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Sample records for tissue phase mapping

  1. Magnetic resonance tissue phase mapping demonstrates altered left ventricular diastolic function in children with chronic kidney disease

    International Nuclear Information System (INIS)

    Gimpel, Charlotte; Pohl, Martin; Jung, Bernd A.; Jung, Sabine; Brado, Johannes; Odening, Katja E.; Schwendinger, Daniel; Burkhardt, Barbara; Geiger, Julia; Arnold, Raoul

    2017-01-01

    Echocardiographic examinations have revealed functional cardiac abnormalities in children with chronic kidney disease. To assess the feasibility of MRI tissue phase mapping in children and to assess regional left ventricular wall movements in children with chronic kidney disease. Twenty pediatric patients with chronic kidney disease (before or after renal transplantation) and 12 healthy controls underwent tissue phase mapping (TPM) to quantify regional left ventricular function through myocardial long (Vz) and short-axis (Vr) velocities at all 3 levels of the left ventricle. Patients and controls (age: 8 years - 20 years) were matched for age, height, weight, gender and heart rate. Patients had higher systolic blood pressure. No patient had left ventricular hypertrophy on MRI or diastolic dysfunction on echocardiography. Fifteen patients underwent tissue Doppler echocardiography, with normal z-scores for mitral early diastolic (V E ), late diastolic (V A ) and peak systolic (V S ) velocities. Throughout all left ventricular levels, peak diastolic Vz and Vr (cm/s) were reduced in patients: Vz base -10.6 ± 1.9 vs. -13.4 ± 2.0 (P < 0.0003), Vz mid -7.8 ± 1.6 vs. -11 ± 1.5 (P < 0.0001), Vz apex -3.8 ± 1.6 vs. -5.3 ± 1.6 (P = 0.01), Vr base -4.2 ± 0.8 vs. -4.9 ± 0.7 (P = 0.01), Vr mid -4.7 ± 0.7 vs. -5.4 ± 0.7 (P = 0.01), Vr apex -4.7 ± 1.4 vs. -5.6 ± 1.1 (P = 0.05). Tissue phase mapping is feasible in children and adolescents. Children with chronic kidney disease show significantly reduced peak diastolic long- and short-axis left ventricular wall velocities, reflecting impaired early diastolic filling. Thus, tissue phase mapping detects chronic kidney disease-related functional myocardial changes before overt left ventricular hypertrophy or echocardiographic diastolic dysfunction occurs. (orig.)

  2. Magnetic resonance tissue phase mapping demonstrates altered left ventricular diastolic function in children with chronic kidney disease

    Energy Technology Data Exchange (ETDEWEB)

    Gimpel, Charlotte; Pohl, Martin [Medical Center - University of Freiburg, Department of General Pediatrics, Adolescent Medicine and Neonatology, Center for Pediatrics, Freiburg (Germany); Jung, Bernd A. [Inselspital Bern, Institute of Diagnostic, Interventional and Pediatric Radiology, Bern (Switzerland); Jung, Sabine [Medical Center - University of Freiburg, Department of Nuclear Medicine, Freiburg (Germany); Brado, Johannes; Odening, Katja E. [University Heart Center Freiburg, Department of Cardiology and Angiology I, Freiburg (Germany); Schwendinger, Daniel [University Children' s Hospital Zurich, Zurich (Switzerland); Burkhardt, Barbara [University Children' s Hospital Zurich, Pediatric Heart Center, Zurich (Switzerland); Geiger, Julia [University Children' s Hospital Zurich, Department of Radiology, Zurich (Switzerland); Northwestern University, Department of Radiology, Chicago, IL (United States); Arnold, Raoul [University Hospital Heidelberg, Department of Pediatric and Congenital Cardiology, Heidelberg (Germany)

    2017-02-15

    Echocardiographic examinations have revealed functional cardiac abnormalities in children with chronic kidney disease. To assess the feasibility of MRI tissue phase mapping in children and to assess regional left ventricular wall movements in children with chronic kidney disease. Twenty pediatric patients with chronic kidney disease (before or after renal transplantation) and 12 healthy controls underwent tissue phase mapping (TPM) to quantify regional left ventricular function through myocardial long (Vz) and short-axis (Vr) velocities at all 3 levels of the left ventricle. Patients and controls (age: 8 years - 20 years) were matched for age, height, weight, gender and heart rate. Patients had higher systolic blood pressure. No patient had left ventricular hypertrophy on MRI or diastolic dysfunction on echocardiography. Fifteen patients underwent tissue Doppler echocardiography, with normal z-scores for mitral early diastolic (V{sub E}), late diastolic (V{sub A}) and peak systolic (V{sub S}) velocities. Throughout all left ventricular levels, peak diastolic Vz and Vr (cm/s) were reduced in patients: Vz{sub base} -10.6 ± 1.9 vs. -13.4 ± 2.0 (P < 0.0003), Vz{sub mid} -7.8 ± 1.6 vs. -11 ± 1.5 (P < 0.0001), Vz{sub apex} -3.8 ± 1.6 vs. -5.3 ± 1.6 (P = 0.01), Vr{sub base} -4.2 ± 0.8 vs. -4.9 ± 0.7 (P = 0.01), Vr{sub mid} -4.7 ± 0.7 vs. -5.4 ± 0.7 (P = 0.01), Vr{sub apex} -4.7 ± 1.4 vs. -5.6 ± 1.1 (P = 0.05). Tissue phase mapping is feasible in children and adolescents. Children with chronic kidney disease show significantly reduced peak diastolic long- and short-axis left ventricular wall velocities, reflecting impaired early diastolic filling. Thus, tissue phase mapping detects chronic kidney disease-related functional myocardial changes before overt left ventricular hypertrophy or echocardiographic diastolic dysfunction occurs. (orig.)

  3. Quantitative Susceptibility Mapping of Human Brain Reflects Spatial Variation in Tissue Composition

    Science.gov (United States)

    Li, Wei; Wu, Bing; Liu, Chunlei

    2011-01-01

    Image phase from gradient echo MRI provides a unique contrast that reflects brain tissue composition variations, such as iron and myelin distribution. Phase imaging is emerging as a powerful tool for the investigation of functional brain anatomy and disease diagnosis. However, the quantitative value of phase is compromised by its nonlocal and orientation dependent properties. There is an increasing need for reliable quantification of magnetic susceptibility, the intrinsic property of tissue. In this study, we developed a novel and accurate susceptibility mapping method that is also phase-wrap insensitive. The proposed susceptibility mapping method utilized two complementary equations: (1) the Fourier relationship of phase and magnetic susceptibility; and (2) the first-order partial derivative of the first equation in the spatial frequency domain. In numerical simulation, this method reconstructed the susceptibility map almost free of streaking artifact. Further, the iterative implementation of this method allowed for high quality reconstruction of susceptibility maps of human brain in vivo. The reconstructed susceptibility map provided excellent contrast of iron-rich deep nuclei and white matter bundles from surrounding tissues. Further, it also revealed anisotropic magnetic susceptibility in brain white matter. Hence, the proposed susceptibility mapping method may provide a powerful tool for the study of brain physiology and pathophysiology. Further elucidation of anisotropic magnetic susceptibility in vivo may allow us to gain more insight into the white matter microarchitectures. PMID:21224002

  4. Observation of human tissue with phase-contrast x-ray computed tomography

    Science.gov (United States)

    Momose, Atsushi; Takeda, Tohoru; Itai, Yuji; Tu, Jinhong; Hirano, Keiichi

    1999-05-01

    Human tissues obtained from cancerous kidneys fixed in formalin were observed with phase-contrast X-ray computed tomography (CT) using 17.7-keV synchrotron X-rays. By measuring the distributions of the X-ray phase shift caused by samples using an X-ray interferometer, sectional images that map the distribution of the refractive index were reconstructed. Because of the high sensitivity of phase- contrast X-ray CT, a cancerous lesion was differentiated from normal tissue and a variety of other structures were revealed without the need for staining.

  5. Absence of rotational activity detected using 2-dimensional phase mapping in the corresponding 3-dimensional phase maps in human persistent atrial fibrillation.

    Science.gov (United States)

    Pathik, Bhupesh; Kalman, Jonathan M; Walters, Tomos; Kuklik, Pawel; Zhao, Jichao; Madry, Andrew; Sanders, Prashanthan; Kistler, Peter M; Lee, Geoffrey

    2018-02-01

    Current phase mapping systems for atrial fibrillation create 2-dimensional (2D) maps. This process may affect the accurate detection of rotors. We developed a 3-dimensional (3D) phase mapping technique that uses the 3D locations of basket electrodes to project phase onto patient-specific left atrial 3D surface anatomy. We sought to determine whether rotors detected in 2D phase maps were present at the corresponding time segments and anatomical locations in 3D phase maps. One-minute left atrial atrial fibrillation recordings were obtained in 14 patients using the basket catheter and analyzed off-line. Using the same phase values, 2D and 3D phase maps were created. Analysis involved determining the dominant propagation patterns in 2D phase maps and evaluating the presence of rotors detected in 2D phase maps in the corresponding 3D phase maps. Using 2D phase mapping, the dominant propagation pattern was single wavefront (36.6%) followed by focal activation (34.0%), disorganized activity (23.7%), rotors (3.3%), and multiple wavefronts (2.4%). Ten transient rotors were observed in 9 of 14 patients (64%). The mean rotor duration was 1.1 ± 0.7 seconds. None of the 10 rotors observed in 2D phase maps were seen at the corresponding time segments and anatomical locations in 3D phase maps; 4 of 10 corresponded with single wavefronts in 3D phase maps, 2 of 10 with 2 simultaneous wavefronts, 1 of 10 with disorganized activity, and in 3 of 10 there was no coverage by the basket catheter at the corresponding 3D anatomical location. Rotors detected in 2D phase maps were not observed in the corresponding 3D phase maps. These findings may have implications for current systems that use 2D phase mapping. Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  6. Effects of white matter microstructure on phase and susceptibility maps.

    Science.gov (United States)

    Wharton, Samuel; Bowtell, Richard

    2015-03-01

    To investigate the effects on quantitative susceptibility mapping (QSM) and susceptibility tensor imaging (STI) of the frequency variation produced by the microstructure of white matter (WM). The frequency offsets in a WM tissue sample that are not explained by the effect of bulk isotropic or anisotropic magnetic susceptibility, but rather result from the local microstructure, were characterized for the first time. QSM and STI were then applied to simulated frequency maps that were calculated using a digitized whole-brain, WM model formed from anatomical and diffusion tensor imaging data acquired from a volunteer. In this model, the magnitudes of the frequency contributions due to anisotropy and microstructure were derived from the results of the tissue experiments. The simulations suggest that the frequency contribution of microstructure is much larger than that due to bulk effects of anisotropic magnetic susceptibility. In QSM, the microstructure contribution introduced artificial WM heterogeneity. For the STI processing, the microstructure contribution caused the susceptibility anisotropy to be significantly overestimated. Microstructure-related phase offsets in WM yield artifacts in the calculated susceptibility maps. If susceptibility mapping is to become a robust MRI technique, further research should be carried out to reduce the confounding effects of microstructure-related frequency contributions. © 2014 Wiley Periodicals, Inc.

  7. Pig-MAP, porcine acute phase proteins and standardisation of assays in Europe

    DEFF Research Database (Denmark)

    Alava, M.A.; Gonzalez-Ramon, N.; Heegaard, Peter M. H.

    1997-01-01

    The pattern of plasma proteins changes greatly following infection, inflammation or tissue injury. The concentration of some proteins referred to as acute phase proteins (APPs) significantly increases within hours or days after the onset of these processes. In contrast, the concentration of other...... during the inflammation. In addition to CRP and Hp, a serum alpha(2)-globulin was observed to be the major acute phase (MAP) protein in pigs. Pig-MAP is a new mammalian plasma protein, which is the pig counterpart of a recently cloned human serum protein denominated PK-120 or MRP. Pig-MAP shows promise...... for the presence of infectious, inflammatory and pathological lesions in animals. The ability to monitor the APP concentration in serum of pigs will improve the quality and safety of the meat produced as well as provide important diagnostic information for animal health and welfare. The serum concentration of APP...

  8. Tissue-based map of the human proteome

    DEFF Research Database (Denmark)

    Uhlén, Mathias; Fagerberg, Linn; Hallström, Björn M.

    2015-01-01

    Resolving the molecular details of proteome variation in the different tissues and organs of the human body will greatly increase our knowledge of human biology and disease. Here, we present a map of the human tissue proteome based on an integrated omics approach that involves quantitative transc...

  9. Phase synchronization in inhomogeneous globally coupled map lattices

    International Nuclear Information System (INIS)

    Ho Mingchung; Hung Yaochen; Jiang, I-M.

    2004-01-01

    The study of inhomogeneous-coupled chaotic systems has attracted a lot of attention recently. With simple definition of phase, we present the phase-locking behavior in ensembles of globally coupled non-identical maps. The inhomogeneous globally coupled maps consist of logistic map and tent map simultaneously. Average phase synchronization ratios, which are used to characterize the phase coherent phenomena, depend on different coupling coefficients and chaotic parameters. By using interdependence, the relationship between a single unit and the mean field is illustrated. Moreover, we take the effect of external noise and parameter mismatch into consideration and present the results by numerical simulation

  10. Cancerous tissue mapping from random lasing emission spectra

    International Nuclear Information System (INIS)

    Polson, R C; Vardeny, Z V

    2010-01-01

    Random lasing emission spectra have been collected from both healthy and cancerous tissues. The two types of tissue with optical gain have different light scattering properties as obtained from an average power Fourier transform of their random lasing emission spectra. The difference in the power Fourier transform leads to a contrast between cancerous and benign tissues, which is utilized for tissue mapping of healthy and cancerous regions of patients

  11. Entropic Phase Maps in Discrete Quantum Gravity

    Directory of Open Access Journals (Sweden)

    Benjamin F. Dribus

    2017-06-01

    Full Text Available Path summation offers a flexible general approach to quantum theory, including quantum gravity. In the latter setting, summation is performed over a space of evolutionary pathways in a history configuration space. Discrete causal histories called acyclic directed sets offer certain advantages over similar models appearing in the literature, such as causal sets. Path summation defined in terms of these histories enables derivation of discrete Schrödinger-type equations describing quantum spacetime dynamics for any suitable choice of algebraic quantities associated with each evolutionary pathway. These quantities, called phases, collectively define a phase map from the space of evolutionary pathways to a target object, such as the unit circle S 1 ⊂ C , or an analogue such as S 3 or S 7 . This paper explores the problem of identifying suitable phase maps for discrete quantum gravity, focusing on a class of S 1 -valued maps defined in terms of “structural increments” of histories, called terminal states. Invariants such as state automorphism groups determine multiplicities of states, and induce families of natural entropy functions. A phase map defined in terms of such a function is called an entropic phase map. The associated dynamical law may be viewed as an abstract combination of Schrödinger’s equation and the second law of thermodynamics.

  12. Creating and validating cis-regulatory maps of tissue-specific gene expression regulation

    Science.gov (United States)

    O'Connor, Timothy R.; Bailey, Timothy L.

    2014-01-01

    Predicting which genomic regions control the transcription of a given gene is a challenge. We present a novel computational approach for creating and validating maps that associate genomic regions (cis-regulatory modules–CRMs) with genes. The method infers regulatory relationships that explain gene expression observed in a test tissue using widely available genomic data for ‘other’ tissues. To predict the regulatory targets of a CRM, we use cross-tissue correlation between histone modifications present at the CRM and expression at genes within 1 Mbp of it. To validate cis-regulatory maps, we show that they yield more accurate models of gene expression than carefully constructed control maps. These gene expression models predict observed gene expression from transcription factor binding in the CRMs linked to that gene. We show that our maps are able to identify long-range regulatory interactions and improve substantially over maps linking genes and CRMs based on either the control maps or a ‘nearest neighbor’ heuristic. Our results also show that it is essential to include CRMs predicted in multiple tissues during map-building, that H3K27ac is the most informative histone modification, and that CAGE is the most informative measure of gene expression for creating cis-regulatory maps. PMID:25200088

  13. Tissue refractometry using Hilbert phase microscopy.

    Science.gov (United States)

    Lue, Niyom; Bewersdorf, Joerg; Lessard, Mark D; Badizadegan, Kamran; Dasari, Ramachandra R; Feld, Michael S; Popescu, Gabriel

    2007-12-15

    We present, for the first time to our knowledge, quantitative phase images associated with unstained 5 mum thick tissue slices of mouse brain, spleen, and liver. The refractive properties of the tissue are retrieved in terms of the average refractive index and its spatial variation. We find that the average refractive index varies significantly with tissue type, such that the brain is characterized by the lowest value and the liver by the highest. The spatial power spectra of the phase images reveal power law behavior with different exponents for each tissue type. This approach opens a new possibility for stain-free characterization of tissues, where the diagnostic power is provided by the intrinsic refractive properties of the biological structure. We present results obtained for liver tissue affected by a lysosomal storage disease and show that our technique can quantify structural changes during this disease development.

  14. Left ventricular regional myocardial motion and twist function in repaired tetralogy of Fallot evaluated by magnetic resonance tissue phase mapping

    International Nuclear Information System (INIS)

    Chang, Meng-Chu; Peng, Hsu-Hsia; Wu, Ming-Ting; Weng, Ken-Pen; Su, Mao-Yuan; Menza, Marius; Huang, Hung-Chieh

    2018-01-01

    We aimed to characterise regional myocardial motion and twist function in the left ventricles (LV) in patients with repaired tetralogy of Fallot (rTOF) and preserved LV global function. We recruited 47 rTOF patients and 38 age-matched normal volunteers. Tissue phase mapping (TPM) was performed for evaluating the LV myocardial velocity in longitudinal, radial, and circumferential (Vz, Vr, and VOe) directions in basal, middle, and apical slices. The VOe peak-to-peak (PTP) during systolic phases, the rotation angle of each slice, and VOe inconsistency were computed for evaluating LV twist function and VOe dyssynchrony. As compared to the controls, the rTOF patients presented decreased RV ejection fraction (RVEF) (p = 0.002) and preserved global LV ejection fraction (LVEF). They also demonstrated decreased systolic and diastolic Vz in several LV segments and higher diastolic Vr in the septum (all p < 0.05). A lower VOe PTP, higher VOe inconsistency, and reduced peak net rotation angle (all p < 0.05) were observed. The aforementioned indices demonstrated an altered LV twist function in rTOF patients in an early disease stage. MR TPM could provide information about early abnormalities of LV regional motion and twist function in rTOF patients with preserved LV global function. (orig.)

  15. Left ventricular regional myocardial motion and twist function in repaired tetralogy of Fallot evaluated by magnetic resonance tissue phase mapping

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Meng-Chu; Peng, Hsu-Hsia [National Tsing Hua University, Department of Biomedical Engineering and Environmental Sciences, Hsinchu (China); Wu, Ming-Ting [Kaohsiung Veterans General Hospital, Department of Radiology, Kaohsiung (China); National Yang-Ming University, Faculty of Medicine, Taipei (China); Weng, Ken-Pen [National Yang-Ming University, Faculty of Medicine, Taipei (China); Kaohsiung Veterans General Hospital, Department of Pediatrics, Kaohsiung (China); Shu-Zen Junior College of Medicine and Management, Department of Physical Therapy, Kaohsiung (China); Su, Mao-Yuan [National Taiwan University Hospital, Department of Medical Imaging, Taipei (China); Menza, Marius [Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Department of Radiology, Medical Physics, Freiburg (Germany); Huang, Hung-Chieh [Kaohsiung Veterans General Hospital, Department of Radiology, Kaohsiung (China)

    2018-01-15

    We aimed to characterise regional myocardial motion and twist function in the left ventricles (LV) in patients with repaired tetralogy of Fallot (rTOF) and preserved LV global function. We recruited 47 rTOF patients and 38 age-matched normal volunteers. Tissue phase mapping (TPM) was performed for evaluating the LV myocardial velocity in longitudinal, radial, and circumferential (Vz, Vr, and VOe) directions in basal, middle, and apical slices. The VOe peak-to-peak (PTP) during systolic phases, the rotation angle of each slice, and VOe inconsistency were computed for evaluating LV twist function and VOe dyssynchrony. As compared to the controls, the rTOF patients presented decreased RV ejection fraction (RVEF) (p = 0.002) and preserved global LV ejection fraction (LVEF). They also demonstrated decreased systolic and diastolic Vz in several LV segments and higher diastolic Vr in the septum (all p < 0.05). A lower VOe PTP, higher VOe inconsistency, and reduced peak net rotation angle (all p < 0.05) were observed. The aforementioned indices demonstrated an altered LV twist function in rTOF patients in an early disease stage. MR TPM could provide information about early abnormalities of LV regional motion and twist function in rTOF patients with preserved LV global function. (orig.)

  16. Expression cartography of human tissues using self organizing maps

    Directory of Open Access Journals (Sweden)

    Löffler Markus

    2011-07-01

    Full Text Available Abstract Background Parallel high-throughput microarray and sequencing experiments produce vast quantities of multidimensional data which must be arranged and analyzed in a concerted way. One approach to addressing this challenge is the machine learning technique known as self organizing maps (SOMs. SOMs enable a parallel sample- and gene-centered view of genomic data combined with strong visualization and second-level analysis capabilities. The paper aims at bridging the gap between the potency of SOM-machine learning to reduce dimension of high-dimensional data on one hand and practical applications with special emphasis on gene expression analysis on the other hand. Results The method was applied to generate a SOM characterizing the whole genome expression profiles of 67 healthy human tissues selected from ten tissue categories (adipose, endocrine, homeostasis, digestion, exocrine, epithelium, sexual reproduction, muscle, immune system and nervous tissues. SOM mapping reduces the dimension of expression data from ten of thousands of genes to a few thousand metagenes, each representing a minicluster of co-regulated single genes. Tissue-specific and common properties shared between groups of tissues emerge as a handful of localized spots in the tissue maps collecting groups of co-regulated and co-expressed metagenes. The functional context of the spots was discovered using overrepresentation analysis with respect to pre-defined gene sets of known functional impact. We found that tissue related spots typically contain enriched populations of genes related to specific molecular processes in the respective tissue. Analysis techniques normally used at the gene-level such as two-way hierarchical clustering are better represented and provide better signal-to-noise ratios if applied to the metagenes. Metagene-based clustering analyses aggregate the tissues broadly into three clusters containing nervous, immune system and the remaining tissues

  17. Asymptotically stable phase synchronization revealed by autoregressive circle maps

    Science.gov (United States)

    Drepper, F. R.

    2000-11-01

    A specially designed of nonlinear time series analysis is introduced based on phases, which are defined as polar angles in spaces spanned by a finite number of delayed coordinates. A canonical choice of the polar axis and a related implicit estimation scheme for the potentially underlying autoregressive circle map (next phase map) guarantee the invertibility of reconstructed phase space trajectories to the original coordinates. The resulting Fourier approximated, invertibility enforcing phase space map allows us to detect conditional asymptotic stability of coupled phases. This comparatively general synchronization criterion unites two existing generalizations of the old concept and can successfully be applied, e.g., to phases obtained from electrocardiogram and airflow recordings characterizing cardiorespiratory interaction.

  18. Phase analysis of circadian-related genes in two tissues

    Directory of Open Access Journals (Sweden)

    Li Leping

    2006-02-01

    Full Text Available Abstract Background Recent circadian clock studies using gene expression microarray in two different tissues of mouse have revealed not all circadian-related genes are synchronized in phase or peak expression times across tissues in vivo. Instead, some circadian-related genes may be delayed by 4–8 hrs in peak expression in one tissue relative to the other. These interesting biological observations prompt a statistical question regarding how to distinguish the synchronized genes from genes that are systematically lagged in phase/peak expression time across two tissues. Results We propose a set of techniques from circular statistics to analyze phase angles of circadian-related genes in two tissues. We first estimate the phases of a cycling gene separately in each tissue, which are then used to estimate the paired angular difference of the phase angles of the gene in the two tissues. These differences are modeled as a mixture of two von Mises distributions which enables us to cluster genes into two groups; one group having synchronized transcripts with the same phase in the two tissues, the other containing transcripts with a discrepancy in phase between the two tissues. For each cluster of genes we assess the association of phases across the tissue types using circular-circular regression. We also develop a bootstrap methodology based on a circular-circular regression model to evaluate the improvement in fit provided by allowing two components versus a one-component von-Mises model. Conclusion We applied our proposed methodologies to the circadian-related genes common to heart and liver tissues in Storch et al. 2, and found that an estimated 80% of circadian-related transcripts common to heart and liver tissues were synchronized in phase, and the other 20% of transcripts were lagged about 8 hours in liver relative to heart. The bootstrap p-value for being one cluster is 0.063, which suggests the possibility of two clusters. Our methodologies can

  19. OpenStreetMap Collaborative Prototype, Phase 1

    Science.gov (United States)

    Wolf, Eric B.; Matthews, Greg D.; McNinch, Kevin; Poore, Barbara S.

    2011-01-01

    Phase One of the OpenStreetMap Collaborative Prototype (OSMCP) attempts to determine if the open source software developed for the OpenStreetMap (OSM, http://www.openstreetmap.org) can be used for data contributions and improvements that meet or exceed the requirements for integration into The National Map (http://www.nationalmap.gov). OpenStreetMap Collaborative Prototype Phase One focused on road data aggregated at the state level by the Kansas Data Access and Support Center (DASC). Road data from the DASC were loaded into a system hosted by the U.S. Geological Survey (USGS) National Geospatial Technical Operations Center (NGTOC) in Rolla, Missouri. U.S. Geological Survey editing specifications were developed by NGTOC personnel (J. Walters and G. Matthews, USGS, unpub. report, 2010). Interstate and U.S. Highways in the dataset were edited to the specifications by NGTOC personnel while State roads were edited by DASC personnel. Resulting data were successfully improved to meet standards for The National Map once the system and specifications were in place. The OSM software proved effective in providing a usable platform for collaborative data editing

  20. Efficient characterization of phase space mapping in axially symmetric optical systems

    Science.gov (United States)

    Barbero, Sergio; Portilla, Javier

    2018-01-01

    Phase space mapping, typically between an object and image plane, characterizes an optical system within a geometrical optics framework. We propose a novel conceptual frame to characterize the phase mapping in axially symmetric optical systems for arbitrary object locations, not restricted to a specific object plane. The idea is based on decomposing the phase mapping into a set of bivariate equations corresponding to different values of the radial coordinate on a specific object surface (most likely the entrance pupil). These equations are then approximated through bivariate Chebyshev interpolation at Chebyshev nodes, which guarantees uniform convergence. Additionally, we propose the use of a new concept (effective object phase space), defined as the set of points of the phase space at the first optical element (typically the entrance pupil) that are effectively mapped onto the image surface. The effective object phase space provides, by means of an inclusion test, a way to avoid tracing rays that do not reach the image surface.

  1. Three-dimensional nanomechanical mapping of amorphous and crystalline phase transitions in phase-change materials.

    Science.gov (United States)

    Grishin, Ilja; Huey, Bryan D; Kolosov, Oleg V

    2013-11-13

    The nanostructure of micrometer-sized domains (bits) in phase-change materials (PCM) that undergo switching between amorphous and crystalline phases plays a key role in the performance of optical PCM-based memories. Here, we explore the dynamics of such phase transitions by mapping PCM nanostructures in three dimensions with nanoscale resolution by combining precision Ar ion beam cross-sectional polishing and nanomechanical ultrasonic force microscopy (UFM) mapping. Surface and bulk phase changes of laser written submicrometer to micrometer sized amorphous-to-crystalline (SET) and crystalline-to-amorphous (RESET) bits in chalcogenide Ge2Sb2Te5 PCM are observed with 10-20 nm lateral and 4 nm depth resolution. UFM mapping shows that the Young's moduli of crystalline SET bits exceed the moduli of amorphous areas by 11 ± 2%, with crystalline content extending from a few nanometers to 50 nm in depth depending on the energy of the switching pulses. The RESET bits written with 50 ps pulses reveal shallower depth penetration and show 30-50 nm lateral and few nanometer vertical wavelike topography that is anticorrelated with the elastic modulus distribution. Reverse switching of amorphous RESET bits results in the full recovery of subsurface nanomechanical properties accompanied with only partial topography recovery, resulting in surface corrugations attributed to quenching. This precision sectioning and nanomechanical mapping approach could be applicable to a wide range of amorphous, nanocrystalline, and glass-forming materials for 3D nanomechanical mapping of amorphous-crystalline transitions.

  2. Mapping absolute tissue endogenous fluorophore concentrations with chemometric wide-field fluorescence microscopy

    Science.gov (United States)

    Xu, Zhang; Reilley, Michael; Li, Run; Xu, Min

    2017-06-01

    We report chemometric wide-field fluorescence microscopy for imaging the spatial distribution and concentration of endogenous fluorophores in thin tissue sections. Nonnegative factorization aided by spatial diversity is used to learn both the spectral signature and the spatial distribution of endogenous fluorophores from microscopic fluorescence color images obtained under broadband excitation and detection. The absolute concentration map of individual fluorophores is derived by comparing the fluorescence from "pure" fluorophores under the identical imaging condition following the identification of the fluorescence species by its spectral signature. This method is then demonstrated by characterizing the concentration map of endogenous fluorophores (including tryptophan, elastin, nicotinamide adenine dinucleotide, and flavin adenine dinucleotide) for lung tissue specimens. The absolute concentrations of these fluorophores are all found to decrease significantly from normal, perilesional, to cancerous (squamous cell carcinoma) tissue. Discriminating tissue types using the absolute fluorophore concentration is found to be significantly more accurate than that achievable with the relative fluorescence strength. Quantification of fluorophores in terms of the absolute concentration map is also advantageous in eliminating the uncertainties due to system responses or measurement details, yielding more biologically relevant data, and simplifying the assessment of competing imaging approaches.

  3. Cardiac tissue slices: preparation, handling, and successful optical mapping.

    Science.gov (United States)

    Wang, Ken; Lee, Peter; Mirams, Gary R; Sarathchandra, Padmini; Borg, Thomas K; Gavaghan, David J; Kohl, Peter; Bollensdorff, Christian

    2015-05-01

    Cardiac tissue slices are becoming increasingly popular as a model system for cardiac electrophysiology and pharmacology research and development. Here, we describe in detail the preparation, handling, and optical mapping of transmembrane potential and intracellular free calcium concentration transients (CaT) in ventricular tissue slices from guinea pigs and rabbits. Slices cut in the epicardium-tangential plane contained well-aligned in-slice myocardial cell strands ("fibers") in subepicardial and midmyocardial sections. Cut with a high-precision slow-advancing microtome at a thickness of 350 to 400 μm, tissue slices preserved essential action potential (AP) properties of the precutting Langendorff-perfused heart. We identified the need for a postcutting recovery period of 36 min (guinea pig) and 63 min (rabbit) to reach 97.5% of final steady-state values for AP duration (APD) (identified by exponential fitting). There was no significant difference between the postcutting recovery dynamics in slices obtained using 2,3-butanedione 2-monoxime or blebistatin as electromechanical uncouplers during the cutting process. A rapid increase in APD, seen after cutting, was caused by exposure to ice-cold solution during the slicing procedure, not by tissue injury, differences in uncouplers, or pH-buffers (bicarbonate; HEPES). To characterize intrinsic patterns of CaT, AP, and conduction, a combination of multipoint and field stimulation should be used to avoid misinterpretation based on source-sink effects. In summary, we describe in detail the preparation, mapping, and data analysis approaches for reproducible cardiac tissue slice-based investigations into AP and CaT dynamics. Copyright © 2015 the American Physiological Society.

  4. Linear-fitting-based similarity coefficient map for tissue dissimilarity analysis in -w magnetic resonance imaging

    International Nuclear Information System (INIS)

    Yu Shao-De; Wu Shi-Bin; Xie Yao-Qin; Wang Hao-Yu; Wei Xin-Hua; Chen Xin; Pan Wan-Long; Hu Jiani

    2015-01-01

    Similarity coefficient mapping (SCM) aims to improve the morphological evaluation of weighted magnetic resonance imaging However, how to interpret the generated SCM map is still pending. Moreover, is it probable to extract tissue dissimilarity messages based on the theory behind SCM? The primary purpose of this paper is to address these two questions. First, the theory of SCM was interpreted from the perspective of linear fitting. Then, a term was embedded for tissue dissimilarity information. Finally, our method was validated with sixteen human brain image series from multi-echo . Generated maps were investigated from signal-to-noise ratio (SNR) and perceived visual quality, and then interpreted from intra- and inter-tissue intensity. Experimental results show that both perceptibility of anatomical structures and tissue contrast are improved. More importantly, tissue similarity or dissimilarity can be quantified and cross-validated from pixel intensity analysis. This method benefits image enhancement, tissue classification, malformation detection and morphological evaluation. (paper)

  5. Raman spectroscopic biochemical mapping of tissues

    Science.gov (United States)

    Stone, Nicholas; Hart Prieto, Maria C.; Kendall, Catherine A.; Shetty, Geeta; Barr, Hugh

    2006-02-01

    Advances in technologies have brought us closer to routine spectroscopic diagnosis of early malignant disease. However, there is still a poor understanding of the carcinogenesis process. For example it is not known whether many cancers follow a logical sequence from dysplasia, to carcinoma in situ, to invasion. Biochemical tissue changes, triggered by genetic mutations, precede morphological and structural changes. These can be probed using Raman or FTIR microspectroscopy and the spectra analysed for biochemical constituents. Local microscopic distribution of various constituents can then be visualised. Raman mapping has been performed on a number of tissues including oesophagus, breast, bladder and prostate. The biochemical constituents have been calculated at each point using basis spectra and least squares analysis. The residual of the least squares fit indicates any unfit spectral components. The biochemical distribution will be compared with the defined histopathological boundaries. The distribution of nucleic acids, glycogen, actin, collagen I, III, IV, lipids and others appear to follow expected patterns.

  6. Tomographic image reconstruction using x-ray phase information

    Science.gov (United States)

    Momose, Atsushi; Takeda, Tohoru; Itai, Yuji; Hirano, Keiichi

    1996-04-01

    We have been developing phase-contrast x-ray computed tomography (CT) to make possible the observation of biological soft tissues without contrast enhancement. Phase-contrast x-ray CT requires for its input data the x-ray phase-shift distributions or phase-mapping images caused by an object. These were measured with newly developed fringe-scanning x-ray interferometry. Phase-mapping images at different projection directions were obtained by rotating the object in an x-ray interferometer, and were processed with a standard CT algorithm. A phase-contrast x-ray CT image of a nonstained cancerous tissue was obtained using 17.7 keV synchrotron x rays with 12 micrometer voxel size, although the size of the observation area was at most 5 mm. The cancerous lesions were readily distinguishable from normal tissues. Moreover, fine structures corresponding to cancerous degeneration and fibrous tissues were clearly depicted. It is estimated that the present system is sensitive down to a density deviation of 4 mg/cm3.

  7. Phase congruency map driven brain tumour segmentation

    Science.gov (United States)

    Szilágyi, Tünde; Brady, Michael; Berényi, Ervin

    2015-03-01

    Computer Aided Diagnostic (CAD) systems are already of proven value in healthcare, especially for surgical planning, nevertheless much remains to be done. Gliomas are the most common brain tumours (70%) in adults, with a survival time of just 2-3 months if detected at WHO grades III or higher. Such tumours are extremely variable, necessitating multi-modal Magnetic Resonance Images (MRI). The use of Gadolinium-based contrast agents is only relevant at later stages of the disease where it highlights the enhancing rim of the tumour. Currently, there is no single accepted method that can be used as a reference. There are three main challenges with such images: to decide whether there is tumour present and is so localize it; to construct a mask that separates healthy and diseased tissue; and to differentiate between the tumour core and the surrounding oedema. This paper presents two contributions. First, we develop tumour seed selection based on multiscale multi-modal texture feature vectors. Second, we develop a method based on a local phase congruency based feature map to drive level-set segmentation. The segmentations achieved with our method are more accurate than previously presented methods, particularly for challenging low grade tumours.

  8. Mapping Isobaric Aging onto the Equilibrium Phase Diagram

    DEFF Research Database (Denmark)

    Niss, Kristine

    2017-01-01

    The linear volume relaxation and the nonlinear volume aging of a glass-forming liquid are measured, directly compared, and used to extract the out-of-equilibrium relaxation time. This opens a window to investigate how the relaxation time depends on temperature, structure, and volume in parts...... of phase space that are not accessed by the equilibrium liquid. It is found that the temperature dependence of relaxation time is non-Arrhenius even in the isostructural case—challenging the Adam-Gibbs entropy model. Based on the presented data and the idea that aging happens through quasiequilibrium...... states, we suggest a mapping of the out-of-equilibrium states during isobaric aging to the equilibrium phase diagram. This mapping implies the existence of isostructural lines in the equilibrium phase diagram. The relaxation time is found to depend on the bath temperature, density, and a just single...

  9. Mapping Isobaric Aging onto the Equilibrium Phase Diagram.

    Science.gov (United States)

    Niss, Kristine

    2017-09-15

    The linear volume relaxation and the nonlinear volume aging of a glass-forming liquid are measured, directly compared, and used to extract the out-of-equilibrium relaxation time. This opens a window to investigate how the relaxation time depends on temperature, structure, and volume in parts of phase space that are not accessed by the equilibrium liquid. It is found that the temperature dependence of relaxation time is non-Arrhenius even in the isostructural case-challenging the Adam-Gibbs entropy model. Based on the presented data and the idea that aging happens through quasiequilibrium states, we suggest a mapping of the out-of-equilibrium states during isobaric aging to the equilibrium phase diagram. This mapping implies the existence of isostructural lines in the equilibrium phase diagram. The relaxation time is found to depend on the bath temperature, density, and a just single structural parameter, referred to as an effective temperature.

  10. Phase-Contrast Hounsfield Units of Fixated and Non-Fixated Soft-Tissue Samples

    Science.gov (United States)

    Willner, Marian; Fior, Gabriel; Marschner, Mathias; Birnbacher, Lorenz; Schock, Jonathan; Braun, Christian; Fingerle, Alexander A.; Noël, Peter B.; Rummeny, Ernst J.; Pfeiffer, Franz; Herzen, Julia

    2015-01-01

    X-ray phase-contrast imaging is a novel technology that achieves high soft-tissue contrast. Although its clinical impact is still under investigation, the technique may potentially improve clinical diagnostics. In conventional attenuation-based X-ray computed tomography, radiological diagnostics are quantified by Hounsfield units. Corresponding Hounsfield units for phase-contrast imaging have been recently introduced, enabling a setup-independent comparison and standardized interpretation of imaging results. Thus far, the experimental values of few tissue types have been reported; these values have been determined from fixated tissue samples. This study presents phase-contrast Hounsfield units for various types of non-fixated human soft tissues. A large variety of tissue specimens ranging from adipose, muscle and connective tissues to liver, kidney and pancreas tissues were imaged by a grating interferometer with a rotating-anode X-ray tube and a photon-counting detector. Furthermore, we investigated the effects of formalin fixation on the quantitative phase-contrast imaging results. PMID:26322638

  11. Quantitative breast tissue characterization using grating-based x-ray phase-contrast imaging

    Science.gov (United States)

    Willner, M.; Herzen, J.; Grandl, S.; Auweter, S.; Mayr, D.; Hipp, A.; Chabior, M.; Sarapata, A.; Achterhold, K.; Zanette, I.; Weitkamp, T.; Sztrókay, A.; Hellerhoff, K.; Reiser, M.; Pfeiffer, F.

    2014-04-01

    X-ray phase-contrast imaging has received growing interest in recent years due to its high capability in visualizing soft tissue. Breast imaging became the focus of particular attention as it is considered the most promising candidate for a first clinical application of this contrast modality. In this study, we investigate quantitative breast tissue characterization using grating-based phase-contrast computed tomography (CT) at conventional polychromatic x-ray sources. Different breast specimens have been scanned at a laboratory phase-contrast imaging setup and were correlated to histopathology. Ascertained tumor types include phylloides tumor, fibroadenoma and infiltrating lobular carcinoma. Identified tissue types comprising adipose, fibroglandular and tumor tissue have been analyzed in terms of phase-contrast Hounsfield units and are compared to high-quality, high-resolution data obtained with monochromatic synchrotron radiation, as well as calculated values based on tabulated tissue properties. The results give a good impression of the method’s prospects and limitations for potential tumor detection and the associated demands on such a phase-contrast breast CT system. Furthermore, the evaluated quantitative tissue values serve as a reference for simulations and the design of dedicated phantoms for phase-contrast mammography.

  12. X-ray phase-contrast tomosynthesis for improved breast tissue discrimination

    International Nuclear Information System (INIS)

    Schleede, Simone; Bech, Martin; Grandl, Susanne; Sztrókay, Aniko; Herzen, Julia; Mayr, Doris; Stockmar, Marco; Potdevin, Guillaume

    2014-01-01

    Purpose: Attenuation-based tomosynthesis has proven to successfully resolve the glandular tissue overlap present in mammography. However, the ability of tomosynthesis to differentiate tumorous and glandular tissue remains limited, due to the small differences in X-ray attenuation in breast tissue. One possibility to overcome this limitation and to further increase the diagnostic value of tomosynthesis exams, is the application of recently developed grating-based phase-contrast methods, which provide complementary information on the phase shift and the local scattering power of the sample. In this study, we report on first phase-contrast breast tomosynthesis results of a mastectomy sample slice with an invasive ductal carcinoma. Material and methods: A slice of a mastectomy sample with histologically proven invasive ductal cancer was imaged at the synchrotron radiation source ESRF (Grenoble, France). We used a two-grating interferometer setup at the ninth fractional Talbot distance and with an X-ray energy of 23 keV. In grating interferometry absorption, differential phase, and scattering images are recorded simultaneously. The tomosynthesis scan comprises 61 projections. Multimodal tomosynthesis results were reconstructed using a standard filtered back-projection approach. Our findings are supported by a comparison of tomographic views to histopathology. Results: Phase-contrast tomosynthesis combines the advantage of improved soft-tissue discrimination in phase-contrast imaging with the ability of tomosynthesis to provide a third dimension so that improved feature visibility is not hampered by superposition artifacts. Our results indicate superior diagnostic value due to the depth resolution supplied in tomosynthesis imaging; a region of necrotic tissue that is obscured in a projection image can clearly be depicted in one single tomosynthesis slice. Compared to absorption tomosynthesis alone, soft tissue contrast is significantly enhanced in phase

  13. X-ray phase-contrast tomosynthesis for improved breast tissue discrimination.

    Science.gov (United States)

    Schleede, Simone; Bech, Martin; Grandl, Susanne; Sztrókay, Aniko; Herzen, Julia; Mayr, Doris; Stockmar, Marco; Potdevin, Guillaume; Zanette, Irene; Rack, Alexander; Weitkamp, Timm; Pfeiffer, Franz

    2014-03-01

    Attenuation-based tomosynthesis has proven to successfully resolve the glandular tissue overlap present in mammography. However, the ability of tomosynthesis to differentiate tumorous and glandular tissue remains limited, due to the small differences in X-ray attenuation in breast tissue. One possibility to overcome this limitation and to further increase the diagnostic value of tomosynthesis exams, is the application of recently developed grating-based phase-contrast methods, which provide complementary information on the phase shift and the local scattering power of the sample. In this study, we report on first phase-contrast breast tomosynthesis results of a mastectomy sample slice with an invasive ductal carcinoma. A slice of a mastectomy sample with histologically proven invasive ductal cancer was imaged at the synchrotron radiation source ESRF (Grenoble, France). We used a two-grating interferometer setup at the ninth fractional Talbot distance and with an X-ray energy of 23 keV. In grating interferometry absorption, differential phase, and scattering images are recorded simultaneously. The tomosynthesis scan comprises 61 projections. Multimodal tomosynthesis results were reconstructed using a standard filtered back-projection approach. Our findings are supported by a comparison of tomographic views to histopathology. Phase-contrast tomosynthesis combines the advantage of improved soft-tissue discrimination in phase-contrast imaging with the ability of tomosynthesis to provide a third dimension so that improved feature visibility is not hampered by superposition artifacts. Our results indicate superior diagnostic value due to the depth resolution supplied in tomosynthesis imaging; a region of necrotic tissue that is obscured in a projection image can clearly be depicted in one single tomosynthesis slice. Compared to absorption tomosynthesis alone, soft tissue contrast is significantly enhanced in phase-contrast tomosynthesis views, where fibrous structures

  14. The average baboon brain: MRI templates and tissue probability maps from 89 individuals.

    Science.gov (United States)

    Love, Scott A; Marie, Damien; Roth, Muriel; Lacoste, Romain; Nazarian, Bruno; Bertello, Alice; Coulon, Olivier; Anton, Jean-Luc; Meguerditchian, Adrien

    2016-05-15

    The baboon (Papio) brain is a remarkable model for investigating the brain. The current work aimed at creating a population-average baboon (Papio anubis) brain template and its left/right hemisphere symmetric version from a large sample of T1-weighted magnetic resonance images collected from 89 individuals. Averaging the prior probability maps output during the segmentation of each individual also produced the first baboon brain tissue probability maps for gray matter, white matter and cerebrospinal fluid. The templates and the tissue probability maps were created using state-of-the-art, freely available software tools and are being made freely and publicly available: http://www.nitrc.org/projects/haiko89/ or http://lpc.univ-amu.fr/spip.php?article589. It is hoped that these images will aid neuroimaging research of the baboon by, for example, providing a modern, high quality normalization target and accompanying standardized coordinate system as well as probabilistic priors that can be used during tissue segmentation. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Quantitative susceptibility mapping (QSM): Decoding MRI data for a tissue magnetic biomarker

    Science.gov (United States)

    Wang, Yi; Liu, Tian

    2015-01-01

    In MRI, the main magnetic field polarizes the electron cloud of a molecule, generating a chemical shift for observer protons within the molecule and a magnetic susceptibility inhomogeneity field for observer protons outside the molecule. The number of water protons surrounding a molecule for detecting its magnetic susceptibility is vastly greater than the number of protons within the molecule for detecting its chemical shift. However, the study of tissue magnetic susceptibility has been hindered by poor molecular specificities of hitherto used methods based on MRI signal phase and T2* contrast, which depend convolutedly on surrounding susceptibility sources. Deconvolution of the MRI signal phase can determine tissue susceptibility but is challenged by the lack of MRI signal in the background and by the zeroes in the dipole kernel. Recently, physically meaningful regularizations, including the Bayesian approach, have been developed to enable accurate quantitative susceptibility mapping (QSM) for studying iron distribution, metabolic oxygen consumption, blood degradation, calcification, demyelination, and other pathophysiological susceptibility changes, as well as contrast agent biodistribution in MRI. This paper attempts to summarize the basic physical concepts and essential algorithmic steps in QSM, to describe clinical and technical issues under active development, and to provide references, codes, and testing data for readers interested in QSM. Magn Reson Med 73:82–101, 2015. © 2014 The Authors. Magnetic Resonance in Medicine Published by Wiley Periodicals, Inc. on behalf of International Society of Medicine in Resonance. This is an open access article under the terms of the Creative commons Attribution License, which permits use, distribution, and reproduction in any medium, provided the original work is properly cited. PMID:25044035

  16. Outcome Mapping Virtual Learning Community - Phase II | IDRC ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    The first phase of the project (103520) focused on developing the Outcome ... as distance learning) and strategically communicating Outcome Mapping to key ... an organization based in India with South Asian reach, to facilitate exchange ...

  17. MAP3K8 (TPL2/COT affects obesity-induced adipose tissue inflammation without systemic effects in humans and in mice.

    Directory of Open Access Journals (Sweden)

    Dov B Ballak

    Full Text Available Chronic low-grade inflammation in adipose tissue often accompanies obesity, leading to insulin resistance and increasing the risk for metabolic diseases. MAP3K8 (TPL2/COT is an important signal transductor and activator of pro-inflammatory pathways that has been linked to obesity-induced adipose tissue inflammation. We used human adipose tissue biopsies to study the relationship of MAP3K8 expression with markers of obesity and expression of pro-inflammatory cytokines (IL-1β, IL-6 and IL-8. Moreover, we evaluated obesity-induced adipose tissue inflammation and insulin resistance in mice lacking MAP3K8 and WT mice on a high-fat diet (HFD for 16 weeks. Individuals with a BMI >30 displayed a higher mRNA expression of MAP3K8 in adipose tissue compared to individuals with a normal BMI. Additionally, high mRNA expression levels of IL-1β, IL-6 and IL-8, but not TNF -α, in human adipose tissue were associated with higher expression of MAP3K8. Moreover, high plasma SAA and CRP did not associate with increased MAP3K8 expression in adipose tissue. Similarly, no association was found for MAP3K8 expression with plasma insulin or glucose levels. Mice lacking MAP3K8 had similar bodyweight gain as WT mice, yet displayed lower mRNA expression levels of IL-1β, IL-6 and CXCL1 in adipose tissue in response to the HFD as compared to WT animals. However, MAP3K8 deficient mice were not protected against HFD-induced adipose tissue macrophage infiltration or the development of insulin resistance. Together, the data in both human and mouse show that MAP3K8 is involved in local adipose tissue inflammation, specifically for IL-1β and its responsive cytokines IL-6 and IL-8, but does not seem to have systemic effects on insulin resistance.

  18. Beam Position and Phase Monitor - Wire Mapping System

    International Nuclear Information System (INIS)

    Watkins, Heath A.; Shurter, Robert B.; Gilpatrick, John D.; Kutac, Vincent G.; Martinez, Derwin

    2012-01-01

    The Los Alamos Neutron Science Center (LANSCE) deploys many cylindrical beam position and phase monitors (BPPM) throughout the linac to measure the beam central position, phase and bunched-beam current. Each monitor is calibrated and qualified prior to installation to insure it meets LANSCE requirements. The BPPM wire mapping system is used to map the BPPM electrode offset, sensitivity and higher order coefficients. This system uses a three-axis motion table to position the wire antenna structure within the cavity, simulating the beam excitation of a BPPM at a fundamental frequency of 201.25 MHz. RF signal strength is measured and recorded for the four electrodes as the antenna position is updated. An effort is underway to extend the systems service to the LANSCE facility by replacing obsolete electronic hardware and taking advantage of software enhancements. This paper describes the upgraded wire positioning system's new hardware and software capabilities including its revised antenna structure, motion control interface, RF measurement equipment and Labview software upgrades. The main purpose of the wire mapping system at LANSCE is to characterize the amplitude response versus beam central position of BPPMs before they are installed in the beam line. The wire mapping system is able to simulate a beam using a thin wire and measure the signal response as the wire position is varied within the BPPM aperture.

  19. Enhancement of bone shadow region using local phase-based ultrasound transmission maps.

    Science.gov (United States)

    Hacihaliloglu, Ilker

    2017-06-01

    Ultrasound is increasingly being employed in different orthopedic procedures as an imaging modality for real-time guidance. Nevertheless, low signal-to-noise-ratio and different imaging artifacts continue to hamper the success of ultrasound-based procedures. Bone shadow region is an important feature indicating the presence of bone/tissue interface in the acquired ultrasound data. Enhancement and automatic detection of this region could improve the sensitivity of ultrasound for imaging bone and result in improved guidance for various orthopedic procedures. In this work, a method is introduced for the enhancement of bone shadow regions from B-mode ultrasound data. The method is based on the combination of three different image phase features: local phase tensor, local weighted mean phase angle, and local phase energy. The combined local phase image features are used as an input to an [Formula: see text] norm-based contextual regularization method which emphasizes uncertainty in the shadow regions. The enhanced bone shadow images are automatically segmented and compared against expert segmentation. Qualitative and quantitative validation was performed on 100 in vivo US scans obtained from five subjects by scanning femur and vertebrae bones. Validation against expert segmentation achieved a mean dice similarity coefficient of 0.88. The encouraging results obtained in this initial study suggest that the proposed method is promising enough for further evaluation. The calculated bone shadow maps could be incorporated into different ultrasound bone segmentation and registration approaches as an additional feature.

  20. METABOLIC MAPPING BY ENZYME HISTOCHEMISTRY IN LIVING ANIMALS, TISSUES AND CELLS

    NARCIS (Netherlands)

    van Noorden, C. J. F.

    2009-01-01

    Imaging of reporter molecules such as fluorescent proteins in intact animals, tissue and cells has become an indispensable tool in cell biology Imaging activity of enzymes, which is called metabolic mapping, provides information on subcellular localisation in combination with function of the enzymes

  1. Rapid Construction of Fe-Co-Ni Composition-Phase Map by Combinatorial Materials Chip Approach.

    Science.gov (United States)

    Xing, Hui; Zhao, Bingbing; Wang, Yujie; Zhang, Xiaoyi; Ren, Yang; Yan, Ningning; Gao, Tieren; Li, Jindong; Zhang, Lanting; Wang, Hong

    2018-03-12

    One hundred nanometer thick Fe-Co-Ni material chips were prepared and isothermally annealed at 500, 600, and 700 °C, respectively. Pixel-by-pixel composition and structural mapping was performed by microbeam X-ray at synchrotron light source. Diffraction images were recorded at a rate of 1 pattern/s. The XRD patterns were automatically processed, phase-identified, and categorized by hierarchical clustering algorithm to construct the composition-phase map. The resulting maps are consistent with corresponding isothermal sections reported in the ASM Alloy Phase Diagram Database, verifying the effectiveness of the present approach in phase diagram construction.

  2. Ray calibration and phase mapping for structured-light-field 3D reconstruction.

    Science.gov (United States)

    Cai, Zewei; Liu, Xiaoli; Peng, Xiang; Gao, Bruce Z

    2018-03-19

    In previous work, we presented a structured light field (SLF) method combining light field imaging with structured illumination to perform multi-view depth measurement. However, the previous work just accomplishes depth rather than 3D reconstruction. In this paper, we propose a novel active method involving ray calibration and phase mapping, to achieve SLF 3D reconstruction. We performed the ray calibration for the first time to determine each light field ray with metric spatio-angular parameters, making the SLF realize multi-view 3D reconstruction. Based on the ray parametric equation, we further derived the phase mapping in the SLF that spatial coordinates can be directly mapped from phase. A flexible calibration strategy was correspondently designed to determine mapping coefficients for each light field ray, achieving high-efficiency SLF 3D reconstruction. Experimental results demonstrated that the proposed method was suitable for high-efficiency multi-view 3D reconstruction in the SLF.

  3. Direct dose mapping versus energy/mass transfer mapping for 4D dose accumulation: fundamental differences and dosimetric consequences.

    Science.gov (United States)

    Li, Haisen S; Zhong, Hualiang; Kim, Jinkoo; Glide-Hurst, Carri; Gulam, Misbah; Nurushev, Teamour S; Chetty, Indrin J

    2014-01-06

    The direct dose mapping (DDM) and energy/mass transfer (EMT) mapping are two essential algorithms for accumulating the dose from different anatomic phases to the reference phase when there is organ motion or tumor/tissue deformation during the delivery of radiation therapy. DDM is based on interpolation of the dose values from one dose grid to another and thus lacks rigor in defining the dose when there are multiple dose values mapped to one dose voxel in the reference phase due to tissue/tumor deformation. On the other hand, EMT counts the total energy and mass transferred to each voxel in the reference phase and calculates the dose by dividing the energy by mass. Therefore it is based on fundamentally sound physics principles. In this study, we implemented the two algorithms and integrated them within the Eclipse treatment planning system. We then compared the clinical dosimetric difference between the two algorithms for ten lung cancer patients receiving stereotactic radiosurgery treatment, by accumulating the delivered dose to the end-of-exhale (EE) phase. Specifically, the respiratory period was divided into ten phases and the dose to each phase was calculated and mapped to the EE phase and then accumulated. The displacement vector field generated by Demons-based registration of the source and reference images was used to transfer the dose and energy. The DDM and EMT algorithms produced noticeably different cumulative dose in the regions with sharp mass density variations and/or high dose gradients. For the planning target volume (PTV) and internal target volume (ITV) minimum dose, the difference was up to 11% and 4% respectively. This suggests that DDM might not be adequate for obtaining an accurate dose distribution of the cumulative plan, instead, EMT should be considered.

  4. Investigating mechanically induced phase response of the tissue by using high-speed phase-resolved optical coherence tomography (Conference Presentation)

    Science.gov (United States)

    Ling, Yuye; Hendon, Christine P.

    2017-02-01

    Phase-resolved optical coherence tomography (OCT), a functional extension of OCT, provides depth-resolved phase information with extra contrast. In cardiology, changes in the mechanical properties have been associated with tissue remodeling and disease progression. Here we present the capability of profiling structural deformation of the sample in vivo by using a highly stable swept source OCT system The system, operating at 1300 nm, has an A-line acquisition rate of 200 kHz. We measured the phase noise floor to be 6.5 pm±3.2 pm by placing a cover slip in the sample arm, while blocking the reference arm. We then conducted a vibrational frequency test by measuring the phase response from a polymer membrane stimulated by a pure tone acoustic wave from 10 kHz to 80 kHz. The measured frequency response agreed with the known stimulation frequency with an error < 0.005%. We further measured the phase response of 7 fresh swine hearts obtained from Green Village Packing Company through a mechanical stretching test, within 24 hours of sacrifice. The heart tissue was cut into a 1 mm slices and fixed on two motorized stages. We acquired 100,000 consecutive M-scans, while the sample is stretched at a constant velocity of 10 um/s. The depth-resolved phase image presents linear phase response over time at each depth, but the slope varies among tissue types. Our future work includes refining our experiment protocol to quantitatively measured the elastic modulus of the tissue in vivo and building a tissue classifier based on depth-resolved phase information.

  5. Towards optical spectroscopic anatomical mapping (OSAM) for lesion validation in cardiac tissue (Conference Presentation)

    Science.gov (United States)

    Singh-Moon, Rajinder P.; Zaryab, Mohammad; Hendon, Christine P.

    2017-02-01

    Electroanatomical mapping (EAM) is an invaluable tool for guiding cardiac radiofrequency ablation (RFA) therapy. The principle roles of EAM is the identification of candidate ablation sites by detecting regions of abnormal electrogram activity and lesion validation subsequent to RF energy delivery. However, incomplete lesions may present interim electrical inactivity similar to effective treatment in the acute setting, despite efforts to reveal them with pacing or drugs, such as adenosine. Studies report that the misidentification and recovery of such lesions is a leading cause of arrhythmia recurrence and repeat procedures. In previous work, we demonstrated spectroscopic characterization of cardiac tissues using a fiber optic-integrated RF ablation catheter. In this work, we introduce OSAM (optical spectroscopic anatomical mapping), the application of this spectroscopic technique to obtain 2-dimensional biodistribution maps. We demonstrate its diagnostic potential as an auxiliary method for lesion validation in treated swine preparations. Endocardial lesion sets were created on fresh swine cardiac samples using a commercial RFA system. An optically-integrated catheter console fabricated in-house was used for measurement of tissue optical spectra between 600-1000nm. Three dimensional, Spatio-spectral datasets were generated by raster scanning of the optical catheter across the treated sample surface in the presence of whole blood. Tissue optical parameters were recovered at each spatial position using an inverse Monte Carlo method. OSAM biodistribution maps showed stark correspondence with gross examination of tetrazolium chloride stained tissue specimens. Specifically, we demonstrate the ability of OSAM to readily distinguish between shallow and deeper lesions, a limitation faced by current EAM techniques. These results showcase the OSAMs potential for lesion validation strategies for the treatment of cardiac arrhythmias.

  6. Spatial cluster analysis of nanoscopically mapped serotonin receptors for classification of fixed brain tissue

    Science.gov (United States)

    Sams, Michael; Silye, Rene; Göhring, Janett; Muresan, Leila; Schilcher, Kurt; Jacak, Jaroslaw

    2014-01-01

    We present a cluster spatial analysis method using nanoscopic dSTORM images to determine changes in protein cluster distributions within brain tissue. Such methods are suitable to investigate human brain tissue and will help to achieve a deeper understanding of brain disease along with aiding drug development. Human brain tissue samples are usually treated postmortem via standard fixation protocols, which are established in clinical laboratories. Therefore, our localization microscopy-based method was adapted to characterize protein density and protein cluster localization in samples fixed using different protocols followed by common fluorescent immunohistochemistry techniques. The localization microscopy allows nanoscopic mapping of serotonin 5-HT1A receptor groups within a two-dimensional image of a brain tissue slice. These nanoscopically mapped proteins can be confined to clusters by applying the proposed statistical spatial analysis. Selected features of such clusters were subsequently used to characterize and classify the tissue. Samples were obtained from different types of patients, fixed with different preparation methods, and finally stored in a human tissue bank. To verify the proposed method, samples of a cryopreserved healthy brain have been compared with epitope-retrieved and paraffin-fixed tissues. Furthermore, samples of healthy brain tissues were compared with data obtained from patients suffering from mental illnesses (e.g., major depressive disorder). Our work demonstrates the applicability of localization microscopy and image analysis methods for comparison and classification of human brain tissues at a nanoscopic level. Furthermore, the presented workflow marks a unique technological advance in the characterization of protein distributions in brain tissue sections.

  7. High-spatial-resolution mapping of the oxygen concentration in cortical tissue (Conference Presentation)

    Science.gov (United States)

    Jaswal, Rajeshwer S.; Yaseen, Mohammad A.; Fu, Buyin; Boas, David A.; Sakadžic, Sava

    2016-03-01

    Due to a lack of imaging tools for high-resolution imaging of cortical tissue oxygenation, the detailed maps of the oxygen partial pressure (PO2) around arterioles, venules, and capillaries remain largely unknown. Therefore, we have limited knowledge about the mechanisms that secure sufficient oxygen delivery in microvascular domains during brain activation, and provide some metabolic reserve capacity in diseases that affect either microvascular networks or the regulation of cerebral blood flow (CBF). To address this challenge, we applied a Two-Photon PO2 Microscopy to map PO2 at different depths in mice cortices. Measurements were performed through the cranial window in the anesthetized healthy mice as well as in the mouse models of microvascular dysfunctions. In addition, microvascular morphology was recorded by the two-photon microscopy at the end of each experiment and subsequently segmented. Co-registration of the PO2 measurements and exact microvascular morphology enabled quantification of the tissue PO2 dependence on distance from the arterioles, capillaries, and venules at various depths. Our measurements reveal significant spatial heterogeneity of the cortical tissue PO2 distribution that is dominated by the high oxygenation in periarteriolar spaces. In cases of impaired oxygen delivery due to microvascular dysfunction, significant reduction in tissue oxygenation away from the arterioles was observed. These tissue domains may be the initial sites of cortical injury that can further exacerbate the progression of the disease.

  8. Computational cell quantification in the human brain tissues based on hard x-ray phase-contrast tomograms

    Science.gov (United States)

    Hieber, Simone E.; Bikis, Christos; Khimchenko, Anna; Schulz, Georg; Deyhle, Hans; Thalmann, Peter; Chicherova, Natalia; Rack, Alexander; Zdora, Marie-Christine; Zanette, Irene; Schweighauser, Gabriel; Hench, Jürgen; Müller, Bert

    2016-10-01

    Cell visualization and counting plays a crucial role in biological and medical research including the study of neurodegenerative diseases. The neuronal cell loss is typically determined to measure the extent of the disease. Its characterization is challenging because the cell density and size already differs by more than three orders of magnitude in a healthy cerebellum. Cell visualization is commonly performed by histology and fluorescence microscopy. These techniques are limited to resolve complex microstructures in the third dimension. Phase- contrast tomography has been proven to provide sufficient contrast in the three-dimensional imaging of soft tissue down to the cell level and, therefore, offers the basis for the three-dimensional segmentation. Within this context, a human cerebellum sample was embedded in paraffin and measured in local phase-contrast mode at the beamline ID19 (ESRF, Grenoble, France) and the Diamond Manchester Imaging Branchline I13-2 (Diamond Light Source, Didcot, UK). After the application of Frangi-based filtering the data showed sufficient contrast to automatically identify the Purkinje cells and to quantify their density to 177 cells per mm3 within the volume of interest. Moreover, brain layers were segmented in a region of interest based on edge detection. Subsequently performed histological analysis validated the presence of the cells, which required a mapping from the two- dimensional histological slices to the three-dimensional tomogram. The methodology can also be applied to further tissue types and shows potential for the computational tissue analysis in health and disease.

  9. A regularized, model-based approach to phase-based conductivity mapping using MRI.

    Science.gov (United States)

    Ropella, Kathleen M; Noll, Douglas C

    2017-11-01

    To develop a novel regularized, model-based approach to phase-based conductivity mapping that uses structural information to improve the accuracy of conductivity maps. The inverse of the three-dimensional Laplacian operator is used to model the relationship between measured phase maps and the object conductivity in a penalized weighted least-squares optimization problem. Spatial masks based on structural information are incorporated into the problem to preserve data near boundaries. The proposed Inverse Laplacian method was compared against a restricted Gaussian filter in simulation, phantom, and human experiments. The Inverse Laplacian method resulted in lower reconstruction bias and error due to noise in simulations than the Gaussian filter. The Inverse Laplacian method also produced conductivity maps closer to the measured values in a phantom and with reduced noise in the human brain, as compared to the Gaussian filter. The Inverse Laplacian method calculates conductivity maps with less noise and more accurate values near boundaries. Improving the accuracy of conductivity maps is integral for advancing the applications of conductivity mapping. Magn Reson Med 78:2011-2021, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  10. Phase mapping of iron-based rapidly quenched alloys using precession electron diffraction

    International Nuclear Information System (INIS)

    Svec, P.; Janotova, I.; Hosko, J.; Matko, I.; Janickovic, D.; Svec, P. Sr.; Kepaptsoglou, D. M.

    2013-01-01

    The present contribution is focused on application of PED and phase/orientation mapping of nanocrystals of bcc-Fe formed during the first crystallization stage of amorphous Fe-Co-Si-B ribbon. Using precession electron diffraction and phase/orientation mapping the formation of primary crystalline phase, bcc-Fe, from amorphous Fe-Co-Si-B has been analyzed. Important information about mutual orientation of the phase in individual submicron grains as well as against the sample surface has been obtained. This information contributes to the understanding of micromechanisms controlling crystallization from amorphous rapidly quenched structure and of the structure of the original amorphous state. The presented technique due to its high spatial resolution, speed and information content provided complements well classical techniques, especially in nanocrystalline materials. (authors)

  11. Phase-mapping technique for the evaluation of aortic valve stenosis by MR

    International Nuclear Information System (INIS)

    Engels, G.; Mueller, E.; Reynen, K.; Wilke, N.; Bachmann, K.

    1992-01-01

    New MR-techniques for quantitative blood flow registration such as phase-mapping (a two-dimensional space-resolved technique with a time-averaged measurement of blood flow) or RACE (real-time acquisition and evaluation of blood flow in one-dimensional space projection) are available for the diagnosis of valvular heart disease. Initial results of grading aortic valve stenosis by these methods are shown in comparison to continuous wave Ultrasound-Doppler. Two groups of 15 patients were examined by RACE or phase-mapping, 12 respectively 8 of whom suffered from an aortic valve stenosis. The shape of blood flow profiles as well as grading of aortic valve stenosis show high concordance when comparing the results of MR and Doppler technique. Good reliability and practicability of the demonstrated MR-method are shown. With respect to the results of RACE and phase-mapping the development of an alternative and competing MR-method for the evaluation of valvular heart disease and shunt diagnostics seems possible. (orig.)

  12. Phase-mapping technique for the evaluation of aortic valve stenosis by MR

    Energy Technology Data Exchange (ETDEWEB)

    Engels, G. [Medizinische Klinik 2, Univ. of Erlangen (Germany); Mueller, E. [Siemens Medical Engineering Group, Erlangen (Germany); Reynen, K. [Medizinische Klinik 2, Univ. of Erlangen (Germany); Wilke, N. [Siemens Medical Engineering Group, Erlangen (Germany); Bachmann, K. [Medizinische Klinik 2, Univ. of Erlangen (Germany)

    1992-08-01

    New MR-techniques for quantitative blood flow registration such as phase-mapping (a two-dimensional space-resolved technique with a time-averaged measurement of blood flow) or RACE (real-time acquisition and evaluation of blood flow in one-dimensional space projection) are available for the diagnosis of valvular heart disease. Initial results of grading aortic valve stenosis by these methods are shown in comparison to continuous wave Ultrasound-Doppler. Two groups of 15 patients were examined by RACE or phase-mapping, 12 respectively 8 of whom suffered from an aortic valve stenosis. The shape of blood flow profiles as well as grading of aortic valve stenosis show high concordance when comparing the results of MR and Doppler technique. Good reliability and practicability of the demonstrated MR-method are shown. With respect to the results of RACE and phase-mapping the development of an alternative and competing MR-method for the evaluation of valvular heart disease and shunt diagnostics seems possible. (orig.)

  13. Mapping the Superconducting Anti-ferromagnetic C4 Phase in Iron-Pnictides

    Science.gov (United States)

    Stadel, Ryan; Taddei, Keith; Bugaris, Dan; Lapidus, Saul; Claus, Helmut; Phelan, Daniel; Chung, Duck Young; Kanatzidis, Mercouri; Osborn, Raymond; Rosenkranz, Stephan; Chmaissem, Omar

    Following the discovery of the microscopic coexistence of antifermagnetic spin density waves and superconductivity in Ba1-xKxFe2As2 and the low temperature re-entrance to the novel magnetic C4 tetragonal phase in Ba1-xNaxFe2As2, there has been significant interest in developing an understanding of the properties and formation of these phases and analyzing their dependence on temperature and composition in hole-doped 122 alkaline earth metal/iron-pnictides. We describe the mapping of various Ba, Sr, and Ca 122 phase diagrams with systematically controlled levels of hole-doping of alkaline metal onto the alkaline earth metal site, which was investigated via x-ray and neutron diffraction. Our elaborate synthesis, diffraction work, and analysis maps and firmly establishes the C4 phase space in these ternary diagrams as well as the boundary lines that separate the individual phases, and provides natural clues as well as a framework to investigate the stability and formation of the C4 domes that shift location with doping contents in the phase diagrams. Work at Argonne was supported by US DOE, Office of Science, Materials Sciences and Engineering Division.

  14. Tissue Cancellation in Dual Energy Mammography Using a Calibration Phantom Customized for Direct Mapping.

    Science.gov (United States)

    Han, Seokmin; Kang, Dong-Goo

    2014-01-01

    An easily implementable tissue cancellation method for dual energy mammography is proposed to reduce anatomical noise and enhance lesion visibility. For dual energy calibration, the images of an imaging object are directly mapped onto the images of a customized calibration phantom. Each pixel pair of the low and high energy images of the imaging object was compared to pixel pairs of the low and high energy images of the calibration phantom. The correspondence was measured by absolute difference between the pixel values of imaged object and those of the calibration phantom. Then the closest pixel pair of the calibration phantom images is marked and selected. After the calibration using direct mapping, the regions with lesion yielded different thickness from the background tissues. Taking advantage of the different thickness, the visibility of cancerous lesions was enhanced with increased contrast-to-noise ratio, depending on the size of lesion and breast thickness. However, some tissues near the edge of imaged object still remained after tissue cancellation. These remaining residuals seem to occur due to the heel effect, scattering, nonparallel X-ray beam geometry and Poisson distribution of photons. To improve its performance further, scattering and the heel effect should be compensated.

  15. Deep-tissue temperature mapping by multi-illumination photoacoustic tomography aided by a diffusion optical model: a numerical study

    Science.gov (United States)

    Zhou, Yuan; Tang, Eric; Luo, Jianwen; Yao, Junjie

    2018-01-01

    Temperature mapping during thermotherapy can help precisely control the heating process, both temporally and spatially, to efficiently kill the tumor cells and prevent the healthy tissues from heating damage. Photoacoustic tomography (PAT) has been used for noninvasive temperature mapping with high sensitivity, based on the linear correlation between the tissue's Grüneisen parameter and temperature. However, limited by the tissue's unknown optical properties and thus the optical fluence at depths beyond the optical diffusion limit, the reported PAT thermometry usually takes a ratiometric measurement at different temperatures and thus cannot provide absolute measurements. Moreover, ratiometric measurement over time at different temperatures has to assume that the tissue's optical properties do not change with temperatures, which is usually not valid due to the temperature-induced hemodynamic changes. We propose an optical-diffusion-model-enhanced PAT temperature mapping that can obtain the absolute temperature distribution in deep tissue, without the need of multiple measurements at different temperatures. Based on the initial acoustic pressure reconstructed from multi-illumination photoacoustic signals, both the local optical fluence and the optical parameters including absorption and scattering coefficients are first estimated by the optical-diffusion model, then the temperature distribution is obtained from the reconstructed Grüneisen parameters. We have developed a mathematic model for the multi-illumination PAT of absolute temperatures, and our two-dimensional numerical simulations have shown the feasibility of this new method. The proposed absolute temperature mapping method may set the technical foundation for better temperature control in deep tissue in thermotherapy.

  16. Investigating hyperoxic effects in the rat brain using quantitative susceptibility mapping based on MRI phase.

    Science.gov (United States)

    Hsieh, Meng-Chi; Kuo, Li-Wei; Huang, Yun-An; Chen, Jyh-Horng

    2017-02-01

    To test whether susceptibility imaging can detect microvenous oxygen saturation changes, induced by hyperoxia, in the rat brain. A three-dimensional gradient-echo with a flow compensation sequence was used to acquire T2*-weighted images of rat brains during hyperoxia and normoxia. Quantitative susceptibility mapping (QSM) and QSM-based microvenous oxygenation venography were computed from gradient-echo (GRE) phase images and compared between the two conditions. Pulse oxygen saturation (SpO 2 ) in the cortex was examined and compared with venous oxygen saturation (SvO 2 ) estimated by QSM. Oxygen saturation change calculated by a conventional Δ R2* map was also compared with the ΔSvO 2 estimated by QSM. Susceptibilities of five venous and tissue regions were quantified separately by QSM. Venous susceptibility was reduced by nearly 10%, with an SvO 2 shift of 10% during hyperoxia. A hyperoxic effect, confirmed by SpO 2 measurement, resulted in an SvO 2 increase in the cortex. The ΔSvO 2 between hyperoxia and normoxia was consistent with what was estimated by the Δ R2* map in five regions. These findings suggest that a quantitative susceptibility map is a promising technique for SvO 2 measurement. This method may be useful for quantitatively investigating oxygenation-dependent functional MRI studies. Magn Reson Med 77:592-602, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  17. High resolution orientation mapping of secondary phases in ATI 718Plus® alloy

    Directory of Open Access Journals (Sweden)

    Krakow Robert

    2014-01-01

    Full Text Available The polycrystalline superalloy ATI 718Plus ® (hereafter 718Plus has been developed to replace the established alloy Inconel 718 by offering higher temperature capability for applications in gas turbines. The alloy exhibits two secondary phases in the austenitic matrix; it is strengthened by the γ′-phase with η-phase discontinuously precipitated at the grain boundaries. It can be utilized to control grain growth during forging. Generally, hexagonal η phase has been reported to possess a defined crystallographic orientation with the matrix. However, the material studied here exhibits blocky η-phase that has been precipitated and grown during thermo-mechanical processing. Therefore a measurable change in orientation relationship is expected. The standard technique for orientation mapping is electron back-scattered diffraction with spatial resolution of 100 nm. That is insufficient for studying η-phase in 718Plus. By applying high resolution orientation mapping in the transmission electron microscope (Philips CM 300 FEGTEM equipped with a Nanomegas ASTARTM system a resolution of 3 nm was achieved. The indexed diffraction data was analysed using the Matlab Toolbox Mtex. The analysis included grain reconstruction and exclusion of low confidence measurements. The data set allows generating phase boundary maps indicating interfaces characteristics. Quantitative assessment shows that only 19% of the γ-η-interfaces fulfil the orientation relationship.

  18. Automated first-principles mapping for phase-change materials.

    Science.gov (United States)

    Esser, Marc; Maintz, Stefan; Dronskowski, Richard

    2017-04-05

    Plotting materials on bi-coordinate maps according to physically meaningful descriptors has a successful tradition in computational solid-state science spanning more than four decades. Equipped with new ab initio techniques introduced in this work, we generate an improved version of the treasure map for phase-change materials (PCMs) as introduced previously by Lencer et al. which, other than before, charts all industrially used PCMs correctly. Furthermore, we suggest seven new PCM candidates, namely SiSb 4 Te 7 , Si 2 Sb 2 Te 5 , SiAs 2 Te 4 , PbAs 2 Te 4 , SiSb 2 Te 4 , Sn 2 As 2 Te 5 , and PbAs 4 Te 7 , to be used as synthetic targets. To realize aforementioned maps based on orbital mixing (or "hybridization") and ionicity coordinates, structural information was first included into an ab initio numerical descriptor for sp 3 orbital mixing and then generalized beyond high-symmetry structures. In addition, a simple, yet powerful quantum-mechanical ionization measure also including structural information was introduced. Taken together, these tools allow for (automatically) generating materials maps solely relying on first-principles calculations. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  19. An automated method for mapping human tissue permittivities by MRI in hyperthermia treatment planning

    Energy Technology Data Exchange (ETDEWEB)

    Farace, Paolo; Antolini, Renzo [CMBM-ITC, Centro Materiali e Biofisica Medica, 38050 Povo-Trento (Italy); Dipartimento di Fisica and INFM, Universita di Trento, 38050 Povo-Trento (Italy); Pontalti, Rolando; Cristoforetti, Luca [CMBM-ITC, Centro Materiali e Biofisica Medica, 38050 Povo-Trento (Italy); Scarpa, Marina [Dipartimento di Fisica and INFM, Universita di Trento, 38050 Povo-Trento (Italy)

    1997-11-01

    This paper presents an automatic method to obtain tissue complex permittivity values to be used as input data in the computer modelling for hyperthermia treatment planning. Magnetic resonance (MR) images were acquired and the tissue water content was calculated from the signal intensity of the image pixels. The tissue water content was converted into complex permittivity values by monotonic functions based on mixture theory. To obtain a water content map by MR imaging a gradient-echo pulse sequence was used and an experimental procedure was set up to correct for relaxation and radiofrequency field inhomogeneity effects on signal intensity. Two approaches were followed to assign the permittivity values to fat-rich tissues: (i) fat-rich tissue localization by a segmentation procedure followed by assignment of tabulated permittivity values; (ii) water content evaluation by chemical shift imaging followed by permittivity calculation. Tests were performed on phantoms of known water content to establish the reliability of the proposed method. MRI data were acquired and processed pixel-by-pixel according to the outlined procedure. The signal intensity in the phantom images correlated well with water content. Experiments were performed on volunteers' healthy tissue. In particular two anatomical structures were chosen to calculate permittivity maps: the head and the thigh. The water content and electric permittivity values were obtained from the MRI data and compared to others in the literature. A good agreement was found for muscle, cerebrospinal fluid (CSF) and white and grey matter. The advantages of the reported method are discussed in the light of possible application in hyperthermia treatment planning. (author)

  20. An automated method for mapping human tissue permittivities by MRI in hyperthermia treatment planning

    International Nuclear Information System (INIS)

    Farace, Paolo; Antolini, Renzo; Pontalti, Rolando; Cristoforetti, Luca; Scarpa, Marina

    1997-01-01

    This paper presents an automatic method to obtain tissue complex permittivity values to be used as input data in the computer modelling for hyperthermia treatment planning. Magnetic resonance (MR) images were acquired and the tissue water content was calculated from the signal intensity of the image pixels. The tissue water content was converted into complex permittivity values by monotonic functions based on mixture theory. To obtain a water content map by MR imaging a gradient-echo pulse sequence was used and an experimental procedure was set up to correct for relaxation and radiofrequency field inhomogeneity effects on signal intensity. Two approaches were followed to assign the permittivity values to fat-rich tissues: (i) fat-rich tissue localization by a segmentation procedure followed by assignment of tabulated permittivity values; (ii) water content evaluation by chemical shift imaging followed by permittivity calculation. Tests were performed on phantoms of known water content to establish the reliability of the proposed method. MRI data were acquired and processed pixel-by-pixel according to the outlined procedure. The signal intensity in the phantom images correlated well with water content. Experiments were performed on volunteers' healthy tissue. In particular two anatomical structures were chosen to calculate permittivity maps: the head and the thigh. The water content and electric permittivity values were obtained from the MRI data and compared to others in the literature. A good agreement was found for muscle, cerebrospinal fluid (CSF) and white and grey matter. The advantages of the reported method are discussed in the light of possible application in hyperthermia treatment planning. (author)

  1. An automated method for mapping human tissue permittivities by MRI in hyperthermia treatment planning.

    Science.gov (United States)

    Farace, P; Pontalti, R; Cristoforetti, L; Antolini, R; Scarpa, M

    1997-11-01

    This paper presents an automatic method to obtain tissue complex permittivity values to be used as input data in the computer modelling for hyperthermia treatment planning. Magnetic resonance (MR) images were acquired and the tissue water content was calculated from the signal intensity of the image pixels. The tissue water content was converted into complex permittivity values by monotonic functions based on mixture theory. To obtain a water content map by MR imaging a gradient-echo pulse sequence was used and an experimental procedure was set up to correct for relaxation and radiofrequency field inhomogeneity effects on signal intensity. Two approaches were followed to assign the permittivity values to fat-rich tissues: (i) fat-rich tissue localization by a segmentation procedure followed by assignment of tabulated permittivity values; (ii) water content evaluation by chemical shift imaging followed by permittivity calculation. Tests were performed on phantoms of known water content to establish the reliability of the proposed method. MRI data were acquired and processed pixel-by-pixel according to the outlined procedure. The signal intensity in the phantom images correlated well with water content. Experiments were performed on volunteers' healthy tissue. In particular two anatomical structures were chosen to calculate permittivity maps: the head and the thigh. The water content and electric permittivity values were obtained from the MRI data and compared to others in the literature. A good agreement was found for muscle, cerebrospinal fluid (CSF) and white and grey matter. The advantages of the reported method are discussed in the light of possible application in hyperthermia treatment planning.

  2. An automated method for mapping human tissue permittivities by MRI in hyperthermia treatment planning

    Energy Technology Data Exchange (ETDEWEB)

    Farace, Paolo; Antolini, Renzo [CMBM-ITC, Centro Materiali e Biofisica Medica, 38050 Povo-Trento (Italy); Dipartimento di Fisica and INFM, Universita di Trento, 38050 Povo-Trento (Italy); Pontalti, Rolando; Cristoforetti, Luca [CMBM-ITC, Centro Materiali e Biofisica Medica, 38050 Povo-Trento (Italy); Scarpa, Marina [Dipartimento di Fisica and INFM, Universita di Trento, 38050 Povo-Trento (Italy)

    1997-11-01

    This paper presents an automatic method to obtain tissue complex permittivity values to be used as input data in the computer modelling for hyperthermia treatment planning. Magnetic resonance (MR) images were acquired and the tissue water content was calculated from the signal intensity of the image pixels. The tissue water content was converted into complex permittivity values by monotonic functions based on mixture theory. To obtain a water content map by MR imaging a gradient-echo pulse sequence was used and an experimental procedure was set up to correct for relaxation and radiofrequency field inhomogeneity effects on signal intensity. Two approaches were followed to assign the permittivity values to fat-rich tissues: (i) fat-rich tissue localization by a segmentation procedure followed by assignment of tabulated permittivity values; (ii) water content evaluation by chemical shift imaging followed by permittivity calculation. Tests were performed on phantoms of known water content to establish the reliability of the proposed method. MRI data were acquired and processed pixel-by-pixel according to the outlined procedure. The signal intensity in the phantom images correlated well with water content. Experiments were performed on volunteers' healthy tissue. In particular two anatomical structures were chosen to calculate permittivity maps: the head and the thigh. The water content and electric permittivity values were obtained from the MRI data and compared to others in the literature. A good agreement was found for muscle, cerebrospinal fluid (CSF) and white and grey matter. The advantages of the reported method are discussed in the light of possible application in hyperthermia treatment planning. (author)

  3. Two-phase flow operational maps for multi-microchannel evaporators

    International Nuclear Information System (INIS)

    Szczukiewicz, Sylwia; Borhani, Navid; Thome, John Richard

    2013-01-01

    Highlights: • New operational maps for several different micro-evaporators are presented. • Inlet micro-orifices prevented flow instability, back flow, and flow maldistribution. • Eight different operating regimes were distinguished. • The flashing two-phase flow without back flow operating regime is preferred. -- Abstract: The current paper presents new operational maps for several different multi-microchannel evaporators, with and without any inlet restrictions (micro-orifices), for the two-phase flow of refrigerants R245fa, R236fa, and R1234ze(E). The test fluids flowed in 67 parallel channels, each having a cross-sectional area of 100 × 100 μm 2 . In order to emulate the power dissipated by active components in a 3D CMOS CPU chip, two aluminium microheaters were sputtered onto the back-side of the test section providing a 0.5 cm 2 each. Without any inlet restrictions in the micro-evaporator, significant parallel channel flow instabilities, vapor back flow, and flow maldistribution led to high-amplitude and high-frequency temperature and pressure oscillations. Such undesired phenomena were then prevented by placing restrictions at the inlet of each channel. High-speed flow visualization distinguished eight different operating regimes of the two-phase flow depending on the tested operating conditions. Therefore, the preferred operating regimes can be easily traced. In particular, flashing two-phase flow without back flow appeared to be the best operating regime without any flow and temperature instabilities

  4. An imaging colorimeter for noncontact tissue color mapping.

    Science.gov (United States)

    Balas, C

    1997-06-01

    There has been a considerable effort in several medical fields, for objective color analysis and characterization of biological tissues. Conventional colorimeters have proved inadequate for this purpose, since they do not provide spatial color information and because the measuring procedure randomly affects the color of the tissue. In this paper an imaging colorimeter is presented, where the nonimaging optical photodetector of colorimeters is replaced with the charge-coupled device (CCD) sensor of a color video camera, enabling the independent capturing of the color information for any spatial point within its field-of-view. Combining imaging and colorimetry methods, the acquired image is calibrated and corrected, under several ambient light conditions, providing noncontact reproducible color measurements and mapping, free of the errors and the limitations present in conventional colorimeters. This system was used for monitoring of blood supply changes of psoriatic plaques, that have undergone Psoralens and ultraviolet-A radiation (PUVA) therapy, where reproducible and reliable measurements were demonstrated. These features highlight the potential of the imaging colorimeters as clinical and research tools for the standardization of clinical diagnosis and for the objective evaluation of treatment effectiveness.

  5. Optical method for mapping the transverse phase space of a charged particle beam

    International Nuclear Information System (INIS)

    Fiorito, R.B.; Shkvarunets, A.G.; O'Shea, P.G.

    2002-01-01

    We are developing an all optical method to map the transverse phase space map of a charged particle beam. Our technique employs OTR interferometry (OTRI) in combination with a scanning pinhole to make local orthogonal (x,y) divergence and trajectory angle measurements as function of position within the transverse profile of the beam. The localized data allows a reconstruction of the horizontal and vertical phase spaces of the beam. We have also demonstrated how single and multiple pinholes can in principle be used to make such measurements simultaneously

  6. Full-Field Calibration of Color Camera Chromatic Aberration using Absolute Phase Maps.

    Science.gov (United States)

    Liu, Xiaohong; Huang, Shujun; Zhang, Zonghua; Gao, Feng; Jiang, Xiangqian

    2017-05-06

    The refractive index of a lens varies for different wavelengths of light, and thus the same incident light with different wavelengths has different outgoing light. This characteristic of lenses causes images captured by a color camera to display chromatic aberration (CA), which seriously reduces image quality. Based on an analysis of the distribution of CA, a full-field calibration method based on absolute phase maps is proposed in this paper. Red, green, and blue closed sinusoidal fringe patterns are generated, consecutively displayed on an LCD (liquid crystal display), and captured by a color camera from the front viewpoint. The phase information of each color fringe is obtained using a four-step phase-shifting algorithm and optimum fringe number selection method. CA causes the unwrapped phase of the three channels to differ. These pixel deviations can be computed by comparing the unwrapped phase data of the red, blue, and green channels in polar coordinates. CA calibration is accomplished in Cartesian coordinates. The systematic errors introduced by the LCD are analyzed and corrected. Simulated results show the validity of the proposed method and experimental results demonstrate that the proposed full-field calibration method based on absolute phase maps will be useful for practical software-based CA calibration.

  7. Comparing 511 keV Attenuation Maps Obtained from Different Energy Mapping Methods for CT Based Attenuation Correction of PET Data

    Directory of Open Access Journals (Sweden)

    Maryam Shirmohammad

    2008-06-01

    Full Text Available Introduction:  The  advent  of  dual-modality  PET/CT  scanners  has  revolutionized  clinical  oncology  by  improving lesion localization and facilitating treatment planning for radiotherapy. In addition, the use of  CT images for CT-based attenuation correction (CTAC decreases the overall scanning time and creates  a noise-free  attenuation  map  (6map.  CTAC  methods  include  scaling,  segmentation,  hybrid  scaling/segmentation, bilinear and dual energy methods. All CTAC methods require the transformation  of CT Hounsfield units (HU to linear attenuation coefficients (LAC at 511 keV. The aim of this study is  to compare the results of implementing different methods of energy mapping in PET/CT scanners.   Materials and Methods: This study was conducted in 2 phases, the first phase in a phantom and the  second  one  on  patient  data.  To  perform  the  first  phase,  a  cylindrical  phantom  with  different  concentrations of K2HPO4 inserts was CT scanned and energy mapping methods were implemented on  it. For performing the second phase, different energy  mapping  methods  were implemented on several  clinical studies and compared to the transmission (TX image derived using Ga-68 radionuclide source  acquired on the GE Discovery LS PET/CT scanner.   Results: An ROI analysis was performed on different positions of the resultant 6maps and the average  6value of each ROI was compared to the reference value. The results of the 6maps obtained for 511 keV  compared to the theoretical  values showed that in the phantom for low  concentrations  of K 2 HPO 4 all  these  methods  produce  511  keV  attenuation  maps  with  small  relative  difference  compared  to  gold  standard. The relative difference for scaling, segmentation, hybrid, bilinear and dual energy methods was  4.92,  3.21,  4.43,  2.24  and  2.29%,  respectively.  Although  for  high  concentration

  8. Phase mapping of aging process in InN nanostructures: oxygen incorporation and the role of the zinc blende phase

    International Nuclear Information System (INIS)

    Gonzalez, D; Lozano, J G; Herrera, M; Morales, F M; GarcIa, R; Ruffenach, S; Briot, O

    2010-01-01

    Uncapped InN nanostructures undergo a deleterious natural aging process at ambient conditions by oxygen incorporation. The phases involved in this process and their localization is mapped by transmission electron microscopy (TEM)-related techniques. The parent wurtzite InN (InN-w) phase disappears from the surface and gradually forms a highly textured cubic layer that completely wraps up a InN-w nucleus which still remains from the original single-crystalline quantum dots. The good reticular relationships between the different crystals generate low misfit strains and explain the apparent easiness for phase transformations at room temperature and pressure conditions, but also disable the classical methods to identify phases and grains from TEM images. The application of the geometrical phase algorithm in order to form numerical moire mappings and RGB multilayered image reconstructions allows us to discern among the different phases and grains formed inside these nanostructures. Samples aged for shorter times reveal the presence of metastable InN:O zinc blende (zb) volumes, which act as the intermediate phase between the initial InN-w and the most stable cubic In 2 O 3 end phase. These cubic phases are highly twinned with a proportion of 50:50 between both orientations. We suggest that the existence of the intermediate InN:O-zb phase should be seriously considered to understand the reason for the widely scattered reported fundamental properties of thought to be InN-w, as its bandgap or superconductivity.

  9. A study of Two-Phase Flow Regime Maps in Vertical and Horizontal Pipes

    International Nuclear Information System (INIS)

    Kim, Kyung Doo; Kang, Doo Hyuk

    2007-10-01

    A safety analysis code to design a pressurized water reactor and to obtain the licences including entire proprietary rights is under development in domestic research and development project. The purpose and scope of this report is to develop the flow regimes related models for inter-phase friction, wall frictions, wall heat transfer, and inter-phase heat and mass transfer in two-phase three-field equations. In order to choose choose the flow regime criteria, we have investigated various exiting best-estimate T/H codes in this chapter 2. They are the RELAP5-3D, TRAC-M, CATHARE, MARS codes. Around 500 references used in these codes have been collected and reviewed. Also we have investigated eleven papers in detail. In chapter 3, based on the selected flow regimes, the flow regime maps for a gas-liquid flow in horizontal and vertical tubes have decided including the mechanisms of flow regime transition regions. Conclusively, the process will be presented for choosing the best flow regime maps which occur in gas-liquid two-phase flow in horizontal and vertical pipes. We will look forward to decide the constitutive relations based upon the flow regime maps that are determined in this works. The constitutive relations will be used for the code under development

  10. Order in the turbulent phase of globally coupled maps

    International Nuclear Information System (INIS)

    Perez, G.; Sinha, S.; Cerdeira, H.A.

    1991-04-01

    The very surprising broad peaks seen in the power spectra of the mean field in a globally coupled map system, indicating subtle coherences between the elements even in the ''turbulent'' phase, are investigated in detail with respect to number of elements coupled, nonlinearity and global coupling strength. We find that the peaks are determined by two distinct components: effective renormalization of the nonlinearity parameter in the local mapping and the strength of the mean field iteration term. We also demonstrate the influence of background noise on the peaks - which is quite counterintuitive, as the peaks become sharper with increase in strength of noise, up to a certain critical noise strength. (author). 11 refs, 10 figs

  11. Acceleration of tissue phase mapping by k-t BLAST: a detailed analysis of the influence of k-t-BLAST for the quantification of myocardial motion at 3T

    Directory of Open Access Journals (Sweden)

    Nienhaus G Ulrich

    2011-01-01

    Full Text Available Abstract Background The assessment of myocardial motion with tissue phase mapping (TPM provides high spatiotemporal resolution and quantitative motion information in three directions. Today, whole volume coverage of the heart by TPM encoding at high spatial and temporal resolution is limited by long data acquisition times. Therefore, a significant increase in imaging speed without deterioration of the quantitative motion information is required. For this purpose, the k-t BLAST acceleration technique was combined with TPM black-blood functional imaging of the heart. Different k-t factors were evaluated with respect to their impact on the quantitative assessment of cardiac motion. Results It is demonstrated that a k-t BLAST factor of two can be used with a marginal, but statistically significant deterioration of the quantitative motion data. Further increasing the k-t acceleration causes substantial alteration of the peak velocities and the motion pattern, but the temporal behavior of the contraction is well maintained up to an acceleration factor of six. Conclusions The application of k-t BLAST for the acceleration of TPM appears feasible. A reduction of the acquisition time of almost 45% could be achieved without substantial loss of quantitative motion information.

  12. Dual-energy digital mammography: Calibration and inverse-mapping techniques to estimate calcification thickness and glandular-tissue ratio

    International Nuclear Information System (INIS)

    Kappadath, S. Cheenu; Shaw, Chris C.

    2003-01-01

    Breast cancer may manifest as microcalcifications in x-ray mammography. Small microcalcifications, essential to the early detection of breast cancer, are often obscured by overlapping tissue structures. Dual-energy imaging, where separate low- and high-energy images are acquired and synthesized to cancel the tissue structures, may improve the ability to detect and visualize microcalcifications. Transmission measurements at two different kVp values were made on breast-tissue-equivalent materials under narrow-beam geometry using an indirect flat-panel mammographic imager. The imaging scenario consisted of variable aluminum thickness (to simulate calcifications) and variable glandular ratio (defined as the ratio of the glandular-tissue thickness to the total tissue thickness) for a fixed total tissue thickness--the clinical situation of microcalcification imaging with varying tissue composition under breast compression. The coefficients of the inverse-mapping functions used to determine material composition from dual-energy measurements were calculated by a least-squares analysis. The linear function poorly modeled both the aluminum thickness and the glandular ratio. The inverse-mapping functions were found to vary as analytic functions of second (conic) or third (cubic) order. By comparing the model predictions with the calibration values, the root-mean-square residuals for both the cubic and the conic functions were ∼50 μm for the aluminum thickness and ∼0.05 for the glandular ratio

  13. NIH Scientists Map Genetic Changes That Drive Tumors in a Common Pediatric Soft-Tissue Cancer

    Science.gov (United States)

    ... Press Release NIH scientists map genetic changes that drive tumors in a common pediatric soft-tissue cancer ... of Health FOLLOW US Facebook Twitter Instagram YouTube Google+ LinkedIn GovDelivery RSS CONTACT INFORMATION Contact Us LiveHelp ...

  14. Theoretical and Experimental Estimations of Volumetric Inductive Phase Shift in Breast Cancer Tissue

    Science.gov (United States)

    González, C. A.; Lozano, L. M.; Uscanga, M. C.; Silva, J. G.; Polo, S. M.

    2013-04-01

    Impedance measurements based on magnetic induction for breast cancer detection has been proposed in some studies. This study evaluates theoretical and experimentally the use of a non-invasive technique based on magnetic induction for detection of patho-physiological conditions in breast cancer tissue associated to its volumetric electrical conductivity changes through inductive phase shift measurements. An induction coils-breast 3D pixel model was designed and tested. The model involves two circular coils coaxially centered and a human breast volume centrally placed with respect to the coils. A time-harmonic numerical simulation study addressed the effects of frequency-dependent electrical properties of tumoral tissue on the volumetric inductive phase shift of the breast model measured with the circular coils as inductor and sensor elements. Experimentally; five female volunteer patients with infiltrating ductal carcinoma previously diagnosed by the radiology and oncology departments of the Specialty Clinic for Women of the Mexican Army were measured by an experimental inductive spectrometer and the use of an ergonomic inductor-sensor coil designed to estimate the volumetric inductive phase shift in human breast tissue. Theoretical and experimental inductive phase shift estimations were developed at four frequencies: 0.01, 0.1, 1 and 10 MHz. The theoretical estimations were qualitatively in agreement with the experimental findings. Important increments in volumetric inductive phase shift measurements were evident at 0.01MHz in theoretical and experimental observations. The results suggest that the tested technique has the potential to detect pathological conditions in breast tissue associated to cancer by non-invasive monitoring. Further complementary studies are warranted to confirm the observations.

  15. Mapping and characterization of iron compounds in Alzheimer's tissue

    International Nuclear Information System (INIS)

    Collingwood, Joanna; Dobson, Jon

    2006-01-01

    Understanding the management of iron in the brain is of great importance in the study of neurodegeneration, where regional iron overload is frequently evident. A variety of approaches have been employed, from quantifying iron in various anatomical structures, to identifying genetic risk factors related to iron metabolism, and exploring chelation approaches to tackle iron overload in neurodegenerative disease. However, the ease with which iron can change valence state ensures that it is present in vivo in a wide variety of forms, both soluble and insoluble. Here, we review recent developments in approaches to locate and identify iron compounds in neurodegenerative tissue. In addition to complementary techniques that allow us to quantify and identify iron compounds using magnetometry, extraction, and electron microscopy, we are utilizing a powerful combined mapping/characterization approach with synchrotron X-rays. This has enabled the location and characterization of iron accumulations containing magnetite and ferritin in human Alzheimer's disease (AD) brain tissue sections in situ at micron-resolution. It is hoped that such approaches will contribute to our understanding of the role of unusual iron accumulations in disease pathogenesis, and optimise the potential to use brain iron as a clinical biomarker for early detection and diagnosis.

  16. Comparison of tissue viability imaging and colorimetry: skin blanching.

    Science.gov (United States)

    Zhai, Hongbo; Chan, Heidi P; Farahmand, Sara; Nilsson, Gert E; Maibach, Howard I

    2009-02-01

    Operator-independent assessment of skin blanching is important in the development and evaluation of topically applied steroids. Spectroscopic instruments based on hand-held probes, however, include elements of operator dependence such as difference in applied pressure and probe misalignment, while laser Doppler-based methods are better suited for demonstration of skin vasodilatation than for vasoconstriction. To demonstrate the potential of the emerging technology of Tissue Viability Imaging (TiVi) in the objective and operator-independent assessment of skin blanching. The WheelsBridge TiVi600 Tissue Viability Imager was used for quantification of human skin blanching with the Minolta chromameter CR 200 as an independent colorimeter reference method. Desoximetasone gel 0.05% was applied topically on the volar side of the forearm under occlusion for 6 h in four healthy adults. In a separate study, the induction of blanching in the occlusion phase was mapped using a transparent occlusion cover. The relative uncertainty in the blanching estimate produced by the Tissue Viability Imager was about 5% and similar to that of the chromameter operated by a single user and taking the a(*) parameter as a measure of blanching. Estimation of skin blanching could also be performed in the presence of a transient paradoxical erythema, using the integrated TiVi software. The successive induction of skin blanching during the occlusion phase could readily be mapped by the Tissue Viability Imager. TiVi seems to be suitable for operator-independent and remote mapping of human skin blanching, eliminating the main disadvantages of methods based on hand-held probes.

  17. Phase mapping of radionuclide gated biventriculograms in patients with sustained ventricular tachycardia or Wolff-Parkinson-White syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Le Guludec, D.; Bourguignon, M.; Sebag, C.; Valette, H.; Sirinelli, A.; Davy, J.M.; Syrota, A.; Motte, G.

    1987-01-01

    Accuracy of Fourier phase mapping of radionuclide gated biventriculograms in detecting the origin of abnormal ventricular activation was studied during ventricular tachycardia or preexcitation. Group I included six patients suffering from clinical recurrent VT; 3 gated blood pool studies were acquired for each patient: during sinus rhythm, right ventricular pacing, and induced sustained VT-Group II included seven patients with Wolff-Parkinson-White syndrome and recurrent paroxysmal tachycardia; 3 gated blood pool studies were acquired for each patient: during sinus rhythm, right atrial pacing and orthodromic reciprocating tachycardia. Each acquisition lasted 5 min, in 30 degrees-40 degrees left anterior oblique projection. In Group I, the Fourier phase mapping was consistent with QRS morphology and axis during VT (5/6), except in one patient with LV aneurysm and LBBB electrical pattern during VT. Origin of VT on phase mapping was located in the right ventricle (n = 2) or in left ventricle (n = 4), at the border of wall motion abnormalities each time they existed (5/6). In Group II, the phase advance correlated with the location of the accessory pathway determined by ECG and endocardial mapping (n = 6) and per-operative epicardial mapping (n = 1). Discrimination between anterior and posterior localization of paraseptal pathways and location of intermittent preexcitation was not possible. We conclude that Fourier phase mapping is an accurate method for locating the origin of VT and determining its etiology. It can help locate the site of ventricular preexcitation in patients with only one accessory pathway; its accuracy in locating multiple accessory pathways remains unknown.

  18. Phase mapping of radionuclide gated biventriculograms in patients with sustained ventricular tachycardia or Wolff-Parkinson-White syndrome

    International Nuclear Information System (INIS)

    Le Guludec, D.; Bourguignon, M.; Sebag, C.; Valette, H.; Sirinelli, A.; Davy, J.M.; Syrota, A.; Motte, G.

    1987-01-01

    Accuracy of Fourier phase mapping of radionuclide gated biventriculograms in detecting the origin of abnormal ventricular activation was studied during ventricular tachycardia or preexcitation. Group I included six patients suffering from clinical recurrent VT; 3 gated blood pool studies were acquired for each patient: during sinus rhythm, right ventricular pacing, and induced sustained VT-Group II included seven patients with Wolff-Parkinson-White syndrome and recurrent paroxysmal tachycardia; 3 gated blood pool studies were acquired for each patient: during sinus rhythm, right atrial pacing and orthodromic reciprocating tachycardia. Each acquisition lasted 5 min, in 30 degrees-40 degrees left anterior oblique projection. In Group I, the Fourier phase mapping was consistent with QRS morphology and axis during VT (5/6), except in one patient with LV aneurysm and LBBB electrical pattern during VT. Origin of VT on phase mapping was located in the right ventricle (n = 2) or in left ventricle (n = 4), at the border of wall motion abnormalities each time they existed (5/6). In Group II, the phase advance correlated with the location of the accessory pathway determined by ECG and endocardial mapping (n = 6) and per-operative epicardial mapping (n = 1). Discrimination between anterior and posterior localization of paraseptal pathways and location of intermittent preexcitation was not possible. We conclude that Fourier phase mapping is an accurate method for locating the origin of VT and determining its etiology. It can help locate the site of ventricular preexcitation in patients with only one accessory pathway; its accuracy in locating multiple accessory pathways remains unknown

  19. A two-phase model of plantar tissue: a step toward prediction of diabetic foot ulceration.

    Science.gov (United States)

    Sciumè, G; Boso, D P; Gray, W G; Cobelli, C; Schrefler, B A

    2014-11-01

    A new computational model, based on the thermodynamically constrained averaging theory, has been recently proposed to predict tumor initiation and proliferation. A similar mathematical approach is proposed here as an aid in diabetic ulcer prevention. The common aspects at the continuum level are the macroscopic balance equations governing the flow of the fluid phase, diffusion of chemical species, tissue mechanics, and some of the constitutive equations. The soft plantar tissue is modeled as a two-phase system: a solid phase consisting of the tissue cells and their extracellular matrix, and a fluid one (interstitial fluid and dissolved chemical species). The solid phase may become necrotic depending on the stress level and on the oxygen availability in the tissue. Actually, in diabetic patients, peripheral vascular disease impacts tissue necrosis; this is considered in the model via the introduction of an effective diffusion coefficient that governs transport of nutrients within the microvasculature. The governing equations of the mathematical model are discretized in space by the finite element method and in time domain using the θ-Wilson Method. While the full mathematical model is developed in this paper, the example is limited to the simulation of several gait cycles of a healthy foot. Copyright © 2014 John Wiley & Sons, Ltd.

  20. In-situ Characterization and Mapping of Iron Compounds in Alzheimer's Tissue

    International Nuclear Information System (INIS)

    Collingwood, J.F.; Mikhaylova, A.; Davidson, M.; Batich, C.; Streit, W.J.; Terry, J.; Dobson, J.

    2005-01-01

    There is a well-established link between iron overload in the brain and pathology associated with neurodegeneration in a variety of disorders such as Alzheimer's (AD), Parkinson's (PD) and Huntington's (HD) diseases. This association was first discovered in AD by Goodman in 1953, where, in addition to abnormally high concentrations of iron in autopsy brain tissue, iron has also been shown to accumulate at sites of brain pathology such as senile plaques. However, since this discovery, progress in understanding the origin, role and nature of iron compounds associated with neurodegeneration has been slow. Here we report, for the first time, the location and characterization of iron compounds in human AD brain tissue sections. Iron fluorescence was mapped over a frontal-lobe tissue section from an Alzheimer's patient, and anomalous iron concentrations were identified using synchrotron X-ray absorption techniques at 5 (micro)m spatial resolution. Concentrations of ferritin and magnetite, a magnetic iron oxide potentially indicating disrupted brain-iron metabolism, were evident. These results demonstrate a practical means of correlating iron compounds and disease pathology in-situ and have clear implications for disease pathogenesis and potential therapies.

  1. Brain functional BOLD perturbation modelling for forward fMRI and inverse mapping

    Science.gov (United States)

    Robinson, Jennifer; Calhoun, Vince

    2018-01-01

    Purpose To computationally separate dynamic brain functional BOLD responses from static background in a brain functional activity for forward fMRI signal analysis and inverse mapping. Methods A brain functional activity is represented in terms of magnetic source by a perturbation model: χ = χ0 +δχ, with δχ for BOLD magnetic perturbations and χ0 for background. A brain fMRI experiment produces a timeseries of complex-valued images (T2* images), whereby we extract the BOLD phase signals (denoted by δP) by a complex division. By solving an inverse problem, we reconstruct the BOLD δχ dataset from the δP dataset, and the brain χ distribution from a (unwrapped) T2* phase image. Given a 4D dataset of task BOLD fMRI, we implement brain functional mapping by temporal correlation analysis. Results Through a high-field (7T) and high-resolution (0.5mm in plane) task fMRI experiment, we demonstrated in detail the BOLD perturbation model for fMRI phase signal separation (P + δP) and reconstructing intrinsic brain magnetic source (χ and δχ). We also provided to a low-field (3T) and low-resolution (2mm) task fMRI experiment in support of single-subject fMRI study. Our experiments show that the δχ-depicted functional map reveals bidirectional BOLD χ perturbations during the task performance. Conclusions The BOLD perturbation model allows us to separate fMRI phase signal (by complex division) and to perform inverse mapping for pure BOLD δχ reconstruction for intrinsic functional χ mapping. The full brain χ reconstruction (from unwrapped fMRI phase) provides a new brain tissue image that allows to scrutinize the brain tissue idiosyncrasy for the pure BOLD δχ response through an automatic function/structure co-localization. PMID:29351339

  2. Brain functional BOLD perturbation modelling for forward fMRI and inverse mapping.

    Science.gov (United States)

    Chen, Zikuan; Robinson, Jennifer; Calhoun, Vince

    2018-01-01

    To computationally separate dynamic brain functional BOLD responses from static background in a brain functional activity for forward fMRI signal analysis and inverse mapping. A brain functional activity is represented in terms of magnetic source by a perturbation model: χ = χ0 +δχ, with δχ for BOLD magnetic perturbations and χ0 for background. A brain fMRI experiment produces a timeseries of complex-valued images (T2* images), whereby we extract the BOLD phase signals (denoted by δP) by a complex division. By solving an inverse problem, we reconstruct the BOLD δχ dataset from the δP dataset, and the brain χ distribution from a (unwrapped) T2* phase image. Given a 4D dataset of task BOLD fMRI, we implement brain functional mapping by temporal correlation analysis. Through a high-field (7T) and high-resolution (0.5mm in plane) task fMRI experiment, we demonstrated in detail the BOLD perturbation model for fMRI phase signal separation (P + δP) and reconstructing intrinsic brain magnetic source (χ and δχ). We also provided to a low-field (3T) and low-resolution (2mm) task fMRI experiment in support of single-subject fMRI study. Our experiments show that the δχ-depicted functional map reveals bidirectional BOLD χ perturbations during the task performance. The BOLD perturbation model allows us to separate fMRI phase signal (by complex division) and to perform inverse mapping for pure BOLD δχ reconstruction for intrinsic functional χ mapping. The full brain χ reconstruction (from unwrapped fMRI phase) provides a new brain tissue image that allows to scrutinize the brain tissue idiosyncrasy for the pure BOLD δχ response through an automatic function/structure co-localization.

  3. Effects of tissue susceptibility on brain temperature mapping.

    Science.gov (United States)

    Maudsley, Andrew A; Goryawala, Mohammed Z; Sheriff, Sulaiman

    2017-02-01

    A method for mapping of temperature over a large volume of the brain using volumetric proton MR spectroscopic imaging has been implemented and applied to 150 normal subjects. Magnetic susceptibility-induced frequency shifts in gray- and white-matter regions were measured and included as a correction in the temperature mapping calculation. Additional sources of magnetic susceptibility variations of the individual metabolite resonance frequencies were also observed that reflect the cellular-level organization of the brain metabolites, with the most notable differences being attributed to changes of the N-Acetylaspartate resonance frequency that reflect the intra-axonal distribution and orientation of the white-matter tracts with respect to the applied magnetic field. These metabolite-specific susceptibility effects are also shown to change with age. Results indicate no change of apparent brain temperature with age from 18 to 84 years old, with a trend for increased brain temperature throughout the cerebrum in females relative for males on the order of 0.1°C; slightly increased temperatures in the left hemisphere relative to the right; and a lower temperature of 0.3°C in the cerebellum relative to that of cerebral white-matter. This study presents a novel acquisition method for noninvasive measurement of brain temperature that is of potential value for diagnostic purposes and treatment monitoring, while also demonstrating limitations of the measurement due to the confounding effects of tissue susceptibility variations. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Cardiovascular magnetic resonance frontiers: Tissue characterisation with mapping

    Directory of Open Access Journals (Sweden)

    Rebecca Schofield

    2016-11-01

    Full Text Available The clinical use of cardiovascular magnetic resonance (CMR imaging has expanded rapidly over the last decade. Its role in cardiac morphological and functional assessment is established, with perfusion and late gadolinium enhancement (LGE imaging for scar increasingly used in day-to-day clinical decision making. LGE allows a virtual histological assessment of the myocardium, with the pattern of scar suggesting disease aetiology, and the extent of predicting risk. However, even combined, the full range of pathological processes occurring in the myocardium are not interrogated. Mapping is a new frontier where the intrinsic magnetic properties of heart muscle are measured to probe further. T1, T2 and T2* mapping measures the three fundamental tissue relaxation rate constants before contrast, and the extracellular volume (ECV after contrast. These are displayed in colour, often providing an immediate appreciation of pathology. These parameters are differently sensitive to pathologies. Iron (cardiac siderosis, intramyocardial haemorrhage makes T1, T2 and T2* fall. T2 also falls with fat infiltration (Fabry disease. T2 increases with oedema (acute infarction, takotsubo cardiomyopathy, myocarditis, rheumatological disease. Native T1 increases with fibrosis, oedema and amyloid. Some of these changes are large (e.g. iron, oedema, amyloid, others more modest (diffuse fibrosis. They can be used to detect early disease, distinguish aetiology and, in some circumstances, guide therapy. In this review, we discuss these processes, illustrating clinical application and future advances.

  5. Energy content of stormtime ring current from phase space mapping simulations

    International Nuclear Information System (INIS)

    Chen, M.W.; Schulz, M.; Lyons, L.R.

    1993-01-01

    The authors perform a model study to account for the increase in energy content of the trapped-particle population which occurs during the main phase of major geomagnetic storms. They consider stormtime particle transport in the equatorial region of the magnetosphere. They start with a phase space distribution of the ring current before the storm, created by a steady state transport model. They then use a previously developed guiding center particle simulation to map the stormtime ring current phase space, following Liouville's theorem. This model is able to account for the ten to twenty fold increase in energy content of magnetospheric ions during the storm

  6. Classical and quantum investigations of four-dimensional maps with a mixed phase space

    International Nuclear Information System (INIS)

    Richter, Martin

    2012-01-01

    Systems with more than two degrees of freedom are of fundamental importance for the understanding of problems ranging from celestial mechanics to molecules. Due to the dimensionality the classical phase-space structure of such systems is more difficult to understand than for systems with two or fewer degrees of freedom. This thesis aims for a better insight into the classical as well as the quantum mechanics of 4D mappings representing driven systems with two degrees of freedom. In order to analyze such systems, we introduce 3D sections through the 4D phase space which reveal the regular and chaotic structures. We introduce these concepts by means of three example mappings of increasing complexity. After a classical analysis the systems are investigated quantum mechanically. We focus especially on two important aspects: First, we address quantum mechanical consequences of the classical Arnold web and demonstrate how quantum mechanics can resolve this web in the semiclassical limit. Second, we investigate the quantum mechanical tunneling couplings between regular and chaotic regions in phase space. We determine regular-to-chaotic tunneling rates numerically and extend the fictitious integrable system approach to higher dimensions for their prediction. Finally, we study resonance-assisted tunneling in 4D maps.

  7. Mapping of Mechanical Strains and Stresses around Quiescent Engineered Three-Dimensional Epithelial Tissues

    Science.gov (United States)

    Gjorevski, Nikolce; Nelson, Celeste M.

    2012-01-01

    Understanding how physical signals guide biological processes requires qualitative and quantitative knowledge of the mechanical forces generated and sensed by cells in a physiologically realistic three-dimensional (3D) context. Here, we used computational modeling and engineered epithelial tissues of precise geometry to define the experimental parameters that are required to measure directly the mechanical stress profile of 3D tissues embedded within native type I collagen. We found that to calculate the stresses accurately in these settings, we had to account for mechanical heterogeneities within the matrix, which we visualized and quantified using confocal reflectance and atomic force microscopy. Using this technique, we were able to obtain traction forces at the epithelium-matrix interface, and to resolve and quantify patterns of mechanical stress throughout the surrounding matrix. We discovered that whereas single cells generate tension by contracting and pulling on the matrix, the contraction of multicellular tissues can also push against the matrix, causing emergent compression. Furthermore, tissue geometry defines the spatial distribution of mechanical stress across the epithelium, which communicates mechanically over distances spanning hundreds of micrometers. Spatially resolved mechanical maps can provide insight into the types and magnitudes of physical parameters that are sensed and interpreted by multicellular tissues during normal and pathological processes. PMID:22828342

  8. Differential phase-contrast dark-field electron holography for strain mapping

    Energy Technology Data Exchange (ETDEWEB)

    Denneulin, Thibaud, E-mail: thibaud.denneulin@cemes.fr; Houdellier, Florent, E-mail: florent.houdellier@cemes.fr; Hÿtch, Martin, E-mail: martin.hytch@cemes.fr

    2016-01-15

    Strain mapping is an active area of research in transmission electron microscopy. Here we introduce a dark-field electron holographic technique that shares several aspects in common with both off-axis and in-line holography. Two incident and convergent plane waves are produced in front of the specimen thanks to an electrostatic biprism in the condenser system of a transmission electron microscope. The interference of electron beams diffracted by the illuminated crystal is then recorded in a defocused plane. The differential phase recovered from the hologram is directly proportional to the strain in the sample. The strain can be quantified if the separation of the images due to the defocus is precisely determined. The present technique has the advantage that the derivative of the phase is measured directly which allows us to avoid numerical differentiation. The distribution of the noise in the reconstructed strain maps is isotropic and more homogeneous. This technique was used to investigate different samples: a Si/SiGe superlattice, transistors with SiGe source/drain and epitaxial PZT thin films. - Highlights: • DPC dark-field electron holography is set up with a condenser biprism. • The DPC phase is directly proportional to the lattice deformation. • The technique is illustrated with epitaxial SiGe and Pb(Zr,Ti)O{sub 3} samples. • The defocus allows us to control the strain sensitivity and the spatial resolution. • A solution is proposed to setup this technique with a post-specimen biprism.

  9. SU-G-BRC-15: The Potential Clinical Significance of Dose Mapping Error for Intra- Fraction Dose Mapping for Lung Cancer Patients

    Energy Technology Data Exchange (ETDEWEB)

    Sayah, N [Thomas Cancer Center, Richmond, VA (United States); Weiss, E [Virginia Commonwealth University, Richmond, Virginia (United States); Watkins, W [University of Virginia, Charlottesville, VA (United States); Siebers, J [University of Virginia Health System, Charlottesville, VA (United States)

    2016-06-15

    Purpose: To evaluate the dose-mapping error (DME) inherent to conventional dose-mapping algorithms as a function of dose-matrix resolution. Methods: As DME has been reported to be greatest where dose-gradients overlap tissue-density gradients, non-clinical 66 Gy IMRT plans were generated for 11 lung patients with the target edge defined as the maximum 3D density gradient on the 0% (end of inhale) breathing phase. Post-optimization, Beams were copied to 9 breathing phases. Monte Carlo dose computed (with 2*2*2 mm{sup 3} resolution) on all 10 breathing phases was deformably mapped to phase 0% using the Monte Carlo energy-transfer method with congruent mass-mapping (EMCM); an externally implemented tri-linear interpolation method with voxel sub-division; Pinnacle’s internal (tri-linear) method; and a post-processing energy-mass voxel-warping method (dTransform). All methods used the same base displacement-vector-field (or it’s pseudo-inverse as appropriate) for the dose mapping. Mapping was also performed at 4*4*4 mm{sup 3} by merging adjacent dose voxels. Results: Using EMCM as the reference standard, no clinically significant (>1 Gy) DMEs were found for the mean lung dose (MLD), lung V20Gy, or esophagus dose-volume indices, although MLD and V20Gy were statistically different (2*2*2 mm{sup 3}). Pinnacle-to-EMCM target D98% DMEs of 4.4 and 1.2 Gy were observed ( 2*2*2 mm{sup 3}). However dTransform, which like EMCM conserves integral dose, had DME >1 Gy for one case. The root mean square RMS of the DME for the tri-linear-to- EMCM methods was lower for the smaller voxel volume for the tumor 4D-D98%, lung V20Gy, and cord D1%. Conclusion: When tissue gradients overlap with dose gradients, organs-at-risk DME was statistically significant but not clinically significant. Target-D98%-DME was deemed clinically significant for 2/11 patients (2*2*2 mm{sup 3}). Since tri-linear RMS-DME between EMCM and tri-linear was reduced at 2*2*2 mm{sup 3}, use of this resolution is

  10. Critical properties of phase transitions in lattices of coupled logistic maps

    International Nuclear Information System (INIS)

    Marcq, Philippe; Chate, Hugues; Manneville, Paul

    2006-01-01

    We numerically demonstrate that collective bifurcations in two-dimensional lattices of locally coupled logistic maps share most of the defining features of equilibrium second-order phase transitions. Our simulations suggest that these transitions between distinct collective dynamical regimes belong to the universality class of Miller and Huse model with synchronous update. (author)

  11. Quantum Geometric Phase in Majorana's Stellar Representation: Mapping onto a Many-Body Aharonov-Bohm Phase

    Science.gov (United States)

    Bruno, Patrick

    2012-06-01

    The (Berry-Aharonov-Anandan) geometric phase acquired during a cyclic quantum evolution of finite-dimensional quantum systems is studied. It is shown that a pure quantum state in a (2J+1)-dimensional Hilbert space (or, equivalently, of a spin-J system) can be mapped onto the partition function of a gas of independent Dirac strings moving on a sphere and subject to the Coulomb repulsion of 2J fixed test charges (the Majorana stars) characterizing the quantum state. The geometric phase may be viewed as the Aharonov-Bohm phase acquired by the Majorana stars as they move through the gas of Dirac strings. Expressions for the geometric connection and curvature, for the metric tensor, as well as for the multipole moments (dipole, quadrupole, etc.), are given in terms of the Majorana stars. Finally, the geometric formulation of the quantum dynamics is presented and its application to systems with exotic ordering such as spin nematics is outlined.

  12. The Use of Concept Map as a Consolidation Phase Based STAD to Enhance Students’ Comprehension about Environmental Pollution

    Science.gov (United States)

    Nugroho, O. F.; Chandra, D. T.; Sanjaya, Y.; Pendidikan Indonesia, Universitas

    2017-02-01

    The purpose of this study was to improve students’ concept comprehension using concept map as a consolidation phase based STAD. This study was conducted by randomized control group pretest-posttest. Data was collected by using an instrument test to evaluate the effect of concept map as a consolidation phase based STAD on students’understanding about environmental pollution. Data was analyzed using normalized gain (n-gain) and independent t-test. The n-gain analysis shows the increased of students’s understanding about environmental pollution at experimental group arehigher than at the control group. The result of this study showed that students’ comprehension at the experimental class (0,53) higher compared to the control group (0,23). Whilst the t-test analysis shows that there is a significant effect of mapping concept as a consolidation phase based STAD towards students’ concept comprehension. It can be concluded that the implementation of mapping concept based STAD may improve the students’s understanding on science concept.

  13. A multi-frequency sparse hemispherical ultrasound phased array for microbubble-mediated transcranial therapy and simultaneous cavitation mapping.

    Science.gov (United States)

    Deng, Lulu; O'Reilly, Meaghan A; Jones, Ryan M; An, Ran; Hynynen, Kullervo

    2016-12-21

    Focused ultrasound (FUS) phased arrays show promise for non-invasive brain therapy. However, the majority of them are limited to a single transmit/receive frequency and therefore lack the versatility to expose and monitor the treatment volume. Multi-frequency arrays could offer variable transmit focal sizes under a fixed aperture, and detect different spectral content on receive for imaging purposes. Here, a three-frequency (306, 612, and 1224 kHz) sparse hemispherical ultrasound phased array (31.8 cm aperture; 128 transducer modules) was constructed and evaluated for microbubble-mediated transcranial therapy and simultaneous cavitation mapping. The array is able to perform effective electronic beam steering over a volume spanning (-40, 40) and (-30, 50) mm in the lateral and axial directions, respectively. The focal size at the geometric center is approximately 0.9 (2.1) mm, 1.7 (3.9) mm, and 3.1 (6.5) mm in lateral (axial) pressure full width at half maximum (FWHM) at 1224, 612, and 306 kHz, respectively. The array was also found capable of dual-frequency excitation and simultaneous multi-foci sonication, which enables the future exploration of more complex exposure strategies. Passive acoustic mapping of dilute microbubble clouds demonstrated that the point spread function of the receive array has a lateral (axial) intensity FWHM between 0.8-3.5 mm (1.7-11.7 mm) over a volume spanning (-25, 25) mm in both the lateral and axial directions, depending on the transmit/receive frequency combination and the imaging location. The device enabled both half and second harmonic imaging through the intact skull, which may be useful for improving the contrast-to-tissue ratio or imaging resolution, respectively. Preliminary in vivo experiments demonstrated the system's ability to induce blood-brain barrier opening and simultaneously spatially map microbubble cavitation activity in a rat model. This work presents a tool to investigate optimal strategies for non

  14. Surface density mapping of natural tissue by a scanning haptic microscope (SHM).

    Science.gov (United States)

    Moriwaki, Takeshi; Oie, Tomonori; Takamizawa, Keiichi; Murayama, Yoshinobu; Fukuda, Toru; Omata, Sadao; Nakayama, Yasuhide

    2013-02-01

    To expand the performance capacity of the scanning haptic microscope (SHM) beyond surface mapping microscopy of elastic modulus or topography, surface density mapping of a natural tissue was performed by applying a measurement theory of SHM, in which a frequency change occurs upon contact of the sample surface with the SHM sensor - a microtactile sensor (MTS) that vibrates at a pre-determined constant oscillation frequency. This change was mainly stiffness-dependent at a low oscillation frequency and density-dependent at a high oscillation frequency. Two paragon examples with extremely different densities but similar macroscopic elastic moduli in the range of natural soft tissues were selected: one was agar hydrogels and the other silicon organogels with extremely low (less than 25 mg/cm(3)) and high densities (ca. 1300 mg/cm(3)), respectively. Measurements were performed in saline solution near the second-order resonance frequency, which led to the elastic modulus, and near the third-order resonance frequency. There was little difference in the frequency changes between the two resonance frequencies in agar gels. In contrast, in silicone gels, a large frequency change by MTS contact was observed near the third-order resonance frequency, indicating that the frequency change near the third-order resonance frequency reflected changes in both density and elastic modulus. Therefore, a density image of the canine aortic wall was subsequently obtained by subtracting the image observed near the second-order resonance frequency from that near the third-order resonance frequency. The elastin-rich region had a higher density than the collagen-rich region.

  15. Pressure map technology for pressure ulcer patients: can we handle the truth?

    Science.gov (United States)

    Pompeo, Matthew Q

    2013-02-01

    Objective. The purpose of this study was to trial new pressure mapping technology for patients with pressure ulcers. Pressure mapping data was recorded during 3 phases of technology implementation, as nurses became increasingly familiar with pressuremapping technology in a 55-bed, long-term acute care (LTAC) facility in North Texas. Forty-three patients with pressure ulcers were selected for the study. Patients with pressure ulcers, or who were considered at high risk for developing pressure ulcers based on a Braden score of ≤ 12, were selected to utilize a pressure-sensing device system. Turning timeliness improved greatly from the baseline phase to the last phase. The average turning after the 2-hour alarm decreased from 120 minutes to 44 minutes, and the median time to turning decreased from 39 minutes to 17 minutes. If time past 2 hours is considered the most damaging time to tissue, these reductions (average and median) represented 63% and 56% less potential tissue damage. Pressure mapping technology is in its infancy and this paper discusses implications for the future, including barriers to implementation and potential advanced applications. While only changes in nursing practice were measured in this study, the changes observed suggest the technology can be instrumental in reducing hospital-acquired pressure ulcers and improving the healing of pressure wounds in the future. .

  16. Phase retrieval for X-ray in-line phase contrast imaging

    International Nuclear Information System (INIS)

    Scattarella, F.; Bellotti, R.; Tangaro, S.; Gargano, G.; Giannini, C.

    2011-01-01

    A review article about phase retrieval problem in X-ray phase contrast imaging is presented. A simple theoretical framework of Fresnel diffraction imaging by X-rays is introduced. A review of the most important methods for phase retrieval in free-propagation-based X-ray imaging and a new method developed by our collaboration are shown. The proposed algorithm, Combined Mixed Approach (CMA) is based on a mixed transfer function and transport of intensity approach, and it requires at most an initial approximate estimate of the average phase shift introduced by the object as prior knowledge. The accuracy with which this initial estimate is known determines the convenience speed of algorithm. The new proposed algorithm is based on the retrieval of both the object phase and its complex conjugate. The results obtained by the algorithm on simulated data have shown that the obtained reconstructed phase maps are characterized by particularly low normalized mean square errors. The algorithm was also tested on noisy experimental phase contrast data, showing a good efficiency in recovering phase information and enhancing the visibility of details inside soft tissues.

  17. In-Field, In Situ, and In Vivo 3-Dimensional Elemental Mapping for Plant Tissue and Soil Analysis Using Laser-Induced Breakdown Spectroscopy

    Directory of Open Access Journals (Sweden)

    Chunjiang Zhao

    2016-10-01

    Full Text Available Sensing and mapping element distributions in plant tissues and its growth environment has great significance for understanding the uptake, transport, and accumulation of nutrients and harmful elements in plants, as well as for understanding interactions between plants and the environment. In this study, we developed a 3-dimensional elemental mapping system based on laser-induced breakdown spectroscopy that can be deployed in- field to directly measure the distribution of multiple elements in living plants as well as in the soil. Mapping is performed by a fast scanning laser, which ablates a micro volume of a sample to form a plasma. The presence and concentration of specific elements are calculated using the atomic, ionic, and molecular spectral characteristics of the plasma emission spectra. Furthermore, we mapped the pesticide residues in maize leaves after spraying to demonstrate the capacity of this method for trace elemental mapping. We also used the system to quantitatively detect the element concentrations in soil, which can be used to further understand the element transport between plants and soil. We demonstrate that this method has great potential for elemental mapping in plant tissues and soil with the advantages of 3-dimensional and multi-elemental mapping, in situ and in vivo measurement, flexible use, and low cost.

  18. FPGA implementation of self organizing map with digital phase locked loops.

    Science.gov (United States)

    Hikawa, Hiroomi

    2005-01-01

    The self-organizing map (SOM) has found applicability in a wide range of application areas. Recently new SOM hardware with phase modulated pulse signal and digital phase-locked loops (DPLLs) has been proposed (Hikawa, 2005). The system uses the DPLL as a computing element since the operation of the DPLL is very similar to that of SOM's computation. The system also uses square waveform phase to hold the value of the each input vector element. This paper discuss the hardware implementation of the DPLL SOM architecture. For effective hardware implementation, some components are redesigned to reduce the circuit size. The proposed SOM architecture is described in VHDL and implemented on field programmable gate array (FPGA). Its feasibility is verified by experiments. Results show that the proposed SOM implemented on the FPGA has a good quantization capability, and its circuit size very small.

  19. Osteosarcoma: correlation of T1 map and histology map

    International Nuclear Information System (INIS)

    Suh, Jin Suck; Yun, Mi Jin; Jeong, Eun Kee; Shin, Kyoo Ho; Yang, Woo Ick

    1999-01-01

    To determine whether T1 mapping shows regional differences between viable and necrotic regions of osteosarcomas after anticancer chemotherapy and to assess whether this mapping is able to express the characteristics of various intramural tissue components. Eleven of 20 osteosarcomas were included in this study, while the remaining nine were excluded because the tumor site was inappropriate for comparison of T1 map and tumor macrosection. All patients underwent MR imaging for the purpose of T1 mapping, followed by pre-operative chemotherapy and subsequent limb-salvage surgery. Spin echo pulse sequencing was used with varying TR (100, 200, 400, 800, 1600, and 2400 msec) and a constant TE of 20 msec. Using a C-language software program, T1 relaxation time was calculated on a pixel-by-pixel basis and then a T1 map was generated by using a post-processing program, NIH Image. We attempted correlation of the T1 map and histologic findings, particularly in regions of interest(ROI) if certain areas were different from other regions on either the T1 or histologic map. Value was expressed as an average of the ratio of T1 of ROI and T1 of fat tissue, and this was used as an internal reference for normalization of the measurement. Tumor necrosis was 100 %(Grade IV) in six specimens, and over 90 % (Grade III) in five. Viable tumor cells were found mostly in regions with chondroid matrix and seldom in regions with osteoid matrix. Regardless of cell viability, values ranged from 0.9 to 9.87(mean, 4.02) in tumor necrotic area with osteoid matrices, and from 3.04 to 3.9(mean, 3.55) in areas with chondroid matrices. Other regions with fibrous tissue proliferation, hemorrhage, and fatty necrosis showed values of 2.92-9.83(mean, 7.20), 2.65-5.96(mean,3.59), and 1.43-3.11(mean, 2.68) respectively. The values of various tissues overlapped. No statistically significant difference was found between regions in which tumors were viable and those with tumor necrosis. Although we hypothesized

  20. Magneto-motive detection of tissue-based macrophages by differential phase optical coherence tomography.

    Science.gov (United States)

    Oh, Junghwan; Feldman, Marc D; Kim, Jihoon; Kang, Hyun Wook; Sanghi, Pramod; Milner, Thomas E

    2007-03-01

    A novel method to detect tissue-based macrophages using a combination of superparamagnetic iron oxide (SPIO) nanoparticles and differential phase optical coherence tomography (DP-OCT) with an external oscillating magnetic field is reported. Magnetic force acting on iron-laden tissue-based macrophages was varied by applying a sinusoidal current to a solenoid containing a conical iron core that substantially focused and increased magnetic flux density. Nanoparticle motion was detected with DP-OCT, which can detect tissue movement with nanometer resolution. Frequency response of iron-laden tissue movement was twice the modulation frequency since the magnetic force is proportional to the product of magnetic flux density and gradient. Results of our experiments indicate that DP-OCT can be used to identify tissue-based macrophage when excited by an external focused oscillating magnetic field. (c) 2007 Wiley-Liss, Inc

  1. [Determination of acyclovir in mouse plasma and tissues by reversed-phase high performance liquid chromatography].

    Science.gov (United States)

    Xu, Y; Zhou, S W; Tang, J L; Huang, L Q

    2001-11-01

    The aim of this study was to establish an high performance liquid chromatographic method for determining acyclovir (ACV) concentration in mouse plasma and tissues. A solution of 0.25 mL 60 g/L perchloric acid and 0.25 mL acetonitrile was added into 0.2 mL plasma or 0.2 g tissues to precipitate proteins. Following centrifugation, the supernatant obtained was injected into a reversed-phase column. Operating conditions were Hypersil ODS column(250 mm x 4.6 mm i.d., 5 microns), methanol-water-acetic acid(1:99:0.5, volume ratio) solution as mobile phase at a flow rate of 1.5 mL/min, UV detection at 252 nm. The detection limit of ACV concentration in plasma was 20 micrograms/L and that in tissues was 50 ng/g. The standard curves for ACV were linear in plasma and homogenate of tissues (r > 0.99). The precision of the method was good and the recoveries of ACV were higher than 97.5%. So this method is rapid, accurate and convenient for determination of ACV concentrations in plasma and tissues.

  2. Spatial-area selective retrieval of multiple object-place associations in a hierarchical cognitive map formed by theta phase coding.

    Science.gov (United States)

    Sato, Naoyuki; Yamaguchi, Yoko

    2009-06-01

    The human cognitive map is known to be hierarchically organized consisting of a set of perceptually clustered landmarks. Patient studies have demonstrated that these cognitive maps are maintained by the hippocampus, while the neural dynamics are still poorly understood. The authors have shown that the neural dynamic "theta phase precession" observed in the rodent hippocampus may be capable of forming hierarchical cognitive maps in humans. In the model, a visual input sequence consisting of object and scene features in the central and peripheral visual fields, respectively, results in the formation of a hierarchical cognitive map for object-place associations. Surprisingly, it is possible for such a complex memory structure to be formed in a few seconds. In this paper, we evaluate the memory retrieval of object-place associations in the hierarchical network formed by theta phase precession. The results show that multiple object-place associations can be retrieved with the initial cue of a scene input. Importantly, according to the wide-to-narrow unidirectional connections among scene units, the spatial area for object-place retrieval can be controlled by the spatial area of the initial cue input. These results indicate that the hierarchical cognitive maps have computational advantages on a spatial-area selective retrieval of multiple object-place associations. Theta phase precession dynamics is suggested as a fundamental neural mechanism of the human cognitive map.

  3. Combined passive acoustic mapping and magnetic resonance thermometry for monitoring phase-shift nanoemulsion enhanced focused ultrasound therapy

    Science.gov (United States)

    Crake, Calum; Meral, F. Can; Burgess, Mark T.; Papademetriou, Iason T.; McDannold, Nathan J.; Porter, Tyrone M.

    2017-08-01

    Focused ultrasound (FUS) has the potential to enable precise, image-guided noninvasive surgery for the treatment of cancer in which tumors are identified and destroyed in a single integrated procedure. However, success of the method in highly vascular organs has been limited due to heat losses to perfusion, requiring development of techniques to locally enhance energy absorption and heating. In addition, FUS procedures are conventionally monitored using MRI, which provides excellent anatomical images and can map temperature, but is not capable of capturing the full gamut of available data such as the acoustic emissions generated during this inherently acoustically-driven procedure. Here, we employed phase-shift nanoemulsions (PSNE) embedded in tissue phantoms to promote cavitation and hence temperature rise induced by FUS. In addition, we incorporated passive acoustic mapping (PAM) alongside simultaneous MR thermometry in order to visualize both acoustic emissions and temperature rise, within the bore of a full scale clinical MRI scanner. Focal cavitation of PSNE could be resolved using PAM and resulted in accelerated heating and increased the maximum elevated temperature measured via MR thermometry compared to experiments without nanoemulsions. Over time, the simultaneously acquired acoustic and temperature maps show translation of the focus of activity towards the FUS transducer, and the magnitude of the increase in cavitation and focal shift both increased with nanoemulsion concentration. PAM results were well correlated with MRI thermometry and demonstrated greater sensitivity, with the ability to detect cavitation before enhanced heating was observed. The results suggest that PSNE could be beneficial for enhancement of thermal focused ultrasound therapies and that PAM could be a critical tool for monitoring this process.

  4. Exatecan in pretreated adult patients with advanced soft tissue sarcoma: results of a phase II--study of the EORTC Soft Tissue and Bone Sarcoma Group

    DEFF Research Database (Denmark)

    Reichardt, P; Nielsen, Ole Steen; Bauer, S

    2007-01-01

    No standard treatment is established for patients with advanced soft tissue sarcoma after previous chemotherapy with anthracyclines and ifosfamide, given either in combination or sequentially. Exatecan (DX-8951f) is a totally synthetic analogue of the topoisomerase I-inhibitor camptothecin, which...... was synthesised to impart increased aqueous solubility, greater tumour efficacy, and less toxicity than camptothecin itself, topotecan or irinotecan. Since some activity against soft tissue sarcomas, especially leiomyosarcomas, has been reported for topoisomerase I-inhibitors, a study with a new and more potent...... agent seemed justified. We report on a prospective multicentre phase II study of Exatecan in adult soft tissue sarcomas failing 1 or 2 lines of chemotherapy in advanced phase, performed within the STBSG of EORTC. Thirty-nine patients (16 leiomyosarcomas and 23 other histologies) were included in two...

  5. Parametric methods for characterizing myocardial tissue by magnetic resonance imaging (part 2): T2 mapping.

    Science.gov (United States)

    Perea Palazón, R J; Solé Arqués, M; Prat González, S; de Caralt Robira, T M; Cibeira López, M T; Ortiz Pérez, J T

    2015-01-01

    Cardiac magnetic resonance imaging is considered the reference technique for characterizing myocardial tissue; for example, T2-weighted sequences make it possible to evaluate areas of edema or myocardial inflammation. However, traditional sequences have many limitations and provide only qualitative information. Moreover, traditional sequences depend on the reference to remote myocardium or skeletal muscle, which limits their ability to detect and quantify diffuse myocardial damage. Recently developed magnetic resonance myocardial mapping techniques enable quantitative assessment of parameters indicative of edema. These techniques have proven better than traditional sequences both in acute cardiomyopathy and in acute ischemic heart disease. This article synthesizes current developments in T2 mapping as well as their clinical applications and limitations. Copyright © 2014 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

  6. On network coding and modulation mapping for three-phase bidirectional relaying

    KAUST Repository

    Chang, Ronald Y.; Lin, Sian Jheng; Chung, Wei-Ho

    2015-01-01

    © 2015 IEEE. In this paper, we consider the network coding (NC) enabled three-phase protocol for information exchange between two users in a wireless two-way (bidirectional) relay network. Modulo-based (nonbinary) and XOR-based (binary) NC schemes are considered as information mixture schemes at the relay while all transmissions adopt pulse amplitude modulation (PAM). We first obtain the optimal constellation mapping at the relay that maximizes the decoding performance at the users for each NC scheme. Then, we compare the two NC schemes, each in conjunction with the optimal constellation mapping at the relay, in different conditions. Our results demonstrate that, in the low SNR regime, binary NC outperforms nonbinary NC with 4-PAM, while they have mixed performance with 8-PAM. This observation applies to quadrature amplitude modulation (QAM) composed of two parallel PAMs.

  7. On network coding and modulation mapping for three-phase bidirectional relaying

    KAUST Repository

    Chang, Ronald Y.

    2015-12-03

    © 2015 IEEE. In this paper, we consider the network coding (NC) enabled three-phase protocol for information exchange between two users in a wireless two-way (bidirectional) relay network. Modulo-based (nonbinary) and XOR-based (binary) NC schemes are considered as information mixture schemes at the relay while all transmissions adopt pulse amplitude modulation (PAM). We first obtain the optimal constellation mapping at the relay that maximizes the decoding performance at the users for each NC scheme. Then, we compare the two NC schemes, each in conjunction with the optimal constellation mapping at the relay, in different conditions. Our results demonstrate that, in the low SNR regime, binary NC outperforms nonbinary NC with 4-PAM, while they have mixed performance with 8-PAM. This observation applies to quadrature amplitude modulation (QAM) composed of two parallel PAMs.

  8. Does the fluence map editing in electronic tissue compensator improve dose homogeneity in bilateral field plan of head and neck patients?

    Directory of Open Access Journals (Sweden)

    Kinhikar Rajesh

    2008-01-01

    Full Text Available The purpose of this study was to evaluate the effect of fluence map editing in electronic tissue compensator (ETC on the dose homogeneity for head and neck cancer patients. Treatment planning using 6-MV X-rays and bilateral field arrangement employing ETC was carried out on the computed tomography (CT datasets of 20 patients with head and neck cancer. All the patients were planned in Varian Eclipse three-dimensional treatment planning system (3DTPS with dynamic multileaf collimator (DMLC. The treatment plans, with and without fluence editing, was compared and the effect of pre-editing and post-editing the fluence maps in the treatment field was evaluated. The skin dose was measured with thermoluminescent dosimeters (TLDs and was compared with the skin dose estimated by TPS. The mean percentage volume of the tissue receiving at least 107% of the prescription dose was 5.4 (range 1.5-10; SD 2.4. Post-editing fluence map showed that the mean percentage volume of the tissue receiving at least 107% of the prescription dose was 0.47 (range 0.1-0.9; SD 0.3. The mean skin dose measured with TLD was found to be 74% (range 71-80% of the prescribed dose while the TPS showed the mean skin dose as 85% (range 80-90%. The TPS overestimated the skin dose by 11%. Fluence map editing thus proved to be a potential tool for improving dose homogeneity in head and neck cancer patients planned with ETC, thus reducing the hot spots in the treatment region as well. The treatment with ETC is feasible with DMLC and does not take any additional time for setup or delivery. The method used to edit the fluence maps is simple and time efficient. Manual control over a plan is essential to create the best treatment plan possible.

  9. Cardiac functional mapping for thallium-201 myocardial perfusion, washout, wall motion and phase using single-photon emission computed tomography (SPECT)

    International Nuclear Information System (INIS)

    Nakajima, Kenichi; Bunko, Hisashi; Taniguchi, Mitsuru; Taki, Junichi; Tonami, Norihisa; Hisada, Kinichi; Hirano, Takako; Wani, Hidenobu.

    1986-01-01

    A method for three-dimensional functional mapping of Tl-201 myocardial uptake, washout, wall motion and phase was developed using SPECT. Each parameter was mapped using polar display in the same format. Normal values were determined in Tl-201 exercise study in 16 patients. Myocardial counts were lower in the septum and inferior wall and the difference of counts between anterior and inferior walls were greater in man compared with the perfusion pattern in woman. Washout was slower at septum and inferior wall in man, and slightly slower at inferior wall in woman. In gated blood-pool tomography, length-based and count-based Fourier analyses were applied to calculate the parameters of contraction and phase. The results of both Fourier analyses generally agreed; however, the area of abnormality was slightly different. Phase maps were useful for the assessment of asynergy as well as in patients with conduction disorders. These cardiac functional maps using SPECT were considered to be effective for the understanding of three-dimensional informations of cardiac function. (author)

  10. Applications of condensed matter understanding to medical tissues and disease progression: Elemental analysis and structural integrity of tissue scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, D.A., E-mail: d.a.bradley@surrey.ac.u [Centre for Nuclear and Radiation Physics, Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Farquharson, M.J. [Department of Radiography, School of Community and Health Sciences, City University, London (United Kingdom); Gundogdu, O. [Centre for Nuclear and Radiation Physics, Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Al-Ebraheem, Alia [Department of Radiography, School of Community and Health Sciences, City University, London (United Kingdom); Che Ismail, Elna [Centre for Nuclear and Radiation Physics, Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Kaabar, W., E-mail: w.kaabar@surrey.ac.u [Centre for Nuclear and Radiation Physics, Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Bunk, O. [Paul Scherrer Institute, CH-5232 Villigen (Switzerland); Pfeiffer, F. [Paul Scherrer Institute, CH-5232 Villigen (Switzerland); Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Falkenberg, G. [Hamburger Synchrotronstrahlungslabor HASYLAB at Deutsches Elektronensynchrotron DESY, Notkestr. 85, D-22603 Hamburg (Germany); Bailey, M. [Surrey Ion Beam Centre, Advanced Technology Institute, University of Surrey, Guildford GU2 7XH (United Kingdom)

    2010-02-15

    The investigations reported herein link tissue structure and elemental presence with issues of environmental health and disease, exemplified by uptake and storage of potentially toxic elements in the body, the osteoarthritic condition and malignancy in the breast and other soft tissues. Focus is placed on application of state-of-the-art ionizing radiation techniques, including, micro-synchrotron X-ray fluorescence (mu-SXRF) and particle-induced X-ray emission/Rutherford backscattering mapping (mu-PIXE/RBS), coherent small-angle X-ray scattering (cSAXS) and X-ray phase-contrast imaging, providing information on elemental make-up, the large-scale organisation of collagen and anatomical features of moderate and low atomic number media. For the particular situations under investigation, use of such facilities is allowing information to be obtained at an unprecedented level of detail, yielding new understanding of the affected tissues and the progression of disease.

  11. Applications of condensed matter understanding to medical tissues and disease progression: Elemental analysis and structural integrity of tissue scaffolds

    International Nuclear Information System (INIS)

    Bradley, D.A.; Farquharson, M.J.; Gundogdu, O.; Al-Ebraheem, Alia; Che Ismail, Elna; Kaabar, W.; Bunk, O.; Pfeiffer, F.; Falkenberg, G.; Bailey, M.

    2010-01-01

    The investigations reported herein link tissue structure and elemental presence with issues of environmental health and disease, exemplified by uptake and storage of potentially toxic elements in the body, the osteoarthritic condition and malignancy in the breast and other soft tissues. Focus is placed on application of state-of-the-art ionizing radiation techniques, including, micro-synchrotron X-ray fluorescence (μ-SXRF) and particle-induced X-ray emission/Rutherford backscattering mapping (μ-PIXE/RBS), coherent small-angle X-ray scattering (cSAXS) and X-ray phase-contrast imaging, providing information on elemental make-up, the large-scale organisation of collagen and anatomical features of moderate and low atomic number media. For the particular situations under investigation, use of such facilities is allowing information to be obtained at an unprecedented level of detail, yielding new understanding of the affected tissues and the progression of disease.

  12. Vaccination with map specific peptides reduces map burden in tissues of infected goats

    DEFF Research Database (Denmark)

    Melvang, Heidi Mikkelsen; Hassan, Sufia Butt; Thakur, Aneesh

    As an alternative to protein-based vaccines, we investigated the effect of post-exposure vaccination with Map specific peptides in a goat model aiming at developing a Map vaccine that will neither interfere with diagnosis of paratuberculosis nor bovine tuberculosis. Peptides were initially select...... in the unvaccinated control group seroconverted in ID Screen® ELISA at last sampling prior to euthanasia. These results indicate that a subunit vaccine against Map can induce a protective immune response against paratuberculosis in goats....

  13. Linkage mapping of putative regulator genes of barley grain development characterized by expression profiling

    Directory of Open Access Journals (Sweden)

    Wobus Ulrich

    2009-01-01

    Full Text Available Abstract Background Barley (Hordeum vulgare L. seed development is a highly regulated process with fine-tuned interaction of various tissues controlling distinct physiological events during prestorage, storage and dessication phase. As potential regulators involved within this process we studied 172 transcription factors and 204 kinases for their expression behaviour and anchored a subset of them to the barley linkage map to promote marker-assisted studies on barley grains. Results By a hierachical clustering of the expression profiles of 376 potential regulatory genes expressed in 37 different tissues, we found 50 regulators preferentially expressed in one of the three grain tissue fractions pericarp, endosperm and embryo during seed development. In addition, 27 regulators found to be expressed during both seed development and germination and 32 additional regulators are characteristically expressed in multiple tissues undergoing cell differentiation events during barley plant ontogeny. Another 96 regulators were, beside in the developing seed, ubiquitously expressed among all tissues of germinating seedlings as well as in reproductive tissues. SNP-marker development for those regulators resulted in anchoring 61 markers on the genetic linkage map of barley and the chromosomal assignment of another 12 loci by using wheat-barley addition lines. The SNP frequency ranged from 0.5 to 1.0 SNP/kb in the parents of the various mapping populations and was 2.3 SNP/kb over all eight lines tested. Exploration of macrosynteny to rice revealed that the chromosomal orders of the mapped putative regulatory factors were predominantly conserved during evolution. Conclusion We identified expression patterns of major transcription factors and signaling related genes expressed during barley ontogeny and further assigned possible functions based on likely orthologs functionally well characterized in model plant species. The combined linkage map and reference

  14. Robust and flexible mapping for real-time distributed applications during the early design phases

    DEFF Research Database (Denmark)

    Gan, Junhe; Pop, Paul; Gruian, Flavius

    2012-01-01

    has a high chance of being schedulable, considering the wcet uncertainties, whereas a flexible mapping has a high chance to successfully accommodate the future scenarios. We propose a Genetic Algorithm-based approach to solve this optimization problem. Extensive experiments show the importance......We are interested in mapping hard real-time applications on distributed heterogeneous architectures. An application is modeled as a set of tasks, and we consider a fixed-priority preemptive scheduling policy. We target the early design phases, when decisions have a high impact on the subsequent...... in the functionality requirements are captured using “future scenarios”, which are task sets that model functionality likely to be added in the future. In this context, we derive a mapping of tasks in the application, such that the resulted implementation is both robust and flexible. Robust means that the application...

  15. Suitable reference tissues for quantitative susceptibility mapping of the brain.

    Science.gov (United States)

    Straub, Sina; Schneider, Till M; Emmerich, Julian; Freitag, Martin T; Ziener, Christian H; Schlemmer, Heinz-Peter; Ladd, Mark E; Laun, Frederik B

    2017-07-01

    Since quantitative susceptibility mapping (QSM) quantifies magnetic susceptibility relative to a reference value, a suitable reference tissue has to be available to compare different subjects and stages of disease. To find such a suitable reference tissue for QSM of the brain, melanoma patients with and without brain metastases were measured. Twelve reference regions were chosen and assessed for stability of susceptibility values with respect to multiple intra-individual and inter-individual measurements, age, and stage of disease. Cerebrospinal fluid (CSF), the internal capsule and one region in the splenium of the corpus callosum are the regions with the smallest standard deviations of the mean susceptibility value. The mean susceptibility is 0.010 ± 0.014 ppm for CSF in the atrium of the lateral ventricles (csf post ), -0.060 ± 0.019 ppm for the posterior limb of the internal capsule (ci2), and -0.008 ± 0.019 ppm for the splenium of the corpus callosum. csf post and ci2 show nearly no dependence on age or stage of disease, whereas some other regions, e.g., the red nucleus, show moderate dependence on age or disease. The internal capsule and CSF appear to be the most suitable reference regions for QSM of the brain in the melanoma patients studied. Both showed virtually no dependence on age or disease and small variations among patients. Magn Reson Med 78:204-214, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  16. Impact of GPS antenna phase center and code residual variation maps on orbit and baseline determination of GRACE

    Science.gov (United States)

    Mao, X.; Visser, P. N. A. M.; van den IJssel, J.

    2017-06-01

    Precision Orbit Determination (POD) is a prerequisite for the success of many Low Earth Orbiting (LEO) satellite missions. With high-quality, dual-frequency Global Positioning System (GPS) receivers, typically precisions of the order of a few cm are possible for single-satellite POD, and of a few mm for relative POD of formation flying spacecraft with baselines up to hundreds of km. To achieve the best precision, the use of Phase Center Variation (PCV) maps is indispensable. For LEO GPS receivers, often a-priori PCV maps are obtained by a pre-launch ground campaign, which is not able to represent the real space-borne environment of satellites. Therefore, in-flight calibration of the GPS antenna is more widely conducted. This paper shows that a further improvement is possible by including the so-called Code Residual Variation (CRV) maps in absolute/undifferenced and relative/Double-differenced (DD) POD schemes. Orbit solutions are produced for the GRACE satellite formation for a four months test period (August-November, 2014), demonstrating enhanced orbit precision after first using the in-flight PCV maps and a further improvement after including the CRV maps. The application of antenna maps leads to a better consistency with independent Satellite Laser Ranging (SLR) and K-band Ranging (KBR) low-low Satellite-to-Satellite Tracking (ll-SST) observations. The inclusion of the CRV maps results also in a much better consistency between reduced-dynamic and kinematic orbit solutions for especially the cross-track direction. The improvements are largest for GRACE-B, where a cross-talk between the GPS main antenna and the occultation antenna yields higher systematic observation residuals. For high-precision relative POD which necessitates DD carrier-phase ambiguity fixing, in principle frequency-dependent PCV maps would be required. To this aim, use is made of an Extended Kalman Filter (EKF) that is capable of optimizing relative spacecraft dynamics and iteratively fixing

  17. Post-exposure vaccination with multi-stage vaccine significantly reduce map level in tissues without interference in diagnostics

    DEFF Research Database (Denmark)

    Thakur, Aneesh; Aagaard, Claus; Melvang, Heidi Mikkelsen

    A new (Fet11) vaccine against paratuberculosis based on recombinant antigens from acute and latent stages of Map infection was developed to be used without interference with diagnostic tests for bovine TB and Johne’s disease. Calves were orally inoculated with 2x10E10 live Map in their third week...... of life and randomly assigned to four groups of seven calves each. One group was left unvaccinated, while other calves were post-exposure vaccinated with either a whole-cell vaccine at 16 weeks, or Fet11 vaccine at 3 and 7, or 16 and 20 weeks of age, respectively. Antibody responses were measured by ID...... Screen® ELISA and individual vaccine protein ELISAs along with FACS and IFN-γ responses to PPDj and to individual vaccine proteins. At termination 8 or 12 months of age, Map burden in a number of gut tissues was determined by quantitative IS900 PCR and histopathology. Fet11 vaccination of calves at 16...

  18. Parametric techniques for characterizing myocardial tissue by magnetic resonance imaging (part 1): T1 mapping.

    Science.gov (United States)

    Perea Palazón, R J; Ortiz Pérez, J T; Prat González, S; de Caralt Robira, T M; Cibeira López, M T; Solé Arqués, M

    2016-01-01

    The development of myocardial fibrosis is a common process in the appearance of ventricular dysfunction in many heart diseases. Magnetic resonance imaging makes it possible to accurately evaluate the structure and function of the heart, and its role in the macroscopic characterization of myocardial fibrosis by late enhancement techniques has been widely validated clinically. Recent studies have demonstrated that T1-mapping techniques can quantify diffuse myocardial fibrosis and the expansion of the myocardial extracellular space in absolute terms. However, further studies are necessary to validate the usefulness of this technique in the early detection of tissue remodeling at a time when implementing early treatment would improve a patient's prognosis. This article reviews the state of the art for T1 mapping of the myocardium, its clinical applications, and its limitations. Copyright © 2016 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

  19. MR-guided noninvasive thermal coagulation of in-vivo liver tissue using ultrasonic phased array

    Science.gov (United States)

    Daum, Douglas R.; Smith, Nadine; McDannold, Nathan; Hynynen, Kullervo H.

    1999-05-01

    Magnetic resonance (MR) imaging was used to guide and monitor the thermal tissue coagulation of in vivo porcine tissue using a 256 element ultrasonic phased array. The array could coagulate tissue volumes greater than 2 cm3 in liver and 0.5 cm3 in kidney using a single 20 second sonication. This sonication used multiple focus fields which were temporally cycled to heat large tissue volumes simultaneously. Estimates of the coagulated tissue using a thermal dose threshold compare well with T2-weighted images of post sonication lesions. The overlapping large focal volumes could aid in the treatment of large tumor volumes which require multiple overlapping sonications. The ability of MR to detect the presence and undesirable thermal increases at acoustic obstacle such as cartilaginous and bony ribs is demonstrated. This could have a significant impact on the ability to monitor thermal treatments of the liver and other organs which are acoustically blocked.

  20. Unexpected Relationships and Inbreeding in HapMap Phase III Populations

    Science.gov (United States)

    Stevens, Eric L.; Baugher, Joseph D.; Shirley, Matthew D.; Frelin, Laurence P.; Pevsner, Jonathan

    2012-01-01

    Correct annotation of the genetic relationships between samples is essential for population genomic studies, which could be biased by errors or omissions. To this end, we used identity-by-state (IBS) and identity-by-descent (IBD) methods to assess genetic relatedness of individuals within HapMap phase III data. We analyzed data from 1,397 individuals across 11 ethnic populations. Our results support previous studies (Pemberton et al., 2010; Kyriazopoulou-Panagiotopoulou et al., 2011) assessing unknown relatedness present within this population. Additionally, we present evidence for 1,657 novel pairwise relationships across 9 populations. Surprisingly, significant Cotterman's coefficients of relatedness K1 (IBD1) values were detected between pairs of known parents. Furthermore, significant K2 (IBD2) values were detected in 32 previously annotated parent-child relationships. Consistent with a hypothesis of inbreeding, regions of homozygosity (ROH) were identified in the offspring of related parents, of which a subset overlapped those reported in previous studies (Gibson et al. 2010; Johnson et al. 2011). In total, we inferred 28 inbred individuals with ROH that overlapped areas of relatedness between the parents and/or IBD2 sharing at a different genomic locus between a child and a parent. Finally, 8 previously annotated parent-child relationships had unexpected K0 (IBD0) values (resulting from a chromosomal abnormality or genotype error), and 10 previously annotated second-degree relationships along with 38 other novel pairwise relationships had unexpected IBD2 (indicating two separate paths of recent ancestry). These newly described types of relatedness may impact the outcome of previous studies and should inform the design of future studies relying on the HapMap Phase III resource. PMID:23185369

  1. Raman molecular imaging of brain frozen tissue sections.

    Science.gov (United States)

    Kast, Rachel E; Auner, Gregory W; Rosenblum, Mark L; Mikkelsen, Tom; Yurgelevic, Sally M; Raghunathan, Aditya; Poisson, Laila M; Kalkanis, Steven N

    2014-10-01

    Raman spectroscopy provides a molecular signature of the region being studied. It is ideal for neurosurgical applications because it is non-destructive, label-free, not impacted by water concentration, and can map an entire region of tissue. The objective of this paper is to demonstrate the meaningful spatial molecular information provided by Raman spectroscopy for identification of regions of normal brain, necrosis, diffusely infiltrating glioma and solid glioblastoma (GBM). Five frozen section tissues (1 normal, 1 necrotic, 1 GBM, and 2 infiltrating glioma) were mapped in their entirety using a 300-µm-square step size. Smaller regions of interest were also mapped using a 25-µm step size. The relative concentrations of relevant biomolecules were mapped across all tissues and compared with adjacent hematoxylin and eosin-stained sections, allowing identification of normal, GBM, and necrotic regions. Raman peaks and peak ratios mapped included 1003, 1313, 1431, 1585, and 1659 cm(-1). Tissue maps identified boundaries of grey and white matter, necrosis, GBM, and infiltrating tumor. Complementary information, including relative concentration of lipids, protein, nucleic acid, and hemoglobin, was presented in a manner which can be easily adapted for in vivo tissue mapping. Raman spectroscopy can successfully provide label-free imaging of tissue characteristics with high accuracy. It can be translated to a surgical or laboratory tool for rapid, non-destructive imaging of tumor margins.

  2. Anelasticity maps for acoustic dissipation associated with phase transitions in minerals

    Science.gov (United States)

    Carpenter, Michael A.; Zhang, Zhiying

    2011-07-01

    Acoustic dissipation due to structural phase transitions in minerals could give rise to large seismic attenuation effects superimposed on the high temperature background contribution from dislocations and grain boundaries in the Earth. In addition to the possibility of a sharp peak actually at a transition point for both compressional and shear waves, significant attenuation might arise over wider temperature intervals due to the mobility of transformation twins or other defects associated with the transition. Attenuation due to structural phase transitions in quartz, pyroxenes, perovskites, stishovite and hollandite, or to spin state transitions of Fe2+ in magnesiowüstite and perovskite and the hcp/bcc transition in iron-nickel (Fe-Ni) alloy, are reviewed from this perspective. To these can be added possible loss behaviour associated with reconstructive transitions which might occur by a ledge mechanism on topotactic interfaces (orthopyroxene/clinopyroxene, olivine/spinel and perovskite/postperovskite), with impurities (Snoek effect) or with mobility of protons. There are experimental difficulties associated with measuring dissipation effects in situ at simultaneous high pressures and temperatures, so reliance is currently placed on investigation of analogue phases such as LaCoO3 for spin-state behaviour and LaAlO3 for the dynamics of ferroelastic twin walls. Similarly, it is not possible to measure loss dynamics simultaneously at the low stresses and low frequencies that pertain in seismic waves, so reliance must be placed on combining different techniques, such as dynamic mechanical analysis (low frequency, relatively high stress) and resonant ultrasound spectroscopy (high frequency, low stress), to extrapolate acoustic loss behaviour over wide frequency, temperature and stress intervals. In this context 'anelasticity maps' provide a convenient means of representing different loss mechanisms. Contouring of the inverse mechanical quality factor, Q-1, can be

  3. Monitoring of temperature-mediated phase transitions of adipose tissue by combined optical coherence tomography and Abbe refractometry.

    Science.gov (United States)

    Yanina, Irina Y; Popov, Alexey P; Bykov, Alexander V; Meglinski, Igor V; Tuchin, Valery V

    2018-01-01

    Observation of temperature-mediated phase transitions between lipid components of the adipose tissues has been performed by combined use of the Abbe refractometry and optical coherence tomography. The phase transitions of the lipid components were clearly observed in the range of temperatures from 24°C to 60°C, and assessed by quantitatively monitoring the changes of the refractive index of 1- to 2-mm-thick porcine fat tissue slices. The developed approach has a great potential as an alternative method for obtaining accurate information on the processes occurring during thermal lipolysis. (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

  4. Interfacial orientation and misorientation relationships in nanolamellar Cu/Nb composites using transmission-electron-microscope-based orientation and phase mapping

    International Nuclear Information System (INIS)

    Liu, X.; Nuhfer, N.T.; Rollett, A.D.; Sinha, S.; Lee, S.-B.; Carpenter, J.S.; LeDonne, J.E.; Darbal, A.; Barmak, K.

    2014-01-01

    A transmission-electron-microscope-based orientation mapping technique that makes use of beam precession to achieve near-kinematical conditions was used to map the phase and crystal orientations in nanolamellar Cu/Nb composites with average layer thicknesses of 86, 30 and 18 nm. Maps of high quality and reliability were obtained by comparing the recorded diffraction patterns with pre-calculated templates. Particular care was taken in optimizing the dewarping parameters and in calibrating the frames of reference. Layers with thicknesses as low as 4 nm were successfully mapped. Heterophase interface plane and character distributions (HIPD and HICD, respectively) of Cu and Nb phases from the samples were determined from the orientation maps. In addition, local orientation relation stereograms of the Cu/Nb interfaces were calculated, and these revealed the detailed layer-to-layer texture information. The results are in agreement with previously reported neutron-diffraction-based and precession-electron-diffraction-based measurements on an accumulated roll bonding (ARB)-fabricated Cu/Nb sample with an average layer thickness of 30 nm as well as scanning-electron-microscope-based electron backscattered diffraction HIPD/HICD plots of ARB-fabricated Cu/Nb samples with layer thicknesses between 200 and 600 nm

  5. Combined mixed approach algorithm for in-line phase-contrast x-ray imaging

    International Nuclear Information System (INIS)

    De Caro, Liberato; Scattarella, Francesco; Giannini, Cinzia; Tangaro, Sabina; Rigon, Luigi; Longo, Renata; Bellotti, Roberto

    2010-01-01

    Purpose: In the past decade, phase-contrast imaging (PCI) has been applied to study different kinds of tissues and human body parts, with an increased improvement of the image quality with respect to simple absorption radiography. A technique closely related to PCI is phase-retrieval imaging (PRI). Indeed, PCI is an imaging modality thought to enhance the total contrast of the images through the phase shift introduced by the object (human body part); PRI is a mathematical technique to extract the quantitative phase-shift map from PCI. A new phase-retrieval algorithm for the in-line phase-contrast x-ray imaging is here proposed. Methods: The proposed algorithm is based on a mixed transfer-function and transport-of-intensity approach (MA) and it requires, at most, an initial approximate estimate of the average phase shift introduced by the object as prior knowledge. The accuracy in the initial estimate determines the convergence speed of the algorithm. The proposed algorithm retrieves both the object phase and its complex conjugate in a combined MA (CMA). Results: Although slightly less computationally effective with respect to other mixed-approach algorithms, as two phases have to be retrieved, the results obtained by the CMA on simulated data have shown that the obtained reconstructed phase maps are characterized by particularly low normalized mean square errors. The authors have also tested the CMA on noisy experimental phase-contrast data obtained by a suitable weakly absorbing sample consisting of a grid of submillimetric nylon fibers as well as on a strongly absorbing object made of a 0.03 mm thick lead x-ray resolution star pattern. The CMA has shown a good efficiency in recovering phase information, also in presence of noisy data, characterized by peak-to-peak signal-to-noise ratios down to a few dBs, showing the possibility to enhance with phase radiography the signal-to-noise ratio for features in the submillimetric scale with respect to the attenuation

  6. Label-free tissue scanner for colorectal cancer screening

    Science.gov (United States)

    Kandel, Mikhail E.; Sridharan, Shamira; Liang, Jon; Luo, Zelun; Han, Kevin; Macias, Virgilia; Shah, Anish; Patel, Roshan; Tangella, Krishnarao; Kajdacsy-Balla, Andre; Guzman, Grace; Popescu, Gabriel

    2017-06-01

    The current practice of surgical pathology relies on external contrast agents to reveal tissue architecture, which is then qualitatively examined by a trained pathologist. The diagnosis is based on the comparison with standardized empirical, qualitative assessments of limited objectivity. We propose an approach to pathology based on interferometric imaging of "unstained" biopsies, which provides unique capabilities for quantitative diagnosis and automation. We developed a label-free tissue scanner based on "quantitative phase imaging," which maps out optical path length at each point in the field of view and, thus, yields images that are sensitive to the "nanoscale" tissue architecture. Unlike analysis of stained tissue, which is qualitative in nature and affected by color balance, staining strength and imaging conditions, optical path length measurements are intrinsically quantitative, i.e., images can be compared across different instruments and clinical sites. These critical features allow us to automate the diagnosis process. We paired our interferometric optical system with highly parallelized, dedicated software algorithms for data acquisition, allowing us to image at a throughput comparable to that of commercial tissue scanners while maintaining the nanoscale sensitivity to morphology. Based on the measured phase information, we implemented software tools for autofocusing during imaging, as well as image archiving and data access. To illustrate the potential of our technology for large volume pathology screening, we established an "intrinsic marker" for colorectal disease that detects tissue with dysplasia or colorectal cancer and flags specific areas for further examination, potentially improving the efficiency of existing pathology workflows.

  7. Theory and preliminary experimental verification of quantitative edge illumination x-ray phase contrast tomography.

    Science.gov (United States)

    Hagen, C K; Diemoz, P C; Endrizzi, M; Rigon, L; Dreossi, D; Arfelli, F; Lopez, F C M; Longo, R; Olivo, A

    2014-04-07

    X-ray phase contrast imaging (XPCi) methods are sensitive to phase in addition to attenuation effects and, therefore, can achieve improved image contrast for weakly attenuating materials, such as often encountered in biomedical applications. Several XPCi methods exist, most of which have already been implemented in computed tomographic (CT) modality, thus allowing volumetric imaging. The Edge Illumination (EI) XPCi method had, until now, not been implemented as a CT modality. This article provides indications that quantitative 3D maps of an object's phase and attenuation can be reconstructed from EI XPCi measurements. Moreover, a theory for the reconstruction of combined phase and attenuation maps is presented. Both reconstruction strategies find applications in tissue characterisation and the identification of faint, weakly attenuating details. Experimental results for wires of known materials and for a biological object validate the theory and confirm the superiority of the phase over conventional, attenuation-based image contrast.

  8. Numerically Based Phase Transformation Maps for Dissimilar Aluminum Alloys Joined by Friction Stir-Welding

    Directory of Open Access Journals (Sweden)

    Carter Hamilton

    2018-05-01

    Full Text Available Sheets of aluminum 2017A-T451 and 7075-T651 were friction stir-welded in a butt-weld configuration. An existing computational model of the welding process for temperature distribution and material flow was adapted to estimate the phase transformations that occur across the weld zone. Near the weld center, process temperatures are sufficient to fully dissolve the equilibrium η phase in 7075 and partially dissolve the equilibrium S phase in 2017A. Upon cooling, Guinier–Preston (GP and Guinier–Preston–Bagaryatsky (GPB zones re-precipitate, and hardness recovers. Due to the more complete dissolution of the equilibrium phase in 7075, the hardness recovery skews toward whichever side of the weld, i.e., the advancing or retreating side, represents the 7075 workpiece. Phase transformation maps generated by the numerical simulation align not only with the hardness profiles taken across the weld zone, but also with positron lifetimes obtained through positron annihilation lifetime spectroscopy (PALS. Boundaries between the aluminum matrix and the secondary phases provide open volumes to trap positrons; therefore, positron lifetimes across the weld correspond with the phase transformations that occur in 7075 and 2017A during processing.

  9. Optical coherence tomography detection of shear wave propagation in inhomogeneous tissue equivalent phantoms and ex-vivo carotid artery samples

    Science.gov (United States)

    Razani, Marjan; Luk, Timothy W.H.; Mariampillai, Adrian; Siegler, Peter; Kiehl, Tim-Rasmus; Kolios, Michael C.; Yang, Victor X.D.

    2014-01-01

    In this work, we explored the potential of measuring shear wave propagation using optical coherence elastography (OCE) in an inhomogeneous phantom and carotid artery samples based on a swept-source optical coherence tomography (OCT) system. Shear waves were generated using a piezoelectric transducer transmitting sine-wave bursts of 400 μs duration, applying acoustic radiation force (ARF) to inhomogeneous phantoms and carotid artery samples, synchronized with a swept-source OCT (SS-OCT) imaging system. The phantoms were composed of gelatin and titanium dioxide whereas the carotid artery samples were embedded in gel. Differential OCT phase maps, measured with and without the ARF, detected the microscopic displacement generated by shear wave propagation in these phantoms and samples of different stiffness. We present the technique for calculating tissue mechanical properties by propagating shear waves in inhomogeneous tissue equivalent phantoms and carotid artery samples using the ARF of an ultrasound transducer, and measuring the shear wave speed and its associated properties in the different layers with OCT phase maps. This method lays the foundation for future in-vitro and in-vivo studies of mechanical property measurements of biological tissues such as vascular tissues, where normal and pathological structures may exhibit significant contrast in the shear modulus. PMID:24688822

  10. Oxygen Mapping within Healthy and Acutely Infarcted Brain Tissue in Humans Using the NMR Relaxation of Lipids: A Proof-Of-Concept Translational Study.

    Science.gov (United States)

    Colliez, Florence; Safronova, Marta M; Magat, Julie; Joudiou, Nicolas; Peeters, André P; Jordan, Bénédicte F; Gallez, Bernard; Duprez, Thierry

    2015-01-01

    The clinical applicability of brain oxygenation mapping using the MOBILE (Mapping of Oxygen By Imaging Lipids relaxation Enhancement) magnetic resonance (MR) technique was assessed in the clinical setting of normal brain and of acute cerebral ischemia as a founding proof-of-concept translational study. Changes in the oxygenation level within healthy brain tissue can be detected by analyzing the spin-lattice proton relaxation ('Global T1' combining water and lipid protons) because of the paramagnetic properties of molecular oxygen. It was hypothesized that selective measurement of the relaxation of the lipid protons ('Lipids T1') would result in enhanced sensitivity of pO2 mapping because of higher solubility of oxygen in lipids than in water, and this was demonstrated in pre-clinical models using the MOBILE technique. In the present study, 12 healthy volunteers and eight patients with acute (48-72 hours) brain infarction were examined with the same clinical 3T MR system. Both Lipids R1 (R1 = 1/T1) and Global R1 were significantly different in the infarcted area and the contralateral unaffected brain tissue, with a higher statistical significance for Lipids R1 (median difference: 0.408 s-1; pbrain tissue of stroke patients were not significantly different from the R1 values calculated in the brain tissue of healthy volunteers. The main limitations of the present prototypic version of the MOBILE sequence are the long acquisition time (4 min), hampering robustness of data in uncooperative patients, and a 2 mm slice thickness precluding accurate measurements in small infarcts because of partial volume averaging effects.

  11. Characterization of Mechanical Properties of Tissue Scaffolds by Phase Contrast Imaging and Finite Element Modeling.

    Science.gov (United States)

    Bawolin, Nahshon K; Dolovich, Allan T; Chen, Daniel X B; Zhang, Chris W J

    2015-08-01

    In tissue engineering, the cell and scaffold approach has shown promise as a treatment to regenerate diseased and/or damaged tissue. In this treatment, an artificial construct (scaffold) is seeded with cells, which organize and proliferate into new tissue. The scaffold itself biodegrades with time, leaving behind only newly formed tissue. The degradation qualities of the scaffold are critical during the treatment period, since the change in the mechanical properties of the scaffold with time can influence cell behavior. To observe in time the scaffold's mechanical properties, a straightforward method is to deform the scaffold and then characterize scaffold deflection accordingly. However, experimentally observing the scaffold deflection is challenging. This paper presents a novel study on characterization of mechanical properties of scaffolds by phase contrast imaging and finite element modeling, which specifically includes scaffold fabrication, scaffold imaging, image analysis, and finite elements (FEs) modeling of the scaffold mechanical properties. The innovation of the work rests on the use of in-line phase contrast X-ray imaging at 20 KeV to characterize tissue scaffold deformation caused by ultrasound radiation forces and the use of the Fourier transform to identify movement. Once deformation has been determined experimentally, it is then compared with the predictions given by the forward solution of a finite element model. A consideration of the number of separate loading conditions necessary to uniquely identify the material properties of transversely isotropic and fully orthotropic scaffolds is also presented, along with the use of an FE as a form of regularization.

  12. MO-F-CAMPUS-J-04: Tissue Segmentation-Based MR Electron Density Mapping Method for MR-Only Radiation Treatment Planning of Brain

    Energy Technology Data Exchange (ETDEWEB)

    Yu, H [Sunnybrook Health Sciences Centre, Toronto, Ontario (Canada); Lee, Y [Sunnybrook Odette Cancer Centre, Toronto, Ontario (Canada); Ruschin, M [Odette Cancer Centre, Toronto, ON (Canada); Karam, I [Sunnybrook Odette Cancer Center, Toronto, Ontario (Canada); Sahgal, A [University of Toronto, Toronto, ON (Canada)

    2015-06-15

    Purpose: Automatically derive electron density of tissues using MR images and generate a pseudo-CT for MR-only treatment planning of brain tumours. Methods: 20 stereotactic radiosurgery (SRS) patients’ T1-weighted MR images and CT images were retrospectively acquired. First, a semi-automated tissue segmentation algorithm was developed to differentiate tissues with similar MR intensities and large differences in electron densities. The method started with approximately 12 slices of manually contoured spatial regions containing sinuses and airways, then air, bone, brain, cerebrospinal fluid (CSF) and eyes were automatically segmented using edge detection and anatomical information including location, shape, tissue uniformity and relative intensity distribution. Next, soft tissues - muscle and fat were segmented based on their relative intensity histogram. Finally, intensities of voxels in each segmented tissue were mapped into their electron density range to generate pseudo-CT by linearly fitting their relative intensity histograms. Co-registered CT was used as a ground truth. The bone segmentations of pseudo-CT were compared with those of co-registered CT obtained by using a 300HU threshold. The average distances between voxels on external edges of the skull of pseudo-CT and CT in three axial, coronal and sagittal slices with the largest width of skull were calculated. The mean absolute electron density (in Hounsfield unit) difference of voxels in each segmented tissues was calculated. Results: The average of distances between voxels on external skull from pseudo-CT and CT were 0.6±1.1mm (mean±1SD). The mean absolute electron density differences for bone, brain, CSF, muscle and fat are 78±114 HU, and 21±8 HU, 14±29 HU, 57±37 HU, and 31±63 HU, respectively. Conclusion: The semi-automated MR electron density mapping technique was developed using T1-weighted MR images. The generated pseudo-CT is comparable to that of CT in terms of anatomical position of

  13. Analysis of a human brain transcriptome map

    Directory of Open Access Journals (Sweden)

    Greene Jonathan R

    2002-04-01

    Full Text Available Abstract Background Genome wide transcriptome maps can provide tools to identify candidate genes that are over-expressed or silenced in certain disease tissue and increase our understanding of the structure and organization of the genome. Expressed Sequence Tags (ESTs from the public dbEST and proprietary Incyte LifeSeq databases were used to derive a transcript map in conjunction with the working draft assembly of the human genome sequence. Results Examination of ESTs derived from brain tissues (excluding brain tumor tissues suggests that these genes are distributed on chromosomes in a non-random fashion. Some regions on the genome are dense with brain-enriched genes while some regions lack brain-enriched genes, suggesting a significant correlation between distribution of genes along the chromosome and tissue type. ESTs from brain tumor tissues have also been mapped to the human genome working draft. We reveal that some regions enriched in brain genes show a significant decrease in gene expression in brain tumors, and, conversely that some regions lacking in brain genes show an increased level of gene expression in brain tumors. Conclusions This report demonstrates a novel approach for tissue specific transcriptome mapping using EST-based quantitative assessment.

  14. Combining mechanical foaming and thermally induced phase separation to generate chitosan scaffolds for soft tissue engineering.

    Science.gov (United States)

    Biswas, D P; Tran, P A; Tallon, C; O'Connor, A J

    2017-02-01

    In this paper, a novel foaming methodology consisting of turbulent mixing and thermally induced phase separation (TIPS) was used to generate scaffolds for tissue engineering. Air bubbles were mechanically introduced into a chitosan solution which forms the continuous polymer/liquid phase in the foam created. The air bubbles entrained in the foam act as a template for the macroporous architecture of the final scaffolds. Wet foams were crosslinked via glutaraldehyde and frozen at -20 °C to induce TIPS in order to limit film drainage, bubble coalescence and Ostwald ripening. The effects of production parameters, including mixing speed, surfactant concentration and chitosan concentration, on foaming are explored. Using this method, hydrogel scaffolds were successfully produced with up to 80% porosity, average pore sizes of 120 μm and readily tuneable compressive modulus in the range of 2.6 to 25 kPa relevant to soft tissue engineering applications. These scaffolds supported 3T3 fibroblast cell proliferation and penetration and therefore show significant potential for application in soft tissue engineering.

  15. Vaccination with peptides of Mycobacterium avium subsp. paratuberculosis (MAP) reduces MAP burden of infected goats

    DEFF Research Database (Denmark)

    Melvang, Heidi Mikkelsen; Hassan, Sufia Butt; Thakur, Aneesh

    Mycobacterium avium subsp. paratuberculosis (Map) is the cause of paratuberculosis, a chronic enteritis of ruminants that is widespread worldwide. We investigated the effect of post-exposure vaccination with Map specific peptides in a goat model aiming at developing a Map vaccine that will neither...... unique to Map from selected proteins (n =68). For vaccination, 23 MAP peptides (20 µg each) were selected and formulated with Montanide ISA 61 VG adjuvant. At age three weeks 10 goats were orally inoculated with 4x10E9 live Map and assigned to two groups of 5 goats each: 5 vaccinated (V) at 14 and 18...... weeks post inoculation (PI) and 5 unvaccinated (C). At termination 32 weeks PI, Map burdens in 15 intestinal tissues and lymph nodes were determined by IS900 qPCR. Of the 75 tissue samples from the 5 C goats only 5 samples were IS900 qPCR negative. In contrast, only 9 samples in total from 5 V goats...

  16. Brain Injury Lesion Imaging Using Preconditioned Quantitative Susceptibility Mapping without Skull Stripping.

    Science.gov (United States)

    Soman, S; Liu, Z; Kim, G; Nemec, U; Holdsworth, S J; Main, K; Lee, B; Kolakowsky-Hayner, S; Selim, M; Furst, A J; Massaband, P; Yesavage, J; Adamson, M M; Spincemallie, P; Moseley, M; Wang, Y

    2018-04-01

    Identifying cerebral microhemorrhage burden can aid in the diagnosis and management of traumatic brain injury, stroke, hypertension, and cerebral amyloid angiopathy. MR imaging susceptibility-based methods are more sensitive than CT for detecting cerebral microhemorrhage, but methods other than quantitative susceptibility mapping provide results that vary with field strength and TE, require additional phase maps to distinguish blood from calcification, and depict cerebral microhemorrhages as bloom artifacts. Quantitative susceptibility mapping provides universal quantification of tissue magnetic property without these constraints but traditionally requires a mask generated by skull-stripping, which can pose challenges at tissue interphases. We evaluated the preconditioned quantitative susceptibility mapping MR imaging method, which does not require skull-stripping, for improved depiction of brain parenchyma and pathology. Fifty-six subjects underwent brain MR imaging with a 3D multiecho gradient recalled echo acquisition. Mask-based quantitative susceptibility mapping images were created using a commonly used mask-based quantitative susceptibility mapping method, and preconditioned quantitative susceptibility images were made using precondition-based total field inversion. All images were reviewed by a neuroradiologist and a radiology resident. Ten subjects (18%), all with traumatic brain injury, demonstrated blood products on 3D gradient recalled echo imaging. All lesions were visible on preconditioned quantitative susceptibility mapping, while 6 were not visible on mask-based quantitative susceptibility mapping. Thirty-one subjects (55%) demonstrated brain parenchyma and/or lesions that were visible on preconditioned quantitative susceptibility mapping but not on mask-based quantitative susceptibility mapping. Six subjects (11%) demonstrated pons artifacts on preconditioned quantitative susceptibility mapping and mask-based quantitative susceptibility mapping

  17. MAP3K8 (TPL2/COT) Affects Obesity-Induced Adipose Tissue Inflammation without Systemic Effects in Humans and in Mice

    NARCIS (Netherlands)

    Ballak, D.B.; Essen, P. van; Diepen, J.A. van; Jansen, H.J.; Hijmans, A.G.; Matsuguchi, T.; Sparrer, H.; Tack, C.J.J.; Netea, M.G.; Joosten, L.A.B.; Stienstra, R.

    2014-01-01

    Chronic low-grade inflammation in adipose tissue often accompanies obesity, leading to insulin resistance and increasing the risk for metabolic diseases. MAP3K8 (TPL2/COT) is an important signal transductor and activator of pro-inflammatory pathways that has been linked to obesity-induced adipose

  18. Phase transformations in a human tooth tissue at the initial stage of caries.

    Directory of Open Access Journals (Sweden)

    Pavel Seredin

    Full Text Available The aim of the paper is to study phase transformations in solid tissues of the human teeth during the development of fissure caries by Raman and fluorescence microspectroscopy. The study of the areas with fissure caries confirmed the assumption of the formation of a weak interaction between phosphate apatite enamel and organic acids (products of microorganisms. The experimental results obtained with by Raman microspectroscopy showed the formation of dicalcium phosphate dihydrate - CaHPO4-2H2O in the area of mural demineralization of carious fissure. A comparative analysis of structural and spectroscopic data for the intact and carious enamel shows that emergence of a more soluble phase - carbonate-substituted hydroxyapatite - is typical for the initial stage of caries. It is shown that microareas of dental hard tissues in the carious fissure due to an emerging misorientation of apatite crystals have a higher fluorescence yield than the area of the intact enamel. These areas can be easily detected even prior to a deep demineralization (white spot stage for the case of irreversibly changed organomineral complex and intensive removal of the mineral component.

  19. Phase Transformations in a Human Tooth Tissue at the Initial Stage of Caries

    Science.gov (United States)

    Prutskij, Tatiana; Ippolitov, Yury

    2015-01-01

    The aim of the paper is to study phase transformations in solid tissues of the human teeth during the development of fissure caries by Raman and fluorescence microspectroscopy. The study of the areas with fissure caries confirmed the assumption of the formation of a weak interaction between phosphate apatite enamel and organic acids (products of microorganisms). The experimental results obtained with by Raman microspectroscopy showed the formation of dicalcium phosphate dihydrate - CaHPO4-2H2O in the area of mural demineralization of carious fissure. A comparative analysis of structural and spectroscopic data for the intact and carious enamel shows that emergence of a more soluble phase - carbonate-substituted hydroxyapatite - is typical for the initial stage of caries. It is shown that microareas of dental hard tissues in the carious fissure due to an emerging misorientation of apatite crystals have a higher fluorescence yield than the area of the intact enamel. These areas can be easily detected even prior to a deep demineralization (white spot stage) for the case of irreversibly changed organomineral complex and intensive removal of the mineral component. PMID:25901743

  20. In situ biological dose mapping estimates the radiation burden delivered to 'spared' tissue between synchrotron X-ray microbeam radiotherapy tracks.

    Directory of Open Access Journals (Sweden)

    Kai Rothkamm

    Full Text Available Microbeam radiation therapy (MRT using high doses of synchrotron X-rays can destroy tumours in animal models whilst causing little damage to normal tissues. Determining the spatial distribution of radiation doses delivered during MRT at a microscopic scale is a major challenge. Film and semiconductor dosimetry as well as Monte Carlo methods struggle to provide accurate estimates of dose profiles and peak-to-valley dose ratios at the position of the targeted and traversed tissues whose biological responses determine treatment outcome. The purpose of this study was to utilise γ-H2AX immunostaining as a biodosimetric tool that enables in situ biological dose mapping within an irradiated tissue to provide direct biological evidence for the scale of the radiation burden to 'spared' tissue regions between MRT tracks. Γ-H2AX analysis allowed microbeams to be traced and DNA damage foci to be quantified in valleys between beams following MRT treatment of fibroblast cultures and murine skin where foci yields per unit dose were approximately five-fold lower than in fibroblast cultures. Foci levels in cells located in valleys were compared with calibration curves using known broadbeam synchrotron X-ray doses to generate spatial dose profiles and calculate peak-to-valley dose ratios of 30-40 for cell cultures and approximately 60 for murine skin, consistent with the range obtained with conventional dosimetry methods. This biological dose mapping approach could find several applications both in optimising MRT or other radiotherapeutic treatments and in estimating localised doses following accidental radiation exposure using skin punch biopsies.

  1. Comparison of Global Cerebral Blood Flow Measured by Phase-Contrast Mapping MRI with O-15-H2O Positron Emission Tomography

    DEFF Research Database (Denmark)

    Vestergaard, Mark Bitsch; Lindberg, Ulrich; Aachmann-Andersen, Niels Jacob

    2017-01-01

    Purpose To compare mean global cerebral blood flow (CBF) measured by phase-contrast mapping magnetic resonance imaging (PCM MRI) and by 15O-H2O positron emission tomography (PET) in healthy subjects. PCM MRI is increasingly being used to measure mean global CBF, but has not been validated in vivo...... against an accepted reference technique. Materials and Methods Same-day measurements of CBF by 15O-H2O PET and subsequently by PCM MRI were performed on 22 healthy young male volunteers. Global CBF by PET was determined by applying a one-tissue compartment model with measurement of the arterial input...... function. Flow was measured in the internal carotid and vertebral arteries by a noncardiac triggered PCM MRI sequence at 3T. The measured flow was normalized to total brain weight determined from a volume-segmented 3D T1-weighted anatomical MR-scan. Results Mean CBF was 34.9 ± 3.4 mL/100 g/min measured...

  2. Quantitative Susceptibility Mapping: Contrast Mechanisms and Clinical Applications

    Science.gov (United States)

    Liu, Chunlei; Wei, Hongjiang; Gong, Nan-Jie; Cronin, Matthew; Dibb, Russel; Decker, Kyle

    2016-01-01

    Quantitative susceptibility mapping (QSM) is a recently developed MRI technique for quantifying the spatial distribution of magnetic susceptibility within biological tissues. It first uses the frequency shift in the MRI signal to map the magnetic field profile within the tissue. The resulting field map is then used to determine the spatial distribution of the underlying magnetic susceptibility by solving an inverse problem. The solution is achieved by deconvolving the field map with a dipole field, under the assumption that the magnetic field is a result of the superposition of the dipole fields generated by all voxels and that each voxel has its unique magnetic susceptibility. QSM provides improved contrast to noise ratio for certain tissues and structures compared to its magnitude counterpart. More importantly, magnetic susceptibility is a direct reflection of the molecular composition and cellular architecture of the tissue. Consequently, by quantifying magnetic susceptibility, QSM is becoming a quantitative imaging approach for characterizing normal and pathological tissue properties. This article reviews the mechanism generating susceptibility contrast within tissues and some associated applications. PMID:26844301

  3. Optical coherence elastography assesses tissue modifications in laser reshaping of cornea and cartilages

    Science.gov (United States)

    Zaitsev, V. Y.; Matveyev, A. L.; Matveev, L. A.; Gelikonov, G. V.; Omelchenko, A. I.; Shabanov, D. V.; Sovetsky, A. A.; Baum, O. I.; Vitkin, A.; Sobol, E. N.

    2018-02-01

    Non-surgical thermo-mechanical reshaping of avascular collagenous tissues (cartilages and cornea) using moderate heating by IR-laser irradiation is an emerging technology that can find important applications in visioncorrection problems and preparation of cartilaginous implants in otolaryngology. To estimate both transient interframe strains and cumulative resultant strains produced by the laser irradiation of the tissue we use and improved version of strain mapping developed in our previous work related to compressional phase-sensitive optical coherence tomography. To reveal microstructural changes in the tissue regions where irradiation-produced strains do not disappear after temperature equilibration, we apply compressional optical coherence elastography in order to visualize the resultant variations in the tissue stiffness. The so-found regions of the stiffness reduction are attributed to formation of microscopic pores, existence of which agree with independent data obtained using methods of high-resolution microscopy.

  4. Multi-phase EBSD mapping and local texture analysis in NdFeB sintered magnets

    Energy Technology Data Exchange (ETDEWEB)

    Woodcock, T.G., E-mail: t.woodcock@ifw-dresden.de [IFW Dresden, Institute for Metallic Materials, PO Box 270116, 01171 Dresden (Germany); Gutfleisch, O. [IFW Dresden, Institute for Metallic Materials, PO Box 270116, 01171 Dresden (Germany)

    2011-02-15

    A combination of electron backscatter diffraction and energy-dispersive X-ray spectroscopy has been used to identify the crystal structure and composition of all the phases present in commercially available NdFeB sintered magnets and to map their spatial distribution. The Nd{sub 2}Fe{sub 14}B and NdO grains were shown to have low defect densities. The fcc Nd-rich and Nd{sub 2}O{sub 3} grains had intra-grain misorientation angles of up to 14{sup o}, which was shown to be due to defects. Large numbers ({approx}100) of data points for each phase were used to study texture in the NdO, Nd{sub 2}O{sub 3} and Nd{sub 2}Fe{sub 14}B phases. The Nd{sub 2}Fe{sub 14}B grains exhibited a <0 0 1> fibre texture. The Nd oxide phases showed no strong texture, which implied that no strongly preferred orientation relationships between those phases and Nd{sub 2}Fe{sub 14}B exist. The result was shown to be valid for optimally annealed samples exhibiting high coercivity and as-sintered samples exhibiting low coercivity.

  5. Studies of phase return map and symbolic dynamics in a periodically driven Hodgkin—Huxley neuron

    International Nuclear Information System (INIS)

    Ding Jiong; Zhang Hong; Tong Qin-Ye; Chen Zhuo

    2014-01-01

    How neuronal spike trains encode external information is a hot topic in neurodynamics studies. In this paper, we investigate the dynamical states of the Hodgkin—Huxley neuron under periodic forcing. Depending on the parameters of the stimulus, the neuron exhibits periodic, quasiperiodic and chaotic spike trains. In order to analyze these spike trains quantitatively, we use the phase return map to describe the dynamical behavior on a one-dimensional (1D) map. According to the monotonicity or discontinuous point of the 1D map, the spike trains are transformed into symbolic sequences by implementing a coarse-grained algorithm — symbolic dynamics. Based on the ordering rules of symbolic dynamics, the parameters of the external stimulus can be measured in high resolution with finite length symbolic sequences. A reasonable explanation for why the nervous system can discriminate or cognize the small change of the external signals in a short time is also presented. (general)

  6. Crystal analyser-based X-ray phase contrast imaging in the dark field: implementation and evaluation using excised tissue specimens

    International Nuclear Information System (INIS)

    Ando, Masami; Sunaguchi, Naoki; Wu, Yanlin; Do, Synho; Sung, Yongjin; Gupta, Rajiv; Louissaint, Abner; Yuasa, Tetsuya; Ichihara, Shu

    2014-01-01

    We demonstrate the soft tissue discrimination capability of X-ray dark-field imaging (XDFI) using a variety of human tissue specimens. The experimental setup for XDFI comprises an X-ray source, an asymmetrically cut Bragg-type monochromator-collimator (MC), a Laue-case angle analyser (LAA) and a CCD camera. The specimen is placed between the MC and the LAA. For the light source, we used the beamline BL14C on a 2.5-GeV storage ring in the KEK Photon Factory, Tsukuba, Japan. In the eye specimen, phase contrast images from XDFI were able to discriminate soft-tissue structures, such as the iris, separated by aqueous humour on both sides, which have nearly equal absorption. Superiority of XDFI in imaging soft tissue was further demonstrated with a diseased iliac artery containing atherosclerotic plaque and breast samples with benign and malignant tumours. XDFI on breast tumours discriminated between the normal and diseased terminal duct lobular unit and between invasive and in-situ cancer. X-ray phase, as detected by XDFI, has superior contrast over absorption for soft tissue processes such as atherosclerotic plaque and breast cancer. (orig.)

  7. Crystal analyser-based X-ray phase contrast imaging in the dark field: implementation and evaluation using excised tissue specimens

    Energy Technology Data Exchange (ETDEWEB)

    Ando, Masami [RIST, Tokyo University of Science, Noda, Chiba (Japan); Sunaguchi, Naoki [Gunma University, Graduate School of Engineering, Kiryu, Gunma (Japan); Wu, Yanlin [The Graduate University for Advanced Studies, Department of Materials Structure Science, School of High Energy Accelerator Science, Tsukuba, Ibaraki (Japan); Do, Synho; Sung, Yongjin; Gupta, Rajiv [Massachusetts General Hospital and Harvard Medical School, Department of Radiology, Boston, MA (United States); Louissaint, Abner [Massachusetts General Hospital and Harvard Medical School, Department of Pathology, Boston, MA (United States); Yuasa, Tetsuya [Yamagata University, Faculty of Engineering, Yonezawa, Yamagata (Japan); Ichihara, Shu [Nagoya Medical Center, Department of Pathology, Nagoya, Aichi (Japan)

    2014-02-15

    We demonstrate the soft tissue discrimination capability of X-ray dark-field imaging (XDFI) using a variety of human tissue specimens. The experimental setup for XDFI comprises an X-ray source, an asymmetrically cut Bragg-type monochromator-collimator (MC), a Laue-case angle analyser (LAA) and a CCD camera. The specimen is placed between the MC and the LAA. For the light source, we used the beamline BL14C on a 2.5-GeV storage ring in the KEK Photon Factory, Tsukuba, Japan. In the eye specimen, phase contrast images from XDFI were able to discriminate soft-tissue structures, such as the iris, separated by aqueous humour on both sides, which have nearly equal absorption. Superiority of XDFI in imaging soft tissue was further demonstrated with a diseased iliac artery containing atherosclerotic plaque and breast samples with benign and malignant tumours. XDFI on breast tumours discriminated between the normal and diseased terminal duct lobular unit and between invasive and in-situ cancer. X-ray phase, as detected by XDFI, has superior contrast over absorption for soft tissue processes such as atherosclerotic plaque and breast cancer. (orig.)

  8. Physics of tissue harmonic imaging by ultrasound

    Science.gov (United States)

    Jing, Yuan

    Tissue Harmonic Imaging (THI) is an imaging modality that is currently deployed on diagnostic ultrasound scanners. In THI the amplitude of the ultrasonic pulse that is used to probe the tissue is large enough that the pulse undergoes nonlinear distortion as it propagates into the tissue. One result of the distortion is that as the pulse propagates energy is shifted from the fundamental frequency of the source pulse into its higher harmonics. These harmonics will scatter off objects in the tissue and images formed from the scattered higher harmonics are considered to have superior quality to the images formed from the fundamental frequency. Processes that have been suggested as possibly responsible for the improved imaging in THI include: (1) reduced sensitivity to reverberation, (2) reduced sensitivity to aberration, and (3) reduction in side lobes. By using a combination of controlled experiments and numerical simulations, these three reasons have been investigated. A single element transducer and a clinical ultrasound scanner with a phased array transducer were used to image a commercial tissue-mimicking phantom with calibrated targets. The higher image quality achieved with THI was quantified in terms of spatial resolution and "clutter" signals. A three-dimensional model of the forward propagation of nonlinear sound beams in media with arbitrary spatial properties (a generalized KZK equation) was developed. A time-domain code for solving the KZK equation was validated with measurements of the acoustic field generated by the single element transducer and the phased array transducer. The code was used to investigate the impact of aberration using tissue-like media with three-dimensional variations in all acoustic properties. The three-dimensional maps of tissue properties were derived from the datasets available through the Visible Female project. The experiments and simulations demonstrated that second harmonic imaging (1) suffers less clutter associated with

  9. Mapping the upper mantle beneath North American continent with joint inversion of surface-wave phase and amplitude

    Science.gov (United States)

    Yoshizawa, K.; Hamada, K.

    2017-12-01

    A new 3-D S-wave model of the North American upper mantle is constructed from a large number of inter-station phase and amplitude measurements of surface waves. A fully nonlinear waveform fitting method by Hamada and Yoshizawa (2015, GJI) is applied to USArray for measuring inter-station phase speeds and amplitude ratios of the fundamental-mode Rayleigh and Love waves. We employed the seismic events from 2007 - 2014 with Mw 6.0 or greater, and collected a large-number of inter-station phase speed data (about 130,000 for Rayleigh and 85,000 for Love waves) and amplitude ratio data (about 75,000 for Rayleigh waves) in a period range from 30 to 130 s for fundamental-mode surface waves. Typical inter-station distances are mostly in a range between 300 and 800 km, which can be of help in enhancing the lateral resolution of a regional tomography model. We first invert Rayleigh-wave phase speeds and amplitudes simultaneously for phase speed maps as well as local amplification factors at receiver locations. The isotropic 3-D S-wave model constructed from these phase speed maps incorporating both phase and amplitude data exhibits better recovery of the strength of velocity perturbations. In particular, local tectonic features characterized by strong velocity gradients, such as Rio Grande Rift, Colorado Plateau and New Madrid Seismic Zone, are more enhanced than conventional models derived from phase information only. The results indicate that surface-wave amplitude, which is sensitive to the second derivative of phase speeds, can be of great help in retrieving small-scale heterogeneity in the upper mantle. We also obtain a radial anisotropy model from the simultaneous inversions of Rayleigh and Love waves (without amplitude information). The model has shown faster SH wave speed anomalies than SV above the depth of 100 km, particularly in tectonically active regions in the western and central U.S., representing the effects of current and former tectonic processes on

  10. Cardiac tissue geometry as a determinant of unidirectional conduction block: assessment of microscopic excitation spread by optical mapping in patterned cell cultures and in a computer model.

    Science.gov (United States)

    Fast, V G; Kléber, A G

    1995-05-01

    Unidirectional conduction block (UCB) and reentry may occur as a consequence of an abrupt tissue expansion and a related change in the electrical load. The aim of this study was to evaluate critical dimensions of the tissue necessary for establishing UCB in heart cell culture. Neonatal rat heart cell cultures with cell strands of variable width emerging into a large cell area were grown using a technique of patterned cell growth. Action potential upstrokes were measured using a voltage sensitive dye (RH-237) and a linear array of 10 photodiodes with a 15 microns resolution. A mathematical model was used to relate action potential wave shapes to underlying ionic currents. UCB (block of a single impulse in anterograde direction - from a strand to a large area - and conduction in the retrograde direction) occurred in narrow cell strands with a width of 15(SD 4) microns (1-2 cells in width, n = 7) and there was no conduction block in strands with a width of 31(8) microns (n = 9, P multiple rising phases. Mathematical modelling showed that two rising phases were caused by electronic current flow, whereas local ionic current did not coincide with the rising portions of the upstrokes. (1) High resolution optical mapping shows multiphasic action potential upstrokes at the region of abrupt expansion. At the site of the maximum decrement in conduction, these peaks were largely determined by the electrotonus and not by the local ionic current. (2) Unidirectional conduction block occurred in strands with a width of 15(4) microns (1-2 cells).

  11. Transverse phase space mapping of relativistic electron beams using optical transition radiation

    Directory of Open Access Journals (Sweden)

    G. P. Le Sage

    1999-12-01

    Full Text Available Optical transition radiation (OTR has proven to be a versatile and effective diagnostic for measuring the profile, divergence, and emittance of relativistic electron beams with a wide range of parameters. Diagnosis of the divergence of modern high brightness beams is especially well suited to OTR interference (OTRI techniques, where multiple dielectric or metal foils are used to generate a spatially coherent interference pattern. Theoretical analysis of measured OTR and OTRI patterns allows precise measurement of electron beam emittance characteristics. Here we describe an extension of this technique to allow mapping of divergence characteristics as a function of transverse coordinates within a measured beam. We present the first experimental analysis of the transverse phase space of an electron beam using all optical techniques. Comparing an optically masked portion of the beam to the entire beam, we measure different angular spread and average direction of the particles. Direct measurement of the phase-space ellipse tilt angle has been demonstrated using this optical masking technique.

  12. Soft tissue freezing process. Identification of the dual-phase lag model parameters using the evolutionary algorithm

    Science.gov (United States)

    Mochnacki, Bohdan; Majchrzak, Ewa; Paruch, Marek

    2018-01-01

    In the paper the soft tissue freezing process is considered. The tissue sub-domain is subjected to the action of cylindrical cryoprobe. Thermal processes proceeding in the domain considered are described using the dual-phase lag equation (DPLE) supplemented by the appropriate boundary and initial conditions. DPLE results from the generalization of the Fourier law in which two lag times are introduced (relaxation and thermalization times). The aim of research is the identification of these parameters on the basis of measured cooling curves at the set of points selected from the tissue domain. To solve the problem the evolutionary algorithms are used. The paper contains the mathematical model of the tissue freezing process, the very short information concerning the numerical solution of the basic problem, the description of the inverse problem solution and the results of computations.

  13. Robustness of phase retrieval methods in x-ray phase contrast imaging: A comparison

    International Nuclear Information System (INIS)

    Yan, Aimin; Wu, Xizeng; Liu, Hong

    2011-01-01

    Purpose: The robustness of the phase retrieval methods is of critical importance for limiting and reducing radiation doses involved in x-ray phase contrast imaging. This work is to compare the robustness of two phase retrieval methods by analyzing the phase maps retrieved from the experimental images of a phantom. Methods: Two phase retrieval methods were compared. One method is based on the transport of intensity equation (TIE) for phase contrast projections, and the TIE-based method is the most commonly used method for phase retrieval in the literature. The other is the recently developed attenuation-partition based (AP-based) phase retrieval method. The authors applied these two methods to experimental projection images of an air-bubble wrap phantom for retrieving the phase map of the bubble wrap. The retrieved phase maps obtained by using the two methods are compared. Results: In the wrap's phase map retrieved by using the TIE-based method, no bubble is recognizable, hence, this method failed completely for phase retrieval from these bubble wrap images. Even with the help of the Tikhonov regularization, the bubbles are still hardly visible and buried in the cluttered background in the retrieved phase map. The retrieved phase values with this method are grossly erroneous. In contrast, in the wrap's phase map retrieved by using the AP-based method, the bubbles are clearly recovered. The retrieved phase values with the AP-based method are reasonably close to the estimate based on the thickness-based measurement. The authors traced these stark performance differences of the two methods to their different techniques employed to deal with the singularity problem involved in the phase retrievals. Conclusions: This comparison shows that the conventional TIE-based phase retrieval method, regardless if Tikhonov regularization is used or not, is unstable against the noise in the wrap's projection images, while the AP-based phase retrieval method is shown in these

  14. Mueller-matrix mapping of biological tissues in differential diagnosis of optical anisotropy mechanisms of protein networks

    Energy Technology Data Exchange (ETDEWEB)

    Ushenko, V A; Sidor, M I [Yuriy Fedkovych Chernivtsi National University, Chernivtsi (Ukraine); Marchuk, Yu F; Pashkovskaya, N V; Andreichuk, D R [Bukovinian State Medical University, Chernivtsi (Ukraine)

    2015-03-31

    We report a model of Mueller-matrix description of optical anisotropy of protein networks in biological tissues with allowance for the linear birefringence and dichroism. The model is used to construct the reconstruction algorithms of coordinate distributions of phase shifts and the linear dichroism coefficient. In the statistical analysis of such distributions, we have found the objective criteria of differentiation between benign and malignant tissues of the female reproductive system. From the standpoint of evidence-based medicine, we have determined the operating characteristics (sensitivity, specificity and accuracy) of the Mueller-matrix reconstruction method of optical anisotropy parameters and demonstrated its effectiveness in the differentiation of benign and malignant tumours. (laser applications and other topics in quantum electronics)

  15. High-speed single-shot optical focusing through dynamic scattering media with full-phase wavefront shaping

    Science.gov (United States)

    Hemphill, Ashton S.; Shen, Yuecheng; Liu, Yan; Wang, Lihong V.

    2017-11-01

    In biological applications, optical focusing is limited by the diffusion of light, which prevents focusing at depths greater than ˜1 mm in soft tissue. Wavefront shaping extends the depth by compensating for phase distortions induced by scattering and thus allows for focusing light through biological tissue beyond the optical diffusion limit by using constructive interference. However, due to physiological motion, light scattering in tissue is deterministic only within a brief speckle correlation time. In in vivo tissue, this speckle correlation time is on the order of milliseconds, and so the wavefront must be optimized within this brief period. The speed of digital wavefront shaping has typically been limited by the relatively long time required to measure and display the optimal phase pattern. This limitation stems from the low speeds of cameras, data transfer and processing, and spatial light modulators. While binary-phase modulation requiring only two images for the phase measurement has recently been reported, most techniques require at least three frames for the full-phase measurement. Here, we present a full-phase digital optical phase conjugation method based on off-axis holography for single-shot optical focusing through scattering media. By using off-axis holography in conjunction with graphics processing unit based processing, we take advantage of the single-shot full-phase measurement while using parallel computation to quickly reconstruct the phase map. With this system, we can focus light through scattering media with a system latency of approximately 9 ms, on the order of the in vivo speckle correlation time.

  16. Self-organizing maps applied to two-phase flow on natural circulation loop study

    International Nuclear Information System (INIS)

    Castro, Leonardo Ferreira

    2016-01-01

    Two-phase flow of liquid and gas is found in many closed circuits using natural circulation for cooling purposes. Natural circulation phenomenon is important on recent nuclear power plant projects for decay heat removal. The Natural Circulation Facility (Circuito de Circulacao Natural CCN) installed at Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN, is an experimental circuit designed to provide thermal hydraulic data related to single and two-phase flow under natural circulation conditions. This periodic flow oscillation behavior can be observed thoroughly in this facility due its glass-made tubes transparency. The heat transfer estimation has been improved based on models that require precise prediction of pattern transitions of flow. This work presents experiments realized at CCN to visualize natural circulation cycles in order to classify two-phase flow patterns associated with phase transients and static instabilities of flow. Images are compared and clustered using Kohonen Self-organizing Maps (SOM's) applied on different digital image features. The Full Frame Discret Cosine Transform (FFDCT) coefficients were used as input for the classification task, enabling good results. FFDCT prototypes obtained can be associated to each flow pattern, enabling a better comprehension of each observed instability. A systematic test methodology was used to verify classifier robustness.

  17. Molecular cloning, genomic organization, chromosome mapping, tissues expression pattern and identification of a novel splicing variant of porcine CIDEb gene

    International Nuclear Information System (INIS)

    Li, YanHua; Li, AiHua; Yang, Z.Q.

    2016-01-01

    Cell death-inducing DNA fragmentation factor-α-like effector b (CIDEb) is a member of the CIDE family of apoptosis-inducing factors, CIDEa and CIDEc have been reported to be Lipid droplets (LDs)-associated proteins that promote atypical LD fusion in adipocytes, and responsible for liver steatosis under fasting and obese conditions, whereas CIDEb promotes lipid storage under normal diet conditions [1], and promotes the formation of triacylglyceride-enriched VLDL particles in hepatocytes [2]. Here, we report the gene cloning, chromosome mapping, tissue distribution, genetic expression analysis, and identification of a novel splicing variant of the porcine CIDEb gene. Sequence analysis shows that the open reading frame of the normal porcine CIDEb isoform covers 660bp and encodes a 219-amino acid polypeptide, whereas its alternative splicing variant encodes a 142-amino acid polypeptide truncated at the fourth exon and comprised of the CIDE-N domain and part of the CIDE-C domain. The deduced amino acid sequence of normal porcine CIDEb shows an 85.8% similarity to the human protein and 80.0% to the mouse protein. The CIDEb genomic sequence spans approximately 6KB comprised of five exons and four introns. Radiation hybrid mapping demonstrated that porcine CIDEb is located at chromosome 7q21 and at a distance of 57cR from the most significantly linked marker, S0334, regions that are syntenic with the corresponding region in the human genome. Tissue expression analysis indicated that normal CIDEb mRNA is ubiquitously expressed in many porcine tissues. It was highly expressed in white adipose tissue and was observed at relatively high levels in the liver, lung, small intestine, lymphatic tissue and brain. The normal version of CIDEb was the predominant form in all tested tissues, whereas the splicing variant was expressed at low levels in all examined tissues except the lymphatic tissue. Furthermore, genetic expression analysis indicated that CIDEb mRNA levels were

  18. Molecular cloning, genomic organization, chromosome mapping, tissues expression pattern and identification of a novel splicing variant of porcine CIDEb gene

    Energy Technology Data Exchange (ETDEWEB)

    Li, YanHua, E-mail: liyanhua.1982@aliyun.com [Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Children’s Hospital of Chongqing Medical University, Chongqing 400014 (China); Li, AiHua [Chongqing Cancer Institute & Hospital & Cancer Center, Chongqing 404100 (China); Yang, Z.Q. [Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070 (China)

    2016-09-09

    Cell death-inducing DNA fragmentation factor-α-like effector b (CIDEb) is a member of the CIDE family of apoptosis-inducing factors, CIDEa and CIDEc have been reported to be Lipid droplets (LDs)-associated proteins that promote atypical LD fusion in adipocytes, and responsible for liver steatosis under fasting and obese conditions, whereas CIDEb promotes lipid storage under normal diet conditions [1], and promotes the formation of triacylglyceride-enriched VLDL particles in hepatocytes [2]. Here, we report the gene cloning, chromosome mapping, tissue distribution, genetic expression analysis, and identification of a novel splicing variant of the porcine CIDEb gene. Sequence analysis shows that the open reading frame of the normal porcine CIDEb isoform covers 660bp and encodes a 219-amino acid polypeptide, whereas its alternative splicing variant encodes a 142-amino acid polypeptide truncated at the fourth exon and comprised of the CIDE-N domain and part of the CIDE-C domain. The deduced amino acid sequence of normal porcine CIDEb shows an 85.8% similarity to the human protein and 80.0% to the mouse protein. The CIDEb genomic sequence spans approximately 6KB comprised of five exons and four introns. Radiation hybrid mapping demonstrated that porcine CIDEb is located at chromosome 7q21 and at a distance of 57cR from the most significantly linked marker, S0334, regions that are syntenic with the corresponding region in the human genome. Tissue expression analysis indicated that normal CIDEb mRNA is ubiquitously expressed in many porcine tissues. It was highly expressed in white adipose tissue and was observed at relatively high levels in the liver, lung, small intestine, lymphatic tissue and brain. The normal version of CIDEb was the predominant form in all tested tissues, whereas the splicing variant was expressed at low levels in all examined tissues except the lymphatic tissue. Furthermore, genetic expression analysis indicated that CIDEb mRNA levels were

  19. Combinatorial materials synthesis and high-throughput screening: an integrated materials chip approach to mapping phase diagrams and discovery and optimization of functional materials.

    Science.gov (United States)

    Xiang, X D

    Combinatorial materials synthesis methods and high-throughput evaluation techniques have been developed to accelerate the process of materials discovery and optimization and phase-diagram mapping. Analogous to integrated circuit chips, integrated materials chips containing thousands of discrete different compositions or continuous phase diagrams, often in the form of high-quality epitaxial thin films, can be fabricated and screened for interesting properties. Microspot x-ray method, various optical measurement techniques, and a novel evanescent microwave microscope have been used to characterize the structural, optical, magnetic, and electrical properties of samples on the materials chips. These techniques are routinely used to discover/optimize and map phase diagrams of ferroelectric, dielectric, optical, magnetic, and superconducting materials.

  20. Feasibility of Imaging Tissue Electrical Conductivity by Switching Field Gradients with MRI.

    Science.gov (United States)

    Gibbs, Eric; Liu, Chunlei

    2015-12-01

    Tissue conductivity is a biophysical marker of tissue structure and physiology. Present methods of measuring tissue conductivity are limited. Electrical impedance tomography, and magnetic resonance electrical impedance tomography rely on passing external current through the object being imaged, which prevents its use in most human imaging. Recently, the RF field used for MR excitation has been used to non-invasively measure tissue conductivity. This technique is promising, but conductivity at higher frequencies is less sensitive to tissue structure. Measuring tissue conductivity non-invasively at low frequencies remains elusive. It has been proposed that eddy currents generated during the rise and decay of gradient pulses could act as a current source to map low-frequency conductivity. This work centers on a gradient echo pulse sequence that uses large gradients prior to excitation to create eddy currents. The electric and magnetic fields during a gradient pulse are simulated by a finite-difference time-domain simulation. The sequence is also tested with a phantom and an animal MRI scanner equipped with gradients of high gradient strengths and slew rate. The simulation demonstrates that eddy currents in materials with conductivity similar to biological tissue decay with a half-life on the order of nanoseconds and any eddy currents generated prior to excitation decay completely before influencing the RF signal. Gradient-induced eddy currents can influence phase accumulation after excitation but the effect is too small to image. The animal scanner images show no measurable phase accumulation. Measuring low-frequency conductivity by gradient-induced eddy currents is presently unfeasible.

  1. Mapping the conformational free energy of aspartic acid in the gas phase and in aqueous solution.

    Science.gov (United States)

    Comitani, Federico; Rossi, Kevin; Ceriotti, Michele; Sanz, M Eugenia; Molteni, Carla

    2017-04-14

    The conformational free energy landscape of aspartic acid, a proteogenic amino acid involved in a wide variety of biological functions, was investigated as an example of the complexity that multiple rotatable bonds produce even in relatively simple molecules. To efficiently explore such a landscape, this molecule was studied in the neutral and zwitterionic forms, in the gas phase and in water solution, by means of molecular dynamics and the enhanced sampling method metadynamics with classical force-fields. Multi-dimensional free energy landscapes were reduced to bi-dimensional maps through the non-linear dimensionality reduction algorithm sketch-map to identify the energetically stable conformers and their interconnection paths. Quantum chemical calculations were then performed on the minimum free energy structures. Our procedure returned the low energy conformations observed experimentally in the gas phase with rotational spectroscopy [M. E. Sanz et al., Phys. Chem. Chem. Phys. 12, 3573 (2010)]. Moreover, it provided information on higher energy conformers not accessible to experiments and on the conformers in water. The comparison between different force-fields and quantum chemical data highlighted the importance of the underlying potential energy surface to accurately capture energy rankings. The combination of force-field based metadynamics, sketch-map analysis, and quantum chemical calculations was able to produce an exhaustive conformational exploration in a range of significant free energies that complements the experimental data. Similar protocols can be applied to larger peptides with complex conformational landscapes and would greatly benefit from the next generation of accurate force-fields.

  2. Mapping the conformational free energy of aspartic acid in the gas phase and in aqueous solution

    Science.gov (United States)

    Comitani, Federico; Rossi, Kevin; Ceriotti, Michele; Sanz, M. Eugenia; Molteni, Carla

    2017-04-01

    The conformational free energy landscape of aspartic acid, a proteogenic amino acid involved in a wide variety of biological functions, was investigated as an example of the complexity that multiple rotatable bonds produce even in relatively simple molecules. To efficiently explore such a landscape, this molecule was studied in the neutral and zwitterionic forms, in the gas phase and in water solution, by means of molecular dynamics and the enhanced sampling method metadynamics with classical force-fields. Multi-dimensional free energy landscapes were reduced to bi-dimensional maps through the non-linear dimensionality reduction algorithm sketch-map to identify the energetically stable conformers and their interconnection paths. Quantum chemical calculations were then performed on the minimum free energy structures. Our procedure returned the low energy conformations observed experimentally in the gas phase with rotational spectroscopy [M. E. Sanz et al., Phys. Chem. Chem. Phys. 12, 3573 (2010)]. Moreover, it provided information on higher energy conformers not accessible to experiments and on the conformers in water. The comparison between different force-fields and quantum chemical data highlighted the importance of the underlying potential energy surface to accurately capture energy rankings. The combination of force-field based metadynamics, sketch-map analysis, and quantum chemical calculations was able to produce an exhaustive conformational exploration in a range of significant free energies that complements the experimental data. Similar protocols can be applied to larger peptides with complex conformational landscapes and would greatly benefit from the next generation of accurate force-fields.

  3. Background field removal using a region adaptive kernel for quantitative susceptibility mapping of human brain

    Science.gov (United States)

    Fang, Jinsheng; Bao, Lijun; Li, Xu; van Zijl, Peter C. M.; Chen, Zhong

    2017-08-01

    Background field removal is an important MR phase preprocessing step for quantitative susceptibility mapping (QSM). It separates the local field induced by tissue magnetic susceptibility sources from the background field generated by sources outside a region of interest, e.g. brain, such as air-tissue interface. In the vicinity of air-tissue boundary, e.g. skull and paranasal sinuses, where large susceptibility variations exist, present background field removal methods are usually insufficient and these regions often need to be excluded by brain mask erosion at the expense of losing information of local field and thus susceptibility measures in these regions. In this paper, we propose an extension to the variable-kernel sophisticated harmonic artifact reduction for phase data (V-SHARP) background field removal method using a region adaptive kernel (R-SHARP), in which a scalable spherical Gaussian kernel (SGK) is employed with its kernel radius and weights adjustable according to an energy "functional" reflecting the magnitude of field variation. Such an energy functional is defined in terms of a contour and two fitting functions incorporating regularization terms, from which a curve evolution model in level set formation is derived for energy minimization. We utilize it to detect regions of with a large field gradient caused by strong susceptibility variation. In such regions, the SGK will have a small radius and high weight at the sphere center in a manner adaptive to the voxel energy of the field perturbation. Using the proposed method, the background field generated from external sources can be effectively removed to get a more accurate estimation of the local field and thus of the QSM dipole inversion to map local tissue susceptibility sources. Numerical simulation, phantom and in vivo human brain data demonstrate improved performance of R-SHARP compared to V-SHARP and RESHARP (regularization enabled SHARP) methods, even when the whole paranasal sinus regions

  4. Mapping of the spatial distribution of silver nanoparticles in root tissues of Vicia faba by laser-induced breakdown spectroscopy (LIBS).

    Science.gov (United States)

    Krajcarová, L; Novotný, K; Kummerová, M; Dubová, J; Gloser, V; Kaiser, J

    2017-10-01

    The manuscript presents a procedure for optimal sample preparation and the mapping of the spatial distribution of metal ions and nanoparticles in plant roots using laser-induced breakdown spectroscopy (LIBS) in a double-pulse configuration (DP LIBS) in orthogonal reheating mode. Two Nd:YAG lasers were used; the first one was an ablation laser (UP-266 MACRO, New Wave, USA) with a wavelength of 266nm, and the second one (Brilliant, Quantel, France), with a fundamental wavelength of 1064nm, was used to reheat the microplasma. Seedlings of Vicia faba were cultivated for 7 days in CuSO 4 or AgNO 3 solutions with a concentration of 10µmoll -1 or in a solution of silver nanoparticles (AgNPs) with a concentration of 10µmoll -1 of total Ag, and in distilled water as a control. The total contents of the examined metals in the roots after sample mineralization as well as changes in the concentrations of the metals in the cultivation solutions were monitored by ICP-OES. Root samples embedded in the TissueTek medium and cut into 40µm thick cross sections using the Cryo-Cut Microtome proved to be best suited for an accurate LIBS analysis with a 50µm spatial resolution. 2D raster maps of elemental distribution were created for the emission lines of Cu(I) at 324.754nm and Ag(I) at 328.068nm. The limits of detection of DP LIBS for the root cross sections were estimated to be 4pg for Cu, 18pg for Ag, and 3pg for AgNPs. The results of Ag spatial distribution mapping indicated that unlike Ag + ions, AgNPs do not penetrate into the inner tissues of Vicia faba roots but stay in their outermost layers. The content of Ag in roots cultivated in the AgNP solution was one order of magnitude lower compared to roots cultivated in the metal ion solutions. The significantly smaller concentration of Ag in root tissues cultivated in the AgNP solution also supports the conclusion that the absorption and uptake of AgNPs by roots of Vicia faba is very slow. LIBS mapping of root sections

  5. Fast phase processing in off-axis holography by CUDA including parallel phase unwrapping.

    Science.gov (United States)

    Backoach, Ohad; Kariv, Saar; Girshovitz, Pinhas; Shaked, Natan T

    2016-02-22

    We present parallel processing implementation for rapid extraction of the quantitative phase maps from off-axis holograms on the Graphics Processing Unit (GPU) of the computer using computer unified device architecture (CUDA) programming. To obtain efficient implementation, we parallelized both the wrapped phase map extraction algorithm and the two-dimensional phase unwrapping algorithm. In contrast to previous implementations, we utilized unweighted least squares phase unwrapping algorithm that better suits parallelism. We compared the proposed algorithm run times on the CPU and the GPU of the computer for various sizes of off-axis holograms. Using the GPU implementation, we extracted the unwrapped phase maps from the recorded off-axis holograms at 35 frames per second (fps) for 4 mega pixel holograms, and at 129 fps for 1 mega pixel holograms, which presents the fastest processing framerates obtained so far, to the best of our knowledge. We then used common-path off-axis interferometric imaging to quantitatively capture the phase maps of a micro-organism with rapid flagellum movements.

  6. Validity of T2 mapping in characterization of the regeneration tissue by bone marrow derived cell transplantation in osteochondral lesions of the ankle

    Energy Technology Data Exchange (ETDEWEB)

    Battaglia, M., E-mail: milva.battaglia@ior.it [Service of Ecography and Radiology, Rizzoli Orthopaedic Institute, via Pupilli n. 1, 40136 Bologna (Italy); Rimondi, E. [Service of Ecography and Radiology, Rizzoli Orthopaedic Institute, via Pupilli n. 1, 40136 Bologna (Italy); Monti, C. [Service of CT and MRI, Casa di Cura Madre Fortunata Toniolo, Bologna (Italy); Guaraldi, F. [Department of Pathology, The Johns Hopkins University, School of Medicine, Baltimore, MD (United States); Sant' Andrea, A. [Service of CT and MRI, Casa di Cura Madre Fortunata Toniolo, Bologna (Italy); Buda, R.; Cavallo, M.; Giannini, S.; Vannini, F. [Clinical Orthopaedic and Traumatology Unit II, Rizzoli Orthopaedic Institute, Bologna (Italy)

    2011-11-15

    Objective: Bone marrow derived cell transplantation (BMDCT) has been recently suggested as a possible surgical technique to repair osteochondral lesions. To date, no qualitative MRI studies have evaluated its efficacy. The aim of our study is to investigate the validity of MRI T2-mapping sequence in characterizing the reparative tissue obtained and its ability to correlate with clinical results. Methods and materials: 20 patients with an osteochondral lesion of the talus underwent BMDCT and were evaluated at 2 years follow up using MRI T2-mapping sequence. 20 healthy volunteers were recruited as controls. MRI images were acquired using a protocol suggested by the International Cartilage Repair Society, MOCART scoring system and T2 mapping. Results were then correlated with AOFAS clinical score. Results: AOFAS score increased from 66.8 {+-} 14.5 pre-operatively to 91.2 {+-} 8.3 (p < 0.0005) at 2 years follow-up. T2-relaxation time value of 35-45 ms was derived from healthy ankles evaluation and assumed as normal hyaline cartilage value and used as a control. Regenerated tissue with a T2-relaxation time value comparable to hyaline cartilage was found in all the cases treated, covering a mean of 78% of the repaired lesion area. A high clinical score was related directly to isointense signal in DPFSE fat sat (p = 0.05), and percentage of regenerated hyaline cartilage (p = 0.05), inversely to the percentage of regenerated fibrocartilage. Lesion's depth negatively related to the integrity of the repaired tissue's surface (tau = -0.523, p = 0.007), and to the percentage of regenerated hyaline cartilage (rho = -0.546, p = 0.013). Conclusions: Because of its ability to detect cartilage's quality and to correlate to the clinical score, MRI T2-mapping sequence integrated with Mocart score represent a valid, non-invasive technique for qualitative cartilage assessment after regenerative surgical procedures.

  7. Tissue reduction of map numbers after post-exposure vaccination with single latency antigen is improved by combination with acute-stage antigens in goats

    DEFF Research Database (Denmark)

    Thakur, Aneesh; Aagaard, C.; Melvang, Heidi Mikkelsen

    compared to unvaccinated control goats. FET11 and FET13 vaccination, however, provided significantly protection with absent or very low Map numbers in tissues. No goats seroconverted in ID Screen® ELISA, except for a single goat in the unvaccinated control group at last sampling prior to euthanasia. PPDj...

  8. Third order harmonic imaging for biological tissues using three phase-coded pulses.

    Science.gov (United States)

    Ma, Qingyu; Gong, Xiufen; Zhang, Dong

    2006-12-22

    Compared to the fundamental and the second harmonic imaging, the third harmonic imaging shows significant improvements in image quality due to the better resolution, but it is degraded by the lower sound pressure and signal-to-noise ratio (SNR). In this study, a phase-coded pulse technique is proposed to selectively enhance the sound pressure of the third harmonic by 9.5 dB whereas the fundamental and the second harmonic components are efficiently suppressed and SNR is also increased by 4.7 dB. Based on the solution of the KZK nonlinear equation, the axial and lateral beam profiles of harmonics radiated from a planar piston transducer were theoretically simulated and experimentally examined. Finally, the third harmonic images using this technique were performed for several biological tissues and compared with the images obtained by the fundamental and the second harmonic imaging. Results demonstrate that the phase-coded pulse technique yields a dramatically cleaner and sharper contrast image.

  9. COAST Map Sharing Plugin, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose the development of a capability which will allow ecosystem managers to share a map view in terms of location, magnification level, and data layers (to...

  10. Generating Multi-Destination Maps.

    Science.gov (United States)

    Zhang, Junsong; Fan, Jiepeng; Luo, Zhenshan

    2017-08-01

    Multi-destination maps are a kind of navigation maps aimed to guide visitors to multiple destinations within a region, which can be of great help to urban visitors. However, they have not been developed in the current online map service. To address this issue, we introduce a novel layout model designed especially for generating multi-destination maps, which considers the global and local layout of a multi-destination map. We model the layout problem as a graph drawing that satisfies a set of hard and soft constraints. In the global layout phase, we balance the scale factor between ROIs. In the local layout phase, we make all edges have good visibility and optimize the map layout to preserve the relative length and angle of roads. We also propose a perturbation-based optimization method to find an optimal layout in the complex solution space. The multi-destination maps generated by our system are potential feasible on the modern mobile devices and our result can show an overview and a detail view of the whole map at the same time. In addition, we perform a user study to evaluate the effectiveness of our method, and the results prove that the multi-destination maps achieve our goals well.

  11. Self-organizing maps applied to two-phase flow on natural circulation loop studies

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Leonardo F.; Cunha, Kelly de P.; Andrade, Delvonei A.; Sabundjian, Gaiane; Torres, Walmir M.; Macedo, Luiz A.; Rocha, Marcelo da S.; Masotti, Paulo H.F.; Mesquita, Roberto N. de, E-mail: rnavarro@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Two-phase flow of liquid and gas is found in many closed circuits using natural circulation for cooling purposes. Natural circulation phenomenon is important on recent nuclear power plant projects for heat removal on 'loss of pump power' or 'plant shutdown' accidents. The accuracy of heat transfer estimation has been improved based on models that require precise prediction of pattern transitions of flow. Self-Organizing Maps are trained to digital images acquired on natural circulation flow instabilities. This technique will allow the selection of the more important characteristics associated with each flow pattern, enabling a better comprehension of each observed instability. This periodic flow oscillation behavior can be observed thoroughly in this facility due its glass-made tubes transparency. The Natural Circulation Facility (Circuito de Circulacao Natural - CCN) installed at Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN, is an experimental circuit designed to provide thermal hydraulic data related to one and two phase flow under natural circulation conditions. (author)

  12. Quantization of liver tissue in dual kVp computed tomography using linear discriminant analysis

    Science.gov (United States)

    Tkaczyk, J. Eric; Langan, David; Wu, Xiaoye; Xu, Daniel; Benson, Thomas; Pack, Jed D.; Schmitz, Andrea; Hara, Amy; Palicek, William; Licato, Paul; Leverentz, Jaynne

    2009-02-01

    Linear discriminate analysis (LDA) is applied to dual kVp CT and used for tissue characterization. The potential to quantitatively model both malignant and benign, hypo-intense liver lesions is evaluated by analysis of portal-phase, intravenous CT scan data obtained on human patients. Masses with an a priori classification are mapped to a distribution of points in basis material space. The degree of localization of tissue types in the material basis space is related to both quantum noise and real compositional differences. The density maps are analyzed with LDA and studied with system simulations to differentiate these factors. The discriminant analysis is formulated so as to incorporate the known statistical properties of the data. Effective kVp separation and mAs relates to precision of tissue localization. Bias in the material position is related to the degree of X-ray scatter and partial-volume effect. Experimental data and simulations demonstrate that for single energy (HU) imaging or image-based decomposition pixel values of water-like tissues depend on proximity to other iodine-filled bodies. Beam-hardening errors cause a shift in image value on the scale of that difference sought between in cancerous and cystic lessons. In contrast, projection-based decomposition or its equivalent when implemented on a carefully calibrated system can provide accurate data. On such a system, LDA may provide novel quantitative capabilities for tissue characterization in dual energy CT.

  13. Temperature mapping using proton phase shift on a 0.3 T permanent magnet open MRI system

    International Nuclear Information System (INIS)

    Komura, Kazumi; Takahashi, Tetsuhiko; Dohi, Michiko; Harada, Junta

    2000-01-01

    Temperature mapping using proton phase shift (PPS) was evaluated for ex vivo objects. The evaluation was done on a 0.3 T permanent magnet open magnetic resonance imaging (MRI) machine, like those widely used for clinical diagnosis. Temperature maps were acquired using a gradient echo sequence (TR/TE =80/30 ms, flip angle =60 degrees, field of view =200 x 200 mm, slice thickness =8 mm, matrix size =128 x 128, data acquisition number =1, and imaging time =10.2 s). Specific first order data correction was performed to eliminate calculated temperature fluctuation due to magnetic field instability. A ham, 10 cm in diameter, was heated with a Nd: YAG laser with a wavelength of 1064 nm. The laser fiber was inserted into the ham to a depth of 3 cm. The laser power was 5, 8, or 10 W. Magnetic resonance images were taken continually during and after irradiation. Temperature maps were taken every 15 s. The maps taken during laser ablation showed color changes for the heated areas. Temperatures measured by the MRI and thermocouple had a linear relationship of r 2 =0.80. The inter-image standard deviation of the temperature maps of a non-heated object was 2.07 degrees for a 4.68 x 4.68 x 8 mm volume. This value is negligible for a monitored laser heating process since temperature rise is typically larger than 30 degrees. These results show that temperature mapping based on PPS is feasible for a 0.3 T permanent magnet open MRI system. (author)

  14. DNA methylation map in circulating leukocytes mirrors subcutaneous adipose tissue methylation pattern: a genome-wide analysis from non-obese and obese patients

    Science.gov (United States)

    Crujeiras, A. B.; Diaz-Lagares, A.; Sandoval, J.; Milagro, F. I.; Navas-Carretero, S.; Carreira, M. C.; Gomez, A.; Hervas, D.; Monteiro, M. P.; Casanueva, F. F.; Esteller, M.; Martinez, J. A.

    2017-01-01

    The characterization of the epigenetic changes within the obesity-related adipose tissue will provide new insights to understand this metabolic disorder, but adipose tissue is not easy to sample in population-based studies. We aimed to evaluate the capacity of circulating leukocytes to reflect the adipose tissue-specific DNA methylation status of obesity susceptibility. DNA samples isolated from subcutaneous adipose tissue and circulating leukocytes were hybridized in the Infinium HumanMethylation 450 BeadChip. Data were compared between samples from obese (n = 45) and non-obese (n = 8–10) patients by Wilcoxon-rank test, unadjusted for cell type distributions. A global hypomethylation of the differentially methylated CpG sites (DMCpGs) was observed in the obese subcutaneous adipose tissue and leukocytes. The overlap analysis yielded a number of genes mapped by the common DMCpGs that were identified to reflect the obesity state in the leukocytes. Specifically, the methylation levels of FGFRL1, NCAPH2, PNKD and SMAD3 exhibited excellent and statistically significant efficiencies in the discrimination of obesity from non-obesity status (AUC > 0.80; p obesity-related adipose tissue pathogenesis through peripheral blood analysis, an easily accessible and minimally invasive biological material instead of adipose tissue. PMID:28211912

  15. Seiberg–Witten map and quantum phase effects for neutral Dirac particle on noncommutative plane

    Directory of Open Access Journals (Sweden)

    Kai Ma

    2016-05-01

    Full Text Available We provide a new approach to study the noncommutative effects on the neutral Dirac particle with anomalous magnetic or electric dipole moment on the noncommutative plane. The advantages of this approach are demonstrated by investigating the noncommutative corrections on the Aharonov–Casher and He–McKellar–Wilkens effects. This approach is based on the effective U(1 gauge symmetry for the electrodynamics of spin on the two dimensional space. The Seiberg–Witten map for this symmetry is then employed when we study the noncommutative corrections. Because the Seiberg–Witten map preserves the gauge symmetry, the noncommutative corrections can be defined consistently with the ordinary phases. Based on this approach we find the noncommutative corrections on the Aharonov–Casher and He–McKellar–Wilkens phases consist of two terms. The first one depends on the beam particle velocity and consistence with the previous results. However the second term is velocity-independent and then completely new. Therefore our results indicate it is possible to investigate the noncommutative space by using ultra-cold neutron interferometer in which the velocity-dependent term is negligible. Furthermore, both these two terms are proportional to the ratio between the noncommutative parameter θ and the cross section Ae/m of the electrical/magnetic charged line enclosed by the trajectory of beam particles. Therefore the experimental sensitivity can be significantly enhanced by reducing the cross section of the charge line Ae/m.

  16. Multiscale phase mapping of LiFePO4-based electrodes by transmission electron microscopy and electron forward scattering diffraction.

    Science.gov (United States)

    Robert, Donatien; Douillard, Thierry; Boulineau, Adrien; Brunetti, Guillaume; Nowakowski, Pawel; Venet, Denis; Bayle-Guillemaud, Pascale; Cayron, Cyril

    2013-12-23

    LiFePO4 and FePO4 phase distributions of entire cross-sectioned electrodes with various Li content are investigated from nanoscale to mesoscale, by transmission electron microscopy and by the new electron forward scattering diffraction technique. The distributions of the fully delithiated (FePO4) or lithiated particles (LiFePO4) are mapped on large fields of view (>100 × 100 μm(2)). Heterogeneities in thin and thick electrodes are highlighted at different scales. At the nanoscale, the statistical analysis of 64 000 particles unambiguously shows that the small particles delithiate first. At the mesoscale, the phase maps reveal a core-shell mechanism at the scale of the agglomerates with a preferential pathway along the electrode porosities. At larger scale, lithiation occurs in thick electrodes "stratum by stratum" from the surface in contact with electrolyte toward the current collector.

  17. CrowdPhase: crowdsourcing the phase problem

    International Nuclear Information System (INIS)

    Jorda, Julien; Sawaya, Michael R.; Yeates, Todd O.

    2014-01-01

    The idea of attacking the phase problem by crowdsourcing is introduced. Using an interactive, multi-player, web-based system, participants work simultaneously to select phase sets that correspond to better electron-density maps in order to solve low-resolution phasing problems. The human mind innately excels at some complex tasks that are difficult to solve using computers alone. For complex problems amenable to parallelization, strategies can be developed to exploit human intelligence in a collective form: such approaches are sometimes referred to as ‘crowdsourcing’. Here, a first attempt at a crowdsourced approach for low-resolution ab initio phasing in macromolecular crystallography is proposed. A collaborative online game named CrowdPhase was designed, which relies on a human-powered genetic algorithm, where players control the selection mechanism during the evolutionary process. The algorithm starts from a population of ‘individuals’, each with a random genetic makeup, in this case a map prepared from a random set of phases, and tries to cause the population to evolve towards individuals with better phases based on Darwinian survival of the fittest. Players apply their pattern-recognition capabilities to evaluate the electron-density maps generated from these sets of phases and to select the fittest individuals. A user-friendly interface, a training stage and a competitive scoring system foster a network of well trained players who can guide the genetic algorithm towards better solutions from generation to generation via gameplay. CrowdPhase was applied to two synthetic low-resolution phasing puzzles and it was shown that players could successfully obtain phase sets in the 30° phase error range and corresponding molecular envelopes showing agreement with the low-resolution models. The successful preliminary studies suggest that with further development the crowdsourcing approach could fill a gap in current crystallographic methods by making it

  18. CrowdPhase: crowdsourcing the phase problem

    Energy Technology Data Exchange (ETDEWEB)

    Jorda, Julien; Sawaya, Michael R. [Institute for Genomics and Proteomics, 611 Charles Young Drive East, Los Angeles, CA 90095 (United States); Yeates, Todd O., E-mail: yeates@mbi.ucla.edu [Institute for Genomics and Proteomics, 611 Charles Young Drive East, Los Angeles, CA 90095 (United States); Molecular Biology Institute, 611 Charles Young Drive East, Los Angeles, CA 90095 (United States); University of California, 611 Charles Young Drive East, Los Angeles, CA 90095 (United States)

    2014-06-01

    The idea of attacking the phase problem by crowdsourcing is introduced. Using an interactive, multi-player, web-based system, participants work simultaneously to select phase sets that correspond to better electron-density maps in order to solve low-resolution phasing problems. The human mind innately excels at some complex tasks that are difficult to solve using computers alone. For complex problems amenable to parallelization, strategies can be developed to exploit human intelligence in a collective form: such approaches are sometimes referred to as ‘crowdsourcing’. Here, a first attempt at a crowdsourced approach for low-resolution ab initio phasing in macromolecular crystallography is proposed. A collaborative online game named CrowdPhase was designed, which relies on a human-powered genetic algorithm, where players control the selection mechanism during the evolutionary process. The algorithm starts from a population of ‘individuals’, each with a random genetic makeup, in this case a map prepared from a random set of phases, and tries to cause the population to evolve towards individuals with better phases based on Darwinian survival of the fittest. Players apply their pattern-recognition capabilities to evaluate the electron-density maps generated from these sets of phases and to select the fittest individuals. A user-friendly interface, a training stage and a competitive scoring system foster a network of well trained players who can guide the genetic algorithm towards better solutions from generation to generation via gameplay. CrowdPhase was applied to two synthetic low-resolution phasing puzzles and it was shown that players could successfully obtain phase sets in the 30° phase error range and corresponding molecular envelopes showing agreement with the low-resolution models. The successful preliminary studies suggest that with further development the crowdsourcing approach could fill a gap in current crystallographic methods by making it

  19. Comprehensive analysis of TEM methods for LiFePO4/FePO4 phase mapping: spectroscopic techniques (EFTEM, STEM-EELS) and STEM diffraction techniques (ACOM-TEM).

    Science.gov (United States)

    Mu, X; Kobler, A; Wang, D; Chakravadhanula, V S K; Schlabach, S; Szabó, D V; Norby, P; Kübel, C

    2016-11-01

    Transmission electron microscopy (TEM) has been used intensively in investigating battery materials, e.g. to obtain phase maps of partially (dis)charged (lithium) iron phosphate (LFP/FP), which is one of the most promising cathode material for next generation lithium ion (Li-ion) batteries. Due to the weak interaction between Li atoms and fast electrons, mapping of the Li distribution is not straightforward. In this work, we revisited the issue of TEM measurements of Li distribution maps for LFP/FP. Different TEM techniques, including spectroscopic techniques (energy filtered (EF)TEM in the energy range from low-loss to core-loss) and a STEM diffraction technique (automated crystal orientation mapping (ACOM)), were applied to map the lithiation of the same location in the same sample. This enabled a direct comparison of the results. The maps obtained by all methods showed excellent agreement with each other. Because of the strong difference in the imaging mechanisms, it proves the reliability of both the spectroscopic and STEM diffraction phase mapping. A comprehensive comparison of all methods is given in terms of information content, dose level, acquisition time and signal quality. The latter three are crucial for the design of in-situ experiments with beam sensitive Li-ion battery materials. Furthermore, we demonstrated the power of STEM diffraction (ACOM-STEM) providing additional crystallographic information, which can be analyzed to gain a deeper understanding of the LFP/FP interface properties such as statistical information on phase boundary orientation and misorientation between domains. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Re-evaluation of a novel approach for quantitative myocardial oedema detection by analysing tissue inhomogeneity in acute myocarditis using T2-mapping

    Energy Technology Data Exchange (ETDEWEB)

    Baessler, Bettina; Treutlein, Melanie; Maintz, David; Bunck, Alexander C. [University Hospital of Cologne, Department of Radiology, Cologne (Germany); Schaarschmidt, Frank [Leibniz Universitaet Hannover, Institute of Biostatistics, Faculty of Natural Sciences, Hannover (Germany); Stehning, Christian [Philips Research, Hamburg (Germany); Schnackenburg, Bernhard [Philips, Healthcare Germany, Hamburg (Germany); Michels, Guido [University Hospital of Cologne, Department III of Internal Medicine, Heart Centre, Cologne (Germany)

    2017-12-15

    To re-evaluate a recently suggested approach of quantifying myocardial oedema and increased tissue inhomogeneity in myocarditis by T2-mapping. Cardiac magnetic resonance data of 99 patients with myocarditis were retrospectively analysed. Thirthy healthy volunteers served as controls. T2-mapping data were acquired at 1.5 T using a gradient-spin-echo T2-mapping sequence. T2-maps were segmented according to the 16-segments AHA-model. Segmental T2-values, segmental pixel-standard deviation (SD) and the derived parameters maxT2, maxSD and madSD were analysed and compared to the established Lake Louise criteria (LLC). A re-estimation of logistic regression models revealed that all models containing an SD-parameter were superior to any model containing global myocardial T2. Using a combined cut-off of 1.8 ms for madSD + 68 ms for maxT2 resulted in a diagnostic sensitivity of 75% and specificity of 80% and showed a similar diagnostic performance compared to LLC in receiver-operating-curve analyses. Combining madSD, maxT2 and late gadolinium enhancement (LGE) in a model resulted in a superior diagnostic performance compared to LLC (sensitivity 93%, specificity 83%). The results show that the novel T2-mapping-derived parameters exhibit an additional diagnostic value over LGE with the inherent potential to overcome the current limitations of T2-mapping. (orig.)

  1. Re-evaluation of a novel approach for quantitative myocardial oedema detection by analysing tissue inhomogeneity in acute myocarditis using T2-mapping

    International Nuclear Information System (INIS)

    Baessler, Bettina; Treutlein, Melanie; Maintz, David; Bunck, Alexander C.; Schaarschmidt, Frank; Stehning, Christian; Schnackenburg, Bernhard; Michels, Guido

    2017-01-01

    To re-evaluate a recently suggested approach of quantifying myocardial oedema and increased tissue inhomogeneity in myocarditis by T2-mapping. Cardiac magnetic resonance data of 99 patients with myocarditis were retrospectively analysed. Thirthy healthy volunteers served as controls. T2-mapping data were acquired at 1.5 T using a gradient-spin-echo T2-mapping sequence. T2-maps were segmented according to the 16-segments AHA-model. Segmental T2-values, segmental pixel-standard deviation (SD) and the derived parameters maxT2, maxSD and madSD were analysed and compared to the established Lake Louise criteria (LLC). A re-estimation of logistic regression models revealed that all models containing an SD-parameter were superior to any model containing global myocardial T2. Using a combined cut-off of 1.8 ms for madSD + 68 ms for maxT2 resulted in a diagnostic sensitivity of 75% and specificity of 80% and showed a similar diagnostic performance compared to LLC in receiver-operating-curve analyses. Combining madSD, maxT2 and late gadolinium enhancement (LGE) in a model resulted in a superior diagnostic performance compared to LLC (sensitivity 93%, specificity 83%). The results show that the novel T2-mapping-derived parameters exhibit an additional diagnostic value over LGE with the inherent potential to overcome the current limitations of T2-mapping. (orig.)

  2. Polymer scaffolds with no skin-effect for tissue engineering applications fabricated by thermally induced phase separation

    Czech Academy of Sciences Publication Activity Database

    Kasoju, Naresh; Kubies, Dana; Sedlačík, Tomáš; Janoušková, Olga; Koubková, Jana; Kumorek, Marta M.; Rypáček, František

    2016-01-01

    Roč. 11, č. 1 (2016), 015002_1-015002_13 ISSN 1748-6041 R&D Projects: GA MŠk(CZ) EE2.3.30.0029; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 Keywords : tissue engineering * porous scaffolds * thermally induced phase separation Subject RIV: CE - Biochemistry Impact factor: 2.469, year: 2016

  3. Phase contrast enhanced high resolution X-ray imaging and tomography of soft tissue

    International Nuclear Information System (INIS)

    Jakubek, Jan; Granja, Carlos; Dammer, Jiri; Hanus, Robert; Holy, Tomas; Pospisil, Stanislav; Tykva, Richard; Uher, Josef; Vykydal, Zdenek

    2007-01-01

    A tabletop system for digital high resolution and high sensitivity X-ray micro-radiography has been developed for small-animal and soft-tissue imaging. The system is based on a micro-focus X-ray tube and the semiconductor hybrid position sensitive Medipix2 pixel detector. Transmission radiography imaging, conventionally based only on absorption, is enhanced by exploiting phase-shift effects induced in the X-ray beam traversing the sample. Phase contrast imaging is realized by object edge enhancement. DAQ is done by a novel fully integrated USB-based readout with online image generation. Improved signal reconstruction techniques make use of advanced statistical data analysis, enhanced beam hardening correction and direct thickness calibration of individual pixels. 2D and 3D micro-tomography images of several biological samples demonstrate the applicability of the system for biological and medical purposes including in-vivo and time dependent physiological studies in the life sciences

  4. Stochasticity in the Josephson map

    International Nuclear Information System (INIS)

    Nomura, Y.; Ichikawa, Y.H.; Filippov, A.T.

    1996-04-01

    The Josephson map describes nonlinear dynamics of systems characterized by standard map with the uniform external bias superposed. The intricate structures of the phase space portrait of the Josephson map are examined on the basis of the tangent map associated with the Josephson map. Numerical observation of the stochastic diffusion in the Josephson map is examined in comparison with the renormalized diffusion coefficient calculated by the method of characteristic function. The global stochasticity of the Josephson map occurs at the values of far smaller stochastic parameter than the case of the standard map. (author)

  5. CONSTRAINING THE MILKY WAY POTENTIAL WITH A SIX-DIMENSIONAL PHASE-SPACE MAP OF THE GD-1 STELLAR STREAM

    International Nuclear Information System (INIS)

    Koposov, Sergey E.; Rix, Hans-Walter; Hogg, David W.

    2010-01-01

    The narrow GD-1 stream of stars, spanning 60 0 on the sky at a distance of ∼10 kpc from the Sun and ∼15 kpc from the Galactic center, is presumed to be debris from a tidally disrupted star cluster that traces out a test-particle orbit in the Milky Way halo. We combine Sloan Digital Sky Survey (SDSS) photometry, USNO-B astrometry, and SDSS and Calar Alto spectroscopy to construct a complete, empirical six-dimensional (6D) phase-space map of the stream. We find that an eccentric orbit in a flattened isothermal potential describes this phase-space map well. Even after marginalizing over the stream orbital parameters and the distance from the Sun to the Galactic center, the orbital fit to GD-1 places strong constraints on the circular velocity at the Sun's radius V c = 224 ± 13 km s -1 and total potential flattening q Φ = 0.87 +0.07 -0.04 . When we drop any informative priors on V c , the GD-1 constraint becomes V c = 221 ± 18 km s -1 . Our 6D map of GD-1, therefore, yields the best current constraint on V c and the only strong constraint on q Φ at Galactocentric radii near R ∼ 15 kpc. Much, if not all, of the total potential flattening may be attributed to the mass in the stellar disk, so the GD-1 constraints on the flattening of the halo itself are weak: q Φ,halo > 0.89 at 90% confidence. The greatest uncertainty in the 6D map and the orbital analysis stems from the photometric distances, which will be obviated by GAIA.

  6. Determination of glutamate dehydrogenase activity and its kinetics in mouse tissues using metabolic mapping (quantitative enzyme histochemistry).

    Science.gov (United States)

    Botman, Dennis; Tigchelaar, Wikky; Van Noorden, Cornelis J F

    2014-11-01

    Glutamate dehydrogenase (GDH) catalyses the reversible conversion of glutamate into α-ketoglutarate with the concomitant reduction of NAD(P)(+) to NAD(P)H or vice versa. GDH activity is subject to complex allosteric regulation including substrate inhibition. To determine GDH kinetics in situ, we assessed the effects of various glutamate concentrations in combination with either the coenzyme NAD(+) or NADP(+) on GDH activity in mouse liver cryostat sections using metabolic mapping. NAD(+)-dependent GDH V(max) was 2.5-fold higher than NADP(+)-dependent V(max), whereas the K(m) was similar, 1.92 mM versus 1.66 mM, when NAD(+) or NADP(+) was used, respectively. With either coenzyme, V(max) was determined at 10 mM glutamate and substrate inhibition was observed at higher glutamate concentrations with a K(i) of 12.2 and 3.95 for NAD(+) and NADP(+) used as coenzyme, respectively. NAD(+)- and NADP(+)-dependent GDH activities were examined in various mouse tissues. GDH activity was highest in liver and much lower in other tissues. In all tissues, the highest activity was found when NAD(+) was used as a coenzyme. In conclusion, GDH activity in mice is highest in the liver with NAD(+) as a coenzyme and highest GDH activity was determined at a glutamate concentration of 10 mM. © The Author(s) 2014.

  7. Association of intraoperative tissue oxygenation with suspected risk factors for tissue hypoxia.

    Science.gov (United States)

    Spruit, R J; Schwarte, L A; Hakenberg, O W; Scheeren, T W L

    2013-10-01

    Tissue hypoxia may cause organ dysfunction, but not much is known about tissue oxygenation in the intraoperative setting. We studied microcirculatory tissue oxygen saturation (StO₂) to determine representative values for anesthetized patients undergoing urological surgery and to test the hypothesis that StO₂ is associated with known perioperative risk factors for morbidity and mortality, conventionally monitored variables, and hypotension requiring norepinephrine. Using near-infrared spectroscopy, we measured StO₂ on the thenar eminence in 160 patients undergoing open urological surgery under general anesthesia (FiO2 0.35-0.4), and calculated its correlations with age, risk level for general perioperative complications and mortality (high if age ≥70 and procedure is radical cystectomy), mean arterial pressure (MAP), hemoglobin concentration (Hb), central venous oxygen saturation (ScvO₂), and norepinephrine use. The time averaged StO₂ was 86 ± 6 % (mean ± SD). In the multivariate analysis, Hb [standardized coefficient (SC) 0.21, p = 0.003], ScvO₂ (SC 0.53, p SStO₂ was partly dependent on MAP only when this was below 65 mmHg (lowest MAP SC 0.20, p = 0.006, MAP area under the curve <65 mmHg SC 0.03, p = 0.02). Finally, StO₂ was slightly lower in patients requiring norepinephrine (85 ± 6 vs. 89 ± 6 %, p = 0.001). Intraoperative StO₂ in urological patients was comparable to that of healthy volunteers breathing room air as reported in the literature and correlated with known perioperative risk factors. Further research should investigate its association with outcome and the effect of interventions aimed at optimizing StO₂.

  8. Geometric phases in discrete dynamical systems

    Energy Technology Data Exchange (ETDEWEB)

    Cartwright, Julyan H.E., E-mail: julyan.cartwright@csic.es [Instituto Andaluz de Ciencias de la Tierra, CSIC–Universidad de Granada, E-18100 Armilla, Granada (Spain); Instituto Carlos I de Física Teórica y Computacional, Universidad de Granada, E-18071 Granada (Spain); Piro, Nicolas, E-mail: nicolas.piro@epfl.ch [École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne (Switzerland); Piro, Oreste, E-mail: piro@imedea.uib-csic.es [Departamento de Física, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain); Tuval, Idan, E-mail: ituval@imedea.uib-csic.es [Mediterranean Institute for Advanced Studies, CSIC–Universitat de les Illes Balears, E-07190 Mallorca (Spain)

    2016-10-14

    In order to study the behaviour of discrete dynamical systems under adiabatic cyclic variations of their parameters, we consider discrete versions of adiabatically-rotated rotators. Parallelling the studies in continuous systems, we generalize the concept of geometric phase to discrete dynamics and investigate its presence in these rotators. For the rotated sine circle map, we demonstrate an analytical relationship between the geometric phase and the rotation number of the system. For the discrete version of the rotated rotator considered by Berry, the rotated standard map, we further explore this connection as well as the role of the geometric phase at the onset of chaos. Further into the chaotic regime, we show that the geometric phase is also related to the diffusive behaviour of the dynamical variables and the Lyapunov exponent. - Highlights: • We extend the concept of geometric phase to maps. • For the rotated sine circle map, we demonstrate an analytical relationship between the geometric phase and the rotation number. • For the rotated standard map, we explore the role of the geometric phase at the onset of chaos. • We show that the geometric phase is related to the diffusive behaviour of the dynamical variables and the Lyapunov exponent.

  9. A two-phase flow regime map for a MAPLE-type nuclear research reactor fuel channel: Effect of hexagonal finned bundle

    International Nuclear Information System (INIS)

    Harvel, G.D.; Chang, J.S.

    1997-01-01

    A two-phase flow regime map is developed experimentally and theoretically for a vertical hexagonal flow channel with and without a 36-finned rod hexagonal bundle. This type of flow channel is of interest to MAPLE-type nuclear research reactors. The flow regime maps are determined by visual observations and observation of waveforms shown by a capacitance-type void fraction meter. The experimental results show that the inclusion of the finned hexagonal bundle shifts the flow regime transition boundaries toward higher water flow rates. Existing flow regime maps based on pipe flow require slight modifications when applied to the hexagonal flow channel with and without a MAPLE-type finned hexagonal bundle. The proposed theoretical model agrees well with experimental results

  10. Background field removal using a region adaptive kernel for quantitative susceptibility mapping of human brain.

    Science.gov (United States)

    Fang, Jinsheng; Bao, Lijun; Li, Xu; van Zijl, Peter C M; Chen, Zhong

    2017-08-01

    Background field removal is an important MR phase preprocessing step for quantitative susceptibility mapping (QSM). It separates the local field induced by tissue magnetic susceptibility sources from the background field generated by sources outside a region of interest, e.g. brain, such as air-tissue interface. In the vicinity of air-tissue boundary, e.g. skull and paranasal sinuses, where large susceptibility variations exist, present background field removal methods are usually insufficient and these regions often need to be excluded by brain mask erosion at the expense of losing information of local field and thus susceptibility measures in these regions. In this paper, we propose an extension to the variable-kernel sophisticated harmonic artifact reduction for phase data (V-SHARP) background field removal method using a region adaptive kernel (R-SHARP), in which a scalable spherical Gaussian kernel (SGK) is employed with its kernel radius and weights adjustable according to an energy "functional" reflecting the magnitude of field variation. Such an energy functional is defined in terms of a contour and two fitting functions incorporating regularization terms, from which a curve evolution model in level set formation is derived for energy minimization. We utilize it to detect regions of with a large field gradient caused by strong susceptibility variation. In such regions, the SGK will have a small radius and high weight at the sphere center in a manner adaptive to the voxel energy of the field perturbation. Using the proposed method, the background field generated from external sources can be effectively removed to get a more accurate estimation of the local field and thus of the QSM dipole inversion to map local tissue susceptibility sources. Numerical simulation, phantom and in vivo human brain data demonstrate improved performance of R-SHARP compared to V-SHARP and RESHARP (regularization enabled SHARP) methods, even when the whole paranasal sinus regions

  11. Association between increased epicardial adipose tissue volume and coronary plaque composition.

    Science.gov (United States)

    Yamashita, Kennosuke; Yamamoto, Myong Hwa; Ebara, Seitarou; Okabe, Toshitaka; Saito, Shigeo; Hoshimoto, Koichi; Yakushiji, Tadayuki; Isomura, Naoei; Araki, Hiroshi; Obara, Chiaki; Ochiai, Masahiko

    2014-09-01

    To assess the relationship between epicardial adipose tissue volume (EATV) and plaque vulnerability in significant coronary stenosis using a 40-MHz intravascular ultrasound (IVUS) imaging system (iMap-IVUS), we analyzed 130 consecutive patients with coronary stenosis who underwent dual-source computed tomography (CT) and cardiac catheterization. Culprit lesions were imaged by iMap-IVUS before stenting. The iMAP-IVUS system classified coronary plaque components as fibrous, lipid, necrotic, or calcified tissue, based on the radiofrequency spectrum. Epicardial adipose tissue was measured as the tissue ranging from -190 to -30 Hounsfield units. EATV, calculated as the sum of the fat areas on short-axis images, was 85.0 ± 34.0 cm(3). There was a positive correlation between EATV and the percentage of necrotic plaque tissue (R (2) = 0.34, P EATV and the percentage of fibrous tissue (R (2) = 0.24, P EATV (β = 0.14, P = 0.02) were independently associated with the percentage of necrotic plaque tissue. An increase in EATV was associated with the development of coronary atherosclerosis and, potentially, with the most dangerous type of plaque.

  12. Visualization of dielectric constant-electric field-temperature phase maps for imprinted relaxor ferroelectric thin films

    International Nuclear Information System (INIS)

    Frederick, J. C.; Kim, T. H.; Maeng, W.; Brewer, A. A.; Podkaminer, J. P.; Saenrang, W.; Vaithyanathan, V.; Schlom, D. G.; Li, F.; Chen, L.-Q.; Trolier-McKinstry, S.; Rzchowski, M. S.; Eom, C. B.

    2016-01-01

    The dielectric phase transition behavior of imprinted lead magnesium niobate–lead titanate relaxor ferroelectric thin films was mapped as a function of temperature and dc bias. To compensate for the presence of internal fields, an external electric bias was applied while measuring dielectric responses. The constructed three-dimensional dielectric maps provide insight into the dielectric behaviors of relaxor ferroelectric films as well as the temperature stability of the imprint. The transition temperature and diffuseness of the dielectric response correlate with crystallographic disorder resulting from strain and defects in the films grown on strontium titanate and silicon substrates; the latter was shown to induce a greater degree of disorder in the film as well as a dielectric response lower in magnitude and more diffuse in nature over the same temperature region. Strong and stable imprint was exhibited in both films and can be utilized to enhance the operational stability of piezoelectric devices through domain self-poling.

  13. Decomposing the Hounsfield unit: probabilistic segmentation of brain tissue in computed tomography.

    Science.gov (United States)

    Kemmling, A; Wersching, H; Berger, K; Knecht, S; Groden, C; Nölte, I

    2012-03-01

    The aim of this study was to present and evaluate a standardized technique for brain segmentation of cranial computed tomography (CT) using probabilistic partial volume tissue maps based on a database of high resolution T1 magnetic resonance images (MRI). Probabilistic tissue maps of white matter (WM), gray matter (GM) and cerebrospinal fluid (CSF) were derived from 600 normal brain MRIs (3.0 Tesla, T1-3D-turbo-field-echo) of 2 large community-based population studies (BiDirect and SEARCH Health studies). After partial tissue segmentation (FAST 4.0), MR images were linearly registered to MNI-152 standard space (FLIRT 5.5) with non-linear refinement (FNIRT 1.0) to obtain non-binary probabilistic volume images for each tissue class which were subsequently used for CT segmentation. From 150 normal cerebral CT scans a customized reference image in standard space was constructed with iterative non-linear registration to MNI-152 space. The inverse warp of tissue-specific probability maps to CT space (MNI-152 to individual CT) was used to decompose a CT image into tissue specific components (GM, WM, CSF). Potential benefits and utility of this novel approach with regard to unsupervised quantification of CT images and possible visual enhancement are addressed. Illustrative examples of tissue segmentation in different pathological cases including perfusion CT are presented. Automated tissue segmentation of cranial CT images using highly refined tissue probability maps derived from high resolution MR images is feasible. Potential applications include automated quantification of WM in leukoaraiosis, CSF in hydrocephalic patients, GM in neurodegeneration and ischemia and perfusion maps with separate assessment of GM and WM.

  14. Three-dimensional micro-scale strain mapping in living biological soft tissues.

    Science.gov (United States)

    Moo, Eng Kuan; Sibole, Scott C; Han, Sang Kuy; Herzog, Walter

    2018-04-01

    Non-invasive characterization of the mechanical micro-environment surrounding cells in biological tissues at multiple length scales is important for the understanding of the role of mechanics in regulating the biosynthesis and phenotype of cells. However, there is a lack of imaging methods that allow for characterization of the cell micro-environment in three-dimensional (3D) space. The aims of this study were (i) to develop a multi-photon laser microscopy protocol capable of imprinting 3D grid lines onto living tissue at a high spatial resolution, and (ii) to develop image processing software capable of analyzing the resulting microscopic images and performing high resolution 3D strain analyses. Using articular cartilage as the biological tissue of interest, we present a novel two-photon excitation imaging technique for measuring the internal 3D kinematics in intact cartilage at sub-micrometer resolution, spanning length scales from the tissue to the cell level. Using custom image processing software, we provide accurate and robust 3D micro-strain analysis that allows for detailed qualitative and quantitative assessment of the 3D tissue kinematics. This novel technique preserves tissue structural integrity post-scanning, therefore allowing for multiple strain measurements at different time points in the same specimen. The proposed technique is versatile and opens doors for experimental and theoretical investigations on the relationship between tissue deformation and cell biosynthesis. Studies of this nature may enhance our understanding of the mechanisms underlying cell mechano-transduction, and thus, adaptation and degeneration of soft connective tissues. We presented a novel two-photon excitation imaging technique for measuring the internal 3D kinematics in intact cartilage at sub-micrometer resolution, spanning from tissue length scale to cellular length scale. Using a custom image processing software (lsmgridtrack), we provide accurate and robust micro

  15. Improved cancer risk stratification and diagnosis via quantitative phase microscopy (Conference Presentation)

    Science.gov (United States)

    Liu, Yang; Uttam, Shikhar; Pham, Hoa V.; Hartman, Douglas J.

    2017-02-01

    Pathology remains the gold standard for cancer diagnosis and in some cases prognosis, in which trained pathologists examine abnormality in tissue architecture and cell morphology characteristic of cancer cells with a bright-field microscope. The limited resolution of conventional microscope can result in intra-observer variation, missed early-stage cancers, and indeterminate cases that often result in unnecessary invasive procedures in the absence of cancer. Assessment of nanoscale structural characteristics via quantitative phase represents a promising strategy for identifying pre-cancerous or cancerous cells, due to its nanoscale sensitivity to optical path length, simple sample preparation (i.e., label-free) and low cost. I will present the development of quantitative phase microscopy system in transmission and reflection configuration to detect the structural changes in nuclear architecture, not be easily identifiable by conventional pathology. Specifically, we will present the use of transmission-mode quantitative phase imaging to improve diagnostic accuracy of urine cytology and the nuclear dry mass is progressively correlate with negative, atypical, suspicious and positive cytological diagnosis. In a second application, we will present the use of reflection-mode quantitative phase microscopy for depth-resolved nanoscale nuclear architecture mapping (nanoNAM) of clinically prepared formalin-fixed, paraffin-embedded tissue sections. We demonstrated that the quantitative phase microscopy system detects a gradual increase in the density alteration of nuclear architecture during malignant transformation in animal models of colon carcinogenesis and in human patients with ulcerative colitis, even in tissue that appears histologically normal according to pathologists. We evaluated the ability of nanoNAM to predict "future" cancer progression in patients with ulcerative colitis.

  16. Analysis of a new phase and height algorithm in phase measurement profilometry

    Science.gov (United States)

    Bian, Xintian; Zuo, Fen; Cheng, Ju

    2018-04-01

    Traditional phase measurement profilometry adopts divergent illumination to obtain the height distribution of a measured object accurately. However, the mapping relation between reference plane coordinates and phase distribution must be calculated before measurement. Data are then stored in a computer in the form of a data sheet for standby applications. This study improved the distribution of projected fringes and deducted the phase-height mapping algorithm when the two pupils of the projection and imaging systems are of unequal heights and when the projection and imaging axes are on different planes. With the algorithm, calculating the mapping relation between reference plane coordinates and phase distribution prior to measurement is unnecessary. Thus, the measurement process is simplified, and the construction of an experimental system is made easy. Computer simulation and experimental results confirm the effectiveness of the method.

  17. Real-time optoacoustic monitoring of temperature in tissues

    International Nuclear Information System (INIS)

    Larina, Irina V; Larin, Kirill V; Esenaliev, Rinat O

    2005-01-01

    To improve the safety and efficacy of thermal therapy, it is necessary to map tissue temperature in real time with submillimetre spatial resolution. Accurate temperature maps may provide the necessary control of the boundaries of the heated regions and minimize thermal damage to surrounding normal tissues. Current imaging modalities fail to monitor tissue temperature in real time with high resolution and accuracy. We investigated a non-invasive optoacoustic method for accurate, real-time monitoring of tissue temperature during thermotherapy. In this study, we induced temperature gradients in tissue and tissue-like samples and monitored the temperature distribution using the optoacoustic technique. The fundamental harmonic of a Q-switched Nd : YAG laser (λ = 1064 nm) was used for optoacoustic wave generation and probing of tissue temperature. The tissue temperature was also monitored with a multi-sensor temperature probe inserted in the samples. Good agreement between optoacoustically measured and actual tissue temperatures was obtained. The accuracy of temperature monitoring was better than 1 0 C, while the spatial resolution was about 1 mm. These data suggest that the optoacoustic technique has the potential to be used for non-invasive, real-time temperature monitoring during thermotherapy

  18. Impact of tissue atrophy on high-pass filtered MRI signal phase-based assessment in large-scale group-comparison studies: A simulation study

    Science.gov (United States)

    Schweser, Ferdinand; Dwyer, Michael G.; Deistung, Andreas; Reichenbach, Jürgen R.; Zivadinov, Robert

    2013-10-01

    The assessment of abnormal accumulation of tissue iron in the basal ganglia nuclei and in white matter plaques using the gradient echo magnetic resonance signal phase has become a research focus in many neurodegenerative diseases such as multiple sclerosis or Parkinson’s disease. A common and natural approach is to calculate the mean high-pass-filtered phase of previously delineated brain structures. Unfortunately, the interpretation of such an analysis requires caution: in this paper we demonstrate that regional gray matter atrophy, which is concomitant with many neurodegenerative diseases, may itself directly result in a phase shift seemingly indicative of increased iron concentration even without any real change in the tissue iron concentration. Although this effect is relatively small results of large-scale group comparisons may be driven by anatomical changes rather than by changes of the iron concentration.

  19. Covariance and correlation estimation in electron-density maps.

    Science.gov (United States)

    Altomare, Angela; Cuocci, Corrado; Giacovazzo, Carmelo; Moliterni, Anna; Rizzi, Rosanna

    2012-03-01

    Quite recently two papers have been published [Giacovazzo & Mazzone (2011). Acta Cryst. A67, 210-218; Giacovazzo et al. (2011). Acta Cryst. A67, 368-382] which calculate the variance in any point of an electron-density map at any stage of the phasing process. The main aim of the papers was to associate a standard deviation to each pixel of the map, in order to obtain a better estimate of the map reliability. This paper deals with the covariance estimate between points of an electron-density map in any space group, centrosymmetric or non-centrosymmetric, no matter the correlation between the model and target structures. The aim is as follows: to verify if the electron density in one point of the map is amplified or depressed as an effect of the electron density in one or more other points of the map. High values of the covariances are usually connected with undesired features of the map. The phases are the primitive random variables of our probabilistic model; the covariance changes with the quality of the model and therefore with the quality of the phases. The conclusive formulas show that the covariance is also influenced by the Patterson map. Uncertainty on measurements may influence the covariance, particularly in the final stages of the structure refinement; a general formula is obtained taking into account both phase and measurement uncertainty, valid at any stage of the crystal structure solution.

  20. Disrupted G1 to S phase clearance via cyclin signaling impairs liver tissue repair in thioacetamide-treated type 1 diabetic rats

    International Nuclear Information System (INIS)

    Devi, Sachin S.; Mehendale, Harihara M.

    2005-01-01

    Previously we reported that a nonlethal dose of thioacetamide (TA, 300 mg/kg) causes 90% mortality in type 1 diabetic (DB) rats because of irreversible acute liver injury owing to inhibited hepatic tissue repair, primarily due to blockage of G 0 to S phase progression of cell division cycle. On the other hand, DB rats receiving 30 mg TA/kg exhibited equal initial liver injury and delayed tissue repair compared to nondiabetic (NDB) rats receiving 300 mg TA/kg, resulting in a delay in recovery from liver injury and survival. The objective of the present study was to test the hypothesis that impaired cyclin-regulated progression of G 1 to S phase of the cell cycle may explain inhibited liver tissue repair, hepatic failure, and death, contrasted with delayed liver tissue repair but survival observed in the DB rats receiving 300 in contrast to 30 mg TA/kg. In the TA-treated NDB rats sustained MAPKs and cyclin expression resulted in higher phosphorylation of retinoblastoma (pRb), explaining prompt tissue repair and survival. In contrast, DB rats receiving the same dose of TA (300 mg/kg) exhibited suppressed MAPKs and cyclin expression that led to inhibition of pRb, inhibited tissue repair, and death. On the other hand, DB rats receiving 30 mg TA/kg exhibited delayed up regulation of MAPK signaling that delayed the expression of CD1 and pRb, explaining delayed stimulation of tissue repair observed in this group. In conclusion, the hepatotoxicant TA has a dose-dependent adverse effect on cyclin-regulated pRb signaling: the lower dose causes a recoverable delay, whereas the higher dose inhibits it with corresponding effect on the ultimate outcomes on hepatic tissue repair; this dose-dependent adverse effect is substantially shifted to the left of the dose response curve in diabetes

  1. Rotation number of integrable symplectic mappings of the plane

    Energy Technology Data Exchange (ETDEWEB)

    Zolkin, Timofey [Fermilab; Nagaitsev, Sergei [Fermilab; Danilov, Viatcheslav [Oak Ridge

    2017-04-11

    Symplectic mappings are discrete-time analogs of Hamiltonian systems. They appear in many areas of physics, including, for example, accelerators, plasma, and fluids. Integrable mappings, a subclass of symplectic mappings, are equivalent to a Twist map, with a rotation number, constant along the phase trajectory. In this letter, we propose a succinct expression to determine the rotation number and present two examples. Similar to the period of the bounded motion in Hamiltonian systems, the rotation number is the most fundamental property of integrable maps and it provides a way to analyze the phase-space dynamics.

  2. Point-of-care instrument for monitoring tissue health during skin graft repair

    Science.gov (United States)

    Gurjar, R. S.; Seetamraju, M.; Zhang, J.; Feinberg, S. E.; Wolf, D. E.

    2011-06-01

    We have developed the necessary theoretical framework and the basic instrumental design parameters to enable mapping of subsurface blood dynamics and tissue oxygenation for patients undergoing skin graft procedures. This analysis forms the basis for developing a simple patch geometry, which can be used to map by diffuse optical techniques blood flow velocity and tissue oxygenation as a function of depth in subsurface tissue.skin graft, diffuse correlation analysis, oxygen saturation.

  3. Determination of catechins and catechin gallates in tissues by liquid chromatography with coulometric array detection and selective solid phase extraction.

    Science.gov (United States)

    Chu, Kai On; Wang, Chi Chiu; Chu, Ching Yan; Rogers, Michael Scott; Choy, Kwong Wai; Pang, Chi Pui

    2004-10-25

    Catechins levels in organ tissues, particularly liver, determined by published methods are unexpectedly low, probably due to the release of oxidative enzymes, metal ions and reactive metabolites from tissue cells during homogenization and to the pro-oxidant effects of ascorbic acid during sample processing in the presence of metal ions. We describe a new method for simultaneous analysis of eight catechins in tissue: (+)-catechin (C), (-)-epicatechin (EC), (-)-gallocatechin (GC), (-)-epigallocatechin (EGC), (-)-catechin gallate (CG), (-)-epicatechin gallate (ECG), (-)-gallocatechin gallate (GCG) and (-)-epigallocatechin gallate (EGCG) (Fig. 1). The new extraction procedure utilized a methanol/ethylacetate/dithionite (2:1:3) mixture during homogenization for simultaneous enzyme precipitation and antioxidant protection. Selective solid phase extraction was used to remove most interfering bio-matrices. Reversed phase HPLC with CoulArray detection was used to determine the eight catechins simultaneously within 25 min. Good linearity (>0.9922) was obtained in the range 20-4000 ng/g. The coefficients of variance (CV) were less than 5%. Absolute recovery ranged from 62 to 96%, accuracy 92.5 +/- 4.5 to 104.9 +/- 6%. The detection limit was 5 ng/g. This method is capable for determining catechins in rat tissues of liver, brain, spleen, and kidney. The method is robust, reproducible, with high recovery, and has been validated for both in vitro and in vivo sample analysis.

  4. Axon diameter mapping in crossing fibers with diffusion MRI

    DEFF Research Database (Denmark)

    Zhang, Hui; Dyrby, Tim B; Alexander, Daniel C

    2011-01-01

    This paper proposes a technique for a previously unaddressed problem, namely, mapping axon diameter in crossing fiber regions, using diffusion MRI. Direct measurement of tissue microstructure of this kind using diffusion MRI offers a new class of biomarkers that give more specific information about...... tissue than measures derived from diffusion tensor imaging. Most existing techniques for axon diameter mapping assume a single axon orientation in the tissue model, which limits their application to only the most coherently oriented brain white matter, such as the corpus callosum, where the single...... model to enable axon diameter mapping in voxels with crossing fibers. We show in simulation that the technique can provide robust axon diameter estimates in a two-fiber crossing with the crossing angle as small as 45 degrees. Using ex vivo imaging data, we further demonstrate the feasibility...

  5. Quality Measures in Pre-Analytical Phase of Tissue Processing: Understanding Its Value in Histopathology.

    Science.gov (United States)

    Rao, Shalinee; Masilamani, Suresh; Sundaram, Sandhya; Duvuru, Prathiba; Swaminathan, Rajendiran

    2016-01-01

    Quality monitoring in histopathology unit is categorized into three phases, pre-analytical, analytical and post-analytical, to cover various steps in the entire test cycle. Review of literature on quality evaluation studies pertaining to histopathology revealed that earlier reports were mainly focused on analytical aspects with limited studies on assessment of pre-analytical phase. Pre-analytical phase encompasses several processing steps and handling of specimen/sample by multiple individuals, thus allowing enough scope for errors. Due to its critical nature and limited studies in the past to assess quality in pre-analytical phase, it deserves more attention. This study was undertaken to analyse and assess the quality parameters in pre-analytical phase in a histopathology laboratory. This was a retrospective study done on pre-analytical parameters in histopathology laboratory of a tertiary care centre on 18,626 tissue specimens received in 34 months. Registers and records were checked for efficiency and errors for pre-analytical quality variables: specimen identification, specimen in appropriate fixatives, lost specimens, daily internal quality control performance on staining, performance in inter-laboratory quality assessment program {External quality assurance program (EQAS)} and evaluation of internal non-conformities (NC) for other errors. The study revealed incorrect specimen labelling in 0.04%, 0.01% and 0.01% in 2007, 2008 and 2009 respectively. About 0.04%, 0.07% and 0.18% specimens were not sent in fixatives in 2007, 2008 and 2009 respectively. There was no incidence of specimen lost. A total of 113 non-conformities were identified out of which 92.9% belonged to the pre-analytical phase. The predominant NC (any deviation from normal standard which may generate an error and result in compromising with quality standards) identified was wrong labelling of slides. Performance in EQAS for pre-analytical phase was satisfactory in 6 of 9 cycles. A low incidence

  6. Real-Time Vision-Based Stiffness Mapping †.

    Science.gov (United States)

    Faragasso, Angela; Bimbo, João; Stilli, Agostino; Wurdemann, Helge Arne; Althoefer, Kaspar; Asama, Hajime

    2018-04-26

    This paper presents new findings concerning a hand-held stiffness probe for the medical diagnosis of abnormalities during palpation of soft-tissue. Palpation is recognized by the medical community as an essential and low-cost method to detect and diagnose disease in soft-tissue. However, differences are often subtle and clinicians need to train for many years before they can conduct a reliable diagnosis. The probe presented here fills this gap providing a means to easily obtain stiffness values of soft tissue during a palpation procedure. Our stiffness sensor is equipped with a multi degree of freedom (DoF) Aurora magnetic tracker, allowing us to track and record the 3D position of the probe whilst examining a tissue area, and generate a 3D stiffness map in real-time. The stiffness probe was integrated in a robotic arm and tested in an artificial environment representing a good model of soft tissue organs; the results show that the sensor can accurately measure and map the stiffness of a silicon phantom embedded with areas of varying stiffness.

  7. Real-Time Vision-Based Stiffness Mapping

    Directory of Open Access Journals (Sweden)

    Angela Faragasso

    2018-04-01

    Full Text Available This paper presents new findings concerning a hand-held stiffness probe for the medical diagnosis of abnormalities during palpation of soft-tissue. Palpation is recognized by the medical community as an essential and low-cost method to detect and diagnose disease in soft-tissue. However, differences are often subtle and clinicians need to train for many years before they can conduct a reliable diagnosis. The probe presented here fills this gap providing a means to easily obtain stiffness values of soft tissue during a palpation procedure. Our stiffness sensor is equipped with a multi degree of freedom (DoF Aurora magnetic tracker, allowing us to track and record the 3D position of the probe whilst examining a tissue area, and generate a 3D stiffness map in real-time. The stiffness probe was integrated in a robotic arm and tested in an artificial environment representing a good model of soft tissue organs; the results show that the sensor can accurately measure and map the stiffness of a silicon phantom embedded with areas of varying stiffness.

  8. From symplectic integrator to Poincare map: Spline expansion of a map generator in Cartesian coordinates

    International Nuclear Information System (INIS)

    Warnock, R.L.; Ellison, J.A.; Univ. of New Mexico, Albuquerque, NM

    1997-08-01

    Data from orbits of a symplectic integrator can be interpolated so as to construct an approximation to the generating function of a Poincare map. The time required to compute an orbit of the symplectic map induced by the generator can be much less than the time to follow the same orbit by symplectic integration. The construction has been carried out previously for full-turn maps of large particle accelerators, and a big saving in time (for instance a factor of 60) has been demonstrated. A shortcoming of the work to date arose from the use of canonical polar coordinates, which precluded map construction in small regions of phase space near coordinate singularities. This paper shows that Cartesian coordinates can also be used, thus avoiding singularities. The generator is represented in a basis of tensor product B-splines. Under weak conditions the spline expansion converges uniformly as the mesh is refined, approaching the exact generator of the Poincare map as defined by the symplectic integrator, in some parallelepiped of phase space centered at the origin

  9. The role of micro-NRA and micro-PIXE in carbon mapping of organic tissues

    International Nuclear Information System (INIS)

    Niekraszewicz, L.A.B.; Souza, C.T. de; Stori, E.M.; Jobim, P.F.C.; Amaral, L.; Dias, J.F.

    2015-01-01

    This study reports the work developed in the Ion Implantation Laboratory (Porto Alegre, RS, Brazil) in order to implement the micro-NRA technique for the study of light elements in organic tissues. In particular, the work was focused on nuclear reactions employing protons and alphas with carbon. The (p,p) resonances at 0.475 and 1.734 were investigated. The (α,α) resonance at 4.265 MeV was studied as well. The results indicate that the yields for the 0.475 and 1.734 MeV resonances are similar. Elemental maps of different structures obtained with the micro-NRA technique using the 1.734 MeV resonance were compared with those obtained with micro-PIXE employing a SDD detector equipped with an ultra-thin window. The results show that the use of micro-NRA for carbon at 1.734 MeV resonance provides good results in some cases at the expense of longer beam times. On the other hand, micro-PIXE provides enhanced yields but is limited to surface analysis since soft X-rays are greatly attenuated by matter

  10. Effect of Phase-Encoding Reduction on Geometric Distortion and BOLD Signal Changes in fMRI

    Directory of Open Access Journals (Sweden)

    Golestan karami

    2013-03-01

    Full Text Available Introduction Echo-planar imaging (EPI is a group of fast data acquisition methods commonly used in fMRI studies. It acquires multiple image lines in k-space after a single excitation, which leads to a very short scan time. A well-known problem with EPI is that it is more sensitive to distortions due to the used encoding scheme. Source of distortion is inhomogeneity in the static B0 field that causes more geometric distortion in phase encoding direction. This inhomogeneity is induced mainly by the magnetic susceptibility differences between various structures within the object placed inside the scanner, often at air-tissue or bone-tissue interfaces. Methods of reducing EPI distortion are mainly based on decreasing steps of the phase encoding. Reducing steps of phase encoding can be applied by reducing field of view, slice thickness, and/or the use of parallel acquisition technique. Materials and Methods We obtained three data acquisitions with different FOVs including: conventional low resolution, conventional high resolution, and zoomed high resolution EPIs. Moreover we used SENSE technique for phase encoding reduction. All experiments were carried out on three Tesla scanners (Siemens, TIM, and Germany equipped with 12 channel head coil. Ten subjects participated in the experiments. Results The data were processed by FSL software and were evaluated by ANOVA. Distortion was assessed by obtaining low displacement voxels map, and calculated from a field map image. Conclusion We showed that image distortion can be reduced by decreasing slice thickness and phase encoding steps. Distortion reduction in zoomed technique resulted the lowest level, but at the cost of signal-to-noise loss. Moreover, the SENSE technique was shown to decrease the amount of image distortion, efficiently.

  11. Mapping photothermally induced gene expression in living cells and tissues by nanorod-locked nucleic acid complexes.

    Science.gov (United States)

    Riahi, Reza; Wang, Shue; Long, Min; Li, Na; Chiou, Pei-Yu; Zhang, Donna D; Wong, Pak Kin

    2014-04-22

    The photothermal effect of plasmonic nanostructures has numerous applications, such as cancer therapy, photonic gene circuit, large cargo delivery, and nanostructure-enhanced laser tweezers. The photothermal operation can also induce unwanted physical and biochemical effects, which potentially alter the cell behaviors. However, there is a lack of techniques for characterizing the dynamic cell responses near the site of photothermal operation with high spatiotemporal resolution. In this work, we show that the incorporation of locked nucleic acid probes with gold nanorods allows photothermal manipulation and real-time monitoring of gene expression near the area of irradiation in living cells and animal tissues. The multimodal gold nanorod serves as an endocytic delivery reagent to transport the probes into the cells, a fluorescence quencher and a binding competitor to detect intracellular mRNA, and a plasmonic photothermal transducer to induce cell ablation. We demonstrate the ability of the gold nanorod-locked nucleic acid complex for detecting the spatiotemporal gene expression in viable cells and tissues and inducing photothermal ablation of single cells. Using the gold nanorod-locked nucleic acid complex, we systematically characterize the dynamic cellular heat shock responses near the site of photothermal operation. The gold nanorod-locked nucleic acid complex enables mapping of intracellular gene expressions and analyzes the photothermal effects of nanostructures toward various biomedical applications.

  12. Absolute phase map recovery of two fringe patterns with flexible selection of fringe wavelengths.

    Science.gov (United States)

    Long, Jiale; Xi, Jiangtao; Zhu, Ming; Cheng, Wenqing; Cheng, Rui; Li, Zhongwei; Shi, Yusheng

    2014-03-20

    A novel approach is proposed to unwrap the phase maps of two fringe patterns in fringe pattern projection-based profilometry. In contrast to existing techniques, where spatial frequencies (i.e., the number of fringes on a pattern) of the two fringe patterns must be integers and coprime, the proposed method is applicable for any two fringe patterns with different fringe wavelengths (i.e., the number of pixels in a fringe) and thus provides more flexibility in the use of fringe patterns. Moreover, compared to the existing techniques, the proposed method is simpler in its implementation and has better antierror capability. Theoretical analysis and experiment results are presented to confirm the effectiveness of the proposed method.

  13. Re-evaluation of a novel approach for quantitative myocardial oedema detection by analysing tissue inhomogeneity in acute myocarditis using T2-mapping.

    Science.gov (United States)

    Baeßler, Bettina; Schaarschmidt, Frank; Treutlein, Melanie; Stehning, Christian; Schnackenburg, Bernhard; Michels, Guido; Maintz, David; Bunck, Alexander C

    2017-12-01

    To re-evaluate a recently suggested approach of quantifying myocardial oedema and increased tissue inhomogeneity in myocarditis by T2-mapping. Cardiac magnetic resonance data of 99 patients with myocarditis were retrospectively analysed. Thirthy healthy volunteers served as controls. T2-mapping data were acquired at 1.5 T using a gradient-spin-echo T2-mapping sequence. T2-maps were segmented according to the 16-segments AHA-model. Segmental T2-values, segmental pixel-standard deviation (SD) and the derived parameters maxT2, maxSD and madSD were analysed and compared to the established Lake Louise criteria (LLC). A re-estimation of logistic regression models revealed that all models containing an SD-parameter were superior to any model containing global myocardial T2. Using a combined cut-off of 1.8 ms for madSD + 68 ms for maxT2 resulted in a diagnostic sensitivity of 75% and specificity of 80% and showed a similar diagnostic performance compared to LLC in receiver-operating-curve analyses. Combining madSD, maxT2 and late gadolinium enhancement (LGE) in a model resulted in a superior diagnostic performance compared to LLC (sensitivity 93%, specificity 83%). The results show that the novel T2-mapping-derived parameters exhibit an additional diagnostic value over LGE with the inherent potential to overcome the current limitations of T2-mapping. • A novel quantitative approach to myocardial oedema imaging in myocarditis was re-evaluated. • The T2-mapping-derived parameters maxT2 and madSD were compared to traditional Lake-Louise criteria. • Using maxT2 and madSD with dedicated cut-offs performs similarly to Lake-Louise criteria. • Adding maxT2 and madSD to LGE results in further increased diagnostic performance. • This novel approach has the potential to overcome the limitations of T2-mapping.

  14. Neural net generated seismic facies map and attribute facies map

    International Nuclear Information System (INIS)

    Addy, S.K.; Neri, P.

    1998-01-01

    The usefulness of 'seismic facies maps' in the analysis of an Upper Wilcox channel system in a 3-D survey shot by CGG in 1995 in Lavaca county in south Texas was discussed. A neural net-generated seismic facies map is a quick hydrocarbon exploration tool that can be applied regionally as well as on a prospect scale. The new technology is used to classify a constant interval parallel to a horizon in a 3-D seismic volume based on the shape of the wiggle traces using a neural network technology. The tool makes it possible to interpret sedimentary features of a petroleum deposit. The same technology can be used in regional mapping by making 'attribute facies maps' in which various forms of amplitude attributes, phase attributes or frequency attributes can be used

  15. Cerebral gray matter volume losses in essential tremor: A case-control study using high resolution tissue probability maps.

    Science.gov (United States)

    Cameron, Eric; Dyke, Jonathan P; Hernandez, Nora; Louis, Elan D; Dydak, Ulrike

    2018-03-10

    Essential tremor (ET) is increasingly recognized as a multi-dimensional disorder with both motor and non-motor features. For this reason, imaging studies are more broadly examining regions outside the cerebellar motor loop. Reliable detection of cerebral gray matter (GM) atrophy requires optimized processing, adapted to high-resolution magnetic resonance imaging (MRI). We investigated cerebral GM volume loss in ET cases using automated segmentation of MRI T1-weighted images. MRI was acquired on 47 ET cases and 36 controls. Automated segmentation and voxel-wise comparisons of volume were performed using Statistical Parametric Mapping (SPM) software. To improve upon standard protocols, the high-resolution International Consortium for Brain Mapping (ICBM) 2009a atlas and tissue probability maps were used to process each subject image. Group comparisons were performed: all ET vs. Controls, ET with head tremor (ETH) vs. Controls, and severe ET vs. An analysis of variance (ANOVA) was performed between ET with and without head tremor and controls. Age, sex, and Montreal Cognitive Assessment (MoCA) score were regressed out from each comparison. We were able to consistently identify regions of cerebral GM volume loss in ET and in ET subgroups in the posterior insula, superior temporal gyri, cingulate cortex, inferior frontal gyri and other occipital and parietal regions. There were no significant increases in GM volume in ET in any comparisons with controls. This study, which uses improved methodologies, provides evidence that GM volume loss in ET is present beyond the cerebellum, and in fact, is widespread throughout the cerebrum as well. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Mapping by monoclonal antibody detection of glycosaminoglycans in connective tissues

    DEFF Research Database (Denmark)

    Couchman, J R; Caterson, B; Christner, J E

    1984-01-01

    Chondroitin sulphate proteoglycans are widespread connective tissue components and chemical analysis of cartilage and other proteoglycans has demonstrated molecular speciation involving the degree and position of sulphation of the carbohydrate chains. This may, in turn, affect the properties...... of the glycosaminoglycan (GAG), particularly with respect to self-association and interactions with other extracellular matrix components. Interactions with specific molecules from different connective tissue types, such as the collagens and their associated glycoproteins, could be favoured by particular charge...... and dermatan sulphate. These provide novel opportunities to study the in vivo distribution of chondroitin sulphate proteoglycans. We demonstrate that chondroitin sulphates exhibit remarkable connective tissue specificity and furthermore provide evidence that some proteoglycans may predominantly carry only one...

  17. Liquid chromatography tandem mass spectrometry method using solid-phase extraction and bead-beating-assisted matrix solid-phase dispersion to quantify the fungicide tebuconazole in controlled frog exposure study: analysis of water and animal tissue

    DEFF Research Database (Denmark)

    Hansen, Martin; Poulsen, Rikke; Luong, Xuan

    2014-01-01

    and on tissue from exposed and non-exposed adult X. laevis. Using solid-phase extraction (SPE), the analytical method allows for quantification of tebuconazole at concentrations as low as 3.89 pg mL(-1) in 10 mL water samples. Using bead-beating-assisted matrix solid-phase dispersion (MSPD), it was possible...

  18. Nanomechanical mapping of bone tissue regenerated by magnetic scaffolds.

    Science.gov (United States)

    Bianchi, Michele; Boi, Marco; Sartori, Maria; Giavaresi, Gianluca; Lopomo, Nicola; Fini, Milena; Dediu, Alek; Tampieri, Anna; Marcacci, Maurilio; Russo, Alessandro

    2015-01-01

    Nanoindentation can provide new insights on the maturity stage of regenerating bone. The aim of the present study was the evaluation of the nanomechanical properties of newly-formed bone tissue at 4 weeks from the implantation of permanent magnets and magnetic scaffolds in the trabecular bone of rabbit femoral condyles. Three different groups have been investigated: MAG-A (NdFeB magnet + apatite/collagen scaffold with magnetic nanoparticles directly nucleated on the collagen fibers during scaffold synthesis); MAG-B (NdFeB magnet + apatite/collagen scaffold later infiltrated with magnetic nanoparticles) and MAG (NdFeB magnet). The mechanical properties of different-maturity bone tissues, i.e. newly-formed immature, newly-formed mature and native trabecular bone have been evaluated for the three groups. Contingent correlations between elastic modulus and hardness of immature, mature and native bone have been examined and discussed, as well as the efficacy of the adopted regeneration method in terms of "mechanical gap" between newly-formed and native bone tissue. The results showed that MAG-B group provided regenerated bone tissue with mechanical properties closer to that of native bone compared to MAG-A or MAG groups after 4 weeks from implantation. Further, whereas the mechanical properties of newly-formed immature and mature bone were found to be fairly good correlated, no correlation was detected between immature or mature bone and native bone. The reported results evidence the efficacy of nanoindentation tests for the investigation of the maturity of newly-formed bone not accessible through conventional analyses.

  19. Phase-changes in cell cycle of wound tissue irradiated with 5.21 Gy soft X-rays

    International Nuclear Information System (INIS)

    Liu Jianzhong; Zhou Yuanguo; Cheng Tianmin; Zhou Ping; Liu Xia; Li Ping

    2002-01-01

    Objective: To study the phase-changes in cell cycle of wound tissue which was locally irradiated with 5.21 Gy soft X-rays. Methods: Flow cytometry and PI staining were used to analyze cell cycle. Cell proliferation was determined with BrdU labeling. Results: During 3-9 days after irradiation, the percentage of the G 0 /G 1 phase cells in wound of the control side decreased while the percentage of S phase cells increased and reached the highest value on day 9. The percentage of G 2 /M phase cells also increased, and reached its peak on day 15. The percentage of G 0 /G 1 phase cell increased in wound of the irradiation side and was higher than that of the control wound, meanwhile the percentages of S and G 2 /M cells were significantly lower than those of the control wound. In the period of 12-22 days after wounding, the percentage of S phase cells increased and reached its peak value on the 22 th day. When most of cells were in S phase and arrested dramatically. Through the whole healing process, the percentage of G 2 /M in wound of the irradiation side was lower than that of the non-irradiated wound. The BrdU-positive cells were fibroblasts, endothelial cells and smooth muscle cells. Conclusion: These results suggest that G 1 block, S phase arrest, and switch of G 2 /M with suppression of mitotic activity of these cells are induced by local 5.21 Gy soft X-ray irradiation. Therefore, wound healing delay is induced partly by cell cycle arrest

  20. Spatiotemporal dynamics of a digital phase-locked loop based coupled map lattice system

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Tanmoy, E-mail: tbanerjee@phys.buruniv.ac.in; Paul, Bishwajit; Sarkar, B. C. [Department of Physics, University of Burdwan, Burdwan, West Bengal 713 104 (India)

    2014-03-15

    We explore the spatiotemporal dynamics of a coupled map lattice (CML) system, which is realized with a one dimensional array of locally coupled digital phase-locked loops (DPLLs). DPLL is a nonlinear feedback-controlled system widely used as an important building block of electronic communication systems. We derive the phase-error equation of the spatially extended system of coupled DPLLs, which resembles a form of the equation of a CML system. We carry out stability analysis for the synchronized homogeneous solutions using the circulant matrix formalism. It is shown through extensive numerical simulations that with the variation of nonlinearity parameter and coupling strength the system shows transitions among several generic features of spatiotemporal dynamics, viz., synchronized fixed point solution, frozen random pattern, pattern selection, spatiotemporal intermittency, and fully developed spatiotemporal chaos. We quantify the spatiotemporal dynamics using quantitative measures like average quadratic deviation and spatial correlation function. We emphasize that instead of using an idealized model of CML, which is usually employed to observe the spatiotemporal behaviors, we consider a real world physical system and establish the existence of spatiotemporal chaos and other patterns in this system. We also discuss the importance of the present study in engineering application like removal of clock-skew in parallel processors.

  1. Photogrammetry, Digital mapping and Land Informations Systems

    DEFF Research Database (Denmark)

    Frederiksen, Poul

    1998-01-01

    Monitoring activities on photogrammetry, digital mapping and land information systems in State Land Service in Latvia in relation to the EU Phare Project Phase II, Technical Assistance to land Privatisation and registration in Latvia.......Monitoring activities on photogrammetry, digital mapping and land information systems in State Land Service in Latvia in relation to the EU Phare Project Phase II, Technical Assistance to land Privatisation and registration in Latvia....

  2. International Mapping of Antenna-Measurement Facilities

    DEFF Research Database (Denmark)

    Boccia, Luigi; Breinbjerg, Olav; Di Massa, Giuseppe

    2006-01-01

    This paper presents a comprehensive international mapping of antenna-measurement facilities. This initiative, conducted within the framework of the Antenna Centre of Excellence (ACE) of the European Union, is oriented toward all institutions having research, development, or operational activities...... measurements, in particular from the wireless communication industry, to identify and contact antenna-measurement facilities. The first phase of the mapping showed a significant and encouraging reaction to this initiative, with more than 50 European facilities currently registered. The next phase aims...

  3. Mechanical Characterization of Tissue-Engineered Cartilage Using Microscopic Magnetic Resonance Elastography

    Science.gov (United States)

    Yin, Ziying; Schmid, Thomas M.; Yasar, Temel K.; Liu, Yifei; Royston, Thomas J.

    2014-01-01

    Knowledge of mechanical properties of tissue-engineered cartilage is essential for the optimization of cartilage tissue engineering strategies. Microscopic magnetic resonance elastography (μMRE) is a recently developed MR-based technique that can nondestructively visualize shear wave motion. From the observed wave pattern in MR phase images the tissue mechanical properties (e.g., shear modulus or stiffness) can be extracted. For quantification of the dynamic shear properties of small and stiff tissue-engineered cartilage, μMRE needs to be performed at frequencies in the kilohertz range. However, at frequencies greater than 1 kHz shear waves are rapidly attenuated in soft tissues. In this study μMRE, with geometric focusing, was used to overcome the rapid wave attenuation at high frequencies, enabling the measurement of the shear modulus of tissue-engineered cartilage. This methodology was first tested at a frequency of 5 kHz using a model system composed of alginate beads embedded in agarose, and then applied to evaluate extracellular matrix development in a chondrocyte pellet over a 3-week culture period. The shear stiffness in the pellet was found to increase over time (from 6.4 to 16.4 kPa), and the increase was correlated with both the proteoglycan content and the collagen content of the chondrocyte pellets (R2=0.776 and 0.724, respectively). Our study demonstrates that μMRE when performed with geometric focusing can be used to calculate and map the shear properties within tissue-engineered cartilage during its development. PMID:24266395

  4. The correlation of the results of capacitance mapping and of sheet resistance mapping in semi-insulating 6H-SiC

    International Nuclear Information System (INIS)

    Lin Shenghuang; Chen Zhiming; Liang Peng; Jiang Dong; Xie Huajie; Yang Ying

    2010-01-01

    A combination of complex surface capacitance mapping and sheet resistance mapping is applied to establish the origin of resistance variations on semi-insulating (SI) 6H-SiC substrates. The direct correlation between the capacitance quadrature and the sheet resistance is found in vanadium-doped SI samples. Regions with low capacitance quadrature show high sheet resistance. This indicates, associated with the nonhomogeneity of sheet resistance on the substrate, that the quality of crystallization is not good enough, which also leads to resistivity nonhomogeneity when comparing with different types of deep defects. According to the capacitance mapping, the region with bad crystallization quality has a high radio absorption coefficient. Another correlation is established between the capacitance in-phase and sheet resistance for the vanadium-doped sample. In this sample, the capacitance in-phase map shows not only the surface topography, but also the same distribution trend as the sheet resistance, namely, regions of high capacitance in-phase reveal high sheet resistance.

  5. Renormalization in area-preserving maps

    CERN Document Server

    MacKay, R S

    1993-01-01

    This book is adapted and revised from the author's seminal PhD thesis, in which two forms of asymptotically universal structure were presented and explained for area-preserving maps. Area-preserving maps are the discrete-time analogue of two degree-of-freedom Hamiltonian systems. How they work and much of their dynamics are described in this book. The asymptotically universal structure is found on small scales in phase-space and long time-scales. The key to understanding it is renormalisation, that is, looking at a system on successively smaller phase-space and longer time scales. Having prese

  6. Mapping health outcomes from ecosystem services

    NARCIS (Netherlands)

    Keune, Hans; Oosterbroek, Bram; Derkzen, Marthe; Subramanian, Suneetha; Payyappalimana, Unnikrishnan; Martens, Pim; Huynen, Maud; Burkhard, Benjamin; Maes, Joachim

    The practice of mapping ecosystem services (ES) in relation to health outcomes is only in its early developing phases. Examples are provided of health outcomes, health proxies and related biophysical indicators. This chapter also covers main health mapping challenges, design options and

  7. Noncontact measurement of elasticity for the detection of soft-tissue tumors using phase-sensitive optical coherence tomography combined with a focused air-puff system.

    Science.gov (United States)

    Wang, Shang; Li, Jiasong; Manapuram, Ravi Kiran; Menodiado, Floredes M; Ingram, Davis R; Twa, Michael D; Lazar, Alexander J; Lev, Dina C; Pollock, Raphael E; Larin, Kirill V

    2012-12-15

    We report on an optical noncontact method for the detection of soft-tissue tumors based on the measurement of their elasticity. A focused air-puff system is used to excite surface waves (SWs) on soft tissues with transient static pressure. A high-speed phase-sensitive optical coherence tomography system is used to measure the SWs as they propagate from the point of excitation. To evaluate the stiffness of soft tissues, the Young's modulus is quantified based on the group velocity of SWs. Pilot experiments were performed on ex vivo human myxoma and normal fat. Results demonstrate the feasibility of the proposed method to measure elasticity and differentiate soft-tissue tumors from normal tissues.

  8. Fostering clinical reasoning in physiotherapy: comparing the effects of concept map study and concept map completion after example study in novice and advanced learners.

    Science.gov (United States)

    Montpetit-Tourangeau, Katherine; Dyer, Joseph-Omer; Hudon, Anne; Windsor, Monica; Charlin, Bernard; Mamede, Sílvia; van Gog, Tamara

    2017-12-01

    Health profession learners can foster clinical reasoning by studying worked examples presenting fully worked out solutions to a clinical problem. It is possible to improve the learning effect of these worked examples by combining them with other learning activities based on concept maps. This study investigated which combinaison of activities, worked examples study with concept map completion or worked examples study with concept map study, fosters more meaningful learning of intervention knowledge in physiotherapy students. Moreover, this study compared the learning effects of these learning activity combinations between novice and advanced learners. Sixty-one second-year physiotherapy students participated in the study which included a pre-test phase, a 130-min guided-learning phase and a four-week self-study phase. During the guided and self-study learning sessions, participants had to study three written worked examples presenting the clinical reasoning for selecting electrotherapeutic currents to treat patients with motor deficits. After each example, participants engaged in either concept map completion or concept map study depending on which learning condition they were randomly allocated to. Students participated in an immediate post-test at the end of the guided-learning phase and a delayed post-test at the end of the self-study phase. Post-tests assessed the understanding of principles governing the domain of knowledge to be learned (conceptual knowledge) and the ability to solve new problems that have similar (i.e., near transfer) or different (i.e., far transfer) solution rationales as problems previously studied in the examples. Learners engaged in concept map completion outperformed those engaged in concept map study on near transfer (p = .010) and far transfer (p concept map completion led to greater transfer performance than worked examples study combined with concept map study for both novice and advanced learners. Concept map completion

  9. Phase-coded multi-pulse technique for ultrasonic high-order harmonic imaging of biological tissues in vitro

    International Nuclear Information System (INIS)

    Ma Qingyu; Zhang Dong; Gong Xiufen; Ma Yong

    2007-01-01

    Second or higher order harmonic imaging shows significant improvement in image clarity but is degraded by low signal-noise ratio (SNR) compared with fundamental imaging. This paper presents a phase-coded multi-pulse technique to provide the enhancement of SNR for the desired high-order harmonic ultrasonic imaging. In this technique, with N phase-coded pulses excitation, the received Nth harmonic signal is enhanced by 20 log 10 N dB compared with that in the single-pulse mode, whereas the fundamental and other order harmonic components are efficiently suppressed to reduce image confusion. The principle of this technique is theoretically discussed based on the theory of the finite amplitude sound waves, and examined by measurements of the axial and lateral beam profiles as well as the phase shift of the harmonics. In the experimental imaging for two biological tissue specimens, a plane piston source at 2 MHz is used to transmit a sequence of multiple pulses with equidistant phase shift. The second to fifth harmonic images are obtained using this technique with N = 2 to 5, and compared with the images obtained at the fundamental frequency. Results demonstrate that this technique of relying on higher order harmonics seems to provide a better resolution and contrast of ultrasonic images

  10. The role of acoustic nonlinearity in tissue heating behind a rib cage using a high-intensity focused ultrasound phased array

    Science.gov (United States)

    Yuldashev, Petr V.; Shmeleva, Svetlana M.; Ilyin, Sergey A.; Sapozhnikov, Oleg A.; Gavrilov, Leonid R.; Khokhlova, Vera A.

    2013-04-01

    The goal of this study was to investigate theoretically the effects of nonlinear propagation in a high-intensity focused ultrasound (HIFU) field produced by a therapeutic phased array and the resultant heating of tissue behind a rib cage. Three configurations of focusing were simulated: in water, in water with ribs in the beam path and in water with ribs backed by a layer of soft tissue. The Westervelt equation was used to model the nonlinear HIFU field, and a 1 MHz phased array consisting of 254 circular elements was used as a boundary condition to the model. The temperature rise in tissue was modelled using the bioheat equation, and thermally necrosed volumes were calculated using the thermal dose formulation. The shapes of lesions predicted by the modelling were compared with those previously obtained in in vitro experiments at low-power sonications. Intensity levels at the face of the array elements that corresponded to the formation of high-amplitude shock fronts in the focal region were determined as 10 W cm-2 in the free field in water and 40 W cm-2 in the presence of ribs. It was shown that exposures with shocks provided a substantial increase in tissue heating, and its better spatial localization in the main focal region only. The relative effects of overheating ribs and splitting of the focus due to the periodic structure of the ribs were therefore reduced. These results suggest that utilizing nonlinear propagation and shock formation effects can be beneficial for inducing confined HIFU lesions when irradiating through obstructions such as ribs. Design of compact therapeutic arrays to provide maximum power outputs with lower intensity levels at the elements is necessary to achieve shock wave regimes for clinically relevant sonication depths in tissue.

  11. Colorectal carcinoma: Ex vivo evaluation using 3-T high-spatial-resolution quantitative T2 mapping and its correlation with histopathologic findings.

    Science.gov (United States)

    Yamada, Ichiro; Yoshino, Norio; Hikishima, Keigo; Miyasaka, Naoyuki; Yamauchi, Shinichi; Uetake, Hiroyuki; Yasuno, Masamichi; Saida, Yukihisa; Tateishi, Ukihide; Kobayashi, Daisuke; Eishi, Yoshinobu

    2017-05-01

    In this study, we aimed to evaluate the feasibility of determining the mural invasion depths of colorectal carcinomas using high-spatial-resolution (HSR) quantitative T2 mapping on a 3-T magnetic resonance (MR) scanner. Twenty colorectal specimens containing adenocarcinomas were imaged on a 3-T MR system equipped with a 4-channel phased-array surface coil. HSR quantitative T2 maps were acquired using a spin-echo sequence with a repetition time/echo time of 7650/22.6-361.6ms (16 echoes), 87×43.5-mm field of view, 2-mm section thickness, 448×224 matrix, and average of 1. HSR fast-spin-echo T2-weighted images were also acquired. Differences between the T2 values (ms) of the tumor tissue, colorectal wall layers, and fibrosis were measured, and the MR images and histopathologic findings were compared. In all specimens (20/20, 100%), the HSR quantitative T2 maps clearly depicted an 8-layer normal colorectal wall in which the T2 values of each layer differed from those of the adjacent layer(s) (PT2 maps and histopathologic data yielded the same findings regarding the tumor invasion depth. Our results indicate that 3-T HSR quantitative T2 mapping is useful for distinguishing colorectal wall layers and differentiating tumor and fibrotic tissues. Accordingly, this technique could be used to determine mural invasion by colorectal carcinomas with a high level of accuracy. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Improving experimental phases for strong reflections prior to density modification

    International Nuclear Information System (INIS)

    Uervirojnangkoorn, Monarin; Hilgenfeld, Rolf; Terwilliger, Thomas C.; Read, Randy J.

    2013-01-01

    A genetic algorithm has been developed to optimize the phases of the strongest reflections in SIR/SAD data. This is shown to facilitate density modification and model building in several test cases. Experimental phasing of diffraction data from macromolecular crystals involves deriving phase probability distributions. These distributions are often bimodal, making their weighted average, the centroid phase, improbable, so that electron-density maps computed using centroid phases are often non-interpretable. Density modification brings in information about the characteristics of electron density in protein crystals. In successful cases, this allows a choice between the modes in the phase probability distributions, and the maps can cross the borderline between non-interpretable and interpretable. Based on the suggestions by Vekhter [Vekhter (2005 ▶), Acta Cryst. D61, 899–902], the impact of identifying optimized phases for a small number of strong reflections prior to the density-modification process was investigated while using the centroid phase as a starting point for the remaining reflections. A genetic algorithm was developed that optimizes the quality of such phases using the skewness of the density map as a target function. Phases optimized in this way are then used in density modification. In most of the tests, the resulting maps were of higher quality than maps generated from the original centroid phases. In one of the test cases, the new method sufficiently improved a marginal set of experimental SAD phases to enable successful map interpretation. A computer program, SISA, has been developed to apply this method for phase improvement in macromolecular crystallography

  13. Neo-adjuvant chemotherapy alone or with regional hyperthermia for localised high-risk soft-tissue sarcoma: a randomised phase 3 multicentre study

    DEFF Research Database (Denmark)

    Issels, Rolf D; Lindner, Lars H; Verweij, Jaap

    2010-01-01

    The optimum treatment for high-risk soft-tissue sarcoma (STS) in adults is unclear. Regional hyperthermia concentrates the action of chemotherapy within the heated tumour region. Phase 2 studies have shown that chemotherapy with regional hyperthermia improves local control compared with chemother...

  14. Hardmetals - microstructural design, testing and property maps

    Energy Technology Data Exchange (ETDEWEB)

    Roebuck, B; Gee, M G; Morrell, R [NPL Materials Centre, National Physical Laboratory, Teddington, Middlesex (United Kingdom)

    2001-07-01

    The production of WC/Co hardmetals and their analogues is considered a mature technology, however lately there has been new research results where the concept of microstructural design was used to produce alternatives to the conventional two-phase structure. This Industry is currently well served by a range of baseline established standards, which, if properly followed with good attention to correct quality procedures, will ensure consistent products. However, there are certain key properties such as corrosion, fatigue, impact wear or high temperature strength and toughness that are often measured but not always by standard tests methods. Microstructural design potential is reviewed, particularly the possibilities of performance improvement via changes in size, shape and distribution of the phases as well as recent developments in testing, specifically S-N fatigue and abrasive wear. Finally, the concept of property mapping is introduced as a tool for providing a framework for optimizing properties. Its utility in correlating performance properties and their relationships with microstructural parameters is evaluated. Two property maps are discussed: one where the property is plotted against a microstructural feature (microstructure property maps) such as WC grain size or Co binder phase content against coercivity or hardness and one where different properties, such as hardness and toughness are mapped against each other (comparative property maps). (nevyjel)

  15. Hardmetals - microstructural design, testing and property maps

    International Nuclear Information System (INIS)

    Roebuck, B.; Gee, M.G.; Morrell, R.

    2001-01-01

    The production of WC/Co hardmetals and their analogues is considered a mature technology, however lately there has been new research results where the concept of microstructural design was used to produce alternatives to the conventional two-phase structure. This Industry is currently well served by a range of baseline established standards, which, if properly followed with good attention to correct quality procedures, will ensure consistent products. However, there are certain key properties such as corrosion, fatigue, impact wear or high temperature strength and toughness that are often measured but not always by standard tests methods. Microstructural design potential is reviewed, particularly the possibilities of performance improvement via changes in size, shape and distribution of the phases as well as recent developments in testing, specifically S-N fatigue and abrasive wear. Finally, the concept of property mapping is introduced as a tool for providing a framework for optimizing properties. Its utility in correlating performance properties and their relationships with microstructural parameters is evaluated. Two property maps are discussed: one where the property is plotted against a microstructural feature (microstructure property maps) such as WC grain size or Co binder phase content against coercivity or hardness and one where different properties, such as hardness and toughness are mapped against each other (comparative property maps). (nevyjel)

  16. Unwrapped phase inversion with an exponential damping

    KAUST Repository

    Choi, Yun Seok

    2015-07-28

    Full-waveform inversion (FWI) suffers from the phase wrapping (cycle skipping) problem when the frequency of data is not low enough. Unless we obtain a good initial velocity model, the phase wrapping problem in FWI causes a result corresponding to a local minimum, usually far away from the true solution, especially at depth. Thus, we have developed an inversion algorithm based on a space-domain unwrapped phase, and we also used exponential damping to mitigate the nonlinearity associated with the reflections. We construct the 2D phase residual map, which usually contains the wrapping discontinuities, especially if the model is complex and the frequency is high. We then unwrap the phase map and remove these cycle-based jumps. However, if the phase map has several residues, the unwrapping process becomes very complicated. We apply a strong exponential damping to the wavefield to eliminate much of the residues in the phase map, thus making the unwrapping process simple. We finally invert the unwrapped phases using the back-propagation algorithm to calculate the gradient. We progressively reduce the damping factor to obtain a high-resolution image. Numerical examples determined that the unwrapped phase inversion with a strong exponential damping generated convergent long-wavelength updates without low-frequency information. This model can be used as a good starting model for a subsequent inversion with a reduced damping, eventually leading to conventional waveform inversion.

  17. Map Archive Mining: Visual-Analytical Approaches to Explore Large Historical Map Collections

    Directory of Open Access Journals (Sweden)

    Johannes H. Uhl

    2018-04-01

    Full Text Available Historical maps are unique sources of retrospective geographical information. Recently, several map archives containing map series covering large spatial and temporal extents have been systematically scanned and made available to the public. The geographical information contained in such data archives makes it possible to extend geospatial analysis retrospectively beyond the era of digital cartography. However, given the large data volumes of such archives (e.g., more than 200,000 map sheets in the United States Geological Survey topographic map archive and the low graphical quality of older, manually-produced map sheets, the process to extract geographical information from these map archives needs to be automated to the highest degree possible. To understand the potential challenges (e.g., salient map characteristics and data quality variations in automating large-scale information extraction tasks for map archives, it is useful to efficiently assess spatio-temporal coverage, approximate map content, and spatial accuracy of georeferenced map sheets at different map scales. Such preliminary analytical steps are often neglected or ignored in the map processing literature but represent critical phases that lay the foundation for any subsequent computational processes including recognition. Exemplified for the United States Geological Survey topographic map and the Sanborn fire insurance map archives, we demonstrate how such preliminary analyses can be systematically conducted using traditional analytical and cartographic techniques, as well as visual-analytical data mining tools originating from machine learning and data science.

  18. Wavelet analysis of polarization azimuths maps for laser images of myocardial tissue for the purpose of diagnosing acute coronary insufficiency

    Science.gov (United States)

    Wanchuliak, O. Ya.; Peresunko, A. P.; Bakko, Bouzan Adel; Kushnerick, L. Ya.

    2011-09-01

    This paper presents the foundations of a large scale - localized wavelet - polarization analysis - inhomogeneous laser images of histological sections of myocardial tissue. Opportunities were identified defining relations between the structures of wavelet coefficients and causes of death. The optical model of polycrystalline networks of myocardium protein fibrils is presented. The technique of determining the coordinate distribution of polarization azimuth of the points of laser images of myocardium histological sections is suggested. The results of investigating the interrelation between the values of statistical (statistical moments of the 1st-4th order) parameters are presented which characterize distributions of wavelet - coefficients polarization maps of myocardium layers and death reasons.

  19. Geotechnical Mapping of An-Najaf City, Iraq

    Directory of Open Access Journals (Sweden)

    Nadher Hassan Al-Baghdadi

    2016-12-01

    Full Text Available The present paper submits a set geotechnical maps for the area of An-Najaf city, by using contour lines to represent the different geotechnical properties of the soil. The present research work is very important step toward preparing a geotechnical database for this region, to complete the geotechnical database over all the country, (Iraq. Using such a database is very important in geotechincal investigation, reconnaissance phase, of construction projects. Within this phase of site investigation, numbers, depths and locations of the boreholes needed, will be determined. A well known commercial software (SURFER 11, was used to produce the all the contour maps of geotechnical properties presented herein. A forty nine (49 contour maps were produced to cover the variations, within the geotechnical properties of the soil, to produce realistic description to these soil properties. Both Google maps and Universal Transverse Mercator coordinate system (UTM have been used in the contour maps for easy use.

  20. Bifurcation and Fractal of the Coupled Logistic Map

    Science.gov (United States)

    Wang, Xingyuan; Luo, Chao

    The nature of the fixed points of the coupled Logistic map is researched, and the boundary equation of the first bifurcation of the coupled Logistic map in the parameter space is given out. Using the quantitative criterion and rule of system chaos, i.e., phase graph, bifurcation graph, power spectra, the computation of the fractal dimension, and the Lyapunov exponent, the paper reveals the general characteristics of the coupled Logistic map transforming from regularity to chaos, the following conclusions are shown: (1) chaotic patterns of the coupled Logistic map may emerge out of double-periodic bifurcation and Hopf bifurcation, respectively; (2) during the process of double-period bifurcation, the system exhibits self-similarity and scale transform invariability in both the parameter space and the phase space. From the research of the attraction basin and Mandelbrot-Julia set of the coupled Logistic map, the following conclusions are indicated: (1) the boundary between periodic and quasiperiodic regions is fractal, and that indicates the impossibility to predict the moving result of the points in the phase plane; (2) the structures of the Mandelbrot-Julia sets are determined by the control parameters, and their boundaries have the fractal characteristic.

  1. Speedup of minimum discontinuity phase unwrapping algorithm with a reference phase distribution

    Science.gov (United States)

    Liu, Yihang; Han, Yu; Li, Fengjiao; Zhang, Qican

    2018-06-01

    In three-dimensional (3D) shape measurement based on phase analysis, the phase analysis process usually produces a wrapped phase map ranging from - π to π with some 2 π discontinuities, and thus a phase unwrapping algorithm is necessary to recover the continuous and nature phase map from which 3D height distribution can be restored. Usually, the minimum discontinuity phase unwrapping algorithm can be used to solve many different kinds of phase unwrapping problems, but its main drawback is that it requires a large amount of computations and has low efficiency in searching for the improving loop within the phase's discontinuity area. To overcome this drawback, an improvement to speedup of the minimum discontinuity phase unwrapping algorithm by using the phase distribution on reference plane is proposed. In this improved algorithm, before the minimum discontinuity phase unwrapping algorithm is carried out to unwrap phase, an integer number K was calculated from the ratio of the wrapped phase to the nature phase on a reference plane. And then the jump counts of the unwrapped phase can be reduced by adding 2K π, so the efficiency of the minimum discontinuity phase unwrapping algorithm is significantly improved. Both simulated and experimental data results verify the feasibility of the proposed improved algorithm, and both of them clearly show that the algorithm works very well and has high efficiency.

  2. Effect of luminescence transport through adipose tissue on measurement of tissue temperature by using ZnCdS nanothermometers

    Science.gov (United States)

    Volkova, Elena K.; Yanina, Irina Yu.; Sagaydachnaya, Elena; Konyukhova, Julia G.; Kochubey, Vyacheslav I.; Tuchin, Valery V.

    2018-02-01

    The spectra of luminescence of ZnCdS nanoparticles (ZnCdS NPs) were measured and analyzed in a wide temperature range: from room to human body and further to a hyperthermic temperature resulting in tissue morphology change. The results show that the signal of luminescence of ZnCdS NPs placed within the tissue is reasonably good sensitive to temperature change and accompanied by phase transitions of lipid structures of adipose tissue. It is shown that the presence of a phase transition in adipose tissue upon its heating (polymorphic transformations of lipids) leads to a nonmonotonic temperature dependence of the intensity of luminescence for the nanoparticles introduced into adipose tissue. This is due to a change in the light scattering by the tissue. The light scattering of adipose tissue greatly distorts the results of temperature measurements. The application of these nanoparticles is possible for temperature measurements in very thin or weakly scattering samples.

  3. High resolution and high sensitivity methods for oligosaccharide mapping and characterization by normal phase high performance liquid chromatography following derivatization with highly fluorescent anthranilic acid.

    Science.gov (United States)

    Anumula, K R; Dhume, S T

    1998-07-01

    Facile labeling of oligosaccharides (acidic and neutral) in a nonselective manner was achieved with highly fluorescent anthranilic acid (AA, 2-aminobenzoic acid) (more than twice the intensity of 2-aminobenzamide, AB) for specific detection at very high sensitivity. Quantitative labeling in acetate-borate buffered methanol (approximately pH 5.0) at 80 degreesC for 60 min resulted in negligible or no desialylation of the oligosaccharides. A high resolution high performance liquid chromatographic method was developed for quantitative oligosaccharide mapping on a polymeric-NH2bonded (Astec) column operating under normal phase and anion exchange (NP-HPAEC) conditions. For isolation of oligosaccharides from the map by simple evaporation, the chromatographic conditions developed use volatile acetic acid-triethylamine buffer (approximately pH 4.0) systems. The mapping and characterization technology was developed using well characterized standard glycoproteins. The fluorescent oligosaccharide maps were similar to the maps obtained by the high pH anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD), except that the fluorescent maps contained more defined peaks. In the map, the oligosaccharides separated into groups based on charge, size, linkage, and overall structure in a manner similar to HPAEC-PAD with contribution of -COOH function from the label, anthranilic acid. However, selectivity of the column for sialic acid linkages was different. A second dimension normal phase HPLC (NP-HPLC) method was developed on an amide column (TSK Gel amide-80) for separation of the AA labeled neutral complex type and isomeric structures of high mannose type oligosaccharides. The oligosaccharides labeled with AA are compatible with biochemical and biophysical techniques, and use of matrix assisted laser desorption mass spectrometry for rapid determination of oligosaccharide mass map of glycoproteins is demonstrated. High resolution of NP-HPAEC and NP-HPLC methods

  4. Phase alteration compensation in reflection digital holography

    International Nuclear Information System (INIS)

    Rincon, O; Amezquita, R; Monroy, F

    2011-01-01

    The phase maps obtained from digital holographic microscopy techniques carry information about the axial lengths of the object under study. Additionally, these phase maps have information of tilt and curvatures with origin in the off-axis geometry and the magnification lenses system, respectively. Only a complete compensation of these extra phases allows a correct interpretation of the phase information. In this article a numerical strategy to compensate for these alterations is designed, using a phase mask located in different planes. This strategy is applied in the measurement of a phase steps plate using a digital holography setup.

  5. Designing a Multichannel Map Service Concept

    Directory of Open Access Journals (Sweden)

    Hanna-Marika Halkosaari

    2013-01-01

    Full Text Available This paper introduces a user-centered design process for developing a multichannel map service. The aim of the service is to provide hikers with interactive maps through several channels. In a multichannel map service, the same spatial information is available through various channels, such as printed maps, Web maps, mobile maps, and other interactive media. When properly networked, the channels share a uniform identity so that the user experiences the different channels as a part of a single map service. The traditional methods of user-centered design, such as design probes, personas, and scenarios, proved useful even in the emerging field of developing multichannel map services. The findings emphasize the need to involve users and multidisciplinary teams in the conceptual phases of designing complex services aimed at serving various kinds of users.

  6. Evaluating Uncertainty in GHG Emission Scenarios: Mapping IAM Outlooks With an Energy System Phase Space

    Science.gov (United States)

    Ritchie, W. J.; Dowlatabadi, H.

    2017-12-01

    Climate change modeling relies on projections of future greenhouse gas emissions and other phenomena leading to changes in planetary radiative forcing (RF). Pathways for long-run fossil energy use that map to total forcing outcomes are commonly depicted with integrated assessment models (IAMs). IAMs structure outlooks for 21st-century emissions with various theories for developments in demographics, economics, land-use, energy markets and energy service demands. These concepts are applied to understand global changes in two key factors relevant for scenarios of carbon emissions: total energy use (E) this century and the carbon intensity of that energy (F/E). A simple analytical and graphical approach can also illustrate the full range of outcomes for these variables to determine if IAMs provide sufficient coverage of the uncertainty space for future energy use. In this talk, we present a method for understanding uncertainties relevant to RF scenario components in a phase space. The phase space of a dynamic system represents significant factors as axes to capture the full range of physically possible states. A two-dimensional phase space of E and F/E presents the possible system states that can lead to various levels of total 21st-century carbon emissions. Once defined in this way, a phase space of these energy system coordinates allows for rapid characterization of large IAM scenario sets with machine learning techniques. This phase space method is applied to the levels of RF described by the Representative Concentration Pathways (RCPs). The resulting RCP phase space identifies characteristics of the baseline energy system outlooks provided by IAMs for IPCC Working Group III. We conduct a k-means cluster analysis to distinguish the major features of IAM scenarios for each RCP range. Cluster analysis finds the IAM scenarios in AR5 illustrate RCPs with consistent combinations of energy resources. This suggests IAM scenarios understate uncertainty ranges for future

  7. Evaluation and comparison of cartilage repair tissue of the patella and medial femoral condyle by using morphological MRI and biochemical zonal T2 mapping

    International Nuclear Information System (INIS)

    Welsch, Goetz H.; Mamisch, Tallal C.; Quirbach, Sebastian; Trattnig, Siegfried; Zak, Lukas; Marlovits, Stefan

    2009-01-01

    The objective of this study was to use advanced MR techniques to evaluate and compare cartilage repair tissue after matrix-associated autologous chondrocyte transplantation (MACT) in the patella and medial femoral condyle (MFC). Thirty-four patients treated with MACT underwent 3-T MRI of the knee. Patients were treated on either patella (n = 17) or MFC (n = 17) cartilage and were matched by age and postoperative interval. For morphological evaluation, the MR observation of cartilage repair tissue (MOCART) score was used, with a 3D-True-FISP sequence. For biochemical assessment, T2 mapping was prepared by using a multiecho spin-echo approach with particular attention to the cartilage zonal structure. Statistical evaluation was done by analyses of variance. The MOCART score showed no significant differences between the patella and MFC (p ≥ 0.05). With regard to biochemical T2 relaxation, higher T2 values were found throughout the MFC (p < 0.05). The zonal increase in T2 values from deep to superficial was significant for control cartilage (p < 0.001) and cartilage repair tissue (p < 0.05), with an earlier onset in the repair tissue of the patella. The assessment of cartilage repair tissue of the patella and MFC afforded comparable morphological results, whereas biochemical T2 values showed differences, possibly due to dissimilar biomechanical loading conditions. (orig.)

  8. Phase Composition Maps integrate mineral compositions with rock textures from the micro-meter to the thin section scale

    Science.gov (United States)

    Willis, Kyle V.; Srogi, LeeAnn; Lutz, Tim; Monson, Frederick C.; Pollock, Meagen

    2017-12-01

    Textures and compositions are critical information for interpreting rock formation. Existing methods to integrate both types of information favor high-resolution images of mineral compositions over small areas or low-resolution images of larger areas for phase identification. The method in this paper produces images of individual phases in which textural and compositional details are resolved over three orders of magnitude, from tens of micrometers to tens of millimeters. To construct these images, called Phase Composition Maps (PCMs), we make use of the resolution in backscattered electron (BSE) images and calibrate the gray scale values with mineral analyses by energy-dispersive X-ray spectrometry (EDS). The resulting images show the area of a standard thin section (roughly 40 mm × 20 mm) with spatial resolution as good as 3.5 μm/pixel, or more than 81 000 pixels/mm2, comparable to the resolution of X-ray element maps produced by wavelength-dispersive spectrometry (WDS). Procedures to create PCMs for mafic igneous rocks with multivariate linear regression models for minerals with solid solution (olivine, plagioclase feldspar, and pyroxenes) are presented and are applicable to other rock types. PCMs are processed using threshold functions based on the regression models to image specific composition ranges of minerals. PCMs are constructed using widely-available instrumentation: a scanning-electron microscope (SEM) with BSE and EDS X-ray detectors and standard image processing software such as ImageJ and Adobe Photoshop. Three brief applications illustrate the use of PCMs as petrologic tools: to reveal mineral composition patterns at multiple scales; to generate crystal size distributions for intracrystalline compositional zones and compare growth over time; and to image spatial distributions of minerals at different stages of magma crystallization by integrating textures and compositions with thermodynamic modeling.

  9. Using a concept map as a tool for strategic planning: The Healthy Brain Initiative.

    Science.gov (United States)

    Anderson, Lynda A; Day, Kristine L; Vandenberg, Anna E

    2011-09-01

    Concept mapping is a tool to assist in strategic planning that allows planners to work through a sequence of phases to produce a conceptual framework. Although several studies describe how concept mapping is applied to various public health problems, the flexibility of the methods used in each phase of the process is often overlooked. If practitioners were more aware of the flexibility, more public health endeavors could benefit from using concept mapping as a tool for strategic planning. The objective of this article is to describe how the 6 concept-mapping phases originally outlined by William Trochim guided our strategic planning process and how we adjusted the specific methods in the first 2 phases to meet the specialized needs and requirements to create The Healthy Brain Initiative: A National Public Health Road Map to Maintaining Cognitive Health. In the first stage (phases 1 and 2 of concept mapping), we formed a steering committee, convened 4 work groups over a period of 3 months, and generated an initial set of 42 action items grounded in science. In the second stage (phases 3 and 4), we engaged stakeholders in sorting and rating the action items and constructed a series of concept maps. In the third and final stage (phases 5 and 6), we examined and refined the action items and generated a final concept map consisting of 44 action items. We then selected the top 10 action items, and in 2007, we published The Healthy Brain Initiative: A National Public Health Road Map to Maintaining Cognitive Health, which represents the strategic plan for The Healthy Brain Initiative.

  10. Angiographic picture of soft tissue desmoid fibromas

    International Nuclear Information System (INIS)

    Nikitaev, N.S.; Kuznetsova, M.A.

    1987-01-01

    Arteriography was performed in 35 patients with soft tissue desmoid fibromas. Angiographic semiotics of this disease was described. The frequency of detectability of symptoms in the arterial, parenchymatous and venous phases was analyzed. A tumor in the arterial phase was shown to be of normevascular or moderately hypervascular type without noticeable winding of the nutrient arteries, such features of malignancy as lacunae and ''tumor'' vessels being absent. In the parenchymatous phase desmoid tumors were shown to accumulate moderately a contrast substance, a tumor contour at a vast length was ill defined and poorly marked from surrounding tissues. The venous phase was less noticeable and the time of its appearance was usually within normal. In general by most of its parameters the angiographic picture of agressive fibromatosis corresponded to that of benign tumors and could be used for differential diagnosis of desmoid fibromas and some types of tissue sarcomas

  11. Route planning with transportation network maps: an eye-tracking study.

    Science.gov (United States)

    Grison, Elise; Gyselinck, Valérie; Burkhardt, Jean-Marie; Wiener, Jan Malte

    2017-09-01

    Planning routes using transportation network maps is a common task that has received little attention in the literature. Here, we present a novel eye-tracking paradigm to investigate psychological processes and mechanisms involved in such a route planning. In the experiment, participants were first presented with an origin and destination pair before we presented them with fictitious public transportation maps. Their task was to find the connecting route that required the minimum number of transfers. Based on participants' gaze behaviour, each trial was split into two phases: (1) the search for origin and destination phase, i.e., the initial phase of the trial until participants gazed at both origin and destination at least once and (2) the route planning and selection phase. Comparisons of other eye-tracking measures between these phases and the time to complete them, which depended on the complexity of the planning task, suggest that these two phases are indeed distinct and supported by different cognitive processes. For example, participants spent more time attending the centre of the map during the initial search phase, before directing their attention to connecting stations, where transitions between lines were possible. Our results provide novel insights into the psychological processes involved in route planning from maps. The findings are discussed in relation to the current theories of route planning.

  12. Brain water mapping with MR imaging

    International Nuclear Information System (INIS)

    Laine, F.J.; Fatouros, P.P.; Kraft, K.A.

    1990-01-01

    This paper reports on a recently developed MR imaging technique to determine the spatial distribution of brain water to healthy volunteers. A noninvasive MR imaging technique to obtain absolute measurements of brain water has been developed and validated with phantom and animal studies. Patient confirmation was obtained from independent gravimetric measurements of brain tissue samples harvested by biopsy. This approach entails the production of accurate T1 maps from multiple inversion recovery images of a selected anatomic section and their subsequent conversion into an absolute water image by means of a previously determined calibration curve. Twenty healthy volunteers were studied and their water distribution was determined in a standard section. The following brain water values means and SD grams of water per gram of tissue) were obtained for selected brain regions; white matter, 68.9% ± 1.0; corpus callosum, 67.4% ± 1.1; thalamus, 75.3% ± 1.4; and caudate nucleus, 80.3% ± 1.4. MR imaging water mapping is a valid means of determining water content in a variety of brain tissues

  13. Culture-Independent Identification of Mycobacterium avium Subspecies paratuberculosis in Ovine Tissues: Comparison with Bacterial Culture and Histopathological Lesions

    Directory of Open Access Journals (Sweden)

    Kamal R. Acharya

    2017-12-01

    Full Text Available Johne’s disease is a chronic debilitating enteropathy of ruminants caused by Mycobacterium avium subspecies paratuberculosis (MAP. Current abattoir surveillance programs detect disease via examination of gross lesions and confirmation by histopathological and/or tissue culture, which is time-consuming and has relatively low sensitivity. This study aimed to investigate whether a high-throughput quantitative PCR (qPCR test is a viable alternative for tissue testing. Intestine and mesenteric lymph nodes were sourced from sheep experimentally infected with MAP and the DNA extracted using a protocol developed for tissues, comprised enzymatic digestion of the tissue homogenate, chemical and mechanical lysis, and magnetic bead-based DNA purification. The extracted DNA was tested by adapting a previously validated qPCR for fecal samples, and the results were compared with culture and histopathology results of the corresponding tissues. The MAP tissue qPCR confirmed infection in the majority of sheep with gross lesions on postmortem (37/38. Likewise, almost all tissue culture (61/64 or histopathology (52/58 positives were detected with good to moderate agreement (Cohen’s kappa statistic and no significant difference to the reference tests (McNemar’s Chi-square test. Higher MAP DNA quantities corresponded to animals with more severe histopathology (odds ratio: 1.82; 95% confidence interval: 1.60, 2.07. Culture-independent strain typing on tissue DNA was successfully performed. This MAP tissue qPCR method had a sensitivity equivalent to the reference tests and is thus a viable replacement for gross- and histopathological examination of tissue samples in abattoirs. In addition, the test could be validated for testing tissue samples intended for human consumption.

  14. Orientation and phase mapping in the transmission electron microscope using precession-assisted diffraction spot recognition: state-of-the-art results.

    Science.gov (United States)

    Viladot, D; Véron, M; Gemmi, M; Peiró, F; Portillo, J; Estradé, S; Mendoza, J; Llorca-Isern, N; Nicolopoulos, S

    2013-10-01

    A recently developed technique based on the transmission electron microscope, which makes use of electron beam precession together with spot diffraction pattern recognition now offers the possibility to acquire reliable orientation/phase maps with a spatial resolution down to 2 nm on a field emission gun transmission electron microscope. The technique may be described as precession-assisted crystal orientation mapping in the transmission electron microscope, precession-assisted crystal orientation mapping technique-transmission electron microscope, also known by its product name, ASTAR, and consists in scanning the precessed electron beam in nanoprobe mode over the specimen area, thus producing a collection of precession electron diffraction spot patterns, to be thereafter indexed automatically through template matching. We present a review on several application examples relative to the characterization of microstructure/microtexture of nanocrystalline metals, ceramics, nanoparticles, minerals and organics. The strengths and limitations of the technique are also discussed using several application examples. ©2013 The Authors. Journal of Microscopy published by John Wiley & Sons Ltd on behalf of Royal Microscopical Society.

  15. The use of Fourier reverse transforms in crystallographic phase refinement

    Energy Technology Data Exchange (ETDEWEB)

    Ringrose, Sharon [Iowa State Univ., Ames, IA (United States)

    1997-10-08

    Often a crystallographer obtains an electron density map which shows only part of the structure. In such cases, the phasing of the trial model is poor enough that the electron density map may show peaks in some of the atomic positions, but other atomic positions are not visible. There may also be extraneous peaks present which are not due to atomic positions. A method for determination of crystal structures that have resisted solution through normal crystallographic methods has been developed. PHASER is a series of FORTRAN programs which aids in the structure solution of poorly phased electron density maps by refining the crystallographic phases. It facilitates the refinement of such poorly phased electron density maps for difficult structures which might otherwise not be solvable. The trial model, which serves as the starting point for the phase refinement, may be acquired by several routes such as direct methods or Patterson methods. Modifications are made to the reverse transform process based on several assumptions. First, the starting electron density map is modified based on the fact that physically the electron density map must be non-negative at all points. In practice a small positive cutoff is used. A reverse Fourier transform is computed based on the modified electron density map. Secondly, the authors assume that a better electron density map will result by using the observed magnitudes of the structure factors combined with the phases calculated in the reverse transform. After convergence has been reached, more atomic positions and less extraneous peaks are observed in the refined electron density map. The starting model need not be very large to achieve success with PHASER; successful phase refinement has been achieved with a starting model that consists of only 5% of the total scattering power of the full molecule. The second part of the thesis discusses three crystal structure determinations.

  16. Phase-contrast microtomography using an X-ray interferometer having a 40-μm analyzer

    Science.gov (United States)

    Momose, A.; Koyama, I.; Hamaishi, Y.; Yoshikawa, H.; Takeda, T.; Wu, J.; Itai, Y.; Takai, , K.; Uesugi, K.; Suzuki, Y.

    2003-03-01

    Phase-contrast X-ray tomographic experiment using a triple Laue-case (LLL) interferometer having a 40-μm lamella which was fabricated to improve spatial resolution, was carried out using undulator X-rays at SPring-8, Japan. Three-dimensional images mapping the refractive index were measured for various animal tissues. Comparing the images with those obtained in previous experiments using conventional LLL interferometers having a 1-mm lamella, improvement in the spatial resolution was demonstrated in that histological structures, such as hepatic lobules in liver and tubules in kidney, were revealed.

  17. 3D map of theranostic nanoparticles distribution in mice brain and liver by means of X-ray Phase Contrast Tomography

    Science.gov (United States)

    Longo, E.; Bravin, A.; Brun, F.; Bukreeva, I.; Cedola, A.; Fratini, M.; Le Guevel, X.; Massimi, L.; Sancey, L.; Tillement, O.; Zeitoun, P.; de La Rochefoucauld, O.

    2018-01-01

    The word "theranostic" derives from the fusion of two terms: therapeutic and diagnostic. It is a promising research field that aims to develop innovative therapies with high target specificity by exploiting the therapeutic and diagnostic properties, in particular for metal-based nanoparticles (NPs) developed to erase cancer. In the framework of a combined research program on low dose X-ray imaging and theranostic nanoparticles (NPs), high resolution Phase-Contrast Tomography images of mice organs injected with gadolinium and gold-NPs were acquired at the European Synchrotron Radiation Facility (ESRF). Both compounds are good X-ray contrast agents due to their high attenuation coefficient with respect to biological tissues, especially immediately above K-edge energy. X-ray tomography is a powerful non-invasive technique to image the 3D vasculature network in order to detect abnormalities. Phase contrast methods provide more detailed anatomical information with higher discrimination among soft tissues. We present the images of mice liver and brain injected with gold and gadolinium NPs, respectively. We discuss different image processing methods used aiming at enhancing the accuracy on localizing nanoparticles.

  18. Simplified fringe order correction for absolute phase maps recovered with multiple-spatial-frequency fringe projections

    International Nuclear Information System (INIS)

    Ding, Yi; Peng, Kai; Lu, Lei; Zhong, Kai; Zhu, Ziqi

    2017-01-01

    Various kinds of fringe order errors may occur in the absolute phase maps recovered with multi-spatial-frequency fringe projections. In existing methods, multiple successive pixels corrupted by fringe order errors are detected and corrected pixel-by-pixel with repeating searches, which is inefficient for applications. To improve the efficiency of multiple successive fringe order corrections, in this paper we propose a method to simplify the error detection and correction by the stepwise increasing property of fringe order. In the proposed method, the numbers of pixels in each step are estimated to find the possible true fringe order values, repeating the search in detecting multiple successive errors can be avoided for efficient error correction. The effectiveness of our proposed method is validated by experimental results. (paper)

  19. Morphology of urethral tissues

    Science.gov (United States)

    Müller, Bert; Schulz, Georg; Herzen, Julia; Mushkolaj, Shpend; Bormann, Therese; Beckmann, Felix; Püschel, Klaus

    2010-09-01

    Micro computed tomography has been developed to a powerful technique for the characterization of hard and soft human and animal tissues. Soft tissues including the urethra, however, are difficult to be analyzed, since the microstructures of interest exhibit X-ray absorption values very similar to the surroundings. Selective staining using highly absorbing species is a widely used approach, but associated with significant tissue modification. Alternatively, one can suitably embed the soft tissue, which requires the exchange of water. Therefore, the more recently developed phase contrast modes providing much better contrast of low X-ray absorbing species are especially accommodating in soft tissue characterization. The present communication deals with the morphological characterization of sheep, pig and human urethras on the micrometer scale taking advantage of micro computed tomography in absorption and phase contrast modes. The performance of grating-based tomography is demonstrated for freshly explanted male and female urethras in saline solution. The micro-morphology of the urethra is important to understand how the muscles close the urethra to reach continence. As the number of incontinent patients is steadily increasing, the function under static and, more important, under stress conditions has to be uncovered for the realization of artificial urinary sphincters, which needs sophisticated, biologically inspired concepts to become nature analogue.

  20. Tissue engineering and regenerative medicine: manufacturing challenges.

    Science.gov (United States)

    Williams, D J; Sebastine, I M

    2005-12-01

    Tissue engineering and regenerative medicine are interdisciplinary fields that apply principles of engineering and life sciences to develop biological substitutes, typically composed of biological and synthetic components, that restore, maintain or improve tissue function. Many tissue engineering technologies are still at a laboratory or pre-commercial scale. The short review paper describes the most significant manufacturing and bio-process challenges inherent in the commercialisation and exploitation of the exciting results emerging from the biological and clinical laboratories exploring tissue engineering and regenerative medicine. A three-generation road map of the industry has been used to structure a view of these challenges and to define where the manufacturing community can contribute to the commercial success of the products from these emerging fields. The first-generation industry is characterised by its demonstrated clinical applications and products in the marketplace, the second is characterised by emerging clinical applications, and the third generation is characterised by aspirational clinical applications. The paper focuses on the cost reduction requirement of the first generation of the industry to allow more market penetration and consequent patient impact. It indicates the technological requirements, for instance the creation of three-dimensional tissue structures, and value chain issues in the second generation of the industry. The third-generation industry challenges lie in fundamental biological and clinical science. The paper sets out a road map of these generations to identify areas for research.

  1. Elastography: A New Ultrasound and MRI Procedure

    International Nuclear Information System (INIS)

    Pavan, Theo Z.; Vieira, Silvio L.; Carneiro, Antonio A. O.

    2008-01-01

    Elastography is an imaging technique whereby local tissue strains are estimated from small displacements of internal tissue structure. These displacements are generated from a weak, quasi-static or dynamic stress field. Displacement evaluation through ultrasound is based on time delay estimation between speckle patterns of echo maps acquired for different levels of tissue deformation. A classical model of deformation is applying a quasi-static compression on a sample during echoes acquisition. The elastogram map corresponds to the spatial derivation of the displacement map. By magnetic resonance, the displacement is evaluated from a map of phase acquired using a sequence gradient echo synchronized with a mechanical end sinusoidal excitation. The map of shear elastic modulus is obtained from the phase map

  2. Phase-contrast X-ray CT

    Energy Technology Data Exchange (ETDEWEB)

    Momose, Atsushi [Hitachi Ltd., Saitama (Japan). Advanced Research Laboratory; Takeda, Tohoru; Itai, Yuji

    1995-12-01

    Phase-contrast X-ray computed tomography (CT) enabling the observation of biological soft tissues without contrast enhancement has been developed. The X-ray phase shift caused by an object is measured and input to a standard CT reconstruction algorithm. A thousand times increase in the image sensitivity to soft tissues is achieved compared with the conventional CT using absorption contrast. This is because the X-ray phase shift cross section of light elements is about a thousand times larger than the absorption cross section. The phase shift is detected using an X-ray interferometer and computer analyses of interference patterns. Experiments were performed using a synchrotron X-ray source. Excellent image sensitivity is demonstrated in the observation of cancerous rabbit liver. The CT images distinguish cancer lesion from normal liver tissue and, moreover, visualize the pathological condition in the lesion. Although the X-ray energy employed and the present observation area size are not suitable for medical applications as they are, phase-contrast X-ray CT is promising for investigating the internal structure of soft tissue which is almost transparent for X-rays. The high sensitivity also provides the advantage of reducing X-ray doses. (author).

  3. Phase separation of in situ forming poly (lactide-co-glycolide acid) implants investigated using a hydrogel-based subcutaneous tissue surrogate and UV-vis imaging.

    Science.gov (United States)

    Sun, Yu; Jensen, Henrik; Petersen, Nickolaj J; Larsen, Susan W; Østergaard, Jesper

    2017-10-25

    Phase separation of in situ forming poly (lactide-co-glycolide acid) (PLGA) implants with agarose hydrogels as the provider of nonsolvent (water) mimicking subcutaneous tissue was investigated using a novel UV-vis imaging-based analytical platform. In situ forming implants of PLGA-1-methyl-2-pyrrolidinone and PLGA-triacetin representing fast and slow phase separating systems, respectively, were evaluated using this platform. Upon contact with the agarose hydrogel, the phase separation of the systems was followed by the study of changes in light transmission and absorbance as a function of time and position. For the PLGA-1-methyl-2-pyrrolidinone system, the rate of spatial phase separation was determined and found to decrease with increasing the PLGA concentration from 20% to 40% (w/w). Hydrogels with different agarose concentrations (1% and 10% (w/v)) were prepared for providing the nonsolvent, water, to the in situ forming PLGA implants simulating the injection site environment. The resulting implant morphology depended on the stiffness of hydrogel matrix, indicating that the matrix in which implants are formed is of importance. Overall, the work showed that the UV-vis imaging-based platform with an agarose hydrogel mimicking the subcutaneous tissue holds potential in providing bio-relevant and mechanistic information on the phase separation processes of in situ forming implants. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Mapping of information and identification of construction waste at project life cycle

    Science.gov (United States)

    Wibowo, Mochamad Agung; Handayani, Naniek Utami; Nurdiana, Asri; Sholeh, Moh Nur; Pamungkas, Gita Silvia

    2018-03-01

    The development of construction project towards green construction is needed in order to improve the efficiency of construction projects. One that needs to be minimized is construction waste. Construction waste is waste generated from construction project activities, both solid waste and non solid waste. More specifically, the waste happens at every phase of the project life cycle. Project life cycle are the stage of idea, design, construction, and operation/maintenance. Each phase is managed by different stakeholders. Therefore it requires special handling from the involved stakeholders. The objective of the study is to map the information and identify the waste at each phase of the project life cycle. The purpose of mapping is to figure out the process of information and product flow and with its timeline. This mapping used Value Stream Mapping (VSM). Identification of waste was done by distributing questionnaire to respondents to know the waste according to owner, consultant planner, contractor, and supervisory consultant. The result of the study is the mapping of information flow and product flow at the phases of idea, design, construction, and operation/ maintenance.

  5. Connective tissue regeneration in skeletal muscle after eccentric contraction-induced injury.

    Science.gov (United States)

    Mackey, Abigail L; Kjaer, Michael

    2017-03-01

    Human skeletal muscle has the potential to regenerate completely after injury induced under controlled experimental conditions. The events inside the myofibers as they undergo necrosis, followed closely by satellite cell-mediated myogenesis, have been mapped in detail. Much less is known about the adaptation throughout this process of both the connective tissue structures surrounding the myofibers and the fibroblasts, the cells responsible for synthesizing this connective tissue. However, the few studies investigating muscle connective tissue remodeling demonstrate a strong response that appears to be sustained for a long time after the major myofiber responses have subsided. While the use of electrical stimulation to induce eccentric contractions vs. voluntary eccentric contractions appears to lead to a greater extent of myofiber necrosis and regenerative response, this difference is not apparent when the muscle connective tissue responses are compared, although further work is required to confirm this. Pharmacological agents (growth hormone and angiotensin II type I receptor blockers) are considered in the context of accelerating the muscle connective tissue adaptation to loading. Cautioning against this, however, is the association between muscle matrix protein remodeling and protection against reinjury, which suggests that a (so far undefined) period of vulnerability to reinjury may exist during the remodeling phases. The role of individual muscle matrix components and their spatial interaction during adaptation to eccentric contractions is an unexplored field in human skeletal muscle and may provide insight into the optimal timing of rest vs. return to activity after muscle injury. Copyright © 2017 the American Physiological Society.

  6. Spatiotemporal complexity in coupled map lattices

    International Nuclear Information System (INIS)

    Kaneko, Kunihiko

    1986-01-01

    Some spatiotemporal patterns of couple map lattices are presented. The chaotic kink-like motions are shown for the phase motion of the coupled circle lattices. An extension of the couple map lattice approach to Hamiltonian dynamics is briefly reported. An attempt to characterize the high-dimensional attractor by the extension of the correlation dimension is discussed. (author)

  7. A Continuously Updated, Global Land Classification Map, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to demonstrate a fully automatic capability for generating a global, high resolution (30 m) land classification map, with continuous updates from...

  8. Acoustic methods for cavitation mapping in biomedical applications

    Science.gov (United States)

    Wan, M.; Xu, S.; Ding, T.; Hu, H.; Liu, R.; Bai, C.; Lu, S.

    2015-12-01

    In recent years, cavitation is increasingly utilized in a wide range of applications in biomedical field. Monitoring the spatial-temporal evolution of cavitation bubbles is of great significance for efficiency and safety in biomedical applications. In this paper, several acoustic methods for cavitation mapping proposed or modified on the basis of existing work will be presented. The proposed novel ultrasound line-by-line/plane-by-plane method can depict cavitation bubbles distribution with high spatial and temporal resolution and may be developed as a potential standard 2D/3D cavitation field mapping method. The modified ultrafast active cavitation mapping based upon plane wave transmission and reception as well as bubble wavelet and pulse inversion technique can apparently enhance the cavitation to tissue ratio in tissue and further assist in monitoring the cavitation mediated therapy with good spatial and temporal resolution. The methods presented in this paper will be a foundation to promote the research and development of cavitation imaging in non-transparent medium.

  9. Ordered and isomorphic mapping of periodic structures in the parametrically forced logistic map

    Energy Technology Data Exchange (ETDEWEB)

    Maranhão, Dariel M., E-mail: dariel@ifsp.edu.br [Departamento de Ciências e Matemática, Instituto Federal de Educação, Ciência e Tecnologia de São Paulo, São Paulo (Brazil); Diretoria de Informática, Universidade Nove de Julho, São Paulo (Brazil)

    2016-09-23

    Highlights: • A direct description of the internal structure of a periodic window in terms of winding numbers is proposed. • Periodic structures in parameter spaces are mapped in a recurrent and isomorphic way. • Sequences of winding numbers show global and local organization of periodic domains. - Abstract: We investigate the periodic domains found in the parametrically forced logistic map, the classical logistic map when its control parameter changes dynamically. Phase diagrams in two-parameter spaces reveal intricate periodic structures composed of patterns of intersecting superstable orbits curves, defining the cell of a periodic window. Cells appear multifoliated and ordered, and they are isomorphically mapped when one changes the map parameters. Also, we identify the characteristics of simplest cell and apply them to other more complex, discussing how the topography on parameter space is affected. By use of the winding number as defined in periodically forced oscillators, we show that the hierarchical organization of the periodic domains is manifested in global and local scales.

  10. Long Read Alignment with Parallel MapReduce Cloud Platform

    Directory of Open Access Journals (Sweden)

    Ahmed Abdulhakim Al-Absi

    2015-01-01

    Full Text Available Genomic sequence alignment is an important technique to decode genome sequences in bioinformatics. Next-Generation Sequencing technologies produce genomic data of longer reads. Cloud platforms are adopted to address the problems arising from storage and analysis of large genomic data. Existing genes sequencing tools for cloud platforms predominantly consider short read gene sequences and adopt the Hadoop MapReduce framework for computation. However, serial execution of map and reduce phases is a problem in such systems. Therefore, in this paper, we introduce Burrows-Wheeler Aligner’s Smith-Waterman Alignment on Parallel MapReduce (BWASW-PMR cloud platform for long sequence alignment. The proposed cloud platform adopts a widely accepted and accurate BWA-SW algorithm for long sequence alignment. A custom MapReduce platform is developed to overcome the drawbacks of the Hadoop framework. A parallel execution strategy of the MapReduce phases and optimization of Smith-Waterman algorithm are considered. Performance evaluation results exhibit an average speed-up of 6.7 considering BWASW-PMR compared with the state-of-the-art Bwasw-Cloud. An average reduction of 30% in the map phase makespan is reported across all experiments comparing BWASW-PMR with Bwasw-Cloud. Optimization of Smith-Waterman results in reducing the execution time by 91.8%. The experimental study proves the efficiency of BWASW-PMR for aligning long genomic sequences on cloud platforms.

  11. Long Read Alignment with Parallel MapReduce Cloud Platform

    Science.gov (United States)

    Al-Absi, Ahmed Abdulhakim; Kang, Dae-Ki

    2015-01-01

    Genomic sequence alignment is an important technique to decode genome sequences in bioinformatics. Next-Generation Sequencing technologies produce genomic data of longer reads. Cloud platforms are adopted to address the problems arising from storage and analysis of large genomic data. Existing genes sequencing tools for cloud platforms predominantly consider short read gene sequences and adopt the Hadoop MapReduce framework for computation. However, serial execution of map and reduce phases is a problem in such systems. Therefore, in this paper, we introduce Burrows-Wheeler Aligner's Smith-Waterman Alignment on Parallel MapReduce (BWASW-PMR) cloud platform for long sequence alignment. The proposed cloud platform adopts a widely accepted and accurate BWA-SW algorithm for long sequence alignment. A custom MapReduce platform is developed to overcome the drawbacks of the Hadoop framework. A parallel execution strategy of the MapReduce phases and optimization of Smith-Waterman algorithm are considered. Performance evaluation results exhibit an average speed-up of 6.7 considering BWASW-PMR compared with the state-of-the-art Bwasw-Cloud. An average reduction of 30% in the map phase makespan is reported across all experiments comparing BWASW-PMR with Bwasw-Cloud. Optimization of Smith-Waterman results in reducing the execution time by 91.8%. The experimental study proves the efficiency of BWASW-PMR for aligning long genomic sequences on cloud platforms. PMID:26839887

  12. Latin American Centre for Outcome Mapping - Phase II | IDRC ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Final technical report / Latin American Centre for Outcome Mapping (CLAMA) ... Organization for Women in Science for the Developing World (OWSD), IDRC is pleased to ... Sharing opportunities for innovation in climate change adaptation.

  13. Large area synchrotron X-ray fluorescence mapping of biological samples

    International Nuclear Information System (INIS)

    Kempson, I.; Thierry, B.; Smith, E.; Gao, M.; De Jonge, M.

    2014-01-01

    Large area mapping of inorganic material in biological samples has suffered severely from prohibitively long acquisition times. With the advent of new detector technology we can now generate statistically relevant information for studying cell populations, inter-variability and bioinorganic chemistry in large specimen. We have been implementing ultrafast synchrotron-based XRF mapping afforded by the MAIA detector for large area mapping of biological material. For example, a 2.5 million pixel map can be acquired in 3 hours, compared to a typical synchrotron XRF set-up needing over 1 month of uninterrupted beamtime. Of particular focus to us is the fate of metals and nanoparticles in cells, 3D tissue models and animal tissues. The large area scanning has for the first time provided statistically significant information on sufficiently large numbers of cells to provide data on intercellular variability in uptake of nanoparticles. Techniques such as flow cytometry generally require analysis of thousands of cells for statistically meaningful comparison, due to the large degree of variability. Large area XRF now gives comparable information in a quantifiable manner. Furthermore, we can now image localised deposition of nanoparticles in tissues that would be highly improbable to 'find' by typical XRF imaging. In addition, the ultra fast nature also makes it viable to conduct 3D XRF tomography over large dimensions. This technology avails new opportunities in biomonitoring and understanding metal and nanoparticle fate ex-vivo. Following from this is extension to molecular imaging through specific anti-body targeted nanoparticles to label specific tissues and monitor cellular process or biological consequence

  14. High Throughput Petrochronology and Sedimentary Provenance Analysis by Automated Phase Mapping and LAICPMS

    Science.gov (United States)

    Vermeesch, Pieter; Rittner, Martin; Petrou, Ethan; Omma, Jenny; Mattinson, Chris; Garzanti, Eduardo

    2017-11-01

    The first step in most geochronological studies is to extract dateable minerals from the host rock, which is time consuming, removes textural context, and increases the chance for sample cross contamination. We here present a new method to rapidly perform in situ analyses by coupling a fast scanning electron microscope (SEM) with Energy Dispersive X-ray Spectrometer (EDS) to a Laser Ablation Inductively Coupled Plasma Mass Spectrometer (LAICPMS) instrument. Given a polished hand specimen, a petrographic thin section, or a grain mount, Automated Phase Mapping (APM) by SEM/EDS produces chemical and mineralogical maps from which the X-Y coordinates of the datable minerals are extracted. These coordinates are subsequently passed on to the laser ablation system for isotopic analysis. We apply the APM + LAICPMS method to three igneous, metamorphic, and sedimentary case studies. In the first case study, a polished slab of granite from Guernsey was scanned for zircon, producing a 609 ± 8 Ma weighted mean age. The second case study investigates a paragneiss from an ultra high pressure terrane in the north Qaidam terrane (Qinghai, China). One hundred seven small (25 µm) metamorphic zircons were analyzed by LAICPMS to confirm a 419 ± 4 Ma age of peak metamorphism. The third and final case study uses APM + LAICPMS to generate a large provenance data set and trace the provenance of 25 modern sediments from Angola, documenting longshore drift of Orange River sediments over a distance of 1,500 km. These examples demonstrate that APM + LAICPMS is an efficient and cost effective way to improve the quantity and quality of geochronological data.

  15. WE-AB-202-05: Validation of Lung Stress Maps for CT-Ventilation Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Cazoulat, G; Jolly, S; Matuszak, M; Balter, J; Brock, K [University of Michigan, Ann Arbor, MI (United States); Kipritidis, J; Keall, P [University of Sydney, Sydney NSW (Australia); Siva, S; Hofman, M [Division of Radiation Oncology and Cancer Imaging, Peter MacCallum Cancer Centre, Melbourne VIC (Australia)

    2016-06-15

    Purpose: To date, lung CT-ventilation imaging has been based on quantification of local breathing-induced changes in Hounsfield Units (HU) or volume. This work investigates the use of a stress map resulting from a biomechanical deformable image registration (DIR) algorithm as a metric of the ventilation function. Method: Eight lung cancer patients presenting different kinds of ventilation defects were retrospectively analyzed. Additionally, to the 4DCT acquired for radiotherapy planning, five of them had PET and three had SPECT imaging following inhalation of Ga-68 and Tc-99m, respectively. For each patient, the inhale phase of the 4DCT was registered to the exhale phase using Morfeus, a biomechanical DIR algorithm based on the determination of boundary conditions on the lung surfaces and vessel tree. To take into account the heterogeneity of the tissue stiffness in the stress map estimation, each tetrahedral element of the finite-element model was assigned a Young’s modulus ranging from 60kPa to 12MPa, as a function of the HU in the inhale CT. The node displacements and element stresses resulting from the numerical simulation were used to generate three CT-ventilation maps based on: (i) volume changes (Jacobian determinant), (ii) changes in HU, (iii) the maximum principal stress. The voxel-wise correlation between each CT-ventilation map and the PET or SPECT V image was computed in a lung mask. Results: For patients with PET, the mean (min-max) Spearman correlation coefficients r were: 0.33 (0.19–0.45), 0.36 (0.16–0.51) and 0.42 (0.21–0.59) considering the Jacobian, changes in HU and maximum principal stress, respectively. For patients with SPECT V, the mean r were: 0.12 (−0.12–0.43), 0.29 (0.22–0.45) and 0.33 (0.25–0.39). Conclusion: The maximum principal stress maps showed a stronger correlation with the ventilation images than the previously proposed Jacobian or change in HU maps. This metric thus appears promising for CT-ventilation imaging

  16. Extensive cochleotopic mapping of human auditory cortical fields obtained with phase-encoding FMRI.

    Directory of Open Access Journals (Sweden)

    Ella Striem-Amit

    Full Text Available The primary sensory cortices are characterized by a topographical mapping of basic sensory features which is considered to deteriorate in higher-order areas in favor of complex sensory features. Recently, however, retinotopic maps were also discovered in the higher-order visual, parietal and prefrontal cortices. The discovery of these maps enabled the distinction between visual regions, clarified their function and hierarchical processing. Could such extension of topographical mapping to high-order processing regions apply to the auditory modality as well? This question has been studied previously in animal models but only sporadically in humans, whose anatomical and functional organization may differ from that of animals (e.g. unique verbal functions and Heschl's gyrus curvature. Here we applied fMRI spectral analysis to investigate the cochleotopic organization of the human cerebral cortex. We found multiple mirror-symmetric novel cochleotopic maps covering most of the core and high-order human auditory cortex, including regions considered non-cochleotopic, stretching all the way to the superior temporal sulcus. These maps suggest that topographical mapping persists well beyond the auditory core and belt, and that the mirror-symmetry of topographical preferences may be a fundamental principle across sensory modalities.

  17. Polymer scaffolds with no skin-effect for tissue engineering applications fabricated by thermally induced phase separation

    International Nuclear Information System (INIS)

    Kasoju, Naresh; Kubies, Dana; Sedlačík, Tomáš; Kumorek, Marta M.; Rypáček, František; Janoušková, Olga; Koubková, Jana

    2016-01-01

    Thermally induced phase separation (TIPS) based methods are widely used for the fabrication of porous scaffolds for tissue engineering and related applications. However, formation of a less-/non-porous layer at the scaffold’s outer surface at the air–liquid interface, often known as the skin-effect, restricts the cell infiltration inside the scaffold and therefore limits its efficacy. To this end, we demonstrate a TIPS-based process involving the exposure of the just quenched poly(lactide-co-caprolactone):dioxane phases to the pure dioxane for a short time while still being under the quenching strength, herein after termed as the second quenching (2Q). Scanning electron microscopy, mercury intrusion porosimetry and contact angle analysis revealed a direct correlation between the time of 2Q and the gradual disappearance of the skin, followed by the widening of the outer pores and the formation of the fibrous filaments over the surface, with no effect on the internal pore architecture and the overall porosity of scaffolds. The experiments at various quenching temperatures and polymer concentrations revealed the versatility of 2Q in removing the skin. In addition, the in vitro cell culture studies with the human primary fibroblasts showed that the scaffolds prepared by the TIPS based 2Q process, with the optimal exposure time, resulted in a higher cell seeding and viability in contrast to the scaffolds prepared by the regular TIPS. Thus, TIPS including the 2Q step is a facile, versatile and innovative approach to fabricate the polymer scaffolds with a skin-free and fully open porous surface morphology for achieving a better cell response in tissue engineering and related applications. (paper)

  18. Body maps on the human genome.

    Science.gov (United States)

    Cherniak, Christopher; Rodriguez-Esteban, Raul

    2013-12-20

    Chromosomes have territories, or preferred locales, in the cell nucleus. When these sites are taken into account, some large-scale structure of the human genome emerges. The synoptic picture is that genes highly expressed in particular topologically compact tissues are not randomly distributed on the genome. Rather, such tissue-specific genes tend to map somatotopically onto the complete chromosome set. They seem to form a "genome homunculus": a multi-dimensional, genome-wide body representation extending across chromosome territories of the entire spermcell nucleus. The antero-posterior axis of the body significantly corresponds to the head-tail axis of the nucleus, and the dorso-ventral body axis to the central-peripheral nucleus axis. This large-scale genomic structure includes thousands of genes. One rationale for a homuncular genome structure would be to minimize connection costs in genetic networks. Somatotopic maps in cerebral cortex have been reported for over a century.

  19. Performance maps for the control of thermal energy storage

    DEFF Research Database (Denmark)

    Finck, Christian; Li, Rongling; Zeiler, Wim

    2017-01-01

    Predictive control in building energy systems requires the integration of the building, building system, and component dynamics. The prediction accuracy of these dynamics is crucial for practical applications. This paper introduces performance maps for the control of water tanks, phase change mat...... material tanks, and thermochemical material tanks. The results show that these performance maps can fully account for the dynamics of thermal energy storage tanks.......Predictive control in building energy systems requires the integration of the building, building system, and component dynamics. The prediction accuracy of these dynamics is crucial for practical applications. This paper introduces performance maps for the control of water tanks, phase change...

  20. Drainage identification analysis and mapping, phase 2 : technical brief.

    Science.gov (United States)

    2017-01-01

    This research studied, tested and rectified the compatibility issue related to the recent upgrades of : NJDOT vendor inspection software, and uploaded all collected data to make Drainage Identification : Analysis and Mapping System (DIAMS) current an...

  1. Intrinsic functional brain mapping in reconstructed 4D magnetic susceptibility (χ) data space.

    Science.gov (United States)

    Chen, Zikuan; Calhoun, Vince

    2015-02-15

    By solving an inverse problem of T2*-weighted magnetic resonance imaging for a dynamic fMRI study, we reconstruct a 4D magnetic susceptibility source (χ) data space for intrinsic functional mapping. A 4D phase dataset is calculated from a 4D complex fMRI dataset. The background field and phase wrapping effect are removed by a Laplacian technique. A 3D χ source map is reconstructed from a 3D phase image by a computed inverse MRI (CIMRI) scheme. A 4D χ data space is reconstructed by repeating the 3D χ source reconstruction for each time point. A functional map is calculated by a temporal correlation between voxel signals in the 4D χ space and the timecourse of the task paradigm. With a finger-tapping experiment, we obtain two 3D functional mappings in the 4D magnitude data space and in the reconstructed 4D χ data space. We find that the χ-based functional mapping reveals co-occurrence of bidirectional responses in a 3D activation map that is different from the conventional magnitude-based mapping. The χ-based functional mapping can also be achieved by a 3D deconvolution of a phase activation map. Based on a subject experimental comparison, we show that the 4D χ tomography method could produce a similar χ activation map as obtained by the 3D deconvolution method. By removing the dipole effect and other fMRI technological contaminations, 4D χ tomography provides a 4D χ data space that allows a more direct and truthful functional mapping of a brain activity. Published by Elsevier B.V.

  2. Histology-specific therapy for advanced soft tissue sarcoma and benign connective tissue tumors.

    Science.gov (United States)

    Silk, Ann W; Schuetze, Scott M

    2012-09-01

    Molecularly targeted agents have shown activity in soft tissue sarcoma (STS) and benign connective tissue tumors over the past ten years, but response rates differ by histologic subtype. The field of molecularly targeted agents in sarcoma is increasingly complex. Often, clinicians must rely on phase II data or even case series due to the rarity of these diseases. In subtypes with a clear role of specific factors in the pathophysiology of disease, such as giant cell tumor of the bone and diffuse-type tenosynovial giant cell tumor, it is reasonable to treat with newer targeted therapies, when available, in place of chemotherapy when systemic treatment is needed to control disease. In diseases without documented implication of a pathway in disease pathogenesis (e.g. soft tissue sarcoma and vascular endothelial growth factor), clear benefit from drug treatment should be established in randomized phase III trials before implementation into routine clinical practice. Histologic subtype will continue to emerge as a critical factor in treatment selection as we learn more about the molecular drivers of tumor growth and survival in different subtypes. Many of the drugs that have been recently developed affect tumor growth more than survival, therefore progression-free survival may be a more clinically relevant intermediate endpoint than objective response rate using Response Evaluation Criteria In Solid Tumors (RECIST) in early phase sarcoma trials. Because of the rarity of disease and increasing need for multidisciplinary management, patients with connective tissue tumors should be evaluated at a center with expertise in these diseases. Participation in clinical trials, when available, is highly encouraged.

  3. Movie-maps of low-latitude magnetic storm disturbance

    Science.gov (United States)

    Love, Jeffrey J.; Gannon, Jennifer L.

    2010-06-01

    We present 29 movie-maps of low-latitude horizontal-intensity magnetic disturbance for the years 1999-2006: 28 recording magnetic storms and 1 magnetically quiescent period. The movie-maps are derived from magnetic vector time series data collected at up to 25 ground-based observatories. Using a technique similar to that used in the calculation of Dst, a quiet time baseline is subtracted from the time series from each observatory. The remaining disturbance time series are shown in a polar coordinate system that accommodates both Earth rotation and the universal time dependence of magnetospheric disturbance. Each magnetic storm recorded in the movie-maps is different. While some standard interpretations about the storm time equatorial ring current appear to apply to certain moments and certain phases of some storms, the movie-maps also show substantial variety in the local time distribution of low-latitude magnetic disturbance, especially during storm commencements and storm main phases. All movie-maps are available at the U.S. Geological Survey Geomagnetism Program Web site (http://geomag.usgs.gov).

  4. Digital tissue and what it may reveal about the brain.

    Science.gov (United States)

    Morgan, Josh L; Lichtman, Jeff W

    2017-10-30

    Imaging as a means of scientific data storage has evolved rapidly over the past century from hand drawings, to photography, to digital images. Only recently can sufficiently large datasets be acquired, stored, and processed such that tissue digitization can actually reveal more than direct observation of tissue. One field where this transformation is occurring is connectomics: the mapping of neural connections in large volumes of digitized brain tissue.

  5. Fractional Fourier domain optical image hiding using phase retrieval algorithm based on iterative nonlinear double random phase encoding.

    Science.gov (United States)

    Wang, Xiaogang; Chen, Wen; Chen, Xudong

    2014-09-22

    We present a novel image hiding method based on phase retrieval algorithm under the framework of nonlinear double random phase encoding in fractional Fourier domain. Two phase-only masks (POMs) are efficiently determined by using the phase retrieval algorithm, in which two cascaded phase-truncated fractional Fourier transforms (FrFTs) are involved. No undesired information disclosure, post-processing of the POMs or digital inverse computation appears in our proposed method. In order to achieve the reduction in key transmission, a modified image hiding method based on the modified phase retrieval algorithm and logistic map is further proposed in this paper, in which the fractional orders and the parameters with respect to the logistic map are regarded as encryption keys. Numerical results have demonstrated the feasibility and effectiveness of the proposed algorithms.

  6. Quantum baker maps with controlled-not coupling

    International Nuclear Information System (INIS)

    Vallejos, Raul O; Santoro, Pedro R del; Almeida, Alfredo M Ozorio de

    2006-01-01

    The characteristic stretching and squeezing of chaotic motion is linearized within the finite number of phase space domains which subdivide a classical baker map. Tensor products of such maps are also chaotic, but a more interesting generalized baker map arises if the stacking orders for the factor maps are allowed to interact. These maps are readily quantized, in such a way that the stacking interaction is entirely attributed to primary qubits in each map, if each jth subsystem has Hilbert space dimension D j 2 n j . We here study the particular example of two baker maps that interact via a controlled-not interaction, which is a universal gate for quantum computation. Numerical evidence indicates that the control subspace becomes an ideal Markovian environment for the target map in the limit of large Hilbert space dimension

  7. Uncertainty propagation for flood forecasting in the Alps: different views and impacts from MAP D-PHASE

    Directory of Open Access Journals (Sweden)

    M. W. Rotach

    2012-08-01

    Full Text Available D-PHASE was a Forecast Demonstration Project of the World Weather Research Programme (WWRP related to the Mesoscale Alpine Programme (MAP. Its goal was to demonstrate the reliability and quality of operational forecasting of orographically influenced (determined precipitation in the Alps and its consequences on the distribution of run-off characteristics. A special focus was, of course, on heavy-precipitation events.

    The D-PHASE Operations Period (DOP ran from June to November~2007, during which an end-to-end forecasting system was operated covering many individual catchments in the Alps, with their water authorities, civil protection organizations or other end users. The forecasting system's core piece was a Visualization Platform where precipitation and flood warnings from some 30 atmospheric and 7 hydrological models (both deterministic and probabilistic and corresponding model fields were displayed in uniform and comparable formats. Also, meteograms, nowcasting information and end user communication was made available to all the forecasters, users and end users. D-PHASE information was assessed and used by some 50 different groups ranging from atmospheric forecasters to civil protection authorities or water management bodies.

    In the present contribution, D-PHASE is briefly presented along with its outstanding scientific results and, in particular, the lessons learnt with respect to uncertainty propagation. A focus is thereby on the transfer of ensemble prediction information into the hydrological community and its use with respect to other aspects of societal impact. Objective verification of forecast quality is contrasted to subjective quality assessments during the project (end user workshops, questionnaires and some general conclusions concerning forecast demonstration projects are drawn.

  8. Effects of Sleep Deprivation on Phase Synchronization as Assessed by Wavelet Phase Coherence Analysis of Prefrontal Tissue Oxyhemoglobin Signals.

    Science.gov (United States)

    Bu, Lingguo; Zhang, Ming; Li, Jianfeng; Li, Fangyi; Liu, Heshan; Li, Zengyong

    2017-01-01

    To reveal the physiological mechanism of the decline in cognitive function after sleep deprivation, a within-subject study was performed to assess sleep deprivation effects on phase synchronization, as revealed by wavelet phase coherence (WPCO) analysis of prefrontal tissue oxyhemoglobin signals. Twenty subjects (10 male and 10 female, 25.5 ± 3.5 years old) were recruited to participate in two tests: one without sleep deprivation (group A) and the other with 24 h of sleep deprivation (group B). Before the test, each subject underwent a subjective evaluation using visual analog scales. A cognitive task was performed by judging three random numbers. Continuous recordings of the near-infrared spectroscopy (NIRS) signals were obtained from both the left and right prefrontal lobes during rest, task, and post-task periods. The WPCO of cerebral Delta [HbO2] signals were analyzed for these three periods for both groups A and B. Six frequency intervals were defined: I: 0.6-2 Hz (cardiac activity), II: 0.145-0.6 Hz (respiratory activity), III: 0.052-0.145 Hz (myogenic activity), IV: 0.021-0.052 Hz (neurogenic activity), V: 0.0095-0.021 Hz (nitric oxide related endothelial activity) and VI: 0.005-0.0095 Hz (non-nitric oxide related endothelial activity). WPCO in intervals III (F = 5.955, p = 0.02) and V (F = 4.7, p = 0.037) was significantly lower in group B than in group A at rest. During the task period, WPCO in intervals III (F = 5.175, p = 0.029) and IV (F = 4.585, p = 0.039) was significantly lower in group B compared with group A. In the post-task recovery period, the WPCO in interval III (F = 6.125, p = 0.02) was significantly lower in group B compared with group A. Reaction time was significantly prolonged, and the accuracy rate and F1 score both declined after sleep deprivation. The decline in WPCO after sleep deprivation indicates reduced phase synchronization between left and right prefrontal oxyhemoglobin oscillations, which may contribute to the diminished

  9. Identification of QTLs Associated with Callogenesis and Embryogenesis in Oil Palm Using Genetic Linkage Maps Improved with SSR Markers

    Science.gov (United States)

    Ting, Ngoot-Chin; Jansen, Johannes; Nagappan, Jayanthi; Ishak, Zamzuri; Chin, Cheuk-Weng; Tan, Soon-Guan; Cheah, Suan-Choo; Singh, Rajinder

    2013-01-01

    Clonal reproduction of oil palm by means of tissue culture is a very inefficient process. Tissue culturability is known to be genotype dependent with some genotypes being more amenable to tissue culture than others. In this study, genetic linkage maps enriched with simple sequence repeat (SSR) markers were developed for dura (ENL48) and pisifera (ML161), the two fruit forms of oil palm, Elaeis guineensis. The SSR markers were mapped onto earlier reported parental maps based on amplified fragment length polymorphism (AFLP) and restriction fragment length polymorphism (RFLP) markers. The new linkage map of ENL48 contains 148 markers (33 AFLPs, 38 RFLPs and 77 SSRs) in 23 linkage groups (LGs), covering a total map length of 798.0 cM. The ML161 map contains 240 markers (50 AFLPs, 71 RFLPs and 119 SSRs) in 24 LGs covering a total of 1,328.1 cM. Using the improved maps, two quantitative trait loci (QTLs) associated with tissue culturability were identified each for callusing rate and embryogenesis rate. A QTL for callogenesis was identified in LGD4b of ENL48 and explained 17.5% of the phenotypic variation. For embryogenesis rate, a QTL was detected on LGP16b in ML161 and explained 20.1% of the variation. This study is the first attempt to identify QTL associated with tissue culture amenity in oil palm which is an important step towards understanding the molecular processes underlying clonal regeneration of oil palm. PMID:23382832

  10. Comprehensive comparison of large-scale tissue expression datasets

    DEFF Research Database (Denmark)

    Santos Delgado, Alberto; Tsafou, Kalliopi; Stolte, Christian

    2015-01-01

    a comprehensive evaluation of tissue expression data from a variety of experimental techniques and show that these agree surprisingly well with each other and with results from literature curation and text mining. We further found that most datasets support the assumed but not demonstrated distinction between......For tissues to carry out their functions, they rely on the right proteins to be present. Several high-throughput technologies have been used to map out which proteins are expressed in which tissues; however, the data have not previously been systematically compared and integrated. We present......://tissues.jensenlab.org), which makes all the scored and integrated data available through a single user-friendly web interface....

  11. Association between increased epicardial adipose tissue volume and coronary plaque composition

    OpenAIRE

    Yamashita, Kennosuke; Yamamoto, Myong Hwa; Ebara, Seitarou; Okabe, Toshitaka; Saito, Shigeo; Hoshimoto, Koichi; Yakushiji, Tadayuki; Isomura, Naoei; Araki, Hiroshi; Obara, Chiaki; Ochiai, Masahiko

    2013-01-01

    To assess the relationship between epicardial adipose tissue volume (EATV) and plaque vulnerability in significant coronary stenosis using a 40-MHz intravascular ultrasound (IVUS) imaging system (iMap-IVUS), we analyzed 130 consecutive patients with coronary stenosis who underwent dual-source computed tomography (CT) and cardiac catheterization. Culprit lesions were imaged by iMap-IVUS before stenting. The iMAP-IVUS system classified coronary plaque components as fibrous, lipid, necrotic, or ...

  12. Estimation of geometrically undistorted B0 inhomogeneity maps

    International Nuclear Information System (INIS)

    Matakos, A; Balter, J; Cao, Y

    2014-01-01

    Geometric accuracy of MRI is one of the main concerns for its use as a sole image modality in precision radiation therapy (RT) planning. In a state-of-the-art scanner, system level geometric distortions are within acceptable levels for precision RT. However, subject-induced B 0 inhomogeneity may vary substantially, especially in air-tissue interfaces. Recent studies have shown distortion levels of more than 2 mm near the sinus and ear canal are possible due to subject-induced field inhomogeneity. These distortions can be corrected with the use of accurate B 0 inhomogeneity field maps. Most existing methods estimate these field maps from dual gradient-echo (GRE) images acquired at two different echo-times under the assumption that the GRE images are practically undistorted. However distortion that may exist in the GRE images can result in estimated field maps that are distorted in both geometry and intensity, leading to inaccurate correction of clinical images. This work proposes a method for estimating undistorted field maps from GRE acquisitions using an iterative joint estimation technique. The proposed method yields geometrically corrected GRE images and undistorted field maps that can also be used for the correction of images acquired by other sequences. The proposed method is validated through simulation, phantom experiments and applied to patient data. Our simulation results show that our method reduces the root-mean-squared error of the estimated field map from the ground truth by ten-fold compared to the distorted field map. Both the geometric distortion and the intensity corruption (artifact) in the images caused by the B 0 field inhomogeneity are corrected almost completely. Our phantom experiment showed improvement in the geometric correction of approximately 1 mm at an air-water interface using the undistorted field map compared to using a distorted field map. The proposed method for undistorted field map estimation can lead to improved geometric

  13. Estimation of geometrically undistorted B0 inhomogeneity maps

    Science.gov (United States)

    Matakos, A.; Balter, J.; Cao, Y.

    2014-09-01

    Geometric accuracy of MRI is one of the main concerns for its use as a sole image modality in precision radiation therapy (RT) planning. In a state-of-the-art scanner, system level geometric distortions are within acceptable levels for precision RT. However, subject-induced B0 inhomogeneity may vary substantially, especially in air-tissue interfaces. Recent studies have shown distortion levels of more than 2 mm near the sinus and ear canal are possible due to subject-induced field inhomogeneity. These distortions can be corrected with the use of accurate B0 inhomogeneity field maps. Most existing methods estimate these field maps from dual gradient-echo (GRE) images acquired at two different echo-times under the assumption that the GRE images are practically undistorted. However distortion that may exist in the GRE images can result in estimated field maps that are distorted in both geometry and intensity, leading to inaccurate correction of clinical images. This work proposes a method for estimating undistorted field maps from GRE acquisitions using an iterative joint estimation technique. The proposed method yields geometrically corrected GRE images and undistorted field maps that can also be used for the correction of images acquired by other sequences. The proposed method is validated through simulation, phantom experiments and applied to patient data. Our simulation results show that our method reduces the root-mean-squared error of the estimated field map from the ground truth by ten-fold compared to the distorted field map. Both the geometric distortion and the intensity corruption (artifact) in the images caused by the B0 field inhomogeneity are corrected almost completely. Our phantom experiment showed improvement in the geometric correction of approximately 1 mm at an air-water interface using the undistorted field map compared to using a distorted field map. The proposed method for undistorted field map estimation can lead to improved geometric

  14. Automated tissue classification of pediatric brains from magnetic resonance images using age-specific atlases

    Science.gov (United States)

    Metzger, Andrew; Benavides, Amanda; Nopoulos, Peg; Magnotta, Vincent

    2016-03-01

    The goal of this project was to develop two age appropriate atlases (neonatal and one year old) that account for the rapid growth and maturational changes that occur during early development. Tissue maps from this age group were initially created by manually correcting the resulting tissue maps after applying an expectation maximization (EM) algorithm and an adult atlas to pediatric subjects. The EM algorithm classified each voxel into one of ten possible tissue types including several subcortical structures. This was followed by a novel level set segmentation designed to improve differentiation between distal cortical gray matter and white matter. To minimize the req uired manual corrections, the adult atlas was registered to the pediatric scans using high -dimensional, symmetric image normalization (SyN) registration. The subject images were then mapped to an age specific atlas space, again using SyN registration, and the resulting transformation applied to the manually corrected tissue maps. The individual maps were averaged in the age specific atlas space and blurred to generate the age appropriate anatomical priors. The resulting anatomical priors were then used by the EM algorithm to re-segment the initial training set as well as an independent testing set. The results from the adult and age-specific anatomical priors were compared to the manually corrected results. The age appropriate atlas provided superior results as compared to the adult atlas. The image analysis pipeline used in this work was built using the open source software package BRAINSTools.

  15. Fluence map segmentation

    International Nuclear Information System (INIS)

    Rosenwald, J.-C.

    2008-01-01

    The lecture addressed the following topics: 'Interpreting' the fluence map; The sequencer; Reasons for difference between desired and actual fluence map; Principle of 'Step and Shoot' segmentation; Large number of solutions for given fluence map; Optimizing 'step and shoot' segmentation; The interdigitation constraint; Main algorithms; Conclusions on segmentation algorithms (static mode); Optimizing intensity levels and monitor units; Sliding window sequencing; Synchronization to avoid the tongue-and-groove effect; Accounting for physical characteristics of MLC; Importance of corrections for leaf transmission and offset; Accounting for MLC mechanical constraints; The 'complexity' factor; Incorporating the sequencing into optimization algorithm; Data transfer to the treatment machine; Interface between R and V and accelerator; and Conclusions on fluence map segmentation (Segmentation is part of the overall inverse planning procedure; 'Step and Shoot' and 'Dynamic' options are available for most TPS (depending on accelerator model; The segmentation phase tends to come into the optimization loop; The physical characteristics of the MLC have a large influence on final dose distribution; The IMRT plans (MU and relative dose distribution) must be carefully validated). (P.A.)

  16. The significance of monitoring sex hormones levels after ovarian tissue auto-transplantation

    International Nuclear Information System (INIS)

    Wang Qiuwei; Xu Peizhen; Yu Bin; Zhou Hong

    2003-01-01

    Objective: To evaluate the significance of monitoring serum sex hormones levels after ovarian tissue auto-transplantation. Methods: Twenty-five patients with stage IV recurrent endometriosis after one or two times of conservative surgeries underwent radical surgery. Their ovarian tissue fragments were transplanted to greater omentum. Serum follicle-stimulation hormone (FSH), Luteinizing hormone (LH) and estradiol (E 2 ) levels were measured monthly since fourth month post-operatively. After E 2 was increased, based body temperature was measured and vaginal hormone cytology was examined weekly for maturation index (MI) to assess the ovulatory phase and luteal phase in those with viable ovarian tissues. Serum levels of FSH, LH and E 2 in ovulatory phase and luteal phase were determined 20 women with viable ovarian tissues for three cycles as well as in 20 normal sexually mature women and 20 operative menopausal women. Results: There were 12 cases who had increasing of E 2 at four months post operatively and 8 cases more at six months. The other 5 cases with low serum E 2 levels and high FSH and LH levels at 12 months were designated as failures. The survival rate of transplanted ovarian tissue was 80.0%. There were no significant differences of the serum FSH, LH and E 2 levels in ovulatory phase and luteal phase between women with viable grafted ovarian tissues and normal sexually mature women. Conclusion: Monitoring of sex hormones is a good means to assess the viability of the transplanted ovarian tissue fragments

  17. Neural dynamics of the cognitive map in the hippocampus.

    Science.gov (United States)

    Wagatsuma, Hiroaki; Yamaguchi, Yoko

    2007-06-01

    The rodent hippocampus has been thought to represent the spatial environment as a cognitive map. In the classical theory, the cognitive map has been explained as a consequence of the fact that different spatial regions are assigned to different cell populations in the framework of rate coding. Recently, the relation between place cell firing and local field oscillation theta in terms of theta phase precession was experimentally discovered and suggested as a temporal coding mechanism leading to memory formation of behavioral sequences accompanied with asymmetric Hebbian plasticity. The cognitive map theory is apparently outside of the sequence memory view. Therefore, theoretical analysis is necessary to consider the biological neural dynamics for the sequence encoding of the memory of behavioral sequences, providing the cognitive map formation. In this article, we summarize the theoretical neural dynamics of the real-time sequence encoding by theta phase precession, called theta phase coding, and review a series of theoretical models with the theta phase coding that we previously reported. With respect to memory encoding functions, instantaneous memory formation of one-time experience was first demonstrated, and then the ability of integration of memories of behavioral sequences into a network of the cognitive map was shown. In terms of memory retrieval functions, theta phase coding enables the hippocampus to represent the spatial location in the current behavioral context even with ambiguous sensory input when multiple sequences were coded. Finally, for utilization, retrieved temporal sequences in the hippocampus can be available for action selection, through the process of reverting theta rhythm-dependent activities to information in the behavioral time scale. This theoretical approach allows us to investigate how the behavioral sequences are encoded, updated, retrieved and used in the hippocampus, as the real-time interaction with the external environment. It may

  18. Bladder tissue engineering through nanotechnology.

    Science.gov (United States)

    Harrington, Daniel A; Sharma, Arun K; Erickson, Bradley A; Cheng, Earl Y

    2008-08-01

    The field of tissue engineering has developed in phases: initially researchers searched for "inert" biomaterials to act solely as replacement structures in the body. Then, they explored biodegradable scaffolds--both naturally derived and synthetic--for the temporary support of growing tissues. Now, a third phase of tissue engineering has developed, through the subcategory of "regenerative medicine." This renewed focus toward control over tissue morphology and cell phenotype requires proportional advances in scaffold design. Discoveries in nanotechnology have driven both our understanding of cell-substrate interactions, and our ability to influence them. By operating at the size regime of proteins themselves, nanotechnology gives us the opportunity to directly speak the language of cells, through reliable, repeatable creation of nanoscale features. Understanding the synthesis of nanoscale materials, via "top-down" and "bottom-up" strategies, allows researchers to assess the capabilities and limits inherent in both techniques. Urology research as a whole, and bladder regeneration in particular, are well-positioned to benefit from such advances, since our present technology has yet to reach the end goal of functional bladder restoration. In this article, we discuss the current applications of nanoscale materials to bladder tissue engineering, and encourage researchers to explore these interdisciplinary technologies now, or risk playing catch-up in the future.

  19. Detection, mapping, and quantification of single walled carbon nanotubes in histological specimens with photoacoustic microscopy.

    Science.gov (United States)

    Avti, Pramod K; Hu, Song; Favazza, Christopher; Mikos, Antonios G; Jansen, John A; Shroyer, Kenneth R; Wang, Lihong V; Sitharaman, Balaji

    2012-01-01

    In the present study, the efficacy of multi-scale photoacoustic microscopy (PAM) was investigated to detect, map, and quantify trace amounts [nanograms (ng) to micrograms (µg)] of SWCNTs in a variety of histological tissue specimens consisting of cancer and benign tissue biopsies (histological specimens from implanted tissue engineering scaffolds). Optical-resolution (OR) and acoustic-resolution (AR)--Photoacoustic microscopy (PAM) was employed to detect, map and quantify the SWCNTs in a variety of tissue histological specimens and compared with other optical techniques (bright-field optical microscopy, Raman microscopy, near infrared (NIR) fluorescence microscopy). Both optical-resolution and acoustic-resolution PAM, allow the detection and quantification of SWCNTs in histological specimens with scalable spatial resolution and depth penetration. The noise-equivalent detection sensitivity to SWCNTs in the specimens was calculated to be as low as ∼7 pg. Image processing analysis further allowed the mapping, distribution, and quantification of the SWCNTs in the histological sections. The results demonstrate the potential of PAM as a promising imaging technique to detect, map, and quantify SWCNTs in histological specimens, and could complement the capabilities of current optical and electron microscopy techniques in the analysis of histological specimens containing SWCNTs.

  20. Detection, mapping, and quantification of single walled carbon nanotubes in histological specimens with photoacoustic microscopy.

    Directory of Open Access Journals (Sweden)

    Pramod K Avti

    Full Text Available In the present study, the efficacy of multi-scale photoacoustic microscopy (PAM was investigated to detect, map, and quantify trace amounts [nanograms (ng to micrograms (µg] of SWCNTs in a variety of histological tissue specimens consisting of cancer and benign tissue biopsies (histological specimens from implanted tissue engineering scaffolds.Optical-resolution (OR and acoustic-resolution (AR--Photoacoustic microscopy (PAM was employed to detect, map and quantify the SWCNTs in a variety of tissue histological specimens and compared with other optical techniques (bright-field optical microscopy, Raman microscopy, near infrared (NIR fluorescence microscopy.Both optical-resolution and acoustic-resolution PAM, allow the detection and quantification of SWCNTs in histological specimens with scalable spatial resolution and depth penetration. The noise-equivalent detection sensitivity to SWCNTs in the specimens was calculated to be as low as ∼7 pg. Image processing analysis further allowed the mapping, distribution, and quantification of the SWCNTs in the histological sections.The results demonstrate the potential of PAM as a promising imaging technique to detect, map, and quantify SWCNTs in histological specimens, and could complement the capabilities of current optical and electron microscopy techniques in the analysis of histological specimens containing SWCNTs.

  1. Citygml Modelling for Singapore 3d National Mapping

    Science.gov (United States)

    Soon, K. H.; Khoo, V. H. S.

    2017-10-01

    Since 2014, the Land Survey Division of Singapore Land Authority (SLA) has spearheaded a Whole-of-Government (WOG) 3D mapping project to create and maintain a 3D national map for Singapore. The implementation of the project is divided into two phases. The first phase of the project, which was based on airborne data collection, has produced 3D models for Relief, Building, Vegetation and Waterbody. This part of the work was completed in 2016. To complement the first phase, the second phase used mobile imaging and scanning technique. This phase is targeted to be completed by the mid of 2017 and is creating 3D models for Transportation, CityFurniture, Bridge and Tunnel. The project has extensively adopted the Open Geospatial Consortium (OGC)'s CityGML standard. Out of 10 currently supported thematic modules in CityGML 2.0, the project has implemented 8. The paper describes the adoption of CityGML in the project, and discusses challenges, data validations and management of the models.

  2. Three-dimensional optical coherence micro-elastography of skeletal muscle tissue

    OpenAIRE

    Chin, Lixin; Kennedy, Brendan F.; Kennedy, Kelsey M.; Wijesinghe, Philip; Pinniger, Gavin J.; Terrill, Jessica R.; McLaughlin, Robert A.; Sampson, David D.

    2014-01-01

    In many muscle pathologies, impairment of skeletal muscle function is closely linked to changes in the mechanical properties of the muscle constituents. Optical coherence micro-elastography (OCME) uses optical coherence tomography (OCT) imaging of tissue under a quasi-static, compressive mechanical load to map variations in tissue mechanical properties on the micro-scale. We present the first study of OCME on skeletal muscle tissue. We show that this technique can resolve features of muscle t...

  3. Determination of composition and structure of spongy bone tissue in human head of femur by Raman spectral mapping.

    Science.gov (United States)

    Kozielski, M; Buchwald, T; Szybowicz, M; Błaszczak, Z; Piotrowski, A; Ciesielczyk, B

    2011-07-01

    Biomechanical properties of bone depend on the composition and organization of collagen fibers. In this study, Raman microspectroscopy was employed to determine the content of mineral and organic constituents and orientation of collagen fibers in spongy bone in the human head of femur at the microstructural level. Changes in composition and structure of trabecula were illustrated using Raman spectral mapping. The polarized Raman spectra permit separate analysis of local variations in orientation and composition. The ratios of ν₂PO₄³⁻/Amide III, ν₄PO₄³⁻/Amide III and ν₁CO₃²⁻/ν₂PO₄³⁻ are used to describe relative amounts of spongy bone components. The ν₁PO₄³⁻/Amide I ratio is quite susceptible to orientation effect and brings information on collagen fibers orientation. The results presented illustrate the versatility of the Raman method in the study of bone tissue. The study permits better understanding of bone physiology and evaluation of the biomechanical properties of bone.

  4. Isolation of Mycobacterium avium subsp paratuberculosis (Map) from feral cats on a dairy farm with Map-infected cattle.

    Science.gov (United States)

    Palmer, Mitchell V; Stoffregen, William C; Carpenter, Jeremy G; Stabel, Judith R

    2005-07-01

    Paratuberculosis is an economically important disease of dairy cattle caused by Mycobacterium avium subsp. paratuberculosis (Map). The role of nonruminant, nondomestic animals in the epidemiology of paratuberculosis in cattle is unclear. To examine nonruminant, nondomestic animals for the presence of Map, 25 feral cats, nine mice (species unknown), eight rabbits (Sylvilagus floridanus), six raccoons (Procyon lotor), and three opossums (Didelphis virginiana) were collected from a mid-western dairy with known Map-infected cattle. Mycobacterium avium subsp. paratuberculosis was isolated from the mesenteric lymph node from seven of 25 (28%) feral cats. Ileum was culture-positive for three of these seven cats, and an isolation of Map was also made from the ileum of one of nine (11%) mice. Tissue samples from other species were negative as determined by Map culture; microscopic lesions consistent with paratuberculosis were not seen in any animal. Restriction fragment polymorphism analysis of isolates from cats and dairy cattle suggest interspecies transmission. The means by which interspecies transmission occurred may be through ingestion of Map-contaminated feces or waste milk or through ingestion of Map-infected prey. Shedding of Map from infected cats was not evaluated. The epidemiologic role of Map-infected feral cats on dairy farms requires further investigation.

  5. Flow regime mapping of vertical two-phase downflow in a ribbed annulus

    International Nuclear Information System (INIS)

    Kielpinski, A.L.

    1992-01-01

    Two-phase flow regimes have been mapped for vertical, cocurrent downflow in a narrow annulus which is partially segmented by the presence of longitudinal ribs. This geometry and flow condition has application to the analysis of a Large-Break Loss of Coolant Accident (LB-LOCA) in the production K-Reactor at the Savannah River Site (SRS). The ribbed annular geometry, particularly the presence of non-sealing ribs, gives rise to some unique phenomenological features. The flow behavior is influenced by the partial segmentation of the annulus into four quadrants or subchannels. A random element is induced by the natural bowing of the slender tubes; the width of the azimuthal flow path between two subchannels at a given axial location is indeterminate, and can take on any value between zero and the maximum clearance of 7.6 x l0 -4 m. When the rib gap is zero at a given location, it is at a maximum 180P away at the same axial location. The range of rib gaps is spanned in a single test section, as it would be also in a reactor assembly. As a result of these effects, flow regime maps obtained by other researchers for downflow in annuli are not accurate for defining flow regimes in a ribbed annulus. Flow regime transitions similar to those noted by, e.g., Bamea, were observed; the locations of these transitions were displaced with respect to the transition equations derived by Bamea. Experimental bubble rise velocity measurements were also obtained in the same test section. The bubble rise velocities were much higher than expected from the theory developed for slug bubbles in tubes, unribbed annuli, and rectangular channels. An elliptical-cap bubble rises faster than a slug bubble of the same area. Large, slug-shaped bubbles injected into the test section were observed to reduce in size as they rose, due to interaction with a longitudinal rib. They thereby adopted a shape more like an elliptical-cap bubble, hence rising faster than the original slug bubble

  6. Cellular composition of granulomatous lesions in gut-associated lymphoid tissues of goats during the first year after experimental infection with Mycobacterium avium subsp. paratuberculosis.

    Science.gov (United States)

    Krüger, C; Köhler, H; Liebler-Tenorio, E M

    2015-01-15

    Mycobacterium avium subsp. paratuberculosis (MAP) causes lesions in naturally and experimentally infected ruminants which greatly differ in severity, cellular composition and number of mycobacteria. Morphologically distinct lesions are already found during the clinically inapparent phase of infection. The complex local host response and number of MAP were characterized at the initial sites of lesions, organized gut-associated lymphoid tissue, in experimentally infected goats. Tissues were collected at 3, 6, 9 and 12 month post-inoculation (mpi) from goat kids that had orally received 10 times 10mg of bacterial wet mass of MAP (JII-1961). The cellular composition of lesions in Peyer's patches in the jejunum and next to the ileocecal valve was evaluated in 21 MAP-inoculated goats, where lesions were compared with unaltered tissue of six control goats. CD68+, CD4+, CD8+, γδ T lymphocytes, B lymphocytes and plasma cells, MHC class II+ and CD25+ cells were demonstrated by immunohistochemistry in serial cryostat sections. At 3 mpi, extensive granulomatous infiltrates predominated, consisting of numerous epitheloid cells admixed with many CD4 and γδ T lymphocytes. Only single MAP were detected. This indicates a strong cellular immune reaction able to control MAP infection. γδ T lymphocytes were markedly increased in this type of lesion which may reflect their important role early in the pathogenesis of paratuberculosis. At 9 and 12 mpi, divergent lesions were observed which may reflect different outcomes of host-pathogen interactions. In five goats, minimal granulomatous lesions were surrounded by extensive lymphoplasmacytic infiltrates and no MAP were detected by immunohistochemistry. This was interpreted as effective host response that was able to eliminate MAP locally. In three goats, decreased numbers of lymphocytes, but extensive granulomatous infiltrates with numerous epitheloid cells containing increased numbers of mycobacteria were seen. This shift of the

  7. Transitions from phase-locked dynamics to chaos in a piecewise-linear map

    DEFF Research Database (Denmark)

    Zhusubaliyev, Z.T.; Mosekilde, Erik; De, S.

    2008-01-01

    place via border-collision fold bifurcations. We examine the transition to chaos through torus destruction in such maps. Considering a piecewise-linear normal-form map we show that this transition, by virtue of the interplay of border-collision bifurcations with period-doubling and homoclinic...

  8. Brain Oxygen Optimization in Severe Traumatic Brain Injury Phase-II: A Phase II Randomized Trial.

    Science.gov (United States)

    Okonkwo, David O; Shutter, Lori A; Moore, Carol; Temkin, Nancy R; Puccio, Ava M; Madden, Christopher J; Andaluz, Norberto; Chesnut, Randall M; Bullock, M Ross; Grant, Gerald A; McGregor, John; Weaver, Michael; Jallo, Jack; LeRoux, Peter D; Moberg, Dick; Barber, Jason; Lazaridis, Christos; Diaz-Arrastia, Ramon R

    2017-11-01

    A relationship between reduced brain tissue oxygenation and poor outcome following severe traumatic brain injury has been reported in observational studies. We designed a Phase II trial to assess whether a neurocritical care management protocol could improve brain tissue oxygenation levels in patients with severe traumatic brain injury and the feasibility of a Phase III efficacy study. Randomized prospective clinical trial. Ten ICUs in the United States. One hundred nineteen severe traumatic brain injury patients. Patients were randomized to treatment protocol based on intracranial pressure plus brain tissue oxygenation monitoring versus intracranial pressure monitoring alone. Brain tissue oxygenation data were recorded in the intracranial pressure -only group in blinded fashion. Tiered interventions in each arm were specified and impact on intracranial pressure and brain tissue oxygenation measured. Monitors were removed if values were normal for 48 hours consecutively, or after 5 days. Outcome was measured at 6 months using the Glasgow Outcome Scale-Extended. A management protocol based on brain tissue oxygenation and intracranial pressure monitoring reduced the proportion of time with brain tissue hypoxia after severe traumatic brain injury (0.45 in intracranial pressure-only group and 0.16 in intracranial pressure plus brain tissue oxygenation group; p injury after severe traumatic brain injury based on brain tissue oxygenation and intracranial pressure values was consistent with reduced mortality and increased proportions of patients with good recovery compared with intracranial pressure-only management; however, the study was not powered for clinical efficacy. Management of severe traumatic brain injury informed by multimodal intracranial pressure and brain tissue oxygenation monitoring reduced brain tissue hypoxia with a trend toward lower mortality and more favorable outcomes than intracranial pressure-only treatment. A Phase III randomized trial to assess

  9. Microgravity Two-Phase Flow Transition

    Science.gov (United States)

    Parang, M.; Chao, D.

    1999-01-01

    Two-phase flows under microgravity condition find a large number of important applications in fluid handling and storage, and spacecraft thermal management. Specifically, under microgravity condition heat transfer between heat exchanger surfaces and fluids depend critically on the distribution and interaction between different fluid phases which are often qualitatively different from the gravity-based systems. Heat transfer and flow analysis in two-phase flows under these conditions require a clear understanding of the flow pattern transition and development of appropriate dimensionless scales for its modeling and prediction. The physics of this flow is however very complex and remains poorly understood. This has led to various inadequacies in flow and heat transfer modeling and has made prediction of flow transition difficult in engineering design of efficient thermal and flow systems. In the present study the available published data for flow transition under microgravity condition are considered for mapping. The transition from slug to annular flow and from bubbly to slug flow are mapped using dimensionless variable combination developed in a previous study by the authors. The result indicate that the new maps describe the flow transitions reasonably well over the range of the data available. The transition maps are examined and the results are discussed in relation to the presumed balance of forces and flow dynamics. It is suggested that further evaluation of the proposed flow and transition mapping will require a wider range of microgravity data expected to be made available in future studies.

  10. Assessment of amide I spectroscopic maps for a gas-phase peptide using IR-UV double-resonance spectroscopy and density functional theory calculations

    Energy Technology Data Exchange (ETDEWEB)

    Carr, J. K.; Roy, S.; Skinner, J. L. [Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin, Madison, Wisconsin 53706 (United States); Zabuga, A. V.; Rizzo, T. R. [Laboratoire de Chimie Physique Moleculaire, Ecole Polytechnique Fédérale de Lausanne, EPFL SB ISIC LCPM, Station 6, CH-1015 Lausanne (Switzerland)

    2014-06-14

    The spectroscopy of amide I vibrations has become a powerful tool for exploring protein structure and dynamics. To help with spectral interpretation, it is often useful to perform molecular dynamics (MD) simulations. To connect spectroscopic experiments to simulations in an efficient manner, several researchers have proposed “maps,” which relate observables in classical MD simulations to quantum spectroscopic variables. It can be difficult to discern whether errors in the theoretical results (compared to experiment) arise from inaccuracies in the MD trajectories or in the maps themselves. In this work, we evaluate spectroscopic maps independently from MD simulations by comparing experimental and theoretical spectra for a single conformation of the α-helical model peptide Ac-Phe-(Ala){sub 5}-Lys-H{sup +} in the gas phase. Conformation-specific experimental spectra are obtained for the unlabeled peptide and for several singly and doubly {sup 13}C-labeled variants using infrared-ultraviolet double-resonance spectroscopy, and these spectra are found to be well-modeled by density functional theory (DFT) calculations at the B3LYP/6-31G** level. We then compare DFT results for the deuterated and {sup 13}C{sup 18}O-labeled peptide with those from spectroscopic maps developed and used previously by the Skinner group. We find that the maps are typically accurate to within a few cm{sup −1} for both frequencies and couplings, having larger errors only for the frequencies of terminal amides.

  11. Assessment of amide I spectroscopic maps for a gas-phase peptide using IR-UV double-resonance spectroscopy and density functional theory calculations

    Science.gov (United States)

    Carr, J. K.; Zabuga, A. V.; Roy, S.; Rizzo, T. R.; Skinner, J. L.

    2014-01-01

    The spectroscopy of amide I vibrations has become a powerful tool for exploring protein structure and dynamics. To help with spectral interpretation, it is often useful to perform molecular dynamics (MD) simulations. To connect spectroscopic experiments to simulations in an efficient manner, several researchers have proposed “maps,” which relate observables in classical MD simulations to quantum spectroscopic variables. It can be difficult to discern whether errors in the theoretical results (compared to experiment) arise from inaccuracies in the MD trajectories or in the maps themselves. In this work, we evaluate spectroscopic maps independently from MD simulations by comparing experimental and theoretical spectra for a single conformation of the α-helical model peptide Ac-Phe-(Ala)5-Lys-H+ in the gas phase. Conformation-specific experimental spectra are obtained for the unlabeled peptide and for several singly and doubly 13C-labeled variants using infrared-ultraviolet double-resonance spectroscopy, and these spectra are found to be well-modeled by density functional theory (DFT) calculations at the B3LYP/6-31G** level. We then compare DFT results for the deuterated and 13C18O-labeled peptide with those from spectroscopic maps developed and used previously by the Skinner group. We find that the maps are typically accurate to within a few cm−1 for both frequencies and couplings, having larger errors only for the frequencies of terminal amides. PMID:24929378

  12. Assessment of amide I spectroscopic maps for a gas-phase peptide using IR-UV double-resonance spectroscopy and density functional theory calculations

    International Nuclear Information System (INIS)

    Carr, J. K.; Roy, S.; Skinner, J. L.; Zabuga, A. V.; Rizzo, T. R.

    2014-01-01

    The spectroscopy of amide I vibrations has become a powerful tool for exploring protein structure and dynamics. To help with spectral interpretation, it is often useful to perform molecular dynamics (MD) simulations. To connect spectroscopic experiments to simulations in an efficient manner, several researchers have proposed “maps,” which relate observables in classical MD simulations to quantum spectroscopic variables. It can be difficult to discern whether errors in the theoretical results (compared to experiment) arise from inaccuracies in the MD trajectories or in the maps themselves. In this work, we evaluate spectroscopic maps independently from MD simulations by comparing experimental and theoretical spectra for a single conformation of the α-helical model peptide Ac-Phe-(Ala) 5 -Lys-H + in the gas phase. Conformation-specific experimental spectra are obtained for the unlabeled peptide and for several singly and doubly 13 C-labeled variants using infrared-ultraviolet double-resonance spectroscopy, and these spectra are found to be well-modeled by density functional theory (DFT) calculations at the B3LYP/6-31G** level. We then compare DFT results for the deuterated and 13 C 18 O-labeled peptide with those from spectroscopic maps developed and used previously by the Skinner group. We find that the maps are typically accurate to within a few cm −1 for both frequencies and couplings, having larger errors only for the frequencies of terminal amides

  13. Left ventricular diastolic dyssynchrony assessed with phase analysis of gated myocardial perfusion SPECT: a comparison with tissue Doppler imaging

    International Nuclear Information System (INIS)

    Boogers, Mark J.; Veltman, Caroline E.; Chen, Ji; Garcia, Ernest V.; Bommel, Rutger J. van; Mooyaart, Eline A.Q.; Wall, Ernst E. van der; Schalij, Martin J.; Bax, Jeroen J.; Delgado, Victoria; Younis, Imad Al; Hiel, Bernies van der; Dibbets-Schneider, Petra

    2011-01-01

    The aim of the current study was to evaluate the feasibility of phase analysis on gated myocardial perfusion SPECT (GMPS) for the assessment of left ventricular (LV) diastolic dyssynchrony in a head-to-head comparison with tissue Doppler imaging (TDI). The population consisted of patients with end-stage heart failure of New York Heart Association functional class III or IV with a reduced LV ejection fraction of ≤35%. LV diastolic dyssynchrony was calculated using TDI as the maximal time delay between early peak diastolic velocities of two opposing left ventricle walls (diastolic mechanical delay). Significant LV diastolic dyssynchrony was defined as a diastolic mechanical delay of >55 ms on TDI. Furthermore, phase analysis on GMPS was performed to evaluate LV diastolic dyssynchrony; diastolic phase standard deviation (SD) and histogram bandwidth (HBW) were used as markers of LV diastolic dyssynchrony. A total of 150 patients (114 men, mean age 66.0 ± 10.4 years) with end-stage heart failure were enrolled. Both diastolic phase SD (r = 0.81, p 55 ms) showed significantly larger diastolic phase SD (68.1 ± 13.4 vs. 40.7 ± 14.0 , p < 0.01) and diastolic HBW (230.6 ± 54.3 vs. 129.0 ± 55.6 , p < 0.01) as compared to patients without LV diastolic dyssynchrony on TDI (≤55 ms). Finally, phase analysis on GMPS showed a good intra- and interobserver reproducibility for the determination of diastolic phase SD (ICC 0.97 and 0.88) and diastolic HBW (ICC 0.98 and 0.93). Phase analysis on GMPS showed good correlations with TDI for the assessment of LV diastolic dyssynchrony. (orig.)

  14. Quantum revivals, geometric phases and circle map recurrences

    International Nuclear Information System (INIS)

    Seshadri, S.; Lakshmibala, S.; Balakrishnan, V.

    1999-01-01

    Revivals of the coherent states of a deformed, adiabatically and cyclically varying oscillator Hamiltonian are examined. The revival time distribution is exactly that of Poincare recurrences for a rotation map: only three distinct revival times can occur, with specified weights. A link is thus established between quantum revivals and recurrences in a coarse-grained discrete-time dynamical system. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  15. Identification of QTLs associated with callogenesis and embryogenesis in oil palm using genetic linkage maps improved with SSR markers.

    Directory of Open Access Journals (Sweden)

    Ngoot-Chin Ting

    Full Text Available Clonal reproduction of oil palm by means of tissue culture is a very inefficient process. Tissue culturability is known to be genotype dependent with some genotypes being more amenable to tissue culture than others. In this study, genetic linkage maps enriched with simple sequence repeat (SSR markers were developed for dura (ENL48 and pisifera (ML161, the two fruit forms of oil palm, Elaeis guineensis. The SSR markers were mapped onto earlier reported parental maps based on amplified fragment length polymorphism (AFLP and restriction fragment length polymorphism (RFLP markers. The new linkage map of ENL48 contains 148 markers (33 AFLPs, 38 RFLPs and 77 SSRs in 23 linkage groups (LGs, covering a total map length of 798.0 cM. The ML161 map contains 240 markers (50 AFLPs, 71 RFLPs and 119 SSRs in 24 LGs covering a total of 1,328.1 cM. Using the improved maps, two quantitative trait loci (QTLs associated with tissue culturability were identified each for callusing rate and embryogenesis rate. A QTL for callogenesis was identified in LGD4b of ENL48 and explained 17.5% of the phenotypic variation. For embryogenesis rate, a QTL was detected on LGP16b in ML161 and explained 20.1% of the variation. This study is the first attempt to identify QTL associated with tissue culture amenity in oil palm which is an important step towards understanding the molecular processes underlying clonal regeneration of oil palm.

  16. Josephson junctions and circle maps

    Energy Technology Data Exchange (ETDEWEB)

    Bak, P; Bohr, T; Jensen, M H; Christiansen, P V

    1984-01-01

    The return map of a differential equation for the current driven Josephson junction, or the damped driven pendulum, is shown numerically to be a circle map. Phase locking, noise and hysteresis, can thus be understood in a simple and coherent way. The transition to chaos is related to the development of a cubic inflection point. Recent theoretical results on universal behavior at the transition to chaos can readily be checked experimentally by studying I-V characteristics. 17 references, 1 figure.

  17. Taurine content of tissues of irradiated rats

    International Nuclear Information System (INIS)

    Akhalaya, M.Ya.; Bogatyrev, G.P.; Kudryashov, Yu.B.; Yartsev, E.I.

    1976-01-01

    The taurine content of tissues (liver, stomach, small intestine and spleen) of rats irradiated with doses of 700 and 450 rads has been studied. Phase changes have been found in the taurine content of radiosensitive tissues in the course of radiation injury development

  18. Olaratumab for advanced soft tissue sarcoma.

    Science.gov (United States)

    Tobias, Alexander; O'brien, Michael P; Agulnik, Mark

    2017-07-01

    Olaratumab is a humanized IgG1 monoclonal antibody that blocks the platelet-derived growth factor receptor alpha (PDGFRα). Its antagonistic behavior inhibits the receptor's tyrosine kinase activity, thereby, turning off the downstream signaling cascades responsible for soft tissue sarcoma tumorigenesis. In October 2016, olaratumab received Food and Drug Administration (FDA) approval for its use in combination with doxorubicin for treatment of advanced soft tissue sarcoma. Areas covered: This drug profile takes a comprehensive look at the clinical studies leading to FDA approval of olaratumab as well as its safety and efficacy as a front-line treatment option for sarcoma patients. The literature search was primarily conducted using PubMed. Expert commentary: The combination of olaratumab plus doxorubicin has provided a new front-line therapeutic option for soft tissue sarcoma patients. An open-label phase Ib and randomized phase II trial in patients with advanced soft tissue sarcoma demonstrated that the addition of olaratumab to doxorubicin prolonged progression-free survival by 2.5 months and overall survival by 11.8 months when compared to doxorubicin alone. Of importance, this clinically meaningful increase in overall survival did not come at the expense of a significantly greater number of toxicities. A phase III confirmatory trial (ClinicalTrials.gov Identifier NCT02451943) will be completed in 2020.

  19. Spiral waves characterization: Implications for an automated cardiodynamic tissue characterization.

    Science.gov (United States)

    Alagoz, Celal; Cohen, Andrew R; Frisch, Daniel R; Tunç, Birkan; Phatharodom, Saran; Guez, Allon

    2018-07-01

    Spiral waves are phenomena observed in cardiac tissue especially during fibrillatory activities. Spiral waves are revealed through in-vivo and in-vitro studies using high density mapping that requires special experimental setup. Also, in-silico spiral wave analysis and classification is performed using membrane potentials from entire tissue. In this study, we report a characterization approach that identifies spiral wave behaviors using intracardiac electrogram (EGM) readings obtained with commonly used multipolar diagnostic catheters that perform localized but high-resolution readings. Specifically, the algorithm is designed to distinguish between stationary, meandering, and break-up rotors. The clustering and classification algorithms are tested on simulated data produced using a phenomenological 2D model of cardiac propagation. For EGM measurements, unipolar-bipolar EGM readings from various locations on tissue using two catheter types are modeled. The distance measure between spiral behaviors are assessed using normalized compression distance (NCD), an information theoretical distance. NCD is a universal metric in the sense it is solely based on compressibility of dataset and not requiring feature extraction. We also introduce normalized FFT distance (NFFTD) where compressibility is replaced with a FFT parameter. Overall, outstanding clustering performance was achieved across varying EGM reading configurations. We found that effectiveness in distinguishing was superior in case of NCD than NFFTD. We demonstrated that distinct spiral activity identification on a behaviorally heterogeneous tissue is also possible. This report demonstrates a theoretical validation of clustering and classification approaches that provide an automated mapping from EGM signals to assessment of spiral wave behaviors and hence offers a potential mapping and analysis framework for cardiac tissue wavefront propagation patterns. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Meat juice: An alternative matrix for assessing animal health by measuring acute phase proteins. Correlations of pig-MAP and haptoglobin concentrations in pig meat juice and plasma.

    Science.gov (United States)

    Piñeiro, M; Gymnich, S; Knura, S; Piñeiro, C; Petersen, B

    2009-10-01

    Quantification of acute phase proteins (APPs) in blood can be used for monitoring animal health and welfare on farms, and could be also of interest for the detection of diseased animals during the meat inspection process. However serum or plasma is not always available for end-point analysis at slaughter. Meat juice might provide an adequate, alternative matrix that can be easily obtained for post-mortem analysis at abattoirs. The concentrations of pig Major Acute phase Protein (pig-MAP) and haptoglobin, two of the main APPs in pigs, were determined in approximately 300 paired samples of plasma and meat juice from the diaphragm (pars costalis), obtained after freezing and thawing the muscle. APPs concentrations in meat juice were closely correlated to those in plasma (r=0.695 for haptoglobin, r=0.858 for pig-MAP, panimal health in pig production, with implications for food safety and meat quality.

  1. Simultaneous Localization and Mapping for Planetary Surface Mobility, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — ProtoInnovations, LLC and Carnegie Mellon University have formed a partnership to commercially develop localization and mapping technologies for planetary rovers....

  2. Mathematical models of soft tissue injury repair : towards understanding musculoskeletal disorders

    OpenAIRE

    Dunster, Joanne L.

    2012-01-01

    The process of soft tissue injury repair at the cellular lew I can be decomposed into three phases: acute inflammation including coagulation, proliferation and remodelling. While the later phases are well understood the early phase is less so. We produce a series of new mathematical models for the early phases coagulation and inflammation. The models produced are relevant not only to soft tissue injury repair but also to the many disease states in which coagulation and inflammation play a rol...

  3. Simplified absolute phase retrieval of dual-frequency fringe patterns in fringe projection profilometry

    Science.gov (United States)

    Lu, Jin; Mo, Rong; Sun, Huibin; Chang, Zhiyong; Zhao, Xiaxia

    2016-04-01

    In fringe projection profilometry, a simplified method is proposed to recover absolute phase maps of two-frequency fringe patterns by using a unique mapping rule. The mapping rule is designed from the rounded phase values to the fringe order of each pixel. Absolute phase can be recovered by the fringe order maps. Unlike the existing techniques, where the lowest frequency of dual- or multiple-frequency fringe patterns must be single, the presented method breaks the limitation and simplifies the procedure of phase unwrapping. Additionally, due to many issues including ambient light, shadow, sharp edges, step height boundaries and surface reflectivity variations, a novel framework of automatically identifying and removing invalid phase values is also proposed. Simulations and experiments have been carried out to validate the performances of the proposed method.

  4. Optimized phase gradient measurements and phase-amplitude interplay in optical coherence elastography

    Science.gov (United States)

    Zaitsev, Vladimir Y.; Matveyev, Alexander L.; Matveev, Lev A.; Gelikonov, Grigory V.; Sovetsky, Aleksandr A.; Vitkin, Alex

    2016-11-01

    In compressional optical coherence elastography, phase-variation gradients are used for estimating quasistatic strains created in tissue. Using reference and deformed optical coherence tomography (OCT) scans, one typically compares phases from pixels with the same coordinates in both scans. Usually, this limits the allowable strains to fairly small values advantages of the proposed optimized phase-variation methodology.

  5. Four-dimensional optoacoustic temperature mapping in laser-induced thermotherapy

    Science.gov (United States)

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

    2018-02-01

    Photoablative laser therapy is in common use for selective destruction of malignant masses, vascular and brain abnormalities. Tissue ablation and coagulation are irreversible processes occurring shortly after crossing a certain thermal exposure threshold. As a result, accurate mapping of the temperature field is essential for optimizing the outcome of these clinical interventions. Here we demonstrate four-dimensional optoacoustic temperature mapping of the entire photoablated region. Accuracy of the method is investigated in tissue-mimicking phantom experiments. Deviations of the volumetric optoacoustic temperature readings provided at 40ms intervals remained below 10% for temperature elevations above 3°C, as validated by simultaneous thermocouple measurements. The excellent spatio-temporal resolution of the new temperature monitoring approach aims at improving safety and efficacy of laser-based photothermal procedures.

  6. Imaging the spectral reflectance properties of bipolar radiofrequency-fused bowel tissue

    Science.gov (United States)

    Clancy, Neil T.; Arya, Shobhit; Stoyanov, Danail; Du, Xiaofei; Hanna, George B.; Elson, Daniel S.

    2015-07-01

    Delivery of radiofrequency (RF) electrical energy is used during surgery to heat and seal tissue, such as vessels, allowing resection without blood loss. Recent work has suggested that this approach may be extended to allow surgical attachment of larger tissue segments for applications such as bowel anastomosis. In a large series of porcine surgical procedures bipolar RF energy was used to resect and re-seal the small bowel in vivo with a commercial tissue fusion device (Ligasure; Covidien PLC, USA). The tissue was then imaged with a multispectral imaging laparoscope to obtain a spectral datacube comprising both fused and healthy tissue. Maps of blood volume, oxygen saturation and scattering power were derived from the measured reflectance spectra using an optimised light-tissue interaction model. A 60% increase in reflectance of visible light (460-700 nm) was observed after fusion, with the tissue taking on a white appearance. Despite this the distinctive shape of the haemoglobin absorption spectrum was still noticeable in the 460-600 nm wavelength range. Scattering power increased in the fused region in comparison to normal serosa, while blood volume and oxygen saturation decreased. Observed fusion-induced changes in the reflectance spectrum are consistent with the biophysical changes induced through tissue denaturation and increased collagen cross-linking. The multispectral imager allows mapping of the spatial extent of these changes and classification of the zone of damaged tissue. Further analysis of the spectral data in parallel with histopathological examination of excised specimens will allow correlation of the optical property changes with microscopic alterations in tissue structure.

  7. Defects in MAP1S-mediated autophagy turnover of fibronectin cause renal fibrosis.

    Science.gov (United States)

    Xu, Guibin; Yue, Fei; Huang, Hai; He, Yongzhong; Li, Xun; Zhao, Haibo; Su, Zhengming; Jiang, Xianhan; Li, Wenjiao; Zou, Jing; Chen, Qi; Liu, Leyuan

    2016-05-01

    Excessive deposition of extracellular matrix proteins in renal tissues causes renal fibrosis and renal function failure. Mammalian cells primarily use the autophagy-lysosome system to degrade misfolded/aggregated proteins and dysfunctional organelles. MAP1S is an autophagy activator and promotes the biogenesis and degradation of autophagosomes. Previously, we reported that MAP1S suppresses hepatocellular carcinogenesis in a mouse model and predicts a better prognosis in patients suffering from clear cell renal cell carcinomas. Furthermore, we have characterized that MAP1S enhances the turnover of fibronectin, and mice overexpressing LC3 but with MAP1S deleted accumulate fibronectin and develop liver fibrosis because of the synergistic impact of LC3-induced over-synthesis of fibronectin and MAP1S depletion-caused impairment of fibronectin degradation. Here we show that a suppression of MAP1S in renal cells caused an impairment of autophagy clearance of fibronectin and an activation of pyroptosis. Depletion of MAP1S in mice leads to an accumulation of fibrosis-related proteins and the development of renal fibrosis in aged mice. The levels of MAP1S were dramatically reduced and levels of fibronectin were greatly elevated in renal fibrotic tissues from patients diagnosed as renal atrophy and renal failure. Therefore, MAP1S deficiency may cause the accumulation of fibronectin and the development of renal fibrosis.

  8. Subsurface fracture mapping from geothermal wellbores. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hartenbaum, B.A.; Rawson, G.

    1983-08-01

    To advance the state-of-the-art in Hot Dry Rock technology, and evaluation is made of (1) the use of both electromagnetic and acoustic radar to map far-field fractures, (2) the use of more than twenty different conventional well logging tools to map borehole-fracture intercepts, (3) the use of magnetic dipole ranging to determine the relative positions of the injection well and the production well within the fractured zone, (4) the use of passive microseismic methods to determine the orientation and extent of hydraulic fractures, and (5) the application of signal processing techniques to fracture mapping including tomography, holography, synthetic aperture, image reconstruction, and the relative importance of phase and amplitude information. It is found that according to calculations, VHF backscatter radar has the potential for mapping fractures within a distance of 50 +- 20 meters from the wellbore. A new technique for improving fracture identification is presented. The range of acoustic radar is five to seven times greater than that of VHF radar when compared on the basis of equal resolution, i.e., equal wavelengths. Analyses of extant data indicate that when used synergistically the (1) caliper, (2) resistivity dipmeter, (3) televiewer, (4) television, (5) impression packer, and (6) acoustic transmission are useful for mapping borehole-fracture intercepts. A new model of hydraulic fracturing is presented which indicates that a hydraulic fracture is dynamically unstable; consequently, improvements in locating the crack tip may be possible. The importance of phase in signal processing is stressed and those techniques which employ phase data are emphasized for field use.

  9. NeuroMap: A spline-based interactive open-source software for spatiotemporal mapping of 2D and 3D MEA data

    Directory of Open Access Journals (Sweden)

    Oussama eAbdoun

    2011-01-01

    Full Text Available A major characteristic of neural networks is the complexity of their organization at various spatial scales, from microscopic local circuits to macroscopic brain-scale areas. Understanding how neural information is processed thus entails the ability to study them at multiple scales simultaneously. This is made possible using microelectrodes array (MEA technology. Indeed, high-density MEAs provide large-scale covering (several mm² of whole neural structures combined with microscopic resolution (about 50µm of unit activity. Yet, current options for spatiotemporal representation of MEA-collected data remain limited. Here we present NeuroMap, a new interactive Matlab-based software for spatiotemporal mapping of MEA data. NeuroMap uses thin plate spline interpolation, which provides several assets with respect to conventional mapping methods used currently. First, any MEA design can be considered, including 2D or 3D, regular or irregular, arrangements of electrodes. Second, spline interpolation allows the estimation of activity across the tissue with local extrema not necessarily at recording sites. Finally, this interpolation approach provides a straightforward analytical estimation of the spatial Laplacian for better current sources localization. In this software, coregistration of 2D MEA data on the anatomy of the neural tissue is made possible by fine matching of anatomical data with electrode positions using rigid deformation based correction of anatomical pictures. Overall, NeuroMap provides substantial material for detailed spatiotemporal analysis of MEA data. The package is distributed under GNU General Public License (GPL and available at http://sites.google.com/site/neuromapsoftware.

  10. NeuroMap: A Spline-Based Interactive Open-Source Software for Spatiotemporal Mapping of 2D and 3D MEA Data.

    Science.gov (United States)

    Abdoun, Oussama; Joucla, Sébastien; Mazzocco, Claire; Yvert, Blaise

    2011-01-01

    A major characteristic of neural networks is the complexity of their organization at various spatial scales, from microscopic local circuits to macroscopic brain-scale areas. Understanding how neural information is processed thus entails the ability to study them at multiple scales simultaneously. This is made possible using microelectrodes array (MEA) technology. Indeed, high-density MEAs provide large-scale coverage (several square millimeters) of whole neural structures combined with microscopic resolution (about 50 μm) of unit activity. Yet, current options for spatiotemporal representation of MEA-collected data remain limited. Here we present NeuroMap, a new interactive Matlab-based software for spatiotemporal mapping of MEA data. NeuroMap uses thin plate spline interpolation, which provides several assets with respect to conventional mapping methods used currently. First, any MEA design can be considered, including 2D or 3D, regular or irregular, arrangements of electrodes. Second, spline interpolation allows the estimation of activity across the tissue with local extrema not necessarily at recording sites. Finally, this interpolation approach provides a straightforward analytical estimation of the spatial Laplacian for better current sources localization. In this software, coregistration of 2D MEA data on the anatomy of the neural tissue is made possible by fine matching of anatomical data with electrode positions using rigid-deformation-based correction of anatomical pictures. Overall, NeuroMap provides substantial material for detailed spatiotemporal analysis of MEA data. The package is distributed under GNU General Public License and available at http://sites.google.com/site/neuromapsoftware.

  11. A phase IIb multicentre study comparing the efficacy of trabectedin to doxorubicin in patients with advanced or metastatic untreated soft tissue sarcoma: The TRUSTS trial

    NARCIS (Netherlands)

    Bui-Nguyen, B.; Butrynski, J.E.; Penel, N.; Blay, J.Y.; Isambert, N.; Milhem, M.; Kerst, J.M.; Reyners, A.K.; Litiere, S.; Marreaud, S.; Collin, F.; Graaf, W.T.A. van der

    2015-01-01

    PURPOSE: To evaluate whether trabectedin as first-line chemotherapy for advanced/metastatic soft tissue sarcoma prolongs progression-free survival (PFS), compared to doxorubicin and, in the phase IIb part here, to select the most appropriate trabectedin treatment schedule (3-hour or 24-hour

  12. Exploring the Nuclear Phase Diagram with Beam Energy Scans

    International Nuclear Information System (INIS)

    Horvat, Stephen

    2017-01-01

    The nuclear phase diagram is mapped using beam energy scans of relativistic heavy-ion collisions. This mapping is possible because different collision energies develop along different trajectories through the phase diagram. High energy collisions will evolve though a crossover phase transition according to lattice QCD, but lower collision energies may traverse a first order phase transition. There are hints for this first order phase transition and its critical endpoint, but further measurements and theoretical guidance is needed. In addition to mapping the phase transition, beam energy scans allow us to see if we can turn off the signatures of deconfinement. If an observable is a real signature for the formation of the deconfined state called quark-gluon plasma, then it should turn off at sufficiently low collision energies. In this summary talk I will show the current state of the field using beam energy scan results from RHIC and SPS, I will show where precise theoretical guidance is needed for understanding recent measurements, and I will motivate the need for more data and new measurements from FAIR, NICA, RHIC, and the SPS. (paper)

  13. Quantitative maps of protein phosphorylation sites across 14 different rat organs and tissues

    DEFF Research Database (Denmark)

    Lundby, Alicia; Secher, Anna; Lage, Kasper

    2012-01-01

    Deregulated cellular signalling is a common hallmark of disease, and delineating tissue phosphoproteomes is key to unravelling the underlying mechanisms. Here we present the broadest tissue catalogue of phosphoproteins to date, covering 31,480 phosphorylation sites on 7,280 proteins quantified ac...

  14. MeshSLAM: Robust Localization and Large-Scale Mapping in Barren Terrain, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Robots need to know their location to map of their surroundings but without global positioning data they need a map to identify their surroundings and estimate their...

  15. MeshSLAM: Robust Localization and Large-Scale Mapping in Barren Terrain, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Robots need to know their location to map of their surroundings but without global positioning data they need a map to identify their surroundings and estimate their...

  16. Developing web map application based on user centered design

    Directory of Open Access Journals (Sweden)

    Petr Voldan

    2012-03-01

    Full Text Available User centred design is an approach in process of development any kind of human product where the main idea is to create a product for the end user. This article presents User centred design method in developing web mapping services. This method can be split into four main phases – user research, creation of concepts, developing with usability research and lunch of product. The article describes each part of this phase with an aim to provide guidelines for developers and primarily with an aim to improve the usability of web mapping services.

  17. Fibroblast Growth Factors: Biology, Function, and Application for Tissue Regeneration

    Directory of Open Access Journals (Sweden)

    Ye-Rang Yun

    2010-01-01

    Full Text Available Fibroblast growth factors (FGFs that signal through FGF receptors (FGFRs regulate a broad spectrum of biological functions, including cellular proliferation, survival, migration, and differentiation. The FGF signal pathways are the RAS/MAP kinase pathway, PI3 kinase/AKT pathway, and PLCγ pathway, among which the RAS/MAP kinase pathway is known to be predominant. Several studies have recently implicated the in vitro biological functions of FGFs for tissue regeneration. However, to obtain optimal outcomes in vivo, it is important to enhance the half-life of FGFs and their biological stability. Future applications of FGFs are expected when the biological functions of FGFs are potentiated through the appropriate use of delivery systems and scaffolds. This review will introduce the biology and cellular functions of FGFs and deal with the biomaterials based delivery systems and their current applications for the regeneration of tissues, including skin, blood vessel, muscle, adipose, tendon/ligament, cartilage, bone, tooth, and nerve tissues.

  18. Cognitive Achievement and Motivation in Hands-on and Teacher-Centred Science Classes: Does an additional hands-on consolidation phase (concept mapping) optimise cognitive learning at work stations?

    Science.gov (United States)

    Gerstner, Sabine; Bogner, Franz X.

    2010-05-01

    Our study monitored the cognitive and motivational effects within different educational instruction schemes: On the one hand, teacher-centred versus hands-on instruction; on the other hand, hands-on instruction with and without a knowledge consolidation phase (concept mapping). All the instructions dealt with the same content. For all participants, the hands-on approach as well as the concept mapping adaptation were totally new. Our hands-on approach followed instruction based on "learning at work stations". A total of 397 high-achieving fifth graders participated in our study. We used a pre-test, post-test, retention test design both to detect students' short-term learning success and long-term learning success, and to document their decrease rates of newly acquired knowledge. Additionally, we monitored intrinsic motivation. Although the teacher-centred approach provided higher short-term learning success, hands-on instruction resulted in relatively lower decrease rates. However, after six weeks, all students reached similar levels of newly acquired knowledge. Nevertheless, concept mapping as a knowledge consolidation phase positively affected short-term increase in knowledge. Regularly placed in instruction, it might increase long-term retention rates. Scores of interest, perceived competence and perceived choice were very high in all the instructional schemes.

  19. Detecting phase synchronization by localized maps: Application to neural networks

    OpenAIRE

    Pereira, T.; Baptista, M. S.; Kurths, J.

    2007-01-01

    We present an approach which enables to state about the existence of phase synchronization in coupled chaotic oscillators without having to measure the phase. This is done by observing the oscillators at special times, and analyzing whether this set of points is localized. In particular, we show that this approach is fruitful to analyze the onset of phase synchronization in chaotic attractors whose phases are not well defined, as well as, in networks of non-identical spiking/bursting neurons ...

  20. Solid phase microextraction capillary gas chromatography combined with furnace atomization plasma emission spectrometry for speciation of mercury in fish tissues

    International Nuclear Information System (INIS)

    Grinberg, Patricia; Campos, Reinaldo C.; Mester, Zoltan; Sturgeon, Ralph E.

    2003-01-01

    The use of solid phase microextraction in conjunction with tandem gas chromatography-furnace atomization plasma emission spectrometry (SPME-GC-FAPES) was evaluated for the determination of methylmercury and inorganic mercury in fish tissue. Samples were digested with methanolic potassium hydroxide, derivatized with sodium tetraethylborate and extracted by SPME. After the SPME extraction, species were separated by GC and detected by FAPES. All experimental parameters were optimized for best separation and analytical response. A repeatability precision of typically 2% can be achieved with long-term (3 months) reproducibility precision of 4.3%. Certified Reference Materials DORM-2, DOLT-2 and TORT-2 from the National Research Council of Canada were analyzed to verify the accuracy of this technique. Detection limits of 1.5 ng g -1 for methylmercury and 0.7 ng g -1 for inorganic mercury in biological tissues were obtained

  1. Nonlinear dynamics of the relativistic standard map

    International Nuclear Information System (INIS)

    Nomura, Y.; Ichikawa, Y.H.; Horton, W.

    1991-04-01

    Heating and acceleration of charged particles by RF fields have been extensively investigated by the standard map. The question arises as to how the relativistic effects change the nonlinear dynamical behavior described by the classical standard map. The relativistic standard map is a two parameter (K, Β = ω/kc) family of dynamical systems reducing to the standard map when Β → 0. For Β ≠ 0 the relativistic mass increase suppresses the onset of stochasticity. It shown that the speed of light limits the rate of advance of the phase in the relativistic standard map and introduces KAM surfaces persisting in the high momentum region. An intricate structure of mixing in the higher order periodic orbits and chaotic orbits is analyzed using the symmetry properties of the relativistic standard map. The interchange of the stability of the periodic orbits in the relativistic standard map is also observed and is explained by the local linear stability of the orbits. 12 refs., 16 figs

  2. Matrix solid-phase dispersion coupled with homogeneous ionic liquid microextraction for the determination of sulfonamides in animal tissues using high-performance liquid chromatography.

    Science.gov (United States)

    Wang, Zhibing; He, Mengyu; Jiang, Chunzhu; Zhang, Fengqing; Du, Shanshan; Feng, Wennan; Zhang, Hanqi

    2015-12-01

    Matrix solid-phase dispersion coupled with homogeneous ionic liquid microextraction was developed and applied to the extraction of some sulfonamides, including sulfamerazine, sulfamethazine, sulfathiazole, sulfachloropyridazine, sulfadoxine, sulfisoxazole, and sulfaphenazole, in animal tissues. High-performance liquid chromatography was applied to the separation and determination of the target analytes. The solid sample was directly treated by matrix solid-phase dispersion and the eluate obtained was treated by homogeneous ionic liquid microextraction. The ionic liquid was used as the extraction solvent in this method, which may result in the improvement of the recoveries of the target analytes. To avoid using organic solvent and reduce environmental pollution, water was used as the elution solvent of matrix solid-phase dispersion. The effects of the experimental parameters on recoveries, including the type and volume of ionic liquid, type of dispersant, ratio of sample to dispersant, pH value of elution solvent, volume of elution solvent, amount of salt in eluate, amount of ion-pairing agent (NH4 PF6 ), and centrifuging time, were evaluated. When the present method was applied to the analysis of animal tissues, the recoveries of the analytes ranged from 85.4 to 118.0%, and the relative standard deviations were lower than 9.30%. The detection limits for the analytes were 4.3-13.4 μg/kg. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Practical obstacles and their mitigation strategies in compressional optical coherence elastography of biological tissues

    Directory of Open Access Journals (Sweden)

    Vladimir Y. Zaitsev

    2017-11-01

    Full Text Available In this paper, we point out some practical obstacles arising in realization of compressional optical coherence elastography (OCE that have not attracted sufficient attention previously. Specifically, we discuss (i complications in quantification of the Young modulus of tissues related to partial adhesion between the OCE probe and soft intervening reference layer sensor, (ii distorting influence of tissue surface curvature/corrugation on the subsurface strain distribution mapping, (iii ways of signal-to-noise ratio (SNR enhancement in OCE strain mapping when periodic averaging is not realized, and (iv potentially significant influence of tissue elastic nonlinearity on quantification of its stiffness. Potential practical approaches to mitigate the effects of these complications are also described.

  4. A Wearable Transcranial Doppler Ultrasound Phased Array System.

    Science.gov (United States)

    Pietrangelo, Sabino J; Lee, Hae-Seung; Sodini, Charles G

    2018-01-01

     Practical deficiencies related to conventional transcranial Doppler (TCD) sonography have restricted its use and applicability. This work seeks to mitigate several such constraints through the development of a wearable, electronically steered TCD velocimetry system, which enables noninvasive measurement of cerebral blood flow velocity (CBFV) for monitoring applications with limited operator interaction. A highly-compact, discrete prototype system was designed and experimentally validated through flow phantom and preliminary human subject testing. The prototype system incorporates a custom two-dimensional transducer array and multi-channel transceiver electronics, thereby facilitating acoustic beamformation via phased array operation. Electronic steering of acoustic energy enables algorithmic system controls to map Doppler power throughout the tissue volume of interest and localize regions of maximal flow. Multi-focal reception permits dynamic vessel position tracking and simultaneous flow velocimetry over the time-course of monitoring. Experimental flow phantom testing yielded high correlation with concurrent flowmeter recordings across the expected range of physiological flow velocities. Doppler power mapping has been validated in both flow phantom and preliminary human subject testing, resulting in average vessel location mapping times testing. A wearable prototype CBFV measurement system capable of autonomous vessel search and tracking has been presented. Although flow phantom and preliminary human validation show promise, further human subject testing is necessary to compare velocimetry data against existing commercial TCD systems. Additional human subject testing must also verify acceptable vessel search and tracking performance under a variety of subject populations and motion dynamics-such as head movement and ambulation.

  5. Numerical solution of non-linear dual-phase-lag bioheat transfer equation within skin tissues.

    Science.gov (United States)

    Kumar, Dinesh; Kumar, P; Rai, K N

    2017-11-01

    This paper deals with numerical modeling and simulation of heat transfer in skin tissues using non-linear dual-phase-lag (DPL) bioheat transfer model under periodic heat flux boundary condition. The blood perfusion is assumed temperature-dependent which results in non-linear DPL bioheat transfer model in order to predict more accurate results. A numerical method of line which is based on finite difference and Runge-Kutta (4,5) schemes, is used to solve the present non-linear problem. Under specific case, the exact solution has been obtained and compared with the present numerical scheme, and we found that those are in good agreement. A comparison based on model selection criterion (AIC) has been made among non-linear DPL models when the variation of blood perfusion rate with temperature is of constant, linear and exponential type with the experimental data and it has been found that non-linear DPL model with exponential variation of blood perfusion rate is closest to the experimental data. In addition, it is found that due to absence of phase-lag phenomena in Pennes bioheat transfer model, it achieves steady state more quickly and always predict higher temperature than thermal and DPL non-linear models. The effect of coefficient of blood perfusion rate, dimensionless heating frequency and Kirchoff number on dimensionless temperature distribution has also been analyzed. The whole analysis is presented in dimensionless form. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Dynamic map labeling.

    Science.gov (United States)

    Been, Ken; Daiches, Eli; Yap, Chee

    2006-01-01

    We address the problem of filtering, selecting and placing labels on a dynamic map, which is characterized by continuous zooming and panning capabilities. This consists of two interrelated issues. The first is to avoid label popping and other artifacts that cause confusion and interrupt navigation, and the second is to label at interactive speed. In most formulations the static map labeling problem is NP-hard, and a fast approximation might have O(nlogn) complexity. Even this is too slow during interaction, when the number of labels shown can be several orders of magnitude less than the number in the map. In this paper we introduce a set of desiderata for "consistent" dynamic map labeling, which has qualities desirable for navigation. We develop a new framework for dynamic labeling that achieves the desiderata and allows for fast interactive display by moving all of the selection and placement decisions into the preprocessing phase. This framework is general enough to accommodate a variety of selection and placement algorithms. It does not appear possible to achieve our desiderata using previous frameworks. Prior to this paper, there were no formal models of dynamic maps or of dynamic labels; our paper introduces both. We formulate a general optimization problem for dynamic map labeling and give a solution to a simple version of the problem. The simple version is based on label priorities and a versatile and intuitive class of dynamic label placements we call "invariant point placements". Despite these restrictions, our approach gives a useful and practical solution. Our implementation is incorporated into the G-Vis system which is a full-detail dynamic map of the continental USA. This demo is available through any browser.

  7. Development of multigene expression signature maps at the protein level from digitized immunohistochemistry slides.

    Directory of Open Access Journals (Sweden)

    Gregory J Metzger

    Full Text Available Molecular classification of diseases based on multigene expression signatures is increasingly used for diagnosis, prognosis, and prediction of response to therapy. Immunohistochemistry (IHC is an optimal method for validating expression signatures obtained using high-throughput genomics techniques since IHC allows a pathologist to examine gene expression at the protein level within the context of histologically interpretable tissue sections. Additionally, validated IHC assays may be readily implemented as clinical tests since IHC is performed on routinely processed clinical tissue samples. However, methods have not been available for automated n-gene expression profiling at the protein level using IHC data. We have developed methods to compute expression level maps (signature maps of multiple genes from IHC data digitized on a commercial whole slide imaging system. Areas of cancer for these expression level maps are defined by a pathologist on adjacent, co-registered H&E slides, allowing assessment of IHC statistics and heterogeneity within the diseased tissue. This novel way of representing multiple IHC assays as signature maps will allow the development of n-gene expression profiling databases in three dimensions throughout virtual whole organ reconstructions.

  8. Phase Control in Nonlinear Systems

    Science.gov (United States)

    Zambrano, Samuel; Seoane, Jesús M.; Mariño, Inés P.; Sanjuán, Miguel A. F.; Meucci, Riccardo

    The following sections are included: * Introduction * Phase Control of Chaos * Description of the model * Numerical exploration of phase control of chaos * Experimental evidence of phase control of chaos * Phase Control of Intermittency in Dynamical Systems * Crisis-induced intermittency and its control * Experimental setup and implementation of the phase control scheme * Phase control of the laser in the pre-crisis regime * Phase control of the intermittency after the crisis * Phase control of the intermittency in the quadratic map * Phase Control of Escapes in Open Dynamical Systems * Control of open dynamical systems * Model description * Numerical simulations and heuristic arguments * Experimental implementation in an electronic circuit * Conclusions and Discussions * Acknowledgments * References

  9. Performance of T2 Maps in the Detection of Prostate Cancer.

    Science.gov (United States)

    Chatterjee, Aritrick; Devaraj, Ajit; Mathew, Melvy; Szasz, Teodora; Antic, Tatjana; Karczmar, Gregory S; Oto, Aytekin

    2018-05-03

    This study compares the performance of T2 maps in the detection of prostate cancer (PCa) in comparison to T2-weighted (T2W) magnetic resonance images. The prospective study was institutional review board approved. Consenting patients (n = 45) with histologic confirmed PCa underwent preoperative 3-T magnetic resonance imaging with or without endorectal coil. Two radiologists, working independently, marked regions of interests (ROIs) on PCa lesions separately on T2W images and T2 maps. Each ROI was assigned a score of 1-5 based on the confidence in accurately detecting cancer, with 5 being the highest confidence. Subsequently, the histologically confirmed PCa lesions (n = 112) on whole-mount sections were matched with ROIs to calculate sensitivity, positive predictive value (PPV), and radiologist confidence score. Quantitative T2 values of PCa and benign tissue ROIs were measured. Sensitivity and confidence score for PCa detection were similar for T2W images (51%, 4.5 ± 0.8) and T2 maps (52%, 4.5 ± 0.6). However, PPV was significantly higher (P = .001) for T2 maps (88%) compared to T2W (72%) images. The use of endorectal coils nominally improved sensitivity (T2W: 55 vs 47%, T2 map: 54% vs 48%) compared to the use of no endorectal coils, but not the PPV and the confidence score. Quantitative T2 values for PCa (105 ± 28 milliseconds) were significantly (P = 9.3 × 10 -14 ) lower than benign peripheral zone tissue (211 ± 71 milliseconds), with moderate significant correlation with Gleason score (ρ = -0.284). Our study shows that review of T2 maps by radiologists has similar sensitivity but higher PPV compared to T2W images. Additional quantitative information obtained from T2 maps is helpful in differentiating cancer from normal prostate tissue and determining its aggressiveness. Copyright © 2018 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  10. Phase-locking and bistability in neuronal networks with synaptic depression

    Science.gov (United States)

    Akcay, Zeynep; Huang, Xinxian; Nadim, Farzan; Bose, Amitabha

    2018-02-01

    We consider a recurrent network of two oscillatory neurons that are coupled with inhibitory synapses. We use the phase response curves of the neurons and the properties of short-term synaptic depression to define Poincaré maps for the activity of the network. The fixed points of these maps correspond to phase-locked modes of the network. Using these maps, we analyze the conditions that allow short-term synaptic depression to lead to the existence of bistable phase-locked, periodic solutions. We show that bistability arises when either the phase response curve of the neuron or the short-term depression profile changes steeply enough. The results apply to any Type I oscillator and we illustrate our findings using the Quadratic Integrate-and-Fire and Morris-Lecar neuron models.

  11. Effect of dental adhesives on the exudative phase of the inflammatory process in subcutaneous tissue of rats

    Directory of Open Access Journals (Sweden)

    Nagem-Filho Halim

    2003-01-01

    Full Text Available The vascular changes in the subcutaneous connective tissue of rats induced by dentin bonding systems (one step was studied and compared to those induced by saline solution (negative control and Furacin (positive control, during the exudative phase of the inflammatory process. Twenty mg/kg of Evan's blue were injected intravenously in the vein of the rats' penises; 0.1 ml of each substance tested was inoculated in the subcutaneous tissue. After a 3 hour period the animals were sacrificed and their skins were excised and punched out with a standard steel 2.5 cm in diameter. The specimens were immediately immersed in 8 ml of formamide and taken to a double boiler for 72 hours at 37ºC, to remove the dye. The liquid containing the overflowed dye was filtered, analyzed in the spectrophotometer (620 nm and classified according to the criteria established by Nagem-Filho, Pereira (1976. After statistical analysis, the irritative potential of the substances was ranked as follows: Furacin (severe > Single Bond and Bond 1 (moderate - no significant differences between the dentin bonding systems tested > saline solution (not significant as regards the irritation degree.

  12. Identification and target prediction of miRNAs specifically expressed in rat neural tissue

    Directory of Open Access Journals (Sweden)

    Tu Kang

    2009-05-01

    Full Text Available Abstract Background MicroRNAs (miRNAs are a large group of RNAs that play important roles in regulating gene expression and protein translation. Several studies have indicated that some miRNAs are specifically expressed in human, mouse and zebrafish tissues. For example, miR-1 and miR-133 are specifically expressed in muscles. Tissue-specific miRNAs may have particular functions. Although previous studies have reported the presence of human, mouse and zebrafish tissue-specific miRNAs, there have been no detailed reports of rat tissue-specific miRNAs. In this study, Home-made rat miRNA microarrays which established in our previous study were used to investigate rat neural tissue-specific miRNAs, and mapped their target genes in rat tissues. This study will provide information for the functional analysis of these miRNAs. Results In order to obtain as complete a picture of specific miRNA expression in rat neural tissues as possible, customized miRNA microarrays with 152 selected miRNAs from miRBase were used to detect miRNA expression in 14 rat tissues. After a general clustering analysis, 14 rat tissues could be clearly classified into neural and non-neural tissues based on the obtained expression profiles with p values Conclusion Our work provides a global view of rat neural tissue-specific miRNA profiles and a target map of miRNAs, which is expected to contribute to future investigations of miRNA regulatory mechanisms in neural systems.

  13. Influence of contact force on voltage mapping: A combined magnetic resonance imaging and electroanatomic mapping study in patients with tetralogy of Fallot.

    Science.gov (United States)

    Teijeira-Fernandez, Elvis; Cochet, Hubert; Bourier, Felix; Takigawa, Masateru; Cheniti, Ghassen; Thompson, Nathaniel; Frontera, Antonio; Camaioni, Claudia; Massouille, Gregoire; Jalal, Zakaria; Derval, Nicolas; Iriart, Xavier; Denis, Arnaud; Hocini, Meleze; Haissaguerre, Michel; Jais, Pierre; Thambo, Jean-Benoit; Sacher, Frederic

    2018-03-20

    Voltage criteria for ventricular mapping have been obtained from small series of patients and prioritizing high specificity. The purpose of this study was to analyse the potential influence of contact force (CF) on voltage mapping and to define voltage cutoff values for right ventricular (RV) scar using the tetralogy of Fallot as a model of transmural RV scar and magnetic resonance imaging (MRI) as reference. Fourteen patients (age 32.6 ± 14.3 years; 5 female) with repaired tetralogy of Fallot underwent high-resolution cardiac MRI (1.25 × 1.25 × 2.5 mm). Scar, defined as pixels with intensity >50% maximum, was mapped over the RV geometry and merged within the CARTO system to RV endocardial voltage maps acquired using a 3.5-mm ablation catheter with CF technology (SmartTouch, Biosense Webster). In total, 2446 points were analyzed, 915 within scars and 1531 in healthy tissue according to MRI. CF correlated to unipolar (ρ = 0.186; P voltage in healthy tissue (ρ = 0.245; P voltage cutoffs of 5.19 mV for unipolar voltage and 1.76 mV for bipolar voltage, yielding sensitivity/specificity of 0.89/0.85 and 0.9/0.9, respectively. CF is an important factor to be taken into account for voltage mapping. If good CF is applied, unipolar and bipolar voltage cutoffs of 5.19 mV and 1.76 mV are optimal for identifying RV scar on endocardial mapping with the SmartTouch catheter. Data on the diagnostic accuracy of different voltage cutoff values are provided. Copyright © 2018 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  14. On-off intermittency and coherent bursting in stochastically-driven coupled maps

    International Nuclear Information System (INIS)

    Metta, Sabino; Provenzale, Antonello; Spiegel, Edward A.

    2010-01-01

    On-off intermittency is a phase space mechanism for bursting in dynamical systems. Here we recall how the simple example of a logistic map with a time-dependent control parameter, considered as a dynamical variable of the system, gives rise to bursting or on-off behavior. We show that, for a given realization of the driver, a stochastically driven logistic map in the on-off intermittent regime always converges to the same temporal dynamics, independently of initial conditions. In that sense, the map is not chaotic. We then explore the behavior of two coupled on-off logistic maps, each driven by a separate random process, and show that, for a wide range of coupling strengths, bursting becomes at least partially coherent. The bursting coherence has a smooth dependence on the coupling parameter and no sharp transition from coherence to incoherence is detected. In the system of two coupled on-off maps studied here, coherent bursting is rooted in the behavior during off phases when the mapped coordinates take on extremely small values.

  15. Towards the map of quantum gravity

    Science.gov (United States)

    Mielczarek, Jakub; Trześniewski, Tomasz

    2018-06-01

    In this paper we point out some possible links between different approaches to quantum gravity and theories of the Planck scale physics. In particular, connections between loop quantum gravity, causal dynamical triangulations, Hořava-Lifshitz gravity, asymptotic safety scenario, Quantum Graphity, deformations of relativistic symmetries and nonlinear phase space models are discussed. The main focus is on quantum deformations of the Hypersurface Deformations Algebra and Poincaré algebra, nonlinear structure of phase space, the running dimension of spacetime and nontrivial phase diagram of quantum gravity. We present an attempt to arrange the observed relations in the form of a graph, highlighting different aspects of quantum gravity. The analysis is performed in the spirit of a mind map, which represents the architectural approach to the studied theory, being a natural way to describe the properties of a complex system. We hope that the constructed graphs (maps) will turn out to be helpful in uncovering the global picture of quantum gravity as a particular complex system and serve as a useful guide for the researchers.

  16. Probability mapping of scarred myocardium using texture and intensity features in CMR images

    Science.gov (United States)

    2013-01-01

    Background The myocardium exhibits heterogeneous nature due to scarring after Myocardial Infarction (MI). In Cardiac Magnetic Resonance (CMR) imaging, Late Gadolinium (LG) contrast agent enhances the intensity of scarred area in the myocardium. Methods In this paper, we propose a probability mapping technique using Texture and Intensity features to describe heterogeneous nature of the scarred myocardium in Cardiac Magnetic Resonance (CMR) images after Myocardial Infarction (MI). Scarred tissue and non-scarred tissue are represented with high and low probabilities, respectively. Intermediate values possibly indicate areas where the scarred and healthy tissues are interwoven. The probability map of scarred myocardium is calculated by using a probability function based on Bayes rule. Any set of features can be used in the probability function. Results In the present study, we demonstrate the use of two different types of features. One is based on the mean intensity of pixel and the other on underlying texture information of the scarred and non-scarred myocardium. Examples of probability maps computed using the mean intensity of pixel and the underlying texture information are presented. We hypothesize that the probability mapping of myocardium offers alternate visualization, possibly showing the details with physiological significance difficult to detect visually in the original CMR image. Conclusion The probability mapping obtained from the two features provides a way to define different cardiac segments which offer a way to identify areas in the myocardium of diagnostic importance (like core and border areas in scarred myocardium). PMID:24053280

  17. Fracture mapping at the Spent Fuel Test-Climax

    International Nuclear Information System (INIS)

    Wilder, D.G.; Yow, J.L. Jr.

    1981-05-01

    Mapping of geologic discontinuities has been done in several phases at the Spent Fuel Test-Climax (SFT-C) in the granitic Climax stock at the Nevada Test Site. Mapping was carried out in the tail drift, access drift, canister drift, heater drifts, instrumentation alcove, and receiving room. The fractures mapped as intersecting a horizontal datum in the canister and heater drifts are shown on one figure. Fracture sketch maps have been compiled as additional figures. Geologic mapping efforts were scheduled around and significantly impacted by the excavation and construction schedules. Several people were involved in the mapping, and over 2500 geologic discontinuities were mapped, including joints, shears, and faults. Some variance between individuals' mapping efforts was noticed, and the effects of various magnetic influences upon a compass were examined. The examination of compass errors improved the credibility of the data. The compass analysis work is explained in Appendix A. Analysis of the fracture data will be presented in a future report

  18. An electrical impedance tomography (EIT) multi-electrode needle-probe device for local assessment of heterogeneous tissue impeditivity.

    Science.gov (United States)

    Meroni, Davide; Maglioli, Camilla Carpano; Bovio, Dario; Greco, Francesco G; Aliverti, Andrea

    2017-07-01

    Electrical Impedance Tomography (EIT) is an image reconstruction technique applied in medicine for the electrical imaging of living tissues. In literature there is the evidence that a large resistivity variation related to the differences of the human tissues exists. As a result of this interest for the electrical characterization of the biological samples, recently the attention is also focused on the identification and characterization of the human tissue, by studying the homogeneity of its structure. An 8 electrodes needle-probe device has been developed with the intent of identifying the structural inhomogeneities under the surface layers. Ex-vivo impeditivity measurements, by placing the needle-probe in 5 different patterns of fat and lean porcine tissue, were performed, and impeditivity maps were obtained by EIDORS open source software for image reconstruction in electrical impedance. The values composing the maps have been analyzed, pointing out a good tissue discrimination, and the conformity with the real images. We conclude that this device is able to perform impeditivity maps matching to reality for position and orientation. In all the five patterns presented is possible to identify and replicate correctly the heterogeneous tissue under test. This new procedure can be helpful to the medical staff to completely characterize the biological sample, in different unclear situations.

  19. Fibrovascular tissue in bilateral juxtafoveal telangiectasis.

    Science.gov (United States)

    Park, D; Schatz, H; McDonald, H R; Johnson, R N

    1996-09-01

    To study the natural history and retinal findings associated with the intraretinal and subretinal fibrovascular tissues that develop in the late phases of bilateral juxtafoveal telangiectasis. The records of 10 patients (11 eyes) with bilateral juxtafoveal telangiectasis who developed these fibrovascular tissues were examined. Throughout the follow-up period (average 44 months), only 2 eyes (18%) lost 2 or more lines of vision; the final visual acuities were similar for the eyes both with and without fibrovascular tissues. Sixty-four percent of fibrovascular tissues showed little to no growth. Eyes with fibrovascular tissue commonly had retinal pigment epithelial hyperplasia (72%), draining retinal venules (82%), and retinal vascular distortion (64%). Fibrovascular tissues of bilateral juxtafoveal telangiectasis have little proliferative potential and minimal effects on visual acuity. Nevertheless, these fibrovascular tissues do remodel over time, leading to retinal vascular distortion. Given these benign findings, the role of laser photocoagulation treatment of these tissues is questionable.

  20. Tracking cognitive phases in analogical reasoning with event-related potentials.

    Science.gov (United States)

    Maguire, Mandy J; McClelland, M Michelle; Donovan, Colin M; Tillman, Gail D; Krawczyk, Daniel C

    2012-03-01

    Analogical reasoning consists of multiple phases. Four-term analogies (A:B::C:D) have an encoding period in which the A:B pair is evaluated prior to a mapping phase. The electrophysiological timing associated with analogical reasoning has remained unclear. We used event-related potentials to identify neural timing related to analogical reasoning relative to perceptual and semantic control conditions. Spatiotemporal principal-components analyses revealed differences primarily in left frontal electrodes during encoding and mapping phases of analogies relative to the other conditions. The timing of the activity differed depending upon the phase of the problem. During the encoding of A:B terms, analogies elicited a positive deflection compared to the control conditions between 400 and 1,200 ms, but for the mapping phase analogical processing elicited a negative deflection that occurred earlier and for a shorter time period, between 350 and 625 ms. These results provide neural and behavioral evidence that 4-term analogy problems involve a highly active evaluation phase of the A:B pair. 2012 APA, all rights reserved

  1. Direct tissue oxygen monitoring by in vivo photoacoustic lifetime imaging (PALI)

    Science.gov (United States)

    Shao, Qi; Morgounova, Ekaterina; Ashkenazi, Shai

    2014-03-01

    Tissue oxygen plays a critical role in maintaining tissue viability and in various diseases, including response to therapy. Images of oxygen distribution provide the history of tissue hypoxia and evidence of oxygen availability in the circulatory system. Currently available methods of direct measuring or imaging tissue oxygen all have significant limitations. Previously, we have reported a non-invasive in vivo imaging modality based on photoacoustic lifetime. The technique maps the excited triplet state of oxygen-sensitive dye, thus reflects the spatial and temporal distribution of tissue oxygen. We have applied PALI on tumor hypoxia in small animals, and the hypoxic region imaged by PALI is consistent with the site of the tumor imaged by ultrasound. Here, we present two studies of applying PALI to monitor changes of tissue oxygen by modulations. The first study involves an acute ischemia model using a thin thread tied around the hind limb of a normal mouse to reduce the blood flow. PALI images were acquired before, during, and after the restriction. The drop of muscle pO2 and recovery from hypoxia due to reperfusion were observed by PALI tracking the same region. The second study modulates tissue oxygen by controlling the percentage of oxygen the mouse inhales. We demonstrate that PALI is able to reflect the change of oxygen level with respect to both hyperbaric and hypobaric conditions. We expect this technique to be very attractive for a range of clinical applications in which tissue oxygen mapping would improve therapy decision making and treatment planning.

  2. Phase Aberration and Attenuation Effects on Acoustic Radiation Force-Based Shear Wave Generation.

    Science.gov (United States)

    Carrascal, Carolina Amador; Aristizabal, Sara; Greenleaf, James F; Urban, Matthew W

    2016-02-01

    Elasticity is measured by shear wave elasticity imaging (SWEI) methods using acoustic radiation force to create the shear waves. Phase aberration and tissue attenuation can hamper the generation of shear waves for in vivo applications. In this study, the effects of phase aberration and attenuation in ultrasound focusing for creating shear waves were explored. This includes the effects of phase shifts and amplitude attenuation on shear wave characteristics such as shear wave amplitude, shear wave speed, shear wave center frequency, and bandwidth. Two samples of swine belly tissue were used to create phase aberration and attenuation experimentally. To explore the phase aberration and attenuation effects individually, tissue experiments were complemented with ultrasound beam simulations using fast object-oriented C++ ultrasound simulator (FOCUS) and shear wave simulations using finite-element-model (FEM) analysis. The ultrasound frequency used to generate shear waves was varied from 3.0 to 4.5 MHz. Results: The measured acoustic pressure and resulting shear wave amplitude decreased approximately 40%-90% with the introduction of the tissue samples. Acoustic intensity and shear wave displacement were correlated for both tissue samples, and the resulting Pearson's correlation coefficients were 0.99 and 0.97. Analysis of shear wave generation with tissue samples (phase aberration and attenuation case), measured phase screen, (only phase aberration case), and FOCUS/FEM model (only attenuation case) showed that tissue attenuation affected the shear wave generation more than tissue aberration. Decreasing the ultrasound frequency helped maintain a focused beam for creation of shear waves in the presence of both phase aberration and attenuation.

  3. A biphasic model for bleeding in soft tissue

    Science.gov (United States)

    Chang, Yi-Jui; Chong, Kwitae; Eldredge, Jeff D.; Teran, Joseph; Benharash, Peyman; Dutson, Erik

    2017-11-01

    The modeling of blood passing through soft tissues in the body is important for medical applications. The current study aims to capture the effect of tissue swelling and the transport of blood under bleeding or hemorrhaging conditions. The soft tissue is considered as a non-static poro-hyperelastic material with liquid-filled voids. A biphasic formulation effectively, a generalization of Darcy's law-is utilized, treating the phases as occupying fractions of the same volume. The interaction between phases is captured through a Stokes-like friction force on their relative velocities and a pressure that penalizes deviations from volume fractions summing to unity. The soft tissue is modeled as a hyperelastic material with a typical J-shaped stress-strain curve, while blood is considered as a Newtonian fluid. The method of Smoothed Particle Hydrodynamics is used to discretize the conservation equations based on the ease of treating free surfaces in the liquid. Simulations of swelling under acute hemorrhage and of draining under gravity and compression will be demonstrated. Ongoing progress in modeling of organ tissues under injuries and surgical conditions will be discussed.

  4. Blind source separation of ex-vivo aorta tissue multispectral images.

    Science.gov (United States)

    Galeano, July; Perez, Sandra; Montoya, Yonatan; Botina, Deivid; Garzón, Johnson

    2015-05-01

    Blind Source Separation methods (BSS) aim for the decomposition of a given signal in its main components or source signals. Those techniques have been widely used in the literature for the analysis of biomedical images, in order to extract the main components of an organ or tissue under study. The analysis of skin images for the extraction of melanin and hemoglobin is an example of the use of BSS. This paper presents a proof of concept of the use of source separation of ex-vivo aorta tissue multispectral Images. The images are acquired with an interference filter-based imaging system. The images are processed by means of two algorithms: Independent Components analysis and Non-negative Matrix Factorization. In both cases, it is possible to obtain maps that quantify the concentration of the main chromophores present in aortic tissue. Also, the algorithms allow for spectral absorbance of the main tissue components. Those spectral signatures were compared against the theoretical ones by using correlation coefficients. Those coefficients report values close to 0.9, which is a good estimator of the method's performance. Also, correlation coefficients lead to the identification of the concentration maps according to the evaluated chromophore. The results suggest that Multi/hyper-spectral systems together with image processing techniques is a potential tool for the analysis of cardiovascular tissue.

  5. Connective tissue regeneration in skeletal muscle after eccentric contraction-induced injury

    DEFF Research Database (Denmark)

    Mackey, Abigail Louise; Kjaer, Michael

    2017-01-01

    Human skeletal muscle has the potential to regenerate completely after injury induced under controlled experimental conditions. The events inside the myofibres as they undergo necrosis, followed closely by satellite cell mediated myogenesis, have been mapped in detail. Much less is known about...... the adaptation throughout this process of both the connective tissue structures surrounding the myofibres, and the fibroblasts, the cells responsible for synthesising this connective tissue. However, the few studies investigating muscle connective tissue remodelling demonstrate a strong response that appears...

  6. Irradiation-induced hypoxia in bones and soft tissues: an experimental study

    International Nuclear Information System (INIS)

    Aitasalo, K.; Aro, H.

    1986-01-01

    Bone marrow and subcutaneous tissue pO 2 and pCO 2 were measured by means of implanted tissue tonometers in irradiated and nonirradiated rabbit hind limbs. The x-ray dose was 500, 1000, 1500, 2000, and 3000 rads. Tissue gas tensions were measured 1 day and 5 and 11 weeks after radiation. The pCO 2 changes in both tissues were slight but not statistically significant. The subcutaneous tissue pO 2 decreased during the acute phase of irradiation injury, and the effect of irradiation was dose-dependent. Later on, irradiation had no significant effects on the subcutaneous pO 2 , although light microscopy of the affected tissues showed fibrosis and blood vessel changes. The response of the subcutaneous pO 2 to systemic hyperoxia also increased in the chronic phase of irradiation injury as a sign of improved microcirculation. The bone marrow showed a high radiosensitivity. Irradiation caused a rapid dose-dependent decrease of the marrow pO 2 , and the marrow pO 2 decreased with time during the chronic phase of irradiation injury. The marrow pO 2 responded slowly and marginally to an increment of arterial pO 2 during breathing 100% oxygen as further evidence of impaired vascular pattern. The results showed that irradiation causes only a transient impairment of tissue perfusion in the skin. However, irradiation-damaged marrow was characterized by progressive tissue hypoxia

  7. Sensitivity of microwave ablation models to tissue biophysical properties: A first step toward probabilistic modeling and treatment planning.

    Science.gov (United States)

    Sebek, Jan; Albin, Nathan; Bortel, Radoslav; Natarajan, Bala; Prakash, Punit

    2016-05-01

    (permittivity) had 22.26 times higher influence on the deviation of ablation edge shape from a sphere than one of the less important parameters (latent heat of liver tissue vaporization). Dielectric parameters, blood perfusion rate, and the temperature interval across which the tissue changes phase were found to have the most significant impact on MWA model outputs. The latent heat of tissue water vaporization and the volumetric heat capacity of the vaporized tissue were recognized as the least influential parameters. Uncertainties in model outputs identified in this study can be incorporated to provide probabilistic maps of expected ablation outcome for patient-specific treatment planning.

  8. Susceptibility-Weighted Imaging and Quantitative Susceptibility Mapping in the Brain

    Science.gov (United States)

    Liu, Chunlei; Li, Wei; Tong, Karen A.; Yeom, Kristen W.; Kuzminski, Samuel

    2015-01-01

    Susceptibility-weighted imaging (SWI) is a magnetic resonance imaging (MRI) technique that enhances image contrast by using the susceptibility differences between tissues. It is created by combining both magnitude and phase in the gradient echo data. SWI is sensitive to both paramagnetic and diamagnetic substances which generate different phase shift in MRI data. SWI images can be displayed as a minimum intensity projection that provides high resolution delineation of the cerebral venous architecture, a feature that is not available in other MRI techniques. As such, SWI has been widely applied to diagnose various venous abnormalities. SWI is especially sensitive to deoxygenated blood and intracranial mineral deposition and, for that reason, has been applied to image various pathologies including intracranial hemorrhage, traumatic brain injury, stroke, neoplasm, and multiple sclerosis. SWI, however, does not provide quantitative measures of magnetic susceptibility. This limitation is currently being addressed with the development of quantitative susceptibility mapping (QSM) and susceptibility tensor imaging (STI). While QSM treats susceptibility as isotropic, STI treats susceptibility as generally anisotropic characterized by a tensor quantity. This article reviews the basic principles of SWI, its clinical and research applications, the mechanisms governing brain susceptibility properties, and its practical implementation, with a focus on brain imaging. PMID:25270052

  9. Susceptibility-weighted imaging and quantitative susceptibility mapping in the brain.

    Science.gov (United States)

    Liu, Chunlei; Li, Wei; Tong, Karen A; Yeom, Kristen W; Kuzminski, Samuel

    2015-07-01

    Susceptibility-weighted imaging (SWI) is a magnetic resonance imaging (MRI) technique that enhances image contrast by using the susceptibility differences between tissues. It is created by combining both magnitude and phase in the gradient echo data. SWI is sensitive to both paramagnetic and diamagnetic substances which generate different phase shift in MRI data. SWI images can be displayed as a minimum intensity projection that provides high resolution delineation of the cerebral venous architecture, a feature that is not available in other MRI techniques. As such, SWI has been widely applied to diagnose various venous abnormalities. SWI is especially sensitive to deoxygenated blood and intracranial mineral deposition and, for that reason, has been applied to image various pathologies including intracranial hemorrhage, traumatic brain injury, stroke, neoplasm, and multiple sclerosis. SWI, however, does not provide quantitative measures of magnetic susceptibility. This limitation is currently being addressed with the development of quantitative susceptibility mapping (QSM) and susceptibility tensor imaging (STI). While QSM treats susceptibility as isotropic, STI treats susceptibility as generally anisotropic characterized by a tensor quantity. This article reviews the basic principles of SWI, its clinical and research applications, the mechanisms governing brain susceptibility properties, and its practical implementation, with a focus on brain imaging. © 2014 Wiley Periodicals, Inc.

  10. Synthetic aperture tissue and flow ultrasound imaging

    DEFF Research Database (Denmark)

    Nikolov, Svetoslav

    imaging applied to medical ultrasound. It is divided into two major parts: tissue and blood flow imaging. Tissue imaging using synthetic aperture algorithms has been investigated for about two decades, but has not been implemented in medical scanners yet. Among the other reasons, the conventional scanning...... and beamformation methods are adequate for the imaging modalities in clinical use - the B-mode imaging of tissue structures, and the color mapping of blood flow. The acquisition time, however, is too long, and these methods fail to perform real-time three-dimensional scans. The synthetic transmit aperture......, on the other hand, can create a Bmode image with as little as 2 emissions, thus significantly speeding-up the scan procedure. The first part of the dissertation describes the synthetic aperture tissue imaging. It starts with an overview of the efforts previously made by other research groups. A classification...

  11. Topological visual mapping in robotics.

    Science.gov (United States)

    Romero, Anna; Cazorla, Miguel

    2012-08-01

    A key problem in robotics is the construction of a map from its environment. This map could be used in different tasks, like localization, recognition, obstacle avoidance, etc. Besides, the simultaneous location and mapping (SLAM) problem has had a lot of interest in the robotics community. This paper presents a new method for visual mapping, using topological instead of metric information. For that purpose, we propose prior image segmentation into regions in order to group the extracted invariant features in a graph so that each graph defines a single region of the image. Although others methods have been proposed for visual SLAM, our method is complete, in the sense that it makes all the process: it presents a new method for image matching; it defines a way to build the topological map; and it also defines a matching criterion for loop-closing. The matching process will take into account visual features and their structure using the graph transformation matching (GTM) algorithm, which allows us to process the matching and to remove out the outliers. Then, using this image comparison method, we propose an algorithm for constructing topological maps. During the experimentation phase, we will test the robustness of the method and its ability constructing topological maps. We have also introduced new hysteresis behavior in order to solve some problems found building the graph.

  12. Optical multiple-image encryption based on multiplane phase retrieval and interference

    International Nuclear Information System (INIS)

    Chen, Wen; Chen, Xudong

    2011-01-01

    In this paper, we propose a new method for optical multiple-image encryption based on multiplane phase retrieval and interference. An optical encoding system is developed in the Fresnel domain. A phase-only map is iteratively extracted based on a multiplane phase retrieval algorithm, and multiple plaintexts are simultaneously encrypted. Subsequently, the extracted phase-only map is further encrypted into two phase-only masks based on a non-iterative interference algorithm. During image decryption, the advantages and security of the proposed optical cryptosystem are analyzed. Numerical results are presented to demonstrate the validity of the proposed optical multiple-image encryption method

  13. Computational Phase Imaging for Biomedical Applications

    Science.gov (United States)

    Nguyen, Tan Huu

    laser comes at the expense of speckles, which degrades image quality. Therefore, solutions purely based on physical modeling and computations to remove these artifacts, using white-light illumination, are highly desirable. Here, using physical optics, we develop a theoretical model that accurately explains the effects of partial coherence on image information and phase information. The model is further combined with numerical processing to suppress the artifacts, and recover the correct phase information. The third topic is devoted to applying QPI to clinical applications. Traditionally, stained tissues are used in prostate cancer diagnosis instead. The reason is that tissue samples used in diagnosis are nearly transparent under bright field inspection if unstained. Contrast-enhanced microscopy techniques, e.g., phase contrast microscopy (PC) and differential interference contrast microscopy (DIC), can render visibility of the untagged samples with high throughput. However, since these methods are intensity-based, the contrast of acquired images varies significantly from one imaging facility to another, preventing them from being used in diagnosis. Inheriting the merits of PC, SLIM produces phase maps, which measure the refractive index of label-free samples. However, the maps measured by SLIM are not affected by variation in imaging conditions, e.g., illumination, magnification, etc., allowing consistent imaging results when using SLIM across different clinical institutions. Here, we combine SLIM images with machine learning for automatic diagnosis results for prostate cancer. We focus on two diagnosis problems of automatic Gleason grading and cancer vs. non-cancer diagnosis. Finally, we introduce a new imaging modality, named Gradient Light Interference Microscopy (GLIM), which is able to image through optically thick samples using low spatial coherence illumination. The key benefit of GLIM comes from a large numerical aperture of the condenser, which is 0.55 NA

  14. Nonlinear dynamics of the relativistic standard map

    International Nuclear Information System (INIS)

    Nomura, Y.; Ichikawa, Y.H.; Horton, W.

    1991-01-01

    Heating and acceleration of charged particles by RF fields have been extensively investigated by the standard map (ST). Thus, it is natural to pose the question asking how the relativistic effects change the nonlinear dynamical behavior described by the classical ST map. The authors show that the speed of light limits the rate of advance of the phase in the relativistic standard map (RST) and introduces KAM surfaces persisting in the high momentum region. The RST map is a two parameter (k, β = ω/kc) family of dynamics reducing to the ST map when β → 0. For β ≠ 0 the relativity suppresses the onset of stochasticity. Chernikov et al. has also reported this effect. They have carried out extensive studies of nonlinear dynamics of the RST map and found very intricate structure of mixing of the higher order periodic orbits and chaotic orbits. They have shown that no matter how its gets chaotic the symmetry properties of the RST map determines its nonlinear dynamical behavior. 1 ref

  15. Quantitative investigation of the edge enhancement in in-line phase contrast projections and tomosynthesis provided by distributing microbubbles on the interface between two tissues: a phantom study

    Science.gov (United States)

    Wu, Di; Donovan Wong, Molly; Li, Yuhua; Fajardo, Laurie; Zheng, Bin; Wu, Xizeng; Liu, Hong

    2017-12-01

    The objective of this study was to quantitatively investigate the ability to distribute microbubbles along the interface between two tissues, in an effort to improve the edge and/or boundary features in phase contrast imaging. The experiments were conducted by employing a custom designed tissue simulating phantom, which also simulated a clinical condition where the ligand-targeted microbubbles are self-aggregated on the endothelium of blood vessels surrounding malignant cells. Four different concentrations of microbubble suspensions were injected into the phantom: 0%, 0.1%, 0.2%, and 0.4%. A time delay of 5 min was implemented before image acquisition to allow the microbubbles to become distributed at the interface between the acrylic and the cavity simulating a blood vessel segment. For comparison purposes, images were acquired using three system configurations for both projection and tomosynthesis imaging with a fixed radiation dose delivery: conventional low-energy contact mode, low-energy in-line phase contrast and high-energy in-line phase contrast. The resultant images illustrate the edge feature enhancements in the in-line phase contrast imaging mode when the microbubble concentration is extremely low. The quantitative edge-enhancement-to-noise ratio calculations not only agree with the direct image observations, but also indicate that the edge feature enhancement can be improved by increasing the microbubble concentration. In addition, high-energy in-line phase contrast imaging provided better performance in detecting low-concentration microbubble distributions.

  16. Strain mapping of LED devices by dark-field inline electron holography: Comparison between deterministic and iterative phase retrieval approaches

    Energy Technology Data Exchange (ETDEWEB)

    Song, Kyung; Shin, Ga-Young; Kim, Jong Kyu [Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), San 31 Hyoja-dong, Nam-gu, Pohang 790-784 (Korea, Republic of); Oh, Sang Ho, E-mail: shoh@postech.ac.kr [Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), San 31 Hyoja-dong, Nam-gu, Pohang 790-784 (Korea, Republic of); Koch, Christoph T. [Institute for Experimental Physics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm (Germany)

    2013-04-15

    Dark-field inline electron holography has recently been established as a convenient method to map strain in semiconductor devices, combining high precision, low noise, sub-nm spatial resolution and fields-of-view larger than 1 μm. Here we compare two approaches to reconstruct the geometric phase from a transmission electron microscopy dark-field focal series and their effects on the strain measurement: the transport-of-intensity-equation (TIE) and a flux-preserving iterative approach. For this task, we used a GaN-based light emitting diode with a highly complex heterostructure as a model system. While the TIE relies on 3 images only but requires the optimization of two free parameters (defocus step and low-limit cut-off frequency), the iterative reconstruction algorithm involves no adjustable parameters and uses images recorded at 9 different planes of focus with quadratically increasing defocus values. Optimum parameters for the TIE-reconstruction could be identified. However, the iterative phase retrieval approach yields the strain values that agree best with the expected strain levels and provides also higher spatial resolution.

  17. ChIP-seq Accurately Predicts Tissue-Specific Activity of Enhancers

    Energy Technology Data Exchange (ETDEWEB)

    Visel, Axel; Blow, Matthew J.; Li, Zirong; Zhang, Tao; Akiyama, Jennifer A.; Holt, Amy; Plajzer-Frick, Ingrid; Shoukry, Malak; Wright, Crystal; Chen, Feng; Afzal, Veena; Ren, Bing; Rubin, Edward M.; Pennacchio, Len A.

    2009-02-01

    A major yet unresolved quest in decoding the human genome is the identification of the regulatory sequences that control the spatial and temporal expression of genes. Distant-acting transcriptional enhancers are particularly challenging to uncover since they are scattered amongst the vast non-coding portion of the genome. Evolutionary sequence constraint can facilitate the discovery of enhancers, but fails to predict when and where they are active in vivo. Here, we performed chromatin immunoprecipitation with the enhancer-associated protein p300, followed by massively-parallel sequencing, to map several thousand in vivo binding sites of p300 in mouse embryonic forebrain, midbrain, and limb tissue. We tested 86 of these sequences in a transgenic mouse assay, which in nearly all cases revealed reproducible enhancer activity in those tissues predicted by p300 binding. Our results indicate that in vivo mapping of p300 binding is a highly accurate means for identifying enhancers and their associated activities and suggest that such datasets will be useful to study the role of tissue-specific enhancers in human biology and disease on a genome-wide scale.

  18. Investigation of elemental changes in brain tissues following excitotoxic injury

    International Nuclear Information System (INIS)

    Siegele, Rainer; Howell, Nicholas R.; Callaghan, Paul D.; Pastuovic, Zeljko

    2013-01-01

    Recently the ANSTO heavy ion microprobe has been used for elemental mapping of thin brain tissue sections. The fact that a very small portion of the proton energy is used for X-ray excitation combined with small variations of the major element concentrations makes μ-PIXE imaging and GeoPIXE analysis a challenging task. Excitotoxic brain injury underlies the pathology of stroke and various neurodegenerative disorders. Large fluxes in Ca +2 cytosolic concentrations are a key feature of the initiation of this pathophysiological process. In order to understand if these modifications are associated with changes in the elemental composition, several brain sections have been mapped with μ-PIXE. Increases in Ca +2 cytosolic concentrations were indicative of the pathophysiological process continuing 1 week after an initiating neural insult. We were able to measure significant variations in K and Ca concentration distribution across investigated brain tissue. These variations correlate very well with physiological changes visible in the brain tissue. Moreover, the obtained μ-PIXE results clearly demonstrate that the elemental composition changes significantly correlate with brain drauma

  19. Investigation of elemental changes in brain tissues following excitotoxic injury

    Energy Technology Data Exchange (ETDEWEB)

    Siegele, Rainer, E-mail: rns@ansto.gov.au [Institute for Environmental Research, ANSTO, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Howell, Nicholas R.; Callaghan, Paul D. [Life Sciences, ANSTO, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Pastuovic, Zeljko [Institute for Environmental Research, ANSTO, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia)

    2013-07-01

    Recently the ANSTO heavy ion microprobe has been used for elemental mapping of thin brain tissue sections. The fact that a very small portion of the proton energy is used for X-ray excitation combined with small variations of the major element concentrations makes μ-PIXE imaging and GeoPIXE analysis a challenging task. Excitotoxic brain injury underlies the pathology of stroke and various neurodegenerative disorders. Large fluxes in Ca{sup +2} cytosolic concentrations are a key feature of the initiation of this pathophysiological process. In order to understand if these modifications are associated with changes in the elemental composition, several brain sections have been mapped with μ-PIXE. Increases in Ca{sup +2} cytosolic concentrations were indicative of the pathophysiological process continuing 1 week after an initiating neural insult. We were able to measure significant variations in K and Ca concentration distribution across investigated brain tissue. These variations correlate very well with physiological changes visible in the brain tissue. Moreover, the obtained μ-PIXE results clearly demonstrate that the elemental composition changes significantly correlate with brain drauma.

  20. Optimization of phase-variation measurements in low-coherence methods: implications for OCE

    Science.gov (United States)

    Zaitsev, Vladimir Y.; Matveyev, Alexandr L.; Matveev, Lev A.; Gelikonov, Grigory V.; Sovetsky, Alexander A.; Vitkin, Alex

    2016-04-01

    Phase-resolved measurements found numerous applications in low-coherence methods, in particular in OCT-based compressional elastography, where phase-variation gradients are used for estimating strains produced by the OCT probe pressed onto the tissue. Conventionally, for the reference and deformed pixelated OCT scans, one performs comparison of phases taken from pixels with the same coordinates. This is reasonable in regions of sufficiently small sub-pixel displacements, for which the so-compared pixels contain the same scatterers. Furthermore, to avoid error-prone multiple phase unwrapping for reconstructing displacements, one have to ensure even smaller sub-wavelength displacements. This limits the allowable strains to less than ~10-4-10-3, although such weak phase gradients can be strongly corrupted by measurement noises. Here, we discuss how creation of an order of magnitude greater strains can be used for increasing the signal-to noise ratio in estimating phase gradients by obviating the phase-unwrapping procedures and reducing the influence of decorrelation noise for supra-pixel displacements. This optimized phase-variation measurement makes it possible to perform strain mapping in optical coherence elastography with exceptionally high tolerance to noises due to possibility of using significantly increased strains. We also discuss the effect of "frozen-phase zones" associated with displaced strong scatterers. This effect can result in appearance of artifacts in the form of false stiff inclusions in elastograms in the vicinity of bright scatterers in OCT scans. We present analytical arguments, numerical simulations and experimental examples illustrating the above-mentioned features of the "frozen-phase" effect and advantages of using the proposed optimized phase-variation measurement with pixel-scale displacement compensation in the compared OCT scans.

  1. Polarized light microscopy for 3-dimensional mapping of collagen fiber architecture in ocular tissues.

    Science.gov (United States)

    Yang, Bin; Jan, Ning-Jiun; Brazile, Bryn; Voorhees, Andrew; Lathrop, Kira L; Sigal, Ian A

    2018-04-06

    Collagen fibers play a central role in normal eye mechanics and pathology. In ocular tissues, collagen fibers exhibit a complex 3-dimensional (3D) fiber orientation, with both in-plane (IP) and out-of-plane (OP) orientations. Imaging techniques traditionally applied to the study of ocular tissues only quantify IP fiber orientation, providing little information on OP fiber orientation. Accurate description of the complex 3D fiber microstructures of the eye requires quantifying full 3D fiber orientation. Herein, we present 3dPLM, a technique based on polarized light microscopy developed to quantify both IP and OP collagen fiber orientations of ocular tissues. The performance of 3dPLM was examined by simulation and experimental verification and validation. The experiments demonstrated an excellent agreement between extracted and true 3D fiber orientation. Both IP and OP fiber orientations can be extracted from the sclera and the cornea, providing previously unavailable quantitative 3D measures and insight into the tissue microarchitecture. Together, the results demonstrate that 3dPLM is a powerful imaging technique for the analysis of ocular tissues. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Lenses and effective spatial resolution in macroscopic optical mapping

    International Nuclear Information System (INIS)

    Bien, Harold; Parikh, Puja; Entcheva, Emilia

    2007-01-01

    Optical mapping of excitation dynamically tracks electrical waves travelling through cardiac or brain tissue by the use of fluorescent dyes. There are several characteristics that set optical mapping apart from other imaging modalities: dynamically changing signals requiring short exposure times, dim fluorescence demanding sensitive sensors and wide fields of view (low magnification) resulting in poor optical performance. These conditions necessitate the use of optics with good light gathering ability, i.e. lenses having high numerical aperture. Previous optical mapping studies often used sensor resolution to estimate the minimum spatial feature resolvable, assuming perfect optics and infinite contrast. We examine here the influence of finite contrast and real optics on the effective spatial resolution in optical mapping under broad-field illumination for both lateral (in-plane) resolution and axial (depth) resolution of collected fluorescence signals

  3. Mapping local anisotropy axis for scattering media using backscattering Mueller matrix imaging

    Science.gov (United States)

    He, Honghui; Sun, Minghao; Zeng, Nan; Du, E.; Guo, Yihong; He, Yonghong; Ma, Hui

    2014-03-01

    Mueller matrix imaging techniques can be used to detect the micro-structure variations of superficial biological tissues, including the sizes and shapes of cells, the structures in cells, and the densities of the organelles. Many tissues contain anisotropic fibrous micro-structures, such as collagen fibers, elastin fibers, and muscle fibers. Changes of these fibrous structures are potentially good indicators for some pathological variations. In this paper, we propose a quantitative analysis technique based on Mueller matrix for mapping local anisotropy axis of scattering media. By conducting both experiments on silk sample and Monte Carlo simulation based on the sphere-cylinder scattering model (SCSM), we extract anisotropy axis parameters from different backscattering Mueller matrix elements. Moreover, we testify the possible applications of these parameters for biological tissues. The preliminary experimental results of human cancerous samples show that, these parameters are capable to map the local axis of fibers. Since many pathological changes including early stage cancers affect the well aligned structures for tissues, the experimental results indicate that these parameters can be used as potential tools in clinical applications for biomedical diagnosis purposes.

  4. Endpoint Distinctiveness Facilitates Analogical Mapping in Pigeons

    Science.gov (United States)

    Hagmann, Carl Erick; Cook, Robert G.

    2015-01-01

    Analogical thinking necessitates mapping shared relations across two separate domains. We investigated whether pigeons could learn faster with ordinal mapping of relations across two physical dimensions (circle size & choice spatial position) relative to random mapping of these relations. Pigeons were trained to relate six circular samples of different sizes to horizontally positioned choice locations in a six alternative matching-to-sample task. Three pigeons were trained in a mapped condition in which circle size mapped directly onto choice spatial position. Three other pigeons were trained in a random condition in which the relations between size and choice position were arbitrarily assigned. The mapped group showed an advantage over the random group in acquiring this task. In a subsequent second phase, reassignment, relations between the dimensions were ordinally reversed for the mapped group and re-randomized for the random group. There was no difference in how quickly matching accuracy re-emerged in the two groups, although the mapped group eventually performed more accurately. Analyses suggested this mapped advantage was likely due endpoint distinctiveness and the benefits of proximity errors during choice responding rather than a conceptual or relational advantage attributable to the common or ordinal map of the two dimensions. This potential difficulty in mapping relations across dimensions may limit the pigeons’ capacity for more advanced types of analogical reasoning. PMID:25447511

  5. Security-enhanced phase encryption assisted by nonlinear optical correlation via sparse phase

    International Nuclear Information System (INIS)

    Chen, Wen; Chen, Xudong; Wang, Xiaogang

    2015-01-01

    We propose a method for security-enhanced phase encryption assisted by a nonlinear optical correlation via a sparse phase. Optical configurations are established based on a phase retrieval algorithm for embedding an input image and the secret data into phase-only masks. We found that when one or a few phase-only masks generated during data hiding are sparse, it is possible to integrate these sparse masks into those phase-only masks generated during the encoding of the input image. Synthesized phase-only masks are used for the recovery, and sparse distributions (i.e., binary maps) for generating the incomplete phase-only masks are considered as additional parameters for the recovery of secret data. It is difficult for unauthorized receivers to know that a useful phase has been sparsely distributed in the finally generated phase-only masks for secret-data recovery. Only when the secret data are correctly verified can the input image obtained with valid keys be claimed as targeted information. (paper)

  6. Rayleigh-wave phase-velocity maps and three-dimensional shear velocity structure of the western US from local non-plane surface wave tomography

    Science.gov (United States)

    Pollitz, F.F.; Snoke, J. Arthur

    2010-01-01

    We utilize two-and-three-quarter years of vertical-component recordings made by the Transportable Array (TA) component of Earthscope to constrain three-dimensional (3-D) seismic shear wave velocity structure in the upper 200 km of the western United States. Single-taper spectral estimation is used to compile measurements of complex spectral amplitudes from 44 317 seismograms generated by 123 teleseismic events. In the first step employed to determine the Rayleigh-wave phase-velocity structure, we implement a new tomographic method, which is simpler and more robust than scattering-based methods (e.g. multi-plane surface wave tomography). The TA is effectively implemented as a large number of local arrays by defining a horizontal Gaussian smoothing distance that weights observations near a given target point. The complex spectral-amplitude measurements are interpreted with the spherical Helmholtz equation using local observations about a succession of target points, resulting in Rayleigh-wave phase-velocity maps at periods over the range of 18–125 s. The derived maps depend on the form of local fits to the Helmholtz equation, which generally involve the nonplane-wave solutions of Friederich et al. In a second step, the phase-velocity maps are used to derive 3-D shear velocity structure. The 3-D velocity images confirm details witnessed in prior body-wave and surface-wave studies and reveal new structures, including a deep (>100 km deep) high-velocity lineament, of width ∼200 km, stretching from the southern Great Valley to northern Utah that may be a relic of plate subduction or, alternatively, either a remnant of the Mojave Precambrian Province or a mantle downwelling. Mantle seismic velocity is highly correlated with heat flow, Holocene volcanism, elastic plate thickness and seismicity. This suggests that shallow mantle structure provides the heat source for associated magmatism, as well as thinning of the thermal lithosphere, leading to relatively high

  7. Vorinostat in refractory soft tissue sarcomas - Results of a multi-centre phase II trial of the German Soft Tissue Sarcoma and Bone Tumour Working Group (AIO).

    Science.gov (United States)

    Schmitt, Thomas; Mayer-Steinacker, Regine; Mayer, Frank; Grünwald, Viktor; Schütte, Jochen; Hartmann, Jörg T; Kasper, Bernd; Hüsing, Johannes; Hajda, Jacek; Ottawa, Gregor; Mechtersheimer, Gunhild; Mikus, Gerd; Burhenne, Jürgen; Lehmann, Lorenz; Heilig, Christoph E; Ho, Anthony D; Egerer, Gerlinde

    2016-09-01

    New treatment options for patients with metastatic Soft Tissue Sarcoma are urgently needed. Preclinical studies suggested activity of vorinostat, a histone deacetylase inhibitor. A multi-centre, open-label, non-randomised phase II trial to investigate the efficacy and safety of vorinostat in patients with locally advanced or metastatic Soft Tissue Sarcoma failing 1st-line anthracycline-based chemotherapy was initiated. Patients were treated with vorinostat 400 mg po qd for 28 d followed by a treatment-free period of 7 d, representing a treatment cycle of 5 weeks. Restaging was performed every three cycles or at clinical progression. Between 06/10 and 09/13, 40 Soft Tissue Sarcoma patients were treated with vorinostat at seven participating centres. Patients had received 1 (n=8, 20%), 2 (n=10, 25%) or ≥3 (n=22, 55%) previous lines of chemotherapy. Best response after three cycles of treatment was stable disease (n=9, 23%). Median progression-free survival and overall survival were 3.2 and 12.3 months, respectively. Six patients showed long-lasting disease stabilisation for up to ten cycles. Statistical analyses failed to identify baseline predictive markers in this subgroup. Major toxicities (grade ≥III) included haematological toxicity (n=6, 15%) gastrointestinal disorders (n=5, 13%), fatigue (n=4, 10%), musculoskeletal pain (n=4, 10%), and pneumonia (n=2, 5%). In a heavily pre-treated patient population, objective response to vorinostat was low. However, a small subgroup of patients had long-lasting disease stabilisation. Further studies aiming to identify predictive markers for treatment response as well as exploration of combination regimens are warranted. NCT00918489 (ClinicalTrials.gov) EudraCT-number: 2008-008513-19. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Frequency-locked pulse sequencer for high-frame-rate monochromatic tissue motion imaging.

    Science.gov (United States)

    Azar, Reza Zahiri; Baghani, Ali; Salcudean, Septimiu E; Rohling, Robert

    2011-04-01

    To overcome the inherent low frame rate of conventional ultrasound, we have previously presented a system that can be implemented on conventional ultrasound scanners for high-frame-rate imaging of monochromatic tissue motion. The system employs a sector subdivision technique in the sequencer to increase the acquisition rate. To eliminate the delays introduced during data acquisition, a motion phase correction algorithm has also been introduced to create in-phase displacement images. Previous experimental results from tissue- mimicking phantoms showed that the system can achieve effective frame rates of up to a few kilohertz on conventional ultrasound systems. In this short communication, we present a new pulse sequencing strategy that facilitates high-frame-rate imaging of monochromatic motion such that the acquired echo signals are inherently in-phase. The sequencer uses the knowledge of the excitation frequency to synchronize the acquisition of the entire imaging plane to that of an external exciter. This sequencing approach eliminates any need for synchronization or phase correction and has applications in tissue elastography, which we demonstrate with tissue-mimicking phantoms. © 2011 IEEE

  9. Least-squares calibration method based on a universal phase and height mapping formula in Fourier transform profilometry

    International Nuclear Information System (INIS)

    Wen, Yongfu; Cheng, Haobo; Gao, Ya; Zhang, Huijing; Feng, Yunpeng; Pan, Baozhu

    2011-01-01

    In Fourier transform profilometry (FTP), we perform a strict theoretical analysis of the phase–height mapping relationship and give a universal calculation formula in which the constraints on the experimental setup are removed. In that case, the projector and camera can be located arbitrarily to get better information on fringes, which makes the system easy to manipulate and improves the speed of measurement. As the relationship between the phase and height distribution depends on system parameters (such as the relative position of the projector and camera) which are difficult to obtain, we propose a least-squares calibration approach for FTP, which can avoid measuring the system parameters directly. Both the simulation and experimental results prove that the 3D shape of the tested objects can be reconstructed exactly by using the calculation formula and calibration method, and that the system has better universality

  10. Evaluation of impedance on biological Tissues using automatic control measurement system

    Energy Technology Data Exchange (ETDEWEB)

    Kil, Sang Hyeong; Shin, Dong Hoon; Lee, Seong Mo [Pusan National University, Yangsan (Korea, Republic of); Lee, Moo Seok; Kim, Sang Sik [Pusan National University, Busan (Korea, Republic of); Kim, Gun FDo; Lee, Jong Kyu [Pukyung National University, Busan (Korea, Republic of)

    2015-08-15

    Each biological tissue has endemic electrical characteristics owing to various differences such as those in cellular arrangement or organization form. The endemic electrical characteristics change when any biological change occurs. This work is a preliminary study surveying the changes in the electrical characteristics of biological tissue caused by radiation exposure. For protection against radiation hazards, therefore the electrical characteristics of living tissue were evaluated after development of the automatic control measurement system using LabVIEW. No alteration of biological tissues was observed before and after measurement of the electrical characteristics, and the biological tissues exhibited similar patterns. Through repeated measurements using the impedance/gain-phase analyzer, the coefficient of variation was determined as within 10%. The reproducibility impedance phase difference in electrical characteristics of the biological tissue did not change, and the tissue had resistance. The absolute value of impedance decreased constantly in proportion to the frequency. It has become possible to understand the electrical characteristics of biological tissues through the measurements made possible by the use of the developed.

  11. Evaluation of impedance on biological Tissues using automatic control measurement system

    International Nuclear Information System (INIS)

    Kil, Sang Hyeong; Shin, Dong Hoon; Lee, Seong Mo; Lee, Moo Seok; Kim, Sang Sik; Kim, Gun FDo; Lee, Jong Kyu

    2015-01-01

    Each biological tissue has endemic electrical characteristics owing to various differences such as those in cellular arrangement or organization form. The endemic electrical characteristics change when any biological change occurs. This work is a preliminary study surveying the changes in the electrical characteristics of biological tissue caused by radiation exposure. For protection against radiation hazards, therefore the electrical characteristics of living tissue were evaluated after development of the automatic control measurement system using LabVIEW. No alteration of biological tissues was observed before and after measurement of the electrical characteristics, and the biological tissues exhibited similar patterns. Through repeated measurements using the impedance/gain-phase analyzer, the coefficient of variation was determined as within 10%. The reproducibility impedance phase difference in electrical characteristics of the biological tissue did not change, and the tissue had resistance. The absolute value of impedance decreased constantly in proportion to the frequency. It has become possible to understand the electrical characteristics of biological tissues through the measurements made possible by the use of the developed.

  12. Optical histology: a method to visualize microvasculature in thick tissue sections of mouse brain.

    Directory of Open Access Journals (Sweden)

    Austin J Moy

    Full Text Available The microvasculature is the network of blood vessels involved in delivering nutrients and gases necessary for tissue survival. Study of the microvasculature often involves immunohistological methods. While useful for visualizing microvasculature at the µm scale in specific regions of interest, immunohistology is not well suited to visualize the global microvascular architecture in an organ. Hence, use of immunohistology precludes visualization of the entire microvasculature of an organ, and thus impedes study of global changes in the microvasculature that occur in concert with changes in tissue due to various disease states. Therefore, there is a critical need for a simple, relatively rapid technique that will facilitate visualization of the microvascular network of an entire tissue.The systemic vasculature of a mouse is stained with the fluorescent lipophilic dye DiI using a method called "vessel painting". The brain, or other organ of interest, is harvested and fixed in 4% paraformaldehyde. The organ is then sliced into 1 mm sections and optically cleared, or made transparent, using FocusClear, a proprietary optical clearing agent. After optical clearing, the DiI-labeled tissue microvasculature is imaged using confocal fluorescence microscopy and adjacent image stacks tiled together to produce a depth-encoded map of the microvasculature in the tissue slice. We demonstrated that the use of optical clearing enhances both the tissue imaging depth and the estimate of the vascular density. Using our "optical histology" technique, we visualized microvasculature in the mouse brain to a depth of 850 µm.Presented here are maps of the microvasculature in 1 mm thick slices of mouse brain. Using combined optical clearing and optical imaging techniques, we devised a methodology to enhance the visualization of the microvasculature in thick tissues. We believe this technique could potentially be used to generate a three-dimensional map of the

  13. Refrigeration. Two-Phase Flow. Flow Regimes and Pressure Drop

    DEFF Research Database (Denmark)

    Knudsen, Hans-Jørgen Høgaard

    2002-01-01

    The note gives the basic definitions used in two-phase flow. Flow regimes and flow regimes map are introduced. The different contributions to the pressure drop are stated together with an imperical correlation from the litterature.......The note gives the basic definitions used in two-phase flow. Flow regimes and flow regimes map are introduced. The different contributions to the pressure drop are stated together with an imperical correlation from the litterature....

  14. Whole slide imaging of unstained tissue using lensfree microscopy

    Science.gov (United States)

    Morel, Sophie Nhu An; Hervé, Lionel; Bordy, Thomas; Cioni, Olivier; Delon, Antoine; Fromentin, Catherine; Dinten, Jean-Marc; Allier, Cédric

    2016-04-01

    Pathologist examination of tissue slides provides insightful information about a patient's disease. Traditional analysis of tissue slides is performed under a binocular microscope, which requires staining of the sample and delays the examination. We present a simple cost-effective lensfree imaging method to record 2-4μm resolution wide-field (10 mm2 to 6 cm2) images of unstained tissue slides. The sample processing time is reduced as there is no need for staining. A wide field of view (10 mm2) lensfree hologram is recorded in a single shot and the image is reconstructed in 2s providing a very fast acquisition chain. The acquisition is multispectral, i.e. multiple holograms are recorded simultaneously at three different wavelengths, and a dedicated holographic reconstruction algorithm is used to retrieve both amplitude and phase. Whole tissue slides imaging is obtained by recording 130 holograms with X-Y translation stages and by computing the mosaic of a 25 x 25 mm2 reconstructed image. The reconstructed phase provides a phase-contrast-like image of the unstained specimen, revealing structures of healthy and diseased tissue. Slides from various organs can be reconstructed, e.g. lung, colon, ganglion, etc. To our knowledge, our method is the first technique that enables fast wide-field lensfree imaging of such unlabeled dense samples. This technique is much cheaper and compact than a conventional phase contrast microscope and could be made portable. In sum, we present a new methodology that could quickly provide useful information when a rapid diagnosis is needed, such as tumor margin identification on frozen section biopsies during surgery.

  15. Mechanical modulation of nascent stem cell lineage commitment in tissue engineering scaffolds.

    Science.gov (United States)

    Song, Min Jae; Dean, David; Knothe Tate, Melissa L

    2013-07-01

    Taking inspiration from tissue morphogenesis in utero, this study tests the concept of using tissue engineering scaffolds as delivery devices to modulate emergent structure-function relationships at early stages of tissue genesis. We report on the use of a combined computational fluid dynamics (CFD) modeling, advanced manufacturing methods, and experimental fluid mechanics (micro-piv and strain mapping) for the prospective design of tissue engineering scaffold geometries that deliver spatially resolved mechanical cues to stem cells seeded within. When subjected to a constant magnitude global flow regime, the local scaffold geometry dictates the magnitudes of mechanical stresses and strains experienced by a given cell, and in a spatially resolved fashion, similar to patterning during morphogenesis. In addition, early markers of mesenchymal stem cell lineage commitment relate significantly to the local mechanical environment of the cell. Finally, by plotting the range of stress-strain states for all data corresponding to nascent cell lineage commitment (95% CI), we begin to "map the mechanome", defining stress-strain states most conducive to targeted cell fates. In sum, we provide a library of reference mechanical cues that can be delivered to cells seeded on tissue engineering scaffolds to guide target tissue phenotypes in a temporally and spatially resolved manner. Knowledge of these effects allows for prospective scaffold design optimization using virtual models prior to prototyping and clinical implementation. Finally, this approach enables the development of next generation scaffolds cum delivery devices for genesis of complex tissues with heterogenous properties, e.g., organs, joints or interface tissues such as growth plates. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Statistical characterization of the standard map

    Science.gov (United States)

    Ruiz, Guiomar; Tirnakli, Ugur; Borges, Ernesto P.; Tsallis, Constantino

    2017-06-01

    The standard map, paradigmatic conservative system in the (x, p) phase space, has been recently shown (Tirnakli and Borges (2016 Sci. Rep. 6 23644)) to exhibit interesting statistical behaviors directly related to the value of the standard map external parameter K. A comprehensive statistical numerical description is achieved in the present paper. More precisely, for large values of K (e.g. K  =  10) where the Lyapunov exponents are neatly positive over virtually the entire phase space consistently with Boltzmann-Gibbs (BG) statistics, we verify that the q-generalized indices related to the entropy production q{ent} , the sensitivity to initial conditions q{sen} , the distribution of a time-averaged (over successive iterations) phase-space coordinate q{stat} , and the relaxation to the equilibrium final state q{rel} , collapse onto a fixed point, i.e. q{ent}=q{sen}=q{stat}=q{rel}=1 . In remarkable contrast, for small values of K (e.g. K  =  0.2) where the Lyapunov exponents are virtually zero over the entire phase space, we verify q{ent}=q{sen}=0 , q{stat} ≃ 1.935 , and q{rel} ≃1.4 . The situation corresponding to intermediate values of K, where both stable orbits and a chaotic sea are present, is discussed as well. The present results transparently illustrate when BG behavior and/or q-statistical behavior are observed.

  17. Automatic Mapping Extraction from Multiecho T2-Star Weighted Magnetic Resonance Images for Improving Morphological Evaluations in Human Brain

    Directory of Open Access Journals (Sweden)

    Shaode Yu

    2013-01-01

    Full Text Available Mapping extraction is useful in medical image analysis. Similarity coefficient mapping (SCM replaced signal response to time course in tissue similarity mapping with signal response to TE changes in multiecho T2-star weighted magnetic resonance imaging without contrast agent. Since different tissues are with different sensitivities to reference signals, a new algorithm is proposed by adding a sensitivity index to SCM. It generates two mappings. One measures relative signal strength (SSM and the other depicts fluctuation magnitude (FMM. Meanwhile, the new method is adaptive to generate a proper reference signal by maximizing the sum of contrast index (CI from SSM and FMM without manual delineation. Based on four groups of images from multiecho T2-star weighted magnetic resonance imaging, the capacity of SSM and FMM in enhancing image contrast and morphological evaluation is validated. Average contrast improvement index (CII of SSM is 1.57, 1.38, 1.34, and 1.41. Average CII of FMM is 2.42, 2.30, 2.24, and 2.35. Visual analysis of regions of interest demonstrates that SSM and FMM show better morphological structures than original images, T2-star mapping and SCM. These extracted mappings can be further applied in information fusion, signal investigation, and tissue segmentation.

  18. Dual-energy X-ray absorptiometry: analysis of pediatric fat estimate errors due to tissue hydration effects.

    Science.gov (United States)

    Testolin, C G; Gore, R; Rivkin, T; Horlick, M; Arbo, J; Wang, Z; Chiumello, G; Heymsfield, S B

    2000-12-01

    Dual-energy X-ray absorptiometry (DXA) percent (%) fat estimates may be inaccurate in young children, who typically have high tissue hydration levels. This study was designed to provide a comprehensive analysis of pediatric tissue hydration effects on DXA %fat estimates. Phase 1 was experimental and included three in vitro studies to establish the physical basis of DXA %fat-estimation models. Phase 2 extended phase 1 models and consisted of theoretical calculations to estimate the %fat errors emanating from previously reported pediatric hydration effects. Phase 1 experiments supported the two-compartment DXA soft tissue model and established that pixel ratio of low to high energy (R values) are a predictable function of tissue elemental content. In phase 2, modeling of reference body composition values from birth to age 120 mo revealed that %fat errors will arise if a "constant" adult lean soft tissue R value is applied to the pediatric population; the maximum %fat error, approximately 0.8%, would be present at birth. High tissue hydration, as observed in infants and young children, leads to errors in DXA %fat estimates. The magnitude of these errors based on theoretical calculations is small and may not be of clinical or research significance.

  19. The role of the endocrine system in feeding-induced tissue-specific circadian entrainment.

    Science.gov (United States)

    Sato, Miho; Murakami, Mariko; Node, Koichi; Matsumura, Ritsuko; Akashi, Makoto

    2014-07-24

    The circadian clock is entrained to environmental cycles by external cue-mediated phase adjustment. Although the light input pathway has been well defined, the mechanism of feeding-induced phase resetting remains unclear. The tissue-specific sensitivity of peripheral entrainment to feeding suggests the involvement of multiple pathways, including humoral and neuronal signals. Previous in vitro studies with cultured cells indicate that endocrine factors may function as entrainment cues for peripheral clocks. However, blood-borne factors that are well characterized in actual feeding-induced resetting have yet to be identified. Here, we report that insulin may be involved in feeding-induced tissue-type-dependent entrainment in vivo. In ex vivo culture experiments, insulin-induced phase shift in peripheral clocks was dependent on tissue type, which was consistent with tissue-specific insulin sensitivity, and peripheral entrainment in insulin-sensitive tissues involved PI3K- and MAPK-mediated signaling pathways. These results suggest that insulin may be an immediate early factor in feeding-mediated tissue-specific entrainment. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  20. Global mapping of transposon location.

    Directory of Open Access Journals (Sweden)

    Abram Gabriel

    2006-12-01

    Full Text Available Transposable genetic elements are ubiquitous, yet their presence or absence at any given position within a genome can vary between individual cells, tissues, or strains. Transposable elements have profound impacts on host genomes by altering gene expression, assisting in genomic rearrangements, causing insertional mutations, and serving as sources of phenotypic variation. Characterizing a genome's full complement of transposons requires whole genome sequencing, precluding simple studies of the impact of transposition on interindividual variation. Here, we describe a global mapping approach for identifying transposon locations in any genome, using a combination of transposon-specific DNA extraction and microarray-based comparative hybridization analysis. We use this approach to map the repertoire of endogenous transposons in different laboratory strains of Saccharomyces cerevisiae and demonstrate that transposons are a source of extensive genomic variation. We also apply this method to mapping bacterial transposon insertion sites in a yeast genomic library. This unique whole genome view of transposon location will facilitate our exploration of transposon dynamics, as well as defining bases for individual differences and adaptive potential.

  1. Momentum Maps and Stochastic Clebsch Action Principles

    Science.gov (United States)

    Cruzeiro, Ana Bela; Holm, Darryl D.; Ratiu, Tudor S.

    2018-01-01

    We derive stochastic differential equations whose solutions follow the flow of a stochastic nonlinear Lie algebra operation on a configuration manifold. For this purpose, we develop a stochastic Clebsch action principle, in which the noise couples to the phase space variables through a momentum map. This special coupling simplifies the structure of the resulting stochastic Hamilton equations for the momentum map. In particular, these stochastic Hamilton equations collectivize for Hamiltonians that depend only on the momentum map variable. The Stratonovich equations are derived from the Clebsch variational principle and then converted into Itô form. In comparing the Stratonovich and Itô forms of the stochastic dynamical equations governing the components of the momentum map, we find that the Itô contraction term turns out to be a double Poisson bracket. Finally, we present the stochastic Hamiltonian formulation of the collectivized momentum map dynamics and derive the corresponding Kolmogorov forward and backward equations.

  2. Maps of Fe-Al phases formation kinetics parameters during isothermal sintering

    Energy Technology Data Exchange (ETDEWEB)

    Pochec, Ewelina, E-mail: epochec@wat.edu.pl [Department of Advanced Materials and Technology, Military University of Technology (Poland); Jozwiak, Stanislaw; Karczewski, Krzysztof; Bojar, Zbigniew [Department of Advanced Materials and Technology, Military University of Technology (Poland)

    2012-10-10

    Highlights: Black-Right-Pointing-Pointer The sintering temperature and compaction pressure have a strong influence on the sinters structure. Black-Right-Pointing-Pointer The measurements confirmed the presence of the high-aluminium phases from Fe-Al equilibrium system in tested sinters. Black-Right-Pointing-Pointer The kinetics of Fe-Al phase formation can be described by Johnson-Mehl-Avrami modelling. - Abstract: The influence of technological parameters (compaction pressure and sintering temperature) on Fe-Al phase formation was investigated. The kinetics of phase transformation preceding and during an SHS reaction was studied in isothermal conditions by DSC using the JMA (Johnson-Mehl-Avrami) model. This model allowed us to determine basic kinetic parameters, including the Avrami exponent, which characterises the rate and manner of particular phase nucleation. The activation energy (E{sub a}) of particular phase formation was determined by the Kissinger method. XRD analysis and SEM observations of sintered material showed that not only Fe{sub 2}Al{sub 5} phase and low-aluminium solid solution in iron but also aluminium-rich FeAl{sub 2} and FeAl{sub 3} phases are formed during the sintering of an FeAl50 elementary powder mixture in isothermal conditions with an SHS reaction. The above conclusions were confirmed by iron-based solid solution lattice parameter studies and microhardness measurements.

  3. Detection, mapping, and quantification of single walled carbon nanotubes in histological specimens with photoacoustic microscopy.

    NARCIS (Netherlands)

    Avti, P.K.; Hu, S.; Favazza, C.; Mikos, A.G.; Jansen, J.A.; Shroyer, K.R.; Wang, L.V.; Sitharaman, B.

    2012-01-01

    AIMS: In the present study, the efficacy of multi-scale photoacoustic microscopy (PAM) was investigated to detect, map, and quantify trace amounts [nanograms (ng) to micrograms (microg)] of SWCNTs in a variety of histological tissue specimens consisting of cancer and benign tissue biopsies

  4. Encoding methods for B1+ mapping in parallel transmit systems at ultra high field

    Science.gov (United States)

    Tse, Desmond H. Y.; Poole, Michael S.; Magill, Arthur W.; Felder, Jörg; Brenner, Daniel; Jon Shah, N.

    2014-08-01

    Parallel radiofrequency (RF) transmission, either in the form of RF shimming or pulse design, has been proposed as a solution to the B1+ inhomogeneity problem in ultra high field magnetic resonance imaging. As a prerequisite, accurate B1+ maps from each of the available transmit channels are required. In this work, four different encoding methods for B1+ mapping, namely 1-channel-on, all-channels-on-except-1, all-channels-on-1-inverted and Fourier phase encoding, were evaluated using dual refocusing acquisition mode (DREAM) at 9.4 T. Fourier phase encoding was demonstrated in both phantom and in vivo to be the least susceptible to artefacts caused by destructive RF interference at 9.4 T. Unlike the other two interferometric encoding schemes, Fourier phase encoding showed negligible dependency on the initial RF phase setting and therefore no prior B1+ knowledge is required. Fourier phase encoding also provides a flexible way to increase the number of measurements to increase SNR, and to allow further reduction of artefacts by weighted decoding. These advantages of Fourier phase encoding suggest that it is a good choice for B1+ mapping in parallel transmit systems at ultra high field.

  5. Cerebral Metabolic Rate of Oxygen (CMRO2 ) Mapping by Combining Quantitative Susceptibility Mapping (QSM) and Quantitative Blood Oxygenation Level-Dependent Imaging (qBOLD).

    Science.gov (United States)

    Cho, Junghun; Kee, Youngwook; Spincemaille, Pascal; Nguyen, Thanh D; Zhang, Jingwei; Gupta, Ajay; Zhang, Shun; Wang, Yi

    2018-03-07

    To map the cerebral metabolic rate of oxygen (CMRO 2 ) by estimating the oxygen extraction fraction (OEF) from gradient echo imaging (GRE) using phase and magnitude of the GRE data. 3D multi-echo gradient echo imaging and perfusion imaging with arterial spin labeling were performed in 11 healthy subjects. CMRO 2 and OEF maps were reconstructed by joint quantitative susceptibility mapping (QSM) to process GRE phases and quantitative blood oxygen level-dependent (qBOLD) modeling to process GRE magnitudes. Comparisons with QSM and qBOLD alone were performed using ROI analysis, paired t-tests, and Bland-Altman plot. The average CMRO 2 value in cortical gray matter across subjects were 140.4 ± 14.9, 134.1 ± 12.5, and 184.6 ± 17.9 μmol/100 g/min, with corresponding OEFs of 30.9 ± 3.4%, 30.0 ± 1.8%, and 40.9 ± 2.4% for methods based on QSM, qBOLD, and QSM+qBOLD, respectively. QSM+qBOLD provided the highest CMRO 2 contrast between gray and white matter, more uniform OEF than QSM, and less noisy OEF than qBOLD. Quantitative CMRO 2 mapping that fits the entire complex GRE data is feasible by combining QSM analysis of phase and qBOLD analysis of magnitude. © 2018 International Society for Magnetic Resonance in Medicine.

  6. Quantitative X-ray mapping, scatter diagrams and the generation of correction maps to obtain more information about your material

    Science.gov (United States)

    Wuhrer, R.; Moran, K.

    2014-03-01

    Quantitative X-ray mapping with silicon drift detectors and multi-EDS detector systems have become an invaluable analysis technique and one of the most useful methods of X-ray microanalysis today. The time to perform an X-ray map has reduced considerably with the ability to map minor and trace elements very accurately due to the larger detector area and higher count rate detectors. Live X-ray imaging can now be performed with a significant amount of data collected in a matter of minutes. A great deal of information can be obtained from X-ray maps. This includes; elemental relationship or scatter diagram creation, elemental ratio mapping, chemical phase mapping (CPM) and quantitative X-ray maps. In obtaining quantitative x-ray maps, we are able to easily generate atomic number (Z), absorption (A), fluorescence (F), theoretical back scatter coefficient (η), and quantitative total maps from each pixel in the image. This allows us to generate an image corresponding to each factor (for each element present). These images allow the user to predict and verify where they are likely to have problems in our images, and are especially helpful to look at possible interface artefacts. The post-processing techniques to improve the quantitation of X-ray map data and the development of post processing techniques for improved characterisation are covered in this paper.

  7. Quantitative X-ray mapping, scatter diagrams and the generation of correction maps to obtain more information about your material

    International Nuclear Information System (INIS)

    Wuhrer, R; Moran, K

    2014-01-01

    Quantitative X-ray mapping with silicon drift detectors and multi-EDS detector systems have become an invaluable analysis technique and one of the most useful methods of X-ray microanalysis today. The time to perform an X-ray map has reduced considerably with the ability to map minor and trace elements very accurately due to the larger detector area and higher count rate detectors. Live X-ray imaging can now be performed with a significant amount of data collected in a matter of minutes. A great deal of information can be obtained from X-ray maps. This includes; elemental relationship or scatter diagram creation, elemental ratio mapping, chemical phase mapping (CPM) and quantitative X-ray maps. In obtaining quantitative x-ray maps, we are able to easily generate atomic number (Z), absorption (A), fluorescence (F), theoretical back scatter coefficient (η), and quantitative total maps from each pixel in the image. This allows us to generate an image corresponding to each factor (for each element present). These images allow the user to predict and verify where they are likely to have problems in our images, and are especially helpful to look at possible interface artefacts. The post-processing techniques to improve the quantitation of X-ray map data and the development of post processing techniques for improved characterisation are covered in this paper

  8. Atomically resolved tissue integration.

    Science.gov (United States)

    Karlsson, Johan; Sundell, Gustav; Thuvander, Mattias; Andersson, Martin

    2014-08-13

    In the field of biomedical technology, a critical aspect is the ability to control and understand the integration of an implantable device in living tissue. Despite the technical advances in the development of biomaterials, the elaborate interplay encompassing materials science and biology on the atomic level is not very well understood. Within implantology, anchoring a biomaterial device into bone tissue is termed osseointegration. In the most accepted theory, osseointegration is defined as an interfacial bonding between implant and bone; however, there is lack of experimental evidence to confirm this. Here we show that atom probe tomography can be used to study the implant-tissue interaction, allowing for three-dimensional atomic mapping of the interface region. Interestingly, our analyses demonstrated that direct contact between Ca atoms and the implanted titanium oxide surface is formed without the presence of a protein interlayer, which means that a pure inorganic interface is created, hence giving experimental support to the current theory of osseointegration. We foresee that this result will be of importance in the development of future biomaterials as well as in the design of in vitro evaluation techniques.

  9. The SafeBoosC Phase II Randomised Clinical Trial : A Treatment Guideline for Targeted Near-Infrared-Derived Cerebral Tissue Oxygenation versus Standard Treatment in Extremely Preterm Infants

    NARCIS (Netherlands)

    Pellicer, Adelina; Greisen, Gorm; Benders, Manon; Claris, Olivier; Dempsey, Eugene; Fumagalli, Monica; Gluud, Christian; Hagmann, Cornelia; Hellstroem-Westas, Lena; Hyttel-Sorensen, Simon; Lemmers, Petra; Naulaers, Gunnar; Pichler, Gerhard; Roll, Claudia; van Bel, Frank; van Oeveren, Wim; Skoog, Maria; Wolf, Martin; Austin, Topun

    2013-01-01

    Near-infrared spectroscopy-derived regional tissue oxygen saturation of haemoglobin (rSto(2)) reflects venous oxygen saturation. If cerebral metabolism is stable, rSto(2) can be used as an estimate of cerebral oxygen delivery. The SafeBoosC phase II randomised clinical trial hypothesises that the

  10. Endpoint distinctiveness facilitates analogical mapping in pigeons.

    Science.gov (United States)

    Hagmann, Carl Erick; Cook, Robert G

    2015-03-01

    Analogical thinking necessitates mapping shared relations across two separate domains. We investigated whether pigeons could learn faster with ordinal mapping of relations across two physical dimensions (circle size & choice spatial position) relative to random mapping of these relations. Pigeons were trained to relate six circular samples of different sizes to horizontally positioned choice locations in a six alternative matching-to-sample task. Three pigeons were trained in a mapped condition in which circle size mapped directly onto choice spatial position. Three other pigeons were trained in a random condition in which the relations between size and choice position were arbitrarily assigned. The mapped group showed an advantage over the random group in acquiring this task. In a subsequent second phase, relations between the dimensions were ordinally reversed for the mapped group and re-randomized for the random group. There was no difference in how quickly matching accuracy re-emerged in the two groups, although the mapped group eventually performed more accurately. Analyses suggested this mapped advantage was likely due to endpoint distinctiveness and the benefits of proximity errors during choice responding rather than a conceptual or relational advantage attributable to the common or ordinal mapping of the two dimensions. This potential difficulty in mapping relations across dimensions may limit the pigeons' capacity for more advanced types of analogical reasoning. This article is part of a Special Issue entitled: Tribute to Tom Zentall. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Mass spectrometry imaging enriches biomarker discovery approaches with candidate mapping.

    Science.gov (United States)

    Scott, Alison J; Jones, Jace W; Orschell, Christie M; MacVittie, Thomas J; Kane, Maureen A; Ernst, Robert K

    2014-01-01

    Integral to the characterization of radiation-induced tissue damage is the identification of unique biomarkers. Biomarker discovery is a challenging and complex endeavor requiring both sophisticated experimental design and accessible technology. The resources within the National Institute of Allergy and Infectious Diseases (NIAID)-sponsored Consortium, Medical Countermeasures Against Radiological Threats (MCART), allow for leveraging robust animal models with novel molecular imaging techniques. One such imaging technique, MALDI (matrix-assisted laser desorption ionization) mass spectrometry imaging (MSI), allows for the direct spatial visualization of lipids, proteins, small molecules, and drugs/drug metabolites-or biomarkers-in an unbiased manner. MALDI-MSI acquires mass spectra directly from an intact tissue slice in discrete locations across an x, y grid that are then rendered into a spatial distribution map composed of ion mass and intensity. The unique mass signals can be plotted to generate a spatial map of biomarkers that reflects pathology and molecular events. The crucial unanswered questions that can be addressed with MALDI-MSI include identification of biomarkers for radiation damage that reflect the response to radiation dose over time and the efficacy of therapeutic interventions. Techniques in MALDI-MSI also enable integration of biomarker identification among diverse animal models. Analysis of early, sublethally irradiated tissue injury samples from diverse mouse tissues (lung and ileum) shows membrane phospholipid signatures correlated with histological features of these unique tissues. This paper will discuss the application of MALDI-MSI for use in a larger biomarker discovery pipeline.

  12. Evaluation of early tissue reactions after lumbar intertransverse process fusion using CT in a rabbit

    International Nuclear Information System (INIS)

    Shinbo, Jun; Mainil-Varlet, Pierre; Watanabe, Atsuya; Pippig, Suzanne; Koener, Jens; Anderson, Suzanne E.

    2010-01-01

    The objective of the study was to evaluate tissue reactions such as bone genesis, cartilage genesis and graft materials in the early phase of lumbar intertransverse process fusion in a rabbit model using computed tomography (CT) imaging with CT intensity (Hounsfield units) measurement, and to compare these data with histological results. Lumbar intertransverse process fusion was performed on 18 rabbits. Four graft materials were used: autograft bone (n=3); collagen membrane soaked with recombinant human bone morphogenetic protein-2 (rhBMP-2) (n=5); granular calcium phosphate (n=5); and granular calcium phosphate coated with rhBMP-2 (n=5). All rabbits were euthanized 3 weeks post-operatively and lumbar spines were removed for CT imaging and histological examination. Computed tomography imaging demonstrated that each fusion mass component had the appropriate CT intensity range. CT also showed the different distributions and intensities of bone genesis in the fusion masses between the groups. Each component of tissue reactions was identified successfully on CT images using the CT intensity difference. Using CT color mapping, these observations could be easily visualized, and the results correlated well with histological findings. The use of CT intensity is an effective approach for observing and comparing early tissue reactions such as newly synthesized bone, newly synthesized cartilage, and graft materials after lumbar intertransverse process fusion in a rabbit model. (orig.)

  13. A real time QRS detection using delay-coordinate mapping for the microcontroller implementation.

    Science.gov (United States)

    Lee, Jeong-Whan; Kim, Kyeong-Seop; Lee, Bongsoo; Lee, Byungchae; Lee, Myoung-Ho

    2002-01-01

    In this article, we propose a new algorithm using the characteristics of reconstructed phase portraits by delay-coordinate mapping utilizing lag rotundity for a real-time detection of QRS complexes in ECG signals. In reconstructing phase portrait the mapping parameters, time delay, and mapping dimension play important roles in shaping of portraits drawn in a new dimensional space. Experimentally, the optimal mapping time delay for detection of QRS complexes turned out to be 20 ms. To explore the meaning of this time delay and the proper mapping dimension, we applied a fill factor, mutual information, and autocorrelation function algorithm that were generally used to analyze the chaotic characteristics of sampled signals. From these results, we could find the fact that the performance of our proposed algorithms relied mainly on the geometrical property such as an area of the reconstructed phase portrait. For the real application, we applied our algorithm for designing a small cardiac event recorder. This system was to record patients' ECG and R-R intervals for 1 h to investigate HRV characteristics of the patients who had vasovagal syncope symptom and for the evaluation, we implemented our algorithm in C language and applied to MIT/BIH arrhythmia database of 48 subjects. Our proposed algorithm achieved a 99.58% detection rate of QRS complexes.

  14. Chaos and Fractals in C-K Map

    Science.gov (United States)

    Wang, Xing-Yuan; Liang, Qing-Yong; Meng, Juan

    The characteristic of the fixed points of the Carotid-Kundalini (C-K) map is investigated and the boundary equation of the first bifurcation of the C-K map in the parameter plane is given. Based on the studies of the phase graph, the power spectrum, the correlation dimension and the Lyapunov exponents, the paper reveals the general features of the C-K map transforming from regularity. Meanwhile, using the periodic scanning technology proposed by Welstead and Cromer, a series of Mandelbrot-Julia (M-J) sets of the complex C-K map are constructed. The symmetry of M-J set and the topological inflexibility of distributing of periodic region in the Mandelbrot set are investigated. By founding the whole portray of Julia sets based on Mandelbrot set qualitatively, we find out that Mandelbrot sets contain abundant information of structure of Julia sets.

  15. Exact area devil's staircase for the sawtooth map

    International Nuclear Information System (INIS)

    Chen, Q.; Meiss, J.D.

    1988-04-01

    The sawtooth mapping is a family of uniformly hyperbolic, piecewise linear, area-preserving maps on the cylinder. We construct the resonances, cantori, and turnstiles of this family and derive exact formulas for the resonance areas and the escaping fluxes. These are of prime interst for an understanding of the deterministic transport which occurs the stochastic regime. The resonances are shown to fill the full measure of phase space. 9 refs., 4 figs

  16. LungMAP: The Molecular Atlas of Lung Development Program.

    Science.gov (United States)

    Ardini-Poleske, Maryanne E; Clark, Robert F; Ansong, Charles; Carson, James P; Corley, Richard A; Deutsch, Gail H; Hagood, James S; Kaminski, Naftali; Mariani, Thomas J; Potter, Steven S; Pryhuber, Gloria S; Warburton, David; Whitsett, Jeffrey A; Palmer, Scott M; Ambalavanan, Namasivayam

    2017-11-01

    The National Heart, Lung, and Blood Institute is funding an effort to create a molecular atlas of the developing lung (LungMAP) to serve as a research resource and public education tool. The lung is a complex organ with lengthy development time driven by interactive gene networks and dynamic cross talk among multiple cell types to control and coordinate lineage specification, cell proliferation, differentiation, migration, morphogenesis, and injury repair. A better understanding of the processes that regulate lung development, particularly alveologenesis, will have a significant impact on survival rates for premature infants born with incomplete lung development and will facilitate lung injury repair and regeneration in adults. A consortium of four research centers, a data coordinating center, and a human tissue repository provides high-quality molecular data of developing human and mouse lungs. LungMAP includes mouse and human data for cross correlation of developmental processes across species. LungMAP is generating foundational data and analysis, creating a web portal for presentation of results and public sharing of data sets, establishing a repository of young human lung tissues obtained through organ donor organizations, and developing a comprehensive lung ontology that incorporates the latest findings of the consortium. The LungMAP website (www.lungmap.net) currently contains more than 6,000 high-resolution lung images and transcriptomic, proteomic, and lipidomic human and mouse data and provides scientific information to stimulate interest in research careers for young audiences. This paper presents a brief description of research conducted by the consortium, database, and portal development and upcoming features that will enhance the LungMAP experience for a community of users. Copyright © 2017 the American Physiological Society.

  17. Diffusion weighted imaging demystified. The technique and potential clinical applications for soft tissue imaging

    International Nuclear Information System (INIS)

    Ahlawat, Shivani; Fayad, Laura M.

    2018-01-01

    Diffusion-weighted imaging (DWI) is a fast, non-contrast technique that is readily available and easy to integrate into an existing imaging protocol. DWI with apparent diffusion coefficient (ADC) mapping offers a quantitative metric for soft tissue evaluation and provides information regarding the cellularity of a region of interest. There are several available methods of performing DWI, and artifacts and pitfalls must be considered when interpreting DWI studies. This review article will review the various techniques of DWI acquisition and utility of qualitative as well as quantitative methods of image interpretation, with emphasis on optimal methods for ADC measurement. The current clinical applications for DWI are primarily related to oncologic evaluation: For the assessment of de novo soft tissue masses, ADC mapping can serve as a useful adjunct technique to routine anatomic sequences for lesion characterization as cyst or solid and, if solid, benign or malignant. For treated soft tissue masses, the role of DWI/ADC mapping in the assessment of treatment response as well as recurrent or residual neoplasm in the setting of operative management is discussed, especially when intravenous contrast medium cannot be given. Emerging DWI applications for non-neoplastic clinical indications are also reviewed. (orig.)

  18. Diffusion weighted imaging demystified. The technique and potential clinical applications for soft tissue imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ahlawat, Shivani [The Johns Hopkins Medical Institutions, The Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States); Fayad, Laura M. [The Johns Hopkins Medical Institutions, The Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States); The Johns Hopkins Medical Institutions, Department of Oncology, Baltimore, MD (United States); The Johns Hopkins Medical Institutions, Department of Orthopaedic Surgery, Baltimore, MD (United States)

    2018-03-15

    Diffusion-weighted imaging (DWI) is a fast, non-contrast technique that is readily available and easy to integrate into an existing imaging protocol. DWI with apparent diffusion coefficient (ADC) mapping offers a quantitative metric for soft tissue evaluation and provides information regarding the cellularity of a region of interest. There are several available methods of performing DWI, and artifacts and pitfalls must be considered when interpreting DWI studies. This review article will review the various techniques of DWI acquisition and utility of qualitative as well as quantitative methods of image interpretation, with emphasis on optimal methods for ADC measurement. The current clinical applications for DWI are primarily related to oncologic evaluation: For the assessment of de novo soft tissue masses, ADC mapping can serve as a useful adjunct technique to routine anatomic sequences for lesion characterization as cyst or solid and, if solid, benign or malignant. For treated soft tissue masses, the role of DWI/ADC mapping in the assessment of treatment response as well as recurrent or residual neoplasm in the setting of operative management is discussed, especially when intravenous contrast medium cannot be given. Emerging DWI applications for non-neoplastic clinical indications are also reviewed. (orig.)

  19. Mycobacterium avium subsp. Paratuberculosis (MAP) as a modifying factor in Crohn's disease.

    LENUS (Irish Health Repository)

    Sibartie, Shomik

    2010-02-01

    Crohn\\'s disease (CD) is a multifactorial syndrome with genetic and environmental contributions. Mycobacterium avium subspecies paratuberculosis (MAP) has been frequently isolated from mucosal tissues of patients with CD but the cellular immune response to this bacterium has been poorly described. Our aim was to examine the influence of MAP on T-cell proliferation and cytokine responses in patients with inflammatory bowel disease (IBD).

  20. Can MRI diffusion-weighted imaging identify postoperative residual/recurrent soft-tissue sarcomas?

    Directory of Open Access Journals (Sweden)

    Mai Maher ElDaly

    2018-01-01

    Full Text Available Purpose: The aim of this study was to evaluate contrast-enhanced magnetic resonance imaging (CE-MRI and quantitative diffusion-weighted imaging (DWI with apparent diffusion coefficient (ADC mapping in the detection of recurrent/residual postoperative soft tissue sarcomas. Materials and Methods: This study included 36 patients; 27 patients had postoperative recurrent/residual soft tissue sarcomas and 9 patients had postoperative and treatment-related changes (inflammation/fibrosis. The DWI was obtained with 3 b values including 0, 400, and 800 s/mm2. Calculation of the ADC value of the lesion was done via placing the region of interest (ROI to include the largest area of the lesion. ADC values were compared to histopathology. Results: Our results showed that including CE-MRI improved the diagnostic accuracy and sensitivity in recurrence detection compared to conventional non-enhanced sequences. However, it showed low specificity (55.56% with a high false-positive rate that may lead to an unnecessary biopsy of a mass such as region of postoperative scar tissue. Conclusion: The joint use of gadolinium-enhanced MRI and quantitative DWI with ADC mapping offer added value in the detection of recurrent/residual postoperative soft tissue sarcoma. This combined use increased both the diagnostic sensitivity and specificity with a cut-off average ADC value for detecting nonmyxoid recurrent/residual lesions ≤1.3 × 10−3 mm2/s (100% specificity and 90.48% sensitivity. Our results showed limited value of DWI with ADC mapping in assessing myxoid sarcomatous tumor recurrences.

  1. Strategies to improve phase-stability of ultrafast swept source optical coherence tomography for single shot imaging of transient mechanical waves at 16 kHz frame rate

    Energy Technology Data Exchange (ETDEWEB)

    Song, Shaozhen; Wei, Wei; Hsieh, Bao-Yu; Pelivanov, Ivan; O' Donnell, Matthew [Department of Bioengineering, University of Washington, Seattle, Washington 98195 (United States); Shen, Tueng T.; Wang, Ruikang K., E-mail: wangrk@uw.edu [Department of Bioengineering, University of Washington, Seattle, Washington 98195 (United States); Department of Ophthalmology, University of Washington, Seattle, Washington 98104 (United States)

    2016-05-09

    We present single-shot phase-sensitive imaging of propagating mechanical waves within tissue, enabled by an ultrafast optical coherence tomography (OCT) system powered by a 1.628 MHz Fourier domain mode-locked (FDML) swept laser source. We propose a practical strategy for phase-sensitive measurement by comparing the phases between adjacent OCT B-scans, where the B-scan contains a number of A-scans equaling an integer number of FDML buffers. With this approach, we show that micro-strain fields can be mapped with ∼3.0 nm sensitivity at ∼16 000 fps. The system's capabilities are demonstrated on porcine cornea by imaging mechanical wave propagation launched by a pulsed UV laser beam, promising non-contact, real-time, and high-resolution optical coherence elastography.

  2. Mapping Magnetic Susceptibility Anisotropies of White Matter in vivo in the Human Brain at 7 Tesla

    Science.gov (United States)

    Li, Xu; Vikram, Deepti S; Lim, Issel Anne L; Jones, Craig K; Farrell, Jonathan A.D.; van Zijl, Peter C. M.

    2012-01-01

    High-resolution magnetic resonance phase- or frequency- shift images acquired at high field show contrast related to magnetic susceptibility differences between tissues. Such contrast varies with the orientation of the organ in the field, but the development of quantitative susceptibility mapping (QSM) has made it possible to reproducibly image the intrinsic tissue susceptibility contrast. However, recent studies indicate that magnetic susceptibility is anisotropic in brain white matter and, as such, needs to be described by a symmetric second-rank tensor (χ¯¯). To fully determine the elements of this tensor, it would be necessary to acquire frequency data at six or more orientations. Assuming cylindrical symmetry of the susceptibility tensor in myelinated white matter fibers, we propose a simplified method to reconstruct the susceptibility tensor in terms of a mean magnetic susceptibility, MMS = (χ∥ + 2χ⊥)/3 and a magnetic susceptibility anisotropy, MSA = χ∥ − χ⊥, where χ∥ and χ⊥ are susceptibility parallel and perpendicular to the white matter fiber direction, respectively. Computer simulations show that with a practical head rotation angle of around 20°–30°, four head orientations suffice to reproducibly reconstruct the tensor with good accuracy. We tested this approach on whole brain 1×1×1 mm3 frequency data acquired from five healthy subjects at 7 T. The frequency information from phase images collected at four head orientations was combined with the fiber direction information extracted from diffusion tensor imaging (DTI) to map the white matter susceptibility tensor. The MMS and MSA were quantified for regions in several large white matter fiber structures, including the corona radiata, posterior thalamic radiation and corpus callosum. MMS ranged from −0.037 to −0.053 ppm (referenced to CSF being about zero). MSA values could be quantified without the need for a reference and ranged between 0.004 and 0.029 ppm, in line with

  3. Phase-contrast tomographic imaging using an X-ray interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Momose, A. [Hitachi Ltd, Advanced Research Lab., Saitama (Japan); Takeda, T.; Itai, Y. [Univ. of Tsukuba, Inst. of Clinical Medicine, Ibaraki (Japan); Yoneyama, A. [Hitachi Ltd, Central Resarch Lab., Tokyo (Japan); Hirano, K. [High Energy Accelerator Research Organization, Inst. of Materials Structure Science, Ibaraki (Japan)

    1998-05-01

    Apparatus for phase-contrast X-ray computed tomography using a monolithic X-ray interferometer is presented with some observational results for human breast tissues. Structures characteristic of the tissues were revealed in the phase-contrast tomograms. The procedure of image analysis consists of phase retrieval from X-ray interference patterns and tomographic image reconstruction from the retrieved phase shift. Next, feasibility of phase-contrast imaging using a two-crystal X-ray interferometer was studied aiming at in vivo observation in the future. In a preliminary study, the two-crystal X-ray interferometer was capable of generating fringes of 70% visibility using synchrotron X-rays. 35 refs.

  4. Phase-contrast tomographic imaging using an X-ray interferometer

    International Nuclear Information System (INIS)

    Momose, A.; Takeda, T.; Itai, Y.; Yoneyama, A.; Hirano, K.

    1998-01-01

    Apparatus for phase-contrast X-ray computed tomography using a monolithic X-ray interferometer is presented with some observational results for human breast tissues. Structures characteristic of the tissues were revealed in the phase-contrast tomograms. The procedure of image analysis consists of phase retrieval from X-ray interference patterns and tomographic image reconstruction from the retrieved phase shift. Next, feasibility of phase-contrast imaging using a two-crystal X-ray interferometer was studied aiming at in vivo observation in the future. In a preliminary study, the two-crystal X-ray interferometer was capable of generating fringes of 70% visibility using synchrotron X-rays

  5. Comprehensive analysis of TEM methods for LiFePO4/FePO4 phase mapping: spectroscopic techniques (EFTEM, STEM-EELS) and STEM diffraction techniques (ACOM-TEM)

    DEFF Research Database (Denmark)

    Mu, X.; Kobler, A.; Wang, D.

    2016-01-01

    Transmission electron microscopy (TEM) has been used intensively in investigating battery materials, e.g. to obtain phase maps of partially (dis)charged (lithium) iron phosphate (LFP/FP), which is one of the most promising cathode material for next generation lithium ion (Li-ion) batteries. Due t...

  6. Improved Culture Medium (TiKa) for Mycobacterium avium Subspecies Paratuberculosis (MAP) Matches qPCR Sensitivity and Reveals Significant Proportions of Non-viable MAP in Lymphoid Tissue of Vaccinated MAP Challenged Animals

    DEFF Research Database (Denmark)

    Bull, Tim J.; Munshil, Tulika; Melvang, Heidi Mikkelsen

    2017-01-01

    The quantitative detection of viable pathogen load is an important tool in determining the degree of infection in animals and contamination of foodstuffs. Current conventional culture methods are limited in their ability to determine these levels in Mycobacterium avium subspecies paratuberculosis......Ka culture equates well with qPCR and provides important evidence that accuracy in estimating viable MAP load using DNA tests alone may vary significantly between samples of mucosal and lymphatic origin....... (MAP) due to slow growth, clumping and low recoverability issues. The principle goal of this study was to evaluate a novel culturing process (TiKa) with unique ability to stimulate MAP growth from low sample loads and dilutions. We demonstrate it was able to stimulate a mean 29-fold increase...

  7. Benchtop phase-contrast X-ray imaging

    Energy Technology Data Exchange (ETDEWEB)

    Gundogdu, O. [Department of Physics, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)], E-mail: o.gundogdu@surrey.ac.uk; Nirgianaki, E.; Che Ismail, E.; Jenneson, P.M.; Bradley, D.A. [Department of Physics, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)

    2007-12-15

    Clinical radiography has traditionally been based on contrast obtained from absorption when X-rays pass through the body. The contrast obtained from traditional radiography can be rather poor, particularly when it comes to soft tissue. A wide range of media of interest in materials science, biology and medicine exhibit very weak absorption contrast, but they nevertheless produce significant phase shifts with X-rays. The use of phase information for imaging purposes is therefore an attractive prospect. Some of the X-ray phase-contrast imaging methods require highly monochromatic plane wave radiation and sophisticated X-ray optics. However, the propagation-based phase-contrast imaging method adapted in this paper is a relatively simple method to implement, essentially requiring only a microfocal X-ray tube and electronic detection. In this paper, we present imaging results obtained from two different benchtop X-ray sources employing the free space propagation method. X-ray phase-contrast imaging provides higher contrast in many samples, including biological tissues that have negligible absorption contrast.

  8. Determination of the Elasticity of Breast Tissue during the Menstrual Cycle Using Real-Time Shear Wave Elastography.

    Science.gov (United States)

    Li, Xiang; Wang, Jian-Nan; Fan, Zhi-Ying; Kang, Shu; Liu, Yan-Jun; Zhang, Yi-Xia; Wang, Xue-Mei

    2015-12-01

    We examined breast tissue elasticity during the menstrual cycle using real-time shear wave elastography (RT-SWE), a recent technique developed for soft tissue imaging. Written informed consent for RT-SWE was obtained from all eligible patients, who were healthy women aged between 19 and 52 y. Young's moduli of the breast tissue in the early follicular, late phase and luteal phase were compared. There were no significant differences in the mean, maximum and minimum elasticity values (Emean, Emax and Emin) and standard deviation (ESD). RT-SWE of glandular tissue revealed that ESD was increased in the early follicular phase compared with the luteal phase. Means ± SD of Emin, Emax and Emean in glandular tissue were 5.174 ± 2.138, 8.308 ± 3.166 and 6.593 ± 2.510, respectively, and in adipose tissue, 3.589 ± 2.083, 6.733 ± 3.522 and 4.857 ± 2.564, respectively. There were no significant differences in stiffness between glandular and adipose tissues throughout the menstrual cycle, but glandular tissue stiffness was lower in the luteal phase than in the early follicular phase. On the basis of these observations in normal healthy women, we believe we have obtained sufficient information to establish the baseline changes in human breast elasticity during the menstrual cycle. In the future, we intend to compare the elasticity values of healthy breast tissue with those of breast tissue affected by various pathologies. Our results reveal the significant potential of RT-SWE in the rapid and non-invasive clinical diagnosis of breast diseases, such as breast cancers. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  9. The mirror map for invertible LG models

    OpenAIRE

    Kreuzer, M

    1994-01-01

    Calculating the (a,c) ring of the maximal phase orbifold for `invertible' Landau--Ginzburg models, we show that the Berglund--H"ubsch construction works for all potentials of the relevant type. The map that sends a monomial in the original model to a twisted state in the orbifold representation of the mirror is constructed explicitly. Via this map, the OP selection rules of the chiral ring exactly correspond to the twist selection rules for the orbifold. This shows that we indeed arrive at th...

  10. A rapid, solid phase extraction (SPE technique for the extraction and gas chromatographic determination lindane pesticide residue in tissue and milk

    Directory of Open Access Journals (Sweden)

    Yuningsih

    2006-03-01

    Full Text Available Organochlorine pesticide contamination in feed can cause residue in animal product (tissue and milk, so its become a problem in food safety. Solid phase extraction (SPE has been carried out for determination organochlorine pesticide residues in food animal production. The technique was rapid, not costly and produce limited amount of hazardous-waste. Samples were homogenized with acetonitrile trough cartridge C18, eluted in fluorocyl column with 2% ether-petroleum or acetonitrile fortissue and milk samples respectively. The recoveries of tissue sample by addition lindane standard solution: 0.50 and 1.00 μg are 85.10 and 103.10% respectively, while that of milk with the addition of 0.50, 1.00 and 1.50 μg are 83.80, 88.69 and 91.24% respectively. Three replicates were carried out for every sample. According of validation criteria of FAO/IAEA the recovery for analysis of pesticide residues was 70-110%. Therefore, the method is applicable.

  11. Electrostatic frequency maps for amide-I mode of β-peptide: Comparison of molecular mechanics force field and DFT calculations

    Science.gov (United States)

    Cai, Kaicong; Zheng, Xuan; Du, Fenfen

    2017-08-01

    The spectroscopy of amide-I vibrations has been widely utilized for the understanding of dynamical structure of polypeptides. For the modeling of amide-I spectra, two frequency maps were built for β-peptide analogue (N-ethylpropionamide, NEPA) in a number of solvents within different schemes (molecular mechanics force field based, GM map; DFT calculation based, GD map), respectively. The electrostatic potentials on the amide unit that originated from solvents and peptide backbone were correlated to the amide-I frequency shift from gas phase to solution phase during map parameterization. GM map is easier to construct with negligible computational cost since the frequency calculations for the samples are purely based on force field, while GD map utilizes sophisticated DFT calculations on the representative solute-solvent clusters and brings insight into the electronic structures of solvated NEPA and its chemical environments. The results show that the maps' predicted amide-I frequencies present solvation environmental sensitivities and exhibit their specific characters with respect to the map protocols, and the obtained vibrational parameters are in satisfactory agreement with experimental amide-I spectra of NEPA in solution phase. Although different theoretical schemes based maps have their advantages and disadvantages, the present maps show their potentials in interpreting the amide-I spectra for β-peptides, respectively.

  12. Mapping out Map Libraries

    Directory of Open Access Journals (Sweden)

    Ferjan Ormeling

    2008-09-01

    Full Text Available Discussing the requirements for map data quality, map users and their library/archives environment, the paper focuses on the metadata the user would need for a correct and efficient interpretation of the map data. For such a correct interpretation, knowledge of the rules and guidelines according to which the topographers/cartographers work (such as the kind of data categories to be collected, and the degree to which these rules and guidelines were indeed followed are essential. This is not only valid for the old maps stored in our libraries and archives, but perhaps even more so for the new digital files as the format in which we now have to access our geospatial data. As this would be too much to ask from map librarians/curators, some sort of web 2.0 environment is sought where comments about data quality, completeness and up-to-dateness from knowledgeable map users regarding the specific maps or map series studied can be collected and tagged to scanned versions of these maps on the web. In order not to be subject to the same disadvantages as Wikipedia, where the ‘communis opinio’ rather than scholarship, seems to be decisive, some checking by map curators of this tagged map use information would still be needed. Cooperation between map curators and the International Cartographic Association ( ICA map and spatial data use commission to this end is suggested.

  13. Adaptive DSPI phase denoising using mutual information and 2D variational mode decomposition

    Science.gov (United States)

    Xiao, Qiyang; Li, Jian; Wu, Sijin; Li, Weixian; Yang, Lianxiang; Dong, Mingli; Zeng, Zhoumo

    2018-04-01

    In digital speckle pattern interferometry (DSPI), noise interference leads to a low peak signal-to-noise ratio (PSNR) and measurement errors in the phase map. This paper proposes an adaptive DSPI phase denoising method based on two-dimensional variational mode decomposition (2D-VMD) and mutual information. Firstly, the DSPI phase map is subjected to 2D-VMD in order to obtain a series of band-limited intrinsic mode functions (BLIMFs). Then, on the basis of characteristics of the BLIMFs and in combination with mutual information, a self-adaptive denoising method is proposed to obtain noise-free components containing the primary phase information. The noise-free components are reconstructed to obtain the denoising DSPI phase map. Simulation and experimental results show that the proposed method can effectively reduce noise interference, giving a PSNR that is higher than that of two-dimensional empirical mode decomposition methods.

  14. Numerical simulation of time fractional dual-phase-lag model of heat transfer within skin tissue during thermal therapy.

    Science.gov (United States)

    Kumar, Dinesh; Rai, K N

    2017-07-01

    In this paper, we investigated the thermal behavior in living biological tissues using time fractional dual-phase-lag bioheat transfer (DPLBHT) model subjected to Dirichelt boundary condition in presence of metabolic and electromagnetic heat sources during thermal therapy. We solved this bioheat transfer model using finite element Legendre wavelet Galerkin method (FELWGM) with help of block pulse function in sense of Caputo fractional order derivative. We compared the obtained results from FELWGM and exact method in a specific case, and found a high accuracy. Results are interpreted in the form of standard and anomalous cases for taking different order of time fractional DPLBHT model. The time to achieve hyperthermia position is discussed in both cases as standard and time fractional order derivative. The success of thermal therapy in the treatment of metastatic cancerous cell depends on time fractional order derivative to precise prediction and control of temperature. The effect of variability of parameters such as time fractional derivative, lagging times, blood perfusion coefficient, metabolic heat source and transmitted power on dimensionless temperature distribution in skin tissue is discussed in detail. The physiological parameters has been estimated, corresponding to the value of fractional order derivative for hyperthermia treatment therapy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Phase multistability of self-modulated oscillations

    DEFF Research Database (Denmark)

    Sosnovtseva, Olga; Postnov, D.E.; Nekrasov, A.M.

    2002-01-01

    The paper examines the type of multistability that one can observe in the synchronization of two oscillators when the systems individually display self-modulation or other types of multicrest wave forms. The investigation is based on a phase reduction method and on the calculation of phase maps...... nonlinearity and a biologically motivated model of nephron autoregulation are presented....

  16. Epitope mapping of the U1 small nuclear ribonucleoprotein particle in patients with systemic lupus erythematosus and mixed connective tissue disease.

    Science.gov (United States)

    Somarelli, J A; Mesa, A; Rodriguez, R; Avellan, R; Martinez, L; Zang, Y J; Greidinger, E L; Herrera, R J

    2011-03-01

    Systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD) are autoimmune illnesses characterized by the presence of high titers of autoantibodies directed against a wide range of 'self ' antigens. Proteins of the U1 small nuclear ribonucleoprotein particle (U1 snRNP) are among the most immunogenic molecules in patients with SLE and MCTD. The recent release of a crystallized U1 snRNP provides a unique opportunity to evaluate the effects of tertiary and quaternary structures on autoantigenicity within the U1 snRNP. In the present study, an epitope map was created using the U1 snRNP crystal structure. A total of 15 peptides were tested in a cohort of 68 patients with SLE, 29 with MCTD and 26 healthy individuals and mapped onto the U1 snRNP structure. Antigenic sites were detected in a variety of structures and appear to include RNA binding domains, but mostly exclude regions necessary for protein-protein interactions. These data suggest that while some autoantibodies may target U1 snRNP proteins as monomers or apoptosis-induced, protease-digested fragments, others may recognize epitopes on assembled protein subcomplexes of the U1 snRNP. Although nearly all of the peptides are strong predictors of autoimmune illness, none were successful at distinguishing between SLE and MCTD. The antigenicity of some peptides significantly correlated with several clinical symptoms. This investigation implicitly highlights the complexities of autoimmune epitopes, and autoimmune illnesses in general, and demonstrates the variability of antigens in patient populations, all of which contribute to difficult clinical diagnoses.

  17. Tile-Based Two-Dimensional Phase Unwrapping for Digital Holography Using a Modular Framework.

    Directory of Open Access Journals (Sweden)

    Georgios C Antonopoulos

    Full Text Available A variety of physical and biomedical imaging techniques, such as digital holography, interferometric synthetic aperture radar (InSAR, or magnetic resonance imaging (MRI enable measurement of the phase of a physical quantity additionally to its amplitude. However, the phase can commonly only be measured modulo 2π, as a so called wrapped phase map. Phase unwrapping is the process of obtaining the underlying physical phase map from the wrapped phase. Tile-based phase unwrapping algorithms operate by first tessellating the phase map, then unwrapping individual tiles, and finally merging them to a continuous phase map. They can be implemented computationally efficiently and are robust to noise. However, they are prone to failure in the presence of phase residues or erroneous unwraps of single tiles. We tried to overcome these shortcomings by creating novel tile unwrapping and merging algorithms as well as creating a framework that allows to combine them in modular fashion. To increase the robustness of the tile unwrapping step, we implemented a model-based algorithm that makes efficient use of linear algebra to unwrap individual tiles. Furthermore, we adapted an established pixel-based unwrapping algorithm to create a quality guided tile merger. These original algorithms as well as previously existing ones were implemented in a modular phase unwrapping C++ framework. By examining different combinations of unwrapping and merging algorithms we compared our method to existing approaches. We could show that the appropriate choice of unwrapping and merging algorithms can significantly improve the unwrapped result in the presence of phase residues and noise. Beyond that, our modular framework allows for efficient design and test of new tile-based phase unwrapping algorithms. The software developed in this study is freely available.

  18. Tile-Based Two-Dimensional Phase Unwrapping for Digital Holography Using a Modular Framework.

    Science.gov (United States)

    Antonopoulos, Georgios C; Steltner, Benjamin; Heisterkamp, Alexander; Ripken, Tammo; Meyer, Heiko

    2015-01-01

    A variety of physical and biomedical imaging techniques, such as digital holography, interferometric synthetic aperture radar (InSAR), or magnetic resonance imaging (MRI) enable measurement of the phase of a physical quantity additionally to its amplitude. However, the phase can commonly only be measured modulo 2π, as a so called wrapped phase map. Phase unwrapping is the process of obtaining the underlying physical phase map from the wrapped phase. Tile-based phase unwrapping algorithms operate by first tessellating the phase map, then unwrapping individual tiles, and finally merging them to a continuous phase map. They can be implemented computationally efficiently and are robust to noise. However, they are prone to failure in the presence of phase residues or erroneous unwraps of single tiles. We tried to overcome these shortcomings by creating novel tile unwrapping and merging algorithms as well as creating a framework that allows to combine them in modular fashion. To increase the robustness of the tile unwrapping step, we implemented a model-based algorithm that makes efficient use of linear algebra to unwrap individual tiles. Furthermore, we adapted an established pixel-based unwrapping algorithm to create a quality guided tile merger. These original algorithms as well as previously existing ones were implemented in a modular phase unwrapping C++ framework. By examining different combinations of unwrapping and merging algorithms we compared our method to existing approaches. We could show that the appropriate choice of unwrapping and merging algorithms can significantly improve the unwrapped result in the presence of phase residues and noise. Beyond that, our modular framework allows for efficient design and test of new tile-based phase unwrapping algorithms. The software developed in this study is freely available.

  19. An improved Lobatto discrete variable representation by a phase optimisation and variable mapping method

    International Nuclear Information System (INIS)

    Yu, Dequan; Cong, Shu-Lin; Sun, Zhigang

    2015-01-01

    Highlights: • An optimised finite element discrete variable representation method is proposed. • The method is tested by solving one and two dimensional Schrödinger equations. • The method is quite efficient in solving the molecular Schrödinger equation. • It is very easy to generalise the method to multidimensional problems. - Abstract: The Lobatto discrete variable representation (LDVR) proposed by Manoloupolos and Wyatt (1988) has unique features but has not been generally applied in the field of chemical dynamics. Instead, it has popular application in solving atomic physics problems, in combining with the finite element method (FE-DVR), due to its inherent abilities for treating the Coulomb singularity in spherical coordinates. In this work, an efficient phase optimisation and variable mapping procedure is proposed to improve the grid efficiency of the LDVR/FE-DVR method, which makes it not only be competing with the popular DVR methods, such as the Sinc-DVR, but also keep its advantages for treating with the Coulomb singularity. The method is illustrated by calculations for one-dimensional Coulomb potential, and the vibrational states of one-dimensional Morse potential, two-dimensional Morse potential and two-dimensional Henon–Heiles potential, which prove the efficiency of the proposed scheme and promise more general applications of the LDVR/FE-DVR method

  20. An improved Lobatto discrete variable representation by a phase optimisation and variable mapping method

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Dequan [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical and Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023 (China); Cong, Shu-Lin, E-mail: shlcong@dlut.edu.cn [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Sun, Zhigang, E-mail: zsun@dicp.ac.cn [State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical and Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023 (China); Center for Advanced Chemical Physics and 2011 Frontier Center for Quantum Science and Technology, University of Science and Technology of China, 96 Jinzhai Road, Hefei 230026 (China)

    2015-09-08

    Highlights: • An optimised finite element discrete variable representation method is proposed. • The method is tested by solving one and two dimensional Schrödinger equations. • The method is quite efficient in solving the molecular Schrödinger equation. • It is very easy to generalise the method to multidimensional problems. - Abstract: The Lobatto discrete variable representation (LDVR) proposed by Manoloupolos and Wyatt (1988) has unique features but has not been generally applied in the field of chemical dynamics. Instead, it has popular application in solving atomic physics problems, in combining with the finite element method (FE-DVR), due to its inherent abilities for treating the Coulomb singularity in spherical coordinates. In this work, an efficient phase optimisation and variable mapping procedure is proposed to improve the grid efficiency of the LDVR/FE-DVR method, which makes it not only be competing with the popular DVR methods, such as the Sinc-DVR, but also keep its advantages for treating with the Coulomb singularity. The method is illustrated by calculations for one-dimensional Coulomb potential, and the vibrational states of one-dimensional Morse potential, two-dimensional Morse potential and two-dimensional Henon–Heiles potential, which prove the efficiency of the proposed scheme and promise more general applications of the LDVR/FE-DVR method.

  1. Derivation of elastic stiffness from site-matched mineral density and acoustic impedance maps

    International Nuclear Information System (INIS)

    Raum, Kay; Cleveland, Robin O; Peyrin, Francoise; Laugier, Pascal

    2006-01-01

    200 MHz acoustic impedance maps and site-matched synchrotron radiation micro computed tomography (SR-μCT) maps of tissue degree of mineralization of bone (DMB) were used to derive the elastic coefficient c 33 in cross sections of human cortical bone. To accomplish this goal, a model was developed to relate the DMB accessible with SR-μCT to mass density. The formulation incorporates the volume fractions and densities of the major bone tissue components (collagen, mineral and water), and accounts for tissue porosity. We found that the mass density can be well modelled by a second-order polynomial fit to DMB (R 2 = 0.999) and appears to be consistent with measurements of many different types of mineralized tissues. The derived elastic coefficient c 33 correlated more strongly with the acoustic impedance (R 2 = 0.996) than with mass density (R 2 = 0.310). This finding suggests that estimates of c 33 made from measurements of the acoustic impedance are more reliable than those made from density measurements. Mass density and elastic coefficient were in the range between 1.66 and 2.00 g cm -3 and 14.8 and 75.4 GPa, respectively. Although SAM inspection is limited to the evaluation of carefully prepared sample surfaces, it provides a two-dimensional quantitative estimate of elastic tissue properties at the tissue level

  2. Highlighting material structure with transmission electron diffraction correlation coefficient maps.

    Science.gov (United States)

    Kiss, Ákos K; Rauch, Edgar F; Lábár, János L

    2016-04-01

    Correlation coefficient maps are constructed by computing the differences between neighboring diffraction patterns collected in a transmission electron microscope in scanning mode. The maps are shown to highlight material structural features like grain boundaries, second phase particles or dislocations. The inclination of the inner crystal interfaces are directly deduced from the resulting contrast. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Chaotic dynamics in two-dimensional noninvertible maps

    CERN Document Server

    Mira, Christian; Cathala, Jean-Claude; Gardini, Laura

    1996-01-01

    This book is essentially devoted to complex properties (Phase plane structure and bifurcations) of two-dimensional noninvertible maps, i.e. maps having either a non-unique inverse, or no real inverse, according to the plane point. They constitute models of sets of discrete dynamical systems encountered in Engineering (Control, Signal Processing, Electronics), Physics, Economics, Life Sciences. Compared to the studies made in the one-dimensional case, the two-dimensional situation remained a long time in an underdeveloped state. It is only since these last years that the interest for this resea

  4. Initial studies of synchrotron radiation phase-contrast imaging in the field of medicine

    International Nuclear Information System (INIS)

    Chen Shaoliang; Zhang Xi; Peng Yifeng; Li Beilei; Cheng Aiping; Zhu Peiping; Yuan Xiqing; Huang Wanxia

    2010-01-01

    Recently,research on using X-ray phase information in medicine has been growing remarkably fast. Phase-contrast imaging with synchrotron radiation can reveal inner soft tissues such as tendons, cartilage, ligaments, adipose tissue, vessels and nerves without a contrast agent. We have visualized the liver, bile duct, lung, kidney, stomach and intestine, heart, blood vessel, bone and arthrosis, and tumor tissues using 'in-line' phase contrast imaging and diffraction-enhanced imaging. It is seen that the synchrotron radiation graphs show much higher resolution. This method is especially suitable for studying soft tissue structure and blood vessels. (authors)

  5. Identification of QTLs Associated with Callogenesis and Embryogenesis in Oil Palm Using Genetic Linkage Maps Improved with SSR Markers.

    NARCIS (Netherlands)

    Ting, N.C.; Jansen, J.; Nagappan, J.; Ishak, Z.; Chin, C.W.; Tan, S.G.; Cheah, S.C.; Singh, R.

    2013-01-01

    Clonal reproduction of oil palm by means of tissue culture is a very inefficient process. Tissue culturability is known to be genotype dependent with some genotypes being more amenable to tissue culture than others. In this study, genetic linkage maps enriched with simple sequence repeat (SSR)

  6. X-ray micro-tomography for investigations of brain tissues on cellular level

    Science.gov (United States)

    Khimchenko, Anna; Schulz, Georg; Deyhle, Hans; Thalmann, Peter; Zanette, Irene; Zdora, Marie-Christine; Bikis, Christos; Hipp, Alexander; Hieber, Simone E.; Schweighauser, Gabriel; Hench, Jürgen; Müller, Bert

    2016-10-01

    X-ray imaging in absorption contrast mode is well established for hard tissue visualization. However, performance for lower density materials is limited due to a reduced contrast. Our aim is three-dimensional (3D) characterization of micro-morphology of human brain tissues down to (sub-)cellular resolution within a laboratory environment. Using the laboratory-based microtomography (μCT) system nanotom m (GE Sensing and Inspection Technologies GmbH, Wunstorf, Germany) and synchrotron radiation at the Diamond-Manchester Imaging Branchline I13-2 (Diamond Light Source, Didcot, UK), we have acquired 3D data with a resolution down to 0.45 μm for visualization of a human cerebellum specimen down to cellular level. We have shown that all selected modalities, namely laboratory-based absorption contrast micro-tomography (LBμCT), synchrotron radiation based in-line single distance phase contrast tomography (SDPR) and synchrotron radiation based single-grating interferometry (GI), can reach cellular resolution for tissue samples with a size in the mm-range. The results are discussed qualitatively in comparison to optical microscopy of haematoxylin and eosin (HE) stained sections. As phase contrast yields to a better data quality for soft tissues and in order to overcome restrictions of limited beamline access for phase contrast measurements, we have equipped the μCT system nanotom m with a double-grating phase contrast set-up. Preliminary experimental results of a knee sample consisting of a bony part and a cartilage demonstrate that phase contrast data exhibits better quality compared to absorption contrast. Currently, the set-up is under adjustment. It is expected that cellular resolution would also be achieved. The questions arise (1) what would be the quality gain of laboratory-based phase contrast in comparison to laboratory-based absorption contrast tomography and (2) could laboratory-based phase contrast data provide comparable results to synchrotron radiation based

  7. Dynamic Quantitative T1 Mapping in Orthotopic Brain Tumor Xenografts

    Directory of Open Access Journals (Sweden)

    Kelsey Herrmann

    2016-04-01

    Full Text Available Human brain tumors such as glioblastomas are typically detected using conventional, nonquantitative magnetic resonance imaging (MRI techniques, such as T2-weighted and contrast enhanced T1-weighted MRI. In this manuscript, we tested whether dynamic quantitative T1 mapping by MRI can localize orthotopic glioma tumors in an objective manner. Quantitative T1 mapping was performed by MRI over multiple time points using the conventional contrast agent Optimark. We compared signal differences to determine the gadolinium concentration in tissues over time. The T1 parametric maps made it easy to identify the regions of contrast enhancement and thus tumor location. Doubling the typical human dose of contrast agent resulted in a clearer demarcation of these tumors. Therefore, T1 mapping of brain tumors is gadolinium dose dependent and improves detection of tumors by MRI. The use of T1 maps provides a quantitative means to evaluate tumor detection by gadolinium-based contrast agents over time. This dynamic quantitative T1 mapping technique will also enable future quantitative evaluation of various targeted MRI contrast agents.

  8. Revising scenario map for plant management via interaction of stakeholders' intentions and constraints

    International Nuclear Information System (INIS)

    Ohsawa, Yukio; Taya, Sayuri

    2013-01-01

    The purpose of this study is to put knowledge of plant safety together and make a map that will help to understand a system of plant and notice new links among components. This map, called the scenario map, can be used for aiding the chance discoveries - decision of various stakeholders of the system based on their awareness of latent dynamics underlying observed events. The trustworthiness of their analysis will be also reinforced by linking relevant data to the nodes and lines in the graph. In order to have stakeholders be aware of information missed in available data, we invented a method of workshop and moved forward with a rough map of plant safety. The first phase attempts to externalize differences in the bodies of knowledge of each participant. In the second, introducing Tsugo Roulette (TR) – the core component of this paper -, latent dynamics where physical and social causalities emerge is externalized. Then participants revise the scenario map based on their thoughts by the second phase, to finally evaluate the utility of nodes and lines in the graph. In accordance with each phase, participants in the workshop could exchange their tsugoes - views of intentions and constraints - and realize new links or nodes to be evaluated highly by experts in the corresponding domain. (author)

  9. Analysis Of Transcriptomes In A Porcine Tissue Collection Using RNA-Seq And Genome Assembly 10

    DEFF Research Database (Denmark)

    Hornshøj, Henrik; Thomsen, Bo; Hedegaard, Jakob

    2011-01-01

    The release of Sus scrofa genome assembly 10 supports improvement of the pig genome annotation and in depth transcriptome analyses using next-generation sequencing technologies. In this study we analyze RNA-seq reads from a tissue collection, including 10 separate tissues from Duroc boars and 10...... short read alignment software we mapped the reads to the genome assembly 10. We extracted contig sequences of gene transcripts using the Cufflinks software. Based on this information we identified expressed genes that are present in the genome assembly. The portion of these genes being previously known...... was roughly estimated by sequence comparison to known genes. Similarly, we searched for genes that are expressed in the tissues but not present in the genome assembly by aligning the non-genome-mapped reads to known gene transcripts. For the genes predicted to have alternative transcript variants by Cufflinks...

  10. Geologic Mapping of the Olympus Mons Volcano, Mars

    Science.gov (United States)

    Bleacher, J. E.; Williams, D. A.; Shean, D.; Greeley, R.

    2012-01-01

    We are in the third year of a three-year Mars Data Analysis Program project to map the morphology of the Olympus Mons volcano, Mars, using ArcGIS by ESRI. The final product of this project is to be a 1:1,000,000-scale geologic map. The scientific questions upon which this mapping project is based include understanding the volcanic development and modification by structural, aeolian, and possibly glacial processes. The project s scientific objectives are based upon preliminary mapping by Bleacher et al. [1] along a approx.80-km-wide north-south swath of the volcano corresponding to High Resolution Stereo Camera (HRSC) image h0037. The preliminary project, which covered approx.20% of the volcano s surface, resulted in several significant findings, including: 1) channel-fed lava flow surfaces are areally more abundant than tube-fed surfaces by a ratio of 5:1, 2) channel-fed flows consistently embay tube-fed flows, 3) lava fans appear to be linked to tube-fed flows, 4) no volcanic vents were identified within the map region, and 5) a Hummocky unit surrounds the summit and is likely a combination of non-channelized flows, dust, ash, and/or frozen volatiles. These results led to the suggestion that the volcano had experienced a transition from long-lived tube-forming eruptions to more sporadic and shorter-lived, channel-forming eruptions, as seen at Hawaiian volcanoes between the tholeiitic shield building phase (Kilauea to Mauna Loa) and alkalic capping phase (Hualalai and Mauna Kea).

  11. 3D on-chip microscopy of optically cleared tissue

    Science.gov (United States)

    Zhang, Yibo; Shin, Yoonjung; Sung, Kevin; Yang, Sam; Chen, Harrison; Wang, Hongda; Teng, Da; Rivenson, Yair; Kulkarni, Rajan P.; Ozcan, Aydogan

    2018-02-01

    Traditional pathology relies on tissue biopsy, micro-sectioning, immunohistochemistry and microscopic imaging, which are relatively expensive and labor-intensive, and therefore are less accessible in resource-limited areas. Low-cost tissue clearing techniques, such as the simplified CLARITY method (SCM), are promising to potentially reduce the cost of disease diagnosis by providing 3D imaging and phenotyping of thicker tissue samples with simpler preparation steps. However, the mainstream imaging approach for cleared tissue, fluorescence microscopy, suffers from high-cost, photobleaching and signal fading. As an alternative approach to fluorescence, here we demonstrate 3D imaging of SCMcleared tissue using on-chip holography, which is based on pixel-super-resolution and multi-height phase recovery algorithms to digitally compute the sample's amplitude and phase images at various z-slices/depths through the sample. The tissue clearing procedures and the lens-free imaging system were jointly optimized to find the best illumination wavelength, tissue thickness, staining solution pH, and the number of hologram heights to maximize the imaged tissue volume, minimize the amount of acquired data, while maintaining a high contrast-to-noise ratio for the imaged cells. After this optimization, we achieved 3D imaging of a 200-μm thick cleared mouse brain tissue over a field-of-view of based microscope (20× 0.75NA). Moreover, the lens-free microscope achieves an order-of-magnitude better data efficiency compared to its lens-based counterparts for volumetric imaging of samples. The presented low-cost and high-throughput lens-free tissue imaging technique enabled by CLARITY can be used in various biomedical applications in low-resource-settings.

  12. Calculation of solidification microstructure maps for the system Al-Fe-Si

    International Nuclear Information System (INIS)

    Gilgien, P.

    1996-01-01

    Computer programs have been developed in order to calculate solidification microstructure maps for binary and ternary alloys. These programs are based on recent analytical models for the constrained growth of dendrites and eutectics. Due to the importance of phase diagrams data, programs for the calculation of growth kinetics are coupled with ThermoCalc, a commercial software for phase diagram calculations. These programs have been used to calculate a solidification microstructure map for the Al-Fe system from 0 to 4 at%Fe. Comparison of the calculated results with an experimental solidification microstructure map from the literature shows that all microstructure transitions were predicted. Nevertheless there remain significant discrepancies between some calculated and experimental transition velocities. The programs were also used to calculate solidification microstructure maps in the Al-rich corner of the Al-Fe-Si system (0 to 8 at% Fe and 0 to 8 at% Si). In this case also, calculated results were in satisfactory agreement with experimental solidification microstructure maps, although the comparison was only partial since experimental ternary microstructure maps are less complete than for the binary system, and because the available thermodynamic database does not, as yet, include metastable phases. Laser surface remelting experiments were carried out on an Al-4 at% Fe alloy in order to link results from the literature, obtained at high solidification rates by laser surface remelting and at low solidification rates by Bridman experiments. Finally, Bridman experiments were carried out with an Al-2.63 wt% Fe alloy in order to determine the critical velocity at which a planar Al-Al 13 Fe 4 eutectic front is destabilised in a cellular eutectic by a small amount of Si. The critical solidification velocity thus obtained was in agreement with a criterion of constitutional undercooling. (author) figs., tabs., refs

  13. Quantum mechanics in phase space

    DEFF Research Database (Denmark)

    Hansen, Frank

    1984-01-01

    A reformulation of quantum mechanics for a finite system is given using twisted multiplication of functions on phase space and Tomita's theory of generalized Hilbert algebras. Quantization of a classical observable h is achieved when the twisted exponential Exp0(-h) is defined as a tempered....... Generalized Weyl-Wigner maps related to the notion of Hamiltonian weight are studied and used in the formulation of a twisted spectral theory for functions on phase space. Some inequalities for Wigner functions on phase space are proven. A brief discussion of the classical limit obtained through dilations...

  14. Improved method for drawing of a glycan map, and the first page of glycan atlas, which is a compilation of glycan maps for a whole organism.

    Directory of Open Access Journals (Sweden)

    Shunji Natsuka

    Full Text Available Glycan Atlas is a set of glycan maps over the whole body of an organism. The glycan map that includes data of glycan structure and quantity displays micro-heterogeneity of the glycans in a tissue, an organ, or cells. The two-dimensional glycan mapping is widely used for structure analysis of N-linked oligosaccharides on glycoproteins. In this study we developed a comprehensive method for the mapping of both N- and O-glycans with and without sialic acid. The mapping data of 150 standard pyridylaminated glycans were collected. The empirical additivity rule which was proposed in former reports was able to adapt for this extended glycan map. The adapted rule is that the elution time of pyridylamino glycans on high performance liquid chromatography (HPLC is expected to be the simple sum of the partial elution times assigned to each monosaccharide residue. The comprehensive mapping method developed in this study is a powerful tool for describing the micro-heterogeneity of the glycans. Furthermore, we prepared 42 pyridylamino (PA- glycans from human serum and were able to draw the map of human serum N- and O-glycans as an initial step of Glycan Atlas editing.

  15. Molecular imaging of cannabis leaf tissue with MeV-SIMS method

    Science.gov (United States)

    Jenčič, Boštjan; Jeromel, Luka; Ogrinc Potočnik, Nina; Vogel-Mikuš, Katarina; Kovačec, Eva; Regvar, Marjana; Siketić, Zdravko; Vavpetič, Primož; Rupnik, Zdravko; Bučar, Klemen; Kelemen, Mitja; Kovač, Janez; Pelicon, Primož

    2016-03-01

    To broaden our analytical capabilities with molecular imaging in addition to the existing elemental imaging with micro-PIXE, a linear Time-Of-Flight mass spectrometer for MeV Secondary Ion Mass Spectrometry (MeV-SIMS) was constructed and added to the existing nuclear microprobe at the Jožef Stefan Institute. We measured absolute molecular yields and damage cross-section of reference materials, without significant alteration of the fragile biological samples during the duration of measurements in the mapping mode. We explored the analytical capability of the MeV-SIMS technique for chemical mapping of the plant tissue of medicinal cannabis leaves. A series of hand-cut plant tissue slices were prepared by standard shock-freezing and freeze-drying protocol and deposited on the Si wafer. We show the measured MeV-SIMS spectra showing a series of peaks in the mass area of cannabinoids, as well as their corresponding maps. The indicated molecular distributions at masses of 345.5 u and 359.4 u may be attributed to the protonated THCA and THCA-C4 acids, and show enhancement in the areas with opened trichome morphology.

  16. Molecular imaging of cannabis leaf tissue with MeV-SIMS method

    Energy Technology Data Exchange (ETDEWEB)

    Jenčič, Boštjan, E-mail: bostjan.jencic@ijs.si [Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Jeromel, Luka [Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Ogrinc Potočnik, Nina [Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); M4I, Maastricht University, Peter Debijelaan 25A, 6229 HX Maastricht (Netherlands); Vogel-Mikuš, Katarina [Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); University of Ljubljana, Biotechnical Faculty, Dept. of Biology, Večna pot 11, SI-1000 Ljubljana (Slovenia); Kovačec, Eva; Regvar, Marjana [University of Ljubljana, Biotechnical Faculty, Dept. of Biology, Večna pot 11, SI-1000 Ljubljana (Slovenia); Siketić, Zdravko [Ruđer Bošković Institute, P.O. Box 180, 10000 Zagreb (Croatia); Vavpetič, Primož; Rupnik, Zdravko; Bučar, Klemen; Kelemen, Mitja; Kovač, Janez; Pelicon, Primož [Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia)

    2016-03-15

    To broaden our analytical capabilities with molecular imaging in addition to the existing elemental imaging with micro-PIXE, a linear Time-Of-Flight mass spectrometer for MeV Secondary Ion Mass Spectrometry (MeV-SIMS) was constructed and added to the existing nuclear microprobe at the Jožef Stefan Institute. We measured absolute molecular yields and damage cross-section of reference materials, without significant alteration of the fragile biological samples during the duration of measurements in the mapping mode. We explored the analytical capability of the MeV-SIMS technique for chemical mapping of the plant tissue of medicinal cannabis leaves. A series of hand-cut plant tissue slices were prepared by standard shock-freezing and freeze-drying protocol and deposited on the Si wafer. We show the measured MeV-SIMS spectra showing a series of peaks in the mass area of cannabinoids, as well as their corresponding maps. The indicated molecular distributions at masses of 345.5 u and 359.4 u may be attributed to the protonated THCA and THCA-C4 acids, and show enhancement in the areas with opened trichome morphology.

  17. Molecular imaging of cannabis leaf tissue with MeV-SIMS method

    International Nuclear Information System (INIS)

    Jenčič, Boštjan; Jeromel, Luka; Ogrinc Potočnik, Nina; Vogel-Mikuš, Katarina; Kovačec, Eva; Regvar, Marjana; Siketić, Zdravko; Vavpetič, Primož; Rupnik, Zdravko; Bučar, Klemen; Kelemen, Mitja; Kovač, Janez; Pelicon, Primož

    2016-01-01

    To broaden our analytical capabilities with molecular imaging in addition to the existing elemental imaging with micro-PIXE, a linear Time-Of-Flight mass spectrometer for MeV Secondary Ion Mass Spectrometry (MeV-SIMS) was constructed and added to the existing nuclear microprobe at the Jožef Stefan Institute. We measured absolute molecular yields and damage cross-section of reference materials, without significant alteration of the fragile biological samples during the duration of measurements in the mapping mode. We explored the analytical capability of the MeV-SIMS technique for chemical mapping of the plant tissue of medicinal cannabis leaves. A series of hand-cut plant tissue slices were prepared by standard shock-freezing and freeze-drying protocol and deposited on the Si wafer. We show the measured MeV-SIMS spectra showing a series of peaks in the mass area of cannabinoids, as well as their corresponding maps. The indicated molecular distributions at masses of 345.5 u and 359.4 u may be attributed to the protonated THCA and THCA-C4 acids, and show enhancement in the areas with opened trichome morphology.

  18. Mapping and uncertainty analysis of energy and pitch angle phase space in the DIII-D fast ion loss detector

    Energy Technology Data Exchange (ETDEWEB)

    Pace, D. C., E-mail: pacedc@fusion.gat.com; Fisher, R. K.; Van Zeeland, M. A. [General Atomics, PO Box 85608, San Diego, California 92186-5608 (United States); Pipes, R. [Department of Physics, University of Hawaii, Hilo, Hawaii 96720-4091 (United States)

    2014-11-15

    New phase space mapping and uncertainty analysis of energetic ion loss data in the DIII-D tokamak provides experimental results that serve as valuable constraints in first-principles simulations of energetic ion transport. Beam ion losses are measured by the fast ion loss detector (FILD) diagnostic system consisting of two magnetic spectrometers placed independently along the outer wall. Monte Carlo simulations of mono-energetic and single-pitch ions reaching the FILDs are used to determine the expected uncertainty in the measurements. Modeling shows that the variation in gyrophase of 80 keV beam ions at the FILD aperture can produce an apparent measured energy signature spanning across 50-140 keV. These calculations compare favorably with experiments in which neutral beam prompt loss provides a well known energy and pitch distribution.

  19. Mapping and uncertainty analysis of energy and pitch angle phase space in the DIII-D fast ion loss detector.

    Science.gov (United States)

    Pace, D C; Pipes, R; Fisher, R K; Van Zeeland, M A

    2014-11-01

    New phase space mapping and uncertainty analysis of energetic ion loss data in the DIII-D tokamak provides experimental results that serve as valuable constraints in first-principles simulations of energetic ion transport. Beam ion losses are measured by the fast ion loss detector (FILD) diagnostic system consisting of two magnetic spectrometers placed independently along the outer wall. Monte Carlo simulations of mono-energetic and single-pitch ions reaching the FILDs are used to determine the expected uncertainty in the measurements. Modeling shows that the variation in gyrophase of 80 keV beam ions at the FILD aperture can produce an apparent measured energy signature spanning across 50-140 keV. These calculations compare favorably with experiments in which neutral beam prompt loss provides a well known energy and pitch distribution.

  20. Cryptanalysis and improvement of an optical image encryption scheme using a chaotic Baker map and double random phase encoding

    International Nuclear Information System (INIS)

    Chen, Jun-Xin; Fu, Chong; Zhu, Zhi-Liang; Zhang, Li-Bo; Zhang, Yushu

    2014-01-01

    In this paper, we evaluate the security of an enhanced double random phase encoding (DRPE) image encryption scheme (2013 J. Lightwave Technol. 31 2533). The original system employs a chaotic Baker map prior to DRPE to provide more protection to the plain image and hence promote the security level of DRPE, as claimed. However, cryptanalysis shows that this scheme is vulnerable to a chosen-plaintext attack, and the ciphertext can be precisely recovered. The corresponding improvement is subsequently reported upon the basic premise that no extra equipment or computational complexity is required. The simulation results and security analyses prove its effectiveness and security. The proposed achievements are suitable for all cryptosystems under permutation and, following that, the DRPE architecture, and we hope that our work can motivate the further research on optical image encryption. (paper)

  1. Cryptanalysis and improvement of an optical image encryption scheme using a chaotic Baker map and double random phase encoding

    Science.gov (United States)

    Chen, Jun-Xin; Zhu, Zhi-Liang; Fu, Chong; Zhang, Li-Bo; Zhang, Yushu

    2014-12-01

    In this paper, we evaluate the security of an enhanced double random phase encoding (DRPE) image encryption scheme (2013 J. Lightwave Technol. 31 2533). The original system employs a chaotic Baker map prior to DRPE to provide more protection to the plain image and hence promote the security level of DRPE, as claimed. However, cryptanalysis shows that this scheme is vulnerable to a chosen-plaintext attack, and the ciphertext can be precisely recovered. The corresponding improvement is subsequently reported upon the basic premise that no extra equipment or computational complexity is required. The simulation results and security analyses prove its effectiveness and security. The proposed achievements are suitable for all cryptosystems under permutation and, following that, the DRPE architecture, and we hope that our work can motivate the further research on optical image encryption.

  2. Highlighting material structure with transmission electron diffraction correlation coefficient maps

    International Nuclear Information System (INIS)

    Kiss, Ákos K.; Rauch, Edgar F.; Lábár, János L.

    2016-01-01

    Correlation coefficient maps are constructed by computing the differences between neighboring diffraction patterns collected in a transmission electron microscope in scanning mode. The maps are shown to highlight material structural features like grain boundaries, second phase particles or dislocations. The inclination of the inner crystal interfaces are directly deduced from the resulting contrast. - Highlights: • We propose a novel technique to image the structure of polycrystalline TEM-samples. • Correlation coefficients maps highlights the evolution of the diffracting signal. • 3D views of grain boundaries are provided for nano-particles or polycrystals.

  3. Heterogeneity mapping of protein expression in tumors using quantitative immunofluorescence.

    Science.gov (United States)

    Faratian, Dana; Christiansen, Jason; Gustavson, Mark; Jones, Christine; Scott, Christopher; Um, InHwa; Harrison, David J

    2011-10-25

    Morphologic heterogeneity within an individual tumor is well-recognized by histopathologists in surgical practice. While this often takes the form of areas of distinct differentiation into recognized histological subtypes, or different pathological grade, often there are more subtle differences in phenotype which defy accurate classification (Figure 1). Ultimately, since morphology is dictated by the underlying molecular phenotype, areas with visible differences are likely to be accompanied by differences in the expression of proteins which orchestrate cellular function and behavior, and therefore, appearance. The significance of visible and invisible (molecular) heterogeneity for prognosis is unknown, but recent evidence suggests that, at least at the genetic level, heterogeneity exists in the primary tumor(1,2), and some of these sub-clones give rise to metastatic (and therefore lethal) disease. Moreover, some proteins are measured as biomarkers because they are the targets of therapy (for instance ER and HER2 for tamoxifen and trastuzumab (Herceptin), respectively). If these proteins show variable expression within a tumor then therapeutic responses may also be variable. The widely used histopathologic scoring schemes for immunohistochemistry either ignore, or numerically homogenize the quantification of protein expression. Similarly, in destructive techniques, where the tumor samples are homogenized (such as gene expression profiling), quantitative information can be elucidated, but spatial information is lost. Genetic heterogeneity mapping approaches in pancreatic cancer have relied either on generation of a single cell suspension(3), or on macrodissection(4). A recent study has used quantum dots in order to map morphologic and molecular heterogeneity in prostate cancer tissue(5), providing proof of principle that morphology and molecular mapping is feasible, but falling short of quantifying the heterogeneity. Since immunohistochemistry is, at best, only semi

  4. The porcine acute phase response to infection with Actinobacillus pleuropneumoniae. Haptoglobin, C-reactive protein, major acute phase protein and serum amyloid a protein are sensitive indicators of infection

    DEFF Research Database (Denmark)

    Heegaard, Peter M. H.; Klausen, Joan; Nielsen, J.P.

    1998-01-01

    response peaking at around 2 days after infection. Haptoglobin, C-reactive protein (CRP), and major acute phase protein (MAP) responded with large increases in serum levels, preceding the development of specific antibodies by 4-5 days. Serum amyloid A protein (SAA) was also strongly induced. The increase......, kinetics of induction and normalization were different between these proteins. It is concluded that experimental Ap-infection by the aerosol route induces a typical acute phase reaction in the pig, and that pig Hp, CRP, MAP, and SAA are major acute phase reactants. These findings indicate the possibility...

  5. Dynamic mapping of conical intersection seams: A general method for incorporating the geometric phase in adiabatic dynamics in polyatomic systems.

    Science.gov (United States)

    Xie, Changjian; Malbon, Christopher L; Yarkony, David R; Guo, Hua

    2017-07-28

    The incorporation of the geometric phase in single-state adiabatic dynamics near a conical intersection (CI) seam has so far been restricted to molecular systems with high symmetry or simple model Hamiltonians. This is due to the fact that the ab initio determined derivative coupling (DC) in a multi-dimensional space is not curl-free, thus making its line integral path dependent. In a recent work [C. L. Malbon et al., J. Chem. Phys. 145, 234111 (2016)], we proposed a new and general approach based on an ab initio determined diabatic representation consisting of only two electronic states, in which the DC is completely removable, so that its line integral is path independent in the simply connected domains that exclude the CI seam. Then with the CIs included, the line integral of the single-valued DC can be used to construct the complex geometry-dependent phase needed to exactly eliminate the double-valued character of the real-valued adiabatic electronic wavefunction. This geometry-dependent phase gives rise to a vector potential which, when included in the adiabatic representation, rigorously accounts for the geometric phase in a system with an arbitrary locus of the CI seam and an arbitrary number of internal coordinates. In this work, we demonstrate this approach in a three-dimensional treatment of the tunneling facilitated dissociation of the S 1 state of phenol, which is affected by a C s symmetry allowed but otherwise accidental seam of CI. Here, since the space is three-dimensional rather than two-dimensional, the seam is a curve rather than a point. The nodal structure of the ground state vibronic wavefunction is shown to map out the seam of CI.

  6. Map-based cloning and expression analysis of BMR-6 in sorghum

    Indian Academy of Sciences (India)

    CAD), using a map-based cloning approach. Genetic complementation confirmed that CAD is responsible for the BMR-6 phenotype. BMR-6 gene was expressed in all tested sorghum tissues, with the highest being in midrib and stem. Transient ...

  7. Assessment of tissue viability by polarization spectroscopy

    Science.gov (United States)

    Nilsson, G.; Anderson, C.; Henricson, J.; Leahy, M.; O'Doherty, J.; Sjöberg, F.

    2008-09-01

    A new and versatile method for tissue viability imaging based on polarization spectroscopy of blood in superficial tissue structures such as the skin is presented in this paper. Linearly polarized light in the visible wavelength region is partly reflected directly by the skin surface and partly diffusely backscattered from the dermal tissue matrix. Most of the directly reflected light preserves its polarization state while the light returning from the deeper tissue layers is depolarized. By the use of a polarization filter positioned in front of a sensitive CCD-array, the light directly reflected from the tissue surface is blocked, while the depolarized light returning from the deeper tissue layers reaches the detector array. By separating the colour planes of the detected image, spectroscopic information about the amount of red blood cells (RBCs) in the microvascular network of the tissue under investigation can be derived. A theory that utilizes the differences in light absorption of RBCs and bloodless tissue in the red and green wavelength region forms the basis of an algorithm for displaying a colour coded map of the RBC distribution in a tissue. Using a fluid model, a linear relationship (cc. = 0.99) between RBC concentration and the output signal was demonstrated within the physiological range 0-4%. In-vivo evaluation using transepidermal application of acetylcholine by the way of iontophoresis displayed the heterogeneity pattern of the vasodilatation produced by the vasoactive agent. Applications of this novel technology are likely to be found in drug and skin care product development as well as in the assessment of skin irritation and tissue repair processes and even ultimately in a clinic case situation.

  8. Genetic Map of Mango: A Tool for Mango Breeding

    Directory of Open Access Journals (Sweden)

    David N. Kuhn

    2017-04-01

    Full Text Available Mango (Mangifera indica is an economically and nutritionally important tropical/subtropical tree fruit crop. Most of the current commercial cultivars are selections rather than the products of breeding programs. To improve the efficiency of mango breeding, molecular markers have been used to create a consensus genetic map that identifies all 20 linkage groups in seven mapping populations. Polyembryony is an important mango trait, used for clonal propagation of cultivars and rootstocks. In polyembryonic mango cultivars, in addition to a zygotic embryo, several apomictic embryos develop from maternal tissue surrounding the fertilized egg cell. This trait has been associated with linkage group 8 in our consensus genetic map and has been validated in two of the seven mapping populations. In addition, we have observed a significant association between trait and single nucleotide polymorphism (SNP markers for the vegetative trait of branch habit and the fruit traits of bloom, ground skin color, blush intensity, beak shape, and pulp color.

  9. STrategically Acquired Gradient Echo (STAGE) imaging, part I: Creating enhanced T1 contrast and standardized susceptibility weighted imaging and quantitative susceptibility mapping.

    Science.gov (United States)

    Chen, Yongsheng; Liu, Saifeng; Wang, Yu; Kang, Yan; Haacke, E Mark

    2018-02-01

    To provide whole brain grey matter (GM) to white matter (WM) contrast enhanced T1W (T1WE) images, multi-echo quantitative susceptibility mapping (QSM), proton density (PD) weighted images, T1 maps, PD maps, susceptibility weighted imaging (SWI), and R2* maps with minimal misregistration in scanning times creating enhanced GM/WM contrast (the T1WE). The proposed T1WE image was created from a combination of the proton density weighted (6°, PDW) and T1W (24°) images and corrected for RF transmit field variations. Prior to the QSM calculation, a multi-echo phase unwrapping strategy was implemented using the unwrapped short echo to unwrap the longer echo to speed up computation. R2* maps were used to mask deep grey matter and veins during the iterative QSM calculation. A weighted-average sum of susceptibility maps was generated to increase the signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR). The proposed T1WE image has a significantly improved CNR both for WM to deep GM and WM to cortical GM compared to the acquired T1W image (the first echo of 24° scan) and the T1MPRAGE image. The weighted-average susceptibility maps have 80±26%, 55±22%, 108±33% SNR increases across the ten subjects compared to the single echo result of 17.5ms for the putamen, caudate nucleus, and globus pallidus, respectively. STAGE imaging offers the potential to create a standardized brain imaging protocol providing four pieces of quantitative tissue property information and multiple types of qualitative information in just 5min. Published by Elsevier Inc.

  10. Differential screening and mass mapping of proteins from premalignant and cancer cell lines using nonporous reversed-phase HPLC coupled with mass spectrometric analysis.

    Science.gov (United States)

    Chong, B E; Hamler, R L; Lubman, D M; Ethier, S P; Rosenspire, A J; Miller, F R

    2001-03-15

    Nonporous (NPS) RP-HPLC has been used to rapidly separate proteins from whole cell lysates of human breast cell lines. The nonporous separation involves the use of hard-sphere silica beads of 1.5-microm diameter coated with C18, which can be used to separate proteins ranging from 5 to 90 kDa. Using only 30-40 microg of total protein, the protein molecular weights are detectable on-line using an ESI-oaTOF MS. Of hundreds of proteins detected in this mass range, approxinately 75-80 are more highly expressed. The molecular weight profiles can be displayed as a mass map analogous to a virtual "1-D gel" and differentially expressed proteins can be compared by image analysis. The separated proteins can also be detected by UV absorption and differentially expressed proteins quantified. The eluting proteins can be collected in the liquid phase and the molecular weight and peptide maps determined by MALDI-TOF MS for identification. It is demonstrated that the expressed protein profiles change during neoplastic progression and that many oncoproteins are readily detected. It is also shown that the response of premalignant cancer cells to estradiol can be rapidly screened by this method, demonstrating significant changes in response to an external agent. Ultimately, the proteins can be studied by peptide mapping to search for posttranslational modifications of the oncoproteins accompanying progression.

  11. 3D mapping of turbulence: a laboratory experiment

    Science.gov (United States)

    Le Louarn, Miska; Dainty, Christopher; Paterson, Carl; Tallon, Michel

    2000-07-01

    In this paper, we present the first experimental results of the 3D mapping method. 3D mapping of turbulence is a method to remove the cone effect with multiple laser guide stars and multiple deformable mirrors. A laboratory experiment was realized to verify the theoretical predictions. The setup consisted of two turbulent phase screens (made with liquid crystal devices) and a Shack-Hartmann wavefront sensor. We describe the interaction matrix involved in reconstructing Zernike commands for multiple deformable mirror from the slope measurements made from laser guide stars. It is shown that mirror commands can indeed be reconstructed with the 3D mapping method. Limiting factors of the method, brought to light by this experiment are discussed.

  12. Phase behavior of the 38-atom Lennard-Jones cluster

    International Nuclear Information System (INIS)

    Sehgal, Ray M.; Maroudas, Dimitrios; Ford, David M.

    2014-01-01

    We have developed a coarse-grained description of the phase behavior of the isolated 38-atom Lennard-Jones cluster (LJ 38 ). The model captures both the solid-solid polymorphic transitions at low temperatures and the complex cluster breakup and melting transitions at higher temperatures. For this coarse model development, we employ the manifold learning technique of diffusion mapping. The outcome of the diffusion mapping analysis over a broad temperature range indicates that two order parameters are sufficient to describe the cluster's phase behavior; we have chosen two such appropriate order parameters that are metrics of condensation and overall crystallinity. In this well-justified coarse-variable space, we calculate the cluster's free energy landscape (FEL) as a function of temperature, employing Monte Carlo umbrella sampling. These FELs are used to quantify the phase behavior and onsets of phase transitions of the LJ 38 cluster

  13. Short-Term Plasticity of the Visuomotor Map during Grasping Movements in Humans

    Science.gov (United States)

    Safstrom, Daniel; Edin, Benoni B.

    2005-01-01

    During visually guided grasping movements, visual information is transformed into motor commands. This transformation is known as the "visuomotor map." To investigate limitations in the short-term plasticity of the visuomotor map in normal humans, we studied the maximum grip aperture (MGA) during the reaching phase while subjects grasped objects…

  14. Implications of Web Mercator and its Use in Online Mapping

    Science.gov (United States)

    Battersby, Sarah E.; Finn, Michael P.; Usery, E. Lynn; Yamamoto, Kristina H.

    2014-01-01

    Online interactive maps have become a popular means of communicating with spatial data. In most online mapping systems, Web Mercator has become the dominant projection. While the Mercator projection has a long history of discussion about its inappropriateness for general-purpose mapping, particularly at the global scale, and seems to have been virtually phased out for general-purpose global-scale print maps, it has seen a resurgence in popularity in Web Mercator form. This article theorizes on how Web Mercator came to be widely used for online maps and what this might mean in terms of data display, technical aspects of map generation and distribution, design, and cognition of spatial patterns. The authors emphasize details of where the projection excels and where it does not, as well as some of its advantages and disadvantages for cartographic communication, and conclude with some research directions that may help to develop better solutions to the problem of projections for general-purpose, multi-scale Web mapping.

  15. Effects of attenuation map accuracy on attenuation-corrected micro-SPECT images

    NARCIS (Netherlands)

    Wu, C.; Gratama van Andel, H.A.; Laverman, P.; Boerman, O.C.; Beekman, F.J.

    2013-01-01

    Background In single-photon emission computed tomography (SPECT), attenuation of photon flux in tissue affects quantitative accuracy of reconstructed images. Attenuation maps derived from X-ray computed tomography (CT) can be employed for attenuation correction. The attenuation coefficients as well

  16. Geometry-induced phase transition in fluids: capillary prewetting.

    Science.gov (United States)

    Yatsyshin, Petr; Savva, Nikos; Kalliadasis, Serafim

    2013-02-01

    We report a new first-order phase transition preceding capillary condensation and corresponding to the discontinuous formation of a curved liquid meniscus. Using a mean-field microscopic approach based on the density functional theory we compute the complete phase diagram of a prototypical two-dimensional system exhibiting capillary condensation, namely that of a fluid with long-ranged dispersion intermolecular forces which is spatially confined by a substrate forming a semi-infinite rectangular pore exerting long-ranged dispersion forces on the fluid. In the T-μ plane the phase line of the new transition is tangential to the capillary condensation line at the capillary wetting temperature T(cw). The surface phase behavior of the system maps to planar wetting with the phase line of the new transition, termed capillary prewetting, mapping to the planar prewetting line. If capillary condensation is approached isothermally with T>T(cw), the meniscus forms at the capping wall and unbinds continuously, making capillary condensation a second-order phenomenon. We compute the corresponding critical exponent for the divergence of adsorption.

  17. Direct phase selection of initial phases from single-wavelength anomalous dispersion (SAD) for the improvement of electron density and ab initio structure determination.

    Science.gov (United States)

    Chen, Chung-De; Huang, Yen-Chieh; Chiang, Hsin-Lin; Hsieh, Yin-Cheng; Guan, Hong-Hsiang; Chuankhayan, Phimonphan; Chen, Chun-Jung

    2014-09-01

    Optimization of the initial phasing has been a decisive factor in the success of the subsequent electron-density modification, model building and structure determination of biological macromolecules using the single-wavelength anomalous dispersion (SAD) method. Two possible phase solutions (φ1 and φ2) generated from two symmetric phase triangles in the Harker construction for the SAD method cause the well known phase ambiguity. A novel direct phase-selection method utilizing the θ(DS) list as a criterion to select optimized phases φ(am) from φ1 or φ2 of a subset of reflections with a high percentage of correct phases to replace the corresponding initial SAD phases φ(SAD) has been developed. Based on this work, reflections with an angle θ(DS) in the range 35-145° are selected for an optimized improvement, where θ(DS) is the angle between the initial phase φ(SAD) and a preliminary density-modification (DM) phase φ(DM)(NHL). The results show that utilizing the additional direct phase-selection step prior to simple solvent flattening without phase combination using existing DM programs, such as RESOLVE or DM from CCP4, significantly improves the final phases in terms of increased correlation coefficients of electron-density maps and diminished mean phase errors. With the improved phases and density maps from the direct phase-selection method, the completeness of residues of protein molecules built with main chains and side chains is enhanced for efficient structure determination.

  18. Self-Organization in Coupled Map Scale-Free Networks

    International Nuclear Information System (INIS)

    Xiao-Ming, Liang; Zong-Hua, Liu; Hua-Ping, Lü

    2008-01-01

    We study the self-organization of phase synchronization in coupled map scale-free networks with chaotic logistic map at each node and find that a variety of ordered spatiotemporal patterns emerge spontaneously in a regime of coupling strength. These ordered behaviours will change with the increase of the average links and are robust to both the system size and parameter mismatch. A heuristic theory is given to explain the mechanism of self-organization and to figure out the regime of coupling for the ordered spatiotemporal patterns

  19. A fast image encryption algorithm based on chaotic map

    Science.gov (United States)

    Liu, Wenhao; Sun, Kehui; Zhu, Congxu

    2016-09-01

    Derived from Sine map and iterative chaotic map with infinite collapse (ICMIC), a new two-dimensional Sine ICMIC modulation map (2D-SIMM) is proposed based on a close-loop modulation coupling (CMC) model, and its chaotic performance is analyzed by means of phase diagram, Lyapunov exponent spectrum and complexity. It shows that this map has good ergodicity, hyperchaotic behavior, large maximum Lyapunov exponent and high complexity. Based on this map, a fast image encryption algorithm is proposed. In this algorithm, the confusion and diffusion processes are combined for one stage. Chaotic shift transform (CST) is proposed to efficiently change the image pixel positions, and the row and column substitutions are applied to scramble the pixel values simultaneously. The simulation and analysis results show that this algorithm has high security, low time complexity, and the abilities of resisting statistical analysis, differential, brute-force, known-plaintext and chosen-plaintext attacks.

  20. A differential algebraic integration algorithm for symplectic mappings in systems with three-dimensional magnetic field

    International Nuclear Information System (INIS)

    Chang, P.; Lee, S.Y.; Yan, Y.T.

    2006-01-01

    A differential algebraic integration algorithm is developed for symplectic mapping through a three-dimensional (3-D) magnetic field. The self-consistent reference orbit in phase space is obtained by making a canonical transformation to eliminate the linear part of the Hamiltonian. Transfer maps from the entrance to the exit of any 3-D magnetic field are then obtained through slice-by-slice symplectic integration. The particle phase-space coordinates are advanced by using the integrable polynomial procedure. This algorithm is a powerful tool to attain nonlinear maps for insertion devices in synchrotron light source or complicated magnetic field in the interaction region in high energy colliders

  1. A Differential Algebraic Integration Algorithm for Symplectic Mappings in Systems with Three-Dimensional Magnetic Field

    International Nuclear Information System (INIS)

    Chang, P

    2004-01-01

    A differential algebraic integration algorithm is developed for symplectic mapping through a three-dimensional (3-D) magnetic field. The self-consistent reference orbit in phase space is obtained by making a canonical transformation to eliminate the linear part of the Hamiltonian. Transfer maps from the entrance to the exit of any 3-D magnetic field are then obtained through slice-by-slice symplectic integration. The particle phase-space coordinates are advanced by using the integrable polynomial procedure. This algorithm is a powerful tool to attain nonlinear maps for insertion devices in synchrotron light source or complicated magnetic field in the interaction region in high energy colliders

  2. Intensity Based Seismic Hazard Map of Republic of Macedonia

    Science.gov (United States)

    Dojcinovski, Dragi; Dimiskovska, Biserka; Stojmanovska, Marta

    2016-04-01

    The territory of the Republic of Macedonia and the border terrains are among the most seismically active parts of the Balkan Peninsula belonging to the Mediterranean-Trans-Asian seismic belt. The seismological data on the R. Macedonia from the past 16 centuries point to occurrence of very strong catastrophic earthquakes. The hypocenters of the occurred earthquakes are located above the Mohorovicic discontinuity, most frequently, at a depth of 10-20 km. Accurate short -term prognosis of earthquake occurrence, i.e., simultaneous prognosis of time, place and intensity of their occurrence is still not possible. The present methods of seismic zoning have advanced to such an extent that it is with a great probability that they enable efficient protection against earthquake effects. The seismic hazard maps of the Republic of Macedonia are the result of analysis and synthesis of data from seismological, seismotectonic and other corresponding investigations necessary for definition of the expected level of seismic hazard for certain time periods. These should be amended, from time to time, with new data and scientific knowledge. The elaboration of this map does not completely solve all issues related to earthquakes, but it provides basic empirical data necessary for updating the existing regulations for construction of engineering structures in seismically active areas regulated by legal regulations and technical norms whose constituent part is the seismic hazard map. The map has been elaborated based on complex seismological and geophysical investigations of the considered area and synthesis of the results from these investigations. There were two phases of elaboration of the map. In the first phase, the map of focal zones characterized by maximum magnitudes of possible earthquakes has been elaborated. In the second phase, the intensities of expected earthquakes have been computed according to the MCS scale. The map is prognostic, i.e., it provides assessment of the

  3. Phase Singularities and Termination of Spiral Wave Reentry

    National Research Council Canada - National Science Library

    Eason, James

    2001-01-01

    In order to elucidate the mechanisms by which a strong shock terminates reentrant wavefronts, we employed phase analysis techniques to study phase singularity dynamics in a finite element model of cardiac tissue...

  4. Random projections and the optimization of an algorithm for phase retrieval

    International Nuclear Information System (INIS)

    Elser, Veit

    2003-01-01

    Iterative phase retrieval algorithms typically employ projections onto constraint subspaces to recover the unknown phases in the Fourier transform of an image, or, in the case of x-ray crystallography, the electron density of a molecule. For a general class of algorithms, where the basic iteration is specified by the difference map, solutions are associated with fixed points of the map, the attractive character of which determines the effectiveness of the algorithm. The behaviour of the difference map near fixed points is controlled by the relative orientation of the tangent spaces of the two constraint subspaces employed by the map. Since the dimensionalities involved are always large in practical applications, it is appropriate to use random matrix theory ideas to analyse the average-case convergence at fixed points. Optimal values of the γ parameters of the difference map are found which differ somewhat from the values previously obtained on the assumption of orthogonal tangent spaces

  5. Phases of N=2 necklace quivers

    Directory of Open Access Journals (Sweden)

    Antonio Amariti

    2018-01-01

    Full Text Available We classify the phases of N=2 elliptic models in terms of their global properties i.e. the spectrum of line operators. We show the agreement between the field theory and the M-theory analysis and how the phases form orbits under the action of the S-duality group which corresponds to the mapping class group of the Riemann surface in M-theory.

  6. Geomagnetism-Aided Indoor Wi-Fi Radio-Map Construction via Smartphone Crowdsourcing.

    Science.gov (United States)

    Li, Wen; Wei, Dongyan; Lai, Qifeng; Li, Xianghong; Yuan, Hong

    2018-05-08

    Wi-Fi radio-map construction is an important phase in indoor fingerprint localization systems. Traditional methods for Wi-Fi radio-map construction have the problems of being time-consuming and labor-intensive. In this paper, an indoor Wi-Fi radio-map construction method is proposed which utilizes crowdsourcing data contributed by smartphone users. We draw indoor pathway map and construct Wi-Fi radio-map without requiring manual site survey, exact floor layout and extra infrastructure support. The key novelty is that it recognizes road segments from crowdsourcing traces by a cluster based on magnetism sequence similarity and constructs an indoor pathway map with Wi-Fi signal strengths annotated on. Through experiments in real world indoor areas, the method is proved to have good performance on magnetism similarity calculation, road segment clustering and pathway map construction. The Wi-Fi radio maps constructed by crowdsourcing data are validated to provide competitive indoor localization accuracy.

  7. Geomagnetism-Aided Indoor Wi-Fi Radio-Map Construction via Smartphone Crowdsourcing

    Directory of Open Access Journals (Sweden)

    Wen Li

    2018-05-01

    Full Text Available Wi-Fi radio-map construction is an important phase in indoor fingerprint localization systems. Traditional methods for Wi-Fi radio-map construction have the problems of being time-consuming and labor-intensive. In this paper, an indoor Wi-Fi radio-map construction method is proposed which utilizes crowdsourcing data contributed by smartphone users. We draw indoor pathway map and construct Wi-Fi radio-map without requiring manual site survey, exact floor layout and extra infrastructure support. The key novelty is that it recognizes road segments from crowdsourcing traces by a cluster based on magnetism sequence similarity and constructs an indoor pathway map with Wi-Fi signal strengths annotated on. Through experiments in real world indoor areas, the method is proved to have good performance on magnetism similarity calculation, road segment clustering and pathway map construction. The Wi-Fi radio maps constructed by crowdsourcing data are validated to provide competitive indoor localization accuracy.

  8. Mechanisms of lamellar collagen formation in connective tissues.

    Science.gov (United States)

    Ghazanfari, Samaneh; Khademhosseini, Ali; Smit, Theodoor H

    2016-08-01

    The objective of tissue engineering is to regenerate functional tissues. Engineering functional tissues requires an understanding of the mechanisms that guide the formation and evolution of structure in the extracellular matrix (ECM). In particular, the three-dimensional (3D) collagen fiber arrangement is important as it is the key structural determinant that provides mechanical integrity and biological function. In this review, we survey the current knowledge on collagen organization mechanisms that can be applied to create well-structured functional lamellar tissues and in particular intervertebral disc and cornea. Thus far, the mechanisms behind the formation of cross-aligned collagen fibers in the lamellar structures is not fully understood. We start with cell-induced collagen alignment and strain-stabilization behavior mechanisms which can explain a single anisotropically aligned collagen fiber layer. These mechanisms may explain why there is anisotropy in a single layer in the first place. However, they cannot explain why a consecutive collagen layer is laid down with an alternating alignment. Therefore, we explored another mechanism, called liquid crystal phasing. While dense concentrations of collagen show such behavior, there is little evidence that the conditions for liquid crystal phasing are actually met in vivo. Instead, lysyl aldehyde-derived collagen cross-links have been found essential for correct lamellar matrix deposition. Furthermore, we suggest that supra-cellular (tissue-level) shear stress may be instrumental in the alignment of collagen fibers. Understanding the potential mechanisms behind the lamellar collagen structure in connective tissues will lead to further improvement of the regeneration strategies of functional complex lamellar tissues. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. A novel image encryption algorithm based on a 3D chaotic map

    Science.gov (United States)

    Kanso, A.; Ghebleh, M.

    2012-07-01

    Recently [Solak E, Çokal C, Yildiz OT Biyikoǧlu T. Cryptanalysis of Fridrich's chaotic image encryption. Int J Bifur Chaos 2010;20:1405-1413] cryptanalyzed the chaotic image encryption algorithm of [Fridrich J. Symmetric ciphers based on two-dimensional chaotic maps. Int J Bifur Chaos 1998;8(6):1259-1284], which was considered a benchmark for measuring security of many image encryption algorithms. This attack can also be applied to other encryption algorithms that have a structure similar to Fridrich's algorithm, such as that of [Chen G, Mao Y, Chui, C. A symmetric image encryption scheme based on 3D chaotic cat maps. Chaos Soliton Fract 2004;21:749-761]. In this paper, we suggest a novel image encryption algorithm based on a three dimensional (3D) chaotic map that can defeat the aforementioned attack among other existing attacks. The design of the proposed algorithm is simple and efficient, and based on three phases which provide the necessary properties for a secure image encryption algorithm including the confusion and diffusion properties. In phase I, the image pixels are shuffled according to a search rule based on the 3D chaotic map. In phases II and III, 3D chaotic maps are used to scramble shuffled pixels through mixing and masking rules, respectively. Simulation results show that the suggested algorithm satisfies the required performance tests such as high level security, large key space and acceptable encryption speed. These characteristics make it a suitable candidate for use in cryptographic applications.

  10. Tissue Engineering in Regenerative Dental Therapy

    Directory of Open Access Journals (Sweden)

    Hiral Jhaveri-Desai

    2011-01-01

    Full Text Available Tissue engineering is amongst the latest exciting technologies having impacted the field of dentistry. Initially considered as a futuristic approach, tissue engineering is now being successfully applied in regenerative surgery. This article reviews the important determinants of tissue engineering and how they contribute to the improvement of wound healing and surgical outcomes in the oral region. Furthermore, we shall address the clinical applications of engineering involving oral and maxillofacial surgical and periodontal procedures along with other concepts that are still in experimental phase of development. This knowledge will aid the surgical and engineering researchers to comprehend the collaboration between these fields leading to extounding dental applications and to ever-continuing man-made miracles in the field of human science.

  11. Neural dynamics of the cognitive map in the hippocampus

    OpenAIRE

    Wagatsuma, Hiroaki; Yamaguchi, Yoko

    2007-01-01

    The rodent hippocampus has been thought to represent the spatial environment as a cognitive map. In the classical theory, the cognitive map has been explained as a consequence of the fact that different spatial regions are assigned to different cell populations in the framework of rate coding. Recently, the relation between place cell firing and local field oscillation theta in terms of theta phase precession was experimentally discovered and suggested as a temporal coding mechanism leading t...

  12. Implementation of fast macromolecular proton fraction mapping on 1.5 and 3 Tesla clinical MRI scanners: preliminary experience

    Science.gov (United States)

    Yarnykh, V.; Korostyshevskaya, A.

    2017-08-01

    Macromolecular proton fraction (MPF) is a biophysical parameter describing the amount of macromolecular protons involved into magnetization exchange with water protons in tissues. MPF represents a significant interest as a magnetic resonance imaging (MRI) biomarker of myelin for clinical applications. A recent fast MPF mapping method enabled clinical translation of MPF measurements due to time-efficient acquisition based on the single-point constrained fit algorithm. However, previous MPF mapping applications utilized only 3 Tesla MRI scanners and modified pulse sequences, which are not commonly available. This study aimed to test the feasibility of MPF mapping implementation on a 1.5 Tesla clinical scanner using standard manufacturer’s sequences and compare the performance of this method between 1.5 and 3 Tesla scanners. MPF mapping was implemented on 1.5 and 3 Tesla MRI units of one manufacturer with either optimized custom-written or standard product pulse sequences. Whole-brain three-dimensional MPF maps obtained from a single volunteer were compared between field strengths and implementation options. MPF maps demonstrated similar quality at both field strengths. MPF values in segmented brain tissues and specific anatomic regions appeared in close agreement. This experiment demonstrates the feasibility of fast MPF mapping using standard sequences on 1.5 T and 3 T clinical scanners.

  13. Phase-space networks of geometrically frustrated systems.

    Science.gov (United States)

    Han, Yilong

    2009-11-01

    We illustrate a network approach to the phase-space study by using two geometrical frustration models: antiferromagnet on triangular lattice and square ice. Their highly degenerated ground states are mapped as discrete networks such that the quantitative network analysis can be applied to phase-space studies. The resulting phase spaces share some comon features and establish a class of complex networks with unique Gaussian spectral densities. Although phase-space networks are heterogeneously connected, the systems are still ergodic due to the random Poisson processes. This network approach can be generalized to phase spaces of some other complex systems.

  14. A Pragmatic Approach to Guide Implementation Evaluation Research: Strategy Mapping for Complex Interventions

    Directory of Open Access Journals (Sweden)

    Alexis K. Huynh

    2018-05-01

    Full Text Available IntroductionGreater specification of implementation strategies is a challenge for implementation science, but there is little guidance for delineating the use of multiple strategies involved in complex interventions. The Cardiovascular (CV Toolkit project entails implementation of a toolkit designed to reduce CV risk by increasing women’s engagement in appropriate services. The CV Toolkit project follows an enhanced version of Replicating Effective Programs (REP, an evidence-based implementation strategy, to implement the CV Toolkit across four phases: pre-conditions, pre-implementation, implementation, and maintenance and evolution. Our current objective is to describe a method for mapping implementation strategies used in real time as part of the CV Toolkit project. This method supports description of the timing and content of bundled strategies and provides a structured process for developing a plan for implementation evaluation.MethodsWe conducted a process of strategy mapping to apply Proctor and colleagues’ rubric for specification of implementation strategies, constructing a matrix in which we identified each implementation strategy, its conceptual group, and the corresponding REP phase(s in which it occurs. For each strategy, we also specified the actors involved, actions undertaken, action targets, dose of the implementation strategy, and anticipated outcome addressed. We iteratively refined the matrix with the implementation team, including use of simulation to provide initial validation.ResultsMapping revealed patterns in the timing of implementation strategies within REP phases. Most implementation strategies involving the development of stakeholder interrelationships and training and educating stakeholders were introduced during the pre-conditions or pre-implementation phases. Strategies introduced in the maintenance and evolution phase emphasized communication, re-examination, and audit and feedback. In addition to its value

  15. Nanoceramics on osteoblast proliferation and differentiation in bone tissue engineering.

    Science.gov (United States)

    Sethu, Sai Nievethitha; Namashivayam, Subhapradha; Devendran, Saravanan; Nagarajan, Selvamurugan; Tsai, Wei-Bor; Narashiman, Srinivasan; Ramachandran, Murugesan; Ambigapathi, Moorthi

    2017-05-01

    Bone, a highly dynamic connective tissue, consist of a bioorganic phase comprising osteogenic cells and proteins which lies over an inorganic phase predominantly made of CaPO 4 (biological apatite). Injury to bone can be due to mechanical, metabolic or inflammatory agents also owing pathological conditions like fractures, osteomyelitis, osteolysis or cysts may arise in enameloid, chondroid, cementum, or chondroid bone which forms the intermediate tissues of the body. Bone tissue engineering (BTE) applies bioactive scaffolds, host cells and osteogenic signals for restoring damaged or diseased tissues. Various bioceramics used in BTE can be bioactive (like glass ceramics and hydroxyapatite bioactive glass), bioresorbable (like tricalcium phosphates) or bioinert (like zirconia and alumina). Limiting the size of these materials to nano-scale has resulted in a higher surface area to volume ratio thereby improving multi-functionality, solubility, surface catalytic activity, high heat and electrical conductivity. Nanoceramics have been found to induce osteoconduction, osteointegration, osteogenesis and osteoinduction. The present review aims at summarizing the interactions of nanoceramics and osteoblast/stem cells for promoting the proliferation and differentiation of the osteoblast cells by nanoceramics as superior bone substitutes in bone tissue engineering applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. A five-colour colour-coded mapping method for DCE-MRI analysis of head and neck tumours

    International Nuclear Information System (INIS)

    Yuan, J.; Chow, S.K.K.; Yeung, D.K.W.; King, A.D.

    2012-01-01

    Aim: To devise a method to convert the time–intensity curves (TICs) of head and neck dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) data into a pixel-by-pixel colour-coded map for identifying normal tissues and tumours. Materials and methods: Twenty-three patients with head and neck squamous cell carcinoma (HNSCC) underwent DCE-MRI. TIC patterns of primary tumours, metastatic nodes, and normal tissues were assessed and a program was devised to convert the patterns into a classified colour-coded map. The enhancement patterns of tumours and normal tissue structures were evaluated and categorized into nine grades (0–8) based on the predominance of coloured pixels on maps. Results: Five identified TIC patterns were converted into a colour-coded map consisting of red (maximum enhancement), brown (continuous slow rise-up), yellow (rapid wash-in and wash-out), green (rapid wash-in and plateau), and blue (rapid wash-in and rise-up). The colour-coded map distinguished all 21 primary tumours and 15 metastatic nodes from normal structures. Primary tumours and metastatic nodes were colour coded as predominantly yellow (grades 1–2) in 17/21 and 6/15, green (grades 3–5) in 3/21 and 5/15, and blue (grades 6–7) in 1/21 and 4/15, respectively. Vessels were coded red in 46/46 (grade 0) and muscles were coded brown in 23/23 (grade 8). Salivary glands, thyroid glands, and palatine tonsils were coded into predominantly yellow (grade 1) in 46/46 and 10/10 and 18/22, respectively. Conclusion: DCE-MRI derived five-colour-coded mapping provides an objective easy-to-interpret method to assess the dynamic enhancement pattern of head and neck cancers.

  17. Tissues Use Resident Dendritic Cells and Macrophages to Maintain Homeostasis and to Regain Homeostasis upon Tissue Injury: The Immunoregulatory Role of Changing Tissue Environments

    Science.gov (United States)

    Lech, Maciej; Gröbmayr, Regina; Weidenbusch, Marc; Anders, Hans-Joachim

    2012-01-01

    Most tissues harbor resident mononuclear phagocytes, that is, dendritic cells and macrophages. A classification that sufficiently covers their phenotypic heterogeneity and plasticity during homeostasis and disease does not yet exist because cell culture-based phenotypes often do not match those found in vivo. The plasticity of mononuclear phagocytes becomes obvious during dynamic or complex disease processes. Different data interpretation also originates from different conceptual perspectives. An immune-centric view assumes that a particular priming of phagocytes then causes a particular type of pathology in target tissues, conceptually similar to antigen-specific T-cell priming. A tissue-centric view assumes that changing tissue microenvironments shape the phenotypes of their resident and infiltrating mononuclear phagocytes to fulfill the tissue's need to maintain or regain homeostasis. Here we discuss the latter concept, for example, why different organs host different types of mononuclear phagocytes during homeostasis. We further discuss how injuries alter tissue environments and how this primes mononuclear phagocytes to enforce this particular environment, for example, to support host defense and pathogen clearance, to support the resolution of inflammation, to support epithelial and mesenchymal healing, and to support the resolution of fibrosis to the smallest possible scar. Thus, organ- and disease phase-specific microenvironments determine macrophage and dendritic cell heterogeneity in a temporal and spatial manner, which assures their support to maintain and regain homeostasis in whatever condition. Mononuclear phagocytes contributions to tissue pathologies relate to their central roles in orchestrating all stages of host defense and wound healing, which often become maladaptive processes, especially in sterile and/or diffuse tissue injuries. PMID:23251037

  18. Mapping gas-phase organic reactivity and concomitant secondary organic aerosol formation: chemometric dimension reduction techniques for the deconvolution of complex atmospheric data sets

    Science.gov (United States)

    Wyche, K. P.; Monks, P. S.; Smallbone, K. L.; Hamilton, J. F.; Alfarra, M. R.; Rickard, A. R.; McFiggans, G. B.; Jenkin, M. E.; Bloss, W. J.; Ryan, A. C.; Hewitt, C. N.; MacKenzie, A. R.

    2015-07-01

    Highly non-linear dynamical systems, such as those found in atmospheric chemistry, necessitate hierarchical approaches to both experiment and modelling in order to ultimately identify and achieve fundamental process-understanding in the full open system. Atmospheric simulation chambers comprise an intermediate in complexity, between a classical laboratory experiment and the full, ambient system. As such, they can generate large volumes of difficult-to-interpret data. Here we describe and implement a chemometric dimension reduction methodology for the deconvolution and interpretation of complex gas- and particle-phase composition spectra. The methodology comprises principal component analysis (PCA), hierarchical cluster analysis (HCA) and positive least-squares discriminant analysis (PLS-DA). These methods are, for the first time, applied to simultaneous gas- and particle-phase composition data obtained from a comprehensive series of environmental simulation chamber experiments focused on biogenic volatile organic compound (BVOC) photooxidation and associated secondary organic aerosol (SOA) formation. We primarily investigated the biogenic SOA precursors isoprene, α-pinene, limonene, myrcene, linalool and β-caryophyllene. The chemometric analysis is used to classify the oxidation systems and resultant SOA according to the controlling chemistry and the products formed. Results show that "model" biogenic oxidative systems can be successfully separated and classified according to their oxidation products. Furthermore, a holistic view of results obtained across both the gas- and particle-phases shows the different SOA formation chemistry, initiating in the gas-phase, proceeding to govern the differences between the various BVOC SOA compositions. The results obtained are used to describe the particle composition in the context of the oxidised gas-phase matrix. An extension of the technique, which incorporates into the statistical models data from anthropogenic (i

  19. On the accuracy and reproducibility of a novel probabilistic atlas-based generation for calculation of head attenuation maps on integrated PET/MR scanners.

    Science.gov (United States)

    Chen, Kevin T; Izquierdo-Garcia, David; Poynton, Clare B; Chonde, Daniel B; Catana, Ciprian

    2017-03-01

    To propose an MR-based method for generating continuous-valued head attenuation maps and to assess its accuracy and reproducibility. Demonstrating that novel MR-based photon attenuation correction methods are both accurate and reproducible is essential prior to using them routinely in research and clinical studies on integrated PET/MR scanners. Continuous-valued linear attenuation coefficient maps ("μ-maps") were generated by combining atlases that provided the prior probability of voxel positions belonging to a certain tissue class (air, soft tissue, or bone) and an MR intensity-based likelihood classifier to produce posterior probability maps of tissue classes. These probabilities were used as weights to generate the μ-maps. The accuracy of this probabilistic atlas-based continuous-valued μ-map ("PAC-map") generation method was assessed by calculating the voxel-wise absolute relative change (RC) between the MR-based and scaled CT-based attenuation-corrected PET images. To assess reproducibility, we performed pair-wise comparisons of the RC values obtained from the PET images reconstructed using the μ-maps generated from the data acquired at three time points. The proposed method produced continuous-valued μ-maps that qualitatively reflected the variable anatomy in patients with brain tumor and agreed well with the scaled CT-based μ-maps. The absolute RC comparing the resulting PET volumes was 1.76 ± 2.33 %, quantitatively demonstrating that the method is accurate. Additionally, we also showed that the method is highly reproducible, the mean RC value for the PET images reconstructed using the μ-maps obtained at the three visits being 0.65 ± 0.95 %. Accurate and highly reproducible continuous-valued head μ-maps can be generated from MR data using a probabilistic atlas-based approach.

  20. On the accuracy and reproducibility of a novel probabilistic atlas-based generation for calculation of head attenuation maps on integrated PET/MR scanners

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Kevin T. [Massachusetts General Hospital and Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, MA (United States); Massachusetts Institute of Technology, Division of Health Sciences and Technology, Cambridge, MA (United States); Izquierdo-Garcia, David; Catana, Ciprian [Massachusetts General Hospital and Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, MA (United States); Poynton, Clare B. [Massachusetts General Hospital and Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, MA (United States); Massachusetts General Hospital, Department of Psychiatry, Boston, MA (United States); University of California, San Francisco, Department of Radiology and Biomedical Imaging, San Francisco, CA (United States); Chonde, Daniel B. [Massachusetts General Hospital and Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, MA (United States); Harvard University, Program in Biophysics, Cambridge, MA (United States)

    2017-03-15

    To propose an MR-based method for generating continuous-valued head attenuation maps and to assess its accuracy and reproducibility. Demonstrating that novel MR-based photon attenuation correction methods are both accurate and reproducible is essential prior to using them routinely in research and clinical studies on integrated PET/MR scanners. Continuous-valued linear attenuation coefficient maps (''μ-maps'') were generated by combining atlases that provided the prior probability of voxel positions belonging to a certain tissue class (air, soft tissue, or bone) and an MR intensity-based likelihood classifier to produce posterior probability maps of tissue classes. These probabilities were used as weights to generate the μ-maps. The accuracy of this probabilistic atlas-based continuous-valued μ-map (''PAC-map'') generation method was assessed by calculating the voxel-wise absolute relative change (RC) between the MR-based and scaled CT-based attenuation-corrected PET images. To assess reproducibility, we performed pair-wise comparisons of the RC values obtained from the PET images reconstructed using the μ-maps generated from the data acquired at three time points. The proposed method produced continuous-valued μ-maps that qualitatively reflected the variable anatomy in patients with brain tumor and agreed well with the scaled CT-based μ-maps. The absolute RC comparing the resulting PET volumes was 1.76 ± 2.33 %, quantitatively demonstrating that the method is accurate. Additionally, we also showed that the method is highly reproducible, the mean RC value for the PET images reconstructed using the μ-maps obtained at the three visits being 0.65 ± 0.95 %. Accurate and highly reproducible continuous-valued head μ-maps can be generated from MR data using a probabilistic atlas-based approach. (orig.)