Williams, Jeremiah D.

    2012-11-15

    In this study, tomographic particle image velocimetry (tomo-PIV) techniques are used to make volumetric measurements of the dust acoustic wave (DAW) in a weakly coupled dusty plasma system in an argon, dc glow discharge plasma. These tomo-PIV measurements provide the first instantaneous volumetric measurement of a naturally occurring propagating DAW. These measurements reveal over the measured volume that the measured wave mode propagates in all three spatial dimensional and exhibits the same spatial growth rate and wavelength in each spatial direction.

  2. 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

  3. 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

  4. 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

  5. Compton coincidence volumetric imaging: a new x-ray volumetric imaging modality based on Compton scattering

    NASA Astrophysics Data System (ADS)

    Xu, Xiaochao

    2014-03-01

    Compton scattering is a dominant interaction during radiography and computed tomography x-ray imaging. However, the scattered photons are not used for extracting imaging information, but seriously degrade image quality. Here we introduce a new scheme that overcomes most of the problems associated with existing Compton scattering imaging schemes and allows Compton scattered photons to be effectively used for imaging. In our scheme, referred as Compton coincidence volumetric imaging (CCVI), a collimated monoenergetic x-ray beam is directed onto a thin semiconductor detector. A small portion of the photons is Compton scattered by the detector and their energy loss is detected. Some of the scattered photons intersect the imaging object, where they are Compton scattered a second time. The finally scattered photons are recorded by an areal energy resolving detector panel around the object. The two detectors work in coincidence mode. CCVI images the spatial electron density distribution in the imaging object. Similar to PET imaging, the event location can be located within a curve; therefore the imaging reconstruction algorithms are also similar to those of PET. Two statistical iterative imaging reconstruction algorithms are tested. Our study verifies the feasibility of CCVI in imaging acquisition and reconstruction. Various aspects of CCVI are discussed. If successfully implemented, it will offer a great potential for imaging dose reduction compared with x-ray CT. Furthermore, a CCVI modality will have no moving parts, which potentially offers cost reduction and faster imaging speed.

  6. 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.

  7. 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.

  8. Full-field pressure from snapshot and time-resolved volumetric PIV

    NASA Astrophysics Data System (ADS)

    Laskari, A.; de Kat, R.; Ganapathisubramani, B.

    2016-03-01

    This paper deals with pressure estimation from snapshot and time-resolved three-component (3C) volumetric PIV data using Taylor's hypothesis, an Eulerian and a pseudo-Lagrangian approach. The Taylor's hypothesis approach has been shown to provide accurate results for pressure in the case of 3C planar PIV data with an appropriate choice of convection velocity (de Kat and Ganapathisubramani 2013), and here we extend its use on 3C volumetric velocity snapshots. Application of the techniques to synthetic data shows that the Taylor's hypothesis approach performs best using the streamwise mean as the convection velocity and is affected the least by noise, while the Eulerian approach suffers the most. In terms of resolution, the pseudo-Lagrangian approach is the most sensitive. Its accuracy can be improved by increasing the frame time-separation when computing the material derivative, at the expense of volume loss from fluid parcels leaving the FOV. Comparison of the techniques on turbulent boundary layer data with DNS supports these observations and shows that the Taylor's hypothesis approach is the only way we can get pressure when time information is not present.

  9. 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.

  10. Obscuring Surface Anatomy in Volumetric Imaging Data

    PubMed Central

    Marcus, Daniel

    2012-01-01

    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. PMID:22968671

  11. Volumetric Video Motion Detection for Unobtrusive Human-Computer Interaction

    SciTech Connect

    SMALL, DANIEL E.; LUCK, JASON P.; CARLSON, JEFFREY J.

    2002-04-01

    The computer vision field has undergone a revolution of sorts in the past five years. Moore's law has driven real-time image processing from the domain of dedicated, expensive hardware, to the domain of commercial off-the-shelf computers. This thesis describes their work on the design, analysis and implementation of a Real-Time Shape from Silhouette Sensor (RT S{sup 3}). The system produces time-varying volumetric data at real-time rates (10-30Hz). The data is in the form of binary volumetric images. Until recently, using this technique in a real-time system was impractical due to the computational burden. In this thesis they review the previous work in the field, and derive the mathematics behind volumetric calibration, silhouette extraction, and shape-from-silhouette. For the sensor implementation, they use four color camera/framegrabber pairs and a single high-end Pentium III computer. The color cameras were configured to observe a common volume. This hardware uses the RT S{sup 3} software to track volumetric motion. Two types of shape-from-silhouette algorithms were implemented and their relative performance was compared. They have also explored an application of this sensor to markerless motion tracking. In his recent review of work done in motion tracking Gavrila states that results of markerless vision based 3D tracking are still limited. The method proposed in this paper not only expands upon the previous work but will also attempt to overcome these limitations.

  12. 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.

  13. 100KE/KW fuel storage basin surface volumetric factors

    SciTech Connect

    Conn, K.R.

    1996-01-01

    This Supporting Document presents calculations of surface Volumetric factors for the 100KE and 100KW Fuel Storage Basins. These factors relate water level changes to basin loss or additions of water, or the equivalent water displacement volumes of objects added to or removed from the basin.

  14. Gas migration modeling improves volumetric method of well control

    SciTech Connect

    Leach, C.P.; Quentin, K.M. )

    1994-12-26

    In the volumetric method, gas expansion during gas migration is allowed for by bleeding small quantities of fluid through the choke. When gas first reaches the choke, the influx is distributed near the surface in the annulus. Rapid gas migration then occurs, and mud and gas may need to be bled to maintain constant bottom hole pressure. The volumetric method is a technique for controlling gas kicks when circulation is not possible. The industry-recognized method is based on simple calculations which assume a single bubble of gas, the classic kick. This technique can now be evaluated by using more realistic, deterministic kick models. The results from such models cast double on some of the conventional procedures taught and used in the industry. This article details the analysis of influx behavior following a typical volumetric method. Numerical modeling of fluid losses as the surface pressure rises, gas migration, and dispersion are included to correspond accurately with field observations of kicks. Revised procedures are suggested to deal with these events better, such that the goals of the volumetric method are still attained.

  15. 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.

  16. 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.

  17. 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. PMID:26483557

  18. Cell biology of the future: Nanometer-scale cellular cartography

    PubMed Central

    2015-01-01

    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. PMID:26483557

  19. Two-dimensional reconstruction algorithm of an inverse-geometry volumetric CT system

    NASA Astrophysics Data System (ADS)

    Baek, Jongduk; Pelc, Norbert J.

    2007-03-01

    An inverse-geometry volumetric CT (IGCT) system uses a large source array opposite a smaller detector array. Conventional 2D IGCT reconstruction is performed by using gridding. We describe a 2D IGCT reconstruction algorithm without gridding. The IGCT raw data can be viewed as being composed of many fan beams, each with a detector at its focus. Each projection is undersampled but the missing samples are provided by other views. In order to get high spatial resolution, zeros are inserted between acquired projection samples in each fan beam, and reconstruction is performed using a direct fan beam reconstruction algorithm. Initial IGCT reconstruction results showed ringing artifacts caused by fact that the rho samples in the ensemble of views are not equally spaced. We present a new method for correcting the errors that reduces the artifacts to below one Hounsfield Unit

  20. 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.

  1. Note: Scanned multi-light-emitting-diode illumination for volumetric particle image velocimetry.

    PubMed

    Patterson, M D; Wettlaufer, J S

    2010-09-01

    We describe the development of both multilevel two-dimensional and grid-based three-dimensional illumination systems for volumetric particle image velocimetry (PIV) that uses a single camera and an arbitrary number of low powered lasers. This flexible system is robust and capable of capturing results over a range of spatiotemporal scales determined by the choice of camera, the depth of field of the lens, and the laser power. The system is demonstrated on a rotating spin-up experiment where we extract high fidelity velocity fields at up to 62 frames/s at a spatial resolution of 2352×1728 pixels. The flexibility and economy offered by this system--approximately one-tenth that of a comparable commercial package--may make it attractive to many laboratory users. PMID:20887007

  2. 3D imaging in volumetric scattering media using phase-space measurements.

    PubMed

    Liu, Hsiou-Yuan; Jonas, Eric; Tian, Lei; Zhong, Jingshan; Recht, Benjamin; Waller, Laura

    2015-06-01

    We demonstrate the use of phase-space imaging for 3D localization of multiple point sources inside scattering material. The effect of scattering is to spread angular (spatial frequency) information, which can be measured by phase space imaging. We derive a multi-slice forward model for homogenous volumetric scattering, then develop a reconstruction algorithm that exploits sparsity in order to further constrain the problem. By using 4D measurements for 3D reconstruction, the dimensionality mismatch provides significant robustness to multiple scattering, with either static or dynamic diffusers. Experimentally, our high-resolution 4D phase-space data is collected by a spectrogram setup, with results successfully recovering the 3D positions of multiple LEDs embedded in turbid scattering media. PMID:26072807

  3. Durga: A heuristically-optimized data collection strategy for volumetric magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Anand, Christopher Kumar; Curtis, Andrew Thomas; Kumar, Rakshit

    2008-02-01

    A heuristic design method for rapid volumetric magnetic resonance imaging data acquisition trajectories is presented, using a series of second-order cone optimization subproblems. Other researchers have considered non-raster data collection trajectories and under-sampled data patterns. This work demonstrates that much higher rates of under-sampling are possible with an asymmetric set of trajectories, with very little loss in resolution, but the addition of noise-like artefacts. The proposed data collection trajectory, Durga, further minimizes collection time by incorporating short un-refocused excitation pulses, resulting in above 98% collection efficiency for balanced steady state free precession imaging. The optimization subproblems are novel, in that they incorporate all requirements, including data collection (coverage), physicality (device limits), and signal generation (zeroth- and higher- moment properties) in a single convex problem, which allows the resulting trajectories to exhibit a higher collection efficiency than any existing trajectory design.

  4. 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.

  5. Novel volumetric 3D display based on point light source optical reconstruction using multi focal lens array

    NASA Astrophysics Data System (ADS)

    Lee, Jin su; Lee, Mu young; Kim, Jun oh; Kim, Cheol joong; Won, Yong Hyub

    2015-03-01

    Generally, volumetric 3D display panel produce volume-filling three dimensional images. This paper discusses a volumetric 3D display based on periodical point light sources(PLSs) construction using a multi focal lens array(MFLA). The voxel of discrete 3D images is formed in the air via construction of point light source emitted by multi focal lens array. This system consists of a parallel beam, a spatial light modulator(SLM), a lens array, and a polarizing filter. The multi focal lens array is made with UV adhesive polymer droplet control using a dispersing machine. The MFLA consists of 20x20 circular lens array. Each lens aperture of the MFLA shows 300um on average. The polarizing filter is placed after the SLM and the MFLA to set in phase mostly mode. By the point spread function, the PLSs of the system are located by the focal length of each lens of the MFLA. It can also provide the moving parallax and relatively high resolution. However it has a limit of viewing angle and crosstalk by a property of each lens. In our experiment, we present the letter `C', `O', `DE' and ball's surface with the different depth location. It could be seen clearly that when CCD camera is moved to its position following as transverse axis of the display system. From our result, we expect that varifocal lens like EWOD and LC-lens can be applied for real time volumetric 3D display system.

  6. High-power, red-emitting DBR-TPL for possible 3d holographic or volumetric displays

    NASA Astrophysics Data System (ADS)

    Feise, D.; Fiebig, C.; Blume, G.; Pohl, J.; Eppich, B.; Paschke, K.

    2013-03-01

    To create holographic or volumetric displays, it is highly desirable to move from conventional imaging projection displays, where the light is filtered from a constant source towards flying spot, where the correct amount of light is generated for every pixel. The only light sources available for such an approach, which requires visible, high output power with a spatial resolution beyond conventional lamps, are lasers. When adding the market demands for high electro-optical conversion efficiency, direct electrical modulation capability, compactness, reliability and massproduction compliance, this leaves only semiconductor diode lasers. We present red-emitting tapered diode lasers (TPL) emitting a powerful, visible, nearly diffraction limited beam (M²1/e² < 1.5) and a single longitudinal mode, which are well suited for 3d holographic and volumetric imaging. The TPLs achieved an optical output power in excess of 500 mW in the wavelength range between 633 nm and 638 nm. The simultaneous inclusion of a distributed Bragg reflector (DBR) surface grating provides wavelength selectivity and hence a spectral purity with a width Δλ < 5 pm. These properties allow dense spectral multiplexing to achieve output powers of several watts, which would be required for 3d volumetric display applications.

  7. 3D real holographic image movies are projected into a volumetric display using dynamic digital micromirror device (DMD) holograms.

    NASA Astrophysics Data System (ADS)

    Huebschman, Michael L.; Hunt, Jeremy; Garner, Harold R.

    2006-04-01

    The Texas Instruments Digital Micromirror Device (DMD) is being used as the recording medium for display of pre-calculated digital holograms. The high intensity throughput of the reflected laser light from DMD holograms enables volumetric display of projected real images as well as virtual images. A single DMD and single laser projector system has been designed to reconstruct projected images in a 6''x 6''x 4.5'' volumetric display. The volumetric display is composed of twenty-four, 6''-square, PSCT liquid crystal plates which are each cycled on and off to reduce unnecessary scatter in the volume. The DMD is an XGA format array, 1024x768, with 13.6 micron pitch mirrors. This holographic projection system has been used in the assessment of hologram image resolution, maximum image size, optical focusing of the real image, image look-around, and physiological depth cues. Dynamic movement images are projected by transferring the appropriately sequenced holograms to the DMD at movie frame rates.

  8. 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.

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

    PubMed

    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

  10. 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

  11. 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.

  12. 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.

  13. In-situ volumetric topography of IC chips for defect detection using infrared confocal measurement with active structured light

    NASA Astrophysics Data System (ADS)

    Chen, Liang-Chia; Le, Manh-Trung; Cong Phuc, Dao; Lin, Shyh-Tsong

    2014-09-01

    The article presents the development of in-situ integrated circuit (IC) chip defect detection techniques for automated clipping detection by proposing infrared imaging and full-field volumetric topography. IC chip inspection, especially held during or post IC packaging, has become an extremely critical procedure in IC fabrication to assure manufacturing quality and reduce production costs. To address this, in the article, microscopic infrared imaging using an electromagnetic light spectrum that ranges from 0.9 to 1.7 µm is developed to perform volumetric inspection of IC chips, in order to identify important defects such as silicon clipping, cracking or peeling. The main difficulty of infrared (IR) volumetric imaging lies in its poor image contrast, which makes it incapable of achieving reliable inspection, as infrared imaging is sensitive to temperature difference but insensitive to geometric variance of materials, resulting in difficulty detecting and quantifying defects precisely. To overcome this, 3D volumetric topography based on 3D infrared confocal measurement with active structured light, as well as light refractive matching principles, is developed to detect defects the size, shape and position of defects in ICs. The experimental results show that the algorithm is effective and suitable for in-situ defect detection of IC semiconductor packaging. The quality of defect detection, such as measurement repeatability and accuracy, is addressed. Confirmed by the experimental results, the depth measurement resolution can reach up to 0.3 µm, and the depth measurement uncertainty with one standard deviation was verified to be less than 1.0% of the full-scale depth-measuring range.

  14. Design and image quality results from volumetric CT with a flat-panel imager

    NASA Astrophysics Data System (ADS)

    Ross, William; Basu, Samit; Edic, Peter M.; Johnson, Mark; Pfoh, Armin H.; Rao, Ramakrishna; Ren, Baorui

    2001-06-01

    Preliminary MTF and LCD results obtained on several volumetric computed tomography (VCT) systems, employing amorphous flat panel technology, are presented. Constructed around 20-cm x 20-cm, 200-mm pitch amorphous silicon x-ray detectors, the prototypes use standard vascular or CT x-ray sources. Data were obtained from closed-gantry, benchtop and C-arm-based topologies, over a full 360 degrees of rotation about the target object. The field of view of the devices is approximately 15 cm, with a magnification of 1.25-1.5, providing isotropic resolution at isocenter of 133-160 mm. Acquisitions have been reconstructed using the FDK algorithm, modified by motion corrections also developed by GE. Image quality data were obtained using both industry standard and custom resolution phantoms as targets. Scanner output is compared on a projection and reconstruction basis against analogous output from a dedicated simulation package, also developed at GE. Measured MTF performance is indicative of a significant advance in isotropic image resolution over commercially available systems. LCD results have been obtained, using industry standard phantoms, spanning a contrast range of 0.3-1%. Both MTF and LCD measurements agree with simulated data.

  15. Volumetric velocity measurements on flows through heart valves

    NASA Astrophysics Data System (ADS)

    Troolin, Daniel; Amatya, Devesh; Longmire, Ellen

    2009-11-01

    Volumetric velocity fields inside two types of artificial heart valves were obtained experimentally through the use of volumetric 3-component velocimetry (V3V). Index matching was used to mitigate the effects of optical distortions due to interfaces between the fluid and curved walls. The steady flow downstream of a mechanical valve was measured and the results matched well with previously obtained 2D PIV results, such as those of Shipkowitz et al. (2002). Measurements upstream and downstream of a deformable silicone valve in a pulsatile flow were obtained and reveal significant three-dimensional features of the flow. Plots and movies will be shown, and a detailed discussion of the flow and various experimental considerations will be included. Reference: Shipkowitz, T, Ambrus J, Kurk J, Wickramasinghe K (2002) Evaluation technique for bileaflet mechanical valves. J. Heart Valve Disease. 11(2) pp. 275-282.

  16. Automated volumetric segmentation of retinal fluid on optical coherence tomography

    PubMed Central

    Wang, Jie; Zhang, Miao; Pechauer, Alex D.; Liu, Liang; Hwang, Thomas S.; Wilson, David J.; Li, Dengwang; Jia, Yali

    2016-01-01

    We propose a novel automated volumetric segmentation method to detect and quantify retinal fluid on optical coherence tomography (OCT). The fuzzy level set method was introduced for identifying the boundaries of fluid filled regions on B-scans (x and y-axes) and C-scans (z-axis). The boundaries identified from three types of scans were combined to generate a comprehensive volumetric segmentation of retinal fluid. Then, artefactual fluid regions were removed using morphological characteristics and by identifying vascular shadowing with OCT angiography obtained from the same scan. The accuracy of retinal fluid detection and quantification was evaluated on 10 eyes with diabetic macular edema. Automated segmentation had good agreement with manual segmentation qualitatively and quantitatively. The fluid map can be integrated with OCT angiogram for intuitive clinical evaluation. PMID:27446676

  17. A feasibility study of digital tomosynthesis for volumetric dental imaging

    NASA Astrophysics Data System (ADS)

    Cho, M. K.; Kim, H. K.; Youn, H.; Kim, S. S.

    2012-03-01

    We present a volumetric dental tomography method that compensates for insufficient projection views obtained from limited-angle scans. The reconstruction algorithm is based on the backprojection filtering method which employs apodizing filters that reduce out-of-plane blur artifacts and suppress high-frequency noise. In order to accompolish this volumetric imaging two volume-reconstructed datasets are synthesized. These individual datasets provide two different limited-angle scans performed at orthogonal angles. The obtained reconstructed images, using less than 15% of the number of projection views needed for a full skull phantom scan, demonstrate the potential use of the proposed method in dental imaging applications. This method enables a much smaller radiation dose for the patient compared to conventional dental tomography.

  18. CELLULAR MAGNESIUM HOMEOSTASIS

    PubMed Central

    Romani, Andrea M.P.

    2011-01-01

    Magnesium, the second most abundant cellular cation after potassium, is essential to regulate numerous cellular functions and enzymes, including ion channels, metabolic cycles, and signaling pathways, as attested by more than 1000 entries in the literature. Despite significant recent progress, however, our understanding of how cells regulate Mg2+ homeostasis and transport still remains incomplete. For example, the occurrence of major fluxes of Mg2+ in either direction across the plasma membrane of mammalian cells following metabolic or hormonal stimuli has been extensively documented. Yet, the mechanisms ultimately responsible for magnesium extrusion across the cell membrane have not been cloned. Even less is known about the regulation in cellular organelles. The present review is aimed at providing the reader with a comprehensive and up-to-date understanding of the mechanisms enacted by eukaryotic cells to regulate cellular Mg2+ homeostasis and how these mechanisms are altered under specific pathological conditions. PMID:21640700

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Accuracy of endodontic microleakage results: autoradiographic vs. volumetric measurements.

    PubMed

    Ximénez-Fyvie, L A; Ximénez-García, C; Carter-Bartlett, P M; Collado-Webber, F J

    1996-06-01

    The correlation between autoradiographic and volumetric leakage measurements was evaluated. Seventy-two anterior teeth with a single canal were selected and divided into three groups of 24. Group 1 served as control (no obturation), group 2 was obturated with gutta-percha only, and group 3 was obturated with gutta-percha and endodontic sealer. Samples were placed in a vertical position in 48-well cell culture plates and immersed in 1 ml of [14C]urea for 14 days. One-mm-thick horizontal serial sections were cut with a diamond disk cooled with liquid-nitrogen gas. Linear penetration was recorded by five independent evaluators from autoradiographs. Volumetric results were based on counts per minute registered in a liquid scintillation spectrometer. Pearson's correlation coefficient test was used to determine the lineal correlation between both methods of evaluation. No acceptable correlation values were found in any of the three groups (group 1, r = 0.34; group 2, r = 0.23; group 3, r = 0.20). Our results indicate that there is no correlation between linear and volumetric measurements of leakage. PMID:8934988

  5. 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.

  6. Non-Equilibrium Volumetric Response of Shocked Polymers

    NASA Astrophysics Data System (ADS)

    Clements, Brad

    2009-06-01

    Polymers are well known for their non-equilibrium deviatoric behavior. However, recent investigations involving both high rate shock experiments and equilibrium measured thermodynamic quantities have reminded us that the volumetric behavior also exhibits a non-equilibrium response. An area where this work should be important is the impact of glassy polymers. At the time of impact and near the impact surface, the polymer's volumetric response will be described as being Hugoniot-like, i.e., standard shock Hugoniot jump conditions apply. However, at later times, release waves from neighboring free surfaces will cause the polymer's volumetric response to be far from Hugoniot. In this talk, experiments showing the non-equilibrium behavior will be described. Following that discussion, a continuum-level theory is proposed that will allow us to bridge the equilibrium and non-equilibrium behaviors with a single model that can go seamlessly from one regime to the other.[4pt] In collaboration with Philip Rae and Dana Dattelbaum, Los Alamos National Laboratory.

  7. 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.

  8. Volumetric full-range magnetomotive optical coherence tomography

    PubMed Central

    Ahmad, Adeel; Kim, Jongsik; Shemonski, Nathan D.; Marjanovic, Marina; Boppart, Stephen A.

    2014-01-01

    Abstract. Magnetomotive optical coherence tomography (MM-OCT) can be utilized to spatially localize the presence of magnetic particles within tissues or organs. These magnetic particle-containing regions are detected by using the capability of OCT to measure small-scale displacements induced by the activation of an external electromagnet coil typically driven by a harmonic excitation signal. The constraints imposed by the scanning schemes employed and tissue viscoelastic properties limit the speed at which conventional MM-OCT data can be acquired. Realizing that electromagnet coils can be designed to exert MM force on relatively large tissue volumes (comparable or larger than typical OCT imaging fields of view), we show that an order-of-magnitude improvement in three-dimensional (3-D) MM-OCT imaging speed can be achieved by rapid acquisition of a volumetric scan during the activation of the coil. Furthermore, we show volumetric (3-D) MM-OCT imaging over a large imaging depth range by combining this volumetric scan scheme with full-range OCT. Results with tissue equivalent phantoms and a biological tissue are shown to demonstrate this technique. PMID:25472770

  9. High Resolution Dsm and Classified Volumetric Generation: AN Operational Approach to the Improvement of Geospatial Intelligence

    NASA Astrophysics Data System (ADS)

    Boccardo, P.; Gentili, G.

    2011-09-01

    As mentioned by Bacastow and Bellafiore, Geospatial Intelligence (GEOINT) is a field of knowledge, a process, and a profession. As knowledge, it is information integrated in a coherent space-time context that supports descriptions, explanations, or forecasts of human activities with which decision makers take action. As a process, it is the means by which data and information are collected, manipulated, geospatially reasoned, and disseminated to decision-makers. The geospatial intelligence professional establishes the scope of activities, interdisciplinary associations, competencies, and standards in academe, government, and the private sectors. Taking into account the fact that GEOINT is crucial for broad organizations, BLOM Group, a leading International provider within acquisition, processing and modeling of geographic information and ITHACA, a non-profit organization devoted to products and services delivering to the UN System in the field of geomatics, set up and provided GEOINT data to the main Italian companies operating in the field of mobile phone networking. This data, extremely useful for telecom network planning, have derived and produced using a standardized and effective (from the production point of view) approach. In this paper, all the procedures used for the production are described and tested with the aim to investigate the suitability of the data and the procedures themselves to any others possible fields of application.

  10. 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.

  11. Sub-diffraction Limit Localization of Proteins in Volumetric Space Using Bayesian Restoration of Fluorescence Images from Ultrathin Specimens

    PubMed Central

    Wang, Gordon; Smith, Stephen J.

    2012-01-01

    Photon diffraction limits the resolution of conventional light microscopy at the lateral focal plane to 0.61λ/NA (λ = wavelength of light, NA = numerical aperture of the objective) and at the axial plane to 1.4nλ/NA2 (n = refractive index of the imaging medium, 1.51 for oil immersion), which with visible wavelengths and a 1.4NA oil immersion objective is ∼220 nm and ∼600 nm in the lateral plane and axial plane respectively. This volumetric resolution is too large for the proper localization of protein clustering in subcellular structures. Here we combine the newly developed proteomic imaging technique, Array Tomography (AT), with its native 50–100 nm axial resolution achieved by physical sectioning of resin embedded tissue, and a 2D maximum likelihood deconvolution method, based on Bayes' rule, which significantly improves the resolution of protein puncta in the lateral plane to allow accurate and fast computational segmentation and analysis of labeled proteins. The physical sectioning of AT allows tissue specimens to be imaged at the physical optimum of modern high NA plan-apochormatic objectives. This translates to images that have little out of focus light, minimal aberrations and wave-front distortions. Thus, AT is able to provide images with truly invariant point spread functions (PSF), a property critical for accurate deconvolution. We show that AT with deconvolution increases the volumetric analytical fidelity of protein localization by significantly improving the modulation of high spatial frequencies up to and potentially beyond the spatial frequency cut-off of the objective. Moreover, we are able to achieve this improvement with no noticeable introduction of noise or artifacts and arrive at object segmentation and localization accuracies on par with image volumes captured using commercial implementations of super-resolution microscopes. PMID:22956902

  12. 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.

  13. Cellular Homeostasis and Aging.

    PubMed

    Hartl, F Ulrich

    2016-06-01

    Aging and longevity are controlled by a multiplicity of molecular and cellular signaling events that interface with environmental factors to maintain cellular homeostasis. Modulation of these pathways to extend life span, including insulin-like signaling and the response to dietary restriction, identified the cellular machineries and networks of protein homeostasis (proteostasis) and stress resistance pathways as critical players in the aging process. A decline of proteostasis capacity during aging leads to dysfunction of specific cell types and tissues, rendering the organism susceptible to a range of chronic diseases. This volume of the Annual Review of Biochemistry contains a set of two reviews addressing our current understanding of the molecular mechanisms underlying aging in model organisms and humans. PMID:27050288

  14. 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.

  15. 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. PMID:25291810

  16. A volumetric pulmonary CT segmentation method with applications in emphysema assessment

    NASA Astrophysics Data System (ADS)

    Silva, José Silvestre; Silva, Augusto; Santos, Beatriz S.

    2006-03-01

    A segmentation method is a mandatory pre-processing step in many automated or semi-automated analysis tasks such as region identification and densitometric analysis, or even for 3D visualization purposes. In this work we present a fully automated volumetric pulmonary segmentation algorithm based on intensity discrimination and morphologic procedures. Our method first identifies the trachea as well as primary bronchi and then the pulmonary region is identified by applying a threshold and morphologic operations. When both lungs are in contact, additional procedures are performed to obtain two separated lung volumes. To evaluate the performance of the method, we compared contours extracted from 3D lung surfaces with reference contours, using several figures of merit. Results show that the worst case generally occurs at the middle sections of high resolution CT exams, due the presence of aerial and vascular structures. Nevertheless, the average error is inferior to the average error associated with radiologist inter-observer variability, which suggests that our method produces lung contours similar to those drawn by radiologists. The information created by our segmentation algorithm is used by an identification and representation method in pulmonary emphysema that also classifies emphysema according to its severity degree. Two clinically proved thresholds are applied which identify regions with severe emphysema, and with highly severe emphysema. Based on this thresholding strategy, an application for volumetric emphysema assessment was developed offering new display paradigms concerning the visualization of classification results. This framework is easily extendable to accommodate other classifiers namely those related with texture based segmentation as it is often the case with interstitial diseases.

  17. 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

  18. 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.

  19. Statistical volumetric model for characterization and visualization of prostate cancer

    NASA Astrophysics Data System (ADS)

    Lu, Jianping; Srikanchana, Rujirutana; McClain, Maxine A.; Wang, Yue J.; Xuan, Jian Hua; Sesterhenn, Isabell A.; Freedman, Matthew T.; Mun, Seong K.

    2000-04-01

    To reveal the spatial pattern of localized prostate cancer distribution, a 3D statistical volumetric model, showing the probability map of prostate cancer distribution, together with the anatomical structure of the prostate, has been developed from 90 digitally-imaged surgical specimens. Through an enhanced virtual environment with various visualization modes, this master model permits for the first time an accurate characterization and understanding of prostate cancer distribution patterns. The construction of the statistical volumetric model is characterized by mapping all of the individual models onto a generic prostate site model, in which a self-organizing scheme is used to decompose a group of contours representing multifold tumors into localized tumor elements. Next crucial step of creating the master model is the development of an accurate multi- object and non-rigid registration/warping scheme incorporating various variations among these individual moles in true 3D. This is achieved with a multi-object based principle-axis alignment followed by an affine transform, and further fine-tuned by a thin-plate spline interpolation driven by the surface based deformable warping dynamics. Based on the accurately mapped tumor distribution, a standard finite normal mixture is used to model the cancer volumetric distribution statistics, whose parameters are estimated using both the K-means and expectation- maximization algorithms under the information theoretic criteria. Given the desired number of tissue samplings, the prostate needle biopsy site selection is optimized through a probabilistic self-organizing map thus achieving a maximum likelihood of cancer detection. We describe the details of our theory and methodology, and report our pilot results and evaluation of the effectiveness of the algorithm in characterizing prostate cancer distributions and optimizing needle biopsy techniques.

  20. 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.

  1. An intelligent, robust approach to volumetric aircraft sizing

    NASA Astrophysics Data System (ADS)

    Upton, Eric

    Advances in computational power have produced great strides in the later design and production portions of an aircraft's life cycle, and these advances have included the internal layout component of the design and manufacturing process. However, conceptual and preliminary design tools for internal layout remain primarily based on historical regressions and estimations---a situation that becomes untenable when considering revolutionary designs or component technologies. Bringing internal layout information forward in the design process can encourage the same level of benefits enjoyed by other disciplines as advances in aerodynamics, structures and other fields propagate forward in the design of complex systems. Accurate prediction of the volume required to contain all of an aircraft's internal components results in a more accurate prediction of aircraft specifications, mission effectiveness, and costs, helping determine if an aircraft is the best choice for continued development. This is not a computationally simple problem, however, and great care must be taken to ensure the efficiency of any proposed solution. Any solution must also address the uncertainty inherent in describing internal components early in the design process. Implementing a methodology that applies notions of an intelligent search for a solution, as well as deals robustly with component sizing, produces a high chance of success. Development of a robust, rapid method for assessing the volumetric characteristics of an aircraft in the context of the conceptual and preliminary design processes can offer many of the benefits of a complete internal layout without the immense assignment of resources typical in the detail phase of the design process. A simplified methodology for volumetrically sizing an aircraft is presented here as well as an assessment of the state-of-the-art techniques for volumetric considerations used in current aircraft design literature. A prototype tool using a combination of

  2. Plasmon enhanced photoacoustic generation from volumetric electromagnetic hotspots.

    PubMed

    Park, Sang-Gil; Yang, Seung-Bum; Ahn, Myeong-Su; Oh, Young-Jae; Kim, Yong Tae; Jeong, Ki-Hun

    2016-01-14

    This work reports plasmon enhanced photoacoustic generation by using a three dimensional plasmonic absorber. The 3D plasmonic absorber comprises a thin polymer film on glass nanopillar arrays with nanogap-rich silver nanoislands. The 3D plasmonic absorber clearly shows 24.6 times higher enhancement of photoacoustic signals at an excitation wavelength of 630 nm than a simple polymeric absorber. The photoacoustic enhancement results from the volumetric electromagnetic field enhancement on a light-absorbing polymer through 3D plasmonic nanostructures. This novel photoacoustic absorber provides a new direction for highly efficient ultrasonic generation. PMID:26659557

  3. 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.

  4. 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

  5. Progressive lossless compression of volumetric data using small memory load.

    PubMed

    Klajnsek, Gregor; Zalik, Borut

    2005-06-01

    Nowadays, applications dealing with volumetric datasets, Medical applications being a typical representative, have become possible even on low cost computers due to a rapid increase of computer memory and processing power. However, even today, dealing with volumetric datasets creates two considerable problems: slow visualization and large file sizes. While recently, due to significant progress in graphics hardware, real-time or near real-time volume visualization has become possible, volume compression still remains a problematic issue. This paper introduces a new method for lossless compression of volumetric datasets. It is based on quadtree encoding. The method consists of three steps: during initialization, so-called division quadtree is built. The smallest unit of the division quadtree is called basic macro-block. During the processing phase, Boolean intersection is built on pairs of quadtrees, and the differences are stored. In the last phase, the variable length encoding is applied to reduce the entropy among the differences. Proposed method supports progressive visualization, what is especially important when a transfer trough the internet is needed. To test the efficiency of this method it was compared to popular octree encoding scheme. The results proved that data coherence is exploited more sufficiently using proposed quadtree approach. Additional advantage of this approach is that the algorithm does not need a lot of memory space. Only two quadtrees of two consecutive slices need be loaded in the memory at the same time. This feature makes this algorithm extremely attractive for possible hardware implementation. This paper introduces a new method for the compression of volumetric datasets. It is based on quadtree encoding. This method consists of three steps: during initialization, a so-called division quadtree is built. The smallest, unit of the division quadtree is called a basic macro-block. A Boolean intersection is built on pairs of quadtrees during

  6. Cross-scale coefficient selection for volumetric medical image fusion.

    PubMed

    Shen, Rui; Cheng, Irene; Basu, Anup

    2013-04-01

    Joint analysis of medical data collected from different imaging modalities has become a common clinical practice. Therefore, image fusion techniques, which provide an efficient way of combining and enhancing information, have drawn increasing attention from the medical community. In this paper, we propose a novel cross-scale fusion rule for multiscale-decomposition-based fusion of volumetric medical images taking into account both intrascale and interscale consistencies. An optimal set of coefficients from the multiscale representations of the source images is determined by effective exploitation of neighborhood information. An efficient color fusion scheme is also proposed. Experiments demonstrate that our fusion rule generates better results than existing rules. PMID:22868528

  7. 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…

  8. Teaching cellular engineering.

    PubMed

    Hammer, Daniel A; Waugh, Richard E

    2006-02-01

    Cellular engineering is one of the fastest growing subdisciplines in the field of Biomedical Engineering. It involves the application of engineering analysis to understand and control cellular behavior, with the ultimate objective of developing novel therapeutic or diagnostic approaches for the clinic or harnessing cellular function for commercial applications. Well-educated students in this area need strong foundational knowledge in engineering science, chemistry, and cell and molecular biology. In undergraduate curricula, the challenge is to include essential engineering skills plus appropriate levels of training in chemistry and biology while satisfying accreditation-mandated breadth in engineering training. At the graduate level, educators must accommodate students with diverse backgrounds and provide them with both a state-of-the-art understanding of the life sciences and the most advanced engineering skills. Engineering curricular content should include mechanics and materials, physical chemistry, transport phenomena, and control theory. Training from faculty with appointments and research programs in the life sciences is generally recommended, and additional life science content should also be integrated within the engineering curriculum. A capstone course in cellular engineering that includes opportunities for students to have hands-on experiences with state-of-the-art laboratory techniques is highly recommended. PMID:16450196

  9. Auxin and Cellular Elongation.

    PubMed

    Velasquez, Silvia Melina; Barbez, Elke; Kleine-Vehn, Jürgen; Estevez, José M

    2016-03-01

    Auxin is a crucial growth regulator in plants. However, a comprehensive understanding of how auxin induces cell expansion is perplexing, because auxin acts in a concentration- and cell type-dependent manner. Consequently, it is desirable to focus on certain cell types to exemplify the underlying growth mechanisms. On the other hand, plant tissues display supracellular growth (beyond the level of single cells); hence, other cell types might compromise the growth of a certain tissue. Tip-growing cells do not display neighbor-induced growth constraints and, therefore, are a valuable source of information for growth-controlling mechanisms. Here, we focus on auxin-induced cellular elongation in root hairs, exposing a mechanistic view of plant growth regulation. We highlight a complex interplay between auxin metabolism and transport, steering root hair development in response to internal and external triggers. Auxin signaling modules and downstream cascades of transcription factors define a developmental program that appears rate limiting for cellular growth. With this knowledge in mind, the root hair cell is a very suitable model system in which to dissect cellular effectors required for cellular expansion. PMID:26787325

  10. 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)

  11. 47 CFR 22.972 - Interference resolution procedures.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... PUBLIC MOBILE SERVICES Cellular Radiotelephone Service § 22.972 Interference resolution procedures. (a... safety/CII signal; (ii) Decreasing the power of the part 90 ESMR and/or Cellular Radiotelephone system signal; (iii) Modifying the part 90 ESMR and/or Cellular Radiotelephone system antenna height;...

  12. 47 CFR 22.972 - Interference resolution procedures.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... PUBLIC MOBILE SERVICES Cellular Radiotelephone Service § 22.972 Interference resolution procedures. (a... signal; (iii) Modifying the part 90 ESMR and/or Cellular Radiotelephone system antenna height; (iv) Modifying the part 90 ESMR and/or Cellular Radiotelephone system antenna characteristics; (v)...

  13. 47 CFR 22.972 - Interference resolution procedures.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... PUBLIC MOBILE SERVICES Cellular Radiotelephone Service § 22.972 Interference resolution procedures. (a... signal; (iii) Modifying the part 90 ESMR and/or Cellular Radiotelephone system antenna height; (iv) Modifying the part 90 ESMR and/or Cellular Radiotelephone system antenna characteristics; (v)...

  14. 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

  15. [Dispute Resolutions].

    ERIC Educational Resources Information Center

    Hale, Claudia L.; Cooks, Leda M.

    1994-01-01

    Focusing on the teaching of alternative dispute resolutions at universities, Claudia L. Hale and Leda M. Cooks argue that mediation should be taught primarily as a communication process that involves the joint efforts of mediator and disputants. Teachers of mediation should begin by distinguishing mediation from other forms of dispute resolution,…

  16. Volumetrics of CO2 storage in deep saline formations.

    PubMed

    Steele-MacInnis, Matthew; Capobianco, Ryan M; Dilmore, Robert; Goodman, Angela; Guthrie, George; Rimstidt, J Donald; Bodnar, Robert J

    2013-01-01

    Concern about the role of greenhouse gases in global climate change has generated interest in sequestering CO(2) from fossil-fuel combustion in deep saline formations. Pore space in these formations is initially filled with brine, and space to accommodate injected CO(2) must be generated by displacing brine, and to a lesser extent by compression of brine and rock. The formation volume required to store a given mass of CO(2) depends on the storage mechanism. We compare the equilibrium volumetric requirements of three end-member processes: CO(2) stored as a supercritical fluid (structural or stratigraphic trapping); CO(2) dissolved in pre-existing brine (solubility trapping); and CO(2) solubility enhanced by dissolution of calcite. For typical storage conditions, storing CO(2) by solubility trapping reduces the volume required to store the same amount of CO(2) by structural or stratigraphic trapping by about 50%. Accessibility of CO(2) to brine determines which storage mechanism (structural/stratigraphic versus solubility) dominates at a given time, which is a critical factor in evaluating CO(2) volumetric requirements and long-term storage security. PMID:22916959

  17. Analytic Intermodel Consistent Modeling of Volumetric Human Lung Dynamics.

    PubMed

    Ilegbusi, Olusegun; Seyfi, Behnaz; Neylon, John; Santhanam, Anand P

    2015-10-01

    Human lung undergoes breathing-induced deformation in the form of inhalation and exhalation. Modeling the dynamics is numerically complicated by the lack of information on lung elastic behavior and fluid-structure interactions between air and the tissue. A mathematical method is developed to integrate deformation results from a deformable image registration (DIR) and physics-based modeling approaches in order to represent consistent volumetric lung dynamics. The computational fluid dynamics (CFD) simulation assumes the lung is a poro-elastic medium with spatially distributed elastic property. Simulation is performed on a 3D lung geometry reconstructed from four-dimensional computed tomography (4DCT) dataset of a human subject. The heterogeneous Young's modulus (YM) is estimated from a linear elastic deformation model with the same lung geometry and 4D lung DIR. The deformation obtained from the CFD is then coupled with the displacement obtained from the 4D lung DIR by means of the Tikhonov regularization (TR) algorithm. The numerical results include 4DCT registration, CFD, and optimal displacement data which collectively provide consistent estimate of the volumetric lung dynamics. The fusion method is validated by comparing the optimal displacement with the results obtained from the 4DCT registration. PMID:26292034

  18. Spatio-volumetric hazard estimation in the Auckland volcanic field

    NASA Astrophysics Data System (ADS)

    Bebbington, Mark S.

    2015-05-01

    The idea of a volcanic field `boundary' is prevalent in the literature, but ill-defined at best. We use the elliptically constrained vents in the Auckland Volcanic Field to examine how spatial intensity models can be tested to assess whether they are consistent with such features. A means of modifying the anisotropic Gaussian kernel density estimate to reflect the existence of a `hard' boundary is then suggested, and the result shown to reproduce the observed elliptical distribution. A new idea, that of a spatio-volumetric model, is introduced as being more relevant to hazard in a monogenetic volcanic field than the spatiotemporal hazard model due to the low temporal rates in volcanic fields. Significant dependencies between the locations and erupted volumes of the observed centres are deduced, and expressed in the form of a spatially-varying probability density. In the future, larger volumes are to be expected in the `gaps' between existing centres, with the location of the greatest forecast volume lying in the shipping channel between Rangitoto and Castor Bay. The results argue for tectonic control over location and magmatic control over erupted volume. The spatio-volumetric model is consistent with the hypothesis of a flat elliptical area in the mantle where tensional stresses, related to the local tectonics and geology, allow decompressional melting.

  19. High volumetric capacitance near the insulator-metal percolation transition

    NASA Astrophysics Data System (ADS)

    Efros, A. L.

    2011-10-01

    I propose a new type of capacitor with a very high volumetric capacitance. It is based on the known phenomenon of the sharp increase of the dielectric constant of a metal-insulator composite in the vicinity of the percolation threshold on the insulator side. The optimization suggests that the sizes of the metallic particles should fall within the nanoscale. The distance between planar electrodes should be somewhat larger than the correlation length of the percolation theory and ≈10-20 times larger than the size of the particles while the area of the electrodes could be unlimited. The random electric field in the capacitor is calculated and is shown to be larger than the average field corresponding to the potential difference of the electrodes. This random field is potentially responsible for the dielectric breakdown. The estimated breakdown voltage of the capacitor shows that the stored energy density might be significantly larger than that of electrolytic capacitors while the volumetric capacitances might be comparable. The charging and discharging times should be significantly smaller than the corresponding times of batteries and even electrolytic capacitors.

  20. Interactive visualization of solar mass ejection imager (SMEI) volumetric data

    NASA Astrophysics Data System (ADS)

    Yu, Yang; Hick, P. P.; Jackson, Bernard V.

    2005-08-01

    We present a volume rendering system developed for the real time visualization and manipulation of 3D heliospheric volumetric solar wind density and velocity data obtained from the Solar Mass Ejection Imager (SMEI) and interplanetary scintillation (IPS) velocities over the same time period. Our system exploits the capabilities of the VolumePro 1000 board from TeraRecon, Inc., a low-cost 64-bit PCI board capable of rendering up to a 512-cubed array of volume data in real time at up to 30 frames per second on a standard PC. Many volume-rendering operations have been implemented with this system such as stereo/perspective views, animations of time-sequences, and determination of coronal mass ejection (CME) volumes and masses. In these visualizations we highlight one time period where a halo CMEs was observed by SMEI to engulf Earth on October 29, 2003. We demonstrate how this system is used to measure the distribution of structure and provide 3D mass for individual CME features, including the ejecta associated with the large prominence viewed moving to the south of Earth following the late October CME. Comparisons with the IPS velocity volumetric data give pixel by pixel and total kinetic energies for these events.

  1. 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.

  2. 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

  3. 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%. PMID:23851472

  4. Left-ventricular boundary detection from spatiotemporal volumetric CT images

    NASA Astrophysics Data System (ADS)

    Tu, Hsiao-Kun; Matheny, Art; Goldgof, Dmitry B.

    1993-07-01

    This paper presents a new technique for LV boundary detection from 3-D volumetric cardiac images. The proposed method consists of boundary detection and boundary refinement stages. In the boundary detection stage, a spatio-temporal (4-D) gradient operator is used to capture the temporal gradients of dynamic LV boundaries and to smooth time uncorrelated noise. Spatio-temporal edge detection is performed outward from an approximate center of the left ventricle. In the boundary refinement stage, spherical harmonic model is fitted to the detected boundaries. Based on this model, false boundaries are removed; LV boundaries are recovered. A left ventricle is a bright, smooth region, varying in size over the heart cycle. This a priori knowledge is incorporated in detection and refinement of LV boundaries to reduce the effect of noise. The intensity of the inner (close to the center) neighbors of the LV boundary is brighter than the outer. The size of the left ventricle is used in boundary refinement to select proper boundaries to be fitted by the spherical harmonic mode. We demonstrate the advantages of 4-D edge detection over 3-D and the use of spherical harmonics to refine LV boundaries. Our experimental data is supplied by Dr. Eric Hoffman at University of Pennsylvania medical school and consists of 16 volumetric (128 by 128 by 118) CT images taken through a heart cycle.

  5. 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.

  6. Three-dimensional volumetric display in rubidium vapor

    NASA Astrophysics Data System (ADS)

    Kim, Isaac I.; Korevaar, Eric J.; Hakakha, Harel

    1996-03-01

    The successful demonstration of a novel 3D volumetric display based on the intersection of two low power diode laser beams in an atomic vapor is presented. A 780 nm laser and a 630 nm laser are directed via mirrors and x-y scanners towards an enclosure containing rubidium vapor, where they intersect at 90 degrees. Rubidium atoms within the small intersection volume undergo 5s1/2 to 5p3/2 excitation from the 780 nm laser, and then 5p3/2 to 6d5/2 excitation from the 630 nm laser, resulting in red omnidirectional fluorescence from the intersection point. Tuning of the lasers to the exact excitation wavelengths resulted in an extended red spot with maximum brightness. By tuning the lasers slightly off the transition wavelengths, a very localized red spot with slightly less brightness was produced. A series of intersection points were scanned in a time less than the eye's 15 Hz refresh rate to create true 3D volumetric images such as a floating cube and rotating globe, which were viewable from many angles. The maximum speed of the mechanical scanners limited the complexity of the 3D images. By incorporating higher power lasers and faster acousto-optical scanners, this technique could allow the 3D viewing of real time air traffic control, medical images, or theater battlefield management.

  7. Fabrication of cellular materials

    NASA Astrophysics Data System (ADS)

    Prud'homme, Robert K.; Aksay, Ilhan A.; Garg, Rajeev

    1996-02-01

    Nature uses cellular materials in applications requiring strength while, simultaneously, minimizing raw materials requirements. Minimizing raw materials is efficient both in terms of the energy expended by the organism to synthesize the structure and in terms of the strength- to-weight ratio of the structure. Wood is the most obvious example of cellular bio-materials, and it is the focus of other presentations in this symposium. The lightweight bone structure of birds is another excellent example where weight is a key criterion. The anchoring foot of the common muscle [Mytilus edulis] whereby it attaches itself to objects is a further example of a biological system that uses a foam to fill space and yet conserve on raw materials. In the case of the muscle the foam is water filled and the foot structure distributes stress over a larger area so that the strength of the byssal thread from which it is suspended is matched to the strength of interfacial attachment of the foot to a substrate. In these examples the synthesis and fabrication of the cellular material is directed by intercellular, genetically coded, biochemical reactions. The resulting cell sizes are microns in scale. Cellular materials at the next larger scale are created by organisms at the next higher level of integration. For example an African tree frog lays her eggs in a gas/fluid foam sack she builds on a branch overhanging a pond. The outside of the foam sack hardens in the sun and prevents water evaporation. The foam structure minimizes the amount of fluid that needs to be incorporated into the sack and minimizes its weight. However, as far as the developing eggs are concerned, they are in an aqueous medium, i.e. the continuous fluid phase of the foam. After precisely six days the eggs hatch, and the solidified outer wall re-liquefies and dumps the emerging tadpoles into the pond below. The bee honeycomb is an example of a cellular material with exquisite periodicity at millimeter length scales. The

  8. Cellular growth in biofilms

    SciTech Connect

    Wood, B.D.; Whitaker, S.

    1999-09-20

    In this paper the authors develop a macroscopic evolutionary equation for the growth of the cellular phase starting from a microscopic description of mass transport and a simple structured model for product formation. The methods of continuum mechanics and volume averaging are used to develop the macroscopic representation by carefully considering the fluxes of chemical species that pertain to cell growth. The concept of structured models is extended to include the transport of reacting chemical species at the microscopic scale. The resulting macroscopic growth model is similar in form to previously published models for the transport of a single substrate and electron donor and for the production of cellular mass and exopolymer. The method of volume averaging indicated under what conditions the developed growth model is valid and provides an explicit connection between the relevant microscopic model parameters and their corresponding macroscopic counterparts.

  9. Cellular dysfunction in sepsis.

    PubMed

    Singer, Mervyn

    2008-12-01

    Cellular dysfunction is a commonplace sequelum of sepsis and other systemic inflammatory conditions. Impaired energy production (related to mitochondrial inhibition, damage, and reduced protein turnover) appears to be a core mechanism underlying the development of organ dysfunction. The reduction in energy availability appears to trigger a metabolic shutdown that impairs normal functioning of the cell. This may well represent an adaptive mechanism analogous to hibernation that prevents a massive degree of cell death and thus enables eventual recovery in survivors. PMID:18954700

  10. Radiolabeled cellular blood elements

    SciTech Connect

    Thakur, M.L.; Ezikowitz, M.D.; Hardeman, M.R.

    1985-01-01

    This book contains papers delivered by guest lectures and participants at the Advanced Study Institute's colloquium on Radiolabeled Cellular Blood Elements at Maratea, Italy on August 29, to September 9, 1982. The book includes chapters on basic cell physiology and critical reviews of data and experience in the preparation and use of radiolabeled cells, as well as reports on very recent developments, from a faculty that included experts on cell physiology in health and disease and on the technology of in vivo labeling.

  11. 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. PMID:25271778

  12. 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. PMID:24999557

  13. Quantum cellular automata

    NASA Astrophysics Data System (ADS)

    Porod, Wolfgang; Lent, Craig S.; Bernstein, Gary H.

    1994-06-01

    The Notre Dame group has developed a new paradigm for ultra-dense and ultra-fast information processing in nanoelectronic systems. These Quantum Cellular Automata (QCA's) are the first concrete proposal for a technology based on arrays of coupled quantum dots. The basic building block of these cellular arrays is the Notre Dame Logic Cell, as it has been called in the literature. The phenomenon of Coulomb exclusion, which is a synergistic interplay of quantum confinement and Coulomb interaction, leads to a bistable behavior of each cell which makes possible their use in large-scale cellular arrays. The physical interaction between neighboring cells has been exploited to implement logic functions. New functionality may be achieved in this fashion, and the Notre Dame group invented a versatile majority logic gate. In a series of papers, the feasibility of QCA wires, wire crossing, inverters, and Boolean logic gates was demonstrated. A major finding is that all logic functions may be integrated in a hierarchial fashion which allows the design of complicated QCA structures. The most complicated system which was simulated to date is a one-bit full adder consisting of some 200 cells. In addition to exploring these new concepts, efforts are under way to physically realize such structures both in semiconductor and metal systems. Extensive modeling work of semiconductor quantum dot structures has helped identify optimum design parameters for QCA experimental implementations.

  14. 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

  15. Performance of a volumetric CT scanner based upon a flat-panel imager

    NASA Astrophysics Data System (ADS)

    Jaffray, David A.; Siewerdsen, Jeffrey H.; Drake, Douglas G.

    1999-05-01

    To characterize the performance of a cone-beam computed tomography (CBCT) imaging system based upon an indirect- detection, amorphous silicon flat-panel imager (FPI). Tomographic images obtained using the FPI are presented, and the signal and noise characteristics of reconstructed images are quantified. Specifically, the spatial uniformity, CT linearity, contrast performance, noise characteristics, spatial resolution, and soft-tissue visualization are examined. Finally, the performance of the FPI-based CT system is discussed in relation to existing clinical technologies. A table-top measurements system was constructed to allow investigation of FPI performance in CBCT within a precisely controlled and reproducible geometry. The FPI incorporates a 512 X 512 active matrix array of a-Si:H thin-film transistors and photodiodes in combination with an overlying (133 mg/cm2 Gd2O2S:Tb) phosphor. The commercially available prototype FPI has a pixel pitch of 400 micrometer, a fill factor of approximately 80%, can be read at a maximum frame rate of 5 fps, and provides 16 bit digitization. Mounted upon an optical bench are the x-ray tube (in a rigid support frame), the object to be imaged (upon a precision rotation/translation table), and the FPI (mounted upon a precision translation table). The entire setup is directed under computer control, and volumetric imaging is accomplished by rotating the object incrementally over 360 degrees, delivering a radiographic x-ray pulse (e.g., 100 - 130 kVp, approximately 0.1 - 10 mAs), and acquiring a projection image at each increment. Prior to reconstruction, dark and flood- field corrections are applied to account for stationary nonuniformities in detector response and dark current. Tomographic images are reconstructed from the projections using the Feldkamp filtered back-projection algorithm for CBCT. The linearity of the CBCT system was compared to that of a commercial scanner (Philips SR-7000) using materials ranging in CT number from

  16. 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. PMID:22291153

  17. Volumetric neuroimage analysis extensions for the MIPAV software package.

    PubMed

    Bazin, Pierre-Louis; Cuzzocreo, Jennifer L; Yassa, Michael A; Gandler, William; McAuliffe, Matthew J; Bassett, Susan S; Pham, Dzung L

    2007-09-15

    We describe a new collection of publicly available software tools for performing quantitative neuroimage analysis. The tools perform semi-automatic brain extraction, tissue classification, Talairach alignment, and atlas-based measurements within a user-friendly graphical environment. They are implemented as plug-ins for MIPAV, a freely available medical image processing software package from the National Institutes of Health. Because the plug-ins and MIPAV are implemented in Java, both can be utilized on nearly any operating system platform. In addition to the software plug-ins, we have also released a digital version of the Talairach atlas that can be used to perform regional volumetric analyses. Several studies are conducted applying the new tools to simulated and real neuroimaging data sets. PMID:17604116

  18. Thermal stresses from large volumetric expansion during freezing of biomaterials.

    PubMed

    Shi, X; Datta, A K; Mukherjee, Y

    1998-12-01

    Thermal stresses were studied in freezing of biomaterials containing significant amounts of water. An apparent specific heat formulation of the energy equation and a viscoelastic model for the mechanics problem were used to analyze the transient axi-symmetric freezing of a long cylinder. Viscoelastic properties were measured in an Instron machine. Results show that, before phase change occurs at any location, both radial and circumferential stresses are tensile and keep increasing until phase change begins. The maximum principal tensile stress during phase change increases with a decrease in boundary temperature (faster cooling). This is consistent with experimentally observed fractures at a lower boundary temperature. Large volumetric expansion during water to ice transformation was shown to be the primary contributor to large stress development. For very rapid freezing, relaxation may not be significant, and an elastic model may be sufficient. PMID:10412455

  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.

    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. PMID:25735291

  1. 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

  2. Evaluation of Automated Volumetric Cartilage Quantification for Hip Preservation Surgery.

    PubMed

    Ramme, Austin J; Guss, Michael S; Vira, Shaleen; Vigdorchik, Jonathan M; Newe, Axel; Raithel, Esther; Chang, Gregory

    2016-01-01

    Automating the process of femoroacetabular cartilage identification from magnetic resonance imaging (MRI) images has important implications to guiding clinical care by providing a temporal metric that allows for optimizing the timing for joint preservation surgery. In this paper, we evaluate a new automated cartilage segmentation method using a time trial, segmented volume comparison, overlap metrics, and Euclidean distance mapping. We report interrater overlap metrics using the true fast imaging with steady-state precession MRI sequence of 0.874, 0.546, and 0.704 for the total overlap, union overlap, and mean overlap, respectively. This method was 3.28× faster than manual segmentation. This technique provides clinicians with volumetric cartilage information that is useful for optimizing the timing for joint preservation procedures. PMID:26377376

  3. [Electronic portal image device dosimetry for volumetric modulated arc therapy].

    PubMed

    Tatsumi, Daisaku; Nakada, Ryosei; Ienaga, Akinori; Yomoda, Akane; Inoue, Makoto; Ichida, Takao; Hosono, Masako

    2013-01-01

    Recently electronic portal image devices (EPIDs) have been widely used for quality assurance and dose verification. However there are no reports describing EPID dosimetry for Elekta volumetric modulated arc therapy (VMAT). We have investigated EPID dosimetry during VMAT delivery using a commercial software EPIDose with an Elekta Synergy linac. Dose rate dependence and the linac system sag during gantry rotation were measured. Gamma indices were calculated between measured doses using an EPID and calculation made by a treatment planning system for prostate VMAT test plans. The results were also compared to gamma indices using films and a two-dimensional detector array, MapCHECK2. The pass rates of the gamma analysis with a criterion of 3% and 2 mm for the three methods were over 96% with good consistency. Our results have showed that EPID dosimetry is feasible for Elekta VMAT. PMID:23358333

  4. In-line hologram segmentation for volumetric samples.

    PubMed

    Orzó, László; Göröcs, Zoltán; Fehér, András; Tőkés, Szabolcs

    2013-01-01

    We propose a fast, noniterative method to segment an in-line hologram of a volumetric sample into in-line subholograms according to its constituent objects. In contrast to the phase retrieval or twin image elimination algorithms, we do not aim or require to reconstruct the complex wave field of all the objects, which would be a more complex task, but only provide a good estimate about the contribution of the particular objects to the original hologram quickly. The introduced hologram segmentation algorithm exploits the special inner structure of the in-line holograms and applies only the estimated supports and reconstruction distances of the corresponding objects as parameters. The performance of the proposed method is demonstrated and analyzed experimentally both on synthetic and measured holograms. We discussed how the proposed algorithm can be efficiently applied for object reconstruction and phase retrieval tasks. PMID:23292422

  5. Volumetric and selective heating in agriculture and chemistry applications

    NASA Astrophysics Data System (ADS)

    Raghavan, Vijaya G.; Dai, Jianming; Sunjka, Predrag S.

    2004-04-01

    Microwaves of 2450 MHz have been attracting attention from researchers of various fields. The most distinguished characteristics of microwave from conventional heating are volumetric and selectivity. Due to these characteristics, when combined with convective air, microwave-assisted drying can greatly reduce drying time and energy usage to achieve certain moisture content. These characteristics also make it possible to combine this highly efficient heating method with vacuum drying by passing the energy through a microwave-transparent vacuum chamber. Microwaves also have various applications in chemistry such as extraction of natural products from plant materials and microwave-assisted synthesis. In this paper, the work conducted in our lab on the applications of microwave energy in agriculture and chemistry is briefly reviewed.

  6. Adaptive and Quality Quadrilateral/Hexahedral Meshing from Volumetric Data⋆

    PubMed Central

    Zhang, Yongjie; Bajaj, Chandrajit

    2009-01-01

    This paper describes an algorithm to extract adaptive and quality quadrilateral/hexahedral meshes directly from volumetric data. First, a bottom-up surface topology preserving octree-based algorithm is applied to select a starting octree level. Then the dual contouring method is used to extract a preliminary uniform quad/hex mesh, which is decomposed into finer quads/hexes adaptively without introducing any hanging nodes. The positions of all boundary vertices are recalculated to approximate the boundary surface more accurately. Mesh adaptivity can be controlled by a feature sensitive error function, the regions that users are interested in, or finite element calculation results. Finally, a relaxation based technique is deployed to improve mesh quality. Several demonstration examples are provided from a wide variety of application domains. Some extracted meshes have been extensively used in finite element simulations. PMID:19750180

  7. Volumetric capnography: lessons from the past and current clinical applications.

    PubMed

    Verscheure, Sara; Massion, Paul B; Verschuren, Franck; Damas, Pierre; Magder, Sheldon

    2016-01-01

    Dead space is an important component of ventilation-perfusion abnormalities. Measurement of dead space has diagnostic, prognostic and therapeutic applications. In the intensive care unit (ICU) dead space measurement can be used to guide therapy for patients with acute respiratory distress syndrome (ARDS); in the emergency department it can guide thrombolytic therapy for pulmonary embolism; in peri-operative patients it can indicate the success of recruitment maneuvers. A newly available technique called volumetric capnography (Vcap) allows measurement of physiological and alveolar dead space on a regular basis at the bedside. We discuss the components of dead space, explain important differences between the Bohr and Enghoff approaches, discuss the clinical significance of arterial to end-tidal CO2 gradient and finally summarize potential clinical indications for Vcap measurements in the emergency room, operating room and ICU. PMID:27334879

  8. Occlusion-capable multiview volumetric three-dimensional display

    NASA Astrophysics Data System (ADS)

    Cossairt, Oliver S.; Napoli, Joshua; Hill, Samuel L.; Dorval, Rick K.; Favalora, Gregg E.

    2007-03-01

    Volumetric 3D displays are frequently purported to lack the ability to reconstruct scenes with viewer-position-dependent effects such as occlusion. To counter these claims, a swept-screen 198-view horizontal-parallax-only 3D display is reported here that is capable of viewer-position-dependent effects. A digital projector illuminates a rotating vertical diffuser with a series of multiperspective 768×768 pixel renderings of a 3D scene. Evidence of near-far object occlusion is reported. The aggregate virtual screen surface for a stationary observer is described, as are guidelines to construct a full-parallax system and the theoretical ability of the present system to project imagery outside of the volume swept by the screen.

  9. 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.

  10. Using a prototype voxel for visualizing volumetric data

    NASA Astrophysics Data System (ADS)

    Buckalew, William C.

    1993-07-01

    We present a method for visualizing volumetric data such as NMI or CAT-scan data that makes use of a data structure called the prototype voxel to create images very quickly on common workstation screens. The algorithm speeds up the standard process of casting rays through the volume data by precomputing a great deal of direction and interpolation information, assuming that all voxels are the same size and shape (which is normally the case for medical data sets). As rays are cast, this information, stored in the prototype voxel, is merely looked up when needed rather than being recomputed repeatedly. The prototype voxel must be computed only once for each data configuration; subsequent data sets which use the same size and shape of voxel can use the same prototype voxel information to speed rendering. This algorithm trades memory for speed: it uses 20 to 50 megabytes of memory (already becoming commonly available in modern workstations) for its speed improvements.

  11. 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.

  12. Illuminating cellular physiology: recent developments.

    PubMed

    Brovko, Lubov Y; Griffiths, Mansel W

    2007-01-01

    Bioluminescent methods are gaining more and more attention among scientists due to their sensitivity, selectivity and simplicity; coupled with the fact that the bioluminescence can be monitored both in vitro and in vivo. Since the discovery of bioluminescence in the 19th century, enzymes involved in the bioluminescent process have been isolated and cloned. The bioluminescent reactions in several different organisms have also been fully characterized and used as reporters in a wide variety of biochemical assays. From the 1990s it became clear that bioluminescence can be detected and quantified directly from inside a living cell. This gave rise to numerous possibilities for the in vivo monitoring of intracellular processes non-invasively using bioluminescent molecules as reporters. This review describes recent developments in the area of bioluminescent imaging for cell biology. Newly developed imaging methods allow transcriptional/translational regulation, signal transduction, protein-protein interaction, oncogenic transformation, cell and protein trafficking, and target drug action to be monitored in vivo in real-time with high temporal and spatial resolution; thus providing researchers with priceless information on cellular functions. Advantages and limitations of these novel bioluminescent methods are discussed and possible future developments identified. PMID:17725230

  13. 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, A.; Lidman, C.; Pain, R.; Pritchet, C.; Ruhlmann-Kleider, V.

    2016-08-01

    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. (2010) 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 (ULGRBs) 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.

  14. 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.

  15. 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.

  16. Volumetric MRI data correlate to disease severity in metachromatic leukodystrophy

    PubMed Central

    Tillema, Jan-Mendelt; Derks, Marloes GM; Pouwels, Petra J W; de Graaf, Pim; van Rappard, Diane F; Barkhof, Frederik; Steenweg, Marjan E; van der Knaap, Marjo S; Wolf, Nicole I

    2015-01-01

    Objective Metachromatic leukodystrophy (MLD) is an inherited lysosomal disorder due to a deficiency in arylsulfatase A with progressive demyelination and neurological decline. This retrospective MRI study investigated the extent of cortical involvement at time of diagnosis, and clinical correlates to both conventional and regional volumetric measures of brain involvement. Methods 3D-T1-weighted MRI scans were used to determine cortical thickness and surface-based cerebral cortical gray matter (GM) and cerebral white matter (WM) volume (GMV and WMV), WM lesions, thalamus, and cerebellum. MRI-MLD severity scores were obtained from FLAIR images. Associations between clinical and imaging data were examined using correlation coefficients. Results Twenty patients with MLD (mean age 13.7 years, range 2–35) and 20 controls (mean age 13.9 years, range 2–40) were included. Compared with control subjects, late-infantile, and juvenile patients (n = 14) had significantly diminished cerebral cortical GMV and thalamus volume (P < 0.05), but did not differ in WMV and cortical thickness. Adult patients (n = 6) showed significantly reduced GMV, WMV and cortical thickness (all P < 0.05). Regional analysis showed statistically significant cortical thinning in the cingulate gyrus and most pronounced thinning with age in the frontal lobe of MLD patients. Intelligence quotient (IQ) correlated with MRI-MLD scores (r = −0.87, P < 0.001). Interpretation Significant cerebral cortical GMV loss is already present in early stages of MLD. IQ correlates with WM severity scores and lesion volume, but not with volumetric measures. In adult presentations, there is more pronounced global atrophy with GMV and WMV loss and accelerated cortical thinning, most prominently in the cingulate gyrus and frontal lobes. PMID:26401514

  17. 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

  18. Control of cellular automata

    NASA Astrophysics Data System (ADS)

    Bagnoli, Franco; Rechtman, Raúl; El Yacoubi, Samira

    2012-12-01

    We study the problem of master-slave synchronization and control of totalistic cellular automata. The synchronization mechanism is that of setting a fraction of sites of the slave system equal to those of the master one (pinching synchronization). The synchronization observable is the distance between the two configurations. We present three control strategies that exploit local information (the number of nonzero first-order Boolean derivatives) in order to choose the sites to be synchronized. When no local information is used, we speak of simple pinching synchronization. We find the critical properties of control and discuss the best control strategy compared with simple synchronization.

  19. 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

  20. Real-time interactive visualization and manipulation of the volumetric data using GPU-based methods

    NASA Astrophysics Data System (ADS)

    Dietrich, Carlos A.; Nedel, Luciana P.; Olabarriaga, Silvia D.; Comba, Joao L. D.; Zanchet, Dinamar J.; Marques da Silva, Ana M.; de Souza Montero, Edna F.

    2004-05-01

    This work presents a set of tools developed to provide 3D visualization and interaction with large volumetric data that relies on recent programmable capabilities of consumer-level graphics cards. We are exploiting the programmable control of calculations performed by the graphics hardware for generating the appearance of each pixel on the screen to develop real-time, interactive volume manipulation tools. These tools allow real-time modification of visualization parameters, such as color and opacity classification or the selection of a volume of interest, extending the benefit of hardware acceleration beyond display, namely for computation of voxel visibility. Three interactive tools are proposed: a cutting tool that allows the selection of a convex volume of interest, an eraser-like tool to eliminate non-relevant parts of the image and a digger-like tool that allows the user to eliminate layers of a 3D image. To interactively apply the proposed tools on a volume, we are making use of some so known user interaction techniques, as the ones used in 2D painting systems. Our strategy is to minimize the user entrainment efforts involved in the tools learning. Finally, we illustrate the potential application of the conceived tools for preoperative planning of liver surgery and for liver vascular anatomy study. Preliminary results concerning the system performance and the images quality and resolution are presented and discussed.

  1. 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.

  2. Demonstration of volumetric analysis using the topographical mapping system at Hanford

    SciTech Connect

    Armstrong, G.A.; Burks, B.L.; Carteret, B.A.; Pardini, A.F.; Samuel, T.J.

    1997-07-01

    During the spring of 1997, the Topographical Mapping System (TMS) for hazardous and radiological environments was used to perform volumetric measurements of simulated waste in the cold test cell in the Fuel Materials and Examination Facility at the Hanford site. The TMS was used to measure the volume of five simulated waste mounds. Custom software designed by Oak Ridge National Laboratory was used to calculate the volume of waste from the surface maps supplied by the TMS. The results of the measurements were analyzed using the Interactive Computer-Enhanced Remote-Viewing System (ICERVS) and were documented. Development of the TMS and ICERVS was initiated by the US Department of Energy (DOE) for the purpose of characterization and remediation of underground storage tanks (USTs) at DOE sites across the country. DOE required a three-dimensional TMS suitable for use in hazardous and radiological environments. The intended application is the mapping of the interior of USTs as part of DOE`s waste characterization and remediation efforts to obtain baseline data on the content of storage tank interiors as well as on changes in the tank contents and levels brought about by waste remediation steps. Initially targeted for deployment at the Hanford site, the TMS was designed to be a self-contained, compact, and reconfigurable system that is capable of providing rapid, variable-resolution mapping information in poorly characterized workspaces with a minimum of operator intervention. An appendix contains the source code for calculating the volume from two surface maps.

  3. 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.

  4. 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

  5. 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

    2015-01-01

    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. PMID:25683656

  6. Enhanced volumetric visualization for real time 4D intraoperative ophthalmic swept-source OCT.

    PubMed

    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

    2016-05-01

    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

  7. Mapping of cellular iron using hyperspectral fluorescence imaging in a cellular model of Parkinson's disease

    NASA Astrophysics Data System (ADS)

    Oh, Eung Seok; Heo, Chaejeong; Kim, Ji Seon; Lee, Young Hee; Kim, Jong Min

    2013-05-01

    Parkinson's disease (PD) is characterized by progressive dopaminergic cell loss in the substantianigra (SN) and elevated iron levels demonstrated by autopsy and with 7-Tesla magnetic resonance imaging. Direct visualization of iron with live imaging techniques has not yet been successful. The aim of this study is to visualize and quantify the distribution of cellular iron using an intrinsic iron hyperspectral fluorescence signal. The 1-methyl-4-phenylpyridinium (MPP+)-induced cellular model of PD was established in SHSY5Y cells. The cells were exposed to iron by treatment with ferric ammonium citrate (FAC, 100 μM) for up to 6 hours. The hyperspectral fluorescence imaging signal of iron was examined usinga high- resolution dark-field optical microscope system with signal absorption for the visible/ near infrared (VNIR) spectral range. The 6-hour group showed heavy cellular iron deposition compared with the small amount of iron accumulation in the 1-hour group. The cellular iron was dispersed in a small, particulate form, whereas extracellular iron was detected in an aggregated form. In addition, iron particles were found to be concentrated on the cell membrane/edge of shrunken cells. The cellular iron accumulation readily occurred in MPP+-induced cells, which is consistent with previous studies demonstrating elevated iron levels in the SN in PD. This direct iron imaging methodology could be applied to analyze the physiological role of iron in PD, and its application might be expanded to various neurological disorders involving other metals, such as copper, manganese or zinc.

  8. 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.

  9. Cellular Contraction and Polarization Drive Collective Cellular Motion.

    PubMed

    Notbohm, Jacob; Banerjee, Shiladitya; Utuje, Kazage J C; Gweon, Bomi; Jang, Hwanseok; Park, Yongdoo; Shin, Jennifer; Butler, James P; Fredberg, Jeffrey J; Marchetti, M Cristina

    2016-06-21

    Coordinated motions of close-packed multicellular systems typically generate cooperative packs, swirls, and clusters. These cooperative motions are driven by active cellular forces, but the physical nature of these forces and how they generate collective cellular motion remain poorly understood. Here, we study forces and motions in a confined epithelial monolayer and make two experimental observations: 1) the direction of local cellular motion deviates systematically from the direction of the local traction exerted by each cell upon its substrate; and 2) oscillating waves of cellular motion arise spontaneously. Based on these observations, we propose a theory that connects forces and motions using two internal state variables, one of which generates an effective cellular polarization, and the other, through contractile forces, an effective cellular inertia. In agreement with theoretical predictions, drugs that inhibit contractility reduce both the cellular effective elastic modulus and the frequency of oscillations. Together, theory and experiment provide evidence suggesting that collective cellular motion is driven by at least two internal variables that serve to sustain waves and to polarize local cellular traction in a direction that deviates systematically from local cellular velocity. PMID:27332131

  10. Volumetric optoacoustic imaging with multi-bandwidth deconvolution.

    PubMed

    Buehler, Andreas; Deán-Ben, X Luís; Razansky, Daniel; Ntziachristos, Vasilis

    2014-04-01

    Optoacoustic (photoacoustic) imaging based on cylindrically focused 1-D transducer arrays comes with powerful characteristics in visualizing optical contrast. Parallel reading of multiple detectors arranged around a tissue cross section enables capturing data for generating images of this plane within micro-seconds. Dedicated small animals scanners and handheld systems using 1-D cylindrically focused ultrasound transducer arrays have demonstrated real-time cross-sectional imaging and high in-plane resolution. Yet, the resolution achieved along the axis perpendicular to the focal plane, i.e., the elevation resolution, is determined by the focusing capacities of the detector and is typically lower than the in-plane resolution. Herein, we investigated whether deconvolution of the sensitivity field of the transducer could lead to tangible image improvements. We showcase the findings on experimental measurements from phantoms and animals and discuss the features and the limitations of the approach in improving resolution along the elevation dimension. PMID:24058023

  11. Integrated cellular systems

    NASA Astrophysics Data System (ADS)

    Harper, Jason C.

    The generation of new three-dimensional (3D) matrices that enable integration of biomolecular components and whole cells into device architectures, without adversely altering their morphology or activity, continues to be an expanding and challenging field of research. This research is driven by the promise that encapsulated biomolecules and cells can significantly impact areas as diverse as biocatalysis, controlled delivery of therapeutics, environmental and industrial process monitoring, early warning of warfare agents, bioelectronics, photonics, smart prosthetics, advanced physiological sensors, portable medical diagnostic devices, and tissue/organ replacement. This work focuses on the development of a fundamental understanding of the biochemical and nanomaterial mechanisms that govern the cell directed assembly and integration process. It was shown that this integration process relies on the ability of cells to actively develop a pH gradient in response to evaporation induced osmotic stress, which catalyzes silica condensation within a thin 3D volume surrounding the cells, creating a functional bio/nano interface. The mechanism responsible for introducing functional foreign membrane-bound proteins via proteoliposome addition to the silica-lipid-cell matrix was also determined. Utilizing this new understanding, 3D cellular immobilization capabilities were extended using sol-gel matrices endowed with glycerol, trehalose, and media components. The effects of these additives, and the metabolic phase of encapsulated S. cerivisiase cells, on long-term viability and the rate of inducible gene expression was studied. This enabled the entrapment of cells within a novel microfluidic platform capable of simultaneous colorimetric, fluorescent, and electrochemical detection of a single analyte, significantly improving confidence in the biosensor output. As a complementary approach, multiphoton protein lithography was utilized to engineer 3D protein matrices in which to

  12. 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

    2016-05-01

    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. PMID:27137614

  13. 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. PMID:27134668

  14. The new kid on the block for advanced imaging in Barrett’s esophagus: a review of volumetric laser endomicroscopy

    PubMed Central

    Trindade, Arvind J.; Smith, Michael S.; Pleskow, Douglas K.

    2016-01-01

    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. PMID:27134668

  15. Nondestructive volumetric imaging of tissue microstructure with benchtop x-ray phase-contrast tomography and critical point drying

    PubMed Central

    Zysk, Adam M.; Garson, Alfred B.; Xu, Qiaofeng; Brey, Eric M.; Zhou, Wei; Brankov, Jovan G.; Wernick, Miles N.; Kuszak, Jerome R.; Anastasio, Mark A.

    2012-01-01

    The in vitro investigation of many optically opaque biological microstructures requires 3D analysis at high resolution over a large field of view. We demonstrate a new nondestructive volumetric imaging technique that eliminates the structural and computational limitations of conventional 2D optical microscopy by combining x-ray phase-contrast tomography with critical point drying sample preparation. We experimentally demonstrate the enhancement of small features afforded by phase-contrast imaging and show the contrast improvement afforded by the drying of a hydrated specimen. We further demonstrate the biological application of this technique by imaging the microstructure of the accommodative apparatus in a primate eye using a benchtop phase-contrast tomography system. PMID:22876355

  16. Dose-related cerebellar abnormality in rats with prenatal exposure to X-irradiation by magnetic resonance imaging volumetric analysis.

    PubMed

    Sawada, Kazuhiko; Saito, Shigeyoshi; Horiuchi-Hirose, Miwa; Mori, Yuki; Yoshioka, Yoshichika; Murase, Kenya

    2013-09-01

    Cerebellar abnormalities in 4-week-old rats with a single whole body X-irradiation at a dose of 0.5, 1.0, or 1.5 Gy on embryonic day (ED) 15 were examined by magnetic resonance imaging (MRI) volumetry. A 3D T2 W-MRI anatomical sequence with high-spatial resolution at 11.7-tesla was acquired from the fixed rat heads. By MRI volumetry, whole cerebellar volumes decreased dose-dependently. Multiple linear regression analysis revealed that the cortical volume (standardized β=0.901; P<0.001) was a major explanatory variable for the whole cerebellar volume, whereas both volumes of the white matter and deep cerebellar nuclei also decreased depending on the X-irradiation dose. The present MRI volumetric analysis revealed a dose-related cerebellar cortical hypoplasia by prenatal exposure to X-irradiation on E15. PMID:23998266

  17. Engineering Cellular Metabolism.

    PubMed

    Nielsen, Jens; Keasling, Jay D

    2016-03-10

    Metabolic engineering is the science of rewiring the metabolism of cells to enhance production of native metabolites or to endow cells with the ability to produce new products. The potential applications of such efforts are wide ranging, including the generation of fuels, chemicals, foods, feeds, and pharmaceuticals. However, making cells into efficient factories is challenging because cells have evolved robust metabolic networks with hard-wired, tightly regulated lines of communication between molecular pathways that resist efforts to divert resources. Here, we will review the current status and challenges of metabolic engineering and will discuss how new technologies can enable metabolic engineering to be scaled up to the industrial level, either by cutting off the lines of control for endogenous metabolism or by infiltrating the system with disruptive, heterologous pathways that overcome cellular regulation. PMID:26967285

  18. Cellular Morphogenesis In Silico

    PubMed Central

    Shinbrot, Troy; Chun, Young; Caicedo-Carvajal, Carlos; Foty, Ramsey

    2009-01-01

    Abstract We describe a model that simulates spherical cells of different types that can migrate and interact either attractively or repulsively. We find that both expected morphologies and previously unreported patterns spontaneously self-assemble. Among the newly discovered patterns are a segmented state of alternating discs, and a “shish-kebab” state, in which one cell type forms a ring around a second type. We show that these unique states result from cellular attraction that increases with distance (e.g., as membranes stretch viscoelastically), and would not be seen in traditional, e.g., molecular, potentials that diminish with distance. Most of the states found computationally have been observed in vitro, and it remains to be established what role these self-assembled states may play in in vivo morphogenesis. PMID:19686642

  19. 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 .

  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. 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

  2. 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

  3. Interleaved imaging of cerebral hemodynamics and blood flow index to monitor ischemic stroke and treatment in rat by volumetric diffuse optical tomography.

    PubMed

    Lin, Zi-Jing; Ren, Ming; Li, Lin; Liu, Yueming; Su, Jianzhong; Yang, Shao-Hua; Liu, Hanli

    2014-01-15

    Diffuse optical tomography (DOT) has been used by several groups to assess cerebral hemodynamics of cerebral ischemia in humans and animals. In this study, we combined DOT with an indocyanine green (ICG)-tracking method to achieve interleaved images of cerebral hemodynamics and blood flow index (BFI) using two middle cerebral artery occlusion (MCAO) rat models. To achieve volumetric images with high-spatial resolution, we first integrated a depth compensation algorithm (DCA) with a volumetric mesh-based rat head model to generate three-dimensional (3D) DOT on a rat brain atlas. Then, the experimental DOT data from two rat models were collected using interleaved strategy for cerebral hemodynamics and BFI during and after ischemic stroke, with and without a thrombolytic therapy for the embolic MCAO model. The acquired animal data were further analyzed using the integrated rat-atlas-guided DOT method to form time-evolving 3D images of both cerebral hemodynamics and BFI. In particular, we were able to show and identify therapeutic outcomes of a thrombolytic treatment applied to the embolism-induced ischemic model. This paper demonstrates that volumetric DOT is capable of providing high-quality, interleaved images of cerebral hemodynamics and blood perfusion in small animals during and after ischemic stroke, with excellent 3D visualization and quantifications. PMID:23872158

  4. Interleaved imaging of cerebral hemodynamics and blood flow index to monitor ischemic stroke and treatment in rat by volumetric diffuse optical tomography

    PubMed Central

    Lin, Zi-Jing; Ren, Ming; Li, Lin; Liu, Yueming; Su, Jianzhong; Yang, Shao-Hua; Liu, Hanli

    2013-01-01

    Diffuse optical tomography (DOT) has been used by several groups to assess cerebral hemodynamics of cerebral ischemia in humans and animals. In this study, we combined DOT with an indocyanine green (ICG)-tracking method to achieve interleaved images of cerebral hemodynamics and blood flow index (BFI) using two middle cerebral artery occlusion (MCAO) rat models. To achieve volumetric images with high-spatial resolution, we first integrated a depth compensation algorithm (DCA) with a volumetric mesh-based rat head model to generate three-dimensional (3D) DOT on a rat brain atlas. Then, the experimental DOT data from two rat models were collected using interleaved strategy for cerebral hemodynamics and BFI during and after ischemic stroke, with and without a thrombolytic therapy for the embolic MCAO model. The acquired animal data were further analyzed using the integrated rat-atlas-guided DOT method to form time-evolving 3D images of both cerebral hemodynamics and BFI. In particular, we were able to show and identify therapeutic outcomes of a thrombolytic treatment applied to the embolism-induced ischemic model. This paper demonstrates that volumetric DOT is capable of providing high-quality, interleaved images of cerebral hemodynamics and blood perfusion in small animals during and after ischemic stroke, with excellent 3D visualization and quantifications. PMID:23872158

  5. 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

  6. Toward a Philosophy and Theory of Volumetric Nonthermal Processing.

    PubMed

    Sastry, Sudhir K

    2016-06-01

    Nonthermal processes for food preservation have been under intensive investigation for about the past quarter century, with varying degrees of success. We focus this discussion on two volumetrically acting nonthermal processes, high pressure processing (HPP) and pulsed electric fields (PEF), with emphasis on scientific understanding of each, and the research questions that need to be addressed for each to be more successful in the future. We discuss the character or "philosophy" of food preservation, with a question about the nature of the kill step(s), and the sensing challenges that need to be addressed. For HPP, key questions and needs center around whether its nonthermal effectiveness can be increased by increased pressures or pulsing, the theoretical treatment of rates of reaction as influenced by pressure, the assumption of uniform pressure distribution, and the need for (and difficulties involved in) in-situ measurement. For PEF, the questions include the rationale for pulsing, difficulties involved in continuous flow treatment chambers, the difference between electroporation theory and experimental observations, and the difficulties involved in in-situ measurement and monitoring of electric field distribution. PMID:27149642

  7. Volumetric velocity measurements of vortex rings from inclined exits

    NASA Astrophysics Data System (ADS)

    Troolin, Daniel R.; Longmire, Ellen K.

    2010-03-01

    Vortex rings were generated by driving pistons within circular cylinders of inner diameter D = 72.8 mm at a constant velocity U 0 over a distance L = D. The Reynolds number, U 0 L/(2ν), was 2500. The flow downstream of circular and inclined exits was examined using volumetric 3-component velocimetry (V3V). The circular exit yields a standard primary vortex ring that propagates downstream at a constant velocity and a lingering trailing ring of opposite sign associated with the stopping of the piston. By contrast, the inclined nozzle yields a much more complicated structure. The data suggest that a tilted primary vortex ring interacts with two trailing rings; one associated with the stopping of the piston, and the other associated with the asymmetry of the cylinder exit. The two trailing ring structures, which initially have circulation of opposite sign, intertwine and are distorted and drawn through the center of the primary ring. This behavior was observed for two inclination angles. Increased inclination was associated with stronger interactions between the primary and trailing vortices as well as earlier breakdown.

  8. Range estimation of cetaceans with compact volumetric arrays.

    PubMed

    Zimmer, Walter M X

    2013-09-01

    Passive acoustic monitoring is the method of choice to detect whales and dolphins that are acoustically active and to monitor their underwater behavior. The NATO Science and Technology Organization Centre for Maritime Research and Experimentation has recently implemented a compact passive acoustic monitor (CPAM), consisting of three arrays of two hydrophones each that are combined in a fixed three-dimensional arrangement and that may be towed at depths of more than 100 m. With its volumetric configuration, the CPAM is capable of estimating the three-dimensional direction vector of arriving sounds and under certain conditions on relative geometry between the whale and hydrophone array, the CPAM may also estimate the range to echolocating animals. Basic ranging methods assume constant sound speed and apply straightforward geometry to obtain depth and distance to the sound source. Alternatively, ray-tracing based methods may be employed to integrate the information provided by real sound speed profiles. Both ranging methods combine measurements of sound arrival angles and surface reflection delays and are easily implemented in real-time applications, whereby one could promote the ray-tracing approach as the preferred method because it may integrate real sound speed profiles. PMID:23968058

  9. Volumetric modulated arc therapy planning for distal oesophageal malignancies

    PubMed Central

    Hawkins, M A; Bedford, J L; Warrington, A P; Tait, D M

    2012-01-01

    Objectives Volumetric modulated arc therapy (VMAT) is a novel form of intensity-modulated radiation therapy that allows the radiation dose to be delivered in a single gantry rotation using conformal or modulated fields. The capability of VMAT to reduce heart and cord dose, while maintaining lung receiving 20 Gy <20%, was evaluated for chemoradiation for oesophageal cancer. Methods An optimised forward-planned four-field arrangement was compared with inverse-planned coplanar VMAT arcs with 35 control points for 10 patients with lower gastro-oesophageal tumours prescribed 54 Gy in 30 fractions. Conformal (cARC) and intensity-modulated (VMATi) arcs were considered. Plans were assessed and compared using the planning target volume (PTV) irradiated to 95% of the prescription dose (V95), volumes of lung irradiated to 20 Gy (V20), heart irradiated to 30 Gy (V30), spinal cord maximum dose and van't Riet conformation number (CN). The monitor units per fraction and delivery time were recorded for a single representative plan. Results VMATi provided a significant reduction in the heart V30 (31% vs 55%; p=0.02) with better CN (0.72 vs 0.65; p=0.01) than the conformal plan. The treatment delivery was 1 min 28 s for VMAT compared with 3 min 15 s. Conclusion For similar PTV coverage, VMATi delivers a lower dose to organs at risk than conformal plans in a shorter time, and this has warranted clinical implementation. PMID:21427179

  10. Interactive Visualization of Solar Mass Ejection Imager (SMEI) Volumetric Data

    NASA Astrophysics Data System (ADS)

    Wang, X.; Hick, P. P.; Jackson, B. V.

    2004-12-01

    We present a volume rendering system developed for the real time visualization and manipulation of 3D heliospheric volumetric solar wind density and velocity data obtained from the Solar Mass Ejection Imager (SMEI) and interplanetary scintillation (IPS) velocities over the same time period. Our system exploits the capabilities of the VolumePro 1000 board from TeraRecon, Inc., a low-cost 64-bit PCI board capable of rendering up to a 512-cubed array of volume data in real time at up to 30 frames per second on a standard PC. Many volume-rendering operations have been implemented with this system such as stereo/perspective views, animations of time-sequences, and determination of CME volumes and masses. In these visualizations we highlight two time periods where halo CMEs were observed by SMEI to engulf Earth, on May 30, 2003 and on October 29, 2003. We demonstrate how this system is used to measure the distribution of structure and provide 3D mass for individual CME features, including the ejecta associated with the large prominence viewed moving to the south of Earth following the late October CME.

  11. Iterative Reconstruction of Volumetric Particle Distribution for 3D Velocimetry

    NASA Astrophysics Data System (ADS)

    Wieneke, Bernhard; Neal, Douglas

    2011-11-01

    A number of different volumetric flow measurement techniques exist for following the motion of illuminated particles. For experiments that have lower seeding densities, 3D-PTV uses recorded images from typically 3-4 cameras and then tracks the individual particles in space and time. This technique is effective in flows that have lower seeding densities. For flows that have a higher seeding density, tomographic PIV uses a tomographic reconstruction algorithm (e.g. MART) to reconstruct voxel intensities of the recorded volume followed by the cross-correlation of subvolumes to provide the instantaneous 3D vector fields on a regular grid. A new hybrid algorithm is presented which iteratively reconstructs the 3D-particle distribution directly using particles with certain imaging properties instead of voxels as base functions. It is shown with synthetic data that this method is capable of reconstructing densely seeded flows up to 0.05 particles per pixel (ppp) with the same or higher accuracy than 3D-PTV and tomographic PIV. Finally, this new method is validated using experimental data on a turbulent jet.

  12. 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.

  13. Volumetric associations between uncinate fasciculus, amygdala, and trait anxiety

    PubMed Central

    2012-01-01

    Background Recent investigations of white matter (WM) connectivity suggest an important role of the uncinate fasciculus (UF), connecting anterior temporal areas including the amygdala with prefrontal-/orbitofrontal cortices, for anxiety-related processes. Volume of the UF, however, has rarely been investigated, but may be an important measure of structural connectivity underlying limbic neuronal circuits associated with anxiety. Since UF volumetric measures are newly applied measures, it is necessary to cross-validate them using further neural and behavioral indicators of anxiety. Results In a group of 32 subjects not reporting any history of psychiatric disorders, we identified a negative correlation between left UF volume and trait anxiety, a finding that is in line with previous results. On the other hand, volume of the left amygdala, which is strongly connected with the UF, was positively correlated with trait anxiety. In addition, volumes of the left UF and left amygdala were inversely associated. Conclusions The present study emphasizes the role of the left UF as candidate WM fiber bundle associated with anxiety-related processes and suggests that fiber bundle volume is a WM measure of particular interest. Moreover, these results substantiate the structural relatedness of UF and amygdala by a non-invasive imaging method. The UF-amygdala complex may be pivotal for the control of trait anxiety. PMID:22217209

  14. 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.

  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. PMID:26390481

  16. 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

  17. Application of cone beam volumetric tomography in endodontics.

    PubMed

    Tyndall, D A; Kohltfarber, H

    2012-11-01

    In a 2008 article on cone beam volumetric tomography (CBVT) and dentoalveolar applications, Tyndall and Rathore wrote: "It is in the area of endodontic applications that the literature has proved most fruitful to date." This statement is even truer today than in 2008. A review of the literature has demonstrated that, in many cases, CBVT is more efficacious than traditional forms of 2-D imaging. Endodontic applications of CBVT include the diagnosis of periapical lesions due to pulpal inflammation, identification, and localization of internal and external resorption, the detection of vertical root fractures, the visualization of accessory canals, and elucidation of the causes of non-healing endodontically treated teeth. Prior to 2008, most published articles on CBVT applications in endodontics were either case reports or in vitro studies. Since that time more well designed clinically related scholarly activity has been published. This article attempts to survey the field of CBVT applications in endodontics and provide the readers with an overview of what has been found. The authors hope that this knowledge will form a foundation for appropriate clinical decision making with specific reference to selection criteria for the endodontic applications of CBVT. PMID:23487892

  18. Application of cone beam volumetric tomography in endodontics.

    PubMed

    Tyndall, Donald A; Kohltfarber, H

    2012-03-01

    In a 2008 article on cone beam volumetric tomography (CBVT) and dentoalveolar applications, Tyndall and Rathore wrote: 'It is in the area of endodontic applications that the literature has proved most fruitful to date.' This statement is even truer today than in 2008. A review of the literature has demonstrated that, in many cases, CBVT is more efficacious than traditional forms of 2-D imaging. Endodontic applications of CBVT include the diagnosis of periapical lesions due to pulpal inflammation, identification and localization of internal and external resorption, the detection of vertical root fractures, the visualization of accessory canals, and elucidation of the causes of non-healing endodontically treated teeth. Prior to 2008, most published articles on CBVT applications in endodontics were either case reports or in vitro studies. Since that time more well designed clinically related scholarly activity has been published. This article attempts to survey the field of CBVT applications in endodontics and provide the readers with an overview of what has been found. The authors hope that this knowledge will form a foundation for appropriate clinical decision making with specific reference to selection criteria for the endodontic applications of CBVT. PMID:22376099

  19. Molecular and Cellular Biophysics

    NASA Astrophysics Data System (ADS)

    Jackson, Meyer B.

    2006-01-01

    Molecular and Cellular Biophysics provides advanced undergraduate and graduate students with a foundation in the basic concepts of biophysics. Students who have taken physical chemistry and calculus courses will find this book an accessible and valuable aid in learning how these concepts can be used in biological research. The text provides a rigorous treatment of the fundamental theories in biophysics and illustrates their application with examples. Conformational transitions of proteins are studied first using thermodynamics, and subsequently with kinetics. Allosteric theory is developed as the synthesis of conformational transitions and association reactions. Basic ideas of thermodynamics and kinetics are applied to topics such as protein folding, enzyme catalysis and ion channel permeation. These concepts are then used as the building blocks in a treatment of membrane excitability. Through these examples, students will gain an understanding of the general importance and broad applicability of biophysical principles to biological problems. Offers a unique synthesis of concepts across a wide range of biophysical topics Provides a rigorous theoretical treatment, alongside applications in biological systems Author has been teaching biophysics for nearly 25 years

  20. Electrosurgery with cellular precision.

    PubMed

    Palanker, Daniel V; Vankov, Alexander; Huie, Philip

    2008-02-01

    Electrosurgery, one of the most-often used surgical tools, is a robust but somewhat crude technology that has changed surprisingly little since its invention almost a century ago. Continuous radiofrequency is still used for tissue cutting, with thermal damage extending to hundreds of micrometers. In contrast, lasers developed 70 years later, have been constantly perfected, and the laser-tissue interactions explored in great detail, which has allowed tissue ablation with cellular precision in many laser applications. We discuss mechanisms of tissue damage by electric field, and demonstrate that electrosurgery with properly optimized waveforms and microelectrodes can rival many advanced lasers. Pulsed electric waveforms with burst durations ranging from 10 to 100 micros applied via insulated planar electrodes with 12 microm wide exposed edges produced plasma-mediated dissection of tissues with the collateral damage zone ranging from 2 to 10 microm. Length of the electrodes can vary from micrometers to centimeters and all types of soft tissues-from membranes to cartilage and skin could be dissected in liquid medium and in a dry field. This technology may allow for major improvements in outcomes of the current surgical procedures and development of much more refined surgical techniques. PMID:18270030

  1. Active Cellular Nematics

    NASA Astrophysics Data System (ADS)

    Duclos, Guillaume; Erlenkaemper, Christoph; Garcia, Simon; Yevick, Hannah; Joanny, Jean-François; Silberzan, Pascal; Biology inspired physics at mesoscales Team; Physical approach of biological problems Team

    We study the emergence of a nematic order in a two-dimensional tissue of apolar elongated fibroblast cells. Initially, these cells are very motile and the monolayer is characterized by giant density fluctuations, a signature of far-from-equilibrium systems. As the cell density increases because of proliferation, the cells align with each other forming large perfectly oriented domains while the cellular movements slow down and eventually freeze. Therefore topological defects characteristic of nematic phases remain trapped at long times, preventing the development of infinite domains. By analogy with classical non-active nematics, we have investigated the role of boundaries and we have shown that cells confined in stripes of width smaller than typically 500 µm are perfectly aligned in the stripe direction. Experiments performed in cross-shaped patterns show that both the number of cells and the degree of alignment impact the final orientation. Reference: Duclos G., Garcia S., Yevick H.G. and Silberzan P., ''Perfect nematic order in confined monolayers of spindle-shaped cells'', Soft Matter, 10, 14, 2014

  2. 47 CFR 22.909 - Cellular markets.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 2 2013-10-01 2013-10-01 false Cellular markets. 22.909 Section 22.909... Cellular Radiotelephone Service § 22.909 Cellular markets. Cellular markets are standard geographic areas used by the FCC for administrative convenience in the licensing of cellular systems. Cellular...

  3. 47 CFR 22.909 - Cellular markets.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 2 2014-10-01 2014-10-01 false Cellular markets. 22.909 Section 22.909... Cellular Radiotelephone Service § 22.909 Cellular markets. Cellular markets are standard geographic areas used by the FCC for administrative convenience in the licensing of cellular systems. Cellular...

  4. Mechanical properties, volumetric shrinkage and depth of cure of short fiber-reinforced resin composite.

    PubMed

    Tsujimoto, Akimasa; Barkmeier, Wayne W; Takamizawa, Toshiki; Latta, Mark A; Miyazaki, Masashi

    2016-01-01

    The mechanical properties, volumetric shrinkage and depth of cure of a short fiber-reinforced resin composite (SFRC) were investigated in this study and compared to both a bulk fill resin composite (BFRC) and conventional glass/ceramic-filled resin composite (CGRC). Fracture toughness, flexural properties, volumetric shrinkage and depth of cure of the SFRC, BFRC and CGRC were measured. SFRC had significantly higher fracture toughness than BFRCs and CGRCs. The flexural properties of SFRC were comparable with BFRCs and CGRCs. SFRC showed significantly lower volumetric shrinkage than the other tested resin composites. The depth of cure of the SFRC was similar to BFRCs and higher than CGRCs. The data from this laboratory investigation suggests that SFRC exhibits improvements in fracture toughness, volumetric shrinkage and depth of cure when compared with CGRC, but depth of cure of SFRC was similar to BFRC. PMID:27251997

  5. The Effect of Volumetric Porosity on Roughness Element Drag

    NASA Astrophysics Data System (ADS)

    Gillies, John; Nickling, William; Nikolich, George; Etyemezian, Vicken

    2016-04-01

    Much attention has been given to understanding how the porosity of two dimensional structures affects the drag force exerted by boundary-layer flow on these flow obstructions. Porous structures such as wind breaks and fences are typically used to control the sedimentation of sand and snow particles or create micro-habitats in their lee. Vegetation in drylands also exerts control on sediment transport by wind due to aerodynamic effects and interaction with particles in transport. Recent research has also demonstrated that large spatial arrays of solid three dimensional roughness elements can be used to reduce sand transport to specified targets for control of wind erosion through the effect of drag partitioning and interaction of the moving sand with the large (>0.3 m high) roughness elements, but porous elements may improve the effectiveness of this approach. A thorough understanding of the role porosity plays in affecting the drag force on three-dimensional forms is lacking. To provide basic understanding of the relationship between the porosity of roughness elements and the force of drag exerted on them by fluid flow, we undertook a wind tunnel study that systematically altered the porosity of roughness elements of defined geometry (cubes, rectangular cylinders, and round cylinders) and measured the associated change in the drag force on the elements under similar Reynolds number conditions. The elements tested were of four basic forms: 1) same sized cubes with tubes of known diameter milled through them creating three volumetric porosity values and increasing connectivity between the tubes, 2) cubes and rectangular cylinders constructed of brass screen that nested within each other, and 3) round cylinders constructed of brass screen that nested within each other. The two-dimensional porosity, defined as the ratio of total surface area of the empty space to the solid surface area of the side of the element presented to the fluid flow was conserved at 0.519 for

  6. Semiautomatic segmentation of liver metastases on volumetric CT images

    SciTech Connect

    Yan, Jiayong; Schwartz, Lawrence H.; Zhao, Binsheng

    2015-11-15

    Purpose: Accurate segmentation and quantification of liver metastases on CT images are critical to surgery/radiation treatment planning and therapy response assessment. To date, there are no reliable methods to perform such segmentation automatically. In this work, the authors present a method for semiautomatic delineation of liver metastases on contrast-enhanced volumetric CT images. Methods: The first step is to manually place a seed region-of-interest (ROI) in the lesion on an image. This ROI will (1) serve as an internal marker and (2) assist in automatically identifying an external marker. With these two markers, lesion contour on the image can be accurately delineated using traditional watershed transformation. Density information will then be extracted from the segmented 2D lesion and help determine the 3D connected object that is a candidate of the lesion volume. The authors have developed a robust strategy to automatically determine internal and external markers for marker-controlled watershed segmentation. By manually placing a seed region-of-interest in the lesion to be delineated on a reference image, the method can automatically determine dual threshold values to approximately separate the lesion from its surrounding structures and refine the thresholds from the segmented lesion for the accurate segmentation of the lesion volume. This method was applied to 69 liver metastases (1.1–10.3 cm in diameter) from a total of 15 patients. An independent radiologist manually delineated all lesions and the resultant lesion volumes served as the “gold standard” for validation of the method’s accuracy. Results: The algorithm received a median overlap, overestimation ratio, and underestimation ratio of 82.3%, 6.0%, and 11.5%, respectively, and a median average boundary distance of 1.2 mm. Conclusions: Preliminary results have shown that volumes of liver metastases on contrast-enhanced CT images can be accurately estimated by a semiautomatic segmentation

  7. Evaluation of the Malvern optical particle monitor. [Volumetric size distribution

    SciTech Connect

    Anderson, R. J.; Johnson, E.

    1983-07-01

    The Malvern 2200/3300 Particle Sizer is a laser-based optical particle sizing device which utilizes the principle of Fraunhofer Diffraction as the means of particle size measurement. The instrument is designed to analyze particle sizes in the range of 1 to 1800 microns diameter through a selection of lenses for the receiving optics. It is not a single-particle counter but rather an ensemble averager over the distribution of particles present in the measuring volume. Through appropriate measurement techniques, the instrument can measure the volumetric size distribution of: solids in gas or liquid suspension; liquid droplets in gas or other immiscible liquids; and, gas bubbles in liquid. (Malvern Handbook, Version 1.5). This report details a limited laboratory evaluation of the Malvern system to determine its operational characteristics, limitations, and accuracy. This investigation focused on relatively small particles in the range of 5 to 150 microns. Primarily, well characterized particles of coal in a coal and water mixture were utilized, but a selection of naturally occurring, industrially generated, and standard samples (i.e., glass beads) wer also tested. The characteristic size parameter from the Malvern system for each of these samples was compared with the results of a Coulter particle counter (Model TA II) analysis to determine the size measurement accuracy. Most of the particulate samples were suspended in a liquid media (water or isoton, plus a dispersant) for the size characterization. Specifically, the investigations contained in this report fall into four categories: (a) Sample-to-lense distance and sample concentration studies, (b) studies testing the applicability to aerosols, (c) tests of the manufacturer supplied software, and (d) size measurement comparisons with the results of Coulter analysis. 5 references, 15 figures, 2 tables.

  8. Radiofrequency volumetric inferior turbinate reduction: long-term clinical results.

    PubMed

    De Corso, E; Bastanza, G; Di Donfrancesco, V; Guidi, M L; Morelli Sbarra, G; Passali, G C; Poscia, A; de Waure, C; Paludetti, G; Galli, J

    2016-06-01

    The aim of our study was to assess long-term results of radiofrequency volumetric tissue reduction of inferior turbinates (RVTR). We performed a prospective long-term longitudinal evaluation of 305 patients affected by rhinitis (114 allergic and 191 non-allergic) who were unresponsive to medical treatment and underwent RVTR (January 2004 - December 2010). Subjects were followed for a mean period of 39.70 ± 19.41 months (range 24-60). Patients completed the NOSE-scale questionnaire pre- and post-operatively after 1 month and yearly for 5-years. Recurrence was assumed if the post-operative total NOSE score increased by at least 75% during follow-up and the patient restarted medical treatments. Estimation of relapse over time was performed by Kaplan-Meyer analyses. We documented overall good satisfaction of patients regarding the procedure, with a good rate of pain control and a low rate of complications. Post-operatively there was a significant improvement in nasal stuffiness, nasal obstruction and mouth breathing (p < 0.05). We observed a worsening trend for symptoms after 36 months with progressive increasing rate of recurrences that were significantly higher in allergic than non-allergic patients (p < 0.05). We also observed a slight worsening trend of global satisfaction of patients. Our study confirms the minor discomfort and low risk of side effects of RVTR. Our data showed good efficacy of the procedure in the majority of patients for at least 36 months after surgery, and in fact in this time period the cumulative probability to remain relapse-free was up to 0.8. In the following 2 years, we observed a worse temporal trend in term of recurrence rate, and in particular in allergic patients with a significant difference vs non-allergic individuals (p < 0.05). PMID:27214831

  9. Reflection impulsivity in binge drinking: behavioural and volumetric correlates.

    PubMed

    Banca, Paula; Lange, Iris; Worbe, Yulia; Howell, Nicholas A; Irvine, Michael; Harrison, Neil A; Moutoussis, Michael; Voon, Valerie

    2016-03-01

    The degree to which an individual accumulates evidence prior to making a decision, also known as reflection impulsivity, can be affected in psychiatric disorders. Here, we study decisional impulsivity in binge drinkers, a group at elevated risk for developing alcohol use disorders, comparing two tasks assessing reflection impulsivity and a delay discounting task, hypothesizing impairments in both subtypes of impulsivity. We also assess volumetric correlates of reflection impulsivity focusing on regions previously implicated in functional magnetic resonance imaging studies. Sixty binge drinkers and healthy volunteers were tested using two different information-gathering paradigms: the beads task and the Information Sampling Task (IST). The beads task was analysed using a behavioural approach and a Bayesian model of decision making. Delay discounting was assessed using the Monetary Choice Questionnaire. Regression analyses of primary outcomes were conducted with voxel-based morphometry analyses. Binge drinkers sought less evidence prior to decision in the beads task compared with healthy volunteers in both the behavioural and computational modelling analysis. There were no group differences in the IST or delay discounting task. Greater impulsivity as indexed by lower evidence accumulation in the beads task was associated with smaller dorsolateral prefrontal cortex and inferior parietal volumes. In contrast, greater impulsivity as indexed by lower evidence accumulation in the IST was associated with greater dorsal cingulate and precuneus volumes. Binge drinking is characterized by impaired reflection impulsivity suggesting a deficit in deciding on the basis of future outcomes that are more difficult to represent. These findings emphasize the role of possible therapeutic interventions targeting decision-making deficits. PMID:25678093

  10. Application of AAPM TG 119 to volumetric arc therapy (VMAT).

    PubMed

    Mynampati, Dinesh Kumar; Yaparpalvi, Ravindra; Hong, Linda; Kuo, Hsiang-Chi; Mah, Dennis

    2012-01-01

    The purpose of this study was to create AAPM TG 119 benchmark plans for volumetric arc therapy (VMAT) and to compare VMAT plans with IMRT plan data. AAPM TG 119 proposes a set of test clinical cases for testing the accuracy of IMRT planning and delivery system. For these test cases, we generated two treatment plans, the first plan using 7-9 static dMLC IMRT fields and a second plan utilizing one- or two-arc VMAT technique. Dose optimization and calculations performed using 6 MV photons and Eclipse treatment planning system. Dose prescription and planning objectives were set according to the TG 119 goals. Plans were scored based on TG 119 planning objectives. Treatment plans were compared using conformity index (CI) for reference dose and homogeneity index (HI) (for D(5)-D(95)). For test cases prostate, head-and-neck, C-shape and multitarget prescription dose are 75.6 Gy, 50.4 Gy, 50 Gy and 50 Gy, respectively. VMAT dose distributions were comparable to dMLC IMRT plans. Our planning results matched TG 119 planning results. For treatment plans studied, conformity indices ranged from 1.05-1.23 (IMRT) and 1.04-1.23 (VMAT). Homogeneity indices ranged from 4.6%-11.0% (IMRT) and 4.6%-10.5% (VMAT). The ratio of total monitor units necessary for dMLC IMRT to that of VMAT was in the range of 1.1-2.0. AAPM TG 119 test cases are useful to generate VMAT benchmark plans. At preclinical implementation stage, plan comparison of VMAT and IMRT plans of AAPM TG 119 test case allowed us to understand basic capabilities of VMAT technique. PMID:22955639

  11. Reflection impulsivity in binge drinking: behavioural and volumetric correlates

    PubMed Central

    Banca, Paula; Lange, Iris; Worbe, Yulia; Howell, Nicholas A.; Irvine, Michael; Harrison, Neil A.; Moutoussis, Michael

    2015-01-01

    Abstract The degree to which an individual accumulates evidence prior to making a decision, also known as reflection impulsivity, can be affected in psychiatric disorders. Here, we study decisional impulsivity in binge drinkers, a group at elevated risk for developing alcohol use disorders, comparing two tasks assessing reflection impulsivity and a delay discounting task, hypothesizing impairments in both subtypes of impulsivity. We also assess volumetric correlates of reflection impulsivity focusing on regions previously implicated in functional magnetic resonance imaging studies. Sixty binge drinkers and healthy volunteers were tested using two different information‐gathering paradigms: the beads task and the Information Sampling Task (IST). The beads task was analysed using a behavioural approach and a Bayesian model of decision making. Delay discounting was assessed using the Monetary Choice Questionnaire. Regression analyses of primary outcomes were conducted with voxel‐based morphometry analyses. Binge drinkers sought less evidence prior to decision in the beads task compared with healthy volunteers in both the behavioural and computational modelling analysis. There were no group differences in the IST or delay discounting task. Greater impulsivity as indexed by lower evidence accumulation in the beads task was associated with smaller dorsolateral prefrontal cortex and inferior parietal volumes. In contrast, greater impulsivity as indexed by lower evidence accumulation in the IST was associated with greater dorsal cingulate and precuneus volumes. Binge drinking is characterized by impaired reflection impulsivity suggesting a deficit in deciding on the basis of future outcomes that are more difficult to represent. These findings emphasize the role of possible therapeutic interventions targeting decision‐making deficits. PMID:25678093

  12. Quality assurance of dynamic parameters in volumetric modulated arc therapy

    PubMed Central

    Manikandan, A; Sarkar, B; Holla, R; Vivek, T R; Sujatha, N

    2012-01-01

    Objectives The purpose of this study was to demonstrate quality assurance checks for accuracy of gantry speed and position, dose rate and multileaf collimator (MLC) speed and position for a volumetric modulated arc treatment (VMAT) modality (Synergy® S; Elekta, Stockholm, Sweden), and to check that all the necessary variables and parameters were synchronous. Methods Three tests (for gantry position–dose delivery synchronisation, gantry speed–dose delivery synchronisation and MLC leaf speed and positions) were performed. Results The average error in gantry position was 0.5° and the average difference was 3 MU for a linear and a parabolic relationship between gantry position and delivered dose. In the third part of this test (sawtooth variation), the maximum difference was 9.3 MU, with a gantry position difference of 1.2°. In the sweeping field method test, a linear relationship was observed between recorded doses and distance from the central axis, as expected. In the open field method, errors were encountered at the beginning and at the end of the delivery arc, termed the “beginning” and “end” errors. For MLC position verification, the maximum error was −2.46 mm and the mean error was 0.0153 ±0.4668 mm, and 3.4% of leaves analysed showed errors of >±1 mm. Conclusion This experiment demonstrates that the variables and parameters of the Synergy® S are synchronous and that the system is suitable for delivering VMAT using a dynamic MLC. PMID:22745206

  13. Estimation of Volumetric Breast Density from Digital Mammograms

    NASA Astrophysics Data System (ADS)

    Alonzo-Proulx, Olivier

    Mammographic breast density (MBD) is a strong risk factor for developing breast cancer. MBD is typically estimated by manually selecting the area occupied by the dense tissue on a mammogram. There is interest in measuring the volume of dense tissue, or volumetric breast density (VBD), as it could potentially be a stronger risk factor. This dissertation presents and validates an algorithm to measure the VBD from digital mammograms. The algorithm is based on an empirical calibration of the mammography system, supplemented by physical modeling of x-ray imaging that includes the effects of beam polychromaticity, scattered radation, anti-scatter grid and detector glare. It also includes a method to estimate the compressed breast thickness as a function of the compression force, and a method to estimate the thickness of the breast outside of the compressed region. The algorithm was tested on 26 simulated mammograms obtained from computed tomography images, themselves deformed to mimic the effects of compression. This allowed the determination of the baseline accuracy of the algorithm. The algorithm was also used on 55 087 clinical digital mammograms, which allowed for the determination of the general characteristics of VBD and breast volume, as well as their variation as a function of age and time. The algorithm was also validated against a set of 80 magnetic resonance images, and compared against the area method on 2688 images. A preliminary study comparing association of breast cancer risk with VBD and MBD was also performed, indicating that VBD is a stronger risk factor. The algorithm was found to be accurate, generating quantitative density measurements rapidly and automatically. It can be extended to any digital mammography system, provided that the compression thickness of the breast can be determined accurately.

  14. Blockwise conjugate gradient methods for image reconstruction in volumetric CT.

    PubMed

    Qiu, W; Titley-Peloquin, D; Soleimani, M

    2012-11-01

    Cone beam computed tomography (CBCT) enables volumetric image reconstruction from 2D projection data and plays an important role in image guided radiation therapy (IGRT). Filtered back projection is still the most frequently used algorithm in applications. The algorithm discretizes the scanning process (forward projection) into a system of linear equations, which must then be solved to recover images from measured projection data. The conjugate gradients (CG) algorithm and its variants can be used to solve (possibly regularized) linear systems of equations Ax=b and linear least squares problems minx∥b-Ax∥2, especially when the matrix A is very large and sparse. Their applications can be found in a general CT context, but in tomography problems (e.g. CBCT reconstruction) they have not widely been used. Hence, CBCT reconstruction using the CG-type algorithm LSQR was implemented and studied in this paper. In CBCT reconstruction, the main computational challenge is that the matrix A usually is very large, and storing it in full requires an amount of memory well beyond the reach of commodity computers. Because of these memory capacity constraints, only a small fraction of the weighting matrix A is typically used, leading to a poor reconstruction. In this paper, to overcome this difficulty, the matrix A is partitioned and stored blockwise, and blockwise matrix-vector multiplications are implemented within LSQR. This implementation allows us to use the full weighting matrix A for CBCT reconstruction without further enhancing computer standards. Tikhonov regularization can also be implemented in this fashion, and can produce significant improvement in the reconstructed images. PMID:22325240

  15. Vascular structures for volumetric cooling and mechanical strength

    NASA Astrophysics Data System (ADS)

    Wang, K.-M.; Lorente, S.; Bejan, A.

    2010-02-01

    When solid material is removed in order to create flow channels in a load carrying structure, the strength of the structure decreases. On the other hand, a structure with channels is lighter and easier to transport as part of a vehicle. Here, we show that this trade off can be used for benefit, to design a vascular mechanical structure. When the total amount of solid is fixed and the sizes, shapes, and positions of the channels can vary, it is possible to morph the flow architecture such that it endows the mechanical structure with maximum strength. The result is a multifunctional structure that offers not only mechanical strength but also new capabilities necessary for volumetric functionalities such as self-healing and self-cooling. We illustrate the generation of such designs for strength and fluid flow for several classes of vasculatures: parallel channels, trees with one, two, and three bifurcation levels. The flow regime in every channel is laminar and fully developed. In each case, we found that it is possible to select not only the channel dimensions but also their positions such that the entire structure offers more strength and less flow resistance when the total volume (or weight) and the total channel volume are fixed. We show that the minimized peak stress is smaller when the channel volume (ϕ) is smaller and the vasculature is more complex, i.e., with more levels of bifurcation. Diminishing returns are reached in both directions, decreasing ϕ and increasing complexity. For example, when ϕ =0.02 the minimized peak stress of a design with one bifurcation level is only 0.2% greater than the peak stress in the optimized vascular design with two levels of bifurcation.

  16. A z gain nonuniformity correction for multislice volumetric CT scanners.

    PubMed

    Besson, G; Hu, H; Xie, M; He, D; Seidenschnur, G; Bromberg, N

    2000-05-01

    This paper presents a calibration and correction method for detector cell gain variations. A key functionality of current CT scanners is to offer variable slice thickness to the user. To provide this capability in multislice volumetric scanners, while minimizing costs, it is necessary to combine the signals of several detector cells in z, when the desired slice thickness is larger than the minimum provided by a single cell. These combined signals are then pre-amplified, digitized, and transmitted to the system for further processing. The process of combining the output of several detector cells with nonuniform gains can introduce numerical errors when the impinging x-ray signal presents a variation along z over the range of combined cells. These numerical errors, which by nature are scan dependent, can lead to artifacts in the reconstructed images, particularly when the numerical errors vary from channel-to-channel (as the filtered-backprojection filter includes a high-pass filtering along the channel direction, within a given slice). A projection data correction algorithm has been developed to subtract the associated numerical errors. It relies on the ability of calibrating the individual cell gains. For effectiveness and data flow reasons, the algorithm works on a single slice basis, without slice-to-slice exchange of information. An initial error vector is calculated by applying a high-pass filter to the projection data. The essence of the algorithm is to correlate that initial error vector, with a calibration vector obtained by applying the same high-pass filter to various z combinations of the cell gains (each combination representing a basis function for a z expansion). The solution of the least-square problem, obtained via singular value decomposition, gives the coefficients of a polynomial expansion of the signal z slope and curvature. From this information, and given the cell gains, the final error vector is calculated and subtracted from the projection

  17. Ultrafast treatment plan optimization for volumetric modulated arc therapy (VMAT)

    SciTech Connect

    Men Chunhua; Romeijn, H. Edwin; Jia Xun; Jiang, Steve B.

    2010-11-15

    Purpose: To develop a novel aperture-based algorithm for volumetric modulated arc therapy (VMAT) treatment plan optimization with high quality and high efficiency. Methods: The VMAT optimization problem is formulated as a large-scale convex programming problem solved by a column generation approach. The authors consider a cost function consisting two terms, the first enforcing a desired dose distribution and the second guaranteeing a smooth dose rate variation between successive gantry angles. A gantry rotation is discretized into 180 beam angles and for each beam angle, only one MLC aperture is allowed. The apertures are generated one by one in a sequential way. At each iteration of the column generation method, a deliverable MLC aperture is generated for one of the unoccupied beam angles by solving a subproblem with the consideration of MLC mechanic constraints. A subsequent master problem is then solved to determine the dose rate at all currently generated apertures by minimizing the cost function. When all 180 beam angles are occupied, the optimization completes, yielding a set of deliverable apertures and associated dose rates that produce a high quality plan. Results: The algorithm was preliminarily tested on five prostate and five head-and-neck clinical cases, each with one full gantry rotation without any couch/collimator rotations. High quality VMAT plans have been generated for all ten cases with extremely high efficiency. It takes only 5-8 min on CPU (MATLAB code on an Intel Xeon 2.27 GHz CPU) and 18-31 s on GPU (CUDA code on an NVIDIA Tesla C1060 GPU card) to generate such plans. Conclusions: The authors have developed an aperture-based VMAT optimization algorithm which can generate clinically deliverable high quality treatment plans at very high efficiency.

  18. The power-proportion method for intracranial volume correction in volumetric imaging analysis

    PubMed Central

    Liu, Dawei; Johnson, Hans J.; Long, Jeffrey D.; Magnotta, Vincent A.; Paulsen, Jane S.

    2014-01-01

    In volumetric brain imaging analysis, volumes of brain structures are typically assumed to be proportional or linearly related to intracranial volume (ICV). However, evidence abounds that many brain structures have power law relationships with ICV. To take this relationship into account in volumetric imaging analysis, we propose a power law based method—the power-proportion method—for ICV correction. The performance of the new method is demonstrated using data from the PREDICT-HD study. PMID:25414635

  19. MSAT and cellular hybrid networking

    NASA Technical Reports Server (NTRS)

    Baranowsky, Patrick W., II

    1993-01-01

    Westinghouse Electric Corporation is developing both the Communications Ground Segment and the Series 1000 Mobile Phone for American Mobile Satellite Corporation's (AMSC's) Mobile Satellite (MSAT) system. The success of the voice services portion of this system depends, to some extent, upon the interoperability of the cellular network and the satellite communication circuit switched communication channels. This paper will describe the set of user-selectable cellular interoperable modes (cellular first/satellite second, etc.) provided by the Mobile Phone and described how they are implemented with the ground segment. Topics including roaming registration and cellular-to-satellite 'seamless' call handoff will be discussed, along with the relevant Interim Standard IS-41 Revision B Cellular Radiotelecommunications Intersystem Operations and IOS-553 Mobile Station - Land Station Compatibility Specification.

  20. 3D volumetric modeling of grapevine biomass using Tripod LiDAR

    USGS Publications Warehouse

    Keightley, K.E.; Bawden, G.W.

    2010-01-01

    Tripod mounted laser scanning provides the means to generate high-resolution volumetric measures of vegetation structure and perennial woody tissue for the calculation of standing biomass in agronomic and natural ecosystems. Other than costly destructive harvest methods, no technique exists to rapidly and accurately measure above-ground perennial tissue for woody plants such as Vitis vinifera (common grape vine). Data collected from grapevine trunks and cordons were used to study the accuracy of wood volume derived from laser scanning as compared with volume derived from analog measurements. A set of 10 laser scan datasets were collected for each of 36 vines from which volume was calculated using combinations of two, three, four, six and 10 scans. Likewise, analog volume measurements were made by submerging the vine trunks and cordons in water and capturing the displaced water. A regression analysis examined the relationship between digital and non-digital techniques among the 36 vines and found that the standard error drops rapidly as additional scans are added to the volume calculation process and stabilizes at the four-view geometry with an average Pearson's product moment correlation coefficient of 0.93. Estimates of digital volumes are systematically greater than those of analog volumes and can be explained by the manner in which each technique interacts with the vine tissue. This laser scanning technique yields a highly linear relationship between vine volume and tissue mass revealing a new, rapid and non-destructive method to remotely measure standing biomass. This application shows promise for use in other ecosystems such as orchards and forests. ?? 2010 Elsevier B.V.

  1. Comparison of Spine, Carina, and Tumor as Registration Landmarks for Volumetric Image-Guided Lung Radiotherapy

    SciTech Connect

    Higgins, Jane Bezjak, Andrea; Franks, Kevin; Le, Lisa W.; Cho, B.C.; Payne, David; Bissonnette, Jean-Pierre

    2009-04-01

    Purpose: To assess the feasibility, reproducibility, and accuracy of volumetric lung image guidance using different thoracic landmarks for image registration. Methods and Materials: In 30 lung patients, four independent observers conducted automated and manual image registrations on Day 1 cone-beam computed tomography data sets using the spine, carina, and tumor (720 image registrations). The image registration was timed, and the couch displacements were recorded. The intraclass correlation was used to assess reproducibility, and the Bland-Altman analysis was used to compare the automatic and manual matching methods. Tumor coverage (accuracy) was assessed through grading the tumor position after image matching against the internal target volume and planning target volume. Results: The image-guided process took an average of 1 min for all techniques, with the exception of manual tumor matching, which took 4 min. Reproducibility was greatest for automatic carina matching (intraclass correlation, 0.90-0.93) and lowest for manual tumor matching (intraclass correlation, 0.07-0.43) in the left-right, superoinferior, and anteroposterior directions, respectively. The Bland-Altman analysis showed no significant difference between the automatic and manual registration methods. The tumor was within the internal target volume 62% and 60% of the time and was outside the internal target volume, but within the planning target volume, 38% and 40% of the time after automatic spine and automatic carina matching, respectively. Conclusion: For advanced lung cancer, the spine or carina can be used equally for cone-beam computed tomography image registration without compromising target coverage. The carina was more reproducible than the spine, but additional analysis is required to confirm its validation as a tumor surrogate. Soft-tissue registration is unsuitable at present, given the limitations in contrast resolution and the high interobserver variability.

  2. 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. PMID:23292404

  3. Leucocyte cellular adhesion molecules.

    PubMed

    Yong, K; Khwaja, A

    1990-12-01

    Leucocytes express adhesion promoting receptors which mediate cell-cell and cell-matrix interactions. These adhesive interactions are crucial to the regulation of haemopoiesis and thymocyte maturation, the direction and control of leucocyte traffic and migration through tissues, and in the development of immune and non-immune inflammatory responses. Several families of adhesion receptors have been identified (Table). The leucocyte integrin family comprises 3 alpha beta heterodimeric membrane glycoproteins which share a common beta subunit, designated CD18. The alpha subunits of each of the 3 members, lymphocyte function associated antigen-1 (LFA-1), macrophage antigen-1 (Mac-1) and p150,95 are designated CD11a, b and c respectively. These adhesion molecules play a critical part in the immune and inflammatory responses of leucocytes. The leucocyte integrin family is, in turn, part of the integrin superfamily, members of which are evolutionally, structurally and functionally related. Another Integrin subfamily found on leucocytes is the VLA group, so-called because the 'very late activation antigens' VLA-1 and VLA-2 were originally found to appear late in T-cell activation. Members of this family function mainly as extracellular matrix adhesion receptors and are found both on haemopoietic and non-haemopoietic cells. They play a part in diverse cellular functions including tissue organisation, lymphocyte recirculation and T-cell immune responses. A third integrin subfamily, the cytoadhesins, are receptors on platelets and endothelial cells which bind extracellular matrix proteins. A second family of adhesion receptors is the immunoglobulin superfamily, members of which include CD2, LFA-3 and ICAM-1, which participate in T-cell adhesive interactions, and the antigen-specific receptors of T and B cells, CD4, CD8 and the MHC Class I and II molecules. A recently recognised family of adhesion receptors is the selectins, characterised by a common lectin domain. Leucocyte

  4. Single-chip CMUT-on-CMOS front-end system for real-time volumetric IVUS and ICE imaging.

    PubMed

    Gurun, Gokce; Tekes, Coskun; Zahorian, Jaime; Xu, Toby; Satir, Sarp; Karaman, Mustafa; Hasler, Jennifer; Degertekin, F Levent

    2014-02-01

    Intravascular ultrasound (IVUS) and intracardiac echography (ICE) catheters with real-time volumetric ultrasound imaging capability can provide unique benefits to many interventional procedures used in the diagnosis and treatment of coronary and structural heart diseases. Integration of capacitive micromachined ultrasonic transducer (CMUT) arrays with front-end electronics in single-chip configuration allows for implementation of such catheter probes with reduced interconnect complexity, miniaturization, and high mechanical flexibility. We implemented a single-chip forward-looking (FL) ultrasound imaging system by fabricating a 1.4-mm-diameter dual-ring CMUT array using CMUT-on-CMOS technology on a front-end IC implemented in 0.35-μm CMOS process. The dual-ring array has 56 transmit elements and 48 receive elements on two separate concentric annular rings. The IC incorporates a 25-V pulser for each transmitter and a low-noise capacitive transimpedance amplifier (TIA) for each receiver, along with digital control and smart power management. The final shape of the silicon chip is a 1.5-mm-diameter donut with a 430-μm center hole for a guide wire. The overall front-end system requires only 13 external connections and provides 4 parallel RF outputs while consuming an average power of 20 mW. We measured RF A-scans from the integrated single- chip array which show full functionality at 20.1 MHz with 43% fractional bandwidth. We also tested and demonstrated the image quality of the system on a wire phantom and an ex vivo chicken heart sample. The measured axial and lateral point resolutions are 92 μm and 251 μm, respectively. We successfully acquired volumetric imaging data from the ex vivo chicken heart at 60 frames per second without any signal averaging. These demonstrative results indicate that single-chip CMUT-on-CMOS systems have the potential to produce realtime volumetric images with image quality and speed suitable for catheter-based clinical applications

  5. Accuracy of 3D volumetric image registration based on CT, MR and PET/CT phantom experiments.

    PubMed

    Li, Guang; Xie, Huchen; Ning, Holly; Citrin, Deborah; Capala, Jacek; Maass-Moreno, Roberto; Guion, Peter; Arora, Barbara; Coleman, Norman; Camphausen, Kevin; Miller, Robert W

    2008-01-01

    Registration is critical for image-based treatment planning and image-guided treatment delivery. Although automatic registration is available, manual, visual-based image fusion using three orthogonal planar views (3P) is always employed clinically to verify and adjust an automatic registration result. However, the 3P fusion can be time consuming, observer dependent, as well as prone to errors, owing to the incomplete 3-dimensional (3D) volumetric image representations. It is also limited to single-pixel precision (the screen resolution). The 3D volumetric image registration (3DVIR) technique was developed to overcome these shortcomings. This technique introduces a 4th dimension in the registration criteria beyond the image volume, offering both visual and quantitative correlation of corresponding anatomic landmarks within the two registration images, facilitating a volumetric image alignment, and minimizing potential registration errors. The 3DVIR combines image classification in real-time to select and visualize a reliable anatomic landmark, rather than using all voxels for alignment. To determine the detection limit of the visual and quantitative 3DVIR criteria, slightly misaligned images were simulated and presented to eight clinical personnel for interpretation. Both of the criteria produce a detection limit of 0.1 mm and 0.1 degree. To determine the accuracy of the 3DVIR method, three imaging modalities (CT, MR and PET/CT) were used to acquire multiple phantom images with known spatial shifts. Lateral shifts were applied to these phantoms with displacement intervals of 5.0+/-0.1 mm. The accuracy of the 3DVIR technique was determined by comparing the image shifts determined through registration to the physical shifts made experimentally. The registration accuracy, together with precision, was found to be: 0.02+/-0.09 mm for CT/CT images, 0.03+/-0.07 mm for MR/MR images, and 0.03+/-0.35 mm for PET/CT images. This accuracy is consistent with the detection limit

  6. On Utilization of NEXRAD Scan Strategy Information to Infer Discrepancies Associated With Radar and Rain Gauge Surface Volumetric Rainfall Accumulations

    NASA Technical Reports Server (NTRS)

    Roy, Biswadev; Datta, Saswati; Jones, W. Linwood; Kasparis, Takis; Einaudi, Franco (Technical Monitor)

    2000-01-01

    To evaluate the Tropical Rainfall Measuring Mission (TRMM) monthly Ground Validation (GV) rain map, 42 quality controlled tipping bucket rain gauge data (1 minute interpolated rain rates) were utilized. We have compared the gauge data to the surface volumetric rainfall accumulation of NEXRAD reflectivity field, (converting to rain rates using a 0.5 dB resolution smooth Z-R table). The comparison was carried out from data collected at Melbourne, Florida during the month of July 98. GV operational level 3 (L3 monthly) accumulation algorithm was used to obtain surface volumetric accumulations for the radar. The gauge records were accumulated using the 1 minute interpolated rain rates while the radar Volume Scan (VOS) intervals remain less than or equal to 75 minutes. The correlation coefficient for the radar and gauge totals for the monthly time-scale remain at 0.93, however, a large difference was noted between the gauge and radar derived rain accumulation when the radar data interval is either 9 minute, or 10 minute. This difference in radar and gauge accumulation is being explained in terms of the radar scan strategy information. The discrepancy in terms of the Volume Coverage Pattern (VCP) of the NEXRAD is being reported where VCP mode is ascertained using the radar tilt angle information. Hourly radar and gauge accumulations have been computed using the present operational L3 method supplemented with a threshold period of +/- 5 minutes (based on a sensitivity analysis). These radar and gauge accumulations are subsequently improved using a radar hourly scan weighting factor (taking ratio of the radar scan frequency within a time bin to the 7436 total radar scans for the month). This GV procedure is further being improved by introducing a spatial smoothing method to yield reasonable bulk radar to gauge ratio for the hourly and daily scales.

  7. On the resolution of plenoptic PIV

    NASA Astrophysics Data System (ADS)

    Deem, Eric A.; Zhang, Yang; Cattafesta, Louis N.; Fahringer, Timothy W.; Thurow, Brian S.

    2016-08-01

    Plenoptic PIV offers a simple, single camera solution for volumetric velocity measurements of fluid flow. However, due to the novel manner in which the particle images are acquired and processed, few references exist to aid in determining the resolution limits of the measurements. This manuscript provides a framework for determining the spatial resolution of plenoptic PIV based on camera design and experimental parameters. This information can then be used to determine the smallest length scales of flows that are observable by plenoptic PIV, the dynamic range of plenoptic PIV, and the corresponding uncertainty in plenoptic PIV measurements. A simplified plenoptic camera is illustrated to provide the reader with a working knowledge of the method in which the light field is recorded. Then, operational considerations are addressed. This includes a derivation of the depth resolution in terms of the design parameters of the camera. Simulated volume reconstructions are presented to validate the derived limits. It is found that, while determining the lateral resolution is relatively straightforward, many factors affect the resolution along the optical axis. These factors are addressed and suggestions are proposed for improving performance.

  8. Golden-Angle Radial Sparse Parallel MRI: Combination of Compressed Sensing, Parallel Imaging, and Golden-Angle Radial Sampling for Fast and Flexible Dynamic Volumetric MRI

    PubMed Central

    Feng, Li; Grimm, Robert; Block, Kai Tobias; Chandarana, Hersh; Kim, Sungheon; Xu, Jian; Axel, Leon; Sodickson, Daniel K.; Otazo, Ricardo

    2013-01-01

    Purpose To develop a fast and flexible free-breathing dynamic volumetric MRI technique, iterative Golden-angle RAdial Sparse Parallel MRI (iGRASP), that combines compressed sensing, parallel imaging, and golden-angle radial sampling. Methods Radial k-space data are acquired continuously using the golden-angle scheme and sorted into time series by grouping an arbitrary number of consecutive spokes into temporal frames. An iterative reconstruction procedure is then performed on the undersampled time series where joint multicoil sparsity is enforced by applying a total-variation constraint along the temporal dimension. Required coil-sensitivity profiles are obtained from the time-averaged data. Results iGRASP achieved higher acceleration capability than either parallel imaging or coil-by-coil compressed sensing alone. It enabled dynamic volumetric imaging with high spatial and temporal resolution for various clinical applications, including free-breathing dynamic contrast-enhanced imaging in the abdomen of both adult and pediatric patients, and in the breast and neck of adult patients. Conclusion The high performance and flexibility provided by iGRASP can improve clinical studies that require robustness to motion and simultaneous high spatial and temporal resolution. PMID:24142845

  9. A Comparison of Substantia Nigra T1 Hyperintensity in Parkinson's Disease Dementia, Alzheimer's Disease and Age-Matched Controls: Volumetric Analysis of Neuromelanin Imaging

    PubMed Central

    Park, Ju-Yeon; Yun, Won-Sung; Jeon, Ji Yeong; Moon, Yeon Sil; Kim, Heejin; Kwak, Ki-Chang; Lee, Jong-Min; Han, Seol-Heui

    2016-01-01

    Objective Neuromelanin loss of substantia nigra (SN) can be visualized as a T1 signal reduction on T1-weighted high-resolution imaging. We investigated whether volumetric analysis of T1 hyperintensity for SN could be used to differentiate between Parkinson's disease dementia (PDD), Alzheimer's disease (AD) and age-matched controls. Materials and Methods This retrospective study enrolled 10 patients with PDD, 18 patients with AD, and 13 age-matched healthy elderly controls. MR imaging was performed at 3 tesla. To measure the T1 hyperintense area of SN, we obtained an axial thin section high-resolution T1-weighted fast spin echo sequence. The volumes of interest for the T1 hyperintense SN were drawn onto heavily T1-weighted FSE sequences through midbrain level, using the MIPAV software. The measurement differences were tested using the Kruskal-Wallis test followed by a post hoc comparison. Results A comparison of the three groups showed significant differences in terms of volume of T1 hyperintensity (p < 0.001, Bonferroni corrected). The volume of T1 hyperintensity was significantly lower in PDD than in AD and normal controls (p < 0.005, Bonferroni corrected). However, the volume of T1 hyperintensity was not different between AD and normal controls (p = 0.136, Bonferroni corrected). Conclusion The volumetric measurement of the T1 hyperintensity of SN can be an imaging marker for evaluating neuromelanin loss in neurodegenerative diseases and a differential in PDD and AD cases. PMID:27587951

  10. Total Marrow Irradiation With RapidArc Volumetric Arc Therapy

    SciTech Connect

    Aydogan, Bulent; Yeginer, Mete; Kavak, Gulbin O.; Fan, John; Radosevich, James A.; Gwe-Ya, Kim

    2011-10-01

    Purpose: To develop a volumetric arc therapy (VMAT)-total marrow irradiation (TMI) technique for patients with hematologic malignancies. Methods and Materials: VMAT planning was performed for 6 patients using RapidArc technology. The planning target volume consisted of all the bones in the body from the head to the mid-femur, excluding the extremities, except for the humerus, plus a 3.0-mm margin. The organs at risk included the lungs, heart, liver, kidneys, bowels, brain, eyes, and oral cavity. The VMAT-TMI technique consisted of three plans: the head and neck, the chest, and the pelvis, each with three 330{sup o} arcs. The plans were prescribed to ensure, at a minimum, 95% planning target volume dose coverage with the prescription dose (percentage of volume receiving dose of {>=}12 Gy was 95%). The treatments were delivered and verified using MapCheck and ion chamber measurements. Results: The VMAT-TMI technique reported in the present study provided comparable dose distributions with respect to the fixed gantry linear accelerator intensity-modulated TMI. RapidArc planning was less subjective and easier, and, most importantly, the delivery was more efficient. RapidArc reduced the treatment delivery time to approximately 18 min from 45 min with the fixed gantry linear accelerator intensity-modulated TMI. When the prescription dose coverage was reduced to 85% from 95% and the mandible and maxillary structures were not included in the planning target volume as reported in a tomotherapy study, a considerable organ at risk dose reduction of 4.2-51% was observed. The average median dose for the lungs and lenses was reduced to 5.6 Gy from 7.2 Gy and 2.4 Gy from 4.5 Gy, respectively. Conclusion: The RapidArc VMAT technique improved the treatment planning, dose conformality, and, most importantly, treatment delivery efficiency. The results from our study suggest that the RapidArc VMAT technology can be expected to facilitate the clinical transition of TMI.

  11. Choreographing Couch and Collimator in Volumetric Modulated Arc Therapy

    SciTech Connect

    Yang Yingli; Zhang Pengpeng; Happersett, Laura; Xiong Jianping; Yang Jie; Chan, Maria; Beal, Kathryn; Mageras, Gig; Hunt, Margie

    2011-07-15

    Purpose: To design and optimize trajectory-based, noncoplanar subarcs for volumetric modulated arc therapy (VMAT) deliverable on both Varian TrueBEAM system and traditional accelerators; and to investigate their potential advantages for treating central nervous system (CNS) tumors. Methods and Materials: To guide the computerized selection of beam trajectories consisting of simultaneous couch, gantry, and collimator motion, a score function was implemented to estimate the geometric overlap between targets and organs at risk for each couch/gantry angle combination. An initial set of beam orientations is obtained as a function of couch and gantry angle, according to a minimum search of the score function excluding zones of collision. This set is grouped into multiple continuous and extended subarcs subject to mechanical limitations using a hierarchical clustering algorithm. After determination of couch/gantry trajectories, a principal component analysis finds the collimator angle at each beam orientation that minimizes residual target-organ at risk overlaps. An in-house VMAT optimization algorithm determines the optimal multileaf collimator position and monitor units for control points within each subarc. A retrospective study of 10 CNS patients compares the proposed method of VMAT trajectory with dynamic gantry, leaves, couch, and collimator motion (Tra-VMAT); a standard noncoplanar VMAT with no couch/collimator motion within subarcs (Std-VMAT); and noncoplanar intensity-modulated radiotherapy (IMRT) plans that were clinically used. Results: Tra-VMAT provided improved target dose conformality and lowered maximum dose to brainstem, optic nerves, and chiasm by 7.7%, 1.1%, 2.3%, and 1.7%, respectively, compared with Std-VMAT. Tra-VMAT provided higher planning target volume minimum dose and reduced maximum dose to chiasm, optic nerves, and cochlea by 6.2%, 1.3%, 6.3%, and 8.4%, respectively, and reduced cochlea mean dose by 8.7%, compared with IMRT. Tra-VMAT averaged

  12. Three-dimensional volumetric quantification of fat loss following cryolipolysis

    PubMed Central

    Garibyan, Lilit; Sipprell, William H; Jalian, H. Ray; Sakamoto, Fernanda H.; Avram, Mathew; Anderson, R. Rox

    2014-01-01

    Background and Objectives Cryolipolysis is a noninvasive and well-tolerated treatment for reduction of localized subcutaneous fat. Although several studies demonstrate the safety and efficacy of this procedure, volumetric fat reduction from this treatment has not been quantified. This prospective study investigated the change in volume of fat after cryolipolysis treatment using three-dimensional (3D) photography. Materials and Methods A prospective study of subjects treated with cryolipolysis on the flank (love handle) was performed at Massachusetts General Hospital. Volume measurements were performed with a Canfield Scientific Vectra three-dimensional camera and software to evaluate the amount of post procedure volume change. Clinical outcomes were assessed with caliper measurements, subject surveys, and blinded physician assessment of photographs. Results Eleven subjects were enrolled in this study. Each subject underwent a single cycle of cryolipolysis to one flank. The untreated flank served as an internal control. The follow up time after treatment was two months. The mean amount of calculated absolute fat volume loss using 3D photography from baseline to 2 months follow up visit was 56.2 ± 25.6 from the treatment site and 16.6 ± 17.6 cc from the control (p < 0.0001). A mean absolute difference of 39.6 cc between the treated and untreated sides was calculated at 2 months post-treatment. Comparison of caliper measurements from baseline to 2 months post-treatment demonstrated significant reduction of the treated flank from 45.6 ± 5.8 mm at baseline to 38.6 ±4.6 mm at 2 months post-treatment (p<0.001). The untreated flank did not show significant reduction with caliper measurements demonstrating 45.3 ± 5.0 mm at baseline and 44.6 ± 5.1 mm at 2 months post-treatment (p=0.360). No unexpected side effects or adverse events were reported. Post-treatment satisfaction surveys demonstrated 82% of subjects were satisfied with the results. Conclusions Cryolipolysis

  13. Long-Term Volumetric Eruption Rates and Magma Budgets

    SciTech Connect

    Scott M. White Dept. Geological Sciences University of South Carolina Columbia, SC 29208; Joy A. Crisp Jet Propulsion Laboratory, California Institute of Technology Pasadena, CA 91109; Frank J. Spera Dept. Earth Science University of California, Santa Barbara Santa Barbara, CA 93106

    2005-01-01

    A global compilation of 170 time-averaged volumetric volcanic output rates (Qe) is evaluated in terms of composition and petrotectonic setting to advance the understanding of long-term rates of magma generation and eruption on Earth. Repose periods between successive eruptions at a given site and intrusive:extrusive ratios were compiled for selected volcanic centers where long-term (>104 years) data were available. More silicic compositions, rhyolites and andesites, have a more limited range of eruption rates than basalts. Even when high Qe values contributed by flood basalts (9 ± 2 Å~ 10-1 km3/yr) are removed, there is a trend in decreasing average Qe with lava composition from basaltic eruptions (2.6 ± 1.0 Å~ 10-2 km3/yr) to andesites (2.3 ± 0.8 Å~ 10-3 km3/yr) and rhyolites (4.0 ± 1.4 Å~ 10-3 km3/yr). This trend is also seen in the difference between oceanic and continental settings, as eruptions on oceanic crust tend to be predominately basaltic. All of the volcanoes occurring in oceanic settings fail to have statistically different mean Qe and have an overall average of 2.8 ± 0.4 Å~ 10-2 km3/yr, excluding flood basalts. Likewise, all of the volcanoes on continental crust also fail to have statistically different mean Qe and have an overall average of 4.4 ± 0.8 Å~ 10-3 km3/yr. Flood basalts also form a distinctive class with an average Qe nearly two orders of magnitude higher than any other class. However, we have found no systematic evidence linking increased intrusive:extrusive ratios with lower volcanic rates. A simple heat balance analysis suggests that the preponderance of volcanic systems must be open magmatic systems with respect to heat and matter transport in order to maintain eruptible magma at shallow depth throughout the observed lifetime of the volcano. The empirical upper limit of Å`10-2 km3/yr for magma eruption rate in systems with relatively high intrusive:extrusive ratios may be a consequence of the fundamental parameters

  14. Measurement-guided volumetric dose reconstruction for helical tomotherapy.

    PubMed

    Stambaugh, Cassandra; Nelms, Benjamin; Wolf, Theresa; Mueller, Richard; Geurts, Mark; Opp, Daniel; Moros, Eduardo; Zhang, Geoffrey; Feygelman, Vladimir

    2015-01-01

    12% (2% G/2). We conclude that TPDP is capable of volumetric dose reconstruction with acceptable accuracy. However, the challenges of fast tomotherapy delivery dynamics make TPDP less precise than the IMRT/VMAT PDP version, particularly for the 1 cm jaw setting. PMID:26103199

  15. Volumetric capnography for the evaluation of chronic airways diseases

    PubMed Central

    Veronez, Liliani; Pereira, Monica Corso; Doria da Silva, Silvia Maria; Barcaui, Luisa Affi; De Capitani, Eduardo Mello; Moreira, Marcos Mello; Paschoal, Ilma Aparecida

    2014-01-01

    Background Obstructive lung diseases of different etiologies present with progressive peripheral airway involvement. The peripheral airways, known as the silent lung zone, are not adequately evaluated with conventional function tests. The principle of gas washout has been used to detect pulmonary ventilation inhomogeneity and to estimate the location of the underlying disease process. Volumetric capnography (VC) analyzes the pattern of CO2 elimination as a function of expired volume. Objective To measure normalized phase 3 slopes with VC in patients with non-cystic fibrosis bronchiectasis (NCB) and in bronchitic patients with chronic obstructive pulmonary disease (COPD) in order to compare the slopes obtained for the groups. Methods NCB and severe COPD were enrolled sequentially from an outpatient clinic (Hospital of the State University of Campinas). A control group was established for the NCB group, paired by sex and age. All subjects performed spirometry, VC, and the 6-Minute Walk Test (6MWT). Two comparisons were made: NCB group versus its control group, and NCB group versus COPD group. The project was approved by the ethical committee of the institution. Statistical tests used were Wilcoxon or Student’s t-test; P<0.05 was considered to be a statistically significant difference. Results Concerning the NCB group (N=20) versus the control group (N=20), significant differences were found in body mass index and in several functional variables (spirometric, VC, 6MWT) with worse results observed in the NCB group. In the comparison between the COPD group (N=20) versus the NCB group, although patients with COPD had worse spirometric and 6MWT values, the capnographic variables mean phase 2 slope (Slp2), mean phase 3 slope normalized by the mean expiratory volume, or mean phase 3 slope normalized by the end-tidal CO2 concentration were similar. Conclusion These findings may indicate that the gas elimination curves are not sensitive enough to monitor the severity of

  16. Dose verification for respiratory-gated volumetric modulated arc therapy

    NASA Astrophysics Data System (ADS)

    Qian, Jianguo; Xing, Lei; Liu, Wu; Luxton, Gary

    2011-08-01

    A novel commercial medical linac system (TrueBeam™, Varian Medical Systems, Palo Alto, CA) allows respiratory-gated volumetric modulated arc therapy (VMAT), a new modality for treating moving tumors with high precision and improved accuracy by allowing for regular motion associated with a patient's breathing during VMAT delivery. The purpose of this work is to adapt a previously-developed dose reconstruction technique to evaluate the fidelity of VMAT treatment during gated delivery under clinic-relevant periodic motion related to patient breathing. A Varian TrueBeam system was used in this study. VMAT plans were created for three patients with lung or pancreas tumors. Conventional 6 and 15 MV beams with flattening filter and high-dose-rate 10 MV beams with no flattening filter were used in these plans. Each patient plan was delivered to a phantom first without gating and then with gating for three simulated respiratory periods (3, 4.5 and 6 s). Using the adapted log-file-based dose reconstruction procedure supplemented with ion chamber array (Seven29™, PTW, Freiburg, Germany) measurements, the delivered dose was used to evaluate the fidelity of gated VMAT delivery. Comparison of Seven29 measurements with and without gating showed good agreement with gamma-index passing rates above 99% for 1%/1 mm dose accuracy/distance-to-agreement criteria. With original plans as reference, gamma-index passing rates were 100% for the reconstituted plans (1%/1 mm criteria) and 93.5-100% for gated Seven29 measurements (3%/3 mm criteria). In the presence of leaf error deliberately introduced into the gated delivery of a pancreas patient plan, both dose reconstruction and Seven29 measurement consistently indicated substantial dosimetric differences from the original plan. In summary, a dose reconstruction procedure was demonstrated for evaluating the accuracy of respiratory-gated VMAT delivery. This technique showed that under clinical operation, the TrueBeam system faithfully

  17. Robust Radiomics Feature Quantification Using Semiautomatic Volumetric Segmentation

    PubMed Central

    Leijenaar, Ralph; Jermoumi, Mohammed; Carvalho, Sara; Mak, Raymond H.; Mitra, Sushmita; Shankar, B. Uma; Kikinis, Ron; Haibe-Kains, Benjamin; Lambin, Philippe; Aerts, Hugo J. W. L.

    2014-01-01

    Due to advances in the acquisition and analysis of medical imaging, it is currently possible to quantify the tumor phenotype. The emerging field of Radiomics addresses this issue by converting medical images into minable data by extracting a large number of quantitative imaging features. One of the main challenges of Radiomics is tumor segmentation. Where manual delineation is time consuming and prone to inter-observer variability, it has been shown that semi-automated approaches are fast and reduce inter-observer variability. In this study, a semiautomatic region growing volumetric segmentation algorithm, implemented in the free and publicly available 3D-Slicer platform, was investigated in terms of its robustness for quantitative imaging feature extraction. Fifty-six 3D-radiomic features, quantifying phenotypic differences based on tumor intensity, shape and texture, were extracted from the computed tomography images of twenty lung cancer patients. These radiomic features were derived from the 3D-tumor volumes defined by three independent observers twice using 3D-Slicer, and compared to manual slice-by-slice delineations of five independent physicians in terms of intra-class correlation coefficient (ICC) and feature range. Radiomic features extracted from 3D-Slicer segmentations had significantly higher reproducibility (ICC = 0.85±0.15, p = 0.0009) compared to the features extracted from the manual segmentations (ICC = 0.77±0.17). Furthermore, we found that features extracted from 3D-Slicer segmentations were more robust, as the range was significantly smaller across observers (p = 3.819e-07), and overlapping with the feature ranges extracted from manual contouring (boundary lower: p = 0.007, higher: p = 5.863e-06). Our results show that 3D-Slicer segmented tumor volumes provide a better alternative to the manual delineation for feature quantification, as they yield more reproducible imaging descriptors. Therefore, 3D-Slicer can be

  18. Robust Radiomics feature quantification using semiautomatic volumetric segmentation.

    PubMed

    Parmar, Chintan; Rios Velazquez, Emmanuel; Leijenaar, Ralph; Jermoumi, Mohammed; Carvalho, Sara; Mak, Raymond H; Mitra, Sushmita; Shankar, B Uma; Kikinis, Ron; Haibe-Kains, Benjamin; Lambin, Philippe; Aerts, Hugo J W L

    2014-01-01

    Due to advances in the acquisition and analysis of medical imaging, it is currently possible to quantify the tumor phenotype. The emerging field of Radiomics addresses this issue by converting medical images into minable data by extracting a large number of quantitative imaging features. One of the main challenges of Radiomics is tumor segmentation. Where manual delineation is time consuming and prone to inter-observer variability, it has been shown that semi-automated approaches are fast and reduce inter-observer variability. In this study, a semiautomatic region growing volumetric segmentation algorithm, implemented in the free and publicly available 3D-Slicer platform, was investigated in terms of its robustness for quantitative imaging feature extraction. Fifty-six 3D-radiomic features, quantifying phenotypic differences based on tumor intensity, shape and texture, were extracted from the computed tomography images of twenty lung cancer patients. These radiomic features were derived from the 3D-tumor volumes defined by three independent observers twice using 3D-Slicer, and compared to manual slice-by-slice delineations of five independent physicians in terms of intra-class correlation coefficient (ICC) and feature range. Radiomic features extracted from 3D-Slicer segmentations had significantly higher reproducibility (ICC = 0.85±0.15, p = 0.0009) compared to the features extracted from the manual segmentations (ICC = 0.77±0.17). Furthermore, we found that features extracted from 3D-Slicer segmentations were more robust, as the range was significantly smaller across observers (p = 3.819e-07), and overlapping with the feature ranges extracted from manual contouring (boundary lower: p = 0.007, higher: p = 5.863e-06). Our results show that 3D-Slicer segmented tumor volumes provide a better alternative to the manual delineation for feature quantification, as they yield more reproducible imaging descriptors. Therefore, 3D-Slicer can be

  19. Bone lead (Pb) content at the tibia is associated with thinner distal tibia cortices and lower volumetric bone density in postmenopausal women.

    PubMed

    Wong, Andy K O; Beattie, Karen A; Bhargava, Aakash; Cheung, Marco; Webber, Colin E; Chettle, David R; Papaioannou, Alexandra; Adachi, Jonathan D

    2015-10-01

    Conflicting evidence suggests that bone lead or blood lead may reduce areal bone mineral density (BMD). Little is known about how lead at either compartment affects bone structure. This study examined postmenopausal women (N=38, mean age 76 ± 8, body mass index (BMI): 26.74 ± 4.26 kg/m(2)) within the Hamilton cohort of the Canadian Multicentre Osteoporosis Study (CaMos), measuring bone lead at 66% of the non-dominant leg and at the calcaneus using (109)Cadmium X-ray fluorescence. Volumetric BMD and structural parameters were obtained from peripheral quantitative computed tomography images (200 μm in-plane resolution, 2.3 ± 0.5mm slice thickness) of the same 66% site and of the distal 4% site of the tibia length. Blood lead was measured using atomic absorption spectrometry and blood-to-bone lead partition coefficients (PBB, log ratio) were computed. Multivariable linear regression examined each of bone lead at the 66% tibia, calcaneus, blood lead and PBB as related to each of volumetric BMD and structural parameters, adjusting for age and BMI, diabetes or antiresorptive therapy. Regression coefficients were reported along with 95% confidence intervals. Higher amounts of bone lead at the tibia were associated with thinner distal tibia cortices (-0.972 (-1.882, -0.061) per 100 μg Pb/g of bone mineral) and integral volumetric BMD (-3.05 (-6.05, -0.05) per μg Pb/g of bone mineral). A higher PBB was associated with larger trabecular separation (0.115 (0.053, 0.178)), lower trabecular volumetric BMD (-26.83 (-50.37, -3.29)) and trabecular number (-0.08 (-0.14, -0.02)), per 100 μg Pb/g of bone mineral after adjusting for age and BMI, and remained significant while accounting for diabetes or use of antiresorptives. Total lead exposure activities related to bone lead at the calcaneus (8.29 (0.11, 16.48)) and remained significant after age and antiresorptives-adjustment. Lead accumulated in bone can have a mild insult on bone structure; but greater partitioning of lead

  20. A three-dimensional-weighted cone beam filtered backprojection (CB-FBP) algorithm for image reconstruction in volumetric CT-helical scanning.

    PubMed

    Tang, Xiangyang; Hsieh, Jiang; Nilsen, Roy A; Dutta, Sandeep; Samsonov, Dmitry; Hagiwara, Akira

    2006-02-21

    Based on the structure of the original helical FDK algorithm, a three-dimensional (3D)-weighted cone beam filtered backprojection (CB-FBP) algorithm is proposed for image reconstruction in volumetric CT under helical source trajectory. In addition to its dependence on view and fan angles, the 3D weighting utilizes the cone angle dependency of a ray to improve reconstruction accuracy. The 3D weighting is ray-dependent and the underlying mechanism is to give a favourable weight to the ray with the smaller cone angle out of a pair of conjugate rays but an unfavourable weight to the ray with the larger cone angle out of the conjugate ray pair. The proposed 3D-weighted helical CB-FBP reconstruction algorithm is implemented in the cone-parallel geometry that can improve noise uniformity and image generation speed significantly. Under the cone-parallel geometry, the filtering is naturally carried out along the tangential direction of the helical source trajectory. By exploring the 3D weighting's dependence on cone angle, the proposed helical 3D-weighted CB-FBP reconstruction algorithm can provide significantly improved reconstruction accuracy at moderate cone angle and high helical pitches. The 3D-weighted CB-FBP algorithm is experimentally evaluated by computer-simulated phantoms and phantoms scanned by a diagnostic volumetric CT system with a detector dimension of 64 x 0.625 mm over various helical pitches. The computer simulation study shows that the 3D weighting enables the proposed algorithm to reach reconstruction accuracy comparable to that of exact CB reconstruction algorithms, such as the Katsevich algorithm, under a moderate cone angle (4 degrees) and various helical pitches. Meanwhile, the experimental evaluation using the phantoms scanned by a volumetric CT system shows that the spatial resolution along the z-direction and noise characteristics of the proposed 3D-weighted helical CB-FBP reconstruction algorithm are maintained very well in comparison to the FDK

  1. A three-dimensional-weighted cone beam filtered backprojection (CB-FBP) algorithm for image reconstruction in volumetric CT—helical scanning

    NASA Astrophysics Data System (ADS)

    Tang, Xiangyang; Hsieh, Jiang; Nilsen, Roy A.; Dutta, Sandeep; Samsonov, Dmitry; Hagiwara, Akira

    2006-02-01

    Based on the structure of the original helical FDK algorithm, a three-dimensional (3D)-weighted cone beam filtered backprojection (CB-FBP) algorithm is proposed for image reconstruction in volumetric CT under helical source trajectory. In addition to its dependence on view and fan angles, the 3D weighting utilizes the cone angle dependency of a ray to improve reconstruction accuracy. The 3D weighting is ray-dependent and the underlying mechanism is to give a favourable weight to the ray with the smaller cone angle out of a pair of conjugate rays but an unfavourable weight to the ray with the larger cone angle out of the conjugate ray pair. The proposed 3D-weighted helical CB-FBP reconstruction algorithm is implemented in the cone-parallel geometry that can improve noise uniformity and image generation speed significantly. Under the cone-parallel geometry, the filtering is naturally carried out along the tangential direction of the helical source trajectory. By exploring the 3D weighting's dependence on cone angle, the proposed helical 3D-weighted CB-FBP reconstruction algorithm can provide significantly improved reconstruction accuracy at moderate cone angle and high helical pitches. The 3D-weighted CB-FBP algorithm is experimentally evaluated by computer-simulated phantoms and phantoms scanned by a diagnostic volumetric CT system with a detector dimension of 64 × 0.625 mm over various helical pitches. The computer simulation study shows that the 3D weighting enables the proposed algorithm to reach reconstruction accuracy comparable to that of exact CB reconstruction algorithms, such as the Katsevich algorithm, under a moderate cone angle (4°) and various helical pitches. Meanwhile, the experimental evaluation using the phantoms scanned by a volumetric CT system shows that the spatial resolution along the z-direction and noise characteristics of the proposed 3D-weighted helical CB-FBP reconstruction algorithm are maintained very well in comparison to the FDK

  2. Cellular compartmentalization of secondary metabolism

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fungal secondary metabolism is often considered apart from the essential housekeeping functions of the cell. However, there are clear links between fundamental cellular metabolism and the biochemical pathways leading to secondary metabolite synthesis. Besides utilizing key biochemical precursors sh...

  3. Cellular therapy for haematological malignancies.

    PubMed

    Roddie, P H; Turner, M L

    2002-11-01

    The aim of this review was to summarize the recent progress made in the field of cellular therapeutics in haematological malignancy. The review also examined the role that the National Transfusion Services might play in the manufacture of new cellular therapeutic agents, given both their expertise in the safe provision of blood products and their possession of accredited cell manipulation facilities. Cellular therapy is entering an era in which novel cellular products will find increasing clinical use, particularly in the areas of haematopoietic stem cell transplantation and immunotherapy. The production of novel cell-based therapies, both in Europe and North America, is now under strict regulatory control and therefore collaboration with the National Transfusion Services in the manufacture of these agents may well be beneficial if the production standards demanded by the regulatory authorities are to be fulfilled. PMID:12437515

  4. Mathematical Modeling of Cellular Metabolism.

    PubMed

    Berndt, Nikolaus; Holzhütter, Hermann-Georg

    2016-01-01

    Cellular metabolism basically consists of the conversion of chemical compounds taken up from the extracellular environment into energy (conserved in energy-rich bonds of organic phosphates) and a wide array of organic molecules serving as catalysts (enzymes), information carriers (nucleic acids), and building blocks for cellular structures such as membranes or ribosomes. Metabolic modeling aims at the construction of mathematical representations of the cellular metabolism that can be used to calculate the concentration of cellular molecules and the rates of their mutual chemical interconversion in response to varying external conditions as, for example, hormonal stimuli or supply of essential nutrients. Based on such calculations, it is possible to quantify complex cellular functions as cellular growth, detoxification of drugs and xenobiotic compounds or synthesis of exported molecules. Depending on the specific questions to metabolism addressed, the methodological expertise of the researcher, and available experimental information, different conceptual frameworks have been established, allowing the usage of computational methods to condense experimental information from various layers of organization into (self-) consistent models. Here, we briefly outline the main conceptual frameworks that are currently exploited in metabolism research. PMID:27557541

  5. Natural resolution of inflammation.

    PubMed

    Freire, Marcelo O; Van Dyke, Thomas E

    2013-10-01

    Inflammation is a protective response essential for maintaining human health and for fighting disease. As an active innate immune reaction to challenge, inflammation gives rise to clinical cardinal signs: rubor, calor, dolor, tumor and functio laesa. Termination of acute inflammation was previously recognized as a passive process; a natural decay of pro-inflammatory signals. We now understand that the natural resolution of inflammation involves well-integrated, active, biochemical programs that return tissues to homeostasis. This review focuses on recent advances in the understanding of the role of endogenous lipid mediators that modulate cellular fate and inflammation. Biosynthesis of eicosanoids and other lipids in exudates coincides with changes in the types of inflammatory cells. Resolution of inflammation is initiated by an active class switch in lipid mediators, such as classic prostaglandins and leukotrienes, to the production of proresolution mediators. Endogenous pro-resolving lipid mediators, including arachidonic acid-derived lipoxins, aspirin-triggered lipoxins, ω3-eicosapentaenoic acid-derived resolvins of the E-series, docosahexaenoic acid-derived resolvins of the D-series, protectins and maresins, are biosynthesized during the resolution phase of acute inflammation. Depending on the type of injury and the type of tissue, the initial cells that respond are polymorphonuclear leukocytes, monocytes/macrophages, epithelial cells or endothelial cells. The selective interaction of specific lipid mediators with G protein-coupled receptors expressed on innate immune cells (e.g. G protein-coupled receptor 32, lipoxin A4 receptor/formyl peptide receptor2, chemokine-like receptor 1, leukotriene B4 receptor type 1 and cabannoid receptor 2) induces cessation of leukocyte infiltration; vascular permeability/edema returns to normal with polymorphonuclear neutrophil death (mostly via apoptosis), the nonphlogistic infiltration of monocyte/macrophages and the removal

  6. Volumetric thermoacoustic imaging over large fields of view.

    PubMed

    Roggenbuck, M A; Walker, R D; Catenacci, J W; Patch, S K

    2013-01-01

    The thermoacoustic (TA) contrast mechanism relies on rapid tissue heating and subsequent thermal expansion. TA computerized tomography (TCT) is therefore inverse source imaging. The TA contrast mechanism provides information complementary to that revealed by current diagnostic imaging techniques, but has been limited to just a few centimeters depth penetration. In this article, whole organ TCT is demonstrated on a large swine kidney. TA sinograms show that TA signal generated by high-power, very high frequency (VHF) electromagnetic pulses is detectable after travel through 6 cm of soft tissue. Reconstructed images provide resolution sufficient to track progression of calyces throughout the kidney. Because VHF electromagnetic energy can easily penetrate the abdomen of large adults, our results indicate that whole organ TA imaging is feasible in vivo, provided an ultrasound array can be placed near the region of interest. Pulses of 22 to 25 kW with carrier frequency 108 MHz and 900 ns pulse width were applied at a 100-Hz pulse repetition frequency to generate a 13-kV/m electric field and TA signal. Only 2 to 5 mJ was absorbed in the kidney per pulse, causing temperature and pressure jumps of only 5e-6°C and 4 Pa averaged throughout the 141-g specimen. TA pulses were detected by focused, single-element transducers (V306, Panametrics), amplified by 54 dB and averaged 64 times to reduce electronic noise. Data were measured over a cylindrical measurement aperture of radius 5 cm and length 6 cm, by rotating the specimen 1.8 degrees between tomographic views and translating 2 mm between slices. Reconstruction via filtered backprojection yields in-plane resolution better than 5 mm, but suffers significant blurring between planes. Both in-plane resolution and slice sensitivity profile could be improved by applying shorter irradiation pulsewidths and using less directional transducers. Both hardware changes would be recommended for a clinical prototype. PMID:23287507

  7. Modeling cloth at micron resolution

    NASA Astrophysics Data System (ADS)

    Bala, Kavita

    2014-02-01

    Fabric is one of the most common materials in our everyday lives, and accurately simulating the appearance of cloth is a critical problem in graphics, design, and virtual prototyping. But modeling and rendering fabric is very challenging because fabrics have a very complex structure, and this structure plays an important role in their visual appearance—cloth is made of fibers that are twisted into yarns which are woven into patterns. Light interacting with this complex structure produce the characteristic visual appearance that humans recognize as silk, cotton, or wool. In this paper we present an end-to-end pipeline to model and render fabrics: we introduce a novel modality to create volume models of fabric at micron resolution using CT technology coupled with photographs; a new technique to synthesize models of user-specified designs from such CT scans; and finally, an efficient algorithm to render these complex volumetric models for practical applications. This pipeline produces the most realistic images of virtual cloth to date, and opens the way to bridging the gap between real and virtual fabric appearance.

  8. Movies of cellular and sub-cellular motion by digital holographic microscopy

    PubMed Central

    Mann, Christopher J; Yu, Lingfeng; Kim, Myung K

    2006-01-01

    Background Many biological specimens, such as living cells and their intracellular components, often exhibit very little amplitude contrast, making it difficult for conventional bright field microscopes to distinguish them from their surroundings. To overcome this problem phase contrast techniques such as Zernike, Normarsky and dark-field microscopies have been developed to improve specimen visibility without chemically or physically altering them by the process of staining. These techniques have proven to be invaluable tools for studying living cells and furthering scientific understanding of fundamental cellular processes such as mitosis. However a drawback of these techniques is that direct quantitative phase imaging is not possible. Quantitative phase imaging is important because it enables determination of either the refractive index or optical thickness variations from the measured optical path length with sub-wavelength accuracy. Digital holography is an emergent phase contrast technique that offers an excellent approach in obtaining both qualitative and quantitative phase information from the hologram. A CCD camera is used to record a hologram onto a computer and numerical methods are subsequently applied to reconstruct the hologram to enable direct access to both phase and amplitude information. Another attractive feature of digital holography is the ability to focus on multiple focal planes from a single hologram, emulating the focusing control of a conventional microscope. Methods A modified Mach-Zender off-axis setup in transmission is used to record and reconstruct a number of holographic amplitude and phase images of cellular and sub-cellular features. Results Both cellular and sub-cellular features are imaged with sub-micron, diffraction-limited resolution. Movies of holographic amplitude and phase images of living microbes and cells are created from a series of holograms and reconstructed with numerically adjustable focus, so that the moving object

  9. A coarse-grained model for the simulations of biomolecular interactions in cellular environments

    SciTech Connect

    Xie, Zhong-Ru; Chen, Jiawen; Wu, Yinghao

    2014-02-07

    The interactions of bio-molecules constitute the key steps of cellular functions. However, in vivo binding properties differ significantly from their in vitro measurements due to the heterogeneity of cellular environments. Here we introduce a coarse-grained model based on rigid-body representation to study how factors such as cellular crowding and membrane confinement affect molecular binding. The macroscopic parameters such as the equilibrium constant and the kinetic rate constant are calibrated by adjusting the microscopic coefficients used in the numerical simulations. By changing these model parameters that are experimentally approachable, we are able to study the kinetic and thermodynamic properties of molecular binding, as well as the effects caused by specific cellular environments. We investigate the volumetric effects of crowded intracellular space on bio-molecular diffusion and diffusion-limited reactions. Furthermore, the binding constants of membrane proteins are currently difficult to measure. We provide quantitative estimations about how the binding of membrane proteins deviates from soluble proteins under different degrees of membrane confinements. The simulation results provide biological insights to the functions of membrane receptors on cell surfaces. Overall, our studies establish a connection between the details of molecular interactions and the heterogeneity of cellular environments.

  10. Continuum representations of cellular solids

    SciTech Connect

    Neilsen, M.K.

    1993-09-01

    Cellular materials consist of interconnected struts or plates which form cells. The struts or plates are constructed from a variety of metals, polymers, ceramics and wood products. Cellular materials are often used in impact limiters for shipping containers to protect the contents from accidental impact events. These materials exhibit a variety of complex behavior when subjected to crushing loads. This research focuses on the development of continuum representations of cellular solids that can be used in the finite element analysis of shipping container accidents. A significant portion of this work is the development of a new methodology to relate localized deformations to appropriate constitutive descriptions. This methodology provides the insight needed to select constitutive descriptions for cellular solids that capture the localized deformations that are observed experimentally. Constitutive relations are developed for two different cellular materials, aluminum honeycomb and polyurethane foam. These constitutive relations are based on plasticity and continuum damage theories. Plasticity is used to describe the permanent deformation exhibited by both aluminum honeycomb and polyurethane foam. Continuum damage is needed to capture the change in elastic parameters due to cracking of the polyurethane cell wall materials. The new constitutive description of polyurethane foam is implemented in both static and dynamic finite element codes, and analytical and numerical predictions are compared with available experimental data.

  11. The effect of volumetric (3D) tactile symbols within inclusive tactile maps.

    PubMed

    Gual, Jaume; Puyuelo, Marina; Lloveras, Joaquim

    2015-05-01

    Point, linear and areal elements, which are two-dimensional and of a graphic nature, are the morphological elements employed when designing tactile maps and symbols for visually impaired users. However, beyond the two-dimensional domain, there is a fourth group of elements - volumetric elements - which mapmakers do not take sufficiently into account when it comes to designing tactile maps and symbols. This study analyses the effect of including volumetric, or 3D, symbols within a tactile map. In order to do so, the researchers compared two tactile maps. One of them uses only two-dimensional elements and is produced using thermoforming, one of the most popular systems in this field, while the other includes volumetric symbols, thus highlighting the possibilities opened up by 3D printing, a new area of production. The results of the study show that including 3D symbols improves the efficiency and autonomous use of these products. PMID:25683526

  12. Volumetric reach comparison of possible end-effectors for the articulated transporter and manipulator system

    SciTech Connect

    Kress, R.L.; Babcock, S.M.; Hamel, W.R. ); Bills, K.C. )

    1990-01-01

    The goal of this research was to investigate the performance of the Articulated Transporter and Manipulator System (ATMS) during various tasks relative to the choice of wrist/end-effector configuration. The approach taken was to generate computer graphics-aided three-dimensional interactive application (CATIA) system-based models of four wrist/end-effector combinations and consider the volumetric reach of each of these configurations based on the capacity of the ATMS. The results indicate that a simple, lightweight end-effector provides a greater volumetric reach. The greatest variation presented herein is {approximately}40% when comparing a 7-degree-of-freedom (DOF) dexterous arm with a simple 3-DOF arm; however, the benefit of increasing volumetric reach by only 40% by using a simple arm may be outweighed by the loss of dexterity. 10 refs., 5 figs., 3 tabs.

  13. Ultrahigh volumetric capacitance and cyclic stability of fluorine and nitrogen co-doped carbon microspheres

    PubMed Central

    Zhou, Junshuang; Lian, Jie; Hou, Li; Zhang, Junchuan; Gou, Huiyang; Xia, Meirong; Zhao, Yufeng; Strobel, Timothy A.; Tao, Lu; Gao, Faming

    2015-01-01

    Highly porous nanostructures with large surface areas are typically employed for electrical double-layer capacitors to improve gravimetric energy storage capacity; however, high surface area carbon-based electrodes result in poor volumetric capacitance because of the low packing density of porous materials. Here, we demonstrate ultrahigh volumetric capacitance of 521 F cm−3 in aqueous electrolytes for non-porous carbon microsphere electrodes co-doped with fluorine and nitrogen synthesized by low-temperature solvothermal route, rivaling expensive RuO2 or MnO2 pseudo-capacitors. The new electrodes also exhibit excellent cyclic stability without capacitance loss after 10,000 cycles in both acidic and basic electrolytes at a high charge current of 5 A g−1. This work provides a new approach for designing high-performance electrodes with exceptional volumetric capacitance with high mass loadings and charge rates for long-lived electrochemical energy storage systems. PMID:26415838

  14. 47 CFR 22.972 - Interference resolution procedures.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 2 2014-10-01 2014-10-01 false Interference resolution procedures. 22.972 Section 22.972 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES PUBLIC MOBILE SERVICES Cellular Radiotelephone Service § 22.972 Interference resolution procedures. (a) Initial notification. (1)...

  15. 47 CFR 22.972 - Interference resolution procedures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Interference resolution procedures. 22.972 Section 22.972 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES PUBLIC MOBILE SERVICES Cellular Radiotelephone Service § 22.972 Interference resolution procedures. (a) Initial notification. (1)...

  16. Effect of elevation resolution on evapotranspiration simulations using MODFLOW.

    PubMed

    Kambhammettu, B V N P; Schmid, Wolfgang; King, James P; Creel, Bobby J

    2012-01-01

    Surface elevations represented in MODFLOW head-dependent packages are usually derived from digital elevation models (DEMs) that are available at much high resolution. Conventional grid refinement techniques to simulate the model at DEM resolution increases computational time, input file size, and in many cases are not feasible for regional applications. This research aims at utilizing the increasingly available high resolution DEMs for effective simulation of evapotranspiration (ET) in MODFLOW as an alternative to grid refinement techniques. The source code of the evapotranspiration package is modified by considering for a fixed MODFLOW grid resolution and for different DEM resolutions, the effect of variability in elevation data on ET estimates. Piezometric head at each DEM cell location is corrected by considering the gradient along row and column directions. Applicability of the research is tested for the lower Rio Grande (LRG) Basin in southern New Mexico. The DEM at 10 m resolution is aggregated to resampled DEM grid resolutions which are integer multiples of MODFLOW grid resolution. Cumulative outflows and ET rates are compared at different coarse resolution grids. Results of the analysis conclude that variability in depth-to-groundwater within the MODFLOW cell is a major contributing parameter to ET outflows in shallow groundwater regions. DEM aggregation methods for the LRG Basin have resulted in decreased volumetric outflow due to the formation of a smoothing error, which lowered the position of water table to a level below the extinction depth. PMID:21916891

  17. Ion beam analysis based on cellular nonlinear networks

    NASA Astrophysics Data System (ADS)

    Senger, V.; Tetzlaff, R.; Reichau, H.; Ratzinger, U.

    2011-07-01

    The development of a non- destructive measurement method for ion beam parameters has been treated in various projects. Although results are promising, the high complexity of beam dynamics has made it impossible to implement a real time process control up to now. In this paper we will propose analysing methods based on the dynamics of Cellular Nonlinear Networks (CNN) that can be implemented on pixel parallel CNN based architectures and yield satisfying results even at low resolutions.

  18. Measurement of in vivo cerebral volumetric strain induced by the Valsalva maneuver.

    PubMed

    Mousavi, Seyed Reza; Fehlner, Andreas; Streitberger, Kaspar-Josche; Braun, Jürgen; Samani, Abbas; Sack, Ingolf

    2014-05-01

    Compressibility of biological tissues such as brain parenchyma is related to its poroelastic nature characterized by the geometry and pressure of vasculature and interconnected fluid-filled spaces. Thus, cerebral volumetric strain may be sensitive to intracranial pressure which can be altered under physiological conditions. So far volumetric strain has attained little attention in studies of the mechanical behavior of the brain. This paper reports a study of measuring the in vivo cerebral volumetric strain induced by the Valsalva maneuver (VM) where forced expiration against a closed glottis leads to a transient increase in the intracranial pressure. For this purpose we applied three-dimensional magnetic resonance imaging equipped with a patient-controlled acquisition system to five healthy volunteers. With each volunteer, three experiments were performed: one with VM and two in resting state. i.e. normal ventilation, which were conducted before and after VM. The VM data were registered to reference data by morphology based non-rigid deformation, yielding 3D maps of total displacements and volumetric strain. On average, VM induced volumetric strain correlated to whole-brain dilatation of -3.14±0.87% and -2.80±0.71% compared to the reference states before and after VM, respectively. These values were well reproduced by repetitive experiments during the same scan as well as by repeated measurements in one volunteer on different days. Combined with literature data of intracranial pressure changes, our volumetric strain values can be used to elucidate the static compression modulus of the in vivo human brain. These results add knowledge to the understanding of the brain׳s biomechanical properties under physiological conditions. PMID:24656483

  19. Nanoscale distribution of mitochondrial import receptor Tom20 is adjusted to cellular conditions and exhibits an inner-cellular gradient.

    PubMed

    Wurm, Christian A; Neumann, Daniel; Lauterbach, Marcel A; Harke, Benjamin; Egner, Alexander; Hell, Stefan W; Jakobs, Stefan

    2011-08-16

    The translocase of the mitochondrial outer membrane (TOM) complex is the main import pore for nuclear-encoded proteins into mitochondria, yet little is known about its spatial distribution within the outer membrane. Super-resolution stimulated emission depletion microscopy was used to determine quantitatively the nanoscale distribution of Tom20, a subunit of the TOM complex, in more than 1,000 cells. We demonstrate that Tom20 is located in clusters whose nanoscale distribution is finely adjusted to the cellular growth conditions as well as to the specific position of a cell within a microcolony. The density of the clusters correlates to the mitochondrial membrane potential. The distributions of clusters of Tom20 and of Tom22 follow an inner-cellular gradient from the perinuclear to the peripheral mitochondria. We conclude that the nanoscale distribution of the TOM complex is finely adjusted to the cellular conditions, resulting in distribution gradients both within single cells and between adjacent cells. PMID:21799113

  20. Aging, Cellular Senescence, and Cancer

    PubMed Central

    Campisi, Judith

    2014-01-01

    For most species, aging promotes a host of degenerative pathologies that are characterized by debilitating losses of tissue or cellular function. However, especially among vertebrates, aging also promotes hyperplastic pathologies, the most deadly of which is cancer. In contrast to the loss of function that characterizes degenerating cells and tissues, malignant (cancerous) cells must acquire new (albeit aberrant) functions that allow them to develop into a lethal tumor. This review discusses the idea that, despite seemingly opposite characteristics, the degenerative and hyperplastic pathologies of aging are at least partly linked by a common biological phenomenon: a cellular stress response known as cellular senescence. The senescence response is widely recognized as a potent tumor suppressive mechanism. However, recent evidence strengthens the idea that it also drives both degenerative and hyper-plastic pathologies, most likely by promoting chronic inflammation. Thus, the senescence response may be the result of antagonistically pleiotropic gene action. PMID:23140366

  1. Aging, cellular senescence, and cancer.

    PubMed

    Campisi, Judith

    2013-01-01

    For most species, aging promotes a host of degenerative pathologies that are characterized by debilitating losses of tissue or cellular function. However, especially among vertebrates, aging also promotes hyperplastic pathologies, the most deadly of which is cancer. In contrast to the loss of function that characterizes degenerating cells and tissues, malignant (cancerous) cells must acquire new (albeit aberrant) functions that allow them to develop into a lethal tumor. This review discusses the idea that, despite seemingly opposite characteristics, the degenerative and hyperplastic pathologies of aging are at least partly linked by a common biological phenomenon: a cellular stress response known as cellular senescence. The senescence response is widely recognized as a potent tumor suppressive mechanism. However, recent evidence strengthens the idea that it also drives both degenerative and hyperplastic pathologies, most likely by promoting chronic inflammation. Thus, the senescence response may be the result of antagonistically pleiotropic gene action. PMID:23140366

  2. Fracture mechanics of cellular glass

    NASA Technical Reports Server (NTRS)

    Zwissler, J. G.; Adams, M. A.

    1981-01-01

    The fracture mechanics of cellular glasses (for the structural substrate of mirrored glass for solr concentrator reflecting panels) are discussed. Commercial and developmental cellular glasses were tested and analyzed using standard testing techniques and models developed from linear fracture mechanics. Two models describing the fracture behavior of these materials were developed. Slow crack growth behavior in cellular glass was found to be more complex than that encountered in dense glasses or ceramics. The crack velocity was found to be strongly dependent upon water vapor transport to the tip of the moving crack. The existence of a static fatigue limit was not conclusively established, however, it is speculated that slow crack growth behavior in Region 1 may be slower, by orders of magnitude, than that found in dense glasses.

  3. Cellular-based preemption system

    NASA Technical Reports Server (NTRS)

    Bachelder, Aaron D. (Inventor)

    2011-01-01

    A cellular-based preemption system that uses existing cellular infrastructure to transmit preemption related data to allow safe passage of emergency vehicles through one or more intersections. A cellular unit in an emergency vehicle is used to generate position reports that are transmitted to the one or more intersections during an emergency response. Based on this position data, the one or more intersections calculate an estimated time of arrival (ETA) of the emergency vehicle, and transmit preemption commands to traffic signals at the intersections based on the calculated ETA. Additional techniques may be used for refining the position reports, ETA calculations, and the like. Such techniques include, without limitation, statistical preemption, map-matching, dead-reckoning, augmented navigation, and/or preemption optimization techniques, all of which are described in further detail in the above-referenced patent applications.

  4. Rapid Volumetric MRI Using Parallel Imaging With Order-of-Magnitude Accelerations and a 32-Element RF Coil Array: Feasibility and Implications1

    PubMed Central

    Sodickson, Daniel K.; Hardy, Christopher J.; Zhu, Yudong; Giaquinto, Randy O.; Gross, Patrick; Kenwood, Gontran; Niendorf, Thoralf; Lejay, Hubert; McKenzie, Charles A.; Ohliger, Michael A.; Grant, Aaron K.; Rofsky, Neil M.

    2007-01-01

    Rationale and Objectives Many clinical applications of Magnetic Resonance Imaging are constrained by basic limits on imaging speed. Parallel MRI relaxes these limits by using the sensitivity patterns of arrays of radiofrequency receiver coils to encode spatial information in a manner complementary to traditional encoding with magnetic field gradients. Until now, parallel MRI has been used to achieve modest improvements in imaging speed; order-of-magnitude improvements have been elusive given fundamental losses in signal-to-noise ratio. The goal of this work was to demonstrate that, with appropriate hardware and careful SNR management, rapid volumetric imaging at high accelerations is in fact feasible. Materials and Methods Contrast-enhanced MRI with an axial 3D spoiled gradient echo imaging sequence was performed in healthy adult subjects using a 32-element RF coil array and a prototype 32-channel MR imaging system. Large imaging volumes were prescribed, in place of traditional limited slabs targeted only to suspect regions. Results As much as 16-fold net accelerations of imaging were achieved repeatably using this approach. The use of large 3D volumes allowed comprehensive anatomical coverage at clinically useful spatial and/or temporal resolution. The need for careful, time-consuming, and subject-specific scan prescription was also eliminated. Conclusion The highly parallel imaging approach presented here allows previously inaccessible volumetric coverage for time-sensitive MRI examinations such as contrast-enhanced MRA, and simultaneously provides a substantially simplified imaging paradigm. The resulting capability for rapid volumetric imaging promises to combine the strengths of MRI with some of the advantages of alternative imaging modalities such as multidetector CT. PMID:15866137

  5. Compressed porous graphene particles for use as supercapacitor electrodes with excellent volumetric performance.

    PubMed

    Li, Huan; Tao, Ying; Zheng, Xiaoyu; Li, Zhengjie; Liu, Donghai; Xu, Zhao; Luo, Chong; Luo, Jiayan; Kang, Feiyu; Yang, Quan-Hong

    2015-11-28

    This work presents a new class of porous graphene particles with a three-dimensional microscale network and an ultrahigh specific surface area (2590 m(2) g(-1)), which is obtained by the KOH activation of a compact graphene hydrogel. As supercapacitor electrodes, such porous graphene particles show high compressibility and little capacitance loss when subjected to a compressive force up to 40 MPa, yielding an excellent volumetric performance with an ionic liquid electrolyte. Such carbon materials show great promise for applications needing high volumetric energy. PMID:26508470

  6. A Discretized Method for Deriving Vortex Impulse from Volumetric Datasets

    NASA Astrophysics Data System (ADS)

    Buckman, Noam; Mendelson, Leah; Techet, Alexandra

    2015-11-01

    Many biological and mechanical systems transfer momentum through a fluid by creating vortical structures. To study this mechanism, we derive a method for extracting impulse and its time derivative from flow fields observed in experiments and simulations. We begin by discretizing a thin-cored vortex filament, and extend the model to account for finite vortex core thickness and asymmetric distributions of vorticity. By solely using velocity fields to extract vortex cores and calculate circulation, this method is applicable to 3D PIV datasets, even with low spatial resolution flow fields and measurement noise. To assess the performance of this analysis method, we simulate vortex rings and arbitrary vortex structures using OpenFOAM computational fluid dynamics software and analyze the wake momentum using this model in order to validate this method. We further examine a piston-vortex experiment, using 3D synthetic particle image velocimetry (SAPIV) to capture velocity fields. Strengths, limitations, and improvements to the framework are discussed.

  7. Synthetic biology in cellular immunotherapy

    PubMed Central

    Chakravarti, Deboki; Wong, Wilson W.

    2015-01-01

    The adoptive transfer of genetically engineered T cells with cancer-targeting receptors has shown tremendous promise for eradicating tumors in clinical trials. This form of cellular immunotherapy presents a unique opportunity to incorporate advanced systems and synthetic biology approaches to create cancer therapeutics with novel functions. Here, we first review the development of synthetic receptors, switches, and circuits to control the location, duration, and strength of T cell activity against tumors. In addition, we discuss the cellular engineering and genome editing of host cells (or the chassis) to improve the efficacy of cell-based cancer therapeutics, and to reduce the time and cost of manufacturing. PMID:26088008

  8. Global properties of cellular automata

    SciTech Connect

    Jen, E.

    1986-04-01

    Cellular automata are discrete mathematical systems that generate diverse, often complicated, behavior using simple deterministic rules. Analysis of the local structure of these rules makes possible a description of the global properties of the associated automata. A class of cellular automata that generate infinitely many aperoidic temporal sequences is defined,a s is the set of rules for which inverses exist. Necessary and sufficient conditions are derived characterizing the classes of ''nearest-neighbor'' rules for which arbitrary finite initial conditions (i) evolve to a homogeneous state; (ii) generate at least one constant temporal sequence.

  9. Cellular automaton for chimera states

    NASA Astrophysics Data System (ADS)

    García-Morales, Vladimir

    2016-04-01

    A minimalistic model for chimera states is presented. The model is a cellular automaton (CA) which depends on only one adjustable parameter, the range of the nonlocal coupling, and is built from elementary cellular automata and the majority (voting) rule. This suggests the universality of chimera-like behavior from a new point of view: Already simple CA rules based on the majority rule exhibit this behavior. After a short transient, we find chimera states for arbitrary initial conditions, the system spontaneously splitting into stable domains separated by static boundaries, some synchronously oscillating and the others incoherent. When the coupling range is local, nontrivial coherent structures with different periodicities are formed.

  10. Adaptive stochastic cellular automata: Applications

    NASA Astrophysics Data System (ADS)

    Qian, S.; Lee, Y. C.; Jones, R. D.; Barnes, C. W.; Flake, G. W.; O'Rourke, M. K.; Lee, K.; Chen, H. H.; Sun, G. Z.; Zhang, Y. Q.; Chen, D.; Giles, C. L.

    1990-09-01

    The stochastic learning cellular automata model has been applied to the problem of controlling unstable systems. Two example unstable systems studied are controlled by an adaptive stochastic cellular automata algorithm with an adaptive critic. The reinforcement learning algorithm and the architecture of the stochastic CA controller are presented. Learning to balance a single pole is discussed in detail. Balancing an inverted double pendulum highlights the power of the stochastic CA approach. The stochastic CA model is compared to conventional adaptive control and artificial neural network approaches.

  11. Cellular senescence in aging primates.

    PubMed

    Herbig, Utz; Ferreira, Mark; Condel, Laura; Carey, Dee; Sedivy, John M

    2006-03-01

    The aging of organisms is characterized by a gradual functional decline of all organ systems. Mammalian somatic cells in culture display a limited proliferative life span, at the end of which they undergo an irreversible cell cycle arrest known as replicative senescence. Whether cellular senescence contributes to organismal aging has been controversial. We investigated telomere dysfunction, a recently discovered biomarker of cellular senescence, and found that the number of senescent fibroblasts increases exponentially in the skin of aging baboons, reaching >15% of all cells in very old individuals. In addition, the same cells contain activated ataxia-telangiectasia mutated kinase and heterochromatinized nuclei, confirming their senescent status. PMID:16456035

  12. Cellular basis of Alzheimer's disease.

    PubMed

    Bali, Jitin; Halima, Saoussen Ben; Felmy, Boas; Goodger, Zoe; Zurbriggen, Sebastian; Rajendran, Lawrence

    2010-12-01

    Alzheimer's disease (AD) is the most common form of neurodegenerative disease. A characteristic feature of the disease is the presence of amyloid-β (Aβ) which either in its soluble oligomeric form or in the plaque-associated form is causally linked to neurodegeneration. Aβ peptide is liberated from the membrane-spanning -amyloid precursor protein by sequential proteolytic processing employing β- and γ-secretases. All these proteins involved in the production of Aβ peptide are membrane associated and hence, membrane trafficking and cellular compartmentalization play important roles. In this review, we summarize the key cellular events that lead to the progression of AD. PMID:21369424

  13. Effects of atmospheric stability on the evolution of wind turbine wakes: Volumetric LiDAR scans

    NASA Astrophysics Data System (ADS)

    Valerio Iungo, Giacomo; Porté-Agel, Fernando

    2014-05-01

    Aerodynamic optimization of wind farm layout is a fundamental task to reduce wake effects on downstream wind turbines, thus to maximize wind power harvesting. However, downstream evolution and recovery of wind turbine wakes are strongly affected by the characteristics of the incoming atmospheric boundary layer (ABL) flow, like the vertical profiles of the mean wind velocity and the turbulence intensity, which are in turn affected by the ABL stability regime. Therefore, the characterization of the variability of wind turbine wakes under different ABL stability regimes becomes fundamental to better predict wind power harvesting and improve wind farm efficiency. To this aim, wind velocity measurements of the wake produced by a 2 MW Enercon E-70 wind turbine were performed with three scanning Doppler wind Light Detection and Ranging (LiDAR) instruments. One LiDAR was typically devoted to the characterization of the incoming wind, in particular wind velocity, shear and turbulence intensity at the height of the rotor disc. The other two LiDARs performed scans in order to characterize the wake velocity field produced by the tested wind turbine. The main challenge in performing field measurements of wind turbine wakes is represented by the varying wind conditions, and by the consequent adjustments of the turbine yaw angle needed to maximize power production. Consequently, taking into account possible variations of the relative position between LiDAR measurement volume and wake location, different LiDAR measurement procedures were carried out in order to perform 2-D and 3-D characterizations of the mean wake velocity field. However, larger measurement volumes and higher spatial resolution require longer sampling periods; thus, to investigate wake turbulence tests were also performed by staring the LiDAR laser beam over fixed directions and with the maximum sampling frequency. Furthermore, volumetric scans of the wind turbine wake were performed under different wind

  14. A high-efficiency cellular extraction system for biological proteomics

    PubMed Central

    Dhabaria, Avantika; Cifani, Paolo; Reed, Casie; Steen, Hanno; Kentsis, Alex

    2015-01-01

    Recent developments in quantitative high-resolution mass spectrometry have led to significant improvements in the sensitivity and specificity of biochemical analyses of cellular reactions, protein-protein interactions, and small molecule drug discovery. These approaches depend on cellular proteome extraction that preserves native protein activities. Here, we systematically analyzed mechanical methods of cell lysis and physical protein extraction to identify those that maximize the extraction of cellular proteins while minimizing their denaturation. Cells were mechanically disrupted using Potter-Elvehjem homogenization, probe or adaptive focused acoustic sonication, and in the presence of various detergents, including polyoxyethylene ethers and esters, glycosides, and zwitterions. Using fluorescence spectroscopy, biochemical assays, and mass spectrometry proteomics, we identified the combination of adaptive focused acoustic (AFA) sonication in the presence of binary poloxamer-based mixture of octyl-β-glucoside and Pluronic F-127 to maximize the depth and yield of proteome extraction while maintaining native protein activity. This binary poloxamer extraction system allowed native proteome extraction, comparable in coverage to proteomes extracted using denaturing SDS or guanidine containing buffers, including efficient extraction of all major cellular organelles. This high-efficiency cellular extraction system should prove useful for a variety of cell biochemical studies, including structural and functional proteomics. PMID:26153614

  15. A nanotube based electron microbeam cellular irradiator for radiobiology research

    SciTech Connect

    Bordelon, David E.; Zhang Jian; Graboski, Sarah; Cox, Adrienne; Schreiber, Eric; Chang, Sha; Zhou, Otto Z.

    2008-12-15

    A prototype cellular irradiator utilizing a carbon nanotube (CNT) based field emission electron source has been developed for microscopic image-guided cellular region irradiation. The CNT cellular irradiation system has shown great potential to be a high temporal and spatial resolution research tool to enable researchers to gain a better understanding of the intricate cellular and intercellular microprocesses occurring following radiation deposition, which is essential to improving radiotherapy cancer treatment outcomes. In this paper, initial results of the system development are reported. The relationship between field emission current, the dose rate, and the dose distribution has been investigated. A beam size of 23 {mu}m has been achieved with variable dose rates of 1-100 Gy/s, and the system dosimetry has been measured using a radiochromic film. Cell irradiation has been demonstrated by the visualization of H2AX phosphorylation at DNA double-strand break sites following irradiation in a rat fibroblast cell monolayer. The prototype single beam cellular irradiator is a preliminary step to a multipixel cell irradiator that is under development.

  16. A nanotube based electron microbeam cellular irradiator for radiobiology research

    NASA Astrophysics Data System (ADS)

    Bordelon, David E.; Zhang, Jian; Graboski, Sarah; Cox, Adrienne; Schreiber, Eric; Zhou, Otto Z.; Chang, Sha

    2008-12-01

    A prototype cellular irradiator utilizing a carbon nanotube (CNT) based field emission electron source has been developed for microscopic image-guided cellular region irradiation. The CNT cellular irradiation system has shown great potential to be a high temporal and spatial resolution research tool to enable researchers to gain a better understanding of the intricate cellular and intercellular microprocesses occurring following radiation deposition, which is essential to improving radiotherapy cancer treatment outcomes. In this paper, initial results of the system development are reported. The relationship between field emission current, the dose rate, and the dose distribution has been investigated. A beam size of 23 μm has been achieved with variable dose rates of 1-100 Gy/s, and the system dosimetry has been measured using a radiochromic film. Cell irradiation has been demonstrated by the visualization of H2AX phosphorylation at DNA double-strand break sites following irradiation in a rat fibroblast cell monolayer. The prototype single beam cellular irradiator is a preliminary step to a multipixel cell irradiator that is under development.

  17. A nanotube based electron microbeam cellular irradiator for radiobiology research.

    PubMed

    Bordelon, David E; Zhang, Jian; Graboski, Sarah; Cox, Adrienne; Schreiber, Eric; Zhou, Otto Z; Chang, Sha

    2008-12-01

    A prototype cellular irradiator utilizing a carbon nanotube (CNT) based field emission electron source has been developed for microscopic image-guided cellular region irradiation. The CNT cellular irradiation system has shown great potential to be a high temporal and spatial resolution research tool to enable researchers to gain a better understanding of the intricate cellular and intercellular microprocesses occurring following radiation deposition, which is essential to improving radiotherapy cancer treatment outcomes. In this paper, initial results of the system development are reported. The relationship between field emission current, the dose rate, and the dose distribution has been investigated. A beam size of 23 mum has been achieved with variable dose rates of 1-100 Gy/s, and the system dosimetry has been measured using a radiochromic film. Cell irradiation has been demonstrated by the visualization of H2AX phosphorylation at DNA double-strand break sites following irradiation in a rat fibroblast cell monolayer. The prototype single beam cellular irradiator is a preliminary step to a multipixel cell irradiator that is under development. PMID:19123587

  18. A High-Efficiency Cellular Extraction System for Biological Proteomics.

    PubMed

    Dhabaria, Avantika; Cifani, Paolo; Reed, Casie; Steen, Hanno; Kentsis, Alex

    2015-08-01

    Recent developments in quantitative high-resolution mass spectrometry have led to significant improvements in the sensitivity and specificity of the biochemical analyses of cellular reactions, protein-protein interactions, and small-molecule-drug discovery. These approaches depend on cellular proteome extraction that preserves native protein activities. Here, we systematically analyzed mechanical methods of cell lysis and physical protein extraction to identify those that maximize the extraction of cellular proteins while minimizing their denaturation. Cells were mechanically disrupted using Potter-Elvehjem homogenization, probe- or adaptive-focused acoustic sonication, and were in the presence of various detergents, including polyoxyethylene ethers and esters, glycosides, and zwitterions. Using fluorescence spectroscopy, biochemical assays, and mass spectrometry proteomics, we identified the combination of adaptive focused acoustic (AFA) sonication in the presence of a binary poloxamer-based mixture of octyl-β-glucoside and Pluronic F-127 to maximize the depth and yield of the proteome extraction while maintaining native protein activity. This binary poloxamer extraction system allowed for native proteome extraction comparable in coverage to the proteomes extracted using denaturing SDS or guanidine-containing buffers, including the efficient extraction of all major cellular organelles. This high-efficiency cellular extraction system should prove useful for a variety of cell biochemical studies, including structural and functional proteomics. PMID:26153614

  19. Wrinkling in Cellular Structured Composites

    NASA Astrophysics Data System (ADS)

    Kaynia, Narges; Li, Yaning; Boyce, Mary C.

    2013-03-01

    Many structured composites found in nature possess undulating and wrinkled interfacial layers that regulate mechanical, chemical, acoustic, adhesive, thermal, electrical and optical functions of the material. This research focused on the formation of wrinkling patterns in cellular structured composites and the effect of the wrinkling pattern on the overall structural response. The cellular composites consisted of stiffer interfacial layers constructing a network submerged in a soft matrix. Analytical and finite element models were developed to capture various aspects of the wrinkling mechanism. The characteristics of the undulation patterns and the instability modes were investigated as functions of model geometry and material composition. Mechanical experiments were designed to further explore the modeling results. The cellular composite samples were fabricated by using different types of elastomers and by varying the geometry and the material properties. The experimental and numerical results were consistent with the analytical predictions. The results in this research improve understanding of the mechanisms governing the undulation pattern formation in cellular composites and can be used to enable on-demand tunability of different functions to provide, among others, active control of wave propagation, mechanical stiffness and deformation, and material swelling and growth.

  20. Cellular Automata and the Humanities.

    ERIC Educational Resources Information Center

    Gallo, Ernest

    1994-01-01

    The use of cellular automata to analyze several pre-Socratic hypotheses about the evolution of the physical world is discussed. These hypotheses combine characteristics of both rigorous and metaphoric language. Since the computer demands explicit instructions for each step in the evolution of the automaton, such models can reveal conceptual…

  1. Sparse-view image reconstruction in inverse-geometry CT (IGCT) for fast, low-dose, volumetric dental X-ray imaging

    NASA Astrophysics Data System (ADS)

    Hong, D. K.; Cho, H. S.; Oh, J. E.; Je, U. K.; Lee, M. S.; Kim, H. J.; Lee, S. H.; Park, Y. O.; Choi, S. I.; Koo, Y. S.; Cho, H. M.

    2012-12-01

    As a new direction for computed tomography (CT) imaging, inverse-geometry CT (IGCT) has been recently introduced and is intended to overcome limitations in conventional cone-beam CT (CBCT) such as the cone-beam artifacts, imaging dose, temporal resolution, scatter, cost, and so on. While the CBCT geometry consists of X-rays emanating from a small focal spot and collimated toward a larger detector, the IGCT geometry employs a large-area scanned source array with the Xray beams collimated toward a smaller-area detector. In this research, we explored an effective IGCT reconstruction algorithm based on the total-variation (TV) minimization method and studied the feasibility of the IGCT geometry for potential applications to fast, low-dose volumetric dental X-ray imaging. We implemented the algorithm, performed systematic simulation works, and evaluated the imaging characteristics quantitatively. Although much engineering and validation works are required to achieve clinical implementation, our preliminary results have demonstrated a potential for improved volumetric imaging with reduced dose.

  2. Volumetric restrictions in single particle 3DEM reconstruction

    PubMed Central

    Sorzano, C.O.S.; Velázquez-Muriel, J.A.; Marabini, R.; Herman, G.T.; Carazo, J.M.

    2009-01-01

    3D electron microsscopy aims at the reconstruction of density volumes corresponding to the electrostatic potential distribution of macro-molecules. There are many factors limiting the resolution achievable when this technique is applied to biological macromolecules: microscope imperfections, molecule flexibility, lack of projections from certain directions, unknown angular distribution, noise, etc. In this communication we explore the quality gain in the reconstruction by including a priori knowledge such as particle symmetry, occupied volume, known surface relief, density nonnegativity and similarity to a known volume in order to improve the quality of the reconstruction. If the reconstruction is represented as a series expansion, such constraints can be expressed by set of equations that the expansion coefficients must satisfy. In this work, these equation sets are specified and combined in a novel way with the ART + blobs reconstruction algorithm. The effect of each one on the reconstruction of a realistic phantom is explored. Finally, the application of these restrictions to 3D reconstructions from experimental data are studied. PMID:20119498

  3. Physiological Noise Reduction Using Volumetric Functional Magnetic Resonance Inverse Imaging

    PubMed Central

    Lin, Fa-Hsuan; Nummenmaa, Aapo; Witzel, Thomas; Polimeni, Jonathan R.; Zeffiro, Thomas A.; Wang, Fu-Nien; Belliveau, John W.

    2013-01-01

    Physiological noise arising from a variety of sources can significantly degrade the detection of task-related activity in BOLD-contrast fMRI experiments. If whole head spatial coverage is desired, effective suppression of oscillatory physiological noise from cardiac and respiratory fluctuations is quite difficult without external monitoring, since traditional EPI acquisition methods cannot sample the signal rapidly enough to satisfy the Nyquist sampling theorem, leading to temporal aliasing of noise. Using a combination of high speed magnetic resonance inverse imaging (InI) and digital filtering, we demonstrate that it is possible to suppress cardiac and respiratory noise without auxiliary monitoring, while achieving whole head spatial coverage and reasonable spatial resolution. Our systematic study of the effects of different moving average (MA) digital filters demonstrates that a MA filter with a 2 s window can effectively reduce the variance in the hemodynamic baseline signal, thereby achieving 57-58% improvements in peak z-statistic values compared to unfiltered InI or spatially smoothed EPI data (FWHM =8.6 mm). In conclusion, the high temporal sampling rates achievable with InI permit significant reductions in physiological noise using standard temporal filtering techniques that result in significant improvements in hemodynamic response estimation. PMID:21954026

  4. Structural and Functional Analysis of Intact Hair Follicles and Pilosebaceous Units by Volumetric Multispectral Optoacoustic Tomography.

    PubMed

    Ford, Steven J; Bigliardi, Paul L; Sardella, Thomas C P; Urich, Alexander; Burton, Neal C; Kacprowicz, Marcin; Bigliardi, Mei; Olivo, Malini; Razansky, Daniel

    2016-04-01

    Visualizing anatomical and functional features of hair follicle development in their unperturbed environment is key in understanding complex mechanisms of hair pathophysiology and in discovery of novel therapies. Of particular interest is in vivo visualization of the intact pilosebaceous unit, vascularization of the hair bulb, and evaluation of the hair cycle, particularly in humans. Furthermore, noninvasive visualization of the sebaceous glands could offer crucial insight into the pathophysiology of follicle-related diseases and dry or seborrheic skin, in particular by combining in vivo imaging with other phenotyping, genotyping, and microbial analyses. The available imaging techniques are limited in their ability for deep tissue in vivo imaging of hair follicles and lipid-rich sebaceous glands in their entirety without biopsy. We developed a noninvasive, painless, and risk-free volumetric multispectral optoacoustic tomography method for deep tissue three-dimensional visualization of whole hair follicles and surrounding structures with high spatial resolution below 80 μm. Herein we demonstrate on-the-fly assessment of key morphometric parameters of follicles and lipid content as well as functional oxygenation parameters of the associated capillary bed. The ease of handheld operation and versatility of the newly developed approach poise it as an indispensable tool for early diagnosis of disorders of the pilosebaceous unit and surrounding structures, and for monitoring the efficacy of cosmetic and therapeutic interventions. PMID:26743603

  5. Developing a Near-Continuous Estimation of Volumetric Fluctuations in Tropical Lakes and Reservoirs Using Satellite Remote Sensing

    NASA Astrophysics Data System (ADS)

    Keys, T.; Scott, D.

    2015-12-01

    Lakes and reservoirs play an integral role in water resources management by storing large quantities of water commonly used for irrigation, hydroelectric power, water supply, and flood mitigation. Knowing the exact quantity of stored water and necessary water for each of these usages is a critical component of sustainable water resources management. However, limited amounts of hydrologic data in developing nations, most of which are located in the tropics, hinders the accurate monitoring of water storage and allocation. Recent improvements in remote sensing have greatly enhanced the ability to calculate volumetric fluctuations of lakes and reservoirs at given points through time but are limited by temporal resolution as well as the computational time required for image processing. This study utilizes the newly developed MODISTools package for the programming language R in conjunction with satellite altimetry from three different altimetry databases to estimate lake and reservoir volumes at eight day intervals over a 15 year period. The study specifically examines three large lakes and reservoirs: Balbina Reservoir in the Amazon River Basin, Lake Tana in the Nile River Basin, and Tonle Sap Lake in the Mekong River Basin. Altimetry-based water level estimations are validated by in situ water level data from monitoring stations while surface area estimations are validated by Sound Navigation and Ranging (SONAR) generated bathymetric maps with corresponding stage-area relationships. Preliminary results indicate that both remotely sensed water levels and surface areas agree well with in situ measurements, supporting the appropriateness of this methodology.

  6. High resolution pipette

    DOEpatents

    Beroz, Justin Douglas; Hart, Anastasios John

    2016-06-07

    A pipette includes a movable piston and a diaphragm that at least partly defines a fluid chamber enclosing a volume of working fluid. The piston displaces a volumetric amount of the working fluid in the chamber when moved. In response, the diaphragm displaces a smaller volumetric amount of fluid outside the chamber. A deamplification ratio is defined by the ratio of the volume displaced by the diaphragm to the volume displaced by the piston. The deamplification ratio is adjustable by adjusting or changing the diaphragm and/or by adjusting the size of the fluid chamber. The deamplifying pipette enables measuring and dispensing of very small volumes of liquid and is easily adapted to commercially available pipette components. Pipette components such as a pipette tip or adaptor may include a diaphragm to enable deamplification of the nominal volume capacity of a given pipette device.

  7. EVALUATION OF VOLUMETRIC LEAK DETECTION METHODS USED IN UNDERGROUND STORAGE TANKS

    EPA Science Inventory

    This reports documents a research program which evaluated the performance of 25 commercially available volumetric test methods for the detection of small leaks in underground gasoline storage tanks. he evaluations were performed at the U.S. EPA Risk Reduction Engineering Laborato...

  8. Optical Addressing of Multi-Colour Photochromic Material Mixture for Volumetric Display

    PubMed Central

    Hirayama, Ryuji; Shiraki, Atsushi; Naruse, Makoto; Nakamura, Shinichiro; Nakayama, Hirotaka; Kakue, Takashi; Shimobaba, Tomoyoshi; Ito, Tomoyoshi

    2016-01-01

    This is the first study to demonstrate that colour transformations in the volume of a photochromic material (PM) are induced at the intersections of two control light channels, one controlling PM colouration and the other controlling decolouration. Thus, PM colouration is induced by position selectivity, and therefore, a dynamic volumetric display may be realised using these two control lights. Moreover, a mixture of multiple PM types with different absorption properties exhibits different colours depending on the control light spectrum. Particularly, the spectrum management of the control light allows colour-selective colouration besides position selectivity. Therefore, a PM-based, full-colour volumetric display is realised. We experimentally construct a mixture of two PM types and validate the operating principles of such a volumetric display system. Our system is constructed simply by mixing multiple PM types; therefore, the display hardware structure is extremely simple, and the minimum size of a volume element can be as small as the size of a molecule. Volumetric displays can provide natural three-dimensional (3D) perception; therefore, the potential uses of our system include high-definition 3D visualisation for medical applications, architectural design, human–computer interactions, advertising, and entertainment. PMID:27526780

  9. Power Outputs and Volumetric Eruption Rates for Ionian Volcanoes from Galileo-NIMS Data

    NASA Technical Reports Server (NTRS)

    Davies, A. G.

    2001-01-01

    Volumetric eruption rates for a number of Io volcanoes are calculated as a function of volcanic thermal output. Thermal output is determined using 2-temperature fits to NIMS data. Typical eruption rates are larger than terrestrial eruptions of similar style. Additional information is contained in the original extended abstract.

  10. 40 CFR 80.170 - Volumetric additive reconciliation (VAR), equipment calibration, and recordkeeping requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ADDITIVES Detergent Gasoline § 80.170 Volumetric additive reconciliation (VAR), equipment calibration, and recordkeeping requirements. This section contains requirements for automated detergent blending facilities and hand-blending detergent facilities. All gasoline and all PRC intended for use in gasoline must...

  11. 40 CFR 80.157 - Volumetric additive reconciliation (“VAR”), equipment calibration, and recordkeeping requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ADDITIVES Detergent Gasoline § 80.157 Volumetric additive reconciliation (“VAR”), equipment calibration, and recordkeeping requirements. This section contains requirements for automated detergent blending facilities and hand-blending detergent facilities. All gasolines and all PRC intended for use in gasoline must...

  12. Numerical evaluation of volumetric weighted mean transmissivity estimates in laterally heterogeneous aquifers

    NASA Astrophysics Data System (ADS)

    Rhode, Katherine L.; Osiensky, James L.; Miller, Stanley M.

    2007-12-01

    SummaryMost previous investigations to evaluate the "effective" or average transmissivity in heterogeneous environments have used calculations based on areas to weight the effects of each heterogeneity. Analysis of spatial volumetric variations within the cone of depression expressed at the potentiometric surface offers a more general solution to evaluate the meaning of transmissivity ( T) and storativity ( S) values derived from aquifer tests in these environments. The [Cooper Jr., H.H., Jacob, C.E. 1946. A generalized graphical method for evaluating formation constants and summarizing well-field history. Eos Trans. AGU, 27(4), 526-534] method is used to demonstrate that T variations reflected in slope changes in plots of the pumping well drawdown data correspond to changes in the volumetric weighted mean transmissivity ( VWMT) over time. Lognormal distributions of transmissivity are represented by block heterogeneities within two simulated aquifers, for both spatially random and spatially correlated data sets. By analyzing the volumetric evolution of the cone of depression observed in the potentiometric surface, the nature of T averaging within the cone of depression as a function of time is illustrated. Volumetric analysis shows that the average aquifer T varies with time as the cone of depression progressively envelops different heterogeneities. The initial trend is controlled primarily by the heterogeneities directly surrounding the pumping center. If steady-shape conditions are not achieved, late-time VWMT values do not approach an asymptotic limit.

  13. Species-specific contribution of volumetric growth and tissue convergence to posterior body elongation in vertebrates.

    PubMed

    Steventon, Ben; Duarte, Fernando; Lagadec, Ronan; Mazan, Sylvie; Nicolas, Jean-François; Hirsinger, Estelle

    2016-05-15

    Posterior body elongation is a widespread mechanism propelling the generation of the metazoan body plan. The posterior growth model predicts that a posterior growth zone generates sufficient tissue volume to elongate the posterior body. However, there are energy supply-related differences between vertebrates in the degree to which growth occurs concomitantly with embryogenesis. By applying a multi-scalar morphometric analysis in zebrafish embryos, we show that posterior body elongation is generated by an influx of cells from lateral regions, by convergence-extension of cells as they exit the tailbud, and finally by a late volumetric growth in the spinal cord and notochord. Importantly, the unsegmented region does not generate additional tissue volume. Fibroblast growth factor inhibition blocks tissue convergence rather than volumetric growth, showing that a conserved molecular mechanism can control convergent morphogenesis through different cell behaviours. Finally, via a comparative morphometric analysis in lamprey, dogfish, zebrafish and mouse, we propose that elongation via posterior volumetric growth is linked to increased energy supply and is associated with an overall increase in volumetric growth and elongation. PMID:26989170

  14. Altering the volumetric expansion ratio of a Lysholm helical screw expander

    SciTech Connect

    Dunbar, M.K.

    1984-01-01

    This is an analysis of the effects of the volumetric expansion ratio on the operation of a Lysholm helical screw expander. Extensive testing of the University of California Lysholm engine with a 5.3 volumetric expansion ratio was performed. In this experiment, the expansion ratio has been reduced from 5.3 to 4.0. Tests were performed at a variety of speeds and qualities for a 5.0 pressure ratio and at a variety of speeds and pressure ratios for 99 percent quality. It was predicted that decreasing the volumetric expansion ratio would decrease the leakage fraction and thereby increase efficiency. This occurred as predicted. Isentropic efficiency increased 20 percent for 50 percent quality steam and 16 percent for 33 percent quality steam, all for an inlet pressure of 120 psia and a speed of 9000 rpm. A maximum efficiency of 47.2 percent was reached at 33 percent quality, 9000 rpm and a pressure ratio of 5.0. It was noted that the leakage rate did not appear to be a function of expansion ratio, as had been expected. Using this fact the previous empirical models of the engine were extended to include volumetric expansion ratio as a variable parameter.

  15. Optical Addressing of Multi-Colour Photochromic Material Mixture for Volumetric Display.

    PubMed

    Hirayama, Ryuji; Shiraki, Atsushi; Naruse, Makoto; Nakamura, Shinichiro; Nakayama, Hirotaka; Kakue, Takashi; Shimobaba, Tomoyoshi; Ito, Tomoyoshi

    2016-01-01

    This is the first study to demonstrate that colour transformations in the volume of a photochromic material (PM) are induced at the intersections of two control light channels, one controlling PM colouration and the other controlling decolouration. Thus, PM colouration is induced by position selectivity, and therefore, a dynamic volumetric display may be realised using these two control lights. Moreover, a mixture of multiple PM types with different absorption properties exhibits different colours depending on the control light spectrum. Particularly, the spectrum management of the control light allows colour-selective colouration besides position selectivity. Therefore, a PM-based, full-colour volumetric display is realised. We experimentally construct a mixture of two PM types and validate the operating principles of such a volumetric display system. Our system is constructed simply by mixing multiple PM types; therefore, the display hardware structure is extremely simple, and the minimum size of a volume element can be as small as the size of a molecule. Volumetric displays can provide natural three-dimensional (3D) perception; therefore, the potential uses of our system include high-definition 3D visualisation for medical applications, architectural design, human-computer interactions, advertising, and entertainment. PMID:27526780

  16. Magnetic Resonance Imaging Volumetric Analysis of the Putamen in Children with ADHD: Combined Type versus Control

    ERIC Educational Resources Information Center

    Wellington, Tasha McMahon; Semrud-Clikeman, Margaret; Gregory, Amanda Louise; Murphy, Jennifer Mary; Lancaster, Jack Lynn

    2006-01-01

    Objective: Volumetric differences in the putamen of boys with ADHD combined subtype with psychopathic traits and controls are investigated. Method: The putamen in 24 archival magnetic resonance imaging scans of 12 boys in residential treatment with symptoms of ADHD and psychopathic traits and 12 community control boys are analyzed using Display…

  17. VASP: A Volumetric Analysis of Surface Properties Yields Insights into Protein-Ligand Binding Specificity

    PubMed Central

    Chen, Brian Y.; Honig, Barry

    2010-01-01

    Many algorithms that compare protein structures can reveal similarities that suggest related biological functions, even at great evolutionary distances. Proteins with related function often exhibit differences in binding specificity, but few algorithms identify structural variations that effect specificity. To address this problem, we describe the Volumetric Analysis of Surface Properties (VASP), a novel volumetric analysis tool for the comparison of binding sites in aligned protein structures. VASP uses solid volumes to represent protein shape and the shape of surface cavities, clefts and tunnels that are defined with other methods. Our approach, inspired by techniques from constructive solid geometry, enables the isolation of volumetrically conserved and variable regions within three dimensionally superposed volumes. We applied VASP to compute a comparative volumetric analysis of the ligand binding sites formed by members of the steroidogenic acute regulatory protein (StAR)-related lipid transfer (START) domains and the serine proteases. Within both families, VASP isolated individual amino acids that create structural differences between ligand binding cavities that are known to influence differences in binding specificity. Also, VASP isolated cavity subregions that differ between ligand binding cavities which are essential for differences in binding specificity. As such, VASP should prove a valuable tool in the study of protein-ligand binding specificity. PMID:20814581

  18. Automated volumetric grid generation for finite element modeling of human hand joints

    SciTech Connect

    Hollerbach, K.; Underhill, K.; Rainsberger, R.

    1995-02-01

    We are developing techniques for finite element analysis of human joints. These techniques need to provide high quality results rapidly in order to be useful to a physician. The research presented here increases model quality and decreases user input time by automating the volumetric mesh generation step.

  19. TECHNIQUES TO MEASURE VOLUMETRIC FLOW AND PARTICULATE CONCENTRATION IN STACKS WITH CYCLONIC FLOW

    EPA Science Inventory

    The study determined that an in-stack venturi can accurately measure volumetric flow in stacks with a severe cyclonic flow profile. The design requirements of the venturi are described in the report. The report also describes a low head loss, egg crate-shaped device that effectiv...

  20. Trapping volumetric measurement by multidetector CT in chronic obstructive pulmonary disease: Effect of CT threshold

    SciTech Connect

    Wang, Xiaohua; Yuan, Huishu; Duan, Jianghui; Du, Yipeng; Shen, Ning; He, Bei

    2013-08-15

    Purpose: The purpose of this study was to evaluate the effect of various computed tomography (CT) thresholds on trapping volumetric measurements by multidetector CT in chronic obstructive pulmonary disease (COPD).Methods: Twenty-three COPD patients were scanned with a 64-slice CT scanner in both the inspiratory and expiratory phase. CT thresholds of −950 Hu in inspiration and −950 to −890 Hu in expiration were used, after which trapping volumetric measurements were made using computer software. Trapping volume percentage (Vtrap%) under the different CT thresholds in the expiratory phase and below −950 Hu in the inspiratory phase was compared and correlated with lung function.Results: Mean Vtrap% was similar under −930 Hu in the expiratory phase and below −950 Hu in the inspiratory phase, being 13.18 ± 9.66 and 13.95 ± 6.72 (both lungs), respectively; this difference was not significant (P= 0.240). Vtrap% under −950 Hu in the inspiratory phase and below the −950 to −890 Hu threshold in the expiratory phase was moderately negatively correlated with the ratio of forced expiratory volume in one second to forced vital capacity and the measured value of forced expiratory volume in one second as a percentage of the predicted value.Conclusions: Trapping volumetric measurement with multidetector CT is a promising method for the quantification of COPD. It is important to know the effect of various CT thresholds on trapping volumetric measurements.

  1. Development, Construction, and Operation of a Multisample Volumetric Apparatus for the Study of Gas Adsorption Equilibrium

    ERIC Educational Resources Information Center

    Ribeiro, Rui P. P. L.; Silva, Ricardo J. S.; Esteves, Isabel A. A. C.; Mota, Jose´ P. B.

    2015-01-01

    The construction of a simple volumetric adsorption apparatus is highlighted. The setup is inexpensive and provides a clear demonstration of gas phase adsorption concepts. The topic is suitable for undergraduate chemistry and chemical engineering students. Moreover, this unit can also provide quantitative data that can be used by young researchers…

  2. Tunneling holes in microparticles to facilitate the transport of lithium ions for high volumetric density batteries.

    PubMed

    Zhu, Jian; Ng, K Y Simon; Deng, Da

    2015-09-14

    Microscale materials generally have a higher tap density than that of random nanoparticles. Therefore, microparticles have been attracting much attention for application as high volumetric density electrodes for lithium ion batteries. However, microparticles have much longer electrolyte diffusion and Li-ion migration length and less accessibility to the electrolyte than that of nanoparticles. Therefore, it will be interesting to tunnel-holes in the high volumetric density microparticles to facilitate the reversible storage of lithium ions. Here, tunnel-like holes were generated in microparticles to dramatically increase the accessibility of the active materials to facilitate the lithium ion transfer. A plausible formation mechanism to explain the generation of tunnel-like holes was proposed based on time-course experiments and intensive characterization. Impressively, the as-prepared microbeads with tunnels demonstrated dramatically improved performance compared to the solid microbeads without tunnels in lithium ion storage. The microparticles with tunnels could achieve comparable electrochemical performances to those nanoparticles reported in the literature, suggesting that microparticles, properly tuned, could be promising candidates as negative electrodes for lithium-ion batteries and worthy of further studies. We also directly measured the volumetric density of the microparticles. We would like to highlight that a superior volumetric capacity of 514 mA h cm(-3) has been achieved. We hope to promote more frequent use of the unit mA h cm(-3) in addition to the conventional unit mA h g(-1) in the battery community. PMID:26247159

  3. Empirical correlation of volumetric mass transfer coefficient for a rectangular internal-loop airlift bioreactor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An empirical correlation of volumetric mass transfer coefficient was developed for a pilot scale internal-loop rectangular airlift bioreactor that was designed for biotechnology. The empirical correlation combines classic turbulence theory, Kolmogorov’s isotropic turbulence theory with Higbie’s pen...

  4. High Volumetric Capacity Three-Dimensionally Sphere-Caged Secondary Battery Anodes.

    PubMed

    Liu, Jinyun; Chen, Xi; Kim, Jinwoo; Zheng, Qiye; Ning, Hailong; Sun, Pengcheng; Huang, Xingjiu; Liu, Jinhuai; Niu, Junjie; Braun, Paul V

    2016-07-13

    High volumetric energy density secondary batteries are important for many applications, which has led to considerable efforts to replace the low volumetric capacity graphite-based anode common to most Li-ion batteries with a higher energy density anode. Because most high capacity anode materials expand significantly during charging, such anodes must contain sufficient porosity in the discharged state to enable the expansion, yet not excess porosity, which lowers the overall energy density. Here, we present a high volumetric capacity anode consisting of a three-dimensional (3D) nanocomposite formed in only a few steps which includes both a 3D structured Sn scaffold and a hollow Sn sphere within each cavity where all the free Sn surfaces are coated with carbon. The anode exhibits a high volumetric capacity of ∼1700 mA h cm(-3) over 200 cycles at 0.5C, and a capacity greater than 1200 mA h cm(-3) at 10C. Importantly, the anode can even be formed into a commercially relevant ∼100 μm thick form. When assembled into a full cell the anode shows a good compatibility with a commercial LiMn2O4 cathode. In situ TEM observations confirm the electrode design accommodates the necessary volume expansion during lithiation. PMID:27322627

  5. Intervertebral disc segmentation and volumetric reconstruction from peripheral quantitative computed tomography imaging.

    PubMed

    Wong, Alexander; Mishra, Akshaya; Yates, Justin; Fieguth, Paul; Clausi, David A; Callaghan, Jack P

    2009-11-01

    An automatic system for segmenting and constructing volumetric representations of excised intervertebral discs from peripheral quantitative computed tomography (PQCT) imagery is presented. The system is designed to allow for automatic quantitative analysis of progressive herniation damage to the intervertebral discs under flexion/extension motions combined with a compressive load. Automatic segmentation and volumetric reconstruction of intervertebral disc from PQCT imagery is a very challenging problem due to factors such as streak artifacts and unclear material density separation between contrasted intervertebral disc and surrounding bone in the PQCT imagery, as well as the formation of multiple contrasted regions under axial scans. To address these factors, a novel multiscale level set approach based on the Mumford-Shah energy functional in iterative bilateral scale space is employed to segment the intervertebral disc regions from the PQCT imagery. A Delaunay triangulation is then performed based on the set of points associated with the intervertebral disc regions to construct the volumetric representation of the intervertebral disc. Experimental results show that the proposed system achieves segmentation and volumetric reconstructions of intervertebral discs with mean absolute distance error below 0.8 mm when compared to ground truth measurements. The proposed system is currently in operational use as a visualization tool for studying progressive intervertebral disc damage. PMID:19635691

  6. 40 CFR 80.157 - Volumetric additive reconciliation (“VAR”), equipment calibration, and recordkeeping requirements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... ADDITIVES Detergent Gasoline § 80.157 Volumetric additive reconciliation (“VAR”), equipment calibration, and recordkeeping requirements. This section contains requirements for automated detergent blending facilities and hand-blending detergent facilities. All gasolines and all PRC intended for use in gasoline must...

  7. 40 CFR 80.170 - Volumetric additive reconciliation (VAR), equipment calibration, and recordkeeping requirements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... ADDITIVES Detergent Gasoline § 80.170 Volumetric additive reconciliation (VAR), equipment calibration, and recordkeeping requirements. This section contains requirements for automated detergent blending facilities and hand-blending detergent facilities. All gasoline and all PRC intended for use in gasoline must...

  8. Planimetric and volumetric analysis of channel change in the post-hydraulic mining period (1906-2009) in the Central Valley, California

    NASA Astrophysics Data System (ADS)

    Ghoshal, Subhajit

    Advances in remote sensing technologies can facilitate acquisition of topographical and planimetric information in fluvial environments and can produce spatial data with high spatial and temporal resolutions. Measuring planimetric and volumetric change in fluvial sediment budgets and geomorphic change detection was used for long-term monitoring of a fluvial system. Channel and floodplain changes caused by hydraulic gold mining sediment in this system are a major example of anthropogenic impacts on a fluvial system. This study uses remote sensing change-detection techniques to examine spatial and temporal patterns of HMS redistribution at a centennial time scale, and to measure and evaluate the magnitude and processes of a major channel and floodplain metamorphosis. Five reach-scale sites along the lower Yuba River and two sites on the Feather River were chosen for detailed analysis of planimetric and volumetric changes over a period of ~100 years. Volumetric changes were measured using DEM differencing and soft-copy photogrammetry methods, and planimetric changes were recorded from rectified maps and aerial photographs. This study indicates significant changes in channel morphology and sediment storage over the last 100 years. Large deposits of historical sediment remaining in the bed, banks and terraces of the lower Yuba River were remobilized by floods. The volumetric analysis shows the results of dredging of ditches, deposition in natural levees, and net erosion of high-water channels from 1906 or 1909 to 1999. Over the last century, channels incised up to ~13 m into mining sediment deposits. Systematic uncertainty analysis reveals vertical errors are mostly dependent on the topographical slopes and maximum errors are concentrated on the steep channel banks and scarps. The planimetric analysis shows significant reworking of sediment occurred throughout the 72-year period from 1937 to 2009. Substantial amounts of HMS remobilization occurred during major flood

  9. A complete CAD system for pulmonary nodule detection in high resolution CT images

    NASA Astrophysics Data System (ADS)

    Zhang, Xiangwei; McLennan, Geoffrey; Hoffman, Eric A.; Sonka, Milan

    2005-04-01

    The purpose of this study is to develop a computer-aided diagnosis (CAD) system to detect small-sized (from 2mm to 10mm) pulmonary nodules in high resolution helical CT scans. A new CAD system is proposed to locate both juxtapleural nodules and non-pleural nodules. Isotropic resampling and lung segmentation are performed as preprocessing steps. Morphological closing was utilized to smooth the lung contours to include the indented possible juxtapleural locations, thresholding and 3D component analysis were used to obtain 3D volumetric nodule candidates; furthermore, gray level and geometric features were extracted, and analyzed using linear discriminant analysis (LDA) classifier. Leave one case out method was used to evaluate the LDA. To deal with non-pleural nodules, a discrete-time cellular neural network (DTCNN) based on local shape features was developed. This scheme employed the local shape property to perform voxel classification. The shape index feature successfully captured the local shape difference between nodules and non-nodules, especially vessels. To tailor it for lung nodule detection, this DTCNN was trained using genetic algorithms (GAs) to derive the shape index variation pattern of nodules. Nonoverlapping training and testing sets were utilized in the non-pleural nodule detection. 19 clinical thoracic CT cases involving a total of 4838 sectional images were used in this work. The juxtapleural nodule detection method was able to obtain sensitivity 81.25% with an average of 8.29 FPs per case. The non-pleural nodule finding scheme attained sensitivity of 83.9% with an average 3.47 FPs/case. Combining the two subsystems together, an overall performance of 82.98% sensitivity with 11.76 FPs/case can be obtained.

  10. Novel ultrahigh resolution optical fibre temperature sensor

    NASA Astrophysics Data System (ADS)

    Poeggel, Sven; Duraibabu, Dineshbabu; Dooly, Gerard; Lewis, Elfed; Leen, Gabriel

    2016-05-01

    In this paper a novel patent pending high resolution optical fibre temperature sensor, based on an optical fibre pressure and temperature sensor (OFTPS), which is surrounded by an oil filled chamber, is presented. The OFPTS is based on a Fabry Perot interferometer (FPI) which has an embedded fibre Bragg grating (FBG). The high ratio between the volume of the oil filled outer cavity and the FPIs air filled cavity, results in a highly sensitive temperature sensor. The FBG element of the device can be used for wide range temperature measurements, and combining this capability with the high resolution capability of the FPI/oil cavity results in a wide range and high resolution temperature sensing device. The outer diameter of the sensor is less than 1mm in diameter and can be designed to be even smaller. The sensors temperature response was measured in a range of ΔT = 7K and resulted in a shift in the optical spectrum of ΔλF = 61.42nm. Therefore the Q-point of the reflected optical FPI spectrum is shifting with a sensitivity of sot = 8.77 nm/K . The sensitivity can easily be further increased by changing the oil/air volumetric ratio and therefore adapt the sensor to a wide variety of applications.

  11. Water-level oscillations caused by volumetric and deviatoric dynamic strains

    NASA Astrophysics Data System (ADS)

    Shalev, Eyal; Kurzon, Ittai; Doan, Mai-Linh; Lyakhovsky, Vladimir

    2016-02-01

    Travelling seismic waves and Earth tides are known to cause oscillations in well water levels due to the volumetric strain characteristics of the ground motion. Although the response of well water levels to S and Love waves has been reported, it has not yet been quantified. In this paper we describe and explain the behaviour of a closed artesian water well (Gomè 1) in response to teleseismic earthquakes. This well is located within a major fault zone and screened at a highly damaged (cracked) sandstone layer. We adopt the original Skempton approach where both volumetric and deviatoric stresses (and strains) affect pore pressure. Skempton's coefficients < tex - mathid = "IM0001" > B and < tex - mathid = "IM0002" > A couple the volumetric and deviatoric stresses respectively with pore pressure and < tex - mathid = "IM0003" > BKu and < tex - mathid = "IM0004" > N are the equivalent coupling terms to volumetric and deviatoric strains. The water level in this well responds dramatically to volumetric strain (P and Rayleigh waves) as well as to deviatoric strain (S and Love waves). This response is explained by the nonlinear elastic behaviour of the highly damaged rocks. The water level response to deviatoric strain depends on the damage in the rock; deviatoric strain loading on damaged rock results in high water level amplitudes, and no response in undamaged rock. We find high values of < tex - mathid = "IM0005" > N= 8.5 GPa that corresponds to -0.5 < A < -0.25 expected at highly damaged rocks. We propose that the Gomè 1 well is located within fractured rocks, and therefore, dilatency is high, and the response of water pressure to deviatoric deformation is high. This analysis is supported by the agreement between the estimated compressibility of the aquifer, independently calculated from Earth tides, seismic response of the water pressure and other published data.

  12. Numerical Volumetric Analysis of Spatially Dependent Transmissivity and Storativity in Heterogeneous Aquifers

    NASA Astrophysics Data System (ADS)

    Rhode, K.; Osiensky, J.

    2005-12-01

    Aquifer transmissivity (T) and storativity (S) values control the rate and areal extent of propagation of the cone of depression from a pumped well. It has been documented recently that transmissivity and storativity, reflect the geometric and arithmetic means, respectively, of the area contacted by the cone of depression. However, these findings do not reflect a volumetric evaluation of the cone of depression within the heterogenities. Analysis of spatial, volumetric variations within the cone of depression expressed at the potentiometric surface, offers a more general solution to evaluate the meaning of T and S values. Log-normal and normal distributions of hydraulic conductivity as block heterogeneities were established within model domains for simulated aquifer tests. By analyzing the volumetric evolution of the cone of depression observed in the potentiometric surface, we are able to illustrate the averaging of transmissivity as a function of time, and distance from the pumping well for the entire affected aquifer. Volumetric analysis of simulated aquifer tests show an exponential decrease in the arithmetic, harmonic, and geometric weighted mean transmissivity within the evolving cone of depression through time, approaching steady, basin-wide averages. Transmissivity estimates derived for single observation wells by conventional testing methods (i.e., Theis, 1935; Cooper and Jacob, 1946) are found to increase with increasing radial distance from the pumping well. However, when the same observation well drawdown data are plotted together with, and constrained by, the drawdown curve for the pumping well, a family of drawdown curves is derived that yields transmissivity values that are consistent with the volumetric, weighted, mean transmissivity values calculated for the entire cone of depression for specific periods of time (i.e., areal extent).

  13. In vivo cellular imaging with microscopes enabled by MEMS scanners

    NASA Astrophysics Data System (ADS)

    Ra, Hyejun

    High-resolution optical imaging plays an important role in medical diagnosis and biomedical research. Confocal microscopy is a widely used imaging method for obtaining cellular and sub-cellular images of biological tissue in reflectance and fluorescence modes. Its characteristic optical sectioning capability also enables three-dimensional (3-D) image reconstruction. However, its use has mostly been limited to excised tissues due to the requirement of high numerical aperture (NA) lenses for cellular resolution. Microscope miniaturization can enable in vivo imaging to make possible early cancer diagnosis and biological studies in the innate environment. In this dissertation, microscope miniaturization for in vivo cellular imaging is presented. The dual-axes confocal (DAC) architecture overcomes limitations of the conventional single-axis confocal (SAC) architecture to allow for miniaturization with high resolution. A microelectromechanical systems (MEMS) scanner is the central imaging component that is key in miniaturization of the DAC architecture. The design, fabrication, and characterization of the two-dimensional (2-D) MEMS scanner are presented. The gimbaled MEMS scanner is fabricated on a double silicon-on-insulator (SOI) wafer and is actuated by self-aligned vertical electrostatic combdrives. The imaging performance of the MEMS scanner in a DAC configuration is shown in a breadboard microscope setup, where reflectance and fluorescence imaging is demonstrated. Then, the MEMS scanner is integrated into a miniature DAC microscope. The whole imaging system is integrated into a portable unit for research in small animal models of human biology and disease. In vivo 3-D imaging is demonstrated on mouse skin models showing gene transfer and siRNA silencing. The siRNA silencing process is sequentially imaged in one mouse over time.

  14. Volumetric LiDAR scanning of a wind turbine wake and comparison with a 3D analytical wake model

    NASA Astrophysics Data System (ADS)

    Carbajo Fuertes, Fernando; Porté-Agel, Fernando

    2016-04-01

    A correct estimation of the future power production is of capital importance whenever the feasibility of a future wind farm is being studied. This power estimation relies mostly on three aspects: (1) a reliable measurement of the wind resource in the area, (2) a well-established power curve of the future wind turbines and, (3) an accurate characterization of the wake effects; the latter being arguably the most challenging one due to the complexity of the phenomenon and the lack of extensive full-scale data sets that could be used to validate analytical or numerical models. The current project addresses the problem of obtaining a volumetric description of a full-scale wake of a 2MW wind turbine in terms of velocity deficit and turbulence intensity using three scanning wind LiDARs and two sonic anemometers. The characterization of the upstream flow conditions is done by one scanning LiDAR and two sonic anemometers, which have been used to calculate incoming vertical profiles of horizontal wind speed, wind direction and an approximation to turbulence intensity, as well as the thermal stability of the atmospheric boundary layer. The characterization of the wake is done by two scanning LiDARs working simultaneously and pointing downstream from the base of the wind turbine. The direct LiDAR measurements in terms of radial wind speed can be corrected using the upstream conditions in order to provide good estimations of the horizontal wind speed at any point downstream of the wind turbine. All this data combined allow for the volumetric reconstruction of the wake in terms of velocity deficit as well as turbulence intensity. Finally, the predictions of a 3D analytical model [1] are compared to the 3D LiDAR measurements of the wind turbine. The model is derived by applying the laws of conservation of mass and momentum and assuming a Gaussian distribution for the velocity deficit in the wake. This model has already been validated using high resolution wind-tunnel measurements

  15. Ct Anatomy of Buccal Fat Pad and its Role in Volumetric Alterations of Face

    NASA Astrophysics Data System (ADS)

    Guryanov, R. A.; Guryanov, A. S.

    2015-05-01

    The aim of our study is the revision of the anatomy of buccal fat pad and its role in a volumetric pattern of face. Bichat fat pad is a fatty anatomical structure with body and numerous process enclosed between the bony and muscular structures in temporal, pterygopalatine fossae and extents to the cheek area. Nevertheless, the opinion about its structure and role in forming of volume pattern of face sometimes could be controversial. The Bichat fat pad consists on predominately hormone insensitive fat tissue with underdeveloped stroma, this leads to the stability of the fat pad volume and lesser radiodensity in contrast to the subcutaneous fat. Moreover, the buccal fat pad is delimited from the subcutaneous fat of cheek area by the strong capsule. This feature allows us to use CT to divide the Bichat fat pad from the surrounding tissues. The thorough embryological data provide the distinction of Bichat fat pad from the subcutaneous fat of cheek area even at the stage of development. On the other hand, the border between the masticatory muscles and the processes of the fat pad is not evident and resembles cellular spaces in the other anatomical areas. To elicit the role of the buccal fat pad in volume pattern of face and its function we have performed the several experiments, analyzed the postoperative results after Bichat fat pad resection using surface scanner and CT data. At first, we have performed the gravity test: the patient's face photogrammetry scanning in horizontal and vertical position of head and it revealed the excess of volume in temporal area in horizontal position. To exclude mechanism of overflowing of the skin and subcutaneous fat over the zygomatic arch we have placed the markers on the skin surface at the different areas of face including the projection of ligaments and found out that the migration of soft tissue over the zygomatic arch is about 3-5 mm and almost the same in temporal area. However, the acquired result was unsatisfying because

  16. Thermodynamics of cellular statistical inference

    NASA Astrophysics Data System (ADS)

    Lang, Alex; Fisher, Charles; Mehta, Pankaj

    2014-03-01

    Successful organisms must be capable of accurately sensing the surrounding environment in order to locate nutrients and evade toxins or predators. However, single cell organisms face a multitude of limitations on their accuracy of sensing. Berg and Purcell first examined the canonical example of statistical limitations to cellular learning of a diffusing chemical and established a fundamental limit to statistical accuracy. Recent work has shown that the Berg and Purcell learning limit can be exceeded using Maximum Likelihood Estimation. Here, we recast the cellular sensing problem as a statistical inference problem and discuss the relationship between the efficiency of an estimator and its thermodynamic properties. We explicitly model a single non-equilibrium receptor and examine the constraints on statistical inference imposed by noisy biochemical networks. Our work shows that cells must balance sample number, specificity, and energy consumption when performing statistical inference. These tradeoffs place significant constraints on the practical implementation of statistical estimators in a cell.

  17. Optofluidic Detection for Cellular Phenotyping

    PubMed Central

    Tung, Yi-Chung; Huang, Nien-Tsu; Oh, Bo-Ram; Patra, Bishnubrata; Pan, Chi-Chun; Qiu, Teng; Paul, K. Chu; Zhang, Wenjun; Kurabayashi, Katsuo

    2012-01-01

    Quantitative analysis of the output of processes and molecular interactions within a single cell is highly critical to the advancement of accurate disease screening and personalized medicine. Optical detection is one of the most broadly adapted measurement methods in biological and clinical assays and serves cellular phenotyping. Recently, microfluidics has obtained increasing attention due to several advantages, such as small sample and reagent volumes, very high throughput, and accurate flow control in the spatial and temporal domains. Optofluidics, which is the attempt to integrate optics with microfluidic, shows great promise to enable on-chip phenotypic measurements with high precision, sensitivity, specificity, and simplicity. This paper reviews the most recent developments of optofluidic technologies for cellular phenotyping optical detection. PMID:22854915

  18. Hox Targets and Cellular Functions

    PubMed Central

    Sánchez-Herrero, Ernesto

    2013-01-01

    Hox genes are a group of genes that specify structures along the anteroposterior axis in bilaterians. Although in many cases they do so by modifying a homologous structure with a different (or no) Hox input, there are also examples of Hox genes constructing new organs with no homology in other regions of the body. Hox genes determine structures though the regulation of targets implementing cellular functions and by coordinating cell behavior. The genetic organization to construct or modify a certain organ involves both a genetic cascade through intermediate transcription factors and a direct regulation of targets carrying out cellular functions. In this review I discuss new data from genome-wide techniques, as well as previous genetic and developmental information, to describe some examples of Hox regulation of different cell functions. I also discuss the organization of genetic cascades leading to the development of new organs, mainly using Drosophila melanogaster as the model to analyze Hox function. PMID:24490109

  19. Peroxisome Metabolism and Cellular Aging

    PubMed Central

    Titorenko, Vladimir I.; Terlecky, Stanley R.

    2010-01-01

    The essential role of peroxisomes in fatty acid oxidation, anaplerotic metabolism, and hydrogen peroxide turnover is well established. Recent findings suggest these and other related biochemical processes governed by the organelle may also play a critical role in regulating cellular aging. The goal of this review is to summarize and integrate into a model, the evidence that peroxisome metabolism actually helps define the replicative and chronological age of a eukaryotic cell. In this model, peroxisomal reactive oxygen species (ROS) are seen as altering organelle biogenesis and function, and eliciting changes in the dynamic communication networks that exist between peroxisomes and other cellular compartments. At low levels, peroxisomal ROS activate an anti-aging program in the cell; at concentrations beyond a specific threshold, a pro-aging course is triggered. PMID:21083858

  20. Cellular solidification of transparent monotectics

    NASA Technical Reports Server (NTRS)

    Kaulker, W. F.

    1986-01-01

    Understanding how liquid phase particles are engulfed or pushed during freezing of a monotectic is addressed. The additional complication is that the solid-liquid interface is nonplanar due to constitutional undercooling. Some evidence of particle pushing where the particles are the liquid phase of the montectic was already observed. Cellular freezing of the succinonitrile-glycerol system also occurred. Only a few compositions were tested at that time. The starting materials were not especially pure so that cellular interface observed was likely due to the presence of unkown impurities, the major portion of which was water. Topics addressed include: the effort of modeling the particle pushing process using the computer, establishing an apparatus for the determination of phase diagrams, and the measurement of the temperature gradients with a specimen which will solidify on the temperature gradient microscope stage.

  1. Xtoys: Cellular automata on xwindows

    SciTech Connect

    Creutz, M.

    1995-08-15

    Xtoys is a collection of xwindow programs for demonstrating simulations of various statistical models. Included are xising, for the two dimensional Ising model, xpotts, for the q-state Potts model, xautomalab, for a fairly general class of totalistic cellular automata, xsand, for the Bak-Tang-Wiesenfield model of self organized criticality, and xfires, a simple forest fire simulation. The programs should compile on any machine supporting xwindows.

  2. High-Resolution Intravital Microscopy

    PubMed Central

    Andresen, Volker; Pollok, Karolin; Rinnenthal, Jan-Leo; Oehme, Laura; Günther, Robert; Spiecker, Heinrich; Radbruch, Helena; Gerhard, Jenny; Sporbert, Anje; Cseresnyes, Zoltan; Hauser, Anja E.; Niesner, Raluca

    2012-01-01

    Cellular communication constitutes a fundamental mechanism of life, for instance by permitting transfer of information through synapses in the nervous system and by leading to activation of cells during the course of immune responses. Monitoring cell-cell interactions within living adult organisms is crucial in order to draw conclusions on their behavior with respect to the fate of cells, tissues and organs. Until now, there is no technology available that enables dynamic imaging deep within the tissue of living adult organisms at sub-cellular resolution, i.e. detection at the level of few protein molecules. Here we present a novel approach called multi-beam striped-illumination which applies for the first time the principle and advantages of structured-illumination, spatial modulation of the excitation pattern, to laser-scanning-microscopy. We use this approach in two-photon-microscopy - the most adequate optical deep-tissue imaging-technique. As compared to standard two-photon-microscopy, it achieves significant contrast enhancement and up to 3-fold improved axial resolution (optical sectioning) while photobleaching, photodamage and acquisition speed are similar. Its imaging depth is comparable to multifocal two-photon-microscopy and only slightly less than in standard single-beam two-photon-microscopy. Precisely, our studies within mouse lymph nodes demonstrated 216% improved axial and 23% improved lateral resolutions at a depth of 80 µm below the surface. Thus, we are for the first time able to visualize the dynamic interactions between B cells and immune complex deposits on follicular dendritic cells within germinal centers (GCs) of live mice. These interactions play a decisive role in the process of clonal selection, leading to affinity maturation of the humoral immune response. This novel high-resolution intravital microscopy method has a huge potential for numerous applications in neurosciences, immunology, cancer research and developmental biology

  3. Competitive potential of cellular mobile telecommunications

    SciTech Connect

    Ware, H.

    1983-02-03

    The Federal Communications Commission (FCC) has recently issued rules for the commercial operation of a telecommunications technology not previously in commercial use: the cellular mobile radio. The author has carefully considered the potential for competition between cellular systems and for competition between cellular radio and alternative communications technologies under the regulatory scheme which has been adopted by the FCC. He finds that competition between cellular and wire-line services can be viable if cellular cost and demand data are carefully tracked to avoid market congestion and if cellular or other techniques are not allowed to undercut selected local exchange rates.

  4. Multibeam Bathymetry to Measure Volumetric Change and Particle Size Distributions in the Snake River through Hells Canyon

    NASA Astrophysics Data System (ADS)

    Anderson, K.; Morehead, M. D.; Anderson, K.; Wilson, T.; Butler, M.; Conner, J. T.; Hocker, B.

    2011-12-01

    -bound section of the Snake River. Since 2008, Idaho Power has been collecting high-resolution multibeam bathymetry to generate a continuous bathymetric surface through Hells Canyon to use as a baseline. Data were collected using RTK-GPS positioning and a MBB sonar unit mounted to a 9 m long jetboat during spring high water conditions. Areas of survey overlap within and between years have shown limited areas of dramatic changes in storage (meters of change over a few days to years). Data collected during the MBB surveys (elevation, backscatter, snippets, and derivative data products) have been used to create preliminary maps of particle size distribution after calibration with point measurements of the bed surface D50 from historic underwater imagery. This baseline survey will be compared to future surveys in selected reaches to measure volumetric changes of sediment stored on the riverbed. Future work will focus on statistical differencing of bathymetric surfaces to categorize areas of accumulation, deposition, and no measurable change and improved particle size mapping with calibration with current underwater video images to be collected in the fall of 2011.

  5. Levitational Image Cytometry with Temporal Resolution.

    PubMed

    Tasoglu, Savas; Khoory, Joseph A; Tekin, Huseyin C; Thomas, Clemence; Karnoub, Antoine E; Ghiran, Ionita C; Demirci, Utkan

    2015-07-01

    A simple, yet powerful magnetic-levitation-based device is reported for real-time, label-free separation, as well as high-resolution monitoring of cell populations based on their unique magnetic and density signatures. This method allows a wide variety of cellular processes to be studied, accompanied by transient or permanent changes in cells' fundamental characteristics as a biological material. PMID:26058598

  6. Use of volumetric features for temporal comparison of mass lesions in full field digital mammograms

    SciTech Connect

    Bozek, Jelena Grgic, Mislav; Kallenberg, Michiel; Karssemeijer, Nico

    2014-02-15

    Purpose: Temporal comparison of lesions might improve classification between benign and malignant lesions in full-field digital mammograms (FFDM). The authors compare the use of volumetric features for lesion classification, which are computed from dense tissue thickness maps, to the use of mammographic lesion area. Use of dense tissue thickness maps for lesion characterization is advantageous, since it results in lesion features that are invariant to acquisition parameters. Methods: The dataset used in the analysis consisted of 60 temporal mammogram pairs comprising 120 mediolateral oblique or craniocaudal views with a total of 65 lesions, of which 41 were benign and 24 malignant. The authors analyzed the performance of four volumetric features, area, and four other commonly used features obtained from temporal mammogram pairs, current mammograms, and prior mammograms. The authors evaluated the individual performance of all features and of different feature sets. The authors used linear discriminant analysis with leave-one-out cross validation to classify different feature sets. Results: Volumetric features from temporal mammogram pairs achieved the best individual performance, as measured by the area under the receiver operating characteristic curve (A{sub z} value). Volume change (A{sub z} = 0.88) achieved higher A{sub z} value than projected lesion area change (A{sub z} = 0.78) in the temporal comparison of lesions. Best performance was achieved with a set that consisted of a set of features extracted from the current exam combined with four volumetric features representing changes with respect to the prior mammogram (A{sub z} = 0.90). This was significantly better (p = 0.005) than the performance obtained using features from the current exam only (A{sub z} = 0.77). Conclusions: Volumetric features from temporal mammogram pairs combined with features from the single exam significantly improve discrimination of benign and malignant lesions in FFDM mammograms

  7. Development of a simplified asphalt mix stability procedure for use in Superpave volumetric mix design

    NASA Astrophysics Data System (ADS)

    Hafez, Ihab Hussein Fahmy

    Over the last five decades, two common test methods (Marshall and Hveem) have evolved for the design of asphaltic mixes. These design methods have been historically found to be generally reliable and reasonable for most application in design. However, premature distress in many flexible pavements suggests that these empirical methods of design do not guarantee a stable mix. Recently, many studies have been carried out in order to develop a rational mix design procedure that accounts for both the mix volumetric properties as well as fundamental engineering properties. Among those is the Superpave design procedure, which was originally divided into three, hierarchical levels termed the volumetric mix design (level I), the abbreviated mix design (level II), and the full mix design (level III). In the volumetric design, the entire mix design process is based upon the volumetric properties and does not include a test method to evaluate the stability/strength of the mix. Although both the abbreviated level and the full level of design included test methods that considered the engineering properties in a complete and a comprehensive manner; they required the purchase of very expensive equipment and a large number of samples to be tested. The objective of this research was to develop a new rational "fundamental" mix strength (stability) test for the design of dense graded mixes to overcome the limitations of the Hveem and Marshall empirical methods and to fill the gaps and major deficiencies in the current Superpave volumetric mix design. The new procedure is based upon the Superpave volumetric design (level I) but is augmented by the simple, but fundamental mix strength (stability) test. Such a test is now currently absent in the existing Superpave approach. The new procedure introduces the flow time as a fundamental engineering design criterion in the mix design. This parameter is defined as the time (in seconds) at which plastic flow in a mix occurs under creep loading

  8. Is there Link between the Type of the Volumetric Strain Curve and Elastic Constants, Porosity, Stress and Strain Characteristics ?

    NASA Astrophysics Data System (ADS)

    Palchik, V.

    2013-03-01

    The stress [crack damage stress ( σ cd) and uniaxial compressive strength ( σ c)] and strain characteristics [maximum total volumetric strain ( ɛ cd), axial failure strain ( ɛ af)], porosity ( n) and elastic constants [elastic modulus ( E) and Poisson's ratio ( ν)] and their ratios were coordinated with the existence of two different types (type 1 and type 2) of volumetric strain curve. Type 1 volumetric strain curve has a reversal point and, therefore, σ cd is less than the uniaxial compressive strength ( σ c). Type 2 has no reversal point, and the bulk volume of rock decreases until its failure occurs (i.e., σ cd = σ c). It is confirmed that the ratio between the elastic modulus ( E) and the parameter λ = n/ ɛ cd strongly affects the crack damage stress ( σ cd) for both type 1 and type 2 volumetric strain curves. It is revealed that heterogeneous carbonate rock samples exhibit different types of the volumetric strain curve even within the same rock formation, and the range of σ cd/ σ c = 0.54-1 for carbonate rocks is wider than the range (0.71 < σ cd/ σ c < 0.84) obtained by other researchers for granites, sandstones and quartzite. It is established that there is no connection between the type of the volumetric strain curve and values of n, E, σ cd, ν, E/(1 - 2 ν), M R = E/ σ c and E/ λ. On the other hand, the type of volumetric strain curve is connected with the values of λ and the ratio between the axial failure strain ( ɛ af) and the maximum total volumetric strain ( ɛ cd). It is argued that in case of small ɛ af/ ɛ cd-small λ, volumetric strain curve follows the type 2.

  9. Coordination of Cellular Dynamics Contributes to Tooth Epithelium Deformations.

    PubMed

    Morita, Ritsuko; Kihira, Miho; Nakatsu, Yousuke; Nomoto, Yohei; Ogawa, Miho; Ohashi, Kazumasa; Mizuno, Kensaku; Tachikawa, Tetsuhiko; Ishimoto, Yukitaka; Morishita, Yoshihiro; Tsuji, Takashi

    2016-01-01

    The morphologies of ectodermal organs are shaped by appropriate combinations of several deformation modes, such as invagination and anisotropic tissue elongation. However, how multicellular dynamics are coordinated during deformation processes remains to be elucidated. Here, we developed a four-dimensional (4D) analysis system for tracking cell movement and division at a single-cell resolution in developing tooth epithelium. The expression patterns of a Fucci probe clarified the region- and stage-specific cell cycle patterns within the tooth germ, which were in good agreement with the pattern of the volume growth rate estimated from tissue-level deformation analysis. Cellular motility was higher in the regions with higher growth rates, while the mitotic orientation was significantly biased along the direction of tissue elongation in the epithelium. Further, these spatio-temporal patterns of cellular dynamics and tissue-level deformation were highly correlated with that of the activity of cofilin, which is an actin depolymerization factor, suggesting that the coordination of cellular dynamics via actin remodeling plays an important role in tooth epithelial morphogenesis. Our system enhances the understanding of how cellular behaviors are coordinated during ectodermal organogenesis, which cannot be observed from histological analyses. PMID:27588418

  10. Thermal effects of radiation from cellular telephones

    NASA Astrophysics Data System (ADS)

    Wainwright, Peter

    2000-08-01

    A finite element thermal model of the head has been developed to calculate temperature rises generated in the brain by radiation from cellular telephones and similar electromagnetic devices. A 1 mm resolution MRI dataset was segmented semiautomatically, assigning each volume element to one of ten tissue types. A finite element mesh was then generated using a fully automatic tetrahedral mesh generator developed at NRPB. There are two sources of heat in the model: firstly the natural metabolic heat production; and secondly the power absorbed from the electromagnetic field. The SAR was derived from a finite difference time domain model of the head, coupled to a model `mobile phone', namely a quarter-wavelength antenna mounted on a metal box. The steady-state temperature distribution was calculated using the standard Pennes `bioheat equation'. In the normal cerebral cortex the high blood perfusion rate serves to provide an efficient cooling mechanism. In the case of equipment generally available to the public, the maximum temperature rise found in the brain was about 0.1 °C. These results will help in the further development of criteria for exposure guidelines, and the technique developed may be used to assess temperature rises associated with SARs for different types of RF exposure.

  11. Magnetic tweezers microscope for cellular manipulation

    NASA Astrophysics Data System (ADS)

    Dong, Chen-Yuan; Huang, Hayden; Sutin, Jason D. B.; Kwon, Hyuk-Sang; Cragg, George E.; Gilbert, R.; Lee, Richard T.; Gratton, Enrico; Kamm, Roger D.; Lauffenburger, Douglas A.; So, Peter T. C.

    2000-04-01

    We present the design of a magnetic tweezers microscope for cellular manipulation. Our design allows versatile and significant 3D stress application over a large sample region. For linear force application, forces up to 250 pN per 4.5 micrometers magnetic bead can be applied. Finite element analysis shows that variance in force level is around 10 percent within an area of 300 X 300 micrometers 2. Our eight-pole design potentially allows 3D liner force application and exertion of torsional stress. Furthermore, our design allows high resolution imaging using high numerical aperture objective. Both finite element analysis of magnetic field distribution and force calibration of our design are presented. As a feasibility study, we incubated fibronectin coated 4.5 micrometers polystyrene beads with Swiss 3T3 mouse fibroblast cells. Under application around 250 pN of force per magnetic particle, we observed relative movement between attached magnetic and polystyrene beads to be on the order of 1 micrometers . Elastic, viscoelastic, and creeping responses of cell surfaces were observed. Our results are consistent with previous observations using similar magnetic techniques.

  12. Cellular immune responses to HIV

    NASA Astrophysics Data System (ADS)

    McMichael, Andrew J.; Rowland-Jones, Sarah L.

    2001-04-01

    The cellular immune response to the human immunodeficiency virus, mediated by T lymphocytes, seems strong but fails to control the infection completely. In most virus infections, T cells either eliminate the virus or suppress it indefinitely as a harmless, persisting infection. But the human immunodeficiency virus undermines this control by infecting key immune cells, thereby impairing the response of both the infected CD4+ T cells and the uninfected CD8+ T cells. The failure of the latter to function efficiently facilitates the escape of virus from immune control and the collapse of the whole immune system.

  13. Quantum cellular automata without particles

    NASA Astrophysics Data System (ADS)

    Meyer, David A.; Shakeel, Asif

    2016-01-01

    Quantum cellular automata (QCA) constitute space and time homogeneous discrete models for quantum field theories (QFTs). Although QFTs are defined without reference to particles, computations are done in terms of Feynman diagrams, which are explicitly interpreted in terms of interacting particles. Similarly, the easiest QCA to construct are quantum lattice gas automata (QLGA). A natural question then is, which QCA are not QLGA? Here we construct a nontrivial example of such a QCA; it provides a simple model in 1 +1 dimensions with no particle interpretation at the scale where the QCA dynamics are homogeneous.

  14. Universal map for cellular automata

    NASA Astrophysics Data System (ADS)

    García-Morales, V.

    2012-08-01

    A universal map is derived for all deterministic 1D cellular automata (CAs) containing no freely adjustable parameters and valid for any alphabet size and any neighborhood range (including non-symmetrical neighborhoods). The map can be extended to an arbitrary number of dimensions and topologies and to arbitrary order in time. Specific CA maps for the famous Conway's Game of Life and Wolfram's 256 elementary CAs are given. An induction method for CAs, based in the universal map, allows mathematical expressions for the orbits of a wide variety of elementary CAs to be systematically derived.

  15. Therapeutic cloning and cellular reprogramming.

    PubMed

    Rodriguez, Ramon M; Ross, Pablo J; Cibelli, Jose B

    2012-01-01

    Embryonic stem cells are capable of differentiating into any cell-type present in an adult organism, and constitute a renewable source of tissue for regenerative therapies. The transplant of allogenic stem cells is challenging due to the risk of immune rejection. Nevertheless, somatic cell reprogramming techniques allow the generation of isogenic embryonic stem cells, genetically identical to the patient. In this chapter we will discuss the cellular reprogramming techniques in the context of regenerative therapy and the biological and technical barriers that they will need to overcome before clinical use. PMID:22457116

  16. Symmetry analysis of cellular automata

    NASA Astrophysics Data System (ADS)

    García-Morales, V.

    2013-01-01

    By means of B-calculus [V. García-Morales, Phys. Lett. A 376 (2012) 2645] a universal map for deterministic cellular automata (CAs) has been derived. The latter is shown here to be invariant upon certain transformations (global complementation, reflection and shift). When constructing CA rules in terms of rules of lower range a new symmetry, “invariance under construction” is uncovered. Modular arithmetic is also reformulated within B-calculus and a new symmetry of certain totalistic CA rules, which calculate the Pascal simplices modulo an integer number p, is then also uncovered.

  17. Primitive control of cellular metabolism

    NASA Technical Reports Server (NTRS)

    Mitz, M. A.

    1974-01-01

    It is pointed out that control substances must have existed from the earliest times in the evolution of life and that the same control mechanisms must exist today. The investigation reported is concerned with the concept that carbon dioxide is a primitive regulator of cell function. The effects of carbon dioxide on cellular materials are examined, taking into account questions of solubilization, dissociation, changes of charge, stabilization, structural changes, wettability, the exclusion of other gases, the activation of compounds, changes in plasticity, and changes in membrane permeability.

  18. The Cellular Basis of Aging

    PubMed Central

    Scoggin, Charles H.

    1981-01-01

    Normal cells have only a finite life span before they die. The process known as aging may occur as a result of continued damage to the cell or as a result of expression of predetermined information within the genetic structure of the cell. Both processes lead to progressive cellular dysfunction which is evidenced by the organs of the body as aging. By understanding how individual cells age we will gain insight into how the body as a whole ages. The impact of such knowledge on science and society is a matter of both conjecture and concern. PMID:7336718

  19. Protein accounting in the cellular economy

    PubMed Central

    Vázquez-Laslop, Nora; Mankin, Alexander S.

    2014-01-01

    Knowing the copy number of cellular proteins is critical for understanding cell physiology. By being able to measure the absolute synthesis rates of the majority of cellular proteins, Li et al. (2014) gain insights into key aspects of translation regulation and fundamental principles of cellular strategies to adjust protein synthesis according to the needs. PMID:24766801

  20. Protein accounting in the cellular economy.

    PubMed

    Vázquez-Laslop, Nora; Mankin, Alexander S

    2014-04-24

    Knowing the copy number of cellular proteins is critical for understanding cell physiology. By being able to measure the absolute synthesis rates of the majority of cellular proteins, Li et al. gain insights into key aspects of translation regulation and fundamental principles of cellular strategies to adjust protein synthesis according to the functional needs. PMID:24766801