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Sample records for accelerated atherosclerotic process

  1. Magnetic characterization of human blood in the atherosclerotic process in coronary arteries

    NASA Astrophysics Data System (ADS)

    Janus, B.; Bućko, M. S.; Chrobak, A.; Wasilewski, J.; Zych, M.

    2011-03-01

    In the last decades there has been an increasing interest in biomagnetism—a field of biophysics concerned with the magnetic properties of living organisms. Biomagnetism focuses on the measurement of magnetic properties of biological samples in the clinical environment. Progress in this field can provide new data for the understanding of the pathomechanism of atherosclerosis and support the diagnostic options for the evaluation and treatment of atherothrombotic complications. Lyophilized human blood samples from patients with atherosclerotic lesions (calcium scoring (CS) CS>0) and without atherosclerotic lesions (CS=0) were magnetically investigated. Magnetic measurements (performed in room and low temperature) indicated significant magnetic differences between these two groups of patients. Atherosclerotic blood samples are characterized by higher concentration of ferrimagnetic particles (magnetite and/or maghemite) and significant changes in the superparamagnetic behaviour. This research presents that magnetometry, in combination with medical research can lead to a better understanding of iron physiology in the atherosclerotic process.

  2. Divergent JAM-C Expression Accelerates Monocyte-Derived Cell Exit from Atherosclerotic Plaques.

    PubMed

    Bradfield, Paul F; Menon, Arjun; Miljkovic-Licina, Marijana; Lee, Boris P; Fischer, Nicolas; Fish, Richard J; Kwak, Brenda; Fisher, Edward A; Imhof, Beat A

    2016-01-01

    Atherosclerosis, caused in part by monocytes in plaques, continues to be a disease that afflicts the modern world. Whilst significant steps have been made in treating this chronic inflammatory disease, questions remain on how to prevent monocyte and macrophage accumulation in atherosclerotic plaques. Junctional Adhesion Molecule C (JAM-C) expressed by vascular endothelium directs monocyte transendothelial migration in a unidirectional manner leading to increased inflammation. Here we show that interfering with JAM-C allows reverse-transendothelial migration of monocyte-derived cells, opening the way back out of the inflamed environment. To study the role of JAM-C in plaque regression we used a mouse model of atherosclerosis, and tested the impact of vascular JAM-C expression levels on monocyte reverse transendothelial migration using human cells. Studies in-vitro under inflammatory conditions revealed that overexpression or gene silencing of JAM-C in human endothelium exposed to flow resulted in higher rates of monocyte reverse-transendothelial migration, similar to antibody blockade. We then transplanted atherosclerotic, plaque-containing aortic arches from hyperlipidemic ApoE-/- mice into wild-type normolipidemic recipient mice. JAM-C blockade in the recipients induced greater emigration of monocyte-derived cells and further diminished the size of atherosclerotic plaques. Our findings have shown that JAM-C forms a one-way vascular barrier for leukocyte transendothelial migration only when present at homeostatic copy numbers. We have also shown that blocking JAM-C can reduce the number of atherogenic monocytes/macrophages in plaques by emigration, providing a novel therapeutic strategy for chronic inflammatory pathologies.

  3. Divergent JAM-C Expression Accelerates Monocyte-Derived Cell Exit from Atherosclerotic Plaques

    PubMed Central

    Miljkovic-Licina, Marijana; Lee, Boris P.; Fischer, Nicolas; Fish, Richard J.; Kwak, Brenda; Fisher, Edward A.; Imhof, Beat A.

    2016-01-01

    Atherosclerosis, caused in part by monocytes in plaques, continues to be a disease that afflicts the modern world. Whilst significant steps have been made in treating this chronic inflammatory disease, questions remain on how to prevent monocyte and macrophage accumulation in atherosclerotic plaques. Junctional Adhesion Molecule C (JAM-C) expressed by vascular endothelium directs monocyte transendothelial migration in a unidirectional manner leading to increased inflammation. Here we show that interfering with JAM-C allows reverse-transendothelial migration of monocyte-derived cells, opening the way back out of the inflamed environment. To study the role of JAM-C in plaque regression we used a mouse model of atherosclerosis, and tested the impact of vascular JAM-C expression levels on monocyte reverse transendothelial migration using human cells. Studies in-vitro under inflammatory conditions revealed that overexpression or gene silencing of JAM-C in human endothelium exposed to flow resulted in higher rates of monocyte reverse-transendothelial migration, similar to antibody blockade. We then transplanted atherosclerotic, plaque-containing aortic arches from hyperlipidemic ApoE-/- mice into wild-type normolipidemic recipient mice. JAM-C blockade in the recipients induced greater emigration of monocyte-derived cells and further diminished the size of atherosclerotic plaques. Our findings have shown that JAM-C forms a one-way vascular barrier for leukocyte transendothelial migration only when present at homeostatic copy numbers. We have also shown that blocking JAM-C can reduce the number of atherogenic monocytes/macrophages in plaques by emigration, providing a novel therapeutic strategy for chronic inflammatory pathologies. PMID:27442505

  4. Accelerator simulation of astrophysical processes

    NASA Technical Reports Server (NTRS)

    Tombrello, T. A.

    1983-01-01

    Phenomena that involve accelerated ions in stellar processes that can be simulated with laboratory accelerators are described. Stellar evolutionary phases, such as the CNO cycle, have been partially explored with accelerators, up to the consumption of He by alpha particle radiative capture reactions. Further experimentation is indicated on reactions featuring N-13(p,gamma)O-14, O-15(alpha, gamma)Ne-19, and O-14(alpha,p)F-17. Accelerated beams interacting with thin foils produce reaction products that permit a determination of possible elemental abundances in stellar objects. Additionally, isotopic ratios observed in chondrites can be duplicated with accelerator beam interactions and thus constraints can be set on the conditions producing the meteorites. Data from isotopic fractionation from sputtering, i.e., blasting surface atoms from a material using a low energy ion beam, leads to possible models for processes occurring in supernova explosions. Finally, molecules can be synthesized with accelerators and compared with spectroscopic observations of stellar winds.

  5. Colorimetric Topography of Atherosclerotic Lesions by Television Image Processing

    DTIC Science & Technology

    1979-06-15

    thesis requires exposure of a grey scale. These exposures are bracketed to ± 3 f-stops centered at the meter-indicated exposure. The processed ...in atherogenesis. For this thesis , five specimens ofI’ -121- similar age, sex, and epidemiology were simulated and processed by the algorithms...6.1. Conclusion Employing the standard digitized image derived from the existing I theory of image processing , this thesis documents the development

  6. Accelerated stochastic diffusion processes

    NASA Astrophysics Data System (ADS)

    Garbaczewski, Piotr

    1990-07-01

    We give a purely probabilistic demonstration that all effects of non-random (external, conservative) forces on the diffusion process can be encoded in the Nelson ansatz for the second Newton law. Each random path of the process together with a probabilistic weight carries a phase accumulation (complex valued) weight. Random path summation (integration) of these weights leads to the transition probability density and transition amplitude respectively between two spatial points in a given time interval. The Bohm-Vigier, Fenyes-Nelson-Guerra and Feynman descriptions of the quantum particle behaviours are in fact equivalent.

  7. ESS Accelerator Cryoplant Process Design

    NASA Astrophysics Data System (ADS)

    Wang, X. L.; Arnold, P.; Hees, W.; Hildenbeutel, J.; Weisend, J. G., II

    2015-12-01

    The European Spallation Source (ESS) is a neutron-scattering facility being built with extensive international collaboration in Lund, Sweden. The ESS accelerator will deliver protons with 5 MW of power to the target at 2.0 GeV, with a nominal current of 62.5 mA. The superconducting part of the accelerator is about 300 meters long and contains 43 cryomodules. The ESS accelerator cryoplant (ACCP) will provide the cooling for the cryomodules and the cryogenic distribution system that delivers the helium to the cryomodules. The ACCP will cover three cryogenic circuits: Bath cooling for the cavities at 2 K, the thermal shields at around 40 K and the power couplers thermalisation with 4.5 K forced helium cooling. The open competitive bid for the ACCP took place in 2014 with Linde Kryotechnik AG being selected as the vendor. This paper summarizes the progress in the ACCP development and engineering. Current status including final cooling requirements, preliminary process design, system configuration, machine concept and layout, main parameters and features, solution for the acceptance tests, exergy analysis and efficiency is presented.

  8. Auroral plasma acceleration processes at Mars

    NASA Astrophysics Data System (ADS)

    Lundin, R.; Barabash, S.; Winningham, D.

    2012-09-01

    Following the first Mars Express (MEX) findings of auroral plasma acceleration above Martian magnetic anomalies[1, 2], a more detailed analysis is carried out regarding the physical processes that leads to plasma acceleration, and how they connect to the dynamo-, and energy source regions. The ultimate energy source for Martian plasma acceleration is the solar wind. The question is, by what mechanisms is solar wind energy and momentum transferred into the magnetic flux tubes that connect to Martian magnetic anomalies? What are the key plasma acceleration processes that lead to aurora and the associated ionospheric plasma outflow from Mars? The experimental setup on MEX limits our capability to carry out "auroral physics" at Mars. However, with knowledge acquired from the Earth, we may draw some analogies with terrestrial auroral physics. Using the limited data set available, consisting of primarily ASPERA and MARSIS data, an interesting picture of aurora at Mars emerges. There are some strong similarities between accelerated/heated electrons and ions in the nightside high altitude region above Mars and the electron/ion acceleration above Terrestrial discrete aurora. Nearly monoenergetic downgoing electrons are observed in conjunction with nearly monoenergetic upgoing ions. Monoenergetic counterstreaming ions and electrons is the signature of plasma acceleration in quasi-static electric fields. However, compared to the Earth's aurora, with auroral process guided by a dipole field, aurora at Mars is expected to form complex patterns in the multipole environment governed by the Martian crustal magnetic field regions. Moreover, temporal/spatial scales are different at Mars. It is therefore of interest to mention another common characteristics that exist for Earth and Mars, plasma acceleration by waves. Low-frequency, Alfvén, waves is a very powerful means of plasma acceleration in the Earth's magnetosphere. Low-frequency waves associated with plasma acceleration

  9. Lactobacillus acidophilus ATCC 4356 attenuates the atherosclerotic progression through modulation of oxidative stress and inflammatory process.

    PubMed

    Chen, Lihua; Liu, Wenen; Li, Yanming; Luo, San; Liu, Qingxia; Zhong, Yiming; Jian, Zijuan; Bao, Meihua

    2013-09-01

    The aim of this study was to investigate the effect of Lactobacillus (L.) acidophilus ATCC 4356 on the progression of atherosclerosis in Apoliprotein-E knockout (ApoE(-/-)) mice and the underlying mechanisms. Eight week-old ApoE(-/-) mice were treated with L. acidophilus ATCC 4356 daily for 12 weeks. The wild type (WT) mice or ApoE(-/-) mice in the vehicle group were treated with saline only. Body weights, serum lipid levels, aortic atherosclerotic lesions, and tissue oxidative and inflammatory statuses were examined among the groups. As compared to ApoE(-/-) mice in the vehicle group, ApoE(-/-) mice treated with L. acidophilus ATCC 4356 had no changes in body weights and serum lipid profiles, but showed decreased atherosclerotic lesion size in en face aorta. In comparison with WT mice, ApoE(-/-) mice in the vehicle group showed higher levels of serum malondialdehyde (MDA), oxidized low density lipoprotein (oxLDL) and tumor necrosis factor-alpha (TNF-α), but lower levels of interleukin-10 (IL-10) and superoxide dismutase (SOD) activities in serum. Administration of L. acidophilus ATCC 4356 could reverse these trends in a dose-dependent manner in ApoE(-/-) mice. Furthermore, ApoE(-/-) mice treated with L. acidophilus ATCC 4356 showed an inhibition of translocation of NF-κB p65 from cytoplasm to nucleus, suppression of degradation of aortic IκB-α, and improvements of gut microbiota distribution, as compared to ApoE(-/-) mice in the vehicle group. Our findings suggest that administration of L. acidophilus ATCC 4356 can attenuate the development of atherosclerotic lesions in ApoE(-/-) mice through reducing oxidative stress and inflammatory response.

  10. In vivo MRI-based simulation of fatigue process: a possible trigger for human carotid atherosclerotic plaque rupture

    PubMed Central

    2013-01-01

    Background Atherosclerotic plaque is subjected to a repetitive deformation due to arterial pulsatility during each cardiac cycle and damage may be accumulated over a time period causing fibrous cap (FC) fatigue, which may ultimately lead to rupture. In this study, we investigate the fatigue process in human carotid plaques using in vivo carotid magnetic resonance (MR) imaging. Method Twenty seven patients with atherosclerotic carotid artery disease were included in this study. Multi-sequence, high-resolution MR imaging was performed to depict the plaque structure. Twenty patients were found with ruptured FC or ulceration and 7 without. Modified Paris law was used to govern crack propagation and the propagation direction was perpendicular to the maximum principal stress at the element node located at the vulnerable site. Results The predicted crack initiations from 20 patients with FC defect all matched with the locations of the in vivo observed FC defect. Crack length increased rapidly with numerical steps. The natural logarithm of fatigue life decreased linearly with the local FC thickness (R2 = 0.67). Plaques (n=7) without FC defect had a longer fatigue life compared with those with FC defect (p = 0.03). Conclusion Fatigue process seems to explain the development of cracks in FC, which ultimately lead to plaque rupture. PMID:23617791

  11. Experiment specific processing of residual acceleration data

    NASA Technical Reports Server (NTRS)

    Rogers, Melissa J. B.; Alexander, J. I. D.

    1992-01-01

    To date, most Spacelab residual acceleration data collection projects have resulted in data bases that are overwhelming to the investigator of low-gravity experiments. This paper introduces a simple passive accelerometer system to measure low-frequency accelerations. Model responses for experiments using actual acceleration data are produced and correlations are made between experiment response and the accelerometer time history in order to test the idea that recorded acceleration data and experimental responses can be usefully correlated. Spacelab 3 accelerometer data are used as input to a variety of experiment models, and sensitivity limits are obtained for particular experiment classes. The modeling results are being used to create experiment-specific residual acceleration data processing schemes for interested investigators.

  12. In vitro angioplasty of atherosclerotic human femoral arteries: analysis of the geometrical changes in the individual tissues using MRI and image processing.

    PubMed

    Auer, Martin; Stollberger, Rudolf; Regitnig, Peter; Ebner, Franz; Holzapfel, Gerhard A

    2010-04-01

    Existing atherosclerotic plaque imaging techniques such as intravascular ultrasound, multidetector computed tomography, optical coherence tomography, and high-resolution magnetic resonance imaging (hrMRI) require computerized methods to separate and analyze the plaque morphology. In this work, we perform in vitro balloon angioplasty experiments with 10 human femoral arteries using hrMRI and image processing. The vessel segments contain low-grade to high-grade lesions with very different plaque compositions. The experiments are designed to mimic the in vivo situation. We use a semi-automatic image processing tool to extract the three-dimensional (3D) geometries of the tissue components at four characteristic stages of the angioplasty procedure. The obtained geometries are then used to determine geometrical and mechanical indices in order to characterize, classify, and analyze the atherosclerotic plaques by their specific geometrical changes. During inflation, three vessels ruptured via helical crack propagation. The adventitia, media, and intima did not preserve their area/volume during inflation; the area changes of the lipid pool during inflation were significant. The characterization of changes in individual 3D tissue geometries, together with tissue-specific mechanical properties, may serve as a basis for refined finite element (FE) modeling, which is key to better understand stress evolution in various atherosclerotic plaque configurations.

  13. Novel phases in an accelerated exclusion process

    NASA Astrophysics Data System (ADS)

    Dong, Jiajia; Klumpp, Stefan; Zia, Royce K. P.

    2013-03-01

    We introduce a class of distance-dependent interactions in an accelerated exclusion process (AEP) inspired by the cooperative speed-up observed in transcribing RNA polymerases. In the simplest scenario, each particle hops to the neighboring site if vacant and when joining a cluster of particles, triggers the frontmost particle to hop. Through both simulation and theoretical work, we discover that the steady state of AEP displays a discontinuous transition with periodic boundary condition. The system transitions from being homogeneous (with augmented currents) to phase-segregated. More surprisingly, the current-density relation in the phase-segregated state is simply J = 1 - ρ , indicating the particles (or holes) are moving at unit velocity despite the inclusion of long-range interactions. US NSF DMR- 1104820 and DMR-1005417

  14. Ultrasonic acceleration of enzymatic processing of cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Enzymatic bio-processing of cotton generates significantly less hazardous wastewater effluents, which are readily biodegradable, but it also has several critical shortcomings that impede its acceptance by industries: expensive processing costs and slow reaction rates. It has been found that the intr...

  15. Computational Tools for Accelerating Carbon Capture Process Development

    SciTech Connect

    Miller, David; Sahinidis, N V; Cozad, A; Lee, A; Kim, H; Morinelly, J; Eslick, J; Yuan, Z

    2013-06-04

    This presentation reports development of advanced computational tools to accelerate next generation technology development. These tools are to develop an optimized process using rigorous models. They include: Process Models; Simulation-Based Optimization; Optimized Process; Uncertainty Quantification; Algebraic Surrogate Models; and Superstructure Optimization (Determine Configuration).

  16. Nuclear processes and accelerated particles in solar flares

    NASA Technical Reports Server (NTRS)

    Ramaty, R.

    1987-01-01

    Nuclear processes and particle acceleration in solar flares are discussed and the theory of gamma-ray and neutron production is reviewed. Gamma-ray, neutron, and charged-particle observations of solar flares are compared with predictions, and the implications of these comparisons for particle energy spectra, total numbers, anisotropies, electron-to-proton ratios, and acceleration mechanisms are considered. Elemental and isotopic abundances of the ambient gas derived from gamma-ray observations have also been compared to abundances obtained from observations of escaping accelerated particles and other sources.

  17. Secondary electron emission from plasma processed accelerating cavity grade niobium

    NASA Astrophysics Data System (ADS)

    Basovic, Milos

    Advances in the particle accelerator technology have enabled numerous fundamental discoveries in 20th century physics. Extensive interdisciplinary research has always supported further development of accelerator technology in efforts of reaching each new energy frontier. Accelerating cavities, which are used to transfer energy to accelerated charged particles, have been one of the main focuses of research and development in the particle accelerator field. Over the last fifty years, in the race to break energy barriers, there has been constant improvement of the maximum stable accelerating field achieved in accelerating cavities. Every increase in the maximum attainable accelerating fields allowed for higher energy upgrades of existing accelerators and more compact designs of new accelerators. Each new and improved technology was faced with ever emerging limiting factors. With the standard high accelerating gradients of more than 25 MV/m, free electrons inside the cavities get accelerated by the field, gaining enough energy to produce more electrons in their interactions with the walls of the cavity. The electron production is exponential and the electron energy transfer to the walls of a cavity can trigger detrimental processes, limiting the performance of the cavity. The root cause of the free electron number gain is a phenomenon called Secondary Electron Emission (SEE). Even though the phenomenon has been known and studied over a century, there are still no effective means of controlling it. The ratio between the electrons emitted from the surface and the impacting electrons is defined as the Secondary Electron Yield (SEY). A SEY ratio larger than 1 designates an increase in the total number of electrons. In the design of accelerator cavities, the goal is to reduce the SEY to be as low as possible using any form of surface manipulation. In this dissertation, an experimental setup was developed and used to study the SEY of various sample surfaces that were treated

  18. Induction linear accelerators for commercial photon irradiation processing

    SciTech Connect

    Matthews, S.M.

    1989-01-13

    A number of proposed irradiation processes requires bulk rather than surface exposure with intense applications of ionizing radiation. Typical examples are irradiation of food packaged into pallet size containers, processing of sewer sludge for recycling as landfill and fertilizer, sterilization of prepackaged medical disposals, treatment of municipal water supplies for pathogen reduction, etc. Volumetric processing of dense, bulky products with ionizing radiation requires high energy photon sources because electrons are not penetrating enough to provide uniform bulk dose deposition in thick, dense samples. Induction Linear Accelerator (ILA) technology developed at the Lawrence Livermore National Laboratory promises to play a key role in providing solutions to this problem. This is discussed in this paper.

  19. Enzyme clustering accelerates processing of intermediates through metabolic channeling

    PubMed Central

    Castellana, Michele; Wilson, Maxwell Z.; Xu, Yifan; Joshi, Preeti; Cristea, Ileana M.; Rabinowitz, Joshua D.; Gitai, Zemer; Wingreen, Ned S.

    2015-01-01

    We present a quantitative model to demonstrate that coclustering multiple enzymes into compact agglomerates accelerates the processing of intermediates, yielding the same efficiency benefits as direct channeling, a well-known mechanism in which enzymes are funneled between enzyme active sites through a physical tunnel. The model predicts the separation and size of coclusters that maximize metabolic efficiency, and this prediction is in agreement with previously reported spacings between coclusters in mammalian cells. For direct validation, we study a metabolic branch point in Escherichia coli and experimentally confirm the model prediction that enzyme agglomerates can accelerate the processing of a shared intermediate by one branch, and thus regulate steady-state flux division. Our studies establish a quantitative framework to understand coclustering-mediated metabolic channeling and its application to both efficiency improvement and metabolic regulation. PMID:25262299

  20. Magnetohydrodynamic Particle Acceleration Processes: SSX Experiments, Theory, and Astrophysical Applications

    SciTech Connect

    Brown, Michael R.

    2006-11-16

    Project Title: Magnetohydrodynamic Particle Acceleration Processes: SSX Experiments, Theory, and Astrophysical Applications PI: Michael R. Brown, Swarthmore College The purpose of the project was to provide theoretical and modeling support to the Swarthmore Spheromak Experiment (SSX). Accordingly, the theoretical effort was tightly integrated into the SSX experimental effort. During the grant period, Michael Brown and his experimental collaborators at Swarthmore, with assistance from W. Matthaeus as appropriate, made substantial progress in understanding the physics SSX plasmas.

  1. High energy electron beam processing experiments with induction accelerators

    NASA Astrophysics Data System (ADS)

    Goodman, D. L.; Birx, D. L.; Dave, V. R.

    1995-05-01

    Induction accelerators are capable of producing very high electron beam power for processing at energies of 1-10 MeV. A high energy electron beam (HEEB) material processing system based on all-solid-state induction accelerator technology is in operation at Science Research Laboratory. The system delivers 50 ns 500 A current pulses at 1.5 MeV and is capable of operating at high power (500 kW) and high (˜ 5 kHz) repetition rate. HEEB processing with induction accelerators is useful for a wide variety of applications including the joining of high temperature materials, powder metallurgical fabrication, treatment of organic-contaminated wastewater and the curing of polymer matrix composites. High temperature HEEB experiments at SRL have demonstrated the brazing of carbon-carbon composites to metallic substrates and the melting and sintering of powders for graded-alloy fabrication. Other experiments have demonstrated efficient destruction of low-concentration organic contaminants in water and low temperature free-radical cross-linking of fiber-reinforced composites with acrylated resin matrices.

  2. Accelerating sino-atrium computer simulations with graphic processing units.

    PubMed

    Zhang, Hong; Xiao, Zheng; Lin, Shien-fong

    2015-01-01

    Sino-atrial node cells (SANCs) play a significant role in rhythmic firing. To investigate their role in arrhythmia and interactions with the atrium, computer simulations based on cellular dynamic mathematical models are generally used. However, the large-scale computation usually makes research difficult, given the limited computational power of Central Processing Units (CPUs). In this paper, an accelerating approach with Graphic Processing Units (GPUs) is proposed in a simulation consisting of the SAN tissue and the adjoining atrium. By using the operator splitting method, the computational task was made parallel. Three parallelization strategies were then put forward. The strategy with the shortest running time was further optimized by considering block size, data transfer and partition. The results showed that for a simulation with 500 SANCs and 30 atrial cells, the execution time taken by the non-optimized program decreased 62% with respect to a serial program running on CPU. The execution time decreased by 80% after the program was optimized. The larger the tissue was, the more significant the acceleration became. The results demonstrated the effectiveness of the proposed GPU-accelerating methods and their promising applications in more complicated biological simulations.

  3. Acceleration Processes in the Cusp: Observations by the FAST Satellite

    NASA Technical Reports Server (NTRS)

    Pfaff, R. F.; Carlson, C.; McFadden, J.; Ergun, R.; Clemmons, J.; Klumpar, D.; Moebius, E.; Elphic, R.; Strangeway, R.

    1999-01-01

    The Fast Auroral Snapshot (FAST) spacecraft has encountered the Earth's cusp regions near its apogee of 4175 km on numerous occasions during its first two and half years of operations. The cusp encounters are identified by their signatures of keV dispersed ion injections of solar wind origin. The FAST instruments reveal a complex microphysics inherent to many, but not all, of the cusp regions encountered by the spacecraft, that often include upgoing ion beams within regions of downgoing electrons that may appear as series of inverted-V features with energies near a few hundred eV. In many instances, upgoing electron beams have also been observed. Intense (> 100 mV/m) spikey DC-coupled electric fields and plasma waves are common features of the cusp encounters which also provide evidence for the presence of such local acceleration processes. In some cases, the FAST data show clear modulation of the precipitating magnetosheath ions indicative that they are affected by local electric potentials, as evidenced by simultaneous electron acceleration within such intervals. Furthermore, the acceleration events are sometimes organized with an apparent cellular structure that suggest Alfv6n waves or other large scale phenomena are controlling the localized potentials. We examine several cusp encounters in detail in order to study the complex relation of the cusp energetic particle populations with the plasma waves and DC electric fields.

  4. Acceleration Processes in the Cusp -- Observations by the FAST Satellite

    NASA Technical Reports Server (NTRS)

    Pfaff, R. F.; Carlson, C.; Clemmons, J.; Klumpar, D.; Moebius, E.; Elphic, R.; Strangeway, R.

    1999-01-01

    The FAST spacecraft has encountered the Earth's cusp regions near its apogee of 4175 km on numerous occasions during its first two and half years of operations. The cusp encounters are identified by their signatures of keV dispersed ion injections of solar wind origin. The FAST instruments reveal a complex microphysics inherent to many, but not all, of the cusp regions encountered by the spacecraft, that often include upgoing ion beams within regions of downgoing electrons that may appear as series of inverted-V features with energies near a few hundred eV. In many instances, upgoing electron beams have also been observed. Intense (> 100 mV/m) spikey DC-coupled electric fields and plasma waves are common features of the cusp encounters which also provide evidence for the presence of such local acceleration processes. In some cases, the FAST data show clear modulation of the precipitating magnetosheath ions indicative that they are affected by local electric potentials, as evidenced by simultaneous electron acceleration within such intervals. Furthermore, the acceleration events are sometimes organized with an apparent cellular structure that suggest Alfven waves or other large scale phenomena are controlling the localized potentials. We examine several cusp encounters in detail in order to study the complex relation of the cusp energetic particle populations with the plasma waves and DC electric fields.

  5. Particle Acceleration via Reconnection Processes in the Supersonic Solar Wind

    NASA Astrophysics Data System (ADS)

    Zank, G. P.; le Roux, J. A.; Webb, G. M.; Dosch, A.; Khabarova, O.

    2014-12-01

    An emerging paradigm for the dissipation of magnetic turbulence in the supersonic solar wind is via localized small-scale reconnection processes, essentially between quasi-2D interacting magnetic islands. Charged particles trapped in merging magnetic islands can be accelerated by the electric field generated by magnetic island merging and the contraction of magnetic islands. We derive a gyrophase-averaged transport equation for particles experiencing pitch-angle scattering and energization in a super-Alfvénic flowing plasma experiencing multiple small-scale reconnection events. A simpler advection-diffusion transport equation for a nearly isotropic particle distribution is derived. The dominant charged particle energization processes are (1) the electric field induced by quasi-2D magnetic island merging and (2) magnetic island contraction. The magnetic island topology ensures that charged particles are trapped in regions where they experience repeated interactions with the induced electric field or contracting magnetic islands. Steady-state solutions of the isotropic transport equation with only the induced electric field and a fixed source yield a power-law spectrum for the accelerated particles with index α = -(3 + MA )/2, where MA is the Alfvén Mach number. Considering only magnetic island contraction yields power-law-like solutions with index -3(1 + τ c /(8τdiff)), where τ c /τdiff is the ratio of timescales between magnetic island contraction and charged particle diffusion. The general solution is a power-law-like solution with an index that depends on the Alfvén Mach number and the timescale ratio τdiff/τ c . Observed power-law distributions of energetic particles observed in the quiet supersonic solar wind at 1 AU may be a consequence of particle acceleration associated with dissipative small-scale reconnection processes in a turbulent plasma, including the widely reported c -5 (c particle speed) spectra observed by Fisk & Gloeckler and Mewaldt et

  6. Image segmentation applied to atherosclerotic lesion

    NASA Astrophysics Data System (ADS)

    Morales, R. Rodríguez; Martínez, T. E. Alarcón; Cuello, L. Sánchez; Fernández-Britto, J. E.; Taylor, Charles

    2000-10-01

    The results obtained using two techniques: a supervised method and other unsupervised for image segmentation of atherosclerotic lesions of the thoracic aorta, are presented. Segmentation was used both with and without pre-processing. In this paper, the advantages of pre-processing prior to are shown for discriminating among the different atherosclerotic lesions (fatty streaks, fibrous plaque, complicated plaques and calcified plaques) and identifying them. The results using a supervised method were poor when searching vector consisted of two components, the mean and the variance. This digital image processing was done in order to use the automated atherometric system. This methodology has been considered to be suitable for the characterization of the atherosclerotic lesions in any artery and its organ-related damage in any vascular sector or group of patients. Final results were compared with manual segmentation realized by an expert, where difference errors less than 3% were observed. It is demonstrated by extensive experimentation, using real image data, that proposed strategy is fast and robust in the environment of a personal computer.

  7. One-Dimensional Particle Processes with Acceleration/Braking Asymmetry

    NASA Astrophysics Data System (ADS)

    Furtlehner, Cyril; Lasgouttes, Jean-Marc; Samsonov, Maxim

    2012-07-01

    The slow-to-start mechanism is known to play an important role in the particular shape of the Fundamental Diagram of traffic and to be associated to hysteresis effects of traffic flow. We study this question in the context of exclusion and queueing processes, by including an asymmetry between deceleration and acceleration in the formulation of these processes. For exclusions processes, this corresponds to a multi-class process with transition asymmetry between different speed levels, while for queueing processes we consider non-reversible stochastic dependency of the service rate w.r.t. the number of clients. The relationship between these 2 families of models is analyzed on the ring geometry, along with their steady state properties. Spatial condensation phenomena and metastability are observed, depending on the level of the aforementioned asymmetry. In addition, we provide a large deviation formulation of the fundamental diagram which includes the level of fluctuations, in the canonical ensemble when the stationary state is expressed as a product form of such generalized queues.

  8. Engineering functionality gradients by dip coating process in acceleration mode.

    PubMed

    Faustini, Marco; Ceratti, Davide R; Louis, Benjamin; Boudot, Mickael; Albouy, Pierre-Antoine; Boissière, Cédric; Grosso, David

    2014-10-08

    In this work, unique functional devices exhibiting controlled gradients of properties are fabricated by dip-coating process in acceleration mode. Through this new approach, thin films with "on-demand" thickness graded profiles at the submillimeter scale are prepared in an easy and versatile way, compatible for large-scale production. The technique is adapted to several relevant materials, including sol-gel dense and mesoporous metal oxides, block copolymers, metal-organic framework colloids, and commercial photoresists. In the first part of the Article, an investigation on the effect of the dip coating speed variation on the thickness profiles is reported together with the critical roles played by the evaporation rate and by the viscosity on the fluid draining-induced film formation. In the second part, dip-coating in acceleration mode is used to induce controlled variation of functionalities by playing on structural, chemical, or dimensional variations in nano- and microsystems. In order to demonstrate the full potentiality and versatility of the technique, original graded functional devices are made including optical interferometry mirrors with bidirectional gradients, one-dimensional photonic crystals with a stop-band gradient, graded microfluidic channels, and wetting gradient to induce droplet motion.

  9. Particle acceleration via reconnection processes in the supersonic solar wind

    SciTech Connect

    Zank, G. P.; Le Roux, J. A.; Webb, G. M.; Dosch, A.; Khabarova, O.

    2014-12-10

    An emerging paradigm for the dissipation of magnetic turbulence in the supersonic solar wind is via localized small-scale reconnection processes, essentially between quasi-2D interacting magnetic islands. Charged particles trapped in merging magnetic islands can be accelerated by the electric field generated by magnetic island merging and the contraction of magnetic islands. We derive a gyrophase-averaged transport equation for particles experiencing pitch-angle scattering and energization in a super-Alfvénic flowing plasma experiencing multiple small-scale reconnection events. A simpler advection-diffusion transport equation for a nearly isotropic particle distribution is derived. The dominant charged particle energization processes are (1) the electric field induced by quasi-2D magnetic island merging and (2) magnetic island contraction. The magnetic island topology ensures that charged particles are trapped in regions where they experience repeated interactions with the induced electric field or contracting magnetic islands. Steady-state solutions of the isotropic transport equation with only the induced electric field and a fixed source yield a power-law spectrum for the accelerated particles with index α = –(3 + M{sub A} )/2, where M{sub A} is the Alfvén Mach number. Considering only magnetic island contraction yields power-law-like solutions with index –3(1 + τ {sub c}/(8τ{sub diff})), where τ {sub c}/τ{sub diff} is the ratio of timescales between magnetic island contraction and charged particle diffusion. The general solution is a power-law-like solution with an index that depends on the Alfvén Mach number and the timescale ratio τ{sub diff}/τ {sub c}. Observed power-law distributions of energetic particles observed in the quiet supersonic solar wind at 1 AU may be a consequence of particle acceleration associated with dissipative small-scale reconnection processes in a turbulent plasma, including the widely reported c {sup –5} (c particle

  10. A GPU Accelerated Simulation Program for Electron Cooling Process

    NASA Astrophysics Data System (ADS)

    Zhang, He; Huang, He; Li, Rui; Chen, Jie; Luo, Li-Shi

    2015-04-01

    Electron cooling is essential to achieve high luminosity in the medium energy electron ion collider (MIEC) project at Jefferson Lab. Bunched electron beam with energy above 50 MeV is used to cool coasting and/or bunched ion beams. Although the conventional electron cooling technique has been widely used, such an implementation in MEIC is still challenging. We are developing a simulation program for the electron cooling process to fulfill the need of the electron cooling system design for MEIC. The program simulates the evolution of the ion beam under the intrabeam scattering (IBS) effect and the electron cooling effect using Monte Carlo method. To accelerate the calculation, the program is developed on a GPU platform. We will present some preliminary simulation results. Work supported by the Department of Energy, Laboratory Directed Research and Development Funding, under Contract No. DE-AC05-06OR23177.

  11. Research Progress on the Risk Factors and Outcomes of Human Carotid Atherosclerotic Plaques

    PubMed Central

    Xiong, Xiang-Dong; Xiong, Wei-Dong; Xiong, Shang-Shen; Chen, Gui-Hai

    2017-01-01

    Objective: Atherosclerosis is an inflammatory process that results in complex lesions or plaques that protrude into the arterial lumen. Carotid atherosclerotic plaque rupture, with distal atheromatous debris embolization, causes cerebrovascular events. This review aimed to explore research progress on the risk factors and outcomes of human carotid atherosclerotic plaques, and the molecular and cellular mechanisms of human carotid atherosclerotic plaque vulnerability for therapeutic intervention. Data Sources: We searched the PubMed database for recently published research articles up to June 2016, with the key words of “risk factors”, “outcomes”, “blood components”, “molecular mechanisms”, “cellular mechanisms”, and “human carotid atherosclerotic plaques”. Study Selection: The articles, regarding the latest developments related to the risk factors and outcomes, atherosclerotic plaque composition, blood components, and consequences of human carotid atherosclerotic plaques, and the molecular and cellular mechanisms of human carotid atherosclerotic plaque vulnerability for therapeutic intervention, were selected. Results: This review described the latest researches regarding the interactive effects of both traditional and novel risk factors for human carotid atherosclerotic plaques, novel insights into human carotid atherosclerotic plaque composition and blood components, and consequences of human carotid atherosclerotic plaque. Conclusion: Carotid plaque biology and serologic biomarkers of vulnerability can be used to predict the risk of cerebrovascular events. Furthermore, plaque composition, rather than lesion burden, seems to most predict rupture and subsequent thrombosis. PMID:28303857

  12. GPU accelerated processing of astronomical high frame-rate videosequences

    NASA Astrophysics Data System (ADS)

    Vítek, Stanislav; Švihlík, Jan; Krasula, Lukáš; Fliegel, Karel; Páta, Petr

    2015-09-01

    Astronomical instruments located around the world are producing an incredibly large amount of possibly interesting scientific data. Astronomical research is expanding into large and highly sensitive telescopes. Total volume of data rates per night of operations also increases with the quality and resolution of state-of-the-art CCD/CMOS detectors. Since many of the ground-based astronomical experiments are placed in remote locations with limited access to the Internet, it is necessary to solve the problem of the data storage. It mostly means that current data acquistion, processing and analyses algorithm require review. Decision about importance of the data has to be taken in very short time. This work deals with GPU accelerated processing of high frame-rate astronomical video-sequences, mostly originating from experiment MAIA (Meteor Automatic Imager and Analyser), an instrument primarily focused to observing of faint meteoric events with a high time resolution. The instrument with price bellow 2000 euro consists of image intensifier and gigabite ethernet camera running at 61 fps. With resolution better than VGA the system produces up to 2TB of scientifically valuable video data per night. Main goal of the paper is not to optimize any GPU algorithm, but to propose and evaluate parallel GPU algorithms able to process huge amount of video-sequences in order to delete all uninteresting data.

  13. Accelerated Searches of Gravitational Waves Using Graphics Processing Units

    NASA Astrophysics Data System (ADS)

    Chung, Shin Kee; Wen, Linqing; Blair, David; Cannon, Kipp

    2010-06-01

    The existence of gravitational waves was predicted by Albert Einstein. Black hole and neutron star binary systems will product strong gravitational waves through their inspiral and eventual merger. The analysis of the gravitational wave data is computationally intensive, requiring matched filtering of terabytes of data with a bank of at least 3000 numerical templates that represent predicted waveforms. We need to complete the analysis in real-time (within the duration of the signal) in order to enable follow-up observations with some conventional optical or radio telescopes. We report a novel application of a graphics processing units (GPUs) for the purpose of accelerating the search pipelines for gravitational waves from coalescing binary systems of compact objects. A speed-up of 16 fold in total has been achieved with an NVIDIA GeForce 8800 Ultra GPU card compared with a standard central processing unit (CPU). We show that further improvements are possible and discuss the reduction in CPU number required for the detection of inspiral sources afforded by the use of GPUs.

  14. Analyzing Collision Processes with the Smartphone Acceleration Sensor

    ERIC Educational Resources Information Center

    Vogt, Patrik; Kuhn, Jochen

    2014-01-01

    It has been illustrated several times how the built-in acceleration sensors of smartphones can be used gainfully for quantitative experiments in school and university settings (see the overview in Ref. 1 ). The physical issues in that case are manifold and apply, for example, to free fall, radial acceleration, several pendula, or the exploitation…

  15. Accelerating molecular docking calculations using graphics processing units.

    PubMed

    Korb, Oliver; Stützle, Thomas; Exner, Thomas E

    2011-04-25

    The generation of molecular conformations and the evaluation of interaction potentials are common tasks in molecular modeling applications, particularly in protein-ligand or protein-protein docking programs. In this work, we present a GPU-accelerated approach capable of speeding up these tasks considerably. For the evaluation of interaction potentials in the context of rigid protein-protein docking, the GPU-accelerated approach reached speedup factors of up to over 50 compared to an optimized CPU-based implementation. Treating the ligand and donor groups in the protein binding site as flexible, speedup factors of up to 16 can be observed in the evaluation of protein-ligand interaction potentials. Additionally, we introduce a parallel version of our protein-ligand docking algorithm PLANTS that can take advantage of this GPU-accelerated scoring function evaluation. We compared the GPU-accelerated parallel version to the same algorithm running on the CPU and also to the highly optimized sequential CPU-based version. In terms of dependence of the ligand size and the number of rotatable bonds, speedup factors of up to 10 and 7, respectively, can be observed. Finally, a fitness landscape analysis in the context of rigid protein-protein docking was performed. Using a systematic grid-based search methodology, the GPU-accelerated version outperformed the CPU-based version with speedup factors of up to 60.

  16. Emitting electron spectra and acceleration processes in the jet of PKS 0447-439

    NASA Astrophysics Data System (ADS)

    Zhou, Yao; Yan, Dahai; Dai, Benzhong; Zhang, Li

    2014-02-01

    We investigate the electron energy distributions (EEDs) and the corresponding acceleration processes in the jet of PKS 0447-439, and estimate its redshift through modeling its observed spectral energy distribution (SED) in the frame of a one-zone synchrotron-self Compton (SSC) model. Three EEDs formed in different acceleration scenarios are assumed: the power-law with exponential cut-off (PLC) EED (shock-acceleration scenario or the case of the EED approaching equilibrium in the stochastic-acceleration scenario), the log-parabolic (LP) EED (stochastic-acceleration scenario and the acceleration dominating), and the broken power-law (BPL) EED (no acceleration scenario). The corresponding fluxes of both synchrotron and SSC are then calculated. The model is applied to PKS 0447-439, and modeled SEDs are compared to the observed SED of this object by using the Markov Chain Monte Carlo method. The results show that the PLC model fails to fit the observed SED well, while the LP and BPL models give comparably good fits for the observed SED. The results indicate that it is possible that a stochastic acceleration process acts in the emitting region of PKS 0447-439 and the EED is far from equilibrium (acceleration dominating) or no acceleration process works (in the emitting region). The redshift of PKS 0447-439 is also estimated in our fitting: z = 0.16 ± 0.05 for the LP case and z = 0.17 ± 0.04 for BPL case.

  17. 77 FR 21991 - Federal Housing Administration (FHA): Multifamily Accelerated Processing (MAP)-Lender and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-12

    ... URBAN DEVELOPMENT Federal Housing Administration (FHA): Multifamily Accelerated Processing (MAP)--Lender and Underwriter Eligibility Criteria and Credit Watch for MAP Lenders AGENCY: Office of the Assistant... processes for determining lender and underwriter eligibility and tier qualification for MAP...

  18. Observations of shock acceleration processes in the solar wind

    NASA Technical Reports Server (NTRS)

    Scholer, M.

    1986-01-01

    Substantial evidence was accumulated over more than two decades that ion acceleration occurs at all collisionless shocks sampled directly in the solar system. The various shock waves in the heliosphere and the associated energetic particle phenomena are shown schematically. Three shocks have attracted considerable attention in recent years: corotating shocks due to the interaction of fast and slow solar wind streams during solar minimum, travelling interplanetary shocks due to coronal mass ejections, and planetary bow shocks. The signatures of these shocks and of their energetic particles are briefly reviewed. The most prominent theoretical models for shock acceleration are also reviewed. Recent observations at the earth's bow shock and at quasi-parallel interplanetary shocks are discussed in detail.

  19. Accelerators for E-beam and X-ray processing

    NASA Astrophysics Data System (ADS)

    Auslender, V. L.; Bryazgin, A. A.; Faktorovich, B. L.; Gorbunov, V. A.; Kokin, E. N.; Korobeinikov, M. V.; Krainov, G. S.; Lukin, A. N.; Maximov, S. A.; Nekhaev, V. E.; Panfilov, A. D.; Radchenko, V. N.; Tkachenko, V. O.; Tuvik, A. A.; Voronin, L. A.

    2002-03-01

    During last years the demand for pasteurization and desinsection of various food products (meat, chicken, sea products, vegetables, fruits, etc.) had increased. The treatment of these products in industrial scale requires the usage of powerful electron accelerators with energy 5-10 MeV and beam power at least 50 kW or more. The report describes the ILU accelerators with energy range up to 10 MeV and beam power up to 150 kW.The different irradiation schemes in electron beam and X-ray modes for various products are described. The design of the X-ray converter and 90° beam bending system are also given.

  20. Microscopic Processes On Radiation from Accelerated Particles in Relativistic Jets

    NASA Technical Reports Server (NTRS)

    Nishikawa, K.-I.; Hardee, P. E.; Mizuno, Y.; Medvedev, M.; Zhang, B.; Sol, H.; Niemiec, J.; Pohl, M.; Nordlund, A.; Fredriksen, J.; Lyubarsky, Y.; Hartmann, D. H.; Fishman, G. J.

    2009-01-01

    Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., gamma-ray bursts (GRBs), active galactic nuclei (AGNs), and Galactic microquasar systems usually have power-law emission spectra. Recent PIC simulations of relativistic electron-ion (electro-positron) jets injected into a stationary medium show that particle acceleration occurs within the downstream jet. In the collisionless relativistic shock particle acceleration is due to plasma waves and their associated instabilities (e.g., the Buneman instability, other two-streaming instability, and the Weibel (filamentation) instability) created in the shocks are responsible for particle (electron, positron, and ion) acceleration. The simulation results show that the Weibel instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields. These magnetic fields contribute to the electron's transverse deflection behind the jet head. The jitter'' radiation from deflected electrons has different properties than synchrotron radiation which is calculated in a uniform magnetic field. This jitter radiation may be important to understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets, and supernova remnants.

  1. Accelerate!

    PubMed

    Kotter, John P

    2012-11-01

    The old ways of setting and implementing strategy are failing us, writes the author of Leading Change, in part because we can no longer keep up with the pace of change. Organizational leaders are torn between trying to stay ahead of increasingly fierce competition and needing to deliver this year's results. Although traditional hierarchies and managerial processes--the components of a company's "operating system"--can meet the daily demands of running an enterprise, they are rarely equipped to identify important hazards quickly, formulate creative strategic initiatives nimbly, and implement them speedily. The solution Kotter offers is a second system--an agile, networklike structure--that operates in concert with the first to create a dual operating system. In such a system the hierarchy can hand off the pursuit of big strategic initiatives to the strategy network, freeing itself to focus on incremental changes to improve efficiency. The network is populated by employees from all levels of the organization, giving it organizational knowledge, relationships, credibility, and influence. It can Liberate information from silos with ease. It has a dynamic structure free of bureaucratic layers, permitting a level of individualism, creativity, and innovation beyond the reach of any hierarchy. The network's core is a guiding coalition that represents each level and department in the hierarchy, with a broad range of skills. Its drivers are members of a "volunteer army" who are energized by and committed to the coalition's vividly formulated, high-stakes vision and strategy. Kotter has helped eight organizations, public and private, build dual operating systems over the past three years. He predicts that such systems will lead to long-term success in the 21st century--for shareholders, customers, employees, and companies themselves.

  2. Accelerating the FE-Simulation of Roll Forming Processes with the Aid of specific Process's Properties

    NASA Astrophysics Data System (ADS)

    Abrass, Ahmad; Özel, Mahmut; Groche, Peter

    2011-08-01

    Roll forming is an effective and economical sheet forming process that is well-established in industry for the manufacturing of large quantities of profile-shaped products. In cold-roll forming, a metal sheet is fed through successive pairs of forming rolls until it is formed into the desired cross-sectional profile. The deformation of the sheet is complex. For this reason, the theoretical analysis is very difficult, especially, if the strain distribution and the occurring forces are to be determined [1]. The design of roll forming processes depends upon a large number of variables, which mainly relies upon experience based knowledge [2]. In order to overcome the challenges and to optimize these processes, FE-simulations are used. The simulation of these processes is time-consuming. The main objective of this work is to accelerate the simulation of roll forming processes by taking advantage of their steady state properties. These properties allow the transformation of points on the sheet metal according to a mathematical function. This transformation function is determined with the help of the finite element method and then the next forming steps are computed, based on the generated function. With the aid of this developed method, the computational time can be reduced effectively. The details of the FE-model and new numerical algorithms will be described. Furthermore, the results of numerical simulations with and without the application of the developed method will be compared regarding computational time and numerical results.

  3. Computational Tools for Accelerating Carbon Capture Process Development

    SciTech Connect

    Miller, David

    2013-01-01

    The goals of the work reported are: to develop new computational tools and models to enable industry to more rapidly develop and deploy new advanced energy technologies; to demonstrate the capabilities of the CCSI Toolset on non-proprietary case studies; and to deploy the CCSI Toolset to industry. Challenges of simulating carbon capture (and other) processes include: dealing with multiple scales (particle, device, and whole process scales); integration across scales; verification, validation, and uncertainty; and decision support. The tools cover: risk analysis and decision making; validated, high-fidelity CFD; high-resolution filtered sub-models; process design and optimization tools; advanced process control and dynamics; process models; basic data sub-models; and cross-cutting integration tools.

  4. Hardware acceleration vs. algorithmic acceleration: can GPU-based processing beat complexity optimization for CT?

    NASA Astrophysics Data System (ADS)

    Neophytou, Neophytos; Xu, Fang; Mueller, Klaus

    2007-03-01

    Three-dimensional computed tomography (CT) is a compute-intensive process, due to the large amounts of source and destination data, and this limits the speed at which a reconstruction can be obtained. There are two main approaches to cope with this problem: (i) lowering the overall computational complexity via algorithmic means, and/or (ii) running CT on specialized high-performance hardware. Since the latter requires considerable capital investment into rather inflexible hardware, the former option is all one has typically available in a traditional CPU-based computing environment. However, the emergence of programmable commodity graphics hardware (GPUs) has changed this situation in a decisive way. In this paper, we show that GPUs represent a commodity high-performance parallel architecture that resonates very well with the computational structure and operations inherent to CT. Using formal arguments as well as experiments we demonstrate that GPU-based 'brute-force' CT (i.e., CT at regular complexity) can be significantly faster than CPU-based as well as GPU-based CT with optimal complexity, at least for practical data sizes. Therefore, the answer to the title question: "Can GPU-based processing beat complexity optimization for CT?" is "Absolutely!"

  5. Studies of acceleration processes in the corona using ion measurements on the solar probe mission

    NASA Technical Reports Server (NTRS)

    Gloeckler, G.

    1978-01-01

    The energy spectra and composition of particles escaping from the Sun provide essential information on mechanisms responsible for their acceleration, and may also be used to characterize the regions where they are accelerated and confined and through which they propagate. The suprathermal energy range, which extends from solar wind energies (approximately 1 KeV) to about 1 MeV/nucleon, is of special interest to studies of nonthermal acceleration processes because a large fraction of particles is likely to be accelerated into this energy range. Data obtained from near earth observations of particles in the suprathermal energy range are reviewed. The necessary capabilities of an a ion composition experiment in the solar probe mission and the required ion measurements are discussed. A possible configuration of an instrument consisting of an electrostatic deflection system, modest post acceleration, and a time of flight versus energy system is described as well as its possible location on the spacecraft.

  6. Acceleration of the GAMESS-UK electronic structure package on graphical processing units.

    PubMed

    Wilkinson, Karl A; Sherwood, Paul; Guest, Martyn F; Naidoo, Kevin J

    2011-07-30

    The approach used to calculate the two-electron integral by many electronic structure packages including generalized atomic and molecular electronic structure system-UK has been designed for CPU-based compute units. We redesigned the two-electron compute algorithm for acceleration on a graphical processing unit (GPU). We report the acceleration strategy and illustrate it on the (ss|ss) type integrals. This strategy is general for Fortran-based codes and uses the Accelerator compiler from Portland Group International and GPU-based accelerators from Nvidia. The evaluation of (ss|ss) type integrals within calculations using Hartree Fock ab initio methods and density functional theory are accelerated by single and quad GPU hardware systems by factors of 43 and 153, respectively. The overall speedup for a single self consistent field cycle is at least a factor of eight times faster on a single GPU compared with that of a single CPU.

  7. The NADPH oxidase Nox4 has anti-atherosclerotic functions

    PubMed Central

    Schürmann, Christoph; Rezende, Flavia; Kruse, Christoph; Yasar, Yakub; Löwe, Oliver; Fork, Christian; van de Sluis, Bart; Bremer, Rolf; Weissmann, Norbert; Shah, Ajay M.; Jo, Hanjoong; Brandes, Ralf P.; Schröder, Katrin

    2015-01-01

    Aims Oxidative stress is thought to be a risk for cardiovascular disease and NADPH oxidases of the Nox family are important producers of reactive oxygen species. Within the Nox family, the NADPH oxidase Nox4 has a unique position as it is constitutively active and produces H2O2 rather than O2− . Nox4 is therefore incapable of scavenging NO and its low constitutive H2O2 production might even be beneficial. We hypothesized that Nox4 acts as an endogenous anti-atherosclerotic enzyme. Methods and results Tamoxifen-induced Nox4-knockout mice were crossed with ApoE−/− mice and spontaneous atherosclerosis under regular chow as well as accelerated atherosclerosis in response to partial carotid artery ligation under high-fat diet were determined. Deletion of Nox4 resulted in increased atherosclerosis formation in both models. Mechanistically, pro-atherosclerotic and pro-inflammatory changes in gene expression were observed prior to plaque development. Moreover, inhibition of Nox4 or deletion of the enzyme in the endothelium but not in macrophages resulted in increased adhesion of macrophages to the endothelial surface. Conclusions The H2O2-producing NADPH oxidase Nox4 is an endogenous anti-atherosclerotic enzyme. Nox4 inhibitors, currently under clinical evaluation, should be carefully monitored for cardiovascular side-effects. PMID:26385958

  8. Refining each process step to accelerate the development of biorefineries

    DOE PAGES

    Chandra, Richard P.; Ragauskas, Art J.

    2016-06-21

    Research over the past decade has been mainly focused on overcoming hurdles in the pretreatment, enzymatic hydrolysis, and fermentation steps of biochemical processing. Pretreatments have improved significantly in their ability to fractionate and recover the cellulose, hemicellulose, and lignin components of biomass while producing substrates containing carbohydrates that can be easily broken down by hydrolytic enzymes. There is a rapid movement towards pretreatment processes that incorporate mechanical treatments that make use of existing infrastructure in the pulp and paper industry, which has experienced a downturn in its traditional markets. Enzyme performance has also made great strides with breakthrough developments inmore » nonhydrolytic protein components, such as lytic polysaccharide monooxygenases, as well as the improvement of enzyme cocktails.The fermentability of pretreated and hydrolyzed sugar streams has been improved through strategies such as the use of reducing agents for detoxification, strain selection, and strain improvements. Although significant progress has been made, tremendous challenges still remain to advance each step of biochemical conversion, especially when processing woody biomass. In addition to technical and scale-up issues within each step of the bioconversion process, biomass feedstock supply and logistics challenges still remain at the forefront of biorefinery research.« less

  9. Accelerating COTS Middleware Acquisition: The i-Mate Process

    SciTech Connect

    Liu, Anna; Gorton, Ian

    2003-03-05

    Most major organizations now use some commercial-off-the-shelf middleware components to run their businesses. Key drivers behind this growth include ever-increasing Internet usage and the ongoing need to integrate heterogeneous legacy systems to streamline business processes. As organizations do more business online, they need scalable, high-performance software infrastructures to handle transactions and provide access to core systems.

  10. Refining each process step to accelerate the development of biorefineries

    SciTech Connect

    Chandra, Richard P.; Ragauskas, Art J.

    2016-06-21

    Research over the past decade has been mainly focused on overcoming hurdles in the pretreatment, enzymatic hydrolysis, and fermentation steps of biochemical processing. Pretreatments have improved significantly in their ability to fractionate and recover the cellulose, hemicellulose, and lignin components of biomass while producing substrates containing carbohydrates that can be easily broken down by hydrolytic enzymes. There is a rapid movement towards pretreatment processes that incorporate mechanical treatments that make use of existing infrastructure in the pulp and paper industry, which has experienced a downturn in its traditional markets. Enzyme performance has also made great strides with breakthrough developments in nonhydrolytic protein components, such as lytic polysaccharide monooxygenases, as well as the improvement of enzyme cocktails.The fermentability of pretreated and hydrolyzed sugar streams has been improved through strategies such as the use of reducing agents for detoxification, strain selection, and strain improvements. Although significant progress has been made, tremendous challenges still remain to advance each step of biochemical conversion, especially when processing woody biomass. In addition to technical and scale-up issues within each step of the bioconversion process, biomass feedstock supply and logistics challenges still remain at the forefront of biorefinery research.

  11. Accelerating Malware Detection via a Graphics Processing Unit

    DTIC Science & Technology

    2010-09-01

    Processing Unit . . . . . . . . . . . . . . . . . . 4 PE Portable Executable . . . . . . . . . . . . . . . . . . . . . 4 COFF Common Object File Format...operating systems for the future [Szo05]. The PE format is an updated version of the common object file format ( COFF ) [Mic06]. Microsoft released a new...pro.mspx, Accessed July 2010, 2001. 79 Mic06. Microsoft. Common object file format ( coff ). MSDN, November 2006. Re- vision 4.1. Mic07a. Microsoft

  12. Graphics Processing Unit Accelerated Hirsch-Fye Quantum Monte Carlo

    NASA Astrophysics Data System (ADS)

    Moore, Conrad; Abu Asal, Sameer; Rajagoplan, Kaushik; Poliakoff, David; Caprino, Joseph; Tomko, Karen; Thakur, Bhupender; Yang, Shuxiang; Moreno, Juana; Jarrell, Mark

    2012-02-01

    In Dynamical Mean Field Theory and its cluster extensions, such as the Dynamic Cluster Algorithm, the bottleneck of the algorithm is solving the self-consistency equations with an impurity solver. Hirsch-Fye Quantum Monte Carlo is one of the most commonly used impurity and cluster solvers. This work implements optimizations of the algorithm, such as enabling large data re-use, suitable for the Graphics Processing Unit (GPU) architecture. The GPU's sheer number of concurrent parallel computations and large bandwidth to many shared memories takes advantage of the inherent parallelism in the Green function update and measurement routines, and can substantially improve the efficiency of the Hirsch-Fye impurity solver.

  13. Microwave heating and the acceleration of polymerization processes

    NASA Astrophysics Data System (ADS)

    Parodi, Fabrizio

    1999-12-01

    Microwave power irradiation of dielectrics is nowadays well recognized and extensively used as an exceptionally efficient and versatile heating technique. Besides this, it revealed since the early 1980s an unexpected, and still far from being elucidated, capacity of causing reaction and yield enhancements in a great variety of chemical processes. These phenomena are currently referred to as specific or nonthermal effects of microwaves. An overview of them and their interpretations given to date in achievements in the microwave processing of slow-curing thermosetting resins is also given. Tailored, quaternary cyanoalkoxyalkyl ammonium halide catalysts, further emphasizing the microwave enhancements of curing kinetics of isocyanate/epoxy and epoxy/anhydride resin systems, are here presented. Their catalytic efficiency under microwave irradiation, microwave heatability, and dielectric properties are discussed and interpreted by the aid of the result of semi-empirical quantum mechanics calculations and molecule dynamics simulations in vacuo. An ion-hopping conduction mechanism has been recognized as the dominant source of the microwave absorption capacities of these catalysts. Dipolar relaxation losses by their strongly dipolar cations, viceversa, would preferably be responsible for the peculiar catalytic effects displayed under microwave heating. This would occur through a well-focused, molecular microwave overheating of intermediate reactive anionic groupings, they could indirectly cause as the nearest neighbors of such negatively-charged molecular sites.

  14. Accelerating radio astronomy cross-correlation with graphics processing units

    NASA Astrophysics Data System (ADS)

    Clark, M. A.; LaPlante, P. C.; Greenhill, L. J.

    2013-05-01

    We present a highly parallel implementation of the cross-correlation of time-series data using graphics processing units (GPUs), which is scalable to hundreds of independent inputs and suitable for the processing of signals from 'large-Formula' arrays of many radio antennas. The computational part of the algorithm, the X-engine, is implemented efficiently on NVIDIA's Fermi architecture, sustaining up to 79% of the peak single-precision floating-point throughput. We compare performance obtained for hardware- and software-managed caches, observing significantly better performance for the latter. The high performance reported involves use of a multi-level data tiling strategy in memory and use of a pipelined algorithm with simultaneous computation and transfer of data from host to device memory. The speed of code development, flexibility, and low cost of the GPU implementations compared with application-specific integrated circuit (ASIC) and field programmable gate array (FPGA) implementations have the potential to greatly shorten the cycle of correlator development and deployment, for cases where some power-consumption penalty can be tolerated.

  15. Graphics processing units accelerated semiclassical initial value representation molecular dynamics

    SciTech Connect

    Tamascelli, Dario; Dambrosio, Francesco Saverio; Conte, Riccardo; Ceotto, Michele

    2014-05-07

    This paper presents a Graphics Processing Units (GPUs) implementation of the Semiclassical Initial Value Representation (SC-IVR) propagator for vibrational molecular spectroscopy calculations. The time-averaging formulation of the SC-IVR for power spectrum calculations is employed. Details about the GPU implementation of the semiclassical code are provided. Four molecules with an increasing number of atoms are considered and the GPU-calculated vibrational frequencies perfectly match the benchmark values. The computational time scaling of two GPUs (NVIDIA Tesla C2075 and Kepler K20), respectively, versus two CPUs (Intel Core i5 and Intel Xeon E5-2687W) and the critical issues related to the GPU implementation are discussed. The resulting reduction in computational time and power consumption is significant and semiclassical GPU calculations are shown to be environment friendly.

  16. Accelerating chemical database searching using graphics processing units.

    PubMed

    Liu, Pu; Agrafiotis, Dimitris K; Rassokhin, Dmitrii N; Yang, Eric

    2011-08-22

    The utility of chemoinformatics systems depends on the accurate computer representation and efficient manipulation of chemical compounds. In such systems, a small molecule is often digitized as a large fingerprint vector, where each element indicates the presence/absence or the number of occurrences of a particular structural feature. Since in theory the number of unique features can be exceedingly large, these fingerprint vectors are usually folded into much shorter ones using hashing and modulo operations, allowing fast "in-memory" manipulation and comparison of molecules. There is increasing evidence that lossless fingerprints can substantially improve retrieval performance in chemical database searching (substructure or similarity), which have led to the development of several lossless fingerprint compression algorithms. However, any gains in storage and retrieval afforded by compression need to be weighed against the extra computational burden required for decompression before these fingerprints can be compared. Here we demonstrate that graphics processing units (GPU) can greatly alleviate this problem, enabling the practical application of lossless fingerprints on large databases. More specifically, we show that, with the help of a ~$500 ordinary video card, the entire PubChem database of ~32 million compounds can be searched in ~0.2-2 s on average, which is 2 orders of magnitude faster than a conventional CPU. If multiple query patterns are processed in batch, the speedup is even more dramatic (less than 0.02-0.2 s/query for 1000 queries). In the present study, we use the Elias gamma compression algorithm, which results in a compression ratio as high as 0.097.

  17. Graphics processing unit acceleration of computational electromagnetic methods

    NASA Astrophysics Data System (ADS)

    Inman, Matthew

    The use of Graphical Processing Units (GPU's) for scientific applications has been evolving and expanding for the decade. GPU's provide an alternative to the CPU in the creation and execution of the numerical codes that are often relied upon in to perform simulations in computational electromagnetics. While originally designed purely to display graphics on the users monitor, GPU's today are essentially powerful floating point co-processors that can be programmed not only to render complex graphics, but also perform the complex mathematical calculations often encountered in scientific computing. Currently the GPU's being produced often contain hundreds of separate cores able to access large amounts of high-speed dedicated memory. By utilizing the power offered by such a specialized processor, it is possible to drastically speed up the calculations required in computational electromagnetics. This increase in speed allows for the use of GPU based simulations in a variety of situations that the computational time has heretofore been a limiting factor in, such as in educational courses. Many situations in teaching electromagnetics often rely upon simple examples of problems due to the simulation times needed to analyze more complex problems. The use of GPU based simulations will be shown to allow demonstrations of more advanced problems than previously allowed by adapting the methods for use on the GPU. Modules will be developed for a wide variety of teaching situations utilizing the speed of the GPU to demonstrate various techniques and ideas previously unrealizable.

  18. Accelerator Production of Tritium project process waste assessment

    SciTech Connect

    Carson, S.D.; Peterson, P.K.

    1995-09-01

    DOE has made a commitment to compliance with all applicable environmental regulatory requirements. In this respect, it is important to consider and design all tritium supply alternatives so that they can comply with these requirements. The management of waste is an integral part of this activity and it is therefore necessary to estimate the quantities and specific wastes that will be generated by all tritium supply alternatives. A thorough assessment of waste streams includes waste characterization, quantification, and the identification of treatment and disposal options. The waste assessment for APT has been covered in two reports. The first report was a process waste assessment (PWA) that identified and quantified waste streams associated with both target designs and fulfilled the requirements of APT Work Breakdown Structure (WBS) Item 5.5.2.1. This second report is an expanded version of the first that includes all of the data of the first report, plus an assessment of treatment and disposal options for each waste stream identified in the initial report. The latter information was initially planned to be issued as a separate Waste Treatment and Disposal Options Assessment Report (WBS Item 5.5.2.2).

  19. Acceleration of the remediation process through interim action

    SciTech Connect

    Clark, T.R.; Throckmorton, J.D.; Hampshire, L.H.; Dalga, D.G.; Janke, R.J.

    1993-11-01

    During the Remedial Investigation and Feasibility Study (RI/FS) phase of a CERCLA cleanup, it is possible to implement interim actions at a site ``to respond to an immediate site threat or take advantage of an opportunity to significantly reduce risk quickly.`` An interim action is a short term action that addresses threats to public health and safety and is generally followed by the RI/FS process to achieve complete long term protection of human health and the environment. Typically, an interim action is small in scope and can be implemented quickly to reduce risks, such as the addition of a security fence around a known or suspected hazard, or construction of a temporary cap to reduce run-on/run-off from a contaminant source. For more specialized situations, however, the possibility exists to apply the intent of the interim action guidance to a much larger project scope. The primary focus of this paper is the discussion of the interim action approach for streamlined remedial action and presentation of an example large-scale project utilizing this approach at the Fernald Environmental Management Project (FEMP).

  20. Alginate-hyaluronan composite hydrogels accelerate wound healing process.

    PubMed

    Catanzano, O; D'Esposito, V; Acierno, S; Ambrosio, M R; De Caro, C; Avagliano, C; Russo, P; Russo, R; Miro, A; Ungaro, F; Calignano, A; Formisano, P; Quaglia, F

    2015-10-20

    In this paper we propose polysaccharide hydrogels combining alginate (ALG) and hyaluronan (HA) as biofunctional platform for dermal wound repair. Hydrogels produced by internal gelation were homogeneous and easy to handle. Rheological evaluation of gelation kinetics of ALG/HA mixtures at different ratios allowed understanding the HA effect on ALG cross-linking process. Disk-shaped hydrogels, at different ALG/HA ratio, were characterized for morphology, homogeneity and mechanical properties. Results suggest that, although the presence of HA does significantly slow down gelation kinetics, the concentration of cross-links reached at the end of gelation is scarcely affected. The in vitro activity of ALG/HA dressings was tested on adipose derived multipotent adult stem cells (Ad-MSC) and an immortalized keratinocyte cell line (HaCaT). Hydrogels did not interfere with cell viability in both cells lines, but significantly promoted gap closure in a scratch assay at early (1 day) and late (5 days) stages as compared to hydrogels made of ALG alone (p<0.01 and 0.001 for Ad-MSC and HaCaT, respectively). In vivo wound healing studies, conducted on a rat model of excised wound indicated that after 5 days ALG/HA hydrogels significantly promoted wound closure as compared to ALG ones (p<0.001). Overall results demonstrate that the integration of HA in a physically cross-linked ALG hydrogel can be a versatile strategy to promote wound healing that can be easily translated in a clinical setting.

  1. Accelerating the CERCLA process using plug-in records of decision

    SciTech Connect

    Williams, E.G.; Smallbeck, D.R.

    1995-12-31

    The inefficiencies of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA or Superfund) process are well recognized. Years of study and oftentimes millions of dollars are expended at Superfund sites before any cleanup begins. An accelerated approach to the CERCLA process was designed and implemented at the Fort Ord Superfund site in Monterey County, California. The approach, developed at the same time as and in concert with the US Environmental Protection Agency`s (EPA`s) Superfund Accelerated Clean-Up Model (SACM), included the preparation of two ``plug-in`` records of decision (RODs). These RODs and the process to utilize them, were carefully designed to meet specific project objectives. Implementation of this accelerated program has allowed for a no further action designation or remediation of many areas of concern at the site up to 6 years ahead of schedule and at savings in excess of a million dollars.

  2. Approach to atherosclerotic renovascular disease: 2016

    PubMed Central

    Daloul, Reem; Morrison, Aubrey R.

    2016-01-01

    The management of atherosclerotic renal artery stenosis in patients with hypertension or impaired renal function remains a clinical dilemma. The current general consensus, supported by the results of the Angioplasty and Stenting for Renal Atherosclerotic Lesions and Cardiovascular Outcomes for Renal Artery Lesions trials, argues strongly against endovascular intervention in favor of optimal medical management. We discuss the limitations and implications of the contemporary clinical trials and present our approach and formulate clear recommendations to help with the management of patients with atherosclerotic narrowing of the renal artery. PMID:27679718

  3. Molecular aspects of anti-atherosclerotic effects of short peptides.

    PubMed

    Khavinson, V Kh; Lin'kova, N S; Evlashkina, E V; Durnova, A O; Kozlov, K L; Gutop, O E

    2014-11-01

    We studied molecular mechanisms of the vasoprotective effects of tripeptide T-38 and dipeptide RR-1. Short peptides T-38 and the RR-1 activate the processes of cell renewal in organotypic and dissociated cultures of vascular cells during aging by increasing the expression of Ki-67 and reducing the synthesis of p53 protein. T-38 and RR-1 reduce the synthesis of E-selectin, adhesion molecule involved in the formation of atherosclerotic plaques.

  4. Swarm accelerometer data processing from raw accelerations to thermospheric neutral densities

    NASA Astrophysics Data System (ADS)

    Siemes, Christian; de Teixeira da Encarnação, João; Doornbos, Eelco; van den IJssel, Jose; Kraus, Jiří; Pereštý, Radek; Grunwaldt, Ludwig; Apelbaum, Guy; Flury, Jakob; Holmdahl Olsen, Poul Erik

    2016-05-01

    The Swarm satellites were launched on November 22, 2013, and carry accelerometers and GPS receivers as part of their scientific payload. The GPS receivers do not only provide the position and time for the magnetic field measurements, but are also used for determining non-gravitational forces like drag and radiation pressure acting on the spacecraft. The accelerometers measure these forces directly, at much finer resolution than the GPS receivers, from which thermospheric neutral densities can be derived. Unfortunately, the acceleration measurements suffer from a variety of disturbances, the most prominent being slow temperature-induced bias variations and sudden bias changes. In this paper, we describe the new, improved four-stage processing that is applied for transforming the disturbed acceleration measurements into scientifically valuable thermospheric neutral densities. In the first stage, the sudden bias changes in the acceleration measurements are manually removed using a dedicated software tool. The second stage is the calibration of the accelerometer measurements against the non-gravitational accelerations derived from the GPS receiver, which includes the correction for the slow temperature-induced bias variations. The identification of validity periods for calibration and correction parameters is part of the second stage. In the third stage, the calibrated and corrected accelerations are merged with the non-gravitational accelerations derived from the observations of the GPS receiver by a weighted average in the spectral domain, where the weights depend on the frequency. The fourth stage consists of transforming the corrected and calibrated accelerations into thermospheric neutral densities. We present the first results of the processing of Swarm C acceleration measurements from June 2014 to May 2015. We started with Swarm C because its acceleration measurements contain much less disturbances than those of Swarm A and have a higher signal-to-noise ratio

  5. Quasi-steady stages in the process of premixed flame acceleration in narrow channels

    NASA Astrophysics Data System (ADS)

    Valiev, D. M.; Bychkov, V.; Akkerman, V.; Eriksson, L.-E.; Law, C. K.

    2013-09-01

    The present paper addresses the phenomenon of spontaneous acceleration of a premixed flame front propagating in micro-channels, with subsequent deflagration-to-detonation transition. It has recently been shown experimentally [M. Wu, M. Burke, S. Son, and R. Yetter, Proc. Combust. Inst. 31, 2429 (2007)], 10.1016/j.proci.2006.08.098, computationally [D. Valiev, V. Bychkov, V. Akkerman, and L.-E. Eriksson, Phys. Rev. E 80, 036317 (2009)], 10.1103/PhysRevE.80.036317, and analytically [V. Bychkov, V. Akkerman, D. Valiev, and C. K. Law, Phys. Rev. E 81, 026309 (2010)], 10.1103/PhysRevE.81.026309 that the flame acceleration undergoes different stages, from an initial exponential regime to quasi-steady fast deflagration with saturated velocity. The present work focuses on the final saturation stages in the process of flame acceleration, when the flame propagates with supersonic velocity with respect to the channel walls. It is shown that an intermediate stage may occur during acceleration with quasi-steady velocity, noticeably below the Chapman-Jouguet deflagration speed. The intermediate stage is followed by additional flame acceleration and subsequent saturation to the Chapman-Jouguet deflagration regime. We elucidate the intermediate stage by the joint effect of gas pre-compression ahead of the flame front and the hydraulic resistance. The additional acceleration is related to viscous heating at the channel walls, being of key importance at the final stages. The possibility of explosion triggering is also demonstrated.

  6. Imaging Modalities to Identity Inflammation in an Atherosclerotic Plaque

    PubMed Central

    Goel, Sunny; Miller, Avraham; Agarwal, Chirag; Zakin, Elina; Acholonu, Michael; Gidwani, Umesh; Sharma, Abhishek; Kulbak, Guy; Shani, Jacob; Chen, On

    2015-01-01

    Atherosclerosis is a chronic, progressive, multifocal arterial wall disease caused by local and systemic inflammation responsible for major cardiovascular complications such as myocardial infarction and stroke. With the recent understanding that vulnerable plaque erosion and rupture, with subsequent thrombosis, rather than luminal stenosis, is the underlying cause of acute ischemic events, there has been a shift of focus to understand the mechanisms that make an atherosclerotic plaque unstable or vulnerable to rupture. The presence of inflammation in the atherosclerotic plaque has been considered as one of the initial events which convert a stable plaque into an unstable and vulnerable plaque. This paper systemically reviews the noninvasive and invasive imaging modalities that are currently available to detect this inflammatory process, at least in the intermediate stages, and discusses the ongoing studies that will help us to better understand and identify it at the molecular level. PMID:26798515

  7. Adventitial inflammation and its interaction with intimal atherosclerotic lesions

    PubMed Central

    Akhavanpoor, Mohammadreza; Wangler, Susanne; Gleissner, Christian A.; Korosoglou, Grigorios; Katus, Hugo A.; Erbel, Christian

    2014-01-01

    The presence of adventitial inflammation in correlation with atherosclerotic lesions has been recognized for decades. In the last years, several studies have investigated the relevance and impact of adventitial inflammation on atherogenesis. In the abdominal aorta of elderly Apoe−/− mice, adventitial inflammatory structures were characterized as organized ectopic lymphoid tissue, and therefore termed adventitial tertiary lymphoid organs (ATLOs). These ATLOs possess similarities in development, structure and function to secondary lymphoid organs. A crosstalk between intimal atherosclerotic lesions and ATLOs has been suggested, and several studies could demonstrate a potential role for medial vascular smooth muscle cells in this process. We here review the development, phenotypic characteristics, and function of ATLOs in atherosclerosis. Furthermore, we discuss the possible role of medial vascular smooth muscle cells and their interaction between plaque and ATLOs. PMID:25152736

  8. Nanomanufacturing Portfolio: Manufacturing Processes and Applications to Accelerate Commercial Use of Nanomaterials

    SciTech Connect

    Industrial Technologies Program

    2011-01-05

    This brochure describes the 31 R&D projects that AMO supports to accelerate the commercial manufacture and use of nanomaterials for enhanced energy efficiency. These cost-shared projects seek to exploit the unique properties of nanomaterials to improve the functionality of industrial processes and products.

  9. Sampling frequency affects the processing of Actigraph raw acceleration data to activity counts.

    PubMed

    Brønd, Jan Christian; Arvidsson, Daniel

    2016-02-01

    ActiGraph acceleration data are processed through several steps (including band-pass filtering to attenuate unwanted signal frequencies) to generate the activity counts commonly used in physical activity research. We performed three experiments to investigate the effect of sampling frequency on the generation of activity counts. Ideal acceleration signals were produced in the MATLAB software. Thereafter, ActiGraph GT3X+ monitors were spun in a mechanical setup. Finally, 20 subjects performed walking and running wearing GT3X+ monitors. Acceleration data from all experiments were collected with different sampling frequencies, and activity counts were generated with the ActiLife software. With the default 30-Hz (or 60-Hz, 90-Hz) sampling frequency, the generation of activity counts was performed as intended with 50% attenuation of acceleration signals with a frequency of 2.5 Hz by the signal frequency band-pass filter. Frequencies above 5 Hz were eliminated totally. However, with other sampling frequencies, acceleration signals above 5 Hz escaped the band-pass filter to a varied degree and contributed to additional activity counts. Similar results were found for the spinning of the GT3X+ monitors, although the amount of activity counts generated was less, indicating that raw data stored in the GT3X+ monitor is processed. Between 600 and 1,600 more counts per minute were generated with the sampling frequencies 40 and 100 Hz compared with 30 Hz during running. Sampling frequency affects the processing of ActiGraph acceleration data to activity counts. Researchers need to be aware of this error when selecting sampling frequencies other than the default 30 Hz.

  10. Acceleration processes in the quasi-steady magnetoplasmadynamic discharge. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Boyle, M. J.

    1974-01-01

    The flow field characteristics within the discharge chamber and exhaust of a quasi-steady magnetoplasmadynamic (MPD) arcjet were examined to clarify the nature of the plasma acceleration process. The observation of discharge characteristics unperturbed by insulator ablation and terminal voltage fluctuations, first requires the satisfaction of three criteria: the use of refractory insulator materials; a mass injection geometry tailored to provide propellant to both electrode regions of the discharge; and a cathode of sufficient surface area to permit nominal MPD arcjet operation for given combinations of arc current and total mass flow. The axial velocity profile and electromagnetic discharge structure were measured for an arcjet configuration which functions nominally at 15.3 kA and 6 g/sec argon mass flow. An empirical two-flow plasma acceleration model is advanced which delineates inner and outer flow regions and accounts for the observed velocity profile and calculated thrust of the accelerator.

  11. Analysis of the Acceleration Process of SEPs by an Interplanetary Shock for Bastille Day Event

    NASA Astrophysics Data System (ADS)

    Le, G. M.; Han, Y. B.

    Based on the solar energetic particle (SEP) data from ACE and GOES satellites, the acceleration of SEP by CME-driven shock in interplanetary space was investigated. The results showed that the acceleration process of SEP by the Bastille CME-driven shock ran through the whole space from the sun to the magnetosphere. The highest energy of SEP accelerated by the shock was greater than 100MeV. A magnetic bottle associated with the CME captured a lot of high energy particles with some of them having energy greater than 100MeV. Based on magnetic field data of solar wind observed by ACE data, we found that the the magnetic bottle associated with the Bastille CME was the sheath caused by the CME in fact.

  12. RF Processing of X-Band Accelerator Structures at the NLCTA

    SciTech Connect

    Adolphsen, Chris

    2000-08-24

    During the initial phase of operation, the linacs of the Next Linear Collider (NLC) will contain roughly 5,000 X-Band accelerator structures that will accelerate beams of electrons and positrons to 250 GeV. These structures will nominally operate at an unloaded gradient of 72 MV/m. As part of the NLC R and D program, several prototype structures have been built and operated at the Next Linear Collider Test Accelerator (NLCTA) at SLAC. Here, the effect of high gradient operation on the structure performance has been studied. Significant progress was made during the past year after the NLCTA power sources were upgraded to reliably produce the required NLC power levels and beyond. This paper describes the structures, the processing methodology and the observed effects of high gradient operation.

  13. Risk-Based Decision Process for Accelerated Closure of a Nuclear Weapons Facility

    SciTech Connect

    Butler, L.; Norland, R. L.; DiSalvo, R.; Anderson, M.

    2003-02-25

    Nearly 40 years of nuclear weapons production at the Rocky Flats Environmental Technology Site (RFETS or Site) resulted in contamination of soil and underground systems and structures with hazardous substances, including plutonium, uranium and hazardous waste constituents. The Site was placed on the National Priority List in 1989. There are more than 370 Individual Hazardous Substance Sites (IHSSs) at RFETS. Accelerated cleanup and closure of RFETS is being achieved through implementation and refinement of a regulatory framework that fosters programmatic and technical innovations: (1) extensive use of ''accelerated actions'' to remediate IHSSs, (2) development of a risk-based screening process that triggers and helps define the scope of accelerated actions consistent with the final remedial action objectives for the Site, (3) use of field instrumentation for real time data collection, (4) a data management system that renders near real time field data assessment, and (5) a regulatory agency consultative process to facilitate timely decisions. This paper presents the process and interim results for these aspects of the accelerated closure program applied to Environmental Restoration activities at the Site.

  14. General description of electromagnetic radiation processes based on instantaneous charge acceleration in ''endpoints''

    SciTech Connect

    James, Clancy W.; Falcke, Heino; Huege, Tim; Ludwig, Marianne

    2011-11-15

    We present a methodology for calculating the electromagnetic radiation from accelerated charged particles. Our formulation - the 'endpoint formulation' - combines numerous results developed in the literature in relation to radiation arising from particle acceleration using a complete, and completely general, treatment. We do this by describing particle motion via a series of discrete, instantaneous acceleration events, or 'endpoints', with each such event being treated as a source of emission. This method implicitly allows for particle creation and destruction, and is suited to direct numerical implementation in either the time or frequency domains. In this paper we demonstrate the complete generality of our method for calculating the radiated field from charged particle acceleration, and show how it reduces to the classical named radiation processes such as synchrotron, Tamm's description of Vavilov-Cherenkov, and transition radiation under appropriate limits. Using this formulation, we are immediately able to answer outstanding questions regarding the phenomenology of radio emission from ultra-high-energy particle interactions in both the earth's atmosphere and the moon. In particular, our formulation makes it apparent that the dominant emission component of the Askaryan effect (coherent radio-wave radiation from high-energy particle cascades in dense media) comes from coherent 'bremsstrahlung' from particle acceleration, rather than coherent Vavilov-Cherenkov radiation.

  15. LOX-1 in atherosclerotic disease.

    PubMed

    Sawamura, Tatsuya; Wakabayashi, Ichiro; Okamura, Tomonori

    2015-02-02

    Oxidized low-density lipoprotein (LDL) exhibits various biological activities and accumulates in atheromas. LOX-1 (lectin-like oxidized LDL receptor) is the receptor that mediates oxidized LDL activity in vascular endothelial cells. Activation of LOX-1 results in oxidized LDL-induced endothelial dysfunction and hyperlipidemia-induced vascular lipid deposition. We hypothesized that LOX-1 is a candidate risk factor beyond LDL cholesterol (LDLC) and developed a novel assay to quantify LOX-1 ligand containing apoB (LAB). In men from the United States, serum LAB showed a significant positive association with carotid intima-media thickness, independent of LDLC. LAB and the LOX index (obtained by multiplying LAB by sLOX-1) were significantly associated with the incidence of coronary artery disease and ischemic stroke after adjusting for confounding factors, including non-HDL cholesterol. sLOX-1 is thought to be a better biomarker for early diagnosis of acute coronary syndrome than traditional biomarkers, including troponin T. LAB was associated with various atherosclerotic risk factors such as smoking, obesity, diabetes, diastolic hypertension, hypertriglyceridemia, and metabolic syndrome. Measurement of the soluble form of LOX-1 (sLOX-1) and LAB seems to be useful for evaluating the state and risk of atherosclerosis and atherosclerosis-related diseases. Further prospective studies using large populations and randomized clinical trials on sLOX-1, LAB, and the LOX index are needed.

  16. Uniaxial tensile testing approaches for characterisation of atherosclerotic plaques.

    PubMed

    Walsh, M T; Cunnane, E M; Mulvihill, J J; Akyildiz, A C; Gijsen, F J H; Holzapfel, G A

    2014-03-03

    The pathological changes associated with the development of atherosclerotic plaques within arterial vessels result in significant alterations to the mechanical properties of the diseased arterial wall. There are several methods available to characterise the mechanical behaviour of atherosclerotic plaque tissue, and it is the aim of this paper to review the use of uniaxial mechanical testing. In the case of atherosclerotic plaques, there are nine studies that employ uniaxial testing to characterise mechanical behaviour. A primary concern regarding this limited cohort of published studies is the wide range of testing techniques that are employed. These differing techniques have resulted in a large variance in the reported data making comparison of the mechanical behaviour of plaques from different vasculatures, and even the same vasculature, difficult and sometimes impossible. In order to address this issue, this paper proposes a more standardised protocol for uniaxial testing of diseased arterial tissue that allows for better comparisons and firmer conclusions to be drawn between studies. To develop such a protocol, this paper reviews the acquisition and storage of the tissue, the testing approaches, the post-processing techniques and the stress-strain measures employed by each of the nine studies. Future trends are also outlined to establish the role that uniaxial testing can play in the future of arterial plaque mechanical characterisation.

  17. Rapid learning-based video stereolization using graphic processing unit acceleration

    NASA Astrophysics Data System (ADS)

    Sun, Tian; Jung, Cheolkon; Wang, Lei; Kim, Joongkyu

    2016-09-01

    Video stereolization has received much attention in recent years due to the lack of stereoscopic three-dimensional (3-D) contents. Although video stereolization can enrich stereoscopic 3-D contents, it is hard to achieve automatic two-dimensional-to-3-D conversion with less computational cost. We proposed rapid learning-based video stereolization using a graphic processing unit (GPU) acceleration. We first generated an initial depth map based on learning from examples. Then, we refined the depth map using saliency and cross-bilateral filtering to make object boundaries clear. Finally, we performed depth-image-based-rendering to generate stereoscopic 3-D views. To accelerate the computation of video stereolization, we provided a parallelizable hybrid GPU-central processing unit (CPU) solution to be suitable for running on GPU. Experimental results demonstrate that the proposed method is nearly 180 times faster than CPU-based processing and achieves a good performance comparable to the-state-of-the-art ones.

  18. Distinguishing Between Quasi-static and Alfvénic Auroral Acceleration Processes

    NASA Astrophysics Data System (ADS)

    Lysak, R. L.; Song, Y.

    2013-12-01

    Models for the acceleration of auroral particles fall into two general classes. Quasi-static processes, such as double layers or magnetic mirror supported potential drops, produce a nearly monoenergetic beam of precipitating electrons and upward flowing ion beams. Time-dependent acceleration processes, often associated with kinetic Alfvén waves, can produce a broader range of energies and often have a strongly field-aligned pitch angle distribution. Both processes are associated with strong perpendicular electric fields as well as the parallel electric fields that are largely responsible for the particle acceleration. These electric fields and the related magnetic perturbations can be characterized by the ratio of the electric field to a perpendicular magnetic perturbation, which is related to the Pedersen conductivity in the static case and the Alfvén velocity in the time-dependent case. However, these considerations can be complicated by the interaction between upward and downward propagating waves. The relevant time and space scales of these processes will be assessed and the consequences for observation by orbiting spacecraft and ground-based instrumentation will be determined. These features will be illustrated by numerical simulations of the magnetosphere-ionosphere coupling with emphasis on what a virtual spacecraft passing through the simulation would be expected to observe.

  19. Challenges Encountered during the Processing of the BNL ERL 5 Cell Accelerating Cavity

    SciTech Connect

    A. Burrill; I. Ben-Zvi; R. Calaga; H. Hahn; V. Litvinenko; G. T. McIntyre; P. Kneisel; J. Mammosser; J. P. Preble; C. E. Reece; R. A. Rimmer; J. Saunders

    2007-08-01

    One of the key components for the Energy Recovery Linac being built by the Electron cooling group in the Collider Accelerator Department is the 5 cell accelerating cavity which is designed to accelerate 2 MeV electrons from the gun up to 15-20 MeV, allow them to make one pass through the ring and then decelerate them back down to 2 MeV prior to sending them to the dump. This cavity was designed by BNL and fabricated by AES in Medford, NY. Following fabrication it was sent to Thomas Jefferson Lab in VA for chemical processing, testing and assembly into a string assembly suitable for shipment back to BNL and integration into the ERL. The steps involved in this processing sequence will be reviewed and the deviations from processing of similar SRF cavities will be discussed. The lessons learned from this process are documented to help future projects where the scope is different from that normally encountered.

  20. CHALLENGES ENCOUNTERED DURING THE PROCESSING OF THE BNL ERL 5 CELL ACCELERATING CAVITY

    SciTech Connect

    BURRILL,A.

    2007-06-25

    One of the key components for the Energy Recovery Linac being built by the Electron cooling group in the Collider Accelerator Department is the 5 cell accelerating cavity which is designed to accelerate 2 MeV electrons from the gun up to 15-20 MeV, allow them to make one pass through the ring and then decelerate them back down to 2 MeV prior to sending them to the dump. This cavity was designed by BNL and fabricated by AES in Medford, NY. Following fabrication it was sent to Thomas Jefferson Lab in VA for chemical processing, testing and assembly into a string assembly suitable for shipment back to BNL for integration into the ERL. The steps involved in this processing sequence will be reviewed and the deviations from processing of similar SRF cavities will be discussed. The lessons learned from this process are documented to help future projects where the scope is different from that normally encountered.

  1. Increased platelet deposition on atherosclerotic coronary arteries.

    PubMed Central

    van Zanten, G H; de Graaf, S; Slootweg, P J; Heijnen, H F; Connolly, T M; de Groot, P G; Sixma, J J

    1994-01-01

    A ruptured atherosclerotic plaque leads to exposure of deeper layers of the plaque to flowing blood and subsequently to thrombus formation. In contrast to the wealth of data on the occurrence of thrombi, little is known about the reasons why an atherosclerotic plaque is thrombogenic. One of the reasons is the relative inaccessibility of the atherosclerotic plaque. We have circumvented this problem by using 6-microns cryostat cross sections of human coronary arteries. These sections were mounted on coverslips that were exposed to flowing blood in a rectangular perfusion chamber. In normal-appearing arteries, platelet deposition was seen on the luminal side of the intima and on the adventitia. In atherosclerotic arteries, strongly increased platelet deposition was seen on the connective tissue of specific parts of the atherosclerotic plaque. The central lipid core of an advanced plaque was not reactive towards platelets. The results indicate that the atherosclerotic plaque by itself is more thrombogenic than the normal vessel wall. To study the cause of the increased thrombus formation on the atherosclerotic plaque, perfusion studies were combined with immunohistochemical studies. Immunohistochemical studies of adhesive proteins showed enrichment of collagen types I, III, V, and VI, vitronectin, fibronectin, fibrinogen/fibrin, and thrombospondin in the atherosclerotic plaque. Laminin and collagen type IV were not enriched. von Willebrand Factor (vWF) was not present in the plaque. The pattern of increased platelet deposition in serial cross sections corresponded best with areas in which collagen types I and III were enriched, but there were also areas in the plaque where both collagens were enriched but no increased reactivity was seen. Inhibition of platelet adhesion with a large range of antibodies or specific inhibitors showed that vWF from plasma and collagen types I and/or III in the plaque were involved. Fibronectin from plasma and fibronectin, fibrinogen

  2. Acceleration of integral imaging based incoherent Fourier hologram capture using graphic processing unit.

    PubMed

    Jeong, Kyeong-Min; Kim, Hee-Seung; Hong, Sung-In; Lee, Sung-Keun; Jo, Na-Young; Kim, Yong-Soo; Lim, Hong-Gi; Park, Jae-Hyeung

    2012-10-08

    Speed enhancement of integral imaging based incoherent Fourier hologram capture using a graphic processing unit is reported. Integral imaging based method enables exact hologram capture of real-existing three-dimensional objects under regular incoherent illumination. In our implementation, we apply parallel computation scheme using the graphic processing unit, accelerating the processing speed. Using enhanced speed of hologram capture, we also implement a pseudo real-time hologram capture and optical reconstruction system. The overall operation speed is measured to be 1 frame per second.

  3. Flowsheet report for baseline actinide blanket processing for accelerator transmutation of waste

    SciTech Connect

    Walker, R.B.

    1992-04-08

    We provide a flowsheet analysis of the chemical processing of actinide and fission product materials form the actinide blanket of an accelerator-based transmutation concept. An initial liquid ion exchange step is employed to recover unburned plutonium and neptunium, so that it can be returned quickly to the transmitter. The remaining materials, consisting of fission products and trivalent actinides (americium, curium), is processed after a cooling period. A reverse Talspeak process is employed to separate these trivalent actinides from lanthanides and other fission products.

  4. Spatial structure of the neck and acceleration processes in a micropinch

    NASA Astrophysics Data System (ADS)

    Dolgov, A. N.; Klyachin, N. A.; Prokhorovich, D. E.

    2016-12-01

    It is shown that the spatial structure of the micropinch neck during the transition from magnetohydrodynamic to radiative compression and the bremsstrahlung spectrum of the discharge in the photon energy range of up to 30 keV depend on the configuration of the inner electrode of the coaxial electrode system of the micropinch discharge. Analysis of the experimental results indicates that the acceleration processes in the electron component of the micropinch plasma develop earlier than radiative compression.

  5. Performance and scalability of Fourier domain optical coherence tomography acceleration using graphics processing units.

    PubMed

    Li, Jian; Bloch, Pavel; Xu, Jing; Sarunic, Marinko V; Shannon, Lesley

    2011-05-01

    Fourier domain optical coherence tomography (FD-OCT) provides faster line rates, better resolution, and higher sensitivity for noninvasive, in vivo biomedical imaging compared to traditional time domain OCT (TD-OCT). However, because the signal processing for FD-OCT is computationally intensive, real-time FD-OCT applications demand powerful computing platforms to deliver acceptable performance. Graphics processing units (GPUs) have been used as coprocessors to accelerate FD-OCT by leveraging their relatively simple programming model to exploit thread-level parallelism. Unfortunately, GPUs do not "share" memory with their host processors, requiring additional data transfers between the GPU and CPU. In this paper, we implement a complete FD-OCT accelerator on a consumer grade GPU/CPU platform. Our data acquisition system uses spectrometer-based detection and a dual-arm interferometer topology with numerical dispersion compensation for retinal imaging. We demonstrate that the maximum line rate is dictated by the memory transfer time and not the processing time due to the GPU platform's memory model. Finally, we discuss how the performance trends of GPU-based accelerators compare to the expected future requirements of FD-OCT data rates.

  6. [Is regression of atherosclerotic plaque possible?

    PubMed

    Páramo, José A; Civeira, Fernando

    As it is well-known, a thrombus evolving into a disrupted/eroded atherosclerotic plaque causes most acute coronary syndromes. Plaque stabilization via reduction of the lipid core and/or thickening of the fibrous cap is one of the possible mechanisms accounted for the clinical benefits displayed by different anti-atherosclerotic strategies. The concept of plaque stabilization was developed to explain how lipid-lowering agents could decrease adverse coronary events without substantial modifications of the atherosclerotic lesion ('angiographic paradox'). A number of imaging modalities (vascular ultrasound and virtual histology, MRI, optical coherence tomography, positron tomography, etc.) are used for non-invasive assessment of atherosclerosis; most of them can identify plaque volume and composition beyond lumen stenosis. An 'aggressive' lipid-lowering strategy is able to reduce the plaque burden and the incidence of cardiovascular events; this may be attributable, at least in part, to plaque-stabilizing effects.

  7. In-situ plasma processing to increase the accelerating gradients of SRF cavities

    SciTech Connect

    Doleans, Marc; Afanador, Ralph; Barnhart, Debra L.; Degraff, Brian D.; Gold, Steven W.; Hannah, Brian S.; Howell, Matthew P.; Kim, Sang-Ho; Mammosser, John; McMahan, Christopher J.; Neustadt, Thomas S.; Saunders, Jeffrey W.; Tyagi, Puneet V.; Vandygriff, Daniel J.; Vandygriff, David M.; Ball, Jeffrey Allen; Blokland, Willem; Crofford, Mark T.; Lee, Sung-Woo; Stewart, Stephen; Strong, William Herb

    2015-12-31

    A new in-situ plasma processing technique is being developed at the Spallation Neutron Source (SNS) to improve the performance of the cavities in operation. The technique utilizes a low-density reactive oxygen plasma at room temperature to remove top surface hydrocarbons. The plasma processing technique increases the work function of the cavity surface and reduces the overall amount of vacuum and electron activity during cavity operation; in particular it increases the field emission onset, which enables cavity operation at higher accelerating gradients. Experimental evidence also suggests that the SEY of the Nb surface decreases after plasma processing which helps mitigating multipacting issues. This article discusses the main developments and results from the plasma processing R&D are presented and experimental results for in-situ plasma processing of dressed cavities in the SNS horizontal test apparatus.

  8. In-situ plasma processing to increase the accelerating gradients of SRF cavities

    DOE PAGES

    Doleans, Marc; Afanador, Ralph; Barnhart, Debra L.; ...

    2015-12-31

    A new in-situ plasma processing technique is being developed at the Spallation Neutron Source (SNS) to improve the performance of the cavities in operation. The technique utilizes a low-density reactive oxygen plasma at room temperature to remove top surface hydrocarbons. The plasma processing technique increases the work function of the cavity surface and reduces the overall amount of vacuum and electron activity during cavity operation; in particular it increases the field emission onset, which enables cavity operation at higher accelerating gradients. Experimental evidence also suggests that the SEY of the Nb surface decreases after plasma processing which helps mitigating multipactingmore » issues. This article discusses the main developments and results from the plasma processing R&D are presented and experimental results for in-situ plasma processing of dressed cavities in the SNS horizontal test apparatus.« less

  9. Activation processes in a medical linear accelerator and spatial distribution of activation products.

    PubMed

    Fischer, Helmut W; Tabot, Ben E; Poppe, Björn

    2006-12-21

    Activation products have been identified by in situ gamma spectroscopy at the isocentre of a medical linear accelerator shortly after termination of a high energy photon beam irradiation with 15 x 15 cm field size. Spectra have been recorded either with an open or with a closed collimator. Whilst some activation products disappear from the spectrum with closed collimator or exhibit reduced count rates, others remain with identical intensity. The former isotopes are neutron-deficient and mostly decay by positron emission or electron capture; the latter have neutron excess and decay by beta(-) emission. This new finding is consistent with the assumption that photons in the primary beam produce activation products by (gamma, n) reactions in the treatment head and subsequently the neutrons created in these processes undergo (n, gamma) reactions creating activation products in a much larger area. These findings are expected to be generally applicable to all medical high energy linear accelerators.

  10. Using graphics processing units to accelerate perturbation Monte Carlo simulation in a turbid medium

    NASA Astrophysics Data System (ADS)

    Cai, Fuhong; He, Sailing

    2012-04-01

    We report a fast perturbation Monte Carlo (PMC) algorithm accelerated by graphics processing units (GPU). The two-step PMC simulation [Opt. Lett. 36, 2095 (2011)] is performed by storing the seeds instead of the photon's trajectory, and thus the requirement in computer random-access memory (RAM) becomes minimal. The two-step PMC is extremely suitable for implementation onto GPU. In a standard simulation of spatially-resolved photon migration in the turbid media, the acceleration ratio between using GPU and using conventional CPU is about 1000. Furthermore, since in the two-step PMC algorithm one records the effective seeds, which is associated to the photon that reaches a region of interest in this letter, and then re-run the MC simulation based on the recorded effective seeds, radiative transfer equation (RTE) can be solved by two-step PMC not only with an arbitrary change in the absorption coefficient, but also with large change in the scattering coefficient.

  11. Using graphics processing units to accelerate perturbation Monte Carlo simulation in a turbid medium.

    PubMed

    Cai, Fuhong; He, Sailing

    2012-04-01

    We report a fast perturbation Monte Carlo (PMC) algorithm accelerated by graphics processing units (GPU). The two-step PMC simulation [Opt. Lett. 36, 2095 (2011)] is performed by storing the seeds instead of the photon's trajectory, and thus the requirement in computer random-access memory (RAM) becomes minimal. The two-step PMC is extremely suitable for implementation onto GPU. In a standard simulation of spatially-resolved photon migration in the turbid media, the acceleration ratio between using GPU and using conventional CPU is about 1000. Furthermore, since in the two-step PMC algorithm one records the effective seeds, which is associated to the photon that reaches a region of interest in this letter, and then re-run the MC simulation based on the recorded effective seeds, radiative transfer equation (RTE) can be solved by two-step PMC not only with an arbitrary change in the absorption coefficient, but also with large change in the scattering coefficient.

  12. Plasma Processing of SRF Cavities for the next Generation Of Particle Accelerators

    SciTech Connect

    Vuskovic, Leposava

    2015-11-23

    The cost-effective production of high frequency accelerating fields are the foundation for the next generation of particle accelerators. The Ar/Cl2 plasma etching technology holds the promise to yield a major reduction in cavity preparation costs. Plasma-based dry niobium surface treatment provides an excellent opportunity to remove bulk niobium, eliminate surface imperfections, increase cavity quality factor, and bring accelerating fields to higher levels. At the same time, the developed technology will be more environmentally friendly than the hydrogen fluoride-based wet etching technology. Plasma etching of inner surfaces of standard multi-cell SRF cavities is the main goal of this research in order to eliminate contaminants, including niobium oxides, in the penetration depth region. Successful plasma processing of multi-cell cavities will establish this method as a viable technique in the quest for more efficient components of next generation particle accelerators. In this project the single-cell pill box cavity plasma etching system is developed and etching conditions are determined. An actual single cell SRF cavity (1497 MHz) is plasma etched based on the pill box cavity results. The first RF test of this plasma etched cavity at cryogenic temperature is obtained. The system can also be used for other surface modifications, including tailoring niobium surface properties, surface passivation or nitriding for better performance of SRF cavities. The results of this plasma processing technology may be applied to most of the current SRF cavity fabrication projects. In the course of this project it has been demonstrated that a capacitively coupled radio-frequency discharge can be successfully used for etching curved niobium surfaces, in particular the inner walls of SRF cavities. The results could also be applicable to the inner or concave surfaces of any 3D structure other than an SRF cavity.

  13. Hybrid-integrated optical acceleration seismometer and its digital processing system

    NASA Astrophysics Data System (ADS)

    En, De; Chen, Caihe; Cui, Yuming; Tang, Donglin; Liang, Zhengxi; Gao, Hongyu

    2005-02-01

    Hybrid-integrated Optical acceleration seismometer and its digital signal processing system are researched and developed. The simple system figure of the seismometer is given. The principle of the seismometer is explicated. The seismometer is composed of a seismic mass,Integrated Optical Chips and a set of Michelson interferometer light path. The Michelson Integrated Optical Chips are critical parts among the sensor elements. The simple figure of the digital signal processing system is given. As an advanced quality digital signal processing (DSP) chip equipped with necessary circuits has been used in its digital signal processing system, a high accurate detection of the acceleration signal has been achieved and the environmental interference signal has been effectively compensated. Test results indicate that the accelerometer has better frequency response well above the resonant frequency, and the output signal is in correspondence with the input signal. The accelerometer also has better frequency response under the resonant frequency. At last, the curve of Seismometer frequency response is given.

  14. ACCELERATED PROCESSING OF SB4 AND PREPARATION FOR SB5 PROCESSING AT DWPF

    SciTech Connect

    Herman, C

    2008-12-01

    The Defense Waste Processing Facility (DWPF) initiated processing of Sludge Batch 4 (SB4) in May 2007. SB4 was the first DWPF sludge batch to contain significant quantities of HM or high Al sludge. Initial testing with SB4 simulants showed potential negative impacts to DWPF processing; therefore, Savannah River National Laboratory (SRNL) performed extensive testing in an attempt to optimize processing. SRNL's testing has resulted in the highest DWPF production rates since start-up. During SB4 processing, DWPF also began incorporating waste streams from the interim salt processing facilities to initiate coupled operations. While DWPF has been processing SB4, the Liquid Waste Organization (LWO) and the SRNL have been preparing Sludge Batch 5 (SB5). SB5 has undergone low-temperature aluminum dissolution to reduce the mass of sludge for vitrification and will contain a small fraction of Purex sludge. A high-level review of SB4 processing and the SB5 preparation studies will be provided.

  15. Successes and lessons learned: How to accelerate the base closure process

    SciTech Connect

    Larkin, V.C.; Stoll, R.

    1994-12-31

    Naval Station Puget Sound, Seattle, was nominated for closure by the Base Closure Commission in 1991 (BRAC II) and will be transferred in September of 1995. Historic activities have resulted in petroleum-related environmental issues. Unlike many bases being closed, the politically sensitive issues are not the economics of job losses. Because homeless housing is expected to be included in the selected reuse plan, the primary concerns of the public are reduced real estate values and public safety. In addition to a reuse plan adopted by the Seattle City Council, the Muckleshoot Indian tribe has also submitted an alternative reuse plan to the Navy. Acceleration methods described in this paper include methods for beginning the environmental impact statement (EIS) process before reuse plans are finalized; tracking development of engineering alternatives in parallel with environmental investigations; using field screening data to begin developing plans and specifications for remediation, instead of waiting 6 weeks for analytical results and data validation; using efficient communication techniques to facilitate accelerated review of technical documents by the BCT; expediting removal actions and performing ``cleanups incidental to investigation``; and effectively facilitating members of the Restoration Advisory Board with divergent points of view. This paper will describe acceleration methods that proved to be effective and methods that could be modified to be more effective at other sites.

  16. Physical processes at work in sub-30 fs, PW laser pulse-driven plasma accelerators: Towards GeV electron acceleration experiments at CILEX facility

    NASA Astrophysics Data System (ADS)

    Beck, A.; Kalmykov, S. Y.; Davoine, X.; Lifschitz, A.; Shadwick, B. A.; Malka, V.; Specka, A.

    2014-03-01

    Optimal regimes and physical processes at work are identified for the first round of laser wakefield acceleration experiments proposed at a future CILEX facility. The Apollon-10P CILEX laser, delivering fully compressed, near-PW-power pulses of sub-25 fs duration, is well suited for driving electron density wakes in the blowout regime in cm-length gas targets. Early destruction of the pulse (partly due to energy depletion) prevents electrons from reaching dephasing, limiting the energy gain to about 3 GeV. However, the optimal operating regimes, found with reduced and full three-dimensional particle-in-cell simulations, show high energy efficiency, with about 10% of incident pulse energy transferred to 3 GeV electron bunches with sub-5% energy spread, half-nC charge, and absolutely no low-energy background. This optimal acceleration occurs in 2 cm length plasmas of electron density below 1018 cm-3. Due to their high charge and low phase space volume, these multi-GeV bunches are tailor-made for staged acceleration planned in the framework of the CILEX project. The hallmarks of the optimal regime are electron self-injection at the early stage of laser pulse propagation, stable self-guiding of the pulse through the entire acceleration process, and no need for an external plasma channel. With the initial focal spot closely matched for the nonlinear self-guiding, the laser pulse stabilizes transversely within two Rayleigh lengths, preventing subsequent evolution of the accelerating bucket. This dynamics prevents continuous self-injection of background electrons, preserving low phase space volume of the bunch through the plasma. Near the end of propagation, an optical shock builds up in the pulse tail. This neither disrupts pulse propagation nor produces any noticeable low-energy background in the electron spectra, which is in striking contrast with most of existing GeV-scale acceleration experiments.

  17. Ground Test of the Urine Processing Assembly for Accelerations and Transfer Functions

    NASA Technical Reports Server (NTRS)

    Houston, Janice; Almond, Deborah F. (Technical Monitor)

    2001-01-01

    This viewgraph presentation gives an overview of the ground test of the urine processing assembly for accelerations and transfer functions. Details are given on the test setup, test data, data analysis, analytical results, and microgravity assessment. The conclusions of the tests include the following: (1) the single input/multiple output method is useful if the data is acquired by tri-axial accelerometers and inputs can be considered uncorrelated; (2) tying coherence with the matrix yields higher confidence in results; (3) the WRS#2 rack ORUs need to be isolated; (4) and future work includes a plan for characterizing performance of isolation materials.

  18. Turbulent Magnetohydrodynamic Acceleration Processes: Theory SSX Experiments and Connections to Space and Astrophysics

    SciTech Connect

    W Matthaeus; M Brown

    2006-07-15

    This is the final technical report for a funded program to provide theoretical support to the Swarthmore Spheromak Experiment. We examined mhd relaxation, reconnecton between two spheromaks, particle acceleration by these processes, and collisonless effects, e.g., Hall effect near the reconnection zone,. Throughout the project, applications to space plasma physics and astrophysics were included. Towards the end ofthe project we were examining a more fully turbulent relaxation associated with unconstrained dynamics in SSX. We employed experimental, spacecraft observations, analytical and numerical methods.

  19. Accelerated simulation of stochastic particle removal processes in particle-resolved aerosol models

    SciTech Connect

    Curtis, J.H.; Michelotti, M.D.; Riemer, N.; Heath, M.T.; West, M.

    2016-10-01

    Stochastic particle-resolved methods have proven useful for simulating multi-dimensional systems such as composition-resolved aerosol size distributions. While particle-resolved methods have substantial benefits for highly detailed simulations, these techniques suffer from high computational cost, motivating efforts to improve their algorithmic efficiency. Here we formulate an algorithm for accelerating particle removal processes by aggregating particles of similar size into bins. We present the Binned Algorithm for particle removal processes and analyze its performance with application to the atmospherically relevant process of aerosol dry deposition. We show that the Binned Algorithm can dramatically improve the efficiency of particle removals, particularly for low removal rates, and that computational cost is reduced without introducing additional error. In simulations of aerosol particle removal by dry deposition in atmospherically relevant conditions, we demonstrate about 50-times increase in algorithm efficiency.

  20. Large scale neural circuit mapping data analysis accelerated with the graphical processing unit (GPU)

    PubMed Central

    Shi, Yulin; Veidenbaum, Alexander V.; Nicolau, Alex; Xu, Xiangmin

    2014-01-01

    Background Modern neuroscience research demands computing power. Neural circuit mapping studies such as those using laser scanning photostimulation (LSPS) produce large amounts of data and require intensive computation for post-hoc processing and analysis. New Method Here we report on the design and implementation of a cost-effective desktop computer system for accelerated experimental data processing with recent GPU computing technology. A new version of Matlab software with GPU enabled functions is used to develop programs that run on Nvidia GPUs to harness their parallel computing power. Results We evaluated both the central processing unit (CPU) and GPU-enabled computational performance of our system in benchmark testing and practical applications. The experimental results show that the GPU-CPU co-processing of simulated data and actual LSPS experimental data clearly outperformed the multi-core CPU with up to a 22x speedup, depending on computational tasks. Further, we present a comparison of numerical accuracy between GPU and CPU computation to verify the precision of GPU computation. In addition, we show how GPUs can be effectively adapted to improve the performance of commercial image processing software such as Adobe Photoshop. Comparison with Existing Method(s) To our best knowledge, this is the first demonstration of GPU application in neural circuit mapping and electrophysiology-based data processing. Conclusions Together, GPU enabled computation enhances our ability to process large-scale data sets derived from neural circuit mapping studies, allowing for increased processing speeds while retaining data precision. PMID:25277633

  1. Spatiotemporal processing of linear acceleration: primary afferent and central vestibular neuron responses

    NASA Technical Reports Server (NTRS)

    Angelaki, D. E.; Dickman, J. D.

    2000-01-01

    Spatiotemporal convergence and two-dimensional (2-D) neural tuning have been proposed as a major neural mechanism in the signal processing of linear acceleration. To examine this hypothesis, we studied the firing properties of primary otolith afferents and central otolith neurons that respond exclusively to horizontal linear accelerations of the head (0.16-10 Hz) in alert rhesus monkeys. Unlike primary afferents, the majority of central otolith neurons exhibited 2-D spatial tuning to linear acceleration. As a result, central otolith dynamics vary as a function of movement direction. During movement along the maximum sensitivity direction, the dynamics of all central otolith neurons differed significantly from those observed for the primary afferent population. Specifically at low frequencies (acceleration. At least three different groups of central response dynamics were described according to the properties observed for motion along the maximum sensitivity direction. "High-pass" neurons exhibited increasing gains and phase values as a function of frequency. "Flat" neurons were characterized by relatively flat gains and constant phase lags (approximately 20-55 degrees ). A few neurons ("low-pass") were characterized by decreasing gain and phase as a function of frequency. The response dynamics of central otolith neurons suggest that the approximately 90 degrees phase lags observed at low frequencies are not the result of a neural integration but rather the effect of nonminimum phase behavior, which could arise at least partly through spatiotemporal convergence. Neither afferent nor central otolith neurons discriminated between gravitational and inertial components of linear acceleration. Thus response sensitivity was indistinguishable during 0.5-Hz pitch oscillations and fore-aft movements

  2. Accelerated rescaling of single Monte Carlo simulation runs with the Graphics Processing Unit (GPU).

    PubMed

    Yang, Owen; Choi, Bernard

    2013-01-01

    To interpret fiber-based and camera-based measurements of remitted light from biological tissues, researchers typically use analytical models, such as the diffusion approximation to light transport theory, or stochastic models, such as Monte Carlo modeling. To achieve rapid (ideally real-time) measurement of tissue optical properties, especially in clinical situations, there is a critical need to accelerate Monte Carlo simulation runs. In this manuscript, we report on our approach using the Graphics Processing Unit (GPU) to accelerate rescaling of single Monte Carlo runs to calculate rapidly diffuse reflectance values for different sets of tissue optical properties. We selected MATLAB to enable non-specialists in C and CUDA-based programming to use the generated open-source code. We developed a software package with four abstraction layers. To calculate a set of diffuse reflectance values from a simulated tissue with homogeneous optical properties, our rescaling GPU-based approach achieves a reduction in computation time of several orders of magnitude as compared to other GPU-based approaches. Specifically, our GPU-based approach generated a diffuse reflectance value in 0.08ms. The transfer time from CPU to GPU memory currently is a limiting factor with GPU-based calculations. However, for calculation of multiple diffuse reflectance values, our GPU-based approach still can lead to processing that is ~3400 times faster than other GPU-based approaches.

  3. Utilization of Integrated Process Control, Data Capture, and Data Analysis in Construction of Accelerator Systems

    SciTech Connect

    Bonnie Madre; Charles Reece; Joseph Ozelis; Valerie Bookwalter

    2003-05-12

    Jefferson Lab has developed a web-based system that integrates commercial database, data analysis, document archiving and retrieval, and user interface software, into a coherent knowledge management product (Pansophy). This product provides important tools for the successful pursuit of major projects such as accelerator system development and construction, by offering elements of process and procedure control, data capture and review, and data mining and analysis. After a period of initial development, Pansophy is now being used in Jefferson Lab's SNS superconducting linac construction effort, as a means for structuring and implementing the QA program, for process control and tracking, and for cryomodule test data capture and presentation/analysis. Development of Pansophy is continuing, in particular data queries and analysis functions that are the cornerstone of its utility.

  4. Arsenite exposure accelerates aging process regulated by the transcription factor DAF-16/FOXO in Caenorhabditis elegans.

    PubMed

    Yu, Chan-Wei; How, Chun Ming; Liao, Vivian Hsiu-Chuan

    2016-05-01

    Arsenic is a known human carcinogen and high levels of arsenic contamination in food, soils, water, and air are of toxicology concerns. Nowadays, arsenic is still a contaminant of emerging interest, yet the effects of arsenic on aging process have received little attention. In this study, we investigated the effects and the underlying mechanisms of chronic arsenite exposure on the aging process in Caenorhabditis elegans. The results showed that prolonged arsenite exposure caused significantly decreased lifespan compared to non-exposed ones. In addition, arsenite exposure (100 μM) caused significant changes of age-dependent biomarkers, including a decrease of defecation frequency, accumulations of intestinal lipofuscin and lipid peroxidation in an age-dependent manner in C. elegans. Further evidence revealed that intracellular reactive oxygen species (ROS) level was significantly increased in an age-dependent manner upon 100 μM arsenite exposure. Moreover, the mRNA levels of transcriptional makers of aging (hsp-16.1, hsp-16.49, and hsp-70) were increased in aged worms under arsenite exposure (100 μM). Finally, we showed that daf-16 mutant worms were more sensitive to arsenite exposure (100 μM) on lifespan and failed to induce the expression of its target gene sod-3 in aged daf-16 mutant under arsenite exposure (100 μM). Our study demonstrated that chronic arsenite exposure resulted in accelerated aging process in C. elegans. The overproduction of intracellular ROS and the transcription factor DAF-16/FOXO play roles in mediating the accelerated aging process by arsenite exposure in C. elegans. This study implicates a potential ecotoxicological and health risk of arsenic in the environment.

  5. Lipid volume fraction in atherosclerotic plaque phantoms classified under saline conditions by multispectral angioscopy at near-infrared wavelengths around 1200 nm.

    PubMed

    Matsui, Daichi; Ishii, Katsunori; Awazu, Kunio

    2016-05-01

    To identify high-risk atherosclerotic lesions, we require detailed information on the stability of atherosclerotic plaques. In this study, we quantitatively classified the lipid volume fractions in atherosclerotic plaque phantoms by a novel angioscope combined with near-infrared multispectral imaging. The multispectral angioscope was operated at peak absorption wavelengths of lipid in vulnerable plaques (1150, 1200, and 1300 nm) and at lower absorption wavelengths of water. The potential of the multispectral angioscope was demonstrated in atherosclerotic plaque phantoms containing 10-60 vol.% lipid and immersed in saline solution. The acquired multispectral data were processed by a spectral angle mapper algorithm, which enhanced the simulated plaque areas. Consequently, we classified the lipid volume fractions into five categories (0-5, 5-15, 15-30, 30-50, and 50-60 vol.%). Multispectral angioscopy at wavelengths around 1200 nm is a powerful tool for quantitatively evaluating the stability of atherosclerotic plaques based on the lipid volume fractions.

  6. Ion distributions in the vicinity of Mars: Signatures of heating and acceleration processes

    NASA Astrophysics Data System (ADS)

    Nilsson, H.; Stenberg, G.; Futaana, Y.; Holmström, M.; Barabash, S.; Lundin, R.; Edberg, N. J. T.; Fedorov, A.

    2012-02-01

    More than three years of data from the ASPERA-3 instrument on-board Mars Express has been used to compile average distribution functions of ions in and around the Mars induced magnetosphere. We present samples of average distribution functions, as well as average flux patterns based on the average distribution functions, all suitable for detailed comparison with models of the near-Mars space environment. The average heavy ion distributions close to the planet form thermal populations with a temperature of 3 to 10 eV. The distribution functions in the tail consist of two populations, one cold which is an extension of the low altitude population, and one accelerated population of ionospheric origin ions. All significant fluxes of heavy ions in the tail are tailward. The heavy ions in the magnetosheath form a plume with the flow aligned with the bow shock, and a more radial flow direction than the solar wind origin flow. Summarizing the escape processes, ionospheric ions are heated close to the planet, presumably through wave-particle interaction. These heated populations are accelerated in the tailward direction in a restricted region. Another significant escape path is through the magnetosheath. A part of the ionospheric population is likely accelerated in the radial direction, out into the magnetosheath, although pick up of an oxygen exosphere may also be a viable source for this escape. Increased energy input from the solar wind during CIR events appear to mainly increase the number flux of escaping particles, the average energy of the escaping particles is not strongly affected. Heavy ions on the dayside may precipitate and cause sputtering of the atmosphere, though fluxes are likely lower than 0.4 × 1023 s-1.

  7. 12- and 15-lipoxygenases in human carotid atherosclerotic lesions: Associations with cerebrovascular symptoms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lipoxygenase (ALOX) enzymes are implicated in both pro- and anti-atherogenic processes. The aim of this study was to investigate mRNA expression of 12- and 15-lipoxygenases (ALOX12, ALOX12B, ALOX15, ALOX15B) and the atypical ALOXE3 in human carotid atherosclerotic lesions, in relation to cerebrovasc...

  8. Inhibiting macrophage proliferation suppresses atherosclerotic plaque inflammation.

    PubMed

    Tang, Jun; Lobatto, Mark E; Hassing, Laurien; van der Staay, Susanne; van Rijs, Sarian M; Calcagno, Claudia; Braza, Mounia S; Baxter, Samantha; Fay, Francois; Sanchez-Gaytan, Brenda L; Duivenvoorden, Raphaël; Sager, Hendrik; Astudillo, Yaritzy M; Leong, Wei; Ramachandran, Sarayu; Storm, Gert; Pérez-Medina, Carlos; Reiner, Thomas; Cormode, David P; Strijkers, Gustav J; Stroes, Erik S G; Swirski, Filip K; Nahrendorf, Matthias; Fisher, Edward A; Fayad, Zahi A; Mulder, Willem J M

    2015-04-01

    Inflammation drives atherosclerotic plaque progression and rupture, and is a compelling therapeutic target. Consequently, attenuating inflammation by reducing local macrophage accumulation is an appealing approach. This can potentially be accomplished by either blocking blood monocyte recruitment to the plaque or increasing macrophage apoptosis and emigration. Because macrophage proliferation was recently shown to dominate macrophage accumulation in advanced plaques, locally inhibiting macrophage proliferation may reduce plaque inflammation and produce long-term therapeutic benefits. To test this hypothesis, we used nanoparticle-based delivery of simvastatin to inhibit plaque macrophage proliferation in apolipoprotein E deficient mice (Apoe(-/-) ) with advanced atherosclerotic plaques. This resulted in rapid reduction of plaque inflammation and favorable phenotype remodeling. We then combined this short-term nanoparticle intervention with an eight-week oral statin treatment, and this regimen rapidly reduced and continuously suppressed plaque inflammation. Our results demonstrate that pharmacologically inhibiting local macrophage proliferation can effectively treat inflammation in atherosclerosis.

  9. Inhibiting macrophage proliferation suppresses atherosclerotic plaque inflammation

    PubMed Central

    Tang, Jun; Lobatto, Mark E.; Hassing, Laurien; van der Staay, Susanne; van Rijs, Sarian M.; Calcagno, Claudia; Braza, Mounia S.; Baxter, Samantha; Fay, Francois; Sanchez-Gaytan, Brenda L.; Duivenvoorden, Raphaël; Sager, Hendrik B.; Astudillo, Yaritzy M.; Leong, Wei; Ramachandran, Sarayu; Storm, Gert; Pérez-Medina, Carlos; Reiner, Thomas; Cormode, David P.; Strijkers, Gustav J.; Stroes, Erik S. G.; Swirski, Filip K.; Nahrendorf, Matthias; Fisher, Edward A.; Fayad, Zahi A.; Mulder, Willem J. M.

    2015-01-01

    Inflammation drives atherosclerotic plaque progression and rupture, and is a compelling therapeutic target. Consequently, attenuating inflammation by reducing local macrophage accumulation is an appealing approach. This can potentially be accomplished by either blocking blood monocyte recruitment to the plaque or increasing macrophage apoptosis and emigration. Because macrophage proliferation was recently shown to dominate macrophage accumulation in advanced plaques, locally inhibiting macrophage proliferation may reduce plaque inflammation and produce long-term therapeutic benefits. To test this hypothesis, we used nanoparticle-based delivery of simvastatin to inhibit plaque macrophage proliferation in apolipoprotein E–deficient mice (Apoe−/−) with advanced atherosclerotic plaques. This resulted in the rapid reduction of plaque inflammation and favorable phenotype remodeling. We then combined this short-term nanoparticle intervention with an 8-week oral statin treatment, and this regimen rapidly reduced and continuously suppressed plaque inflammation. Our results demonstrate that pharmacologically inhibiting local macrophage proliferation can effectively treat inflammation in atherosclerosis. PMID:26295063

  10. Accelerating image reconstruction in three-dimensional optoacoustic tomography on graphics processing units

    PubMed Central

    Wang, Kun; Huang, Chao; Kao, Yu-Jiun; Chou, Cheng-Ying; Oraevsky, Alexander A.; Anastasio, Mark A.

    2013-01-01

    Purpose: Optoacoustic tomography (OAT) is inherently a three-dimensional (3D) inverse problem. However, most studies of OAT image reconstruction still employ two-dimensional imaging models. One important reason is because 3D image reconstruction is computationally burdensome. The aim of this work is to accelerate existing image reconstruction algorithms for 3D OAT by use of parallel programming techniques. Methods: Parallelization strategies are proposed to accelerate a filtered backprojection (FBP) algorithm and two different pairs of projection/backprojection operations that correspond to two different numerical imaging models. The algorithms are designed to fully exploit the parallel computing power of graphics processing units (GPUs). In order to evaluate the parallelization strategies for the projection/backprojection pairs, an iterative image reconstruction algorithm is implemented. Computer simulation and experimental studies are conducted to investigate the computational efficiency and numerical accuracy of the developed algorithms. Results: The GPU implementations improve the computational efficiency by factors of 1000, 125, and 250 for the FBP algorithm and the two pairs of projection/backprojection operators, respectively. Accurate images are reconstructed by use of the FBP and iterative image reconstruction algorithms from both computer-simulated and experimental data. Conclusions: Parallelization strategies for 3D OAT image reconstruction are proposed for the first time. These GPU-based implementations significantly reduce the computational time for 3D image reconstruction, complementing our earlier work on 3D OAT iterative image reconstruction. PMID:23387778

  11. Investigation on the internal acceleration process of the outer radiation belt using the particle filter

    NASA Astrophysics Data System (ADS)

    Toyama, H.; Miyoshi, Y.; Ueno, G.; Koshiishi, H.; Matsumoto, H.; Shiokawa, K.

    2013-12-01

    It is known that high energy electrons in the radiation belts often cause satellite anomalies and malfunctions. Thus, a forecast of the time variation of the energetic electrons is necessary to protect satellites in the radiation belts. Time variations of the radiation belt electrons have been modeled with the Fokker-Plank equation. Performance of the forecast using the Fokker-Planck equation depends on the parameters used in the model, so that improvement of the parameters is important for the space weather forecast. We performed data assimilation using the particle filter by a code which was developed by Miyoshi et al.[2006]. We prepare 1000 particles used for the calculation. In this study, phase space density, the diffusion coefficient, and wave amplitude, and the source amplitude of the internal acceleration compose the state vector. The observation vector consists of the differential flux measured by the Tsubasa satellite. We also apply the particle smoother to estimate the smoothed distribution. While there were several discrepancies between the simulation without the data assimilation and the observations, the data assimilation improves the simulation result, and captures the typical flux variations of the outer belt during magnetic storms. We also discuss the internal acceleration process on the basis of the source amplitude estimated through the data assimilation.

  12. Graphics processing unit (GPU)-accelerated particle filter framework for positron emission tomography image reconstruction.

    PubMed

    Yu, Fengchao; Liu, Huafeng; Hu, Zhenghui; Shi, Pengcheng

    2012-04-01

    As a consequence of the random nature of photon emissions and detections, the data collected by a positron emission tomography (PET) imaging system can be shown to be Poisson distributed. Meanwhile, there have been considerable efforts within the tracer kinetic modeling communities aimed at establishing the relationship between the PET data and physiological parameters that affect the uptake and metabolism of the tracer. Both statistical and physiological models are important to PET reconstruction. The majority of previous efforts are based on simplified, nonphysical mathematical expression, such as Poisson modeling of the measured data, which is, on the whole, completed without consideration of the underlying physiology. In this paper, we proposed a graphics processing unit (GPU)-accelerated reconstruction strategy that can take both statistical model and physiological model into consideration with the aid of state-space evolution equations. The proposed strategy formulates the organ activity distribution through tracer kinetics models and the photon-counting measurements through observation equations, thus making it possible to unify these two constraints into a general framework. In order to accelerate reconstruction, GPU-based parallel computing is introduced. Experiments of Zubal-thorax-phantom data, Monte Carlo simulated phantom data, and real phantom data show the power of the method. Furthermore, thanks to the computing power of the GPU, the reconstruction time is practical for clinical application.

  13. GAMER: A GRAPHIC PROCESSING UNIT ACCELERATED ADAPTIVE-MESH-REFINEMENT CODE FOR ASTROPHYSICS

    SciTech Connect

    Schive, H.-Y.; Tsai, Y.-C.; Chiueh Tzihong

    2010-02-01

    We present the newly developed code, GPU-accelerated Adaptive-MEsh-Refinement code (GAMER), which adopts a novel approach in improving the performance of adaptive-mesh-refinement (AMR) astrophysical simulations by a large factor with the use of the graphic processing unit (GPU). The AMR implementation is based on a hierarchy of grid patches with an oct-tree data structure. We adopt a three-dimensional relaxing total variation diminishing scheme for the hydrodynamic solver and a multi-level relaxation scheme for the Poisson solver. Both solvers have been implemented in GPU, by which hundreds of patches can be advanced in parallel. The computational overhead associated with the data transfer between the CPU and GPU is carefully reduced by utilizing the capability of asynchronous memory copies in GPU, and the computing time of the ghost-zone values for each patch is diminished by overlapping it with the GPU computations. We demonstrate the accuracy of the code by performing several standard test problems in astrophysics. GAMER is a parallel code that can be run in a multi-GPU cluster system. We measure the performance of the code by performing purely baryonic cosmological simulations in different hardware implementations, in which detailed timing analyses provide comparison between the computations with and without GPU(s) acceleration. Maximum speed-up factors of 12.19 and 10.47 are demonstrated using one GPU with 4096{sup 3} effective resolution and 16 GPUs with 8192{sup 3} effective resolution, respectively.

  14. Accelerated Molecular Dynamics Simulations with the AMOEBA Polarizable Force Field on Graphics Processing Units.

    PubMed

    Lindert, Steffen; Bucher, Denis; Eastman, Peter; Pande, Vijay; McCammon, J Andrew

    2013-11-12

    The accelerated molecular dynamics (aMD) method has recently been shown to enhance the sampling of biomolecules in molecular dynamics (MD) simulations, often by several orders of magnitude. Here, we describe an implementation of the aMD method for the OpenMM application layer that takes full advantage of graphics processing units (GPUs) computing. The aMD method is shown to work in combination with the AMOEBA polarizable force field (AMOEBA-aMD), allowing the simulation of long time-scale events with a polarizable force field. Benchmarks are provided to show that the AMOEBA-aMD method is efficiently implemented and produces accurate results in its standard parametrization. For the BPTI protein, we demonstrate that the protein structure described with AMOEBA remains stable even on the extended time scales accessed at high levels of accelerations. For the DNA repair metalloenzyme endonuclease IV, we show that the use of the AMOEBA force field is a significant improvement over fixed charged models for describing the enzyme active-site. The new AMOEBA-aMD method is publicly available (http://wiki.simtk.org/openmm/VirtualRepository) and promises to be interesting for studying complex systems that can benefit from both the use of a polarizable force field and enhanced sampling.

  15. Accelerated evolution after gene duplication: a time-dependent process affecting just one copy.

    PubMed

    Pegueroles, Cinta; Laurie, Steve; Albà, M Mar

    2013-08-01

    Gene duplication is widely regarded as a major mechanism modeling genome evolution and function. However, the mechanisms that drive the evolution of the two, initially redundant, gene copies are still ill defined. Many gene duplicates experience evolutionary rate acceleration, but the relative contribution of positive selection and random drift to the retention and subsequent evolution of gene duplicates, and for how long the molecular clock may be distorted by these processes, remains unclear. Focusing on rodent genes that duplicated before and after the mouse and rat split, we find significantly increased sequence divergence after duplication in only one of the copies, which in nearly all cases corresponds to the novel daughter copy, independent of the mechanism of duplication. We observe that the evolutionary rate of the accelerated copy, measured as the ratio of nonsynonymous to synonymous substitutions, is on average 5-fold higher in the period spanning 4-12 My after the duplication than it was before the duplication. This increase can be explained, at least in part, by the action of positive selection according to the results of the maximum likelihood-based branch-site test. Subsequently, the rate decelerates until purifying selection completely returns to preduplication levels. Reversion to the original rates has already been accomplished 40.5 My after the duplication event, corresponding to a genetic distance of about 0.28 synonymous substitutions per site. Differences in tissue gene expression patterns parallel those of substitution rates, reinforcing the role of neofunctionalization in explaining the evolution of young gene duplicates.

  16. Quantitative evaluation of lipid concentration in atherosclerotic plaque phantom by near-infrared multispectral angioscope at wavelengths around 1200 nm

    NASA Astrophysics Data System (ADS)

    Matsui, Daichi; Ishii, Katsunori; Awazu, Kunio

    2015-07-01

    Atherosclerosis is a primary cause of critical ischemic diseases like heart infarction or stroke. A method that can provide detailed information about the stability of atherosclerotic plaques is required. We focused on spectroscopic techniques that could evaluate the chemical composition of lipid in plaques. A novel angioscope using multispectral imaging at wavelengths around 1200 nm for quantitative evaluation of atherosclerotic plaques was developed. The angioscope consists of a halogen lamp, an indium gallium arsenide (InGaAs) camera, 3 optical band pass filters transmitting wavelengths of 1150, 1200, and 1300 nm, an image fiber having 0.7 mm outer diameter, and an irradiation fiber which consists of 7 multimode fibers. Atherosclerotic plaque phantoms with 100, 60, 20 vol.% of lipid were prepared and measured by the multispectral angioscope. The acquired datasets were processed by spectral angle mapper (SAM) method. As a result, simulated plaque areas in atherosclerotic plaque phantoms that could not be detected by an angioscopic visible image could be clearly enhanced. In addition, quantitative evaluation of atherosclerotic plaque phantoms based on the lipid volume fractions was performed up to 20 vol.%. These results show the potential of a multispectral angioscope at wavelengths around 1200 nm for quantitative evaluation of the stability of atherosclerotic plaques.

  17. High-Speed Digital Signal Processing Method for Detection of Repeating Earthquakes Using GPGPU-Acceleration

    NASA Astrophysics Data System (ADS)

    Kawakami, Taiki; Okubo, Kan; Uchida, Naoki; Takeuchi, Nobunao; Matsuzawa, Toru

    2013-04-01

    Repeating earthquakes are occurring on the similar asperity at the plate boundary. These earthquakes have an important property; the seismic waveforms observed at the identical observation site are very similar regardless of their occurrence time. The slip histories of repeating earthquakes could reveal the existence of asperities: The Analysis of repeating earthquakes can detect the characteristics of the asperities and realize the temporal and spatial monitoring of the slip in the plate boundary. Moreover, we are expecting the medium-term predictions of earthquake at the plate boundary by means of analysis of repeating earthquakes. Although the previous works mostly clarified the existence of asperity and repeating earthquake, and relationship between asperity and quasi-static slip area, the stable and robust method for automatic detection of repeating earthquakes has not been established yet. Furthermore, in order to process the enormous data (so-called big data) the speedup of the signal processing is an important issue. Recently, GPU (Graphic Processing Unit) is used as an acceleration tool for the signal processing in various study fields. This movement is called GPGPU (General Purpose computing on GPUs). In the last few years the performance of GPU keeps on improving rapidly. That is, a PC (personal computer) with GPUs might be a personal supercomputer. GPU computing gives us the high-performance computing environment at a lower cost than before. Therefore, the use of GPUs contributes to a significant reduction of the execution time in signal processing of the huge seismic data. In this study, first, we applied the band-limited Fourier phase correlation as a fast method of detecting repeating earthquake. This method utilizes only band-limited phase information and yields the correlation values between two seismic signals. Secondly, we employ coherence function using three orthogonal components (East-West, North-South, and Up-Down) of seismic data as a

  18. Using a commercial graphical processing unit and the CUDA programming language to accelerate scientific image processing applications

    NASA Astrophysics Data System (ADS)

    Broussard, Randy P.; Ives, Robert W.

    2011-01-01

    In the past two years the processing power of video graphics cards has quadrupled and is approaching super computer levels. State-of-the-art graphical processing units (GPU) boast of theoretical computational performance in the range of 1.5 trillion floating point operations per second (1.5 Teraflops). This processing power is readily accessible to the scientific community at a relatively small cost. High level programming languages are now available that give access to the internal architecture of the graphics card allowing greater algorithm optimization. This research takes memory access expensive portions of an image-based iris identification algorithm and hosts it on a GPU using the C++ compatible CUDA language. The selected segmentation algorithm uses basic image processing techniques such as image inversion, value squaring, thresholding, dilation, erosion and memory/computationally intensive calculations such as the circular Hough transform. Portions of the iris segmentation algorithm were accelerated by a factor of 77 over the 2008 GPU results. Some parts of the algorithm ran at speeds that were over 1600 times faster than their CPU counterparts. Strengths and limitations of the GPU Single Instruction Multiple Data architecture are discussed. Memory access times, instruction execution times, programming details and code samples are presented as part of the research.

  19. Elevated-temperature-induced acceleration of PACT clearing process of mouse brain tissue

    NASA Astrophysics Data System (ADS)

    Yu, Tingting; Qi, Yisong; Zhu, Jingtan; Xu, Jianyi; Gong, Hui; Luo, Qingming; Zhu, Dan

    2017-01-01

    Tissue optical clearing technique shows a great potential for neural imaging with high resolution, especially for connectomics in brain. The passive clarity technique (PACT) is a relative simple clearing method based on incubation, which has a great advantage on tissue transparency, fluorescence preservation and immunostaining compatibility for imaging tissue blocks. However, this method suffers from long processing time. Previous studies indicated that increasing temperature can speed up the clearing. In this work, we aim to systematacially and quantitatively study this influence based on PACT with graded increase of temperatures. We investigated the process of optical clearing of brain tissue block at different temperatures, and found that elevated temperature could accelerate the clearing process and also had influence on the fluorescence intensity. By balancing the advantages with drawbacks, we conclude that 42–47 °C is an alternative temperature range for PACT, which can not only produce faster clearing process, but also retain the original advantages of PACT by preserving endogenous fluorescence well, achieving fine morphology maintenance and immunostaining compatibility.

  20. Elevated-temperature-induced acceleration of PACT clearing process of mouse brain tissue

    PubMed Central

    Yu, Tingting; Qi, Yisong; Zhu, Jingtan; Xu, Jianyi; Gong, Hui; Luo, Qingming; Zhu, Dan

    2017-01-01

    Tissue optical clearing technique shows a great potential for neural imaging with high resolution, especially for connectomics in brain. The passive clarity technique (PACT) is a relative simple clearing method based on incubation, which has a great advantage on tissue transparency, fluorescence preservation and immunostaining compatibility for imaging tissue blocks. However, this method suffers from long processing time. Previous studies indicated that increasing temperature can speed up the clearing. In this work, we aim to systematacially and quantitatively study this influence based on PACT with graded increase of temperatures. We investigated the process of optical clearing of brain tissue block at different temperatures, and found that elevated temperature could accelerate the clearing process and also had influence on the fluorescence intensity. By balancing the advantages with drawbacks, we conclude that 42–47 °C is an alternative temperature range for PACT, which can not only produce faster clearing process, but also retain the original advantages of PACT by preserving endogenous fluorescence well, achieving fine morphology maintenance and immunostaining compatibility. PMID:28139694

  1. Image processing and computer controls for video profile diagnostic system in the ground test accelerator (GTA)

    SciTech Connect

    Wright, R.M.; Zander, M.E.; Brown, S.K.; Sandoval, D.P.; Gilpatrick, J.D.; Gibson, H.E.

    1992-09-01

    This paper describes the application of video image processing to beam profile measurements on the Ground Test Accelerator (GTA). A diagnostic was needed to measure beam profiles in the intermediate matching section (IMS) between the radio-frequency quadrupole (RFQ) and the drift tube linac (DTL). Beam profiles are measured by injecting puffs of gas into the beam. The light emitted from the beam-gas interaction is captured and processed by a video image processing system, generating the beam profile data. A general purpose, modular and flexible video image processing system, imagetool, was used for the GTA image profile measurement. The development of both software and hardware for imagetool and its integration with the GTA control system (GTACS) will be discussed. The software includes specialized algorithms for analyzing data and calibrating the system. The underlying design philosophy of imagetool was tested by the experience of building and using the system, pointing the way for future improvements. The current status of the system will be illustrated by samples of experimental data.

  2. Image processing and computer controls for video profile diagnostic system in the ground test accelerator (GTA)

    SciTech Connect

    Wright, R.M.; Zander, M.E.; Brown, S.K.; Sandoval, D.P.; Gilpatrick, J.D.; Gibson, H.E.

    1992-01-01

    This paper describes the application of video image processing to beam profile measurements on the Ground Test Accelerator (GTA). A diagnostic was needed to measure beam profiles in the intermediate matching section (IMS) between the radio-frequency quadrupole (RFQ) and the drift tube linac (DTL). Beam profiles are measured by injecting puffs of gas into the beam. The light emitted from the beam-gas interaction is captured and processed by a video image processing system, generating the beam profile data. A general purpose, modular and flexible video image processing system, imagetool, was used for the GTA image profile measurement. The development of both software and hardware for imagetool and its integration with the GTA control system (GTACS) will be discussed. The software includes specialized algorithms for analyzing data and calibrating the system. The underlying design philosophy of imagetool was tested by the experience of building and using the system, pointing the way for future improvements. The current status of the system will be illustrated by samples of experimental data.

  3. Stochastic Modeling and Analysis of Multiple Nonlinear Accelerated Degradation Processes through Information Fusion

    PubMed Central

    Sun, Fuqiang; Liu, Le; Li, Xiaoyang; Liao, Haitao

    2016-01-01

    Accelerated degradation testing (ADT) is an efficient technique for evaluating the lifetime of a highly reliable product whose underlying failure process may be traced by the degradation of the product’s performance parameters with time. However, most research on ADT mainly focuses on a single performance parameter. In reality, the performance of a modern product is usually characterized by multiple parameters, and the degradation paths are usually nonlinear. To address such problems, this paper develops a new s-dependent nonlinear ADT model for products with multiple performance parameters using a general Wiener process and copulas. The general Wiener process models the nonlinear ADT data, and the dependency among different degradation measures is analyzed using the copula method. An engineering case study on a tuner’s ADT data is conducted to demonstrate the effectiveness of the proposed method. The results illustrate that the proposed method is quite effective in estimating the lifetime of a product with s-dependent performance parameters. PMID:27509499

  4. Processing of radioactive waste by the use of low energy ({le} 100 MeV) charged particle accelerators. Optimization problems

    SciTech Connect

    Mushnikov, V.N.; Ozhigov, L.S.; Khizhnyak, N.A.

    1993-12-31

    The radiation processing of long-lived radiotoxic elements is based on transmutation reactions under the action of various particles and energies. Among the different particle sources the most promising is the proton accelerator. The present work studied the process of radiation deactivation in the stationary proton flux as functions of their flux density and energy. The Bateman-Robinson differential equations were solved.

  5. Vibrotactile masking experiments reveal accelerated somatosensory processing in congenitally blind braille readers.

    PubMed

    Bhattacharjee, Arindam; Ye, Amanda J; Lisak, Joy A; Vargas, Maria G; Goldreich, Daniel

    2010-10-27

    Braille reading is a demanding task that requires the identification of rapidly varying tactile patterns. During proficient reading, neighboring characters impact the fingertip at ∼100 ms intervals, and adjacent raised dots within a character at 50 ms intervals. Because the brain requires time to interpret afferent sensorineural activity, among other reasons, tactile stimuli separated by such short temporal intervals pose a challenge to perception. How, then, do proficient Braille readers successfully interpret inputs arising from their fingertips at such rapid rates? We hypothesized that somatosensory perceptual consolidation occurs more rapidly in proficient Braille readers. If so, Braille readers should outperform sighted participants on masking tasks, which demand rapid perceptual processing, but would not necessarily outperform the sighted on tests of simple vibrotactile sensitivity. To investigate, we conducted two-interval forced-choice vibrotactile detection, amplitude discrimination, and masking tasks on the index fingertips of 89 sighted and 57 profoundly blind humans. Sighted and blind participants had similar unmasked detection (25 ms target tap) and amplitude discrimination (compared with 100 μm reference tap) thresholds, but congenitally blind Braille readers, the fastest readers among the blind participants, exhibited significantly less masking than the sighted (masker, 50 Hz, 50 μm; target-masker delays, ±50 and ±100 ms). Indeed, Braille reading speed correlated significantly and specifically with masking task performance, and in particular with the backward masking decay time constant. We conclude that vibrotactile sensitivity is unchanged but that perceptual processing is accelerated in congenitally blind Braille readers.

  6. Incipient fault detection and identification in process systems using accelerating neural network learning

    SciTech Connect

    Parlos, A.G.; Muthusami, J.; Atiya, A.F. . Dept. of Nuclear Engineering)

    1994-02-01

    The objective of this paper is to present the development and numerical testing of a robust fault detection and identification (FDI) system using artificial neural networks (ANNs), for incipient (slowly developing) faults occurring in process systems. The challenge in using ANNs in FDI systems arises because of one's desire to detect faults of varying severity, faults from noisy sensors, and multiple simultaneous faults. To address these issues, it becomes essential to have a learning algorithm that ensures quick convergence to a high level of accuracy. A recently developed accelerated learning algorithm, namely a form of an adaptive back propagation (ABP) algorithm, is used for this purpose. The ABP algorithm is used for the development of an FDI system for a process composed of a direct current motor, a centrifugal pump, and the associated piping system. Simulation studies indicate that the FDI system has significantly high sensitivity to incipient fault severity, while exhibiting insensitivity to sensor noise. For multiple simultaneous faults, the FDI system detects the fault with the predominant signature. The major limitation of the developed FDI system is encountered when it is subjected to simultaneous faults with similar signatures. During such faults, the inherent limitation of pattern-recognition-based FDI methods becomes apparent. Thus, alternate, more sophisticated FDI methods become necessary to address such problems. Even though the effectiveness of pattern-recognition-based FDI methods using ANNs has been demonstrated, further testing using real-world data is necessary.

  7. Detailed Modeling of Physical Processes in Electron Sources for Accelerator Applications

    NASA Astrophysics Data System (ADS)

    Chubenko, Oksana; Afanasev, Andrei

    2017-01-01

    At present, electron sources are essential in a wide range of applications - from common technical use to exploring the nature of matter. Depending on the application requirements, different methods and materials are used to generate electrons. State-of-the-art accelerator applications set a number of often-conflicting requirements for electron sources (e.g., quantum efficiency vs. polarization, current density vs. lifetime, etc). Development of advanced electron sources includes modeling and design of cathodes, material growth, fabrication of cathodes, and cathode testing. The detailed simulation and modeling of physical processes is required in order to shed light on the exact mechanisms of electron emission and to develop new-generation electron sources with optimized efficiency. The purpose of the present work is to study physical processes in advanced electron sources and develop scientific tools, which could be used to predict electron emission from novel nano-structured materials. In particular, the area of interest includes bulk/superlattice gallium arsenide (bulk/SL GaAs) photo-emitters and nitrogen-incorporated ultrananocrystalline diamond ((N)UNCD) photo/field-emitters. Work supported by The George Washington University and Euclid TechLabs LLC.

  8. Graphics Processing Unit (GPU) Acceleration of the Goddard Earth Observing System Atmospheric Model

    NASA Technical Reports Server (NTRS)

    Putnam, Williama

    2011-01-01

    The Goddard Earth Observing System 5 (GEOS-5) is the atmospheric model used by the Global Modeling and Assimilation Office (GMAO) for a variety of applications, from long-term climate prediction at relatively coarse resolution, to data assimilation and numerical weather prediction, to very high-resolution cloud-resolving simulations. GEOS-5 is being ported to a graphics processing unit (GPU) cluster at the NASA Center for Climate Simulation (NCCS). By utilizing GPU co-processor technology, we expect to increase the throughput of GEOS-5 by at least an order of magnitude, and accelerate the process of scientific exploration across all scales of global modeling, including: The large-scale, high-end application of non-hydrostatic, global, cloud-resolving modeling at 10- to I-kilometer (km) global resolutions Intermediate-resolution seasonal climate and weather prediction at 50- to 25-km on small clusters of GPUs Long-range, coarse-resolution climate modeling, enabled on a small box of GPUs for the individual researcher After being ported to the GPU cluster, the primary physics components and the dynamical core of GEOS-5 have demonstrated a potential speedup of 15-40 times over conventional processor cores. Performance improvements of this magnitude reduce the required scalability of 1-km, global, cloud-resolving models from an unfathomable 6 million cores to an attainable 200,000 GPU-enabled cores.

  9. Generalized Temporal Acceleration Scheme for Kinetic Monte Carlo Simulations of Surface Catalytic Processes by Scaling the Rates of Fast Reactions.

    PubMed

    Dybeck, Eric Christopher; Plaisance, Craig Patrick; Neurock, Matthew

    2017-02-14

    A novel algorithm has been developed to achieve temporal acceleration during kinetic Monte Carlo (KMC) simulations of surface catalytic processes. This algorithm allows for the direct simulation of reaction networks containing kinetic processes occurring on vastly disparate timescales which computationally overburden standard KMC methods. Previously developed methods for temporal acceleration in KMC have been designed for specific systems and often require a priori information from the user such as identifying the fast and slow processes. In the approach presented herein, quasi-equilibrated processes are identified automatically based on previous executions of the forward and reverse reactions. Temporal acceleration is achieved by automatically scaling the intrinsic rate constants of the quasi-equilibrated processes, bringing their rates closer to the timescales of the slow kinetically relevant non-equilibrated processes. All reactions are still simulated directly, although with modified rate constants. Abrupt changes in the underlying dynamics of the reaction network are identified during the simulation and the reaction rate constants are rescaled accordingly. The algorithm has been utilized here to model the Fischer-Tropsch synthesis reaction over ruthenium nanoparticles. This reaction network has multiple timescale-disparate processes which would be intractable to simulate without the aid of temporal acceleration. The accelerated simulations are found to give reaction rates and selectivities indistinguishable from those calculated by an equivalent mean-field kinetic model. The computational savings of the algorithm can span many orders of magnitude in realistic systems and the computational cost is not limited by the magnitude of the timescale disparity in the system processes. Furthermore, the algorithm has been designed in a generic fashion and can easily be applied to other surface catalytic processes of interest.

  10. Differentiation of Vascular Stem Cells Contributes to Ectopic Calcification of Atherosclerotic Plaque.

    PubMed

    Leszczynska, Aleksandra; O'Doherty, Aideen; Farrell, Eric; Pindjakova, Jana; O'Brien, Fergal J; O'Brien, Timothy; Barry, Frank; Murphy, Mary

    2016-04-01

    The cellular and molecular basis of vascular calcification (VC) in atherosclerosis is not fully understood. Here, we investigate role of resident/circulating progenitor cells in VC and contribution of inflammatory plaque environment to this process. Vessel-derived stem/progenitor cells (VSCs) and mesenchymal stem cells (MSCs) isolated from atherosclerotic ApoE(-/-) mice showed significantly more in vitro osteogenesis and chondrogenesis than cells generated from control C57BL/6 mice. To assess their ability to form bone in vivo, cells were primed chondrogenically or cultured in control medium on collagen glycosaminoglycan scaffolds in vitro prior to subcutaneous implantation in ApoE(-/-) and C57BL/6 mice using a crossover study design. Atherosclerotic ApoE(-/-) MSCs and VSCs formed bone when implanted in C57BL/6 mice. In ApoE(-/-) mice, these cells generated more mature bone than C57BL/6 cells. The atherosclerotic in vivo environment alone promoted bone formation by implanted C57BL/6 cells. Un-primed C57BL/6 VSCs were unable to form bone in either mouse strain. Treatment of ApoE(-/-) VSC chondrogenic cultures with interleukin (IL)-6 resulted in significantly increased glycosaminoglycan deposition and expression of characteristic chondrogenic genes at 21 days. In conclusion, resident vascular cells from atherosclerotic environment respond to the inflammatory milieu and undergo calcification. IL-6 may have a role in aberrant differentiation of VSCs contributing to vascular calcification in atherosclerosis.

  11. Pulsatile Flow Studies in Atherosclerotic Carotid Bifurcations

    NASA Astrophysics Data System (ADS)

    Bale-Glickman, Jocelyn; Selby, Kathy; Saloner, David; Savas, Omer

    2001-11-01

    Particle image velocimetry and flow visualization techniques are used to study flows in models of atherosclerotic carotid bifurcations. The flow models exactly replicate the interior geometry of plaque excised from patients. The input flows are physiological wave forms derived from Doppler Ultrasound scans done on patients before surgery. The systolic and diastolic Reynolds numbers are 300 and 900. The complex internal geometry of the diseased artery combined with the pulsatile input flow results in exceedingly complex flow patterns. These flow patterns include internal jets, three-dimensional shear layers, stagnation lines, and multiple recirculation and separation regions. The physiological input flows are compared to flows when the wave form is sinusoidal.

  12. Endovascular revascularization for aortoiliac atherosclerotic disease

    PubMed Central

    Aggarwal, Vikas; Waldo, Stephen W; Armstrong, Ehrin J

    2016-01-01

    Atherosclerotic iliac artery disease is increasingly being treated with endovascular techniques. A number of new stent technologies can be utilized with high long-term patency, including self-expanding stents, balloon-expandable stents, and covered stents, but comparative data on these stent types and in more complex lesions are lacking. This article provides a review of currently available iliac stent technologies, as well as complex procedural aspects of iliac artery interventions, including approaches to the treatment of iliac bifurcation disease, long segment occlusions, choice of stent type, and treatment of iliac artery in-stent restenosis. PMID:27099509

  13. Atherosclerotic renal artery stenosis: Current status

    PubMed Central

    Kwon, Soon Hyo; Lerman, Lilach O.

    2014-01-01

    Atherosclerotic renal artery stenosis (ARAS) remains a major cause of secondary hypertension and renal failure. Randomized, prospective trials show that medical treatment should constitute the main therapeutic approach in ARAS. Regardless of intensive treatment and adequate blood pressure control, however, renal and extra-renal complications are not uncommon. Yet, the precise mechanisms, accurate detection, and optimal treatment in ARAS remain elusive. Strategies oriented to early detection and targeting these pathogenic pathways might prevent development of clinical endpoints. Here, we review the results of recent clinical trials, current understanding of the pathogenic mechanisms, novel imaging techniques to assess renal damage in ARAS, and treatment options. PMID:25908472

  14. Bisphenol A exposure accelerated the aging process in the nematode Caenorhabditis elegans.

    PubMed

    Tan, Ling; Wang, Shunchang; Wang, Yun; He, Mei; Liu, Dahai

    2015-06-01

    Bisphenol A (BPA) is a well-known environmental estrogenic disruptor that causes adverse effects. Recent studies have found that chronic exposure to BPA is associated with a high incidence of several age-related diseases. Aging is characterized by progressive function decline, which affects quality of life. However, the effects of BPA on the aging process are largely unknown. In the present study, by using the nematode Caenorhabditis elegans as a model, we investigated the influence of BPA exposure on the aging process. The decrease in body length, fecundity, and population size and the increased egg laying defection suggested that BPA exposure resulted in fitness loss and reproduction aging in this animal. Lifetime exposure of worms to BPA shortened the lifespan in a dose-dependant manner. Moreover, prolonged BPA exposure resulted in age-related behavior degeneration and the accumulation of lipofuscin and lipid peroxide products. The expression of mitochondria-specific HSP-6 and endoplasmic reticulum (ER)-related HSP-70 exhibited hormetic decrease. The expression of ER-related HSP-4 decreased significantly while HSP-16.2 showed a dose-dependent increase. The decreased expression of GCS-1 and GST-4 implicated the reduced antioxidant ability under BPA exposure, and the increase in SOD-3 expression might be caused by elevated levels of reactive oxygen species (ROS) production. Finally, BPA exposure increased the generation of hydrogen peroxide-related ROS and superoxide anions. Our results suggest that BPA exposure resulted in an accelerated aging process in C. elegans mediated by the induction of oxidative stress.

  15. Graphics processing unit accelerated one-dimensional blood flow computation in the human arterial tree.

    PubMed

    Itu, Lucian; Sharma, Puneet; Kamen, Ali; Suciu, Constantin; Comaniciu, Dorin

    2013-12-01

    One-dimensional blood flow models have been used extensively for computing pressure and flow waveforms in the human arterial circulation. We propose an improved numerical implementation based on a graphics processing unit (GPU) for the acceleration of the execution time of one-dimensional model. A novel parallel hybrid CPU-GPU algorithm with compact copy operations (PHCGCC) and a parallel GPU only (PGO) algorithm are developed, which are compared against previously introduced PHCG versions, a single-threaded CPU only algorithm and a multi-threaded CPU only algorithm. Different second-order numerical schemes (Lax-Wendroff and Taylor series) are evaluated for the numerical solution of one-dimensional model, and the computational setups include physiologically motivated non-periodic (Windkessel) and periodic boundary conditions (BC) (structured tree) and elastic and viscoelastic wall laws. Both the PHCGCC and the PGO implementations improved the execution time significantly. The speed-up values over the single-threaded CPU only implementation range from 5.26 to 8.10 × , whereas the speed-up values over the multi-threaded CPU only implementation range from 1.84 to 4.02 × . The PHCGCC algorithm performs best for an elastic wall law with non-periodic BC and for viscoelastic wall laws, whereas the PGO algorithm performs best for an elastic wall law with periodic BC.

  16. Closing the gap: accelerating the translational process in nanomedicine by proposing standardized characterization techniques.

    PubMed

    Khorasani, Ali A; Weaver, James L; Salvador-Morales, Carolina

    2014-01-01

    On the cusp of widespread permeation of nanomedicine, academia, industry, and government have invested substantial financial resources in developing new ways to better treat diseases. Materials have unique physical and chemical properties at the nanoscale compared with their bulk or small-molecule analogs. These unique properties have been greatly advantageous in providing innovative solutions for medical treatments at the bench level. However, nanomedicine research has not yet fully permeated the clinical setting because of several limitations. Among these limitations are the lack of universal standards for characterizing nanomaterials and the limited knowledge that we possess regarding the interactions between nanomaterials and biological entities such as proteins. In this review, we report on recent developments in the characterization of nanomaterials as well as the newest information about the interactions between nanomaterials and proteins in the human body. We propose a standard set of techniques for universal characterization of nanomaterials. We also address relevant regulatory issues involved in the translational process for the development of drug molecules and drug delivery systems. Adherence and refinement of a universal standard in nanomaterial characterization as well as the acquisition of a deeper understanding of nanomaterials and proteins will likely accelerate the use of nanomedicine in common practice to a great extent.

  17. Closing the gap: accelerating the translational process in nanomedicine by proposing standardized characterization techniques

    PubMed Central

    Khorasani, Ali A; Weaver, James L; Salvador-Morales, Carolina

    2014-01-01

    On the cusp of widespread permeation of nanomedicine, academia, industry, and government have invested substantial financial resources in developing new ways to better treat diseases. Materials have unique physical and chemical properties at the nanoscale compared with their bulk or small-molecule analogs. These unique properties have been greatly advantageous in providing innovative solutions for medical treatments at the bench level. However, nanomedicine research has not yet fully permeated the clinical setting because of several limitations. Among these limitations are the lack of universal standards for characterizing nanomaterials and the limited knowledge that we possess regarding the interactions between nanomaterials and biological entities such as proteins. In this review, we report on recent developments in the characterization of nanomaterials as well as the newest information about the interactions between nanomaterials and proteins in the human body. We propose a standard set of techniques for universal characterization of nanomaterials. We also address relevant regulatory issues involved in the translational process for the development of drug molecules and drug delivery systems. Adherence and refinement of a universal standard in nanomaterial characterization as well as the acquisition of a deeper understanding of nanomaterials and proteins will likely accelerate the use of nanomedicine in common practice to a great extent. PMID:25525356

  18. Accelerating the Gillespie Exact Stochastic Simulation Algorithm using hybrid parallel execution on graphics processing units.

    PubMed

    Komarov, Ivan; D'Souza, Roshan M

    2012-01-01

    The Gillespie Stochastic Simulation Algorithm (GSSA) and its variants are cornerstone techniques to simulate reaction kinetics in situations where the concentration of the reactant is too low to allow deterministic techniques such as differential equations. The inherent limitations of the GSSA include the time required for executing a single run and the need for multiple runs for parameter sweep exercises due to the stochastic nature of the simulation. Even very efficient variants of GSSA are prohibitively expensive to compute and perform parameter sweeps. Here we present a novel variant of the exact GSSA that is amenable to acceleration by using graphics processing units (GPUs). We parallelize the execution of a single realization across threads in a warp (fine-grained parallelism). A warp is a collection of threads that are executed synchronously on a single multi-processor. Warps executing in parallel on different multi-processors (coarse-grained parallelism) simultaneously generate multiple trajectories. Novel data-structures and algorithms reduce memory traffic, which is the bottleneck in computing the GSSA. Our benchmarks show an 8×-120× performance gain over various state-of-the-art serial algorithms when simulating different types of models.

  19. A long-standing hyperglycaemic condition impairs skin barrier by accelerating skin ageing process.

    PubMed

    Park, Hwa-Young; Kim, Jae-Hong; Jung, Minyoung; Chung, Choon Hee; Hasham, Rosnani; Park, Chang Seo; Choi, Eung Ho

    2011-12-01

    Uncontrolled chronic hyperglycaemia including type 2 diabetes mellitus (DM) induces many skin problems related to chronic impaired skin barrier state. However, little is known about the skin barrier state of chronic hyperglycaemia patients, the dysfunction of which may be a major cause of their skin problems. In this study, we investigated whether a long-standing hyperglycaemic condition including type 2 DM impairs skin barrier homoeostasis in proportion to the duration and its pathomechanism. We utilized the Otsuka Long-Evans Tokushima Fatty (OLETF) rats as an animal model of long-standing hyperglycaemia and Long-Evans Tokushima Otsuka rats as a control strain. We confirmed that a long-standing hyperglycaemia delayed skin barrier homoeostasis, which correlated with haemoglobin A1c levels. OLETF rats as a long-standing hyperglycaemia model exhibited decreased epidermal lipid synthesis and antimicrobial peptide expression with increasing age. Decreased epidermal lipid synthesis accounted for decreased lamellar body production. In addition, OLETF rats had significantly higher serum levels of advanced glycation end products (AGEs) and elevated levels of the receptor for AGE in the epidermis. A long-standing hyperglycaemic condition impairs skin barrier function including permeability and antimicrobial barriers by accelerating skin ageing process in proportion to the duration of hyperglycaemia, which could be a major pathophysiology underlying cutaneous complications of DM.

  20. Accelerator mass spectrometry detection of beryllium ions in the antigen processing and presentation pathway

    SciTech Connect

    Tooker, Brian C.; Brindley, Stephen M.; Chiarappa-Zucca, Marina L.; Turteltaub, Kenneth W.; Newman, Lee S.

    2014-06-16

    We report that exposure to small amounts of beryllium (Be) can result in beryllium sensitization and progression to Chronic Beryllium Disease (CBD). In CBD, beryllium is presented to Be-responsive T-cells by professional antigen-presenting cells (APC). This presentation drives T-cell proliferation and pro-inflammatory cytokine (IL-2, TNFα, and IFNγ) production and leads to granuloma formation. The mechanism by which beryllium enters an APC and is processed to become part of the beryllium antigen complex has not yet been elucidated. Developing techniques for beryllium detection with enough sensitivity has presented a barrier to further investigation. The objective of this study was to demonstrate that Accelerator Mass Spectrometry (AMS) is sensitive enough to quantify the amount of beryllium presented by APC to stimulate Be-responsive T-cells. To achieve this goal, APC - which may or may not stimulate Be-responsive T-cells - were cultured with Be-ferritin. Then, by utilizing AMS, the amount of beryllium processed for presentation was determined. Further, IFNγ intracellular cytokine assays were performed to demonstrate that Be-ferritin (at levels used in the experiments) could stimulate Be-responsive T-cells when presented by an APC of the correct HLA type (HLA-DP0201). The results indicated that Be-responsive T-cells expressed IFNγ only when APC with the correct HLA type were able to process Be for presentation. Utilizing AMS, we determined that APC with HLA-DP0201 had membrane fractions containing 0.17-0.59 ng Be and APC with HLA-DP0401 had membrane fractions bearing 0.40-0.45 ng Be. However, HLA-DP0401 APC had 20-times more Be associated with the whole cells (57.68-61.12 ng) then HLA-DP0201 APC (0.90-3.49 ng). As these findings demonstrate, AMS detection of picogram levels of Be processed by APC is possible. Further, regardless of form, Be requires processing by APC to successfully stimulate Be-responsive T-cells to generate IFNγ.

  1. Accelerator mass spectrometry detection of beryllium ions in the antigen processing and presentation pathway

    DOE PAGES

    Tooker, Brian C.; Brindley, Stephen M.; Chiarappa-Zucca, Marina L.; ...

    2014-06-16

    We report that exposure to small amounts of beryllium (Be) can result in beryllium sensitization and progression to Chronic Beryllium Disease (CBD). In CBD, beryllium is presented to Be-responsive T-cells by professional antigen-presenting cells (APC). This presentation drives T-cell proliferation and pro-inflammatory cytokine (IL-2, TNFα, and IFNγ) production and leads to granuloma formation. The mechanism by which beryllium enters an APC and is processed to become part of the beryllium antigen complex has not yet been elucidated. Developing techniques for beryllium detection with enough sensitivity has presented a barrier to further investigation. The objective of this study was to demonstratemore » that Accelerator Mass Spectrometry (AMS) is sensitive enough to quantify the amount of beryllium presented by APC to stimulate Be-responsive T-cells. To achieve this goal, APC - which may or may not stimulate Be-responsive T-cells - were cultured with Be-ferritin. Then, by utilizing AMS, the amount of beryllium processed for presentation was determined. Further, IFNγ intracellular cytokine assays were performed to demonstrate that Be-ferritin (at levels used in the experiments) could stimulate Be-responsive T-cells when presented by an APC of the correct HLA type (HLA-DP0201). The results indicated that Be-responsive T-cells expressed IFNγ only when APC with the correct HLA type were able to process Be for presentation. Utilizing AMS, we determined that APC with HLA-DP0201 had membrane fractions containing 0.17-0.59 ng Be and APC with HLA-DP0401 had membrane fractions bearing 0.40-0.45 ng Be. However, HLA-DP0401 APC had 20-times more Be associated with the whole cells (57.68-61.12 ng) then HLA-DP0201 APC (0.90-3.49 ng). As these findings demonstrate, AMS detection of picogram levels of Be processed by APC is possible. Further, regardless of form, Be requires processing by APC to successfully stimulate Be-responsive T-cells to generate IFNγ.« less

  2. Accelerator mass spectrometry detection of beryllium ions in the antigen processing and presentation pathway.

    PubMed

    Tooker, Brian C; Brindley, Stephen M; Chiarappa-Zucca, Marina L; Turteltaub, Kenneth W; Newman, Lee S

    2015-01-01

    Exposure to small amounts of beryllium (Be) can result in beryllium sensitization and progression to Chronic Beryllium Disease (CBD). In CBD, beryllium is presented to Be-responsive T-cells by professional antigen-presenting cells (APC). This presentation drives T-cell proliferation and pro-inflammatory cytokine (IL-2, TNFα, and IFNγ) production and leads to granuloma formation. The mechanism by which beryllium enters an APC and is processed to become part of the beryllium antigen complex has not yet been elucidated. Developing techniques for beryllium detection with enough sensitivity has presented a barrier to further investigation. The objective of this study was to demonstrate that Accelerator Mass Spectrometry (AMS) is sensitive enough to quantify the amount of beryllium presented by APC to stimulate Be-responsive T-cells. To achieve this goal, APC - which may or may not stimulate Be-responsive T-cells - were cultured with Be-ferritin. Then, by utilizing AMS, the amount of beryllium processed for presentation was determined. Further, IFNγ intracellular cytokine assays were performed to demonstrate that Be-ferritin (at levels used in the experiments) could stimulate Be-responsive T-cells when presented by an APC of the correct HLA type (HLA-DP0201). The results indicated that Be-responsive T-cells expressed IFNγ only when APC with the correct HLA type were able to process Be for presentation. Utilizing AMS, it was determined that APC with HLA-DP0201 had membrane fractions containing 0.17-0.59 ng Be and APC with HLA-DP0401 had membrane fractions bearing 0.40-0.45 ng Be. However, HLA-DP0401 APC had 20-times more Be associated with the whole cells (57.68-61.12 ng) than HLA-DP0201 APC (0.90-3.49 ng). As these findings demonstrate, AMS detection of picogram levels of Be processed by APC is possible. Further, regardless of form, Be requires processing by APC to successfully stimulate Be-responsive T-cells to generate IFNγ.

  3. The vulnerable and unstable atherosclerotic plaque.

    PubMed

    Fishbein, Michael C

    2010-01-01

    The lesion responsible for the overwhelming majority of acute coronary events is plaque disruption or erosion with superimposed thrombosis. The term "vulnerable plaque" has been used to describe those atherosclerotic plaques that are particularly susceptible to disruption. Vulnerable plaques are generally characterized as those having a thin inflamed fibrous cap over a very large lipid core. However, only a small percentage of such plaques rupture, and plaques with different characteristics may also rupture and thrombose. Most autopsy, intravascular ultrasound, and recent computed tomography angiographic studies of coronary arteries reveal large plaques at sites of rupture. While angiographic data are said to show less severe narrowing at sites of plaque rupture, actual review of data indicates that, even angiographically, more than 50% of plaques have greater than 75% cross-sectional area stenosis at sites of plaque rupture. If plaque rupture is more common at the shoulder region of a plaque, one could envision that this would be at a peripheral site of the plaque where the plaque may not be as large or occlusive. New knowledge about vulnerable plaques is emerging through the evolution of novel techniques used to study plaques in vivo. These methods combine sophisticated imaging techniques, often in conjunction with molecular biomarkers, that provide new insights into plaque biology. Since atherosclerotic coronary artery disease is such a widespread and fatal disease, it is important that we continue to strive for a greater understanding of the nature of the vulnerable plaque. Only then can rational interventions for this disorder be developed and implemented.

  4. Boric Acid Reduces the Formation of DNA Double Strand Breaks and Accelerates Wound Healing Process.

    PubMed

    Tepedelen, Burcu Erbaykent; Soya, Elif; Korkmaz, Mehmet

    2016-12-01

    Boron is absorbed by the digestive and respiratory system, and it was considered that it is converted to boric acid (BA), which was distributed to all tissues above 90 %. The biochemical essentiality of boron element is caused by boric acid because it affects the activity of several enzymes involved in the metabolism. DNA damage repair mechanisms and oxidative stress regulation is quite important in the transition stage from normal to cancerous cells; thus, this study was conducted to investigate the protective effect of boric acid on DNA damage and wound healing in human epithelial cell line. For this purpose, the amount of DNA damage occurred with irinotecan (CPT-11), etoposide (ETP), doxorubicin (Doxo), and H2O2 was determined by immunofluorescence through phosphorylation of H2AX((Ser139)) and pATM((Ser1981)) in the absence and presence of BA. Moreover, the effect of BA on wound healing has been investigated in epithelial cells treated with these agents. Our results demonstrated that H2AX((Ser139)) foci numbers were significantly decreased in the presence of BA while wound healing was accelerated by BA compared to that in the control and only drug-treated cells. Eventually, the results indicate that BA reduced the formation of DNA double strand breaks caused by agents as well as improving the wound healing process. Therefore, we suggest that boric acid has important therapeutical effectiveness and may be used in the treatment of inflammatory diseases where oxidative stress and wound healing process plays an important role.

  5. Graphics Processing Unit Acceleration and Parallelization of GENESIS for Large-Scale Molecular Dynamics Simulations.

    PubMed

    Jung, Jaewoon; Naurse, Akira; Kobayashi, Chigusa; Sugita, Yuji

    2016-10-11

    The graphics processing unit (GPU) has become a popular computational platform for molecular dynamics (MD) simulations of biomolecules. A significant speedup in the simulations of small- or medium-size systems using only a few computer nodes with a single or multiple GPUs has been reported. Because of GPU memory limitation and slow communication between GPUs on different computer nodes, it is not straightforward to accelerate MD simulations of large biological systems that contain a few million or more atoms on massively parallel supercomputers with GPUs. In this study, we develop a new scheme in our MD software, GENESIS, to reduce the total computational time on such computers. Computationally intensive real-space nonbonded interactions are computed mainly on GPUs in the scheme, while less intensive bonded interactions and communication-intensive reciprocal-space interactions are performed on CPUs. On the basis of the midpoint cell method as a domain decomposition scheme, we invent the single particle interaction list for reducing the GPU memory usage. Since total computational time is limited by the reciprocal-space computation, we utilize the RESPA multiple time-step integration and reduce the CPU resting time by assigning a subset of nonbonded interactions on CPUs as well as on GPUs when the reciprocal-space computation is skipped. We validated our GPU implementations in GENESIS on BPTI and a membrane protein, porin, by MD simulations and an alanine-tripeptide by REMD simulations. Benchmark calculations on TSUBAME supercomputer showed that an MD simulation of a million atoms system was scalable up to 256 computer nodes with GPUs.

  6. Translational Mini-Review Series on Immunology of Vascular Disease: Accelerated atherosclerosis in vasculitis

    PubMed Central

    Tervaert, J W Cohen

    2009-01-01

    Premature atherosclerosis has been observed during the course of different systemic inflammatory diseases such as rheumatoid arthritis and sytemic lupus erythematosus. Remarkably, relatively few studies have been published on the occurrence of accelerated atherosclerosis in patients with vasculitis. In giant cell arteritis (GCA), mortality because of ischaemic heart disease is not increased. In addition, intima media thickness (IMT) is lower in patients with GCA than in age-matched controls. In contrast, IMT is increased significantly in Takayasu arteritis, another form of large vessel vasculitis occurring in younger patients. In Takayasu arteritis and in Kawasaki disease, a form of medium-sized vessel vasculitis, accelerated atherosclerosis has been well documented. In small vessel vasculitis because of anti-neutrophil cytoplasmic autoantibodies-associated vasculitis, cardiovascular diseases are a major cause of mortality. IMT measurements reveal conflicting results. During active disease these patients experience acceleration of the atherosclerotic process. However, when inflammation is controlled, these patients have atherosclerotic development as in healthy subjects. Several risk factors, such as diabetes and hypertension, are present more often in patients with vasculitis compared with healthy controls. In addition, steroids may be pro-atherogenic. Most importantly, many patients have impaired renal function, persistent proteinuria and increased levels of C-reactive protein, well-known risk factors for acceleration of atherosclerosis. Enhanced oxidation processes, persistently activated T cells and reduced numbers of regulatory T cells are among the many pathophysiological factors that play a role during acceleration of atherogenesis. Finally, autoantibodies that may be relevant for acceleration of atherosclerosis are found frequently in elevated titres in patients with vasculitis. Because patients have an increased risk for cardiovascular events, vasculitis

  7. Atherosclerotic plaque regression: fact or fiction?

    PubMed

    Shanmugam, Nesan; Román-Rego, Ana; Ong, Peter; Kaski, Juan Carlos

    2010-08-01

    Coronary artery disease is the major cause of death in the western world. The formation and rapid progression of atheromatous plaques can lead to serious cardiovascular events in patients with atherosclerosis. The better understanding, in recent years, of the mechanisms leading to atheromatous plaque growth and disruption and the availability of powerful HMG CoA-reductase inhibitors (statins) has permitted the consideration of plaque regression as a realistic therapeutic goal. This article reviews the existing evidence underpinning current therapeutic strategies aimed at achieving atherosclerotic plaque regression. In this review we also discuss imaging modalities for the assessment of plaque regression, predictors of regression and whether plaque regression is associated with a survival benefit.

  8. Pulsatile Flow Studies in Atherosclerotic Carotid Bifurcation

    NASA Astrophysics Data System (ADS)

    Bale-Glickman, Jocelyn; Selby, Kathy; Saloner, David; Savas, Omer

    2002-11-01

    Particle image velocimetry and flow visualization techniques are used to study flow in models of atherosclerotic carotid bifurcations. The models exactly replicate the interior geometry of plaque excised from patients. The input flow is a physiological waveform derived from Doppler Ultrasound scans done on the patients before surgery. The systolic and diastolic Reynolds numbers are 200 and 900 respectively. The complex internal geometry of the diseased artery combined with the pulsatile input flows give exceedingly complex flow patterns. These flow patterns include internal jets, three-dimensional shear layers, stagnation lines, and multiple recirculation and separation regions. Ensemble averaged and instantaneous flow fields are compared. Wall shear stresses at the stenoses are estimated to be on the order of 10 PA. The physiological input flows are also compared to flows when the waveform is sinusoidal.

  9. Potential Anti-Atherosclerotic Properties of Astaxanthin

    PubMed Central

    Kishimoto, Yoshimi; Yoshida, Hiroshi; Kondo, Kazuo

    2016-01-01

    Astaxanthin is a naturally occurring red carotenoid pigment classified as a xanthophyll, found in microalgae and seafood such as salmon, trout, and shrimp. This review focuses on astaxanthin as a bioactive compound and outlines the evidence associated with its potential role in the prevention of atherosclerosis. Astaxanthin has a unique molecular structure that is responsible for its powerful antioxidant activities by quenching singlet oxygen and scavenging free radicals. Astaxanthin has been reported to inhibit low-density lipoprotein (LDL) oxidation and to increase high-density lipoprotein (HDL)-cholesterol and adiponectin levels in clinical studies. Accumulating evidence suggests that astaxanthin could exert preventive actions against atherosclerotic cardiovascular disease (CVD) via its potential to improve oxidative stress, inflammation, lipid metabolism, and glucose metabolism. In addition to identifying mechanisms of astaxanthin bioactivity by basic research, much more epidemiological and clinical evidence linking reduced CVD risk with dietary astaxanthin intake is needed. PMID:26861359

  10. Nuclear Molecular Imaging for Vulnerable Atherosclerotic Plaques

    PubMed Central

    Lee, Soo Jin

    2015-01-01

    Atherosclerosis is an inflammatory disease as well as a lipid disorder. Atherosclerotic plaque formed in vessel walls may cause ischemia, and the rupture of vulnerable plaque may result in fatal events, like myocardial infarction or stroke. Because morphological imaging has limitations in diagnosing vulnerable plaque, molecular imaging has been developed, in particular, the use of nuclear imaging probes. Molecular imaging targets various aspects of vulnerable plaque, such as inflammatory cell accumulation, endothelial activation, proteolysis, neoangiogenesis, hypoxia, apoptosis, and calcification. Many preclinical and clinical studies have been conducted with various imaging probes and some of them have exhibited promising results. Despite some limitations in imaging technology, molecular imaging is expected to be used both in the research and clinical fields as imaging instruments become more advanced. PMID:26357491

  11. Ophthalmic masquerades of the atherosclerotic carotids

    PubMed Central

    Arthur, Anupriya; Alexander, Anika; Bal, Simerpreet; Sivadasan, Ajith; Aaron, Sanjith

    2014-01-01

    Patients with carotid atherosclerosis can present with ophthalmic symptoms. These symptoms and signs can be due to retinal emboli, hypoperfusion of the retina and choroid, opening up of collateral channels, or chronic hypoperfusion of the globe (ocular ischemic syndrome). These pathological mechanisms can produce many interesting signs and a careful history can bring out important past symptoms pointing toward the carotid as the source of the patient's presenting symptom. Such patients are at high risk for an ischemic stroke, especially in the subsequent few days following their first acute symptom. It is important for clinicians to be familiar with these ophthalmic symptoms and signs caused by carotid atherosclerosis for making an early diagnosis and to take appropriate measures to prevent a stroke. This review elaborates the clinical features, importance, and implications of various ophthalmic symptoms and signs resulting from atherosclerotic carotid artery disease. PMID:24817748

  12. Schooling in Times of Acceleration

    ERIC Educational Resources Information Center

    Buddeberg, Magdalena; Hornberg, Sabine

    2017-01-01

    Modern societies are characterised by forms of acceleration, which influence social processes. Sociologist Hartmut Rosa has systematised temporal structures by focusing on three categories of social acceleration: technical acceleration, acceleration of social change, and acceleration of the pace of life. All three processes of acceleration are…

  13. Monte Carlo Modeling of Electronuclear Processes in Experimental Accelerator Driven Systems

    NASA Astrophysics Data System (ADS)

    Polanski, Aleksander

    2000-01-01

    The paper presents results of Monte Carlo modeling of an experimental Accelerator Driven System (ADS), which employs a subcritical assembly and a 660 MeV proton accelerator operating at the Laboratory of Nuclear Problems of the Joint Institute for Nuclear Research in Dubna. The mix of oxides (PuO2 + UO2) MOX fuel designed for the reactor will be adopted for the core of the assembly. The present conceptual design of the experimental subcritical assembly in Dubna is based on the core with a nominal unit capacity of 30 kW (thermal). This corresponds to the multiplication coefficient keff= 0.945 and the accelerator beam power of 1 kW.

  14. Subsurface ablation of atherosclerotic plaque using ultrafast laser pulses

    PubMed Central

    Lanvin, Thomas; Conkey, Donald B.; Frobert, Aurelien; Valentin, Jeremy; Goy, Jean-Jacques; Cook, Stéphane; Giraud, Marie-Noelle; Psaltis, Demetri

    2015-01-01

    We perform subsurface ablation of atherosclerotic plaque using ultrafast pulses. Excised mouse aortas containing atherosclerotic plaque were ablated with ultrafast near-infrared (NIR) laser pulses. Optical coherence tomography (OCT) was used to observe the ablation result, while the physical damage was inspected in histological sections. We characterize the effects of incident pulse energy on surface damage, ablation hole size, and filament propagation. We find that it is possible to ablate plaque just below the surface without causing surface damage, which motivates further investigation of ultrafast ablation for subsurface atherosclerotic plaque removal. PMID:26203381

  15. Subsurface ablation of atherosclerotic plaque using ultrafast laser pulses.

    PubMed

    Lanvin, Thomas; Conkey, Donald B; Frobert, Aurelien; Valentin, Jeremy; Goy, Jean-Jacques; Cook, Stéphane; Giraud, Marie-Noelle; Psaltis, Demetri

    2015-07-01

    We perform subsurface ablation of atherosclerotic plaque using ultrafast pulses. Excised mouse aortas containing atherosclerotic plaque were ablated with ultrafast near-infrared (NIR) laser pulses. Optical coherence tomography (OCT) was used to observe the ablation result, while the physical damage was inspected in histological sections. We characterize the effects of incident pulse energy on surface damage, ablation hole size, and filament propagation. We find that it is possible to ablate plaque just below the surface without causing surface damage, which motivates further investigation of ultrafast ablation for subsurface atherosclerotic plaque removal.

  16. Atorvastatin Upregulates the Expression of miR-126 in Apolipoprotein E-knockout Mice with Carotid Atherosclerotic Plaque.

    PubMed

    Pan, Xudong; Hou, Rongyao; Ma, Aijun; Wang, Ting; Wu, Mei; Zhu, Xiaoyan; Yang, Shaonan; Xiao, Xing

    2017-01-01

    Carotid atherosclerosis (AS) is a chronic inflammatory disease of the carotid arterial wall, which is very important in terms of the occurrence of cerebral vascular accidents. Studies have demonstrated that microRNAs (miRNAs) and their target genes are involved in the formation of atherosclerosis and that atorvastatin might reduce atherosclerotic plaques by regulating the expression of miRNAs. However, the related mechanism is not yet known. In this study, we first investigated the effects of atorvastatin on miR-126 and its target gene, i.e., vascular cell adhesion molecule-1 (VCAM-1) in apolipoprotein E-knockout (ApoE-/-) mice with carotid atherosclerotic plaque in vivo. We compared the expressions of miR-126 and VCAM-1 between the control, atherosclerotic model and atorvastatin treatment groups of ApoE-/- mice using RT-PCR and Western blot. We found the miR-126 expression was significantly down-regulated, and the VCAM-1 expression was significantly up-regulated in the atherosclerotic model group, which accelerated the progression of atherosclerosis in the ApoE-/- mice. These results following atorvastatin treatment indicated that miR-126 expression was significantly up-regulated, VCAM-1 expression was significantly down-regulated and atherosclerotic lesions were reduced. The present results might explain the mechanism by which miR-126 is involved in the formation of atherosclerosis in vivo. Our study first indicated that atorvastatin might exert its anti-inflammatory effects in atherosclerosis by regulating the expressions of miR-126 and VCAM-1 in vivo.

  17. How to manage hypertension with atherosclerotic renal artery stenosis?

    PubMed

    Ricco, Jean-Baptiste; Belmonte, Romain; Illuminati, Guilio; Barral, Xavier; Schneider, Fabrice; Chavent, Bertrand

    2017-04-01

    The management of atherosclerotic renal artery stenosis (ARAS) in patients with hypertension has been the topic of great controversy. Major contemporary clinical trials such as the Cardiovascular Outcomes for Renal Artery lesions (CORAL) and Angioplasty and Stenting for Renal Atherosclerotic lesions (ASTRAL) have failed to show significant benefit of revascularization over medical management in controlling blood pressure and preserving renal function. We present here the implications and limitations of these trials and formulate recommendations for management of ARAS.

  18. Molecular dynamics-based virtual screening: accelerating the drug discovery process by high-performance computing.

    PubMed

    Ge, Hu; Wang, Yu; Li, Chanjuan; Chen, Nanhao; Xie, Yufang; Xu, Mengyan; He, Yingyan; Gu, Xinchun; Wu, Ruibo; Gu, Qiong; Zeng, Liang; Xu, Jun

    2013-10-28

    High-performance computing (HPC) has become a state strategic technology in a number of countries. One hypothesis is that HPC can accelerate biopharmaceutical innovation. Our experimental data demonstrate that HPC can significantly accelerate biopharmaceutical innovation by employing molecular dynamics-based virtual screening (MDVS). Without using HPC, MDVS for a 10K compound library with tens of nanoseconds of MD simulations requires years of computer time. In contrast, a state of the art HPC can be 600 times faster than an eight-core PC server is in screening a typical drug target (which contains about 40K atoms). Also, careful design of the GPU/CPU architecture can reduce the HPC costs. However, the communication cost of parallel computing is a bottleneck that acts as the main limit of further virtual screening improvements for drug innovations.

  19. Ab initio nonadiabatic dynamics of multichromophore complexes: a scalable graphical-processing-unit-accelerated exciton framework.

    PubMed

    Sisto, Aaron; Glowacki, David R; Martinez, Todd J

    2014-09-16

    ("fragmenting") a molecular system and then stitching it back together. In this Account, we address both of these problems, the first by using graphical processing units (GPUs) and electronic structure algorithms tuned for these architectures and the second by using an exciton model as a framework in which to stitch together the solutions of the smaller problems. The multitiered parallel framework outlined here is aimed at nonadiabatic dynamics simulations on large supramolecular multichromophoric complexes in full atomistic detail. In this framework, the lowest tier of parallelism involves GPU-accelerated electronic structure theory calculations, for which we summarize recent progress in parallelizing the computation and use of electron repulsion integrals (ERIs), which are the major computational bottleneck in both density functional theory (DFT) and time-dependent density functional theory (TDDFT). The topmost tier of parallelism relies on a distributed memory framework, in which we build an exciton model that couples chromophoric units. Combining these multiple levels of parallelism allows access to ground and excited state dynamics for large multichromophoric assemblies. The parallel excitonic framework is in good agreement with much more computationally demanding TDDFT calculations of the full assembly.

  20. Optimization of the accelerated curing process of concrete using a fibre Bragg grating-based control system and microwave technology

    NASA Astrophysics Data System (ADS)

    Fabian, Matthias; Jia, Yaodong; Shi, Shi; McCague, Colum; Bai, Yun; Sun, Tong; Grattan, Kenneth T. V.

    2016-05-01

    In this paper, an investigation into the suitability of using fibre Bragg gratings (FBGs) for monitoring the accelerated curing process of concrete in a microwave heating environment is presented. In this approach, the temperature data provided by the FBGs are used to regulate automatically the microwave power so that a pre-defined temperature profile is maintained to optimize the curing process, achieving early strength values comparable to those of conventional heat-curing techniques but with significantly reduced energy consumption. The immunity of the FBGs to interference from the microwave radiation used ensures stable readings in the targeted environment, unlike conventional electronic sensor probes.

  1. Accelerating quantum chemistry calculations with graphical processing units - toward in high-density (HD) silico drug discovery.

    PubMed

    Hagiwara, Yohsuke; Ohno, Kazuki; Orita, Masaya; Koga, Ryota; Endo, Toshio; Akiyama, Yutaka; Sekijima, Masakazu

    2013-09-01

    The growing power of central processing units (CPU) has made it possible to use quantum mechanical (QM) calculations for in silico drug discovery. However, limited CPU power makes large-scale in silico screening such as virtual screening with QM calculations a challenge. Recently, general-purpose computing on graphics processing units (GPGPU) has offered an alternative, because of its significantly accelerated computational time over CPU. Here, we review a GPGPU-based supercomputer, TSUBAME2.0, and its promise for next generation in silico drug discovery, in high-density (HD) silico drug discovery.

  2. What can we learn from inverse methods regarding the processes behind the acceleration and retreat of Helheim glacier (Greenland)?

    NASA Astrophysics Data System (ADS)

    Gagliardini, O.; Gillet-chaulet, F.; Martin, N.; Monnier, J.; Singh, J.

    2011-12-01

    Greenland outlet glaciers control the ice discharge toward the sea and the resulting contribution to sea level rise. Physical processes at the root of the observed acceleration and retreat, - decrease of the back force at the calving terminus, increase of basal lubrication and decrease of the lateral friction -, are still not well understood. All these three processes certainly play a role but their relative contributions have not yet been quantified. Helheim glacier, located on the east coast of Greenland, has undergone an enhanced retreat since 2003, and this retreat was concurrent with accelerated ice flow. In this study, the flowline dataset including surface elevation, surface velocity and front position of Helheim from 2001 to 2006 is used to quantify the sensitivity of each of these processes. For that, we used the full-Stokes finite element ice flow model DassFlow/Ice, including adjoint code and full 4d-var data assimilation process in which the control variables are the basal and lateral friction parameters as well as the calving front pressure. For each available date, the sensitivity of each processes is first studied and an optimal distribution is then inferred from the surface measurements. Using this optimal distribution of these parameters, a transient simulation is performed over the whole dataset period. The relative contributions of the basal friction, lateral friction and front back force are then discussed under the light of these new results.

  3. Accelerating the commercialization of university technologies for military healthcare applications: the role of the proof of concept process

    NASA Astrophysics Data System (ADS)

    Ochoa, Rosibel; DeLong, Hal; Kenyon, Jessica; Wilson, Eli

    2011-06-01

    The von Liebig Center for Entrepreneurism and Technology Advancement at UC San Diego (vonliebig.ucsd.edu) is focused on accelerating technology transfer and commercialization through programs and education on entrepreneurism. Technology Acceleration Projects (TAPs) that offer pre-venture grants and extensive mentoring on technology commercialization are a key component of its model which has been developed over the past ten years with the support of a grant from the von Liebig Foundation. In 2010, the von Liebig Entrepreneurism Center partnered with the U.S. Army Telemedicine and Advanced Technology Research Center (TATRC), to develop a regional model of Technology Acceleration Program initially focused on military research to be deployed across the nation to increase awareness of military medical needs and to accelerate the commercialization of novel technologies to treat the patient. Participants to these challenges are multi-disciplinary teams of graduate students and faculty in engineering, medicine and business representing universities and research institutes in a region, selected via a competitive process, who receive commercialization assistance and funding grants to support translation of their research discoveries into products or services. To validate this model, a pilot program focused on commercialization of wireless healthcare technologies targeting campuses in Southern California has been conducted with the additional support of Qualcomm, Inc. Three projects representing three different universities in Southern California were selected out of forty five applications from ten different universities and research institutes. Over the next twelve months, these teams will conduct proof of concept studies, technology development and preliminary market research to determine the commercial feasibility of their technologies. This first regional program will help build the needed tools and processes to adapt and replicate this model across other regions in the

  4. Endovascular Treatment of Symptomatic Intracranial Atherosclerotic Disease

    PubMed Central

    Short, Jody L.; Majid, Arshad; Hussain, Syed I.

    2011-01-01

    Symptomatic intracranial atherosclerotic disease (ICAD) is responsible for approximately 10% of all ischemic strokes in the United States. The risk of recurrent stroke may be as high as 35% in patient with critical stenosis >70% in diameter narrowing. Recent advances in medical and endovascular therapy have placed ICAD at the forefront of clinical stroke research to optimize the best medical and endovascular approach to treat this important underlying stroke etiology. Analysis of symptomatic ICAD studies lead to the question that whether angioplasty and/or stenting is a safe, suitable, and efficacious therapeutic strategy in patients with critical stenoses that are deemed refractory to medical management. Most of the currently available data in support of angioplasty and/or stenting in high risk patients with severe symptomatic ICAD is in the form of case series and randomized trial results of endovascular therapy versus medical treatment are awaited. This is a comprehensive review of the state of the art in the endovascular approach with angioplasty and/or stenting of symptomatic ICAD. PMID:21359195

  5. Primary Stenting of Intracranial Atherosclerotic Stenoses

    SciTech Connect

    Straube, T. Stingele, Robert; Jansen, Olav

    2005-04-15

    Purpose: To determine the feasibility and safety of stenting intracranial atherosclerotic stenoses.Methods: In 12 patients the results of primary intracranial stenting were evaluated retrospectively. Patient ages ranged from 49 to 79 years (mean 64 years). Six patients presented with stenoses in the anterior circulation, and six had stenosis in the posterior circulation. One patient presented with extra- and intracranial tandem stenosis of the left internal carotid artery. Three patients presented with acute basilar thrombosis, caused by high-grade basilar stenoses.Results: Intracranial stenoses were successfully stented in 11 of 12 patients. In one patient the stent could not be advanced over the carotid siphon to reach the stenosis of the ophthalmic internal carotid artery. Follow-up digital subtraction angiographic studies were obtained in two patients who had presented with new neurologic signs or symptoms. In both cases the angiogram did not show any relevant stenotic endothelial hyperplasia. In one patient, after local thrombolysis the stenosis turned out to be so narrow that balloon angioplasty had to be performed before stent deployment. All three patients treated for stenosis-related basilar thrombosis died due to brainstem infarction that had ensued before the intervention.Conclusions: Prophylactic primary stenting of intracranial stenoses of the anterior or posterior cerebral circulation can be performed with a low complication rate; technical problems such as stent flexibility must still be solved. Local thrombolysis followed by stenting in stenosis-related thrombotic occlusion is technically possible.

  6. Heat Shock Proteins: Mediators of Atherosclerotic Development.

    PubMed

    Deniset, Justin F; Pierce, Grant N

    2015-01-01

    Heat shock proteins play important housekeeping roles in a variety of cells within the body during normal control conditions. The many different functions for heat shock proteins in the cell depend upon the specific heat shock protein involved. Each protein is nominally differentiated based upon its molecular size. However, in addition to their role in normal cell function, heat shock proteins may play an even more important role as pro-survival proteins conserved through evolution to protect the cell from a variety of stresses. The ability of a cell to withstand these environmental stresses is critical to its capacity to adapt and remain viable. Loss of this ability may lead to pathological states. Abnormal localization, structure or function of the heat shock proteins has been associated with many pathologies, including those involving heart disease. Heat shock proteins like HSP60 and HSP70 in particular have been identified as playing important roles in inflammation and immune reactions. Inflammation has been identified recently as an important pathological risk factor for heart disease. It is perhaps not surprising therefore, that heat shock protein family has been increasingly identified as an important intracellular pathway associated with inflammatory-mediated heart conditions including atherosclerosis. This paper reviews the evidence in support of a role for heat shock proteins in cardiovascular disease and the potential to target these proteins to alter the progression of atherosclerotic disease.

  7. Modeling of Mechanical Stress Exerted by Cholesterol Crystallization on Atherosclerotic Plaques

    PubMed Central

    Cui, Dongyao; Yu, Xiaojun; Chen, Si; Liu, Xinyu; Tang, Hongying; Wang, Xianghong; Liu, Linbo

    2016-01-01

    Plaque rupture is the critical cause of cardiovascular thrombosis, but the detailed mechanisms are not fully understood. Recent studies have found abundant cholesterol crystals in ruptured plaques, and it has been proposed that the rapid expansion of cholesterol crystals in a limited space during crystallization may contribute to plaque rupture. To evaluate the effect of cholesterol crystal growth on atherosclerotic plaques, we modeled the expansion of cholesterol crystals during the crystallization process in the necrotic core and estimated the stress on the thin cap with different arrangements of cholesterol crystals. We developed a two-dimensional finite element method model of atherosclerotic plaques containing expanding cholesterol crystals and investigated the effect of the magnitude and distribution of crystallization on the peak circumferential stress born by the cap. Using micro-optical coherence tomography (μOCT), we extracted the cross-sectional geometric information of cholesterol crystals in human atherosclerotic aorta tissue ex vivo and applied the information to the model. The results demonstrate that (1) the peak circumference stress is proportionally dependent on the cholesterol crystal growth; (2) cholesterol crystals at the cap shoulder impose the highest peak circumference stress; and (3) spatial distributions of cholesterol crystals have a significant impact on the peak circumference stress: evenly distributed cholesterol crystals exert less peak circumferential stress on the cap than concentrated crystals. PMID:27149381

  8. Positron emission tomography of the vulnerable atherosclerotic plaque in man – a contemporary review

    PubMed Central

    Pedersen, Sune F; Hag, Anne Mette F; Klausen, Thomas L; Ripa, Rasmus S; Bodholdt, Rasmus P; Kjær, Andreas

    2014-01-01

    Atherosclerosis is the primary underlying cause of cardiovascular disease (CVD). It is the leading cause of morbidity and mortality in the Western world today and is set to become the prevailing disease and major cause of death worldwide by 2020. In the 1950s surgical intervention was introduced to treat symptomatic patients with high-grade carotid artery stenosis due to atherosclerosis – a procedure known as carotid endarterectomy (CEA). By removing the atherosclerotic plaque from the affected carotid artery of these patients, CEA is beneficial by preventing subsequent ipsilateral ischemic stroke. However, it is known that patients with low to intermediate artery stenosis may still experience ischemic events, leading clinicians to consider plaque composition as an important feature of atherosclerosis. Today molecular imaging can be used for characterization, visualization and quantification of cellular and subcellular physiological processes as they take place in vivo; using this technology we can obtain valuable information on atherosclerostic plaque composition. Applying molecular imaging clinically to atherosclerotic disease therefore has the potential to identify atherosclerotic plaques vulnerable to rupture. This could prove to be an important tool for the selection of patients for CEA surgery in a health system increasingly focused on individualized treatment. This review focuses on current advances and future developments of in vivo atherosclerosis PET imaging in man. PMID:24289282

  9. Neutron activation processes simulation in an Elekta medical linear accelerator head.

    PubMed

    Juste, B; Miró, R; Verdú, G; Díez, S; Campayo, J M

    2014-01-01

    Monte Carlo estimation of the giant-dipole-resonance (GRN) photoneutrons inside the Elekta Precise LINAC head (emitting a 15 MV photon beam) were performed using the MCNP6 (general-purpose Monte Carlo N-Particle code, version 6). Each component of LINAC head geometry and materials were modelled in detail using the given manufacturer information. Primary photons generate photoneutrons and its transport across the treatment head was simulated, including the (n, γ) reactions which undergo activation products. The MCNP6 was used to develop a method for quantifying the activation of accelerator components. The approach described in this paper is useful in quantifying the origin and the amount of nuclear activation.

  10. Piperlongumine inhibits atherosclerotic plaque formation and vascular smooth muscle cell proliferation by suppressing PDGF receptor signaling

    SciTech Connect

    Son, Dong Ju; Kim, Soo Yeon; Han, Seong Su; Kim, Chan Woo; Kumar, Sandeep; Park, Byeoung Soo; Lee, Sung Eun; Yun, Yeo Pyo; Jo, Hanjoong; Park, Young Hyun

    2012-10-19

    Highlights: Black-Right-Pointing-Pointer Anti-atherogenic effect of PL was examined using partial carotid ligation model in ApoE KO mice. Black-Right-Pointing-Pointer PL prevented atherosclerotic plaque development, VSMCs proliferation, and NF-{kappa}B activation. Black-Right-Pointing-Pointer Piperlongumine reduced vascular smooth muscle cell activation through PDGF-R{beta} and NF-{kappa}B-signaling. Black-Right-Pointing-Pointer PL may serve as a new therapeutic molecule for atherosclerosis treatment. -- Abstract: Piperlongumine (piplartine, PL) is an alkaloid found in the long pepper (Piper longum L.) and has well-documented anti-platelet aggregation, anti-inflammatory, and anti-cancer properties; however, the role of PL in prevention of atherosclerosis is unknown. We evaluated the anti-atherosclerotic potential of PL in an in vivo murine model of accelerated atherosclerosis and defined its mechanism of action in aortic vascular smooth muscle cells (VSMCs) in vitro. Local treatment with PL significantly reduced atherosclerotic plaque formation as well as proliferation and nuclear factor-kappa B (NF-{kappa}B) activation in an in vivo setting. PL treatment in VSMCs in vitro showed inhibition of migration and platelet-derived growth factor BB (PDGF-BB)-induced proliferation to the in vivo findings. We further identified that PL inhibited PDGF-BB-induced PDGF receptor beta activation and suppressed downstream signaling molecules such as phospholipase C{gamma}1, extracellular signal-regulated kinases 1 and 2 and Akt. Lastly, PL significantly attenuated activation of NF-{kappa}B-a downstream transcriptional regulator in PDGF receptor signaling, in response to PDGF-BB stimulation. In conclusion, our findings demonstrate a novel, therapeutic mechanism by which PL suppresses atherosclerosis plaque formation in vivo.

  11. Graphics processing unit accelerated intensity-based optical coherence tomography angiography using differential frames with real-time motion correction.

    PubMed

    Watanabe, Yuuki; Takahashi, Yuhei; Numazawa, Hiroshi

    2014-02-01

    We demonstrate intensity-based optical coherence tomography (OCT) angiography using the squared difference of two sequential frames with bulk-tissue-motion (BTM) correction. This motion correction was performed by minimization of the sum of the pixel values using axial- and lateral-pixel-shifted structural OCT images. We extract the BTM-corrected image from a total of 25 calculated OCT angiographic images. Image processing was accelerated by a graphics processing unit (GPU) with many stream processors to optimize the parallel processing procedure. The GPU processing rate was faster than that of a line scan camera (46.9 kHz). Our OCT system provides the means of displaying structural OCT images and BTM-corrected OCT angiographic images in real time.

  12. Improved laser damage threshold performance of calcium fluoride optical surfaces via Accelerated Neutral Atom Beam (ANAB) processing

    NASA Astrophysics Data System (ADS)

    Kirkpatrick, S.; Walsh, M.; Svrluga, R.; Thomas, M.

    2015-11-01

    Optics are not keeping up with the pace of laser advancements. The laser industry is rapidly increasing its power capabilities and reducing wavelengths which have exposed the optics as a weak link in lifetime failures for these advanced systems. Nanometer sized surface defects (scratches, pits, bumps and residual particles) on the surface of optics are a significant limiting factor to high end performance. Angstrom level smoothing of materials such as calcium fluoride, spinel, magnesium fluoride, zinc sulfide, LBO and others presents a unique challenge for traditional polishing techniques. Exogenesis Corporation, using its new and proprietary Accelerated Neutral Atom Beam (ANAB) technology, is able to remove nano-scale surface damage and particle contamination leaving many material surfaces with roughness typically around one Angstrom. This surface defect mitigation via ANAB processing can be shown to increase performance properties of high intensity optical materials. This paper describes the ANAB technology and summarizes smoothing results for calcium fluoride laser windows. It further correlates laser damage threshold improvements with the smoothing produced by ANAB surface treatment. All ANAB processing was performed at Exogenesis Corporation using an nAccel100TM Accelerated Particle Beam processing tool. All surface measurement data for the paper was produced via AFM analysis on a Park Model XE70 AFM, and all laser damage testing was performed at Spica Technologies, Inc. Exogenesis Corporation's ANAB processing technology is a new and unique surface modification technique that has demonstrated to be highly effective at correcting nano-scale surface defects. ANAB is a non-contact vacuum process comprised of an intense beam of accelerated, electrically neutral gas atoms with average energies of a few tens of electron volts. The ANAB process does not apply mechanical forces associated with traditional polishing techniques. ANAB efficiently removes surface

  13. Molecular Imaging of Vulnerable Atherosclerotic Plaques in Animal Models

    PubMed Central

    Gargiulo, Sara; Gramanzini, Matteo; Mancini, Marcello

    2016-01-01

    Atherosclerosis is characterized by intimal plaques of the arterial vessels that develop slowly and, in some cases, may undergo spontaneous rupture with subsequent heart attack or stroke. Currently, noninvasive diagnostic tools are inadequate to screen atherosclerotic lesions at high risk of acute complications. Therefore, the attention of the scientific community has been focused on the use of molecular imaging for identifying vulnerable plaques. Genetically engineered murine models such as ApoE−/− and ApoE−/−Fbn1C1039G+/− mice have been shown to be useful for testing new probes targeting biomarkers of relevant molecular processes for the characterization of vulnerable plaques, such as vascular endothelial growth factor receptor (VEGFR)-1, VEGFR-2, intercellular adhesion molecule (ICAM)-1, P-selectin, and integrins, and for the potential development of translational tools to identify high-risk patients who could benefit from early therapeutic interventions. This review summarizes the main animal models of vulnerable plaques, with an emphasis on genetically altered mice, and the state-of-the-art preclinical molecular imaging strategies. PMID:27618031

  14. Studies of $${\\rm Nb}_{3}{\\rm Sn}$$ Strands Based on the Restacked-Rod Process for High Field Accelerator Magnets

    DOE PAGES

    Barzi, E.; Bossert, M.; Gallo, G.; ...

    2011-12-21

    A major thrust in Fermilab's accelerator magnet R&D program is the development of Nb3Sn wires which meet target requirements for high field magnets, such as high critical current density, low effective filament size, and the capability to withstand the cabling process. The performance of a number of strands with 150/169 restack design produced by Oxford Superconducting Technology was studied for round and deformed wires. To optimize the maximum plastic strain, finite element modeling was also used as an aid in the design. Results of mechanical, transport and metallographic analyses are presented for round and deformed wires.

  15. Nuclear microscopy of atherosclerotic tissue: A review

    NASA Astrophysics Data System (ADS)

    Watt, Frank; Ren, M. Q.; Xie, J. P.; Tan, B. K. H.; Halliwell, B.

    2001-07-01

    This paper reviews the work carried out in the Research Centre for Nuclear Microscopy, NUS on the role of iron in coronary heart disease, using the technique of nuclear microscopy to determine the levels of iron and other trace elements in the artery wall and lesions. These investigations have indicated that iron may play a significant role in the development of atherosclerosis, probably through the promotion of cytotoxic free radicals leading to the oxidation of low-density lipoprotein (LDL). Using a rabbit model we have observed that early atherosclerotic lesions, induced by feeding the animals on a 1% cholesterol diet, contain increased levels of iron (up to 8 times) compared with the adjacent healthy artery wall. In a follow-up time sequence study, we have shown that iron accumulation occurs at the onset of lesion formation, which takes place around 4-6 weeks after exposure to the 1% cholesterol diet. As the lesions mature, they enlarge to occupy a significant fraction of the artery wall, and at about 16 weeks the lesions begin to show signs of calcification. In an additional experiment, where the cholesterol fed rabbits were kept anaemic through weekly bleeding, the iron content of the artery wall was reduced and the onset of atherogenesis was delayed. In a further investigation, rabbits were fed on a 1% cholesterol diet and after 6 weeks (corresponding to the period of early lesion formation) a test group was subjected to treatment using the iron chelator desferal. Preliminary results indicate that during the treatment with desferal, lesion development was slowed down.

  16. Young coconut juice can accelerate the healing process of cutaneous wounds

    PubMed Central

    2012-01-01

    Background Estrogen has been reported to accelerate cutaneous wound healing. This research studies the effect of young coconut juice (YCJ), presumably containing estrogen-like substances, on cutaneous wound healing in ovairectomized rats. Methods Four groups of female rats (6 in each group) were included in this study. These included sham-operated, ovariectomized (ovx), ovx receiving estradiol benzoate (EB) injections intraperitoneally, and ovx receiving YCJ orally. Two equidistant 1-cm full-thickness skin incisional wounds were made two weeks after ovariectomy. The rats were sacrificed at the end of the third and the fourth week of the study, and their serum estradiol (E2) level was measured by chemiluminescent immunoassay. The skin was excised and examined in histological sections stained with H&E, and immunostained using anti-estrogen receptor (ER-α an ER-β) antibodies. Results Wound healing was accelerated in ovx rats receiving YCJ, as compared to controls. This was associated with significantly higher density of immunostaining for ER-α an ER-β in keratinocytes, fibroblasts, white blood cells, fat cells, sebaceous gland, skeletal muscles, and hair shafts and follicles. This was also associated with thicker epidermis and dermis, but with thinner hypodermis. In addition, the number and size of immunoreactive hair follicles for both ER-α and ER-β were the highest in the ovx+YCJ group, as compared to the ovx+EB group. Conclusions This study demonstrates that YCJ has estrogen-like characteristics, which in turn seem to have beneficial effects on cutaneous wound healing. PMID:23234369

  17. Melatonin improves inflammation processes in liver of senescence-accelerated prone male mice (SAMP8).

    PubMed

    Cuesta, Sara; Kireev, Roman; Forman, Katherine; García, Cruz; Escames, Germaine; Ariznavarreta, Carmen; Vara, Elena; Tresguerres, Jesús A F

    2010-12-01

    Aging is associated with an increase in oxidative stress and inflammation. The aim of this study was to investigate the effect of aging on various physiological parameters related to inflammation in livers obtained from two types of male mice models: Senescence-accelerated prone (SAMP8) and senescence-accelerated-resistant (SAMR1) mice, and to study the influence of the administration of melatonin (1mg/kg/day) for one month on old SAMP8 mice on these parameters. The parameters studied have been the mRNA expression of TNF-α, iNOS, IL-1β, HO-1, HO-2, MCP1, NFkB1, NFkB2, NFkB protein or NKAP and IL-10. All have been measured by real-time reverse transcription polymerase chain reaction RT-PCR. Furthermore we analyzed the protein expression of TNF-α, iNOS, IL-1β, HO-1, HO-2, and IL-10 by Western-blot. Aging increased oxidative stress and inflammation especially in the liver of SAMP8 mice. Treatment with melatonin decreased the mRNA expression of TNF-α, IL-1β, HO (HO-1 and HO-2), iNOS, MCP1, NFκB1, NFκB2 and NKAP in old male mice. The protein expression of TNF-α, IL-1β was also decreased and IL-10 increased with melatonin treatment and no significant differences were observed in the rest of parameters analyzed. The present study showed that aging was related to inflammation in livers obtained from old male senescence prone mice (SAMP8) and old male senescence resistant mice (SAMR1) being the alterations more evident in the former. Exogenous administration of melatonin was able to reduce inflammation.

  18. Energetic ions and electrons and their acceleration processes in the magnetotail

    NASA Astrophysics Data System (ADS)

    Scholer, Manfred

    Many years of observations of energetic particle fluxes in the geomagnetic tail have shown that these particles exhibit a bursty appearance on all time scales. However, often the bursty appearance is merely due to multiple entries and exits of the spacecraft into and out of the plasma sheet which always contains varying fluxes of energetic particles. Therefore these bursts should not in each case be immediately associated with reconnection. Nevertheless the fact that charged particles are accelerated to high energies within the magnetosphere has to be explained and reconnection may ultimately be a promising candidate. In addition to these entries and exits into and out of the plasma sheet there occur short term bursts well within the plasma sheet which may be the direct signature of reconnection. At the boundary of the recovering plasma sheet earthward directed beams of energetic ions have been observed which may be due to more steady state reconnection in the distant tail. During plasma sheet dropout at substorm onset short lived (˜40 s) high energy particle bursts occur which are related to the newly created earthward neutral line. Recent results from the ISEE 3 deep tail mission have revealed the existence of fast tailward moving plasma structures which are preceded by energetic electron and ion beams. The observed velocity dispersions during the appearance of these beams allow a determination of the source location. Finally it is noted that the vast literature on energetic burst observations in the geomagnetic tail has to be contrasted with the existence of only a few theoretical papers which deal with particle acceleration to high energies during reconnection in a more quantitative way.

  19. Targeting macrophage Histone deacetylase 3 stabilizes atherosclerotic lesions

    PubMed Central

    Hoeksema, Marten A; Gijbels, Marion JJ; Van den Bossche, Jan; van der Velden, Saskia; Sijm, Ayestha; Neele, Annette E; Seijkens, Tom; Stöger, J Lauran; Meiler, Svenja; Boshuizen, Marieke CS; Dallinga-Thie, Geesje M; Levels, Johannes HM; Boon, Louis; Mullican, Shannon E; Spann, Nathanael J; Cleutjens, Jack P; Glass, Chris K; Lazar, Mitchell A; de Vries, Carlie JM; Biessen, Erik AL; Daemen, Mat JAP; Lutgens, Esther; de Winther, Menno PJ

    2014-01-01

    Macrophages are key immune cells found in atherosclerotic plaques and critically shape atherosclerotic disease development. Targeting the functional repertoire of macrophages may hold novel approaches for future atherosclerosis management. Here, we describe a previously unrecognized role of the epigenomic enzyme Histone deacetylase 3 (Hdac3) in regulating the atherosclerotic phenotype of macrophages. Using conditional knockout mice, we found that myeloid Hdac3 deficiency promotes collagen deposition in atherosclerotic lesions and thus induces a stable plaque phenotype. Also, macrophages presented a switch to anti-inflammatory wound healing characteristics and showed improved lipid handling. The pro-fibrotic phenotype was directly linked to epigenetic regulation of the Tgfb1 locus upon Hdac3 deletion, driving smooth muscle cells to increased collagen production. Moreover, in humans, HDAC3 was the sole Hdac upregulated in ruptured atherosclerotic lesions, Hdac3 associated with inflammatory macrophages, and HDAC3 expression inversely correlated with pro-fibrotic TGFB1 expression. Collectively, we show that targeting the macrophage epigenome can improve atherosclerosis outcome and we identify Hdac3 as a potential novel therapeutic target in cardiovascular disease. PMID:25007801

  20. Application of infrared fiber optic imaging in atherosclerotic plaques

    NASA Astrophysics Data System (ADS)

    Guo, Bujin; Casscells, S. W.; Bearman, Gregory H.; McNatt, Janice; Naghevi, Morteza; Malik, Basit A.; Gul, Khawar; Willerson, James T.

    1999-07-01

    Rupture of atherosclerotic plaques - the main cause of heart attach and stokes - is not predictable. Hence even treadmill stress tests fail to detect many persons at risk. Fatal plaques are found at autopsies to be associated with active inflammatory cells. Classically, inflammation is detected by its swelling, red color, pain and heat. We have found that heat accurately locates the dangerous plaques that are significantly warmer then atherosclerotic plaques without the same inflammation. In order to develop a non-surgical method of locating these plaques, an IR fiber optic imaging system has been developed in our laboratory to evalute the causes and effect of heat in atherosclerotic plaques. The fiber optical imagin bundle consists of 900 individual As2S3 chalcogenide glass fibers which transmit IR radiation from 0.7 micrometers 7 micrometers with little energy loss. By combining that with a highly sensitive Indium Antimonide IR focal plane array detector, we are able to obtain thermal graphic images in situ. The temperature heterogeneity of atherosclerotic plaques developed in the arteral of the experimental animal models is under study with the new device. The preliminary experimental results from the animal model are encouraging. The potential of using this new technology in diagnostic evaluation of the vulnerable atherosclerotic plaques is considerable.

  1. Ultrafast laser ablation for targeted atherosclerotic plaque removal

    NASA Astrophysics Data System (ADS)

    Lanvin, Thomas; Conkey, Donald B.; Descloux, Laurent; Frobert, Aurelien; Valentin, Jeremy; Goy, Jean-Jacques; Cook, Stéphane; Giraud, Marie-Noelle; Psaltis, Demetri

    2015-07-01

    Coronary artery disease, the main cause of heart disease, develops as immune cells and lipids accumulate into plaques within the coronary arterial wall. As a plaque grows, the tissue layer (fibrous cap) separating it from the blood flow becomes thinner and increasingly susceptible to rupturing and causing a potentially lethal thrombosis. The stabilization and/or treatment of atherosclerotic plaque is required to prevent rupturing and remains an unsolved medical problem. Here we show for the first time targeted, subsurface ablation of atherosclerotic plaque using ultrafast laser pulses. Excised atherosclerotic mouse aortas were ablated with ultrafast near-infrared (NIR) laser pulses. The physical damage was characterized with histological sections of the ablated atherosclerotic arteries from six different mice. The ultrafast ablation system was integrated with optical coherence tomography (OCT) imaging for plaque-specific targeting and monitoring of the resulting ablation volume. We find that ultrafast ablation of plaque just below the surface is possible without causing damage to the fibrous cap, which indicates the potential use of ultrafast ablation for subsurface atherosclerotic plaque removal. We further demonstrate ex vivo subsurface ablation of a plaque volume through a catheter device with the high-energy ultrafast pulse delivered via hollow-core photonic crystal fiber.

  2. CD44 Targeting Magnetic Glyconanoparticles for Atherosclerotic Plaque Imaging

    PubMed Central

    El-Dakdouki, Mohammad H.; El-Boubbou, Kheireddine; Kamat, Medha; Huang, Ruiping; Abela, George S.; Kiupel, Matti; Zhu, David C.; Huang, Xuefei

    2013-01-01

    Purpose The cell surface adhesion molecule CD44 plays important roles in the initiation and development of atherosclerotic plaques. We aim to develop nanoparticles that can selectively target CD44 for the non-invasive detection of atherosclerotic plaques by magnetic resonance imaging. Methods Magnetic glyco-nanoparticles with hyaluronan immobilized on the surface have been prepared. The binding of these nanoparticles with CD44 in vitro was evaluated by enzyme linked immunosorbent assay, flow cytometry and confocal microscopy. In vivo magnetic resonance imaging of plaques was performed on an atherosclerotic rabbit model. Results The magnetic glyconanoparticles can selectively bind CD44. In T2* weighted magnetic resonance images acquired in vivo, significant contrast changes in aorta walls were observed with a very low dose of the magnetic nanoparticles, allowing the detection of atherosclerotic plaques. Furthermore, imaging could be performed without significant delay after probe administration. The selectivity of hyaluronan nanoparticles in plaque imaging was established by several control experiments. Conclusions Magnetic nanoparticles bearing surface hyaluronan enabled the imaging of atherosclerotic plaques in vivo by magnetic resonance imaging. The low dose of nanoparticles required, the possibility to image without much delay and the high biocompatibility are the advantages of these nanoparticles as contrast agents for plaque imaging. PMID:23568520

  3. High shear stress induces atherosclerotic vulnerable plaque formation through angiogenesis

    PubMed Central

    Wang, Yi; Qiu, Juhui; Luo, Shisui; Xie, Xiang; Zheng, Yiming; Zhang, Kang; Ye, Zhiyi; Liu, Wanqian; Gregersen, Hans; Wang, Guixue

    2016-01-01

    Rupture of atherosclerotic plaques causing thrombosis is the main cause of acute coronary syndrome and ischemic strokes. Inhibition of thrombosis is one of the important tasks developing biomedical materials such as intravascular stents and vascular grafts. Shear stress (SS) influences the formation and development of atherosclerosis. The current review focuses on the vulnerable plaques observed in the high shear stress (HSS) regions, which localizes at the proximal region of the plaque intruding into the lumen. The vascular outward remodelling occurs in the HSS region for vascular compensation and that angiogenesis is a critical factor for HSS which induces atherosclerotic vulnerable plaque formation. These results greatly challenge the established belief that low shear stress is important for expansive remodelling, which provides a new perspective for preventing the transition of stable plaques to high-risk atherosclerotic lesions. PMID:27482467

  4. Graphics Processing Unit-Accelerated Code for Computing Second-Order Wiener Kernels and Spike-Triggered Covariance

    PubMed Central

    Mano, Omer

    2017-01-01

    Sensory neuroscience seeks to understand and predict how sensory neurons respond to stimuli. Nonlinear components of neural responses are frequently characterized by the second-order Wiener kernel and the closely-related spike-triggered covariance (STC). Recent advances in data acquisition have made it increasingly common and computationally intensive to compute second-order Wiener kernels/STC matrices. In order to speed up this sort of analysis, we developed a graphics processing unit (GPU)-accelerated module that computes the second-order Wiener kernel of a system’s response to a stimulus. The generated kernel can be easily transformed for use in standard STC analyses. Our code speeds up such analyses by factors of over 100 relative to current methods that utilize central processing units (CPUs). It works on any modern GPU and may be integrated into many data analysis workflows. This module accelerates data analysis so that more time can be spent exploring parameter space and interpreting data. PMID:28068420

  5. Developmental Changes in Processing Speed: Influence of Accelerated Education for Gifted Children

    ERIC Educational Resources Information Center

    Duan, Xiaoju; Shi, Jiannong; Zhou, Dan

    2010-01-01

    There are two major hypotheses concerning the developmental trends of processing speeds. These hypotheses explore both local and global trends. The study presented here investigates the effects of people's different knowledge on the speed with which they are able to process information. The participants in this study are gifted children aged 9,…

  6. Application of Low Level, Uniform Ultrasound Field for Acceleration of Enzymatic Bio-processing of Cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Enzymatic bio-processing of cotton generates significantly less hazardous wastewater effluents, which are readily biodegradable, but it also has several critical shortcomings that impede its acceptance by industries: expensive processing costs and slow reaction rates. Our research has found that th...

  7. Implications of acceleration environments on scaling materials processing in space to production

    NASA Technical Reports Server (NTRS)

    Demel, Ken

    1990-01-01

    Some considerations regarding materials processing in space are covered from a commercial perspective. Key areas include power, proprietary data, operational requirements (including logistics), and also the center of gravity location, and control of that location with respect to materials processing payloads.

  8. Topographic power spectral density study of the effect of surface treatment processes on niobium for superconducting radio frequency accelerator cavities

    SciTech Connect

    Charles Reece, Hui Tian, Michael Kelley, Chen Xu

    2012-04-01

    Microroughness is viewed as a critical issue for attaining optimum performance of superconducting radio frequency accelerator cavities. The principal surface smoothing methods are buffered chemical polish (BCP) and electropolish (EP). The resulting topography is characterized by atomic force microscopy (AFM). The power spectral density (PSD) of AFM data provides a more thorough description of the topography than a single-value roughness measurement. In this work, one dimensional average PSD functions derived from topography of BCP and EP with different controlled starting conditions and durations have been fitted with a combination of power law, K correlation, and shifted Gaussian models to extract characteristic parameters at different spatial harmonic scales. While the simplest characterizations of these data are not new, the systematic tracking of scale-specific roughness as a function of processing is new and offers feedback for tighter process prescriptions more knowledgably targeted at beneficial niobium topography for superconducting radio frequency applications.

  9. Accelerating solidification process simulation for large-sized system of liquid metal atoms using GPU with CUDA

    SciTech Connect

    Jie, Liang; Li, KenLi; Shi, Lin; Liu, RangSu; Mei, Jing

    2014-01-15

    Molecular dynamics simulation is a powerful tool to simulate and analyze complex physical processes and phenomena at atomic characteristic for predicting the natural time-evolution of a system of atoms. Precise simulation of physical processes has strong requirements both in the simulation size and computing timescale. Therefore, finding available computing resources is crucial to accelerate computation. However, a tremendous computational resource (GPGPU) are recently being utilized for general purpose computing due to its high performance of floating-point arithmetic operation, wide memory bandwidth and enhanced programmability. As for the most time-consuming component in MD simulation calculation during the case of studying liquid metal solidification processes, this paper presents a fine-grained spatial decomposition method to accelerate the computation of update of neighbor lists and interaction force calculation by take advantage of modern graphics processors units (GPU), enlarging the scale of the simulation system to a simulation system involving 10 000 000 atoms. In addition, a number of evaluations and tests, ranging from executions on different precision enabled-CUDA versions, over various types of GPU (NVIDIA 480GTX, 580GTX and M2050) to CPU clusters with different number of CPU cores are discussed. The experimental results demonstrate that GPU-based calculations are typically 9∼11 times faster than the corresponding sequential execution and approximately 1.5∼2 times faster than 16 CPU cores clusters implementations. On the basis of the simulated results, the comparisons between the theoretical results and the experimental ones are executed, and the good agreement between the two and more complete and larger cluster structures in the actual macroscopic materials are observed. Moreover, different nucleation and evolution mechanism of nano-clusters and nano-crystals formed in the processes of metal solidification is observed with large

  10. Accelerating solidification process simulation for large-sized system of liquid metal atoms using GPU with CUDA

    NASA Astrophysics Data System (ADS)

    Jie, Liang; Li, KenLi; Shi, Lin; Liu, RangSu; Mei, Jing

    2014-01-01

    Molecular dynamics simulation is a powerful tool to simulate and analyze complex physical processes and phenomena at atomic characteristic for predicting the natural time-evolution of a system of atoms. Precise simulation of physical processes has strong requirements both in the simulation size and computing timescale. Therefore, finding available computing resources is crucial to accelerate computation. However, a tremendous computational resource (GPGPU) are recently being utilized for general purpose computing due to its high performance of floating-point arithmetic operation, wide memory bandwidth and enhanced programmability. As for the most time-consuming component in MD simulation calculation during the case of studying liquid metal solidification processes, this paper presents a fine-grained spatial decomposition method to accelerate the computation of update of neighbor lists and interaction force calculation by take advantage of modern graphics processors units (GPU), enlarging the scale of the simulation system to a simulation system involving 10 000 000 atoms. In addition, a number of evaluations and tests, ranging from executions on different precision enabled-CUDA versions, over various types of GPU (NVIDIA 480GTX, 580GTX and M2050) to CPU clusters with different number of CPU cores are discussed. The experimental results demonstrate that GPU-based calculations are typically 9∼11 times faster than the corresponding sequential execution and approximately 1.5∼2 times faster than 16 CPU cores clusters implementations. On the basis of the simulated results, the comparisons between the theoretical results and the experimental ones are executed, and the good agreement between the two and more complete and larger cluster structures in the actual macroscopic materials are observed. Moreover, different nucleation and evolution mechanism of nano-clusters and nano-crystals formed in the processes of metal solidification is observed with large-sized system.

  11. Brightest Fermi-LAT flares of PKS 1222+216: implications on emission and acceleration processes

    SciTech Connect

    Kushwaha, Pankaj; Singh, K. P.; Sahayanathan, Sunder

    2014-11-20

    We present a high time resolution study of the two brightest γ-ray outbursts from a blazar PKS 1222+216 observed by the Fermi Large Area Telescope (LAT) in 2010. The γ-ray light curves obtained in four different energy bands, 0.1-3, 0.1-0.3, 0.3-1, and 1-3 GeV, with time bins of six hours, show asymmetric profiles with similar rise times in all the bands but a rapid decline during the April flare and a gradual one during the June flare. The light curves during the April flare show an ∼2 day long plateau in 0.1-0.3 GeV emission, erratic variations in 0.3-1 GeV emission, and a daily recurring feature in 1-3 GeV emission until the rapid rise and decline within a day. The June flare shows a monotonic rise until the peak, followed by a gradual decline powered mainly by the multi-peak 0.1-0.3 GeV emission. The peak fluxes during both the flares are similar except in the 1-3 GeV band in April, which is twice the corresponding flux during the June flare. Hardness ratios during the April flare indicate spectral hardening in the rising phase followed by softening during the decay. We attribute this behavior to the development of a shock associated with an increase in acceleration efficiency followed by its decay leading to spectral softening. The June flare suggests hardening during the rise followed by a complicated energy dependent behavior during the decay. Observed features during the June flare favor multiple emission regions while the overall flaring episode can be related to jet dynamics.

  12. A single aerobic exercise session accelerates movement execution but not central processing.

    PubMed

    Beyer, Kit B; Sage, Michael D; Staines, W Richard; Middleton, Laura E; McIlroy, William E

    2017-03-27

    Previous research has demonstrated that aerobic exercise has disparate effects on speed of processing and movement execution. In simple and choice reaction tasks, aerobic exercise appears to increase speed of movement execution while speed of processing is unaffected. In the flanker task, aerobic exercise has been shown to reduce response time on incongruent trials more than congruent trials, purportedly reflecting a selective influence on speed of processing related to cognitive control. However, it is unclear how changes in speed of processing and movement execution contribute to these exercise-induced changes in response time during the flanker task. This study examined how a single session of aerobic exercise influences speed of processing and movement execution during a flanker task using electromyography to partition response time into reaction time and movement time, respectively. Movement time decreased during aerobic exercise regardless of flanker congruence but returned to pre-exercise levels immediately after exercise. Reaction time during incongruent flanker trials decreased over time in both an aerobic exercise and non-exercise control condition indicating it was not specifically influenced by exercise. This disparate influence of aerobic exercise on movement time and reaction time indicates the importance of partitioning response time when examining the influence of aerobic exercise on speed of processing. The decrease in reaction time over time independent of aerobic exercise indicates that interpreting pre-to-post exercise changes in behavior requires caution.

  13. Linear Accelerators

    NASA Astrophysics Data System (ADS)

    Sidorin, Anatoly

    2010-01-01

    In linear accelerators the particles are accelerated by either electrostatic fields or oscillating Radio Frequency (RF) fields. Accordingly the linear accelerators are divided in three large groups: electrostatic, induction and RF accelerators. Overview of the different types of accelerators is given. Stability of longitudinal and transverse motion in the RF linear accelerators is briefly discussed. The methods of beam focusing in linacs are described.

  14. Monte Carlo-based fluorescence molecular tomography reconstruction method accelerated by a cluster of graphic processing units.

    PubMed

    Quan, Guotao; Gong, Hui; Deng, Yong; Fu, Jianwei; Luo, Qingming

    2011-02-01

    High-speed fluorescence molecular tomography (FMT) reconstruction for 3-D heterogeneous media is still one of the most challenging problems in diffusive optical fluorescence imaging. In this paper, we propose a fast FMT reconstruction method that is based on Monte Carlo (MC) simulation and accelerated by a cluster of graphics processing units (GPUs). Based on the Message Passing Interface standard, we modified the MC code for fast FMT reconstruction, and different Green's functions representing the flux distribution in media are calculated simultaneously by different GPUs in the cluster. A load-balancing method was also developed to increase the computational efficiency. By applying the Fréchet derivative, a Jacobian matrix is formed to reconstruct the distribution of the fluorochromes using the calculated Green's functions. Phantom experiments have shown that only 10 min are required to get reconstruction results with a cluster of 6 GPUs, rather than 6 h with a cluster of multiple dual opteron CPU nodes. Because of the advantages of high accuracy and suitability for 3-D heterogeneity media with refractive-index-unmatched boundaries from the MC simulation, the GPU cluster-accelerated method provides a reliable approach to high-speed reconstruction for FMT imaging.

  15. Monte Carlo-based fluorescence molecular tomography reconstruction method accelerated by a cluster of graphic processing units

    NASA Astrophysics Data System (ADS)

    Quan, Guotao; Gong, Hui; Deng, Yong; Fu, Jianwei; Luo, Qingming

    2011-02-01

    High-speed fluorescence molecular tomography (FMT) reconstruction for 3-D heterogeneous media is still one of the most challenging problems in diffusive optical fluorescence imaging. In this paper, we propose a fast FMT reconstruction method that is based on Monte Carlo (MC) simulation and accelerated by a cluster of graphics processing units (GPUs). Based on the Message Passing Interface standard, we modified the MC code for fast FMT reconstruction, and different Green's functions representing the flux distribution in media are calculated simultaneously by different GPUs in the cluster. A load-balancing method was also developed to increase the computational efficiency. By applying the Fréchet derivative, a Jacobian matrix is formed to reconstruct the distribution of the fluorochromes using the calculated Green's functions. Phantom experiments have shown that only 10 min are required to get reconstruction results with a cluster of 6 GPUs, rather than 6 h with a cluster of multiple dual opteron CPU nodes. Because of the advantages of high accuracy and suitability for 3-D heterogeneity media with refractive-index-unmatched boundaries from the MC simulation, the GPU cluster-accelerated method provides a reliable approach to high-speed reconstruction for FMT imaging.

  16. A graphics processing unit accelerated motion correction algorithm and modular system for real-time fMRI.

    PubMed

    Scheinost, Dustin; Hampson, Michelle; Qiu, Maolin; Bhawnani, Jitendra; Constable, R Todd; Papademetris, Xenophon

    2013-07-01

    Real-time functional magnetic resonance imaging (rt-fMRI) has recently gained interest as a possible means to facilitate the learning of certain behaviors. However, rt-fMRI is limited by processing speed and available software, and continued development is needed for rt-fMRI to progress further and become feasible for clinical use. In this work, we present an open-source rt-fMRI system for biofeedback powered by a novel Graphics Processing Unit (GPU) accelerated motion correction strategy as part of the BioImage Suite project ( www.bioimagesuite.org ). Our system contributes to the development of rt-fMRI by presenting a motion correction algorithm that provides an estimate of motion with essentially no processing delay as well as a modular rt-fMRI system design. Using empirical data from rt-fMRI scans, we assessed the quality of motion correction in this new system. The present algorithm performed comparably to standard (non real-time) offline methods and outperformed other real-time methods based on zero order interpolation of motion parameters. The modular approach to the rt-fMRI system allows the system to be flexible to the experiment and feedback design, a valuable feature for many applications. We illustrate the flexibility of the system by describing several of our ongoing studies. Our hope is that continuing development of open-source rt-fMRI algorithms and software will make this new technology more accessible and adaptable, and will thereby accelerate its application in the clinical and cognitive neurosciences.

  17. NREL Develops Accelerated Sample Activation Process for Hydrogen Storage Materials (Fact Sheet)

    SciTech Connect

    Not Available

    2010-12-01

    This fact sheet describes NREL's accomplishments in developing a new sample activation process that reduces the time to prepare samples for measurement of hydrogen storage from several days to five minutes and provides more uniform samples. Work was performed by NREL's Chemical and Materials Science Center.

  18. Single-step affinity purification of enzyme biotherapeutics: a platform methodology for accelerated process development.

    PubMed

    Brower, Kevin P; Ryakala, Venkat K; Bird, Ryan; Godawat, Rahul; Riske, Frank J; Konstantinov, Konstantin; Warikoo, Veena; Gamble, Jean

    2014-01-01

    Downstream sample purification for quality attribute analysis is a significant bottleneck in process development for non-antibody biologics. Multi-step chromatography process train purifications are typically required prior to many critical analytical tests. This prerequisite leads to limited throughput, long lead times to obtain purified product, and significant resource requirements. In this work, immunoaffinity purification technology has been leveraged to achieve single-step affinity purification of two different enzyme biotherapeutics (Fabrazyme® [agalsidase beta] and Enzyme 2) with polyclonal and monoclonal antibodies, respectively, as ligands. Target molecules were rapidly isolated from cell culture harvest in sufficient purity to enable analysis of critical quality attributes (CQAs). Most importantly, this is the first study that demonstrates the application of predictive analytics techniques to predict critical quality attributes of a commercial biologic. The data obtained using the affinity columns were used to generate appropriate models to predict quality attributes that would be obtained after traditional multi-step purification trains. These models empower process development decision-making with drug substance-equivalent product quality information without generation of actual drug substance. Optimization was performed to ensure maximum target recovery and minimal target protein degradation. The methodologies developed for Fabrazyme were successfully reapplied for Enzyme 2, indicating platform opportunities. The impact of the technology is significant, including reductions in time and personnel requirements, rapid product purification, and substantially increased throughput. Applications are discussed, including upstream and downstream process development support to achieve the principles of Quality by Design (QbD) as well as integration with bioprocesses as a process analytical technology (PAT).

  19. Fluorescence lifetime imaging microscopy for the characterization of atherosclerotic plaques

    NASA Astrophysics Data System (ADS)

    Phipps, Jennifer; Sun, Yinghua; Saroufeem, Ramez; Hatami, Nisa; Marcu, Laura

    2009-02-01

    Atherosclerotic plaque composition has been associated with plaque instability and rupture. This study investigates the use of fluorescence lifetime imaging microscopy (FLIM) for mapping plaque composition and assessing features of vulnerability. Measurements were conducted in atherosclerotic human aortic samples using an endoscopic FLIM system (spatial resolution of 35 µm temporal resolution 200 ps) developed in our lab which allows mapping in one measurement the composition within a volume of 4 mm diameter x 250 µm depth. Each pixel in the image represents a corresponding fluorescence lifetime value; images are formed through a flexible 0.6 mm side-viewing imaging bundle which allows for further intravascular applications. Based on previously recorded spectra of human atherosclerotic plaque, fluorescence emission was collected through two filters: f1: 377/50 and f2: 460/60 (center wavelength/bandwidth), which together provides the greatest discrimination between intrinsic fluorophores related to plaque vulnerability. We have imaged nine aortas and lifetime images were retrieved using a Laguerre expansion deconvolution technique and correlated with histopathology. Early results demonstrate discrimination using fluorescence lifetime between early, lipid-rich, and collagen-rich lesions which are consistent with previously reported time-resolved atherosclerotic plaque measurements.

  20. In vivo determination of arterial collagen synthesis in atherosclerotic rabbits

    SciTech Connect

    Opsahl, W.P.; DeLuca, D.J.; Ehrhart, L.A.

    1986-03-01

    Collagen and non-collagen protein synthesis rates were determined in vivo in tissues from rabbits fed a control or atherogenic diet supplemented with 2% peanut oil and 0.25% cholesterol for 4 months. Rabbits received a bolus intravenous injection of L-(/sup 3/H)-proline (1.0 mCi/kg) and unlabeled L-proline (7 mmoles/kg) in 0.9% NaCl. Plasma proline specific activity decreased only 20% over 5 hr and was similar to the specific activity of free proline in tissues. Thoracic aortas from atherosclerotic rabbits exhibited raised plaques covering at least 75% of the surface. Thoracic intima plus a portion of the media (TIM) was separated from the remaining media plus adventitia (TMA). Dry delipidated weight, total collagen content, and collagen as a percent of dry weight were increased significantly in the TIM of atherosclerotic rabbits. Collagen synthesis rates and collagen synthesis as a percent of total protein synthesis were likewise increased both in the TIM and in the abdominal aortas. No differences from controls either in collagen content or collagen synthesis rates were observed in the TMA, lung or skin. These results demonstrate for the first time in vivo that formation of atherosclerotic plaques is associated with increased rates of collagen synthesis. Furthermore, as previously observed with incubations in vitro, collagen synthesis was elevated to a greater extent than noncollagen protein synthesis in atherosclerotic aortas from rabbits fed cholesterol plus peanut oil.

  1. Cap buckling as a potential mechanism of atherosclerotic plaque vulnerability.

    PubMed

    Abdelali, Maria; Reiter, Steven; Mongrain, Rosaire; Bertrand, Michel; L'Allier, Philippe L; Kritikou, Ekaterini A; Tardif, Jean-Claude

    2014-04-01

    Plaque rupture in atherosclerosis is the primary cause of potentially deadly coronary events, yet about 40% of ruptures occur away from the plaque cap shoulders and cannot be fully explained with the current biomechanical theories. Here, cap buckling is considered as a potential destabilizing factor which increases the propensity of the atherosclerotic plaque to rupture and which may also explain plaque failure away from the cap shoulders. To investigate this phenomenon, quasistatic 2D finite element simulations are performed, considering the salient geometrical and nonlinear material properties of diverse atherosclerotic plaques over the range of physiological loads. The numerical results indicate that buckling may displace the location of the peak von Mises stresses in the deflected caps. Plaque buckling, together with its deleterious effects is further observed experimentally in plaque caps using a physical model of deformable mock coronary arteries with fibroatheroma. Moreover, an analytical approach combining quasistatic equilibrium equations with the Navier-Bresse formulas is used to demonstrate the buckling potential of a simplified arched slender cap under intraluminal pressure and supported by foundations. This analysis shows that plaque caps - calcified, fibrotic or cellular - may buckle in specific undulated shapes once submitted to critical loads. Finally, a preliminary analysis of intravascular ultrasonography recordings of patients with atherosclerotic coronary arteries corroborates the numerical, experimental and theoretical findings and shows that various plaque caps buckle in vivo. By displacing the sites of high stresses in the plaque cap, buckling may explain the atherosclerotic plaque cap rupture at various locations, including cap shoulders.

  2. Atherosclerotic changes of vessels caused by restriction of movement

    NASA Technical Reports Server (NTRS)

    Gvishiani, G. S.; Kobakhidze, N. G.; Mchedlishvili, M. G.; Dekanosidze, T. I.

    1980-01-01

    The effect of restriction of movement on the development of atheroscelerosis was studied in rabbits. Drastic restriction of movement for 20 and 30 days causes atherosclerotic alterations of the aorta and shifts in ECG which are characteristic of coronary atherosclerosis. At the same time, shortening of the duration of blood coagulation and an increase in the content of catecholamines and beta-lipoproteids occur.

  3. Antiinflammatory actions of inorganic nitrate stabilize the atherosclerotic plaque

    PubMed Central

    Khambata, Rayomand S.; Ghosh, Suborno M.; Rathod, Krishnaraj S.; Thevathasan, Tharssana; Filomena, Federica; Xiao, Qingzhong; Ahluwalia, Amrita

    2017-01-01

    Reduced bioavailable nitric oxide (NO) plays a key role in the enhanced leukocyte recruitment reflective of systemic inflammation thought to precede and underlie atherosclerotic plaque formation and instability. Recent evidence demonstrates that inorganic nitrate (NO3−) through sequential chemical reduction in vivo provides a source of NO that exerts beneficial effects upon the cardiovascular system, including reductions in inflammatory responses. We tested whether the antiinflammatory effects of inorganic nitrate might prove useful in ameliorating atherosclerotic disease in Apolipoprotein (Apo)E knockout (KO) mice. We show that dietary nitrate treatment, although having no effect upon total plaque area, caused a reduction in macrophage accumulation and an elevation in smooth muscle accumulation within atherosclerotic plaques of ApoE KO mice, suggesting plaque stabilization. We also show that in nitrate-fed mice there is reduced systemic leukocyte rolling and adherence, circulating neutrophil numbers, neutrophil CD11b expression, and myeloperoxidase activity compared with wild-type littermates. Moreover, we show in both the ApoE KO mice and using an acute model of inflammation that this effect upon neutrophils results in consequent reductions in inflammatory monocyte expression that is associated with elevations of the antiinflammatory cytokine interleukin (IL)-10. In summary, we demonstrate that inorganic nitrate suppresses acute and chronic inflammation by targeting neutrophil recruitment and that this effect, at least in part, results in consequent reductions in the inflammatory status of atheromatous plaque, and suggest that this effect may have clinical utility in the prophylaxis of inflammatory atherosclerotic disease. PMID:28057862

  4. Denoising NMR time-domain signal by singular-value decomposition accelerated by graphics processing units.

    PubMed

    Man, Pascal P; Bonhomme, Christian; Babonneau, Florence

    2014-01-01

    We present a post-processing method that decreases the NMR spectrum noise without line shape distortion. As a result the signal-to-noise (S/N) ratio of a spectrum increases. This method is called Cadzow enhancement procedure that is based on the singular-value decomposition of time-domain signal. We also provide software whose execution duration is a few seconds for typical data when it is executed in modern graphic-processing unit. We tested this procedure not only on low sensitive nucleus (29)Si in hybrid materials but also on low gyromagnetic ratio, quadrupole nucleus (87)Sr in reference sample Sr(NO3)2. Improving the spectrum S/N ratio facilitates the determination of T/Q ratio of hybrid materials. It is also applicable to simulated spectrum, resulting shorter simulation duration for powder averaging. An estimation of the number of singular values needed for denoising is also provided.

  5. [Acceleration of osmotic dehydration process through ohmic heating of foods: raspberries (Rubus idaeus)].

    PubMed

    Simpson, Ricardo R; Jiménez, Maite P; Carevic, Erica G; Grancelli, Romina M

    2007-06-01

    Raspberries (Rubus idaeus) were osmotically dehydrated by applying a conventional method under the supposition of a homogeneous solution, all in a 62% glucose solution at 50 degrees C. Raspberries (Rubus idaeus) were also osmotically dehydrated by using ohmic heating in a 57% glucose solution at a variable voltage (to maintain temperature between 40 and 50 degrees C) and an electric field intensity <100 V/cm. When comparing the results from both experiments it was evident that processing time is reduced when ohmic heating technique was used. In some cases this reduction reached even 50%. This is explained by the additional effect to the thermal damage that is generated in an ohmic process, denominated electroporation.

  6. Data Streaming for Metabolomics: Accelerating Data Processing and Analysis from Days to Minutes

    PubMed Central

    2016-01-01

    The speed and throughput of analytical platforms has been a driving force in recent years in the “omics” technologies and while great strides have been accomplished in both chromatography and mass spectrometry, data analysis times have not benefited at the same pace. Even though personal computers have become more powerful, data transfer times still represent a bottleneck in data processing because of the increasingly complex data files and studies with a greater number of samples. To meet the demand of analyzing hundreds to thousands of samples within a given experiment, we have developed a data streaming platform, XCMS Stream, which capitalizes on the acquisition time to compress and stream recently acquired data files to data processing servers, mimicking just-in-time production strategies from the manufacturing industry. The utility of this XCMS Online-based technology is demonstrated here in the analysis of T cell metabolism and other large-scale metabolomic studies. A large scale example on a 1000 sample data set demonstrated a 10 000-fold time savings, reducing data analysis time from days to minutes. Further, XCMS Stream has the capability to increase the efficiency of downstream biochemical dependent data acquisition (BDDA) analysis by initiating data conversion and data processing on subsets of data acquired, expanding its application beyond data transfer to smart preliminary data decision-making prior to full acquisition. PMID:27983788

  7. Asymmetric neighborhood functions accelerate ordering process of self-organizing maps

    SciTech Connect

    Ota, Kaiichiro; Aoki, Takaaki; Kurata, Koji; Aoyagi, Toshio

    2011-02-15

    A self-organizing map (SOM) algorithm can generate a topographic map from a high-dimensional stimulus space to a low-dimensional array of units. Because a topographic map preserves neighborhood relationships between the stimuli, the SOM can be applied to certain types of information processing such as data visualization. During the learning process, however, topological defects frequently emerge in the map. The presence of defects tends to drastically slow down the formation of a globally ordered topographic map. To remove such topological defects, it has been reported that an asymmetric neighborhood function is effective, but only in the simple case of mapping one-dimensional stimuli to a chain of units. In this paper, we demonstrate that even when high-dimensional stimuli are used, the asymmetric neighborhood function is effective for both artificial and real-world data. Our results suggest that applying the asymmetric neighborhood function to the SOM algorithm improves the reliability of the algorithm. In addition, it enables processing of complicated, high-dimensional data by using this algorithm.

  8. Asymmetric neighborhood functions accelerate ordering process of self-organizing maps

    NASA Astrophysics Data System (ADS)

    Ota, Kaiichiro; Aoki, Takaaki; Kurata, Koji; Aoyagi, Toshio

    2011-02-01

    A self-organizing map (SOM) algorithm can generate a topographic map from a high-dimensional stimulus space to a low-dimensional array of units. Because a topographic map preserves neighborhood relationships between the stimuli, the SOM can be applied to certain types of information processing such as data visualization. During the learning process, however, topological defects frequently emerge in the map. The presence of defects tends to drastically slow down the formation of a globally ordered topographic map. To remove such topological defects, it has been reported that an asymmetric neighborhood function is effective, but only in the simple case of mapping one-dimensional stimuli to a chain of units. In this paper, we demonstrate that even when high-dimensional stimuli are used, the asymmetric neighborhood function is effective for both artificial and real-world data. Our results suggest that applying the asymmetric neighborhood function to the SOM algorithm improves the reliability of the algorithm. In addition, it enables processing of complicated, high-dimensional data by using this algorithm.

  9. Data Streaming for Metabolomics: Accelerating Data Processing and Analysis from Days to Minutes.

    PubMed

    Montenegro-Burke, J Rafael; Aisporna, Aries E; Benton, H Paul; Rinehart, Duane; Fang, Mingliang; Huan, Tao; Warth, Benedikt; Forsberg, Erica; Abe, Brian T; Ivanisevic, Julijana; Wolan, Dennis W; Teyton, Luc; Lairson, Luke; Siuzdak, Gary

    2017-01-17

    The speed and throughput of analytical platforms has been a driving force in recent years in the "omics" technologies and while great strides have been accomplished in both chromatography and mass spectrometry, data analysis times have not benefited at the same pace. Even though personal computers have become more powerful, data transfer times still represent a bottleneck in data processing because of the increasingly complex data files and studies with a greater number of samples. To meet the demand of analyzing hundreds to thousands of samples within a given experiment, we have developed a data streaming platform, XCMS Stream, which capitalizes on the acquisition time to compress and stream recently acquired data files to data processing servers, mimicking just-in-time production strategies from the manufacturing industry. The utility of this XCMS Online-based technology is demonstrated here in the analysis of T cell metabolism and other large-scale metabolomic studies. A large scale example on a 1000 sample data set demonstrated a 10 000-fold time savings, reducing data analysis time from days to minutes. Further, XCMS Stream has the capability to increase the efficiency of downstream biochemical dependent data acquisition (BDDA) analysis by initiating data conversion and data processing on subsets of data acquired, expanding its application beyond data transfer to smart preliminary data decision-making prior to full acquisition.

  10. Basic Electropolishing Process Research and Development in Support of Improved Reliable Performance SRF Cavities for the Future Accelerator

    SciTech Connect

    H. Tian, C.E. Reece,M.J. Kelley

    2009-05-01

    Future accelerators require unprecedented cavity performance, which is strongly influenced by interior surface nanosmoothness. Electropolishing is the technique of choice to be developed for high-field superconducting radiofrequency cavities. Electrochemical impedance spectroscopy (EIS) and related techniques point to the electropolishing mechanism of Nb in a sulfuric and hydrofluoric acid electrolyte of controlled by a compact surface salt film under F- diffusion-limited mass transport control. These and other findings are currently guiding a systematic characterization to form the basis for cavity process optimization, such as flowrate, electrolyte composition and temperature. This integrated analysis is expected to provide optimum EP parameter sets for a controlled, reproducible and uniform surface leveling for Nb SRF cavities.

  11. PRIME process: an alternative to multiple layer resist systems and high accelerating voltage for e-beam lithography

    NASA Astrophysics Data System (ADS)

    Tedesco, Serge V.; Pierrat, Christophe; Vinet, Francoise; Florin, Brigitte; Lerme, Michel; Guibert, Jean C.

    1990-05-01

    A new positive working system for e-beam lithography, called PRIME (Positive Resist IMage by dry Etching) is proposed. High contrast (about 6) and resolution 75 nm L/S in O.351um thick resist are achieved. Very steep profiles can be obtai- ned on thick resist even at low accelerating voltage as O.2pm hole in l.2pm thick resist at 20 keV. To be able to quantify both intra and inter proximity effect on positive tone resist specific two layers electric tests chips were designed. Then PRIME process has been compared, in terms of proximity effects magnitude, at 20kV and 50 kV, to RAY-PF resist show- ing clearly advantages over such three components novolac ba- sed positive resist.

  12. Multidisciplinary Simulation Acceleration using Multiple Shared-Memory Graphical Processing Units

    NASA Astrophysics Data System (ADS)

    Kemal, Jonathan Yashar

    For purposes of optimizing and analyzing turbomachinery and other designs, the unsteady Favre-averaged flow-field differential equations for an ideal compressible gas can be solved in conjunction with the heat conduction equation. We solve all equations using the finite-volume multiple-grid numerical technique, with the dual time-step scheme used for unsteady simulations. Our numerical solver code targets CUDA-capable Graphical Processing Units (GPUs) produced by NVIDIA. Making use of MPI, our solver can run across networked compute notes, where each MPI process can use either a GPU or a Central Processing Unit (CPU) core for primary solver calculations. We use NVIDIA Tesla C2050/C2070 GPUs based on the Fermi architecture, and compare our resulting performance against Intel Zeon X5690 CPUs. Solver routines converted to CUDA typically run about 10 times faster on a GPU for sufficiently dense computational grids. We used a conjugate cylinder computational grid and ran a turbulent steady flow simulation using 4 increasingly dense computational grids. Our densest computational grid is divided into 13 blocks each containing 1033x1033 grid points, for a total of 13.87 million grid points or 1.07 million grid points per domain block. To obtain overall speedups, we compare the execution time of the solver's iteration loop, including all resource intensive GPU-related memory copies. Comparing the performance of 8 GPUs to that of 8 CPUs, we obtain an overall speedup of about 6.0 when using our densest computational grid. This amounts to an 8-GPU simulation running about 39.5 times faster than running than a single-CPU simulation.

  13. Audit Report on "Waste Processing and Recovery Act Acceleration Efforts for Contact-Handled Transuranic Waste at the Hanford Site"

    SciTech Connect

    2010-05-01

    The Department of Energy's Office of Environmental Management's (EM), Richland Operations Office (Richland), is responsible for disposing of the Hanford Site's (Hanford) transuranic (TRU) waste, including nearly 12,000 cubic meters of radioactive contact-handled TRU wastes. Prior to disposing of this waste at the Department's Waste Isolation Pilot Plant (WIPP), Richland must certify that it meets WIPP's waste acceptance criteria. To be certified, the waste must be characterized, screened for prohibited items, treated (if necessary) and placed into a satisfactory disposal container. In a February 2008 amendment to an existing Record of Decision (Decision), the Department announced its plan to ship up to 8,764 cubic meters of contact-handled TRU waste from Hanford and other waste generator sites to the Advanced Mixed Waste Treatment Project (AMWTP) at Idaho's National Laboratory (INL) for processing and certification prior to disposal at WIPP. The Department decided to maximize the use of the AMWTP's automated waste processing capabilities to compact and, thereby, reduce the volume of contact-handled TRU waste. Compaction reduces the number of shipments and permits WIPP to more efficiently use its limited TRU waste disposal capacity. The Decision noted that the use of AMWTP would avoid the time and expense of establishing a processing capability at other sites. In May 2009, EM allocated $229 million of American Recovery and Reinvestment Act of 2009 (Recovery Act) funds to support Hanford's Solid Waste Program, including Hanford's contact-handled TRU waste. Besides providing jobs, these funds were intended to accelerate cleanup in the short term. We initiated this audit to determine whether the Department was effectively using Recovery Act funds to accelerate processing of Hanford's contact-handled TRU waste. Relying on the availability of Recovery Act funds, the Department changed course and approved an alternative plan that could increase costs by about $25 million

  14. Emerging techniques for assisting and accelerating food freezing processes: A review of recent research progresses.

    PubMed

    Cheng, Lina; Sun, Da-Wen; Zhu, Zhiwei; Zhang, Zi

    2017-03-04

    Freezing plays an important role in food preservation and the emergence of rapid freezing technologies can be highly beneficial to the food industry. This paper reviews some novel food freezing technologies, including high-pressure freezing (HPF), ultrasound-assisted freezing (UAF), electrically disturbed freezing (EF) and magnetically disturbed freezing (MF), microwave-assisted freezing (MWF), and osmo-dehydro-freezing (ODF). HPF and UAF can initiate ice nucleation rapidly, leading to uniform distribution of ice crystals and the control of their size and shape. Specifically, the former is focused on increasing the degree of supercooling, whereas the latter aims to decrease it. Direct current electric freezing (DC-EF) and alternating current electric freezing (AC-EF) exhibit different effects on ice nucleation. DC-EF can promote ice nucleation and AC-EF has the opposite effect. Furthermore, ODF has been successfully used for freezing various vegetables and fruit. MWF cannot control the nucleation temperature, but can decrease supercooling degree, thus decreasing the size of ice crystals. The heat and mass transfer processes during ODF have been investigated experimentally and modeled mathematically. More studies should be carried out to understand the effects of these technologies on food freezing process.

  15. The "step feature" of suprathermal ion distributions: a discriminator between acceleration processes?

    NASA Astrophysics Data System (ADS)

    Fahr, H. J.; Fichtner, H.

    2012-09-01

    The discussion of exactly which process is causing the preferred build-up of v-5-power law tails of the velocity distribution of suprathermal particles in the solar wind is still ongoing. Criteria allowing one to discriminate between the various suggestions that have been made would be useful in order to clarify the physics behind these tails. With this study, we draw the attention to the so-called "step feature" of the velocity distributions and offer a criterion that allows one to distinguish between those scenarios that employ velocity diffusion, i.e. second-order Fermi processes, which are prime candidates in the present debate. With an analytical approximation to the self-consistently obtained velocity diffusion coefficient, we solve the transport equation for suprathermal particles. The numerical simulation reveals that this form of the diffusion coefficient naturally leads to the step feature of the velocity distributions. This finding favours - at least in regions of the appearance of the step feature (i.e. for heliocentric distances up to about 11 AU and at lower energies) - the standard velocity diffusion as a consequence of the particle's interactions with the plasma wave turbulence as opposed to that caused by velocity fluctuation-induced compressions and rarefactions.

  16. Influence of processing procedure on the quality of Radix Scrophulariae: a quantitative evaluation of the main compounds obtained by accelerated solvent extraction and high-performance liquid chromatography.

    PubMed

    Cao, Gang; Wu, Xin; Li, Qinglin; Cai, Hao; Cai, Baochang; Zhu, Xuemei

    2015-02-01

    An improved high-performance liquid chromatography with diode array detection combined with accelerated solvent extraction method was used to simultaneously determine six compounds in crude and processed Radix Scrophulariae samples. Accelerated solvent extraction parameters such as extraction solvent, temperature, number of cycles, and analysis procedure were systematically optimized. The results indicated that compared with crude Radix Scrophulariae samples, the processed samples had lower contents of harpagide and harpagoside but higher contents of catalpol, acteoside, angoroside C, and cinnamic acid. The established method was sufficiently rapid and reliable for the global quality evaluation of crude and processed herbal medicines.

  17. Accelerators and the Accelerator Community

    SciTech Connect

    Malamud, Ernest; Sessler, Andrew

    2008-06-01

    In this paper, standing back--looking from afar--and adopting a historical perspective, the field of accelerator science is examined. How it grew, what are the forces that made it what it is, where it is now, and what it is likely to be in the future are the subjects explored. Clearly, a great deal of personal opinion is invoked in this process.

  18. Can Accelerators Accelerate Learning?

    NASA Astrophysics Data System (ADS)

    Santos, A. C. F.; Fonseca, P.; Coelho, L. F. S.

    2009-03-01

    The 'Young Talented' education program developed by the Brazilian State Funding Agency (FAPERJ) [1] makes it possible for high-schools students from public high schools to perform activities in scientific laboratories. In the Atomic and Molecular Physics Laboratory at Federal University of Rio de Janeiro (UFRJ), the students are confronted with modern research tools like the 1.7 MV ion accelerator. Being a user-friendly machine, the accelerator is easily manageable by the students, who can perform simple hands-on activities, stimulating interest in physics, and getting the students close to modern laboratory techniques.

  19. PARTICLE ACCELERATOR

    DOEpatents

    Teng, L.C.

    1960-01-19

    ABS>A combination of two accelerators, a cyclotron and a ring-shaped accelerator which has a portion disposed tangentially to the cyclotron, is described. Means are provided to transfer particles from the cyclotron to the ring accelerator including a magnetic deflector within the cyclotron, a magnetic shield between the ring accelerator and the cyclotron, and a magnetic inflector within the ring accelerator.

  20. Natural ageing process accelerates the release of Ag from functional textile in various exposure scenarios

    NASA Astrophysics Data System (ADS)

    Ding, Dahu; Chen, Lulu; Dong, Shaowei; Cai, Hao; Chen, Jifei; Jiang, Canlan; Cai, Tianming

    2016-11-01

    Natural ageing process occurs throughout the life cycle of textile products, which may possess influences on the release behavior of additives such as silver nanoparticles (Ag NPs). In this study, we assessed the releasability of Ag NPs from a Ag NPs functionalized textile in five different exposure scenarios (i.e. tap water (TW), pond water (PW), rain water (RW), artificial sweat (AS), and detergent solution (DS) along with deionized water (DW) as reference), which were very likely to occur throughout the life cycle of the textile. For the pristine textile, although the most remarkable release was found in DW (6–15 μg Ag/g textile), the highest release rate was found in RW (around 7 μg Ag/(g textile·h)). After ageing treatment, the total released Ag could be increased by 75.7~386.0% in DW, AS and DS. Morphological analysis clearly showed that the Ag NPs were isolated from the surface of the textile fibre due to the ageing treatment. This study provides useful information for risk assessment of nano-enhanced textile products.

  1. Accelerating electrostatic surface potential calculation with multi-scale approximation on graphics processing units.

    PubMed

    Anandakrishnan, Ramu; Scogland, Tom R W; Fenley, Andrew T; Gordon, John C; Feng, Wu-chun; Onufriev, Alexey V

    2010-06-01

    Tools that compute and visualize biomolecular electrostatic surface potential have been used extensively for studying biomolecular function. However, determining the surface potential for large biomolecules on a typical desktop computer can take days or longer using currently available tools and methods. Two commonly used techniques to speed-up these types of electrostatic computations are approximations based on multi-scale coarse-graining and parallelization across multiple processors. This paper demonstrates that for the computation of electrostatic surface potential, these two techniques can be combined to deliver significantly greater speed-up than either one separately, something that is in general not always possible. Specifically, the electrostatic potential computation, using an analytical linearized Poisson-Boltzmann (ALPB) method, is approximated using the hierarchical charge partitioning (HCP) multi-scale method, and parallelized on an ATI Radeon 4870 graphical processing unit (GPU). The implementation delivers a combined 934-fold speed-up for a 476,040 atom viral capsid, compared to an equivalent non-parallel implementation on an Intel E6550 CPU without the approximation. This speed-up is significantly greater than the 42-fold speed-up for the HCP approximation alone or the 182-fold speed-up for the GPU alone.

  2. Accelerated evaluation of the robustness of treatment plans against geometric uncertainties by Gaussian processes.

    PubMed

    Sobotta, B; Söhn, M; Alber, M

    2012-12-07

    In order to provide a consistently high quality treatment, it is of great interest to assess the robustness of a treatment plan under the influence of geometric uncertainties. One possible method to implement this is to run treatment simulations for all scenarios that may arise from these uncertainties. These simulations may be evaluated in terms of the statistical distribution of the outcomes (as given by various dosimetric quality metrics) or statistical moments thereof, e.g. mean and/or variance. This paper introduces a method to compute the outcome distribution and all associated values of interest in a very efficient manner. This is accomplished by substituting the original patient model with a surrogate provided by a machine learning algorithm. This Gaussian process (GP) is trained to mimic the behavior of the patient model based on only very few samples. Once trained, the GP surrogate takes the place of the patient model in all subsequent calculations.The approach is demonstrated on two examples. The achieved computational speedup is more than one order of magnitude.

  3. Natural ageing process accelerates the release of Ag from functional textile in various exposure scenarios

    PubMed Central

    Ding, Dahu; Chen, Lulu; Dong, Shaowei; Cai, Hao; Chen, Jifei; Jiang, Canlan; Cai, Tianming

    2016-01-01

    Natural ageing process occurs throughout the life cycle of textile products, which may possess influences on the release behavior of additives such as silver nanoparticles (Ag NPs). In this study, we assessed the releasability of Ag NPs from a Ag NPs functionalized textile in five different exposure scenarios (i.e. tap water (TW), pond water (PW), rain water (RW), artificial sweat (AS), and detergent solution (DS) along with deionized water (DW) as reference), which were very likely to occur throughout the life cycle of the textile. For the pristine textile, although the most remarkable release was found in DW (6–15 μg Ag/g textile), the highest release rate was found in RW (around 7 μg Ag/(g textile·h)). After ageing treatment, the total released Ag could be increased by 75.7~386.0% in DW, AS and DS. Morphological analysis clearly showed that the Ag NPs were isolated from the surface of the textile fibre due to the ageing treatment. This study provides useful information for risk assessment of nano-enhanced textile products. PMID:27869136

  4. Accelerating Electrostatic Surface Potential Calculation with Multiscale Approximation on Graphics Processing Units

    PubMed Central

    Anandakrishnan, Ramu; Scogland, Tom R. W.; Fenley, Andrew T.; Gordon, John C.; Feng, Wu-chun; Onufriev, Alexey V.

    2010-01-01

    Tools that compute and visualize biomolecular electrostatic surface potential have been used extensively for studying biomolecular function. However, determining the surface potential for large biomolecules on a typical desktop computer can take days or longer using currently available tools and methods. Two commonly used techniques to speed up these types of electrostatic computations are approximations based on multi-scale coarse-graining and parallelization across multiple processors. This paper demonstrates that for the computation of electrostatic surface potential, these two techniques can be combined to deliver significantly greater speed-up than either one separately, something that is in general not always possible. Specifically, the electrostatic potential computation, using an analytical linearized Poisson Boltzmann (ALPB) method, is approximated using the hierarchical charge partitioning (HCP) multiscale method, and parallelized on an ATI Radeon 4870 graphical processing unit (GPU). The implementation delivers a combined 934-fold speed-up for a 476,040 atom viral capsid, compared to an equivalent non-parallel implementation on an Intel E6550 CPU without the approximation. This speed-up is significantly greater than the 42-fold speed-up for the HCP approximation alone or the 182-fold speed-up for the GPU alone. PMID:20452792

  5. Rock varnish in New York: An accelerated snapshot of accretionary processes

    NASA Astrophysics Data System (ADS)

    Krinsley, David H.; Dorn, Ronald I.; DiGregorio, Barry E.; Langworthy, Kurt A.; Ditto, Jeffrey

    2012-02-01

    Samples of manganiferous rock varnish collected from fluvial, bedrock outcrop and Erie Barge Canal settings in New York state host a variety of diatom, fungal and bacterial microbial forms that are enhanced in manganese and iron. Use of a Dual-Beam Focused Ion Beam Scanning Electron Microscope to manipulate the varnish in situ reveals microbial forms that would not have otherwise been identified. The relative abundance of Mn-Fe-enriched biotic forms in New York samples is far greater than varnishes collected from warm deserts. Moisture availability has long been noted as a possible control on varnish growth rates, a hypothesis consistent with the greater abundance of Mn-enhancing bioforms. Sub-micron images of incipient varnish formation reveal that varnishing in New York probably starts with the mortality of microorganisms that enhanced Mn on bare mineral surfaces; microbial death results in the adsorption of the Mn-rich sheath onto the rock in the form of filamentous networks. Clay minerals are then cemented by remobilization of the Mn-rich material. Thus, the previously unanswered question of what comes first - clay mineral deposition or enhancement of Mn - can be answered in New York because of the faster rate of varnish growth. In contrast, very slow rates of varnishing seen in warm deserts, of microns per thousand years, make it less likely that collected samples will reveal varnish accretionary processes than samples collected from fast-accreting moist settings.

  6. Graphic processing unit accelerated real-time partially coherent beam generator

    NASA Astrophysics Data System (ADS)

    Ni, Xiaolong; Liu, Zhi; Chen, Chunyi; Jiang, Huilin; Fang, Hanhan; Song, Lujun; Zhang, Su

    2016-07-01

    A method of using liquid-crystals (LCs) to generate a partially coherent beam in real-time is described. An expression for generating a partially coherent beam is given and calculated using a graphic processing unit (GPU), i.e., the GeForce GTX 680. A liquid-crystal on silicon (LCOS) with 256 × 256 pixels is used as the partially coherent beam generator (PCBG). An optimizing method with partition convolution is used to improve the generating speed of our LC PCBG. The total time needed to generate a random phase map with a coherence width range from 0.015 mm to 1.5 mm is less than 2.4 ms for calculation and readout with the GPU; adding the time needed for the CPU to read and send to LCOS with the response time of the LC PCBG, the real-time partially coherent beam (PCB) generation frequency of our LC PCBG is up to 312 Hz. To our knowledge, it is the first real-time partially coherent beam generator. A series of experiments based on double pinhole interference are performed. The result shows that to generate a laser beam with a coherence width of 0.9 mm and 1.5 mm, with a mean error of approximately 1%, the RMS values needed 0.021306 and 0.020883 and the PV values required 0.073576 and 0.072998, respectively.

  7. Natural ageing process accelerates the release of Ag from functional textile in various exposure scenarios.

    PubMed

    Ding, Dahu; Chen, Lulu; Dong, Shaowei; Cai, Hao; Chen, Jifei; Jiang, Canlan; Cai, Tianming

    2016-11-21

    Natural ageing process occurs throughout the life cycle of textile products, which may possess influences on the release behavior of additives such as silver nanoparticles (Ag NPs). In this study, we assessed the releasability of Ag NPs from a Ag NPs functionalized textile in five different exposure scenarios (i.e. tap water (TW), pond water (PW), rain water (RW), artificial sweat (AS), and detergent solution (DS) along with deionized water (DW) as reference), which were very likely to occur throughout the life cycle of the textile. For the pristine textile, although the most remarkable release was found in DW (6-15 μg Ag/g textile), the highest release rate was found in RW (around 7 μg Ag/(g textile·h)). After ageing treatment, the total released Ag could be increased by 75.7~386.0% in DW, AS and DS. Morphological analysis clearly showed that the Ag NPs were isolated from the surface of the textile fibre due to the ageing treatment. This study provides useful information for risk assessment of nano-enhanced textile products.

  8. Serum-Sphingosine-1-Phosphate Concentrations Are Inversely Associated with Atherosclerotic Diseases in Humans

    PubMed Central

    Geissen, Markus; Schwedhelm, Edzard; Winkler, Martin S.; Geffken, Maria; Peine, Sven; Schoen, Gerhard; Debus, E. Sebastian; Larena-Avellaneda, Axel; Daum, Guenter

    2016-01-01

    Background and Objectives Atherosclerotic changes of arteries are the leading cause for deaths in cardiovascular disease and greatly impair patient’s quality of life. Sphingosine-1-phosphate (S1P) is a signaling sphingolipid that regulates potentially pro-as well as anti-atherogenic processes. Here, we investigate whether serum-S1P concentrations are associated with peripheral artery disease (PAD) and carotid stenosis (CS). Methods and Results Serum was sampled from blood donors (controls, N = 174) and from atherosclerotic patients (N = 132) who presented to the hospital with either clinically relevant PAD (N = 102) or CS (N = 30). From all subjects, serum-S1P was measured by mass spectrometry and blood parameters were determined by routine laboratory assays. When compared to controls, atherosclerotic patients before invasive treatment to restore blood flow showed significantly lower serum-S1P levels. This difference cannot be explained by risk factors for atherosclerosis (old age, male gender, hypertension, hypercholesteremia, obesity, diabetes or smoking) or comorbidities (Chronic obstructive pulmonary disease, kidney insufficiency or arrhythmia). Receiver operating characteristic curves suggest that S1P has more power to indicate atherosclerosis (PAD and CS) than high density lipoprotein-cholesterol (HDL-C). In 35 patients, serum-S1P was measured again between one and six months after treatment. In this group, serum-S1P concentrations rose after treatment independent of whether patients had PAD or CS, or whether they underwent open or endovascular surgery. Post-treatment S1P levels were highly associated to platelet numbers measured pre-treatment. Conclusions Our study shows that PAD and CS in humans is associated with decreased serum-S1P concentrations and that S1P may possess higher accuracy to indicate these diseases than HDL-C. PMID:27973607

  9. Grid-based algorithm to search critical points, in the electron density, accelerated by graphics processing units.

    PubMed

    Hernández-Esparza, Raymundo; Mejía-Chica, Sol-Milena; Zapata-Escobar, Andy D; Guevara-García, Alfredo; Martínez-Melchor, Apolinar; Hernández-Pérez, Julio-M; Vargas, Rubicelia; Garza, Jorge

    2014-12-05

    Using a grid-based method to search the critical points in electron density, we show how to accelerate such a method with graphics processing units (GPUs). When the GPU implementation is contrasted with that used on central processing units (CPUs), we found a large difference between the time elapsed by both implementations: the smallest time is observed when GPUs are used. We tested two GPUs, one related with video games and other used for high-performance computing (HPC). By the side of the CPUs, two processors were tested, one used in common personal computers and other used for HPC, both of last generation. Although our parallel algorithm scales quite well on CPUs, the same implementation on GPUs runs around 10× faster than 16 CPUs, with any of the tested GPUs and CPUs. We have found what one GPU dedicated for video games can be used without any problem for our application, delivering a remarkable performance, in fact; this GPU competes against one HPC GPU, in particular when single-precision is used.

  10. Mass transport perspective on an accelerated exclusion process: Analysis of augmented current and unit-velocity phases

    NASA Astrophysics Data System (ADS)

    Dong, Jiajia; Klumpp, Stefan; Zia, R. K. P.

    2013-02-01

    In an accelerated exclusion process (AEP), each particle can “hop” to its adjacent site if empty as well as “kick” the frontmost particle when joining a cluster of size ℓ⩽ℓmax. With various choices of the interaction range, ℓmax, we find that the steady state of AEP can be found in a homogeneous phase with augmented currents (AC) or a segregated phase with holes moving at unit velocity (UV). Here we present a detailed study on the emergence of the novel phases, from two perspectives: the AEP and a mass transport process (MTP). In the latter picture, the system in the UV phase is composed of a condensate in coexistence with a fluid, while the transition from AC to UV can be regarded as condensation. Using Monte Carlo simulations, exact results for special cases, and analytic methods in a mean field approach (within the MTP), we focus on steady state currents and cluster sizes. Excellent agreement between data and theory is found, providing an insightful picture for understanding this model system.

  11. Mass transport perspective on an accelerated exclusion process: analysis of augmented current and unit-velocity phases.

    PubMed

    Dong, Jiajia; Klumpp, Stefan; Zia, R K P

    2013-02-01

    In an accelerated exclusion process (AEP), each particle can "hop" to its adjacent site if empty as well as "kick" the frontmost particle when joining a cluster of size ℓ≤ℓ(max). With various choices of the interaction range, ℓ(max), we find that the steady state of AEP can be found in a homogeneous phase with augmented currents (AC) or a segregated phase with holes moving at unit velocity (UV). Here we present a detailed study on the emergence of the novel phases, from two perspectives: the AEP and a mass transport process (MTP). In the latter picture, the system in the UV phase is composed of a condensate in coexistence with a fluid, while the transition from AC to UV can be regarded as condensation. Using Monte Carlo simulations, exact results for special cases, and analytic methods in a mean field approach (within the MTP), we focus on steady state currents and cluster sizes. Excellent agreement between data and theory is found, providing an insightful picture for understanding this model system.

  12. Genome-wide analysis of LXRα activation reveals new transcriptional networks in human atherosclerotic foam cells.

    PubMed

    Feldmann, Radmila; Fischer, Cornelius; Kodelja, Vitam; Behrens, Sarah; Haas, Stefan; Vingron, Martin; Timmermann, Bernd; Geikowski, Anne; Sauer, Sascha

    2013-04-01

    Increased physiological levels of oxysterols are major risk factors for developing atherosclerosis and cardiovascular disease. Lipid-loaded macrophages, termed foam cells, are important during the early development of atherosclerotic plaques. To pursue the hypothesis that ligand-based modulation of the nuclear receptor LXRα is crucial for cell homeostasis during atherosclerotic processes, we analysed genome-wide the action of LXRα in foam cells and macrophages. By integrating chromatin immunoprecipitation-sequencing (ChIP-seq) and gene expression profile analyses, we generated a highly stringent set of 186 LXRα target genes. Treatment with the nanomolar-binding ligand T0901317 and subsequent auto-regulatory LXRα activation resulted in sequence-dependent sharpening of the genome-binding patterns of LXRα. LXRα-binding loci that correlated with differential gene expression revealed 32 novel target genes with potential beneficial effects, which in part explained the implications of disease-associated genetic variation data. These observations identified highly integrated LXRα ligand-dependent transcriptional networks, including the APOE/C1/C4/C2-gene cluster, which contribute to the reversal of cholesterol efflux and the dampening of inflammation processes in foam cells to prevent atherogenesis.

  13. Systemic Atherosclerotic Inflammation Following Acute Myocardial Infarction: Myocardial Infarction Begets Myocardial Infarction

    PubMed Central

    Joshi, Nikhil V; Toor, Iqbal; Shah, Anoop S V; Carruthers, Kathryn; Vesey, Alex T; Alam, Shirjel R; Sills, Andrew; Hoo, Teng Y; Melville, Adam J; Langlands, Sarah P; Jenkins, William S A; Uren, Neal G; Mills, Nicholas L; Fletcher, Alison M; van Beek, Edwin J R; Rudd, James H F; Fox, Keith A A; Dweck, Marc R; Newby, David E

    2015-01-01

    Background Preclinical data suggest that an acute inflammatory response following myocardial infarction (MI) accelerates systemic atherosclerosis. Using combined positron emission and computed tomography, we investigated whether this phenomenon occurs in humans. Methods and Results Overall, 40 patients with MI and 40 with stable angina underwent thoracic 18F-fluorodeoxyglucose combined positron emission and computed tomography scan. Radiotracer uptake was measured in aortic atheroma and nonvascular tissue (paraspinal muscle). In 1003 patients enrolled in the Global Registry of Acute Coronary Events, we assessed whether infarct size predicted early (≤30 days) and late (>30 days) recurrent coronary events. Compared with patients with stable angina, patients with MI had higher aortic 18F-fluorodeoxyglucose uptake (tissue-to-background ratio 2.15±0.30 versus 1.84±0.18, P<0.0001) and plasma C-reactive protein concentrations (6.50 [2.00 to 12.75] versus 2.00 [0.50 to 4.00] mg/dL, P=0.0005) despite having similar aortic (P=0.12) and less coronary (P=0.006) atherosclerotic burden and similar paraspinal muscular 18F-fluorodeoxyglucose uptake (P=0.52). Patients with ST-segment elevation MI had larger infarcts (peak plasma troponin 32 300 [10 200 to >50 000] versus 3800 [1000 to 9200] ng/L, P<0.0001) and greater aortic 18F-fluorodeoxyglucose uptake (2.24±0.32 versus 2.02±0.21, P=0.03) than those with non–ST-segment elevation MI. Peak plasma troponin concentrations correlated with aortic 18F-fluorodeoxyglucose uptake (r=0.43, P=0.01) and, on multivariate analysis, independently predicted early (tertile 3 versus tertile 1: relative risk 4.40 [95% CI 1.90 to 10.19], P=0.001), but not late, recurrent MI. Conclusions The presence and extent of MI is associated with increased aortic atherosclerotic inflammation and early recurrent MI. This finding supports the hypothesis that acute MI exacerbates systemic atherosclerotic inflammation and remote plaque destabilization

  14. Effect of accelerated electron beam on mechanical properties of human cortical bone: influence of different processing methods.

    PubMed

    Kaminski, Artur; Grazka, Ewelina; Jastrzebska, Anna; Marowska, Joanna; Gut, Grzegorz; Wojciechowski, Artur; Uhrynowska-Tyszkiewicz, Izabela

    2012-08-01

    Accelerated electron beam (EB) irradiation has been a sufficient method used for sterilisation of human tissue grafts for many years in a number of tissue banks. Accelerated EB, in contrast to more often used gamma photons, is a form of ionizing radiation that is characterized by lower penetration, however it is more effective in producing ionisation and to reach the same level of sterility, the exposition time of irradiated product is shorter. There are several factors, including dose and temperature of irradiation, processing conditions, as well as source of irradiation that may influence mechanical properties of a bone graft. The purpose of this study was to evaluate the effect e-beam irradiation with doses of 25 or 35 kGy, performed on dry ice or at ambient temperature, on mechanical properties of non-defatted or defatted compact bone grafts. Left and right femurs from six male cadaveric donors, aged from 46 to 54 years, were transversely cut into slices of 10 mm height, parallel to the longitudinal axis of the bone. Compact bone rings were assigned to the eight experimental groups according to the different processing method (defatted or non-defatted), as well as e-beam irradiation dose (25 or 35 kGy) and temperature conditions of irradiation (ambient temperature or dry ice). Axial compression testing was performed with a material testing machine. Results obtained for elastic and plastic regions of stress-strain curves examined by univariate analysis are described. Based on multivariate analysis, including all groups, it was found that temperature of e-beam irradiation and defatting had no consistent significant effect on evaluated mechanical parameters of compact bone rings. In contrast, irradiation with both doses significantly decreased the ultimate strain and its derivative toughness, while not affecting the ultimate stress (bone strength). As no deterioration of mechanical properties was observed in the elastic region, the reduction of the energy

  15. Laser acceleration

    NASA Astrophysics Data System (ADS)

    Tajima, T.; Nakajima, K.; Mourou, G.

    2017-02-01

    The fundamental idea of Laser Wakefield Acceleration (LWFA) is reviewed. An ultrafast intense laser pulse drives coherent wakefield with a relativistic amplitude robustly supported by the plasma. While the large amplitude of wakefields involves collective resonant oscillations of the eigenmode of the entire plasma electrons, the wake phase velocity ˜ c and ultrafastness of the laser pulse introduce the wake stability and rigidity. A large number of worldwide experiments show a rapid progress of this concept realization toward both the high-energy accelerator prospect and broad applications. The strong interest in this has been spurring and stimulating novel laser technologies, including the Chirped Pulse Amplification, the Thin Film Compression, the Coherent Amplification Network, and the Relativistic Mirror Compression. These in turn have created a conglomerate of novel science and technology with LWFA to form a new genre of high field science with many parameters of merit in this field increasing exponentially lately. This science has triggered a number of worldwide research centers and initiatives. Associated physics of ion acceleration, X-ray generation, and astrophysical processes of ultrahigh energy cosmic rays are reviewed. Applications such as X-ray free electron laser, cancer therapy, and radioisotope production etc. are considered. A new avenue of LWFA using nanomaterials is also emerging.

  16. Automatic classification of atherosclerotic plaques imaged with intravascular OCT

    PubMed Central

    Rico-Jimenez, Jose J.; Campos-Delgado, Daniel U.; Villiger, Martin; Otsuka, Kenichiro; Bouma, Brett E.; Jo, Javier A.

    2016-01-01

    Intravascular optical coherence tomography (IV-OCT) allows evaluation of atherosclerotic plaques; however, plaque characterization is performed by visual assessment and requires a trained expert for interpretation of the large data sets. Here, we present a novel computational method for automated IV-OCT plaque characterization. This method is based on the modeling of each A-line of an IV-OCT data set as a linear combination of a number of depth profiles. After estimating these depth profiles by means of an alternating least square optimization strategy, they are automatically classified to predefined tissue types based on their morphological characteristics. The performance of our proposed method was evaluated with IV-OCT scans of cadaveric human coronary arteries and corresponding tissue histopathology. Our results suggest that this methodology allows automated identification of fibrotic and lipid-containing plaques. Moreover, this novel computational method has the potential to enable high throughput atherosclerotic plaque characterization. PMID:27867716

  17. Intravascular photoacoustic tomography for characterization of atherosclerotic lipid and inflammation

    NASA Astrophysics Data System (ADS)

    Zhang, Jian; Qin, Huan; Shi, Yujiao; Yang, Sihua; Xing, Da

    2014-09-01

    Photoacoustic imaging is a fast growing imaging technology depending on its high optical resolution of optics while taking the advantage of the high penetration depth of ultrasound. In this paper, we demonstrate the new progress in the photoacoustic imaging. Atherosclerosis is characterized by a progressive build-up of lipid in the arterial wall, which is known as plaque. Histological studies demonstrate that the primary cause of acute cardiovascular events is the rupture of atherosclerotic plaques. Lipid and inflammation within the plaque are related to influence the propensity of plaques to disrupt. Photoacoustic intravascular tomography (IVPAT) holds a great advantage in providing comprehensive morphological and functional information of plaques. Lipid relative concentration maps of atherosclerotic aorta were obtained and compared with histology. Furthermore, by selectively targeting the intravascular inflammatory cytokines, IVPAT is also capable of mapping the inflamed area and determining the degree of inflammation.

  18. EMITTING ELECTRONS SPECTRA AND ACCELERATION PROCESSES IN THE JET OF Mrk 421: FROM THE LOW STATE TO THE GIANT FLARE STATE

    SciTech Connect

    Yan Dahai; Zhang Li; Fan Zhonghui; Zeng Houdun; Yuan Qiang

    2013-03-10

    We investigate the electron energy distributions (EEDs) and the acceleration processes in the jet of Mrk 421 through fitting the spectral energy distributions (SEDs) in different active states in the frame of a one-zone synchrotron self-Compton model. After assuming two possible EEDs formed in different acceleration models: the shock-accelerated power law with exponential cut-off (PLC) EED and the stochastic-turbulence-accelerated log-parabolic (LP) EED, we fit the observed SEDs of Mrk 421 in both low and giant flare states using the Markov Chain Monte Carlo method which constrains the model parameters in a more efficient way. The results from our calculations indicate that (1) the PLC and LP models give comparably good fits for the SED in the low state, but the variations of model parameters from low state to flaring can be reasonably explained only in the case of the PLC in the low state; and (2) the LP model gives better fits compared to the PLC model for the SED in the flare state, and the intra-day/night variability observed at GeV-TeV bands can be accommodated only in the LP model. The giant flare may be attributed to the stochastic turbulence re-acceleration of the shock-accelerated electrons in the low state. Therefore, we may conclude that shock acceleration is dominant in the low state, while stochastic turbulence acceleration is dominant in the flare state. Moreover, our result shows that the extrapolated TeV spectra from the best-fit SEDs from optical through GeV with the two EEDs are different. It should be considered with caution when such extrapolated TeV spectra are used to constrain extragalactic background light models.

  19. Two-tank suspended growth process for accelerating the detoxification kinetics of hydrocarbons requiring initial monooxygenation reactions.

    PubMed

    Dahlen, Elizabeth P; Rittmann, Bruce E

    2002-01-01

    An experimental evaluation demonstrated that suspended growth systems operated in a two-tank accelerator/aerator configuration significantly increased the overall removal rates for phenol and 2,4-dichlorophenol (2,4-DCP), aromatic hydrocarbons that require initial monooxygenations. The accelerator tank is a small volume that receives the influent and recycled biomass. It has a high ratio of electron donor (BOD) to electron acceptor (O2). Biomass in the accelerator should be enriched in reduced nicotinamide adenine dinucleotide (NADH + H+) and have a very high specific growth rate, conditions that should accelerate the kinetics of monooxygenation reactions. For the more slowly degraded 2,4-DCP, the average percentage removal increased from 74% to 93%, even though the volume of the two-tank system was smaller than that of the one-tank system in most experiments. The average volumetric and biomass-specific removal rates increased by 50% and 100%, respectively, in the two-tank system, compared to a one-tank system. The greatest enhancement in 2,4-DCP removal occurred when the accelerator tank comprised approximately 20% of the system volume. Biomass in the accelerator tank was significantly enriched in NADH + H+ when its dissolved oxygen (DO) concentration was below 0.25 mg/L, a situation having a high ratio of donor to acceptor. The accelerator biomass had its highest NADH + H+ content for the experiments that had the highest rate of 2,4-DCP removal. Biomass in the accelerator also had a much higher specific growth rate than in the aerator or the system overall, and the specific growth rate in the accelerator was inversely correlated to the accelerator volume.

  20. From Lipids to Inflammation: New Approaches to Reducing Atherosclerotic Risk.

    PubMed

    Shapiro, Michael D; Fazio, Sergio

    2016-02-19

    The introduction of statins ≈ 30 years ago ushered in the era of lipid lowering as the most effective way to reduce risk of atherosclerotic cardiovascular disease. Nonetheless, residual risk remains high, and statin intolerance is frequently encountered in clinical practice. After a long dry period, the field of therapeutics targeted to lipids and atherosclerosis has entered a renaissance. Moreover, the demonstration of clinical benefits from the addition of ezetimibe to statin therapy in subjects with acute coronary syndromes has renewed the enthusiasm for the cholesterol hypothesis and the hope that additional agents that lower low-density lipoprotein will decrease risk of atherosclerotic cardiovascular disease. Drugs in the orphan disease category are now available for patients with the most extreme hypercholesterolemia. Furthermore, discovery and rapid translation of a novel biological pathway has given rise to a new class of cholesterol-lowering drugs, the proprotein convertase subtilisin kexin-9 inhibitors. Trials of niacin added to statin have failed to demonstrate cardiac benefits, and 3 cholesterol ester transfer protein inhibitors have also failed to reduce atherosclerotic cardiovascular disease risk, despite producing substantial increases in HDL levels. Although the utility of triglyceride-lowering therapies remains uncertain, 2 large clinical trials are testing the influence of omega-3 polyunsaturated fatty acids on atherosclerotic events in hypertriglyceridemia. Novel antisense therapies targeting apolipoprotein C-III (for triglyceride reduction) and apo(a) (for lipoprotein(a) reduction) are showing a promising trajectory. Finally, 2 large clinical trials are formally putting the inflammatory hypothesis of atherosclerosis to the test and may open a new avenue for cardiovascular disease risk reduction.

  1. Macrophage-targeted photodynamic detection of vulnerable atherosclerotic plaque

    NASA Astrophysics Data System (ADS)

    Hamblin, Michael R.; Tawakol, Ahmed; Castano, Ana P.; Gad, Faten; Zahra, Touqir; Ahmadi, Atosa; Stern, Jeremy; Ortel, Bernhard; Chirico, Stephanie; Shirazi, Azadeh; Syed, Sakeena; Muller, James E.

    2003-06-01

    Rupture of a vulnerable atherosclerotic plaque (VP) leading to coronary thrombosis is the chief cause of sudden cardiac death. VPs are angiographically insignificant lesions, which are excessively inflamed and characterized by dense macrophage infiltration, large necrotic lipid cores, thin fibrous caps, and paucity of smooth muscle cells. We have recently shown that chlorin(e6) conjugated with maleylated albumin can target macrophages with high selectivity via the scavenger receptor. We report the potential of this macrophage-targeted fluorescent probe to localize in VPs in a rabbit model of atherosclerosis, and allow detection and/or diagnosis by fluorescence spectroscopy or imaging. Atherosclerotic lesions were induced in New Zealand White rabbit aortas by balloon injury followed by administration of a high-fat diet. 24-hours after IV injection of the conjugate into atherosclerotic or normal rabbits, the animals were sacrificed, and aortas were removed, dissected and examined for fluorescence localization in plaques by fiber-based spectrofluorimetry and confocal microscopy. Dye uptake within the aortas was also quantified by fluorescence extraction of samples from aorta segments. Biodistribution of the dye was studied in many organs of the rabbits. Surface spectrofluorimetry after conjugate injection was able to distinguish between plaque and adjacent aorta, between atherosclerotic and normal aorta, and balloon-injured and normal iliac arteries with high significance. Discrete areas of high fluorescence (up to 20 times control were detected in the balloon-injured segments, presumably corresponding to macrophage-rich plaques. Confocal microscopy showed red ce6 fluorescence localized in plaques that showed abundant foam cells and macrophages by histology. Extraction data on aortic tissue corroborated the selectivity of the conjugate for plaques. These data support the strategy of employing macrophage-targeted fluorescent dyes to detect VP by intravascular

  2. Vulnerable atherosclerotic plaque detection by resonance Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Liu, Cheng-hui; Boydston-White, Susie; Weisberg, Arel; Wang, Wubao; Sordillo, Laura A.; Perotte, Adler; Tomaselli, Vincent P.; Sordillo, Peter P.; Pei, Zhe; Shi, Lingyan; Alfano, Robert R.

    2016-12-01

    A clear correlation has been observed between the resonance Raman (RR) spectra of plaques in the aortic tunica intimal wall of a human corpse and three states of plaque evolution: fibrolipid plaques, calcified and ossified plaques, and vulnerable atherosclerotic plaques (VPs). These three states of atherosclerotic plaque lesions demonstrated unique RR molecular fingerprints from key molecules, rendering their spectra unique with respect to one another. The vibrational modes of lipids, cholesterol, carotenoids, tryptophan and heme proteins, the amide I, II, III bands, and methyl/methylene groups from the intrinsic atherosclerotic VPs in tissues were studied. The salient outcome of the investigation was demonstrating the correlation between RR measurements of VPs and the thickness measurements of fibrous caps on VPs using standard histopathology methods, an important metric in evaluating the stability of a VP. The RR results show that VPs undergo a structural change when their caps thin to 66 μm, very close to the 65-μm empirical medical definition of a thin cap fibroatheroma plaque, the most unstable type of VP.

  3. High speed intravascular photoacoustic imaging of atherosclerotic arteries (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Piao, Zhonglie; Ma, Teng; Qu, Yueqiao; Li, Jiawen; Yu, Mingyue; He, Youmin; Shung, K. Kirk; Zhou, Qifa; Kim, Chang-Seok; Chen, Zhongping

    2016-02-01

    Cardiovascular disease is the leading cause of death in the industrialized nations. Accurate quantification of both the morphology and composition of lipid-rich vulnerable atherosclerotic plaque are essential for early detection and optimal treatment in clinics. In previous works, intravascular photoacoustic (IVPA) imaging for detection of lipid-rich plaque within coronary artery walls has been demonstrated in ex vivo, but the imaging speed is still limited. In order to increase the imaging speed, a high repetition rate laser is needed. In this work, we present a high speed integrated IVPA/US imaging system with a 500 Hz optical parametric oscillator laser at 1725 nm. A miniature catheter with 1.0 mm outer diameter was designed with a 200 μm multimode fiber and an ultrasound transducer with 45 MHz center frequency. The fiber was polished at 38 degree and enclosed in a glass capillary for total internal reflection. An optical/electrical rotary junction and pull-back mechanism was applied for rotating and linearly scanning the catheter to obtain three-dimensional imaging. Atherosclerotic rabbit abdominal aorta was imaged as two frame/second at 1725 nm. Furthermore, by wide tuning range of the laser wavelength from 1680 nm to 1770 nm, spectroscopic photoacoustic analysis of lipid-mimicking phantom and an human atherosclerotic artery was performed ex vivo. The results demonstrated that the developed IVPA/US imaging system is capable for high speed intravascular imaging for plaque detection.

  4. Artery buckling affects the mechanical stress in atherosclerotic plaques

    PubMed Central

    2015-01-01

    Background Tortuous arteries are often seen in patients with hypertension and atherosclerosis. While the mechanical stress in atherosclerotic plaque under lumen pressure has been studied extensively, the mechanical stability of atherosclerotic arteries and subsequent effect on the plaque stress remain unknown. To this end, we investigated the buckling and post-buckling behavior of model stenotic coronary arteries with symmetric and asymmetric plaque. Methods Buckling analysis for a model coronary artery with symmetric and asymmetric plaque was conducted using finite element analysis based on the dimensions and nonlinear anisotropic materials properties reported in the literature. Results Artery with asymmetric plaque had lower critical buckling pressure compared to the artery with symmetric plaque and control artery. Buckling increased the peak stress in the plaque and led to the development of a high stress concentration in artery with asymmetric plaque. Stiffer calcified tissue and severe stenosis increased the critical buckling pressure of the artery with asymmetric plaque. Conclusions Arteries with atherosclerotic plaques are prone to mechanical buckling which leads to a high stress concentration in the plaques that can possibly make the plaques prone to rupture. PMID:25603490

  5. Stress analysis of fracture of atherosclerotic plaques: crack propagation modeling.

    PubMed

    Rezvani-Sharif, Alireza; Tafazzoli-Shadpour, Mohammad; Kazemi-Saleh, Davood; Sotoudeh-Anvari, Maryam

    2016-12-09

    Traditionally, the degree of luminal obstruction has been used to assess the vulnerability of atherosclerotic plaques. However, recent studies have revealed that other factors such as plaque morphology, material properties of lesion components and blood pressure may contribute to the fracture of atherosclerotic plaques. The aim of this study was to investigate the mechanism of fracture of atherosclerotic plaques based on the mechanical stress distribution and fatigue analysis by means of numerical simulation. Realistic models of type V plaques were reconstructed based on histological images. Finite element method was used to determine mechanical stress distribution within the plaque. Assuming that crack propagation initiated at the sites of stress concentration, crack propagation due to pulsatile blood pressure was modeled. Results showed that crack propagation considerably changed the stress field within the plaque and in some cases led to initiation of secondary cracks. The lipid pool stiffness affected the location of crack formation and the rate and direction of crack propagation. Moreover, increasing the mean or pulse pressure decreased the number of cycles to rupture. It is suggested that crack propagation analysis can lead to a better recognition of factors involved in plaque rupture and more accurate determination of vulnerable plaques.

  6. Practice comparisons between accelerated resolution therapy, eye movement desensitization and reprocessing and cognitive processing therapy with case examples.

    PubMed

    Hernandez, Diego F; Waits, Wendi; Calvio, Lisseth; Byrne, Mary

    2016-12-01

    Recent outcomes for Cognitive Processing Therapy (CPT) and Prolonged Exposure (PE) therapy indicate that as many as 60-72% of patients retain their PTSD diagnosis after treatment with CPT or PE. One emerging therapy with the potential to augment existing trauma focused therapies is Accelerated Resolution Therapy (ART). ART is currently being used along with evidence based approaches at Fort Belvoir Community Hospital and by report has been both positive for clients as well as less taxing on professionals trained in ART. The following is an in-practice theoretical comparison of CPT, EMDR and ART with case examples from Fort Belvoir Community Hospital. While all three approaches share common elements and interventions, ART distinguishes itself through emphasis on the rescripting of traumatic events and the brevity of the intervention. While these case reports are not part of a formal study, they suggest that ART has the potential to augment and enhance the current delivery methods of mental health care in military environments.

  7. Expression of ACAT-1 protein in human atherosclerotic lesions and cultured human monocytes-macrophages.

    PubMed

    Miyazaki, A; Sakashita, N; Lee, O; Takahashi, K; Horiuchi, S; Hakamata, H; Morganelli, P M; Chang, C C; Chang, T Y

    1998-10-01

    The acyl coenzyme A:cholesterol acyltransferase (ACAT) gene was first cloned in 1993 (Chang et al, J Biol Chem. 1993;268:20747-20755; designated ACAT-1). Using affinity-purified antibodies raised against the N-terminal portion of human ACAT-1 protein, we performed immunohistochemical localization studies and showed that the ACAT-1 protein was highly expressed in atherosclerotic lesions of the human aorta. We also performed cell-specific localization studies using double immunostaining and showed that ACAT-1 was predominantly expressed in macrophages but not in smooth muscle cells. We then used a cell culture system in vitro to monitor the ACAT-1 expression in differentiating monocytes-macrophages. The ACAT-1 protein content increased by up to 10-fold when monocytes spontaneously differentiated into macrophages. This increase occurred within the first 2 days of culturing the monocytes and reached a plateau level within 4 days of culturing, indicating that the increase in ACAT-1 protein content is an early event during the monocyte differentiation process. The ACAT-1 protein expressed in the differentiating monocytes-macrophages was shown to be active by enzyme assay in vitro. The high levels of ACAT-1 present in macrophages maintained in culture can explain the high ACAT-1 contents found in atherosclerotic lesions. Our results thus support the idea that ACAT-1 plays an important role in differentiating monocytes and in forming macrophage foam cells during the development of human atherosclerosis.

  8. Automatic atherosclerotic heart disease detection in intracoronary optical coherence tomography images.

    PubMed

    Xu, Mengdi; Cheng, Jun; Wong, Damon Wing Kee; Taruya, Akira; Tanaka, Atsushi; Liu, Jiang

    2014-01-01

    Intracoronary optical coherence tomography (OCT) is a new invasive imaging system which produces high-resolution images of coronary arteries. Preliminary data suggests that the atherosclerotic disease can be detected from the intracoronary OCT images. However, manual assessment of the intracoronary OCT images is time-consuming and subjective. In this work, we present an automatic atherosclerotic disease detection system on intracoronary OCT images. In the system, a preprocessing scheme is first applied to remove speckle noise and artifacts caused by catheter. Intensity, Histograms of Oriented Gradients (HOG), and Local Binary Patterns (LBP) are then extracted to represent the OCT image. Finally a linear SVM classifier is employed to detect the unhealthy subject. Four-fold cross-validation process is conducted to evaluate the proposed system; and a dataset with 200 images from healthy subjects and 200 images from unhealthy subjects is built to evaluate the system. The mean accuracy is 0.90 and standard deviation is 0.0427, which indicates that the proposed system is accurate and stable.

  9. Endovascular Management of Atherosclerotic Renal Artery Stenosis: Post-Cardiovascular Outcomes in Renal Atherosclerotic Lesions Era Winner or False Alarm?

    PubMed Central

    Karanikola, Evridiki; Karaolanis, Georgios; Galyfos, George; Barbaressos, Emmanuel; Palla, Viktoria; Filis, Konstantinos

    2017-01-01

    Renal artery stenosis (RAS) is frequently associated with severe comorbidities such as reduced renal perfusion, hypertension, and end-stage renal failure. In approximately 90% of patients, renal artery atherosclerosis is the main cause for RAS, and it is associated with an increased risk for fatal and non-fatal cardiovascular and renal complications. Endovascular management of atherosclerotic RAS (ARAS) has been recently evaluated by several randomized controlled trials that failed to demonstrate benefit of stenting. Furthermore, the Cardiovascular Outcomes in Renal Atherosclerotic Lesions study did not demonstrate any benefit over the revascularization approach. In this review, we summarized the available data from retrospective, prospective and randomized trials on ARAS to provide clinicians with sufficient data in order to produce useful conclusions for everyday clinical practice. PMID:28377906

  10. Plasma viscosity increase with progression of peripheral arterial atherosclerotic disease.

    PubMed

    Poredos, P; Zizek, B

    1996-03-01

    -macroglobulin (r=0.78, P < 0.01). These results indicate that in patients with peripheral arterial disease plasma viscosity increases with the progression of the atherosclerotic process and is correlated with the clinical stages of the disease.

  11. Localisation of members of the vascular endothelial growth factor (VEGF) family and their receptors in human atherosclerotic arteries

    PubMed Central

    Belgore, F; Blann, A; Neil, D; Ahmed, A S; Lip, G Y H

    2004-01-01

    Background: Vascular endothelial growth factor (VEGF) mediates endothelial cell mitogenesis and enhances vascular permeability. The existence of single or multiple VEGF isoforms and receptors suggests that these proteins may have overlapping but distinct functions, which may be reflected in their cell expression and distribution. Methods: The localisation of VEGFs A–C and their receptors (VEGFRs 1–3, respectively) in 30 fresh human atherosclerotic arteries, 15 normal uterine arteries, and 15 saphenous veins using immunohistochemistry and western blotting. Results: Saphenous veins showed no staining for VEGF-B or VEGFR-2. Smooth muscle cells (SMCs) showed the strongest staining for VEGF-A, VEGF-B, VEGFR-1, and VEGFR-2 in all specimens. Conversely, VEGFR-3 and VEGF-C were predominately localised to the endothelial vasa vasorum in normal arteries, whereas medial SMCs showed the strongest staining in atherosclerotic arteries. Western blotting showed variations in VEGF protein localisation, with lower amounts of VEGF-B and VEGF-C in saphenous veins, compared with arterial tissue. Amounts of VEGF-C were lower than those of VEGF-A and VEGF-B in all specimens. Conclusion: This study provides direct evidence of the presence of VEGF proteins and receptors in human physiology and pathology, with variations in both the amounts of VEGF proteins expressed and their cellular distribution in normal arteries compared with atherosclerotic arteries. The presence of VEGFs A–C and their receptors in normal arterial tissue implies that VEGF functions may extend beyond endothelial cell proliferation. Reduced VEGFR-2 staining in atherosclerotic arteries may have implications for the atherosclerosis process and the development of vascular disease and its complications. PMID:14990597

  12. Preferential influx and decreased fractional loss of lipoprotein(a) in atherosclerotic compared with nonlesioned rabbit aorta.

    PubMed Central

    Nielsen, L B; Stender, S; Jauhiainen, M; Nordestgaard, B G

    1996-01-01

    The aim was to investigate the atherogenic potential of lipoprotein(a) (Lp(a)) and to further our understanding of the atherogenic process by measuring rates of transfer into the intima-inner media (i.e., intimal clearance) and rates of loss from the intima-inner media (i.e., fractional loss) of Lp(a) and LDL using cholesterol-fed rabbits with nonlesioned (n = 13) or atherosclerotic aortas (n = 12). In each rabbit, 131I-Lp(a) (or 131I-LDL) was injected intravenously 26 h before and 125I-Lp(a) (or 125I-LDL) 3 h before the aorta was removed and divided into six consecutive segments of similar size. The intimal clearance of Lp(a) and LDL was similar and markedly increased in atherosclerotic compared with nonlesioned aortas (ANOVA, effect of atherosclerosis: P < 0.0001). Fractional losses of labeled Lp(a) and labeled LDL in atherosclerotic aorta were on average 25 and 43%, respectively, of that in nonlesioned aortas (ANOVA, effect of atherosclerosis: P < 0.0001). Fractional loss of Lp(a) was 73% of that of LDL (ANOVA, effect of type of lipoprotein: P = 0.07). These data suggest that the development of atherosclerosis is associated with increased influx as well as decreased fractional loss of Lp(a) and LDL from the intima. Accordingly, Lp(a) may share with LDL the potential for causing atherosclerosis. PMID:8755669

  13. Graphics processing unit-accelerated non-rigid registration of MR images to CT images during CT-guided percutaneous liver tumor ablations

    PubMed Central

    Tokuda, Junichi; Plishker, William; Torabi, Meysam; Olubiyi, Olutayo I; Zaki, George; Tatli, Servet; Silverman, Stuart G.; Shekhar, Raj; Hata, Nobuhiko

    2015-01-01

    Rationale and Objectives Accuracy and speed are essential for the intraprocedural nonrigid MR-to-CT image registration in the assessment of tumor margins during CT-guided liver tumor ablations. While both accuracy and speed can be improved by limiting the registration to a region of interest (ROI), manual contouring of the ROI prolongs the registration process substantially. To achieve accurate and fast registration without the use of an ROI, we combined a nonrigid registration technique based on volume subdivision with hardware acceleration using a graphical processing unit (GPU). We compared the registration accuracy and processing time of GPU-accelerated volume subdivision-based nonrigid registration technique to the conventional nonrigid B-spline registration technique. Materials and Methods Fourteen image data sets of preprocedural MR and intraprocedural CT images for percutaneous CT-guided liver tumor ablations were obtained. Each set of images was registered using the GPU-accelerated volume subdivision technique and the B-spline technique. Manual contouring of ROI was used only for the B-spline technique. Registration accuracies (Dice Similarity Coefficient (DSC) and 95% Hausdorff Distance (HD)), and total processing time including contouring of ROIs and computation were compared using a paired Student’s t-test. Results Accuracy of the GPU-accelerated registrations and B-spline registrations, respectively were 88.3 ± 3.7% vs 89.3 ± 4.9% (p = 0.41) for DSC and 13.1 ± 5.2 mm vs 11.4 ± 6.3 mm (p = 0.15) for HD. Total processing time of the GPU-accelerated registration and B-spline registration techniques was 88 ± 14 s vs 557 ± 116 s (p < 0.000000002), respectively; there was no significant difference in computation time despite the difference in the complexity of the algorithms (p = 0.71). Conclusion The GPU-accelerated volume subdivision technique was as accurate as the B-spline technique and required significantly less processing time. The GPU-accelerated

  14. Computational Hemodynamic Analysis for the Diagnosis of Atherosclerotic Changes in Intracranial Aneurysms: A Proof-of-Concept Study Using 3 Cases Harboring Atherosclerotic and Nonatherosclerotic Aneurysms Simultaneously

    PubMed Central

    Endo, Hidenori; Niizuma, Kuniyasu; Endo, Toshiki; Funamoto, Kenichi; Ohta, Makoto; Tominaga, Teiji

    2016-01-01

    This was a proof-of-concept computational fluid dynamics (CFD) study designed to identify atherosclerotic changes in intracranial aneurysms. We selected 3 patients with multiple unruptured aneurysms including at least one with atherosclerotic changes and investigated whether an image-based CFD study could provide useful information for discriminating the atherosclerotic aneurysms. Patient-specific geometries were constructed from three-dimensional data obtained using rotational angiography. Transient simulations were conducted under patient-specific inlet flow rates measured by phase-contrast magnetic resonance velocimetry. In the postanalyses, we calculated time-averaged wall shear stress (WSS), oscillatory shear index, and relative residence time (RRT). The volume of blood flow entering aneurysms through the neck and the mean velocity of blood flow inside aneurysms were examined. We applied the age-of-fluid method to quantitatively assess the residence of blood inside aneurysms. Atherosclerotic changes coincided with regions exposed to disturbed blood flow, as indicated by low WSS and long RRT. Blood entered aneurysms in phase with inlet flow rates. The mean velocities of blood inside atherosclerotic aneurysms were lower than those inside nonatherosclerotic aneurysms. Blood in atherosclerotic aneurysms was older than that in nonatherosclerotic aneurysms, especially near the wall. This proof-of-concept study demonstrated that CFD analysis provided detailed information on the exchange and residence of blood that is useful for the diagnosis of atherosclerotic changes in intracranial aneurysms. PMID:27703491

  15. Effect of the drying process on the intensification of phenolic compounds recovery from grape pomace using accelerated solvent extraction.

    PubMed

    Rajha, Hiba N; Ziegler, Walter; Louka, Nicolas; Hobaika, Zeina; Vorobiev, Eugene; Boechzelt, Herbert G; Maroun, Richard G

    2014-10-15

    In light of their environmental and economic interests, food byproducts have been increasingly exploited and valorized for their richness in dietary fibers and antioxidants. Phenolic compounds are antioxidant bioactive molecules highly present in grape byproducts. Herein, the accelerated solvent extraction (ASE) of phenolic compounds from wet and dried grape pomace, at 45 °C, was conducted and the highest phenolic compounds yield (PCY) for wet (16.2 g GAE/100 g DM) and dry (7.28 g GAE/100 g DM) grape pomace extracts were obtained with 70% ethanol/water solvent at 140 °C. The PCY obtained from wet pomace was up to two times better compared to the dry byproduct and up to 15 times better compared to the same food matrices treated with conventional methods. With regard to Resveratrol, the corresponding dry pomace extract had a better free radical scavenging activity (49.12%) than the wet extract (39.8%). The drying pretreatment process seems to ameliorate the antiradical activity, especially when the extraction by ASE is performed at temperatures above 100 °C. HPLC-DAD analysis showed that the diversity of the flavonoid and the non-flavonoid compounds found in the extracts was seriously affected by the extraction temperature and the pretreatment of the raw material. This diversity seems to play a key role in the scavenging activity demonstrated by the extracts. Our results emphasize on ASE usage as a promising method for the preparation of highly concentrated and bioactive phenolic extracts that could be used in several industrial applications.

  16. Effect of the Drying Process on the Intensification of Phenolic Compounds Recovery from Grape Pomace Using Accelerated Solvent Extraction

    PubMed Central

    Rajha, Hiba N.; Ziegler, Walter; Louka, Nicolas; Hobaika, Zeina; Vorobiev, Eugene; Boechzelt, Herbert G.; Maroun, Richard G.

    2014-01-01

    In light of their environmental and economic interests, food byproducts have been increasingly exploited and valorized for their richness in dietary fibers and antioxidants. Phenolic compounds are antioxidant bioactive molecules highly present in grape byproducts. Herein, the accelerated solvent extraction (ASE) of phenolic compounds from wet and dried grape pomace, at 45 °C, was conducted and the highest phenolic compounds yield (PCY) for wet (16.2 g GAE/100 g DM) and dry (7.28 g GAE/100 g DM) grape pomace extracts were obtained with 70% ethanol/water solvent at 140 °C. The PCY obtained from wet pomace was up to two times better compared to the dry byproduct and up to 15 times better compared to the same food matrices treated with conventional methods. With regard to Resveratrol, the corresponding dry pomace extract had a better free radical scavenging activity (49.12%) than the wet extract (39.8%). The drying pretreatment process seems to ameliorate the antiradical activity, especially when the extraction by ASE is performed at temperatures above 100 °C. HPLC-DAD analysis showed that the diversity of the flavonoid and the non-flavonoid compounds found in the extracts was seriously affected by the extraction temperature and the pretreatment of the raw material. This diversity seems to play a key role in the scavenging activity demonstrated by the extracts. Our results emphasize on ASE usage as a promising method for the preparation of highly concentrated and bioactive phenolic extracts that could be used in several industrial applications. PMID:25322155

  17. Three-dimensional dynamic contrast-enhanced MRI for the accurate, extensive quantification of microvascular permeability in atherosclerotic plaques.

    PubMed

    Calcagno, Claudia; Lobatto, Mark E; Dyvorne, Hadrien; Robson, Philip M; Millon, Antoine; Senders, Max L; Lairez, Olivier; Ramachandran, Sarayu; Coolen, Bram F; Black, Alexandra; Mulder, Willem J M; Fayad, Zahi A

    2015-10-01

    Atherosclerotic plaques that cause stroke and myocardial infarction are characterized by increased microvascular permeability and inflammation. Dynamic contrast-enhanced MRI (DCE-MRI) has been proposed as a method to quantify vessel wall microvascular permeability in vivo. Until now, most DCE-MRI studies of atherosclerosis have been limited to two-dimensional (2D) multi-slice imaging. Although providing the high spatial resolution required to image the arterial vessel wall, these approaches do not allow the quantification of plaque permeability with extensive anatomical coverage, an essential feature when imaging heterogeneous diseases, such as atherosclerosis. To our knowledge, we present the first systematic evaluation of three-dimensional (3D), high-resolution, DCE-MRI for the extensive quantification of plaque permeability along an entire vascular bed, with validation in atherosclerotic rabbits. We compare two acquisitions: 3D turbo field echo (TFE) with motion-sensitized-driven equilibrium (MSDE) preparation and 3D turbo spin echo (TSE). We find 3D TFE DCE-MRI to be superior to 3D TSE DCE-MRI in terms of temporal stability metrics. Both sequences show good intra- and inter-observer reliability, and significant correlation with ex vivo permeability measurements by Evans Blue near-infrared fluorescence (NIRF). In addition, we explore the feasibility of using compressed sensing to accelerate 3D DCE-MRI of atherosclerosis, to improve its temporal resolution and therefore the accuracy of permeability quantification. Using retrospective under-sampling and reconstructions, we show that compressed sensing alone may allow the acceleration of 3D DCE-MRI by up to four-fold. We anticipate that the development of high-spatial-resolution 3D DCE-MRI with prospective compressed sensing acceleration may allow for the more accurate and extensive quantification of atherosclerotic plaque permeability along an entire vascular bed. We foresee that this approach may allow for

  18. Future accelerators (?)

    SciTech Connect

    John Womersley

    2003-08-21

    I describe the future accelerator facilities that are currently foreseen for electroweak scale physics, neutrino physics, and nuclear structure. I will explore the physics justification for these machines, and suggest how the case for future accelerators can be made.

  19. Presence of hypochlorite-modified proteins in human atherosclerotic lesions.

    PubMed Central

    Hazell, L J; Arnold, L; Flowers, D; Waeg, G; Malle, E; Stocker, R

    1996-01-01

    Oxidation of LDL may contribute to atherogenesis, though the nature of the in vivo oxidant(s) remains obscure. Myeloperoxidase, the enzyme responsible for hypochlorous acid/hypochlorite (HOCl) production in vivo, is present in active form in human atherosclerotic lesions, and HOCl aggregates and transforms LDL into a high-uptake form for macrophages in vitro. Here we demonstrate HOCl-modified proteins in human lesions using an mAb raised against HOCl-modified LDL that recognizes HOCl-oxidized proteins but does not cross-react with Cu2+-, malondialdehyde-, or 4-hydroxynonenal-modified LDL. This antibody detected significantly more material in advanced atherosclerotic lesions than normal arteries, even though azide and methionine were included during sample work-up to inhibit myeloperoxidase and to scavenge HOCl. The epitope(s) recognized was predominantly cell associated and present in monocyte/macrophages, smooth muscle, and endothelial cells. The intima and cholesterol clefts stained more heavily than the center of the thickened vessels; adventitial staining was apparent in some cases. Immunostaining was also detected in a very early lesion from an accident victim, beside healthy areas that were unreactive. LDL oxidized by HOCl in vitro, but not native LDL, effectively competed with the epitopes in lesions for antibody binding. Density centrifugation of plaque homogenates and Western blot analysis showed that, in the apo B-containing lipoprotein fraction, the mAb recognized protein(s) of molecular mass greater than apo B, similar to those produced during oxidation of LDL with HOCl in vitro. Three major proteins were recognized by the anti-HOCl-modified protein antibody but not by an anti-apo B antibody in the apo B-free fraction. Together, these results demonstrate HOCl-oxidized proteins in human atherosclerotic lesions, implicating this oxidant in LDL modification in vivo. PMID:8617887

  20. Identification of Atherosclerotic Plaques in Carotid Artery by Fluorescence Spectroscopy

    NASA Astrophysics Data System (ADS)

    Rocha, Rick; Villaverde, Antonio Balbin; Silveira, Landulfo; Costa, Maricília Silva; Alves, Leandro Procópio; Pasqualucci, Carlos Augusto; Brugnera, Aldo

    2008-04-01

    The aim of this work was to identify the presence of atherosclerotic plaques in carotid artery using the Fluorescence Spectroscopy. The most important pathogeny in the cardiovascular disorders is the atherosclerosis, which may affect even younger individuals. With approximately 1.2 million heart attacks and 750,000 strokes afflicting an aging American population each year, cardiovascular disease remains the number one cause of death. Carotid artery samples were obtained from the Autopsy Service at the University of São Paulo (São Paulo, SP, Brazil) taken from cadavers. After a histopathological analysis the 60 carotid artery samples were divided into two groups: normal (26) and atherosclerotic plaques (34). Samples were irradiated with the wavelength of 488 nm from an Argon laser. A 600 μm core optical fiber, coupled to the Argon laser, was used for excitation of the sample, whereas another 600 optical fiber, coupled to the spectrograph entrance slit, was used for collecting the fluorescence from the sample. Measurements were taken at different points on each sample and then averaged. Fluorescence spectra showed a single broad line centered at 549 nm. The fluorescence intensity for each sample was calculated by subtracting the intensity at the peak (550 nm) and at the bottom (510 nm) and then data were statistically analyzed, looking for differences between both groups of samples. ANOVA statistical test showed a significant difference (p<0,05) between both types of tissues, with regard to the fluorescence peak intensities. Our results indicate that this technique could be used to detect the presence of the atherosclerotic in carotid tissue.

  1. Apolipoprotein B-containing lipoproteins and atherosclerotic cardiovascular disease

    PubMed Central

    Shapiro, Michael D.; Fazio, Sergio

    2017-01-01

    Cholesterol-rich, apolipoprotein B (apoB)-containing lipoproteins are now widely accepted as the most important causal agents of atherosclerotic cardiovascular disease. Multiple unequivocal and orthogonal lines of evidence all converge on low-density lipoprotein and related particles as being the principal actors in the genesis of atherosclerosis. Here, we review the fundamental role of atherogenic apoB-containing lipoproteins in cardiovascular disease and several other humoral and parietal factors that are required to initiate and maintain arterial degeneration. The biology of foam cells and their interactions with high-density lipoproteins, including cholesterol efflux, are also briefly reviewed. PMID:28299190

  2. Management of hypertriglyceridemia for prevention of atherosclerotic cardiovascular disease.

    PubMed

    Brinton, Eliot A

    2015-05-01

    Mendelian randomization data strongly suggest that hypertriglyceridemia (HTG) causes atherosclerotic cardiovascular disease (ASCVD), and so triglyceride (TG) level-lowering treatment in HTG is now more strongly recommended to address the residual ASCVD risk than has been the case in (generally earlier) published guidelines. Fibrates are the best-established agents for TG level lowering and are generally used as first-line treatment of TG levels greater than 500 mg/dL. Statins are the best-established agents for ASCVD prevention, and so are usually used as first-line treatment of TG levels less than 500 mg/dL.

  3. Colocalization of 15-lipoxygenase mRNA and protein with epitopes of oxidized low density lipoprotein in macrophage-rich areas of atherosclerotic lesions.

    PubMed Central

    Ylä-Herttuala, S; Rosenfeld, M E; Parthasarathy, S; Glass, C K; Sigal, E; Witztum, J L; Steinberg, D

    1990-01-01

    Oxidation of low density lipoprotein (LDL) enhances its atherogenicity, and inhibition of such oxidation decreases the rate of progression of atherosclerotic lesions. The mechanism of LDL oxidation in vivo remains uncertain, but in vitro studies have suggested that cellular lipoxygenases may play a role by initiating lipid peroxidation in LDL. In situ hybridization studies using a 15-lipoxygenase riboprobe and immunostaining using antibodies against 15-lipoxygenase showed strongly positive reactivity largely confined to macrophage-rich areas of atherosclerotic lesions. Polymerase chain reaction with 15-lipoxygenase-specific oligonucleotides and restriction enzyme digestions of the amplified fragment were used to confirm the presence of 15-lipoxygenase message in the reverse-transcribed lesion mRNA. Immunostaining with antibodies reactive with oxidized LDL (but not with native LDL) indicated that the lipoxygenase colocalizes with epitopes of oxidized LDL, compatible with a role for macrophage lipoxygenase in the oxidation of LDL in vivo. Since oxidized LDL is chemotactic for blood monocytes, early lesions might progress at a markedly accelerated rate because of further recruitment of more monocytes which, in turn, would increase further the rate of oxidation of LDL. These data suggest that therapy targeted to block macrophage lipoxygenase activity might decrease the rate of development of atherosclerotic lesions. Images PMID:1698286

  4. Additive electroplating technology as a post-CMOS process for the production of MEMS acceleration-threshold switches for transportation applications

    NASA Astrophysics Data System (ADS)

    Michaelis, Sven; Timme, Hans-Jörg; Wycisk, Michael; Binder, Josef

    2000-06-01

    This paper presents an acceleration-threshold sensor fabricated with an electroplating technology which can be integrated on top of a pre-processed CMOS signal processing circuit. The device can be manufactured using a standard low-cost CMOS production line and then adding the mechanical sensor elements via a specialized back-end process. This makes the system especially interesting for automotive applications, such as airbag safety systems or transportation shock monitoring systems, where smaller size, improved functionality, high reliability and low costs are important.

  5. High Gradient Accelerator Research

    SciTech Connect

    Temkin, Richard

    2016-07-12

    The goal of the MIT program of research on high gradient acceleration is the development of advanced acceleration concepts that lead to a practical and affordable next generation linear collider at the TeV energy level. Other applications, which are more near-term, include accelerators for materials processing; medicine; defense; mining; security; and inspection. The specific goals of the MIT program are: • Pioneering theoretical research on advanced structures for high gradient acceleration, including photonic structures and metamaterial structures; evaluation of the wakefields in these advanced structures • Experimental research to demonstrate the properties of advanced structures both in low-power microwave cold test and high-power, high-gradient test at megawatt power levels • Experimental research on microwave breakdown at high gradient including studies of breakdown phenomena induced by RF electric fields and RF magnetic fields; development of new diagnostics of the breakdown process • Theoretical research on the physics and engineering features of RF vacuum breakdown • Maintaining and improving the Haimson / MIT 17 GHz accelerator, the highest frequency operational accelerator in the world, a unique facility for accelerator research • Providing the Haimson / MIT 17 GHz accelerator facility as a facility for outside users • Active participation in the US DOE program of High Gradient Collaboration, including joint work with SLAC and with Los Alamos National Laboratory; participation of MIT students in research at the national laboratories • Training the next generation of Ph. D. students in the field of accelerator physics.

  6. Decolorization of anthraquinone dye intermediate and its accelerating effect on reduction of azo acid dyes by Sphingomonas xenophaga in anaerobic-aerobic process.

    PubMed

    Lu, Hong; Zhou, Jiti; Wang, Jing; Ai, Haixin; Zheng, Chunli; Yang, Yusuo

    2008-09-01

    Decolorization of 1-aminoanthraquinone-2-sulfonic acid (ASA-2) and its accelerating effect on the reduction of azo acid dyes by Sphingomonas xenophaga QYY were investigated. The study showed that ASA-2 could be efficiently decolorized by strain QYY under aerobic conditions according to the analysis of total organic carbon removal and UV-VIS spectra changes. Moreover, strain QYY was able to reduce azo acid dyes under anaerobic conditions. The effects of various operating conditions such as carbon sources, temperature, and pH on the reduction rate were studied. It was demonstrated that ASA-2 used as a redox mediator could accelerate the reduction process. Consequently the reduction of azo acid dyes mediated by ASA-2 and the decolorization of ASA-2 with strain QYY could be achieved in an anaerobic-aerobic process.

  7. Diagnosis and management of atherosclerotic cardiovascular disease in chronic kidney disease: a review.

    PubMed

    Mathew, Roy O; Bangalore, Sripal; Lavelle, Michael P; Pellikka, Patricia A; Sidhu, Mandeep S; Boden, William E; Asif, Arif

    2016-12-28

    Patients with chronic kidney disease (CKD) have a high prevalence of atherosclerotic cardiovascular disease, likely reflecting the presence of traditional risk factors. A greater distinguishing feature of atherosclerotic cardiovascular disease in CKD is the severity of the disease, which is reflective of an increase in inflammatory mediators and vascular calcification secondary to hyperparathyroidism of renal origin that are unique to patients with CKD. Additional components of atherosclerotic cardiovascular disease that are prominent in patients with CKD include microvascular disease and myocardial fibrosis. Therapeutic interventions that minimize cardiovascular events related to atherosclerotic cardiovascular disease in patients with CKD, as determined by well-designed clinical trials, are limited to statins. Data are lacking regarding other available therapeutic measures primarily due to exclusion of patients with CKD from major trials studying cardiovascular disease. Data from well-designed randomized controlled trials are needed to guide clinicians who care for this high-risk population in the management of atherosclerotic cardiovascular disease to improve clinical outcomes.

  8. Numerical observer for atherosclerotic plaque classification in spectral computed tomography.

    PubMed

    Lorsakul, Auranuch; Fakhri, Georges El; Worstell, William; Ouyang, Jinsong; Rakvongthai, Yothin; Laine, Andrew F; Li, Quanzheng

    2016-07-01

    Spectral computed tomography (SCT) generates better image quality than conventional computed tomography (CT). It has overcome several limitations for imaging atherosclerotic plaque. However, the literature evaluating the performance of SCT based on objective image assessment is very limited for the task of discriminating plaques. We developed a numerical-observer method and used it to assess performance on discrimination vulnerable-plaque features and compared the performance among multienergy CT (MECT), dual-energy CT (DECT), and conventional CT methods. Our numerical observer was designed to incorporate all spectral information and comprised two-processing stages. First, each energy-window domain was preprocessed by a set of localized channelized Hotelling observers (CHO). In this step, the spectral image in each energy bin was decorrelated using localized prewhitening and matched filtering with a set of Laguerre-Gaussian channel functions. Second, the series of the intermediate scores computed from all the CHOs were integrated by a Hotelling observer with an additional prewhitening and matched filter. The overall signal-to-noise ratio (SNR) and the area under the receiver operating characteristic curve (AUC) were obtained, yielding an overall discrimination performance metric. The performance of our new observer was evaluated for the particular binary classification task of differentiating between alternative plaque characterizations in carotid arteries. A clinically realistic model of signal variability was also included in our simulation of the discrimination tasks. The inclusion of signal variation is a key to applying the proposed observer method to spectral CT data. Hence, the task-based approaches based on the signal-known-exactly/background-known-exactly (SKE/BKE) framework and the clinical-relevant signal-known-statistically/background-known-exactly (SKS/BKE) framework were applied for analytical computation of figures of merit (FOM). Simulated data of a

  9. Complications during renal artery stent placement for atherosclerotic ostial stenosis

    SciTech Connect

    Beek, Frederik J. A.; Kaatee, Robert; Beutler, Jaap J.; Ven, Peter J. van der; Mali, Willem P. T. M.

    1997-05-15

    Purpose. To describe short-term complications during stent placement for atherosclerotic renal artery ostial stenosis. Methods. Sixty-one arteries in 50 patients were treated with Palmaz stents. Nineteen patients had a single functioning kidney, 23 had a bilateral stenosis, which was stented bilaterally in 11, and 8 had a unilateral stenosis. The complications were grouped as those related to the catheterization procedure, those related to stent placement, and those possibly related to either category. The complications were divided into those with severe clinical significance (SCS), those with minor clinical significance (MCS), and radiological-technical complications (RTC). The stent placement procedures were ordered chronologically according to examination date and the complications were tabulated per group of 10 patients. Results. Five (10%) SCS, 5 (10%) MCS, and 8 (16%) RTC occurred in 50 patients. The catheterization procedure led to 2 SCS, 3 MCS, and 1 RTC. Stent placement gave rise to 7 RTC. Three SCS and 2 MCS could have been related to either catheterization or stent placement. More SCS occurred in the first group of 10 patients than in the following groups. Conclusion. Renal artery stent placement for atherosclerotic ostial stenosis has a considerable complication rate and a learning curve is present. The complications related to the actual stent placement were without clinical consequences.

  10. Inadequate dietary magnesium intake increases atherosclerotic plaque development in rabbits

    PubMed Central

    King, Jennifer L.; Miller, Rita J.; Blue, James P.; O'Brien, William D.; Erdman, John W.

    2012-01-01

    Epidemiological studies have shown dietary magnesium (Mg) intake and serum Mg levels to be inversely correlated with the development of atherosclerosis. We hypothesized that low levels of Mg would promote atherosclerotic plaque development in rabbits. New Zealand white rabbits (4 months old, n = 22) were fed an atherogenic diet containing 0.12% (−Mg), 0.27% (control), or 0.43% (+Mg) Mg for 8 weeks. Blood samples were obtained at baseline, 2, 4, 6, and 8 weeks and were assayed for total cholesterol, high-density lipoprotein (HDL), non-HDL, triglycerides (TG), C-reactive protein, serum Mg, and erythrocyte Mg. Aortas from −Mg had significantly more plaque, with an intima thickness 42% greater than control and 36% greater than +Mg. Serum cholesterol levels rose over time, and at 8 weeks, −Mg had the highest and +Mg the lowest total and non-HDL cholesterol and TG levels, although these results did not reach significance. Over time, serum Mg levels increased, and erythrocyte Mg levels decreased. C-reactive protein significantly increased in all groups at 4 and 6 weeks but returned to baseline levels by 8 weeks. This study supports the hypothesis that inadequate intake of Mg results in an increase in atherosclerotic plaque development in rabbits. PMID:19555816

  11. Imaging of the Fibrous Cap in Atherosclerotic Carotid Plaque

    SciTech Connect

    Saba, Luca; Potters, Fons; Lugt, Aad van der; Mallarini, Giorgio

    2010-08-15

    In the last two decades, a substantial number of articles have been published to provide diagnostic solutions for patients with carotid atherosclerotic disease. These articles have resulted in a shift of opinion regarding the identification of stroke risk in patients with carotid atherosclerotic disease. In the recent past, the degree of carotid artery stenosis was the sole determinant for performing carotid intervention (carotid endarterectomy or carotid stenting) in these patients. We now know that the degree of stenosis is only one marker for future cerebrovascular events. If one wants to determine the risk of these events more accurately, other parameters must be taken into account; among these parameters are plaque composition, presence and state of the fibrous cap (FC), intraplaque haemorrhage, plaque ulceration, and plaque location. In particular, the FC is an important structure for the stability of the plaque, and its rupture is highly associated with a recent history of transient ischaemic attack or stroke. The subject of this review is imaging of the FC.

  12. Noninvasive imaging of focal atherosclerotic lesions using fluorescence molecular tomography

    NASA Astrophysics Data System (ADS)

    Maji, Dolonchampa; Solomon, Metasebya; Nguyen, Annie; Pierce, Richard A.; Woodard, Pamela K.; Akers, Walter J.; Achilefu, Samuel; Culver, Joseph P.; Abendschein, Dana R.; Shokeen, Monica

    2014-11-01

    Insights into the etiology of stroke and myocardial infarction suggest that rupture of unstable atherosclerotic plaque is the precipitating event. Clinicians lack tools to detect lesion instability early enough to intervene, and are often left to manage patients empirically, or worse, after plaque rupture. Noninvasive imaging of the molecular events signaling prerupture plaque progression has the potential to reduce the morbidity and mortality associated with myocardial infarction and stroke by allowing early intervention. Here, we demonstrate proof-of-principle in vivo molecular imaging of C-type natriuretic peptide receptor in focal atherosclerotic lesions in the femoral arteries of New Zealand white rabbits using a custom built fiber-based, fluorescence molecular tomography (FMT) system. Longitudinal imaging showed changes in the fluorescence signal intensity as the plaque progressed in the air-desiccated vessel compared to the uninjured vessel, which was validated by ex vivo tissue studies. In summary, we demonstrate the potential of FMT for noninvasive detection of molecular events leading to unstable lesions heralding plaque rupture.

  13. Functional Heterogeneity of Nadph Oxidases in Atherosclerotic and Aneurysmal Diseases

    PubMed Central

    Kigawa, Yasuyoshi; Lei, Xiao-Feng; Kim-Kaneyama, Joo-ri; Miyazaki, Akira

    2017-01-01

    NADPH oxidases (NOX) are enzymes that catalyze the production of reactive oxygen species (ROS). Four species of NOX catalytic homologs (NOX1, NOX2, NOX4, and NOX5) are reportedly expressed in vascular tissues. The pro-atherogenic roles of NOX1, NOX2, and their organizer protein p47phox were manifested, and it was noted that the hydrogen peroxide-generating enzyme NOX4 possesses atheroprotective effects. Loss of NOX1 or p47phox appears to ameliorate murine aortic dissection and subsequent aneurysmal diseases; in contrast, the ablation of NOX2 exacerbates the aneurysmal diseases. It is possible that the loss of NOX2 activates inflammatory cascades in macrophages in the lesions. Roles of NOX5 in vascular functions are currently undetermined, owing to the absence of this enzyme in rodents and the limitation of the experimental procedure. Thus, it is possible that the NOX family of enzymes exhibits heterogeneity in the atherosclerotic diseases. In this aspect, subtype-selective NOX inhibitor may be promising when NOX systems serve as a molecular target for atherosclerotic and aneurysmal diseases. PMID:27476665

  14. Indocyanine green enables near-infrared fluorescence imaging of lipid-rich, inflamed atherosclerotic plaques.

    PubMed

    Vinegoni, Claudio; Botnaru, Ion; Aikawa, Elena; Calfon, Marcella A; Iwamoto, Yoshiko; Folco, Eduardo J; Ntziachristos, Vasilis; Weissleder, Ralph; Libby, Peter; Jaffer, Farouc A

    2011-05-25

    New high-resolution molecular and structural imaging strategies are needed to visualize high-risk plaques that are likely to cause acute myocardial infarction, because current diagnostic methods do not reliably identify at-risk subjects. Although molecular imaging agents are available for low-resolution detection of atherosclerosis in large arteries, a lack of imaging agents coupled to high-resolution modalities has limited molecular imaging of atherosclerosis in the smaller coronary arteries. Here, we have demonstrated that indocyanine green (ICG), a Food and Drug Administration-approved near-infrared fluorescence (NIRF)-emitting compound, targets atheromas within 20 min of injection and provides sufficient signal enhancement for in vivo detection of lipid-rich, inflamed, coronary-sized plaques in atherosclerotic rabbits. In vivo NIRF sensing was achieved with an intravascular wire in the aorta, a vessel of comparable caliber to human coronary arteries. Ex vivo fluorescence reflectance imaging showed high plaque target-to-background ratios in atheroma-bearing rabbits injected with ICG compared to atheroma-bearing rabbits injected with saline. In vitro studies using human macrophages established that ICG preferentially targets lipid-loaded macrophages. In an early clinical study of human atheroma specimens from four patients, we found that ICG colocalized with plaque macrophages and lipids. The atheroma-targeting capability of ICG has the potential to accelerate the clinical development of NIRF molecular imaging of high-risk plaques in humans.

  15. Symptomatic Atherosclerotic Disease and Decreased Risk of Cancer-Specific Mortality

    PubMed Central

    Benito-León, Julián; de la Aleja, Jesús González; Martínez-Salio, Antonio; Louis, Elan D.; Lichtman, Judith H.; Bermejo-Pareja, Félix

    2015-01-01

    Abstract The few studies that have assessed the association between symptomatic atherosclerotic disease and risk of cancer have had conflicting results. In addition, these studies ascertained participants either from treatment settings (ie, service-based studies) or by using a records linkage system (ie, medical records of patients evaluated at clinics or hospitals) and, therefore, were prone to selection bias. Our purpose was to estimate the risk of cancer mortality in a large population-based sample of elderly people, comparing participants with symptomatic atherosclerotic disease (atherosclerotic stroke and coronary disease) to their counterparts without symptomatic atherosclerotic disease (ie, controls) in the same population. In this population-based, prospective study (Neurological Disorders of Central Spain, NEDICES), 5262 elderly community-dwelling participants with and without symptomatic atherosclerotic disease were identified and followed for a median of 12.1 years, after which the death certificates of those who died were reviewed. A total of 2701 (53.3%) of 5262 participants died, including 314 (68.6%) of 458 participants with symptomatic atherosclerotic disease and 2387 (49.7%) of 4804 controls. Cancer mortality was reported significantly less often in those with symptomatic atherosclerotic disease (15.6%) than in controls (25.6%) (P < 0.001). In an unadjusted Cox model, risk of cancer-specific mortality was decreased in participants with symptomatic atherosclerotic disease (HR = 0.74, 95% confidence interval [CI], 0.55−0.98, P = 0.04) vs. those without symptomatic atherosclerotic disease (reference group). In an adjusted Cox model, HR = 0.58; 95% CI, 0.38−0.89; P = 0.01. This population-based, prospective study suggests that there is an inverse association between symptomatic atherosclerotic disease and risk of cancer mortality. PMID:26266364

  16. Is Cadmium Exposure Associated with the Burden, Vulnerability and Rupture of Human Atherosclerotic Plaques?

    PubMed Central

    Sallsten, Gerd; Lundh, Thomas; Barregard, Lars

    2015-01-01

    The general population is exposed to cadmium from food and smoking. Cadmium is a widely spread toxic pollutant that seems to be associated with cardiovascular diseases, although little is known if it contributes to the occurrence of atherosclerotic plaques and the process whereby plaques become vulnerable and are prone to rupture. We tested the hypotheses that cadmium exposure is associated not only with an increased subclinical burden of atherosclerotic plaques in different vascular territories and early signs of plaque vulnerability, but also with cadmium content and plaque-rupture in the clinical phase of the disease. Ultrasound technique was used to measure plaque prevalence and echogenicity in the carotid and femoral arteries in a population sample of women (n = 599) in whom blood cadmium was measured. In addition cadmium was measured in snap-frozen endarterectomies and whole blood obtained from patients who were referred to surgery because of symptomatic carotid plaques (n = 37). Sixteen endarterectomies were divided into three parts corresponding to different flow conditions and plaque vulnerability. In the population sample blood cadmium was associated with the number of vascular territories with plaques (p = 0.003 after adjustment for potential confounders). The cadmium concentrations in symptomatic plaques were 50-fold higher in plaque tissue than in blood. Cadmium levels in blood and plaque correlated, also after adjustment for smoking and other cardiovascular risk factors (p<0.001). Compared with the other parts of the plaque, the cadmium content was double as high in the part where plaque rupture usually occurs. In conclusion, the results show that cadmium exposure is associated with the burden of subclinical atherosclerosis in middle-aged women with different degrees of glucose tolerance, and that the content of cadmium in symptomatic plaques in patients is related to that in blood, but much higher, and preferentially located in the part of plaque

  17. Recombinant growth factor mixtures induce cell cycle progression and the upregulation of type I collagen in human skin fibroblasts, resulting in the acceleration of wound healing processes.

    PubMed

    Lee, Do Hyun; Choi, Kyung-Ha; Cho, Jae-We; Kim, So Young; Kwon, Tae Rin; Choi, Sun Young; Choi, Yoo Mi; Lee, Jay; Yoon, Ho Sang; Kim, Beom Joon

    2014-05-01

    Application of growth factor mixtures has been used for wound healing and anti-wrinkles agents. The aim of this study was to evaluate the effect of recombinant growth factor mixtures (RGFM) on the expression of cell cycle regulatory proteins, type I collagen, and wound healing processes of acute animal wound models. The results showed that RGFM induced increased rates of cell proliferation and cell migration of human skin fibroblasts (HSF). In addition, expression of cyclin D1, cyclin E, cyclin-dependent kinase (Cdk)4, and Cdk2 proteins was markedly increased with a growth factor mixtures treatment in fibroblasts. Expression of type I collagen was also increased in growth factor mixtures-treated HSF. Moreover, growth factor mixtures-induced the upregulation of type I collagen was associated with the activation of Smad2/3. In the animal model, RGFM-treated mice showed accelerated wound closure, with the closure rate increasing as early as on day 7, as well as re-epithelization and reduced inflammatory cell infiltration than phosphate-buffered saline (PBS)-treated mice. In conclusion, the results indicated that RGFM has the potential to accelerate wound healing through the upregulation of type I collagen, which is partly mediated by activation of Smad2/3-dependent signaling pathway as well as cell cycle progression in HSF. The topical application of growth factor mixtures to acute and chronic skin wound may accelerate the epithelization process through these molecular mechanisms.

  18. On the retention of high-energy protons and nuclei with charges Z or equal to 2 in large solar flares after the process of their acceleration

    NASA Technical Reports Server (NTRS)

    Volodichev, N. N.; Kuzhevsky, B. M.; Nechaev, O. Y.; Savenko, I. A.

    1985-01-01

    Data which suggest that the protons with energies of up to several GeV should be retained on the Sun after the process of their acceleration are presented. The protons are on the average retained for 15 min, irrespectively of the solar flare heliolatitude and of the accelerated particle energy ranging from 100 MeV to several GeV. It is suggested that the particles are retained in a magnetic trap formed in a solar active region. No Z or = 2 nuclei of solar origin during large solar flares. The absence of the 500 MeV/nucleon nuclei with Z or = 2 may be due to their retention in the magnetic trap which also retains the high-energy protons. During the trapping time the approx. 500 MeV/nucleon nuclei with Z or = 2 may escape due to nuclear interactions and ionization loss.

  19. Local Effects of Human PCSK9 on the Atherosclerotic Lesion

    PubMed Central

    Giunzioni, Ilaria; Tavori, Hagai; Covarrubias, Roman; Major, Amy S.; Ding, Lei; Zhang, Youmin; DeVay, Rachel M.; Hong, Liang; Fan, Daping; Predazzi, Irene M.; Rashid, Shirya; Linton, MacRae F.; Fazio, Sergio

    2015-01-01

    Proprotein Convertase Subtilisin/Kexin type 9 (PCSK9) promotes atherosclerosis by increasing low-density lipoprotein (LDL) cholesterol levels through degradation of hepatic LDL receptors (LDLR). Studies have described the systemic effects of PCSK9 on atherosclerosis, but whether PCSK9 has local and direct effects on the plaque in unknown. To study the local effect of human PCSK9 (hPCSK9) on atherosclerotic lesion composition independently of changes in serum cholesterol levels we generated chimeric mice expressing hPCSK9 exclusively from macrophages using marrow from hPCSK9 transgenic (hPCSK9tg) mice transplanted into apoE−/− and LDLR−/− mice, which were then placed on a high fat diet for 8 wk. We further characterized the effect of hPCSK9 expression on the inflammatory responses in the spleen and by mouse peritoneal macrophages (MPM) in vitro. We found that MPM from transgenic mice express both murine (m) Pcsk9 and hPCSK9 and that the latter reduces macrophage LDLR and LRP1 surface levels. hPCSK9 was detected in serum of mice transplanted with hPCSK9tg marrow, but did not influence lipid levels or atherosclerotic lesion size. However, marrow-derived PCSK9 progressively accumulated in lesions of apoE−/− recipient mice while increasing the infiltration of Ly6Chi inflammatory monocytes by 32% compared with controls. Expression of hPCSK9 also increased CD11b and Ly6Chi positive cell numbers in spleens of apoE−/− mice. In vitro, expression of hPCSK9 in LPS-stimulated macrophages increased mRNA levels of the pro-inflammatory markers Tnf and Il1b (40% and 45%, respectively) and suppressed those of the anti-inflammatory markers Il10 and Arg1 (30% and 44%, respectively). All PCSK9 effects were LDLR-dependent as PCSK9 protein was not detected in lesions of LDLR−/− recipient mice and did not affect macrophage or splenocyte inflammation. In conclusion, PCSK9 directly increases atherosclerotic lesion inflammation in an LDLR-dependent but cholesterol

  20. Local effects of human PCSK9 on the atherosclerotic lesion.

    PubMed

    Giunzioni, Ilaria; Tavori, Hagai; Covarrubias, Roman; Major, Amy S; Ding, Lei; Zhang, Youmin; DeVay, Rachel M; Hong, Liang; Fan, Daping; Predazzi, Irene M; Rashid, Shirya; Linton, MacRae F; Fazio, Sergio

    2016-01-01

    Proprotein convertase subtilisin/kexin type 9 (PCSK9) promotes atherosclerosis by increasing low-density lipoprotein (LDL) cholesterol levels through degradation of hepatic LDL receptor (LDLR). Studies have described the systemic effects of PCSK9 on atherosclerosis, but whether PCSK9 has local and direct effects on the plaque is unknown. To study the local effect of human PCSK9 (hPCSK9) on atherosclerotic lesion composition, independently of changes in serum cholesterol levels, we generated chimeric mice expressing hPCSK9 exclusively from macrophages, using marrow from hPCSK9 transgenic (hPCSK9tg) mice transplanted into apoE(-/-) and LDLR(-/-) mice, which were then placed on a high-fat diet (HFD) for 8 weeks. We further characterized the effect of hPCSK9 expression on the inflammatory responses in the spleen and by mouse peritoneal macrophages (MPM) in vitro. We found that MPMs from transgenic mice express both murine (m) Pcsk9 and hPCSK9 and that the latter reduces macrophage LDLR and LRP1 surface levels. We detected hPCSK9 in the serum of mice transplanted with hPCSK9tg marrow, but did not influence lipid levels or atherosclerotic lesion size. However, marrow-derived PCSK9 progressively accumulated in lesions of apoE(-/-) recipient mice, while increasing the infiltration of Ly6C(hi) inflammatory monocytes by 32% compared with controls. Expression of hPCSK9 also increased CD11b- and Ly6C(hi) -positive cell numbers in spleens of apoE(-/-) mice. In vitro, expression of hPCSK9 in LPS-stimulated macrophages increased mRNA levels of the pro-inflammatory markers Tnf and Il1b (40% and 45%, respectively) and suppressed those of the anti-inflammatory markers Il10 and Arg1 (30% and 44%, respectively). All PCSK9 effects were LDLR-dependent, as PCSK9 protein was not detected in lesions of LDLR(-/-) recipient mice and did not affect macrophage or splenocyte inflammation. In conclusion, PCSK9 directly increases atherosclerotic lesion inflammation in an LDLR-dependent but

  1. Anti-Atherosclerotic Effects of a Phytoestrogen-Rich Herbal Preparation in Postmenopausal Women.

    PubMed

    Myasoedova, Veronika A; Kirichenko, Tatyana V; Melnichenko, Alexandra A; Orekhova, Varvara A; Ravani, Alessio; Poggio, Paolo; Sobenin, Igor A; Bobryshev, Yuri V; Orekhov, Alexander N

    2016-08-11

    The risk of cardiovascular disease and atherosclerosis progression is significantly increased after menopause, probably due to the decrease of estrogen levels. The use of hormone replacement therapy (HRT) for prevention of cardiovascular disease in older postmenopausal failed to meet expectations. Phytoestrogens may induce some improvements in climacteric symptoms, but their effect on the progression of atherosclerosis remains unclear. The reduction of cholesterol accumulation at the cellular level should lead to inhibition of the atherosclerotic process in the arterial wall. The inhibition of intracellular lipid deposition with isoflavonoids was suggested as the effective way for the prevention of plaque formation in the arterial wall. The aim of this double-blind, placebo-controlled clinical study was to investigate the effect of an isoflavonoid-rich herbal preparation on atherosclerosis progression in postmenopausal women free of overt cardiovascular disease. One hundred fifty-seven healthy postmenopausal women (age 65 ± 6) were randomized to a 500 mg isoflavonoid-rich herbal preparation containing tannins from grape seeds, green tea leaves, hop cone powder, and garlic powder, or placebo. Conventional cardiovascular risk factors and intima-media thickness of common carotid arteries (cIMT) were evaluated at the baseline and after 12 months of treatment. After 12-months follow-up, total cholesterol decreased by 6.3% in isoflavonoid-rich herbal preparation recipients (p = 0.011) and by 5.2% in placebo recipients (p = 0.020); low density lipoprotein (LDL) cholesterol decreased by 7.6% in isoflavonoid-rich herbal preparation recipients (p = 0.040) and by 5.2% in placebo recipients (non-significant, NS); high density lipoprotein (HDL) cholesterol decreased by 3.4% in isoflavonoid-rich herbal preparation recipients (NS) and by 4.5% in placebo recipients (p = 0.038); triglycerides decreased by 6.0% in isoflavonoid-rich herbal preparation recipients (NS) and by 7.1% in

  2. Anti-Atherosclerotic Effects of a Phytoestrogen-Rich Herbal Preparation in Postmenopausal Women

    PubMed Central

    Myasoedova, Veronika A.; Kirichenko, Tatyana V.; Melnichenko, Alexandra A.; Orekhova, Varvara A.; Ravani, Alessio; Poggio, Paolo; Sobenin, Igor A.; Bobryshev, Yuri V.; Orekhov, Alexander N.

    2016-01-01

    The risk of cardiovascular disease and atherosclerosis progression is significantly increased after menopause, probably due to the decrease of estrogen levels. The use of hormone replacement therapy (HRT) for prevention of cardiovascular disease in older postmenopausal failed to meet expectations. Phytoestrogens may induce some improvements in climacteric symptoms, but their effect on the progression of atherosclerosis remains unclear. The reduction of cholesterol accumulation at the cellular level should lead to inhibition of the atherosclerotic process in the arterial wall. The inhibition of intracellular lipid deposition with isoflavonoids was suggested as the effective way for the prevention of plaque formation in the arterial wall. The aim of this double-blind, placebo-controlled clinical study was to investigate the effect of an isoflavonoid-rich herbal preparation on atherosclerosis progression in postmenopausal women free of overt cardiovascular disease. One hundred fifty-seven healthy postmenopausal women (age 65 ± 6) were randomized to a 500 mg isoflavonoid-rich herbal preparation containing tannins from grape seeds, green tea leaves, hop cone powder, and garlic powder, or placebo. Conventional cardiovascular risk factors and intima-media thickness of common carotid arteries (cIMT) were evaluated at the baseline and after 12 months of treatment. After 12-months follow-up, total cholesterol decreased by 6.3% in isoflavonoid-rich herbal preparation recipients (p = 0.011) and by 5.2% in placebo recipients (p = 0.020); low density lipoprotein (LDL) cholesterol decreased by 7.6% in isoflavonoid-rich herbal preparation recipients (p = 0.040) and by 5.2% in placebo recipients (non-significant, NS); high density lipoprotein (HDL) cholesterol decreased by 3.4% in isoflavonoid-rich herbal preparation recipients (NS) and by 4.5% in placebo recipients (p = 0.038); triglycerides decreased by 6.0% in isoflavonoid-rich herbal preparation recipients (NS) and by 7.1% in

  3. Dietary Carnosine Prevents Early Atherosclerotic Lesion Formation in ApoE-null Mice

    PubMed Central

    Barski, Oleg A.; Xie, Zhengzhi; Baba, Shahid P.; Sithu, Srinivas D.; Agarwal, Abhinav; Cai, Jian; Bhatnagar, Aruni; Srivastava, Sanjay

    2013-01-01

    Objective Atherosclerotic lesions are associated with the accumulation of reactive aldehydes derived from oxidized lipids. Although inhibition of aldehyde metabolism has been shown to exacerbate atherosclerosis and enhance the accumulation of aldehyde-modified proteins in atherosclerotic plaques, no therapeutic interventions have been devised to prevent aldehyde accumulation in atherosclerotic lesions. Approach and Results We examined the efficacy of carnosine, a naturally occurring β-alanyl-histidine dipeptide in preventing aldehyde toxicity and atherogenesis in apoE-null mice. In vitro, carnosine reacted rapidly with lipid peroxidation-derived unsaturated aldehydes. Gas chromatography mass-spectrometry analysis showed that carnosine inhibits the formation of free aldehydes - HNE and malonaldialdehyde in Cu2+-oxidized LDL. Preloading bone marrow-derived macrophages with cell-permeable carnosine analogs reduced HNE-induced apoptosis. Oral supplementation with octyl-D-carnosine decreased atherosclerotic lesion formation in aortic valves of apoE-null mice and attenuated the accumulation of protein-acrolein, protein-HHE and protein-HNE adducts in atherosclerotic lesions, while urinary excretion of aldehydes as carnosine conjugates was increased. Conclusions The results of this study suggest that carnosine inhibits atherogenesis by facilitating aldehyde removal from atherosclerotic lesions. Endogenous levels of carnosine may be important determinants of atherosclerotic lesion formation and treatment with carnosine or related peptides could be a useful therapy for the prevention or the treatment of atherosclerosis. PMID:23559625

  4. Evaluation and percutaneous management of atherosclerotic peripheral vascular disease

    SciTech Connect

    Widlus, D.M.; Osterman, F.A. Jr. )

    1989-06-02

    Atherosclerotic peripheral vascular disease (PVD) of the lower extremities deprives a person of the ability to exercise to their satisfaction, later of the ability to perform the activities of their daily life, and finally of their legs themselves. Peripheral vascular disease has long been managed by the vascular surgeon utilizing endarterectomy and peripheral arterial bypass. Patient acceptance of nonsurgical, percutaneous procedures such as percutaneous transluminal balloon angioplasty (PTA) is high. Increased utilization of these procedures has led to improved techniques and adjuncts to therapy, as well as more critical review of long-term results. This article will review the evaluation and nonoperative management of PVD, with an emphasis on the newer modalities of management presently being investigated.

  5. Laser ablation of human atherosclerotic plaque without adjacent tissue injury

    NASA Technical Reports Server (NTRS)

    Grundfest, W. S.; Litvack, F.; Forrester, J. S.; Goldenberg, T.; Swan, H. J. C.

    1985-01-01

    Seventy samples of human cadaver atherosclerotic aorta were irradiated in vitro using a 308 nm xenon chloride excimer laser. Energy per pulse, pulse duration and frequency were varied. For comparison, 60 segments were also irradiated with an argon ion and an Nd:YAG laser operated in the continuous mode. Tissue was fixed in formalin, sectioned and examined microscopically. The Nd:YAG and argon ion-irradiated tissue exhibited a central crater with irregular edges and concentric zones of thermal and blast injury. In contrast, the excimer laser-irradiated tissue had narrow deep incisions with minimal or no thermal injury. These preliminary experiments indicate that the excimer laser vaporizes tissue in a manner different from that of the continuous wave Nd:YAG or argon ion laser. The sharp incision margins and minimal damage to adjacent normal tissue suggest that the excimer laser is more desirable for general surgical and intravascular uses than are the conventionally used medical lasers.

  6. Non-atherosclerotic vascular disease in the young.

    PubMed

    Camilo, Osvaldo; Goldstein, Larry B

    2005-10-01

    There are a large variety of non-atherosclerotic causes of ischemic stroke in the young. Arterial dissection, most commonly associated with non-traumatic causes, is among the most common. Both the carotid and vertebrobasilar circulations can be affected. The vasculitidies represent a rare, but potentially treatable series of conditions that can lead to stroke through diverse mechanisms. Moyamoya is a nonatherosclerotic, noninflammatory, nonamyloid vasculopathy characterized by chronic progressive stenosis or occlusion of the distal internal carotid arteries and/or proximal portions of the middle and/or anterior cerebral arteries. Moyamoya can be idiopathic (moyamoya disease) or the result of other conditions. An appreciation of the unusual causes of stroke in the young is important when considering secondary prevention measures.

  7. CD154: the atherosclerotic risk factor in rheumatoid arthritis?

    PubMed Central

    2013-01-01

    Atherosclerosis, now regarded as a chronic inflammatory disease of the arterial wall, and its clinical manifestations have increasingly been associated with rheumatoid arthritis (RA), supporting the notion that autoimmune diseases and vascular disorders share common etiological features. Indeed, evidence pertaining to this matter indicates that inflammation and its multiple components are the driving force behind the pathogenesis of these disorders. Interestingly, CD154 and its receptors have emerged as major players in the development of RA and atherosclerosis, which raises the possibility that this axis may represent an important biological link between both complications. Indeed, CD154 signaling elicits critical inflammatory responses that are common to the pathogenesis of both diseases. Here, we provide an overview of the traditional and disease-related interrelations between RA and vascular abnormalities, while focusing on CD154 as a potential mediator in the development of atherosclerotic events in RA patients. PMID:23433179

  8. The prevention and regression of atherosclerotic plaques: emerging treatments

    PubMed Central

    Kalanuria, Atul Ashok; Nyquist, Paul; Ling, Geoffrey

    2012-01-01

    Occlusive vascular diseases, such as sudden coronary syndromes, stroke, and peripheral arterial disease, are a huge burden on the health care systems of developed and developing countries. Tremendous advances have been made over the last few decades in the diagnosis and treatment of atherosclerotic diseases. Intravascular ultrasound has been able to provide detailed information of plaque anatomy and has been used in several studies to assess outcomes. The presence of atherosclerosis disrupts the normal protective mechanism provided by the endothelium and this mechanism has been implicated in the pathophysiology of coronary artery disease and stroke. Efforts are being put into the prevention of atherosclerosis, which has been shown to begin in childhood. This paper reviews the pathophysiology of atherosclerosis and discusses the current options available for the prevention and reversal of plaque formation. PMID:23049260

  9. Bilateral atherosclerotic internal carotid artery occlusion and recurrent ischaemic stroke.

    PubMed

    Amin, Osama S M

    2015-06-08

    Bilateral internal carotid artery occlusion (BICAO) is a rare disease that carries a gloomy prognosis. We report a case of a 52-year-old man who developed ischaemic infarction at the region of the right middle cerebral artery; he was found to have atherosclerotic occlusion of both internal carotid arteries on Doppler-duplex examination. He received medical treatment only. After 1 year, he developed a new infarction at the region of the left middle cerebral artery. Conventional angiography revealed bilateral occlusion of internal carotid arteries at their origin, approximately 50% stenosis of the common carotid bulbs and mild stenosis of the origin of external carotid arteries. The patient did not undergo any form of surgical revascularisation procedures and died of severe aspiration pneumonia approximately 2 months after the second stroke. BICAO portends a poor outcome and carries a risk of recurrent ischaemic events. The best management strategy for this vascular occlusion remains unclear.

  10. Lipid and protein maps defining arterial layers in atherosclerotic aorta

    PubMed Central

    Martin-Lorenzo, Marta; Balluff, Benjamin; Maroto, Aroa S.; Carreira, Ricardo J.; van Zeijl, Rene J.M.; Gonzalez-Calero, Laura; de la Cuesta, Fernando; Barderas, Maria G; Lopez-Almodovar, Luis F; Padial, Luis R; McDonnell, Liam A.; Vivanco, Fernando; Alvarez-Llamas, Gloria

    2015-01-01

    Subclinical atherosclerosis cannot be predicted and novel therapeutic targets are needed. The molecular anatomy of healthy and atherosclerotic tissue is pursued to identify ongoing molecular changes in atherosclerosis development. Mass Spectrometry Imaging (MSI) accounts with the unique advantage of analyzing proteins and metabolites (lipids) while preserving their original localization; thus two dimensional maps can be obtained. Main molecular alterations were investigated in a rabbit model in response to early development of atherosclerosis. Aortic arterial layers (intima and media) and calcified regions were investigated in detail by MALDI-MSI and proteins and lipids specifically defining those areas of interest were identified. These data further complement main findings previously published in J Proteomics (M. Martin-Lorenzo et al., J. Proteomics. (In press); M. Martin-Lorenzo et al., J. Proteomics 108 (2014) 465–468.) [1,2]. PMID:26217810

  11. Fluorescence characteristics of atherosclerotic plaque and malignant tumors

    NASA Astrophysics Data System (ADS)

    Andersson-Engels, Stefan; Baert, Luc; Berg, Roger; D'Hallewin, Marie-Ange; Johansson, Jonas; Stenram, Unne; Svanberg, Katarina; Svanberg, Sune

    1991-06-01

    Two series of investigations utilizing laser-induced fluorescence (LIF) in characterizing diseased tissue are presented. In one in vitro investigation the fluorescence from normal and atherosclerotically diseased arteries are studied. In another clinical study the fluorescence in vivo from superficial urinary bladder malignancies in patients who had received a low-dose injection of Hematoporphyrin Derivative (HpD) is investigated. Additionally, the fluorescence properties of L-tryptophan, collagen-I powder, elastin powder, nicotinamide adenine dinucleotide and (beta) -carothene were investigated and compared with the spectra from the tissue samples. A nitrogen laser (337 nm) alone or in connection with a dye laser (405 nm) was used together with an optical multichannel analyzer (OMA) to study the fluorescence spectra. The fluorescence decay characteristics of atherosclerotic plaque were examined utilizing a mode locked argon ion laser, synchronously pumping a picosecond dye laser. A fast detection system based on photon counting was employed. The fluorescence decay curves were evaluated on a PC computer allowing up to three lifetime components to be determined. A fluorescence peak at 390 nm in fibrotic plaque was identified as due to collagen fibers, while a fluorescence peak at 520 nm was connected to (beta) -carotene. The in vivo measurements of urinary bladder malignancies were performed with the optical fiber of the OMA system inserted through the biopsy channel of a cystoscope during the diagnostical procedure. The spectral recordings from urinary bladders, obtained at 337 nm and 405 nm excitation, revealed fluorescence features which can be used to demarcate tumor areas from normal mucosa. The fluorescence emission might also be useful to characterize different degrees of dysplasia.

  12. Scalability of the LEU-Modified Cintichem Process: 3-MeV Van de Graaff and 35-MeV Electron Linear Accelerator Studies

    SciTech Connect

    Rotsch, David A.; Brossard, Tom; Roussin, Ethan; Quigley, Kevin; Chemerisov, Sergey; Gromov, Roman; Jonah, Charles; Hafenrichter, Lohman; Tkac, Peter; Krebs, John; Vandegrift, George F.

    2016-10-31

    Molybdenum-99, the mother of Tc-99m, can be produced from fission of U-235 in nuclear reactors and purified from fission products by the Cintichem process, later modified for low-enriched uranium (LEU) targets. The key step in this process is the precipitation of Mo with α-benzoin oxime (ABO). The stability of this complex to radiation has been examined. Molybdenum-ABO was irradiated with 3 MeV electrons produced by a Van de Graaff generator and 35 MeV electrons produced by a 50 MeV/25 kW electron linear accelerator. Dose equivalents of 1.7–31.2 kCi of Mo-99 were administered to freshly prepared Mo-ABO. Irradiated samples of Mo-ABO were processed according to the LEU Modified-Cintichem process. The Van de Graaff data indicated good radiation stability of the Mo-ABO complex up to ~15 kCi dose equivalents of Mo-99 and nearly complete destruction at doses >24 kCi Mo-99. The linear accelerator data indicate that even at 6.2 kCi of Mo-99 equivalence of dose, the sample lost ~20% of Mo-99. The 20% loss of Mo-99 at this low dose may be attributed to thermal decomposition of the product from the heat deposited in the sample during irradiation.

  13. A Study of Variables That Affect Results in the ASTM D2274 Accelerated Stability Test. Part 1. Laboratory, Operator, and Process Variable Effects.

    DTIC Science & Technology

    1987-04-01

    indicator adsorption GC Gas chromatography HPLC High-pressure liquid chromatography Hz Hertz LCO Light-cycle oils L/hr Liters per hour urm Micrometers mg...Process- Var iah Ii’ F fee-t s P FLD CROUP I- SBGROUP h te IeO StI,1i Ii i t\\ P roe edtore DI) i f viCe *𔄃 AB RACT (Continue on reverSe *f necesSary and...34 APPENDIX A - QUESTIONNAIRE ON THE USE OF THE ASTM TEST FOR OXIDATION STABILITY OF DISTILLATE FUEL OIL (ACCELERATED

  14. LINEAR ACCELERATOR

    DOEpatents

    Colgate, S.A.

    1958-05-27

    An improvement is presented in linear accelerators for charged particles with respect to the stable focusing of the particle beam. The improvement consists of providing a radial electric field transverse to the accelerating electric fields and angularly introducing the beam of particles in the field. The results of the foregoing is to achieve a beam which spirals about the axis of the acceleration path. The combination of the electric fields and angular motion of the particles cooperate to provide a stable and focused particle beam.

  15. Using compute unified device architecture-enabled graphic processing unit to accelerate fast Fourier transform-based regression Kriging interpolation on a MODIS land surface temperature image

    NASA Astrophysics Data System (ADS)

    Hu, Hongda; Shu, Hong; Hu, Zhiyong; Xu, Jianhui

    2016-04-01

    Kriging interpolation provides the best linear unbiased estimation for unobserved locations, but its heavy computation limits the manageable problem size in practice. To address this issue, an efficient interpolation procedure incorporating the fast Fourier transform (FFT) was developed. Extending this efficient approach, we propose an FFT-based parallel algorithm to accelerate regression Kriging interpolation on an NVIDIA® compute unified device architecture (CUDA)-enabled graphic processing unit (GPU). A high-performance cuFFT library in the CUDA toolkit was introduced to execute computation-intensive FFTs on the GPU, and three time-consuming processes were redesigned as kernel functions and executed on the CUDA cores. A MODIS land surface temperature 8-day image tile at a resolution of 1 km was resampled to create experimental datasets at eight different output resolutions. These datasets were used as the interpolation grids with different sizes in a comparative experiment. Experimental results show that speedup of the FFT-based regression Kriging interpolation accelerated by GPU can exceed 1000 when processing datasets with large grid sizes, as compared to the traditional Kriging interpolation running on the CPU. These results demonstrate that the combination of FFT methods and GPU-based parallel computing techniques greatly improves the computational performance without loss of precision.

  16. Breakthrough: Fermilab Accelerator Technology

    ScienceCinema

    None

    2016-07-12

    There are more than 30,000 particle accelerators in operation around the world. At Fermilab, scientists are collaborating with other laboratories and industry to optimize the manufacturing processes for a new type of powerful accelerator that uses superconducting niobium cavities. Experimenting with unique polishing materials, a Fermilab team has now developed an efficient and environmentally friendly way of creating cavities that can propel particles with more than 30 million volts per meter.

  17. Section 7.3. accelerator facilities. Technology review of accelerator facilities

    NASA Astrophysics Data System (ADS)

    McKeown, Joseph

    New initiatives in basic science, accelerator engineering and market development, continue to stimulate applications of electron accelerators. Contributions from scientific experts in each of these segments have been assimulated to reflect the present status of accelerator technology in radiation processing.

  18. Acceleration switch

    DOEpatents

    Abbin, Jr., Joseph P.; Devaney, Howard F.; Hake, Lewis W.

    1982-08-17

    The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.

  19. Acceleration switch

    DOEpatents

    Abbin, J.P. Jr.; Devaney, H.F.; Hake, L.W.

    1979-08-29

    The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.

  20. ION ACCELERATOR

    DOEpatents

    Bell, J.S.

    1959-09-15

    An arrangement for the drift tubes in a linear accelerator is described whereby each drift tube acts to shield the particles from the influence of the accelerating field and focuses the particles passing through the tube. In one embodiment the drift tube is splii longitudinally into quadrants supported along the axis of the accelerator by webs from a yoke, the quadrants. webs, and yoke being of magnetic material. A magnetic focusing action is produced by energizing a winding on each web to set up a magnetic field between adjacent quadrants. In the other embodiment the quadrants are electrically insulated from each other and have opposite polarity voltages on adjacent quadrants to provide an electric focusing fleld for the particles, with the quadrants spaced sufficienily close enough to shield the particles within the tube from the accelerating electric field.

  1. Characterization of atherosclerotic plaque-depositions by infrared, Raman and CARS microscopy

    NASA Astrophysics Data System (ADS)

    Matthäus, Christian; Bergner, Gero; Krafft, Christoph; Dietzek, Benjamin; Romeike, Bernd F. M.; Brehm, Bernhard R.; Popp, Jürgen

    2011-07-01

    Atherosclerotic plaques are mainly composed of proteoglycans, triglycerides, cholesterol, cholesterolester and crystalline calcium. From histopathological characterizations it is known that the composition of these atherosclerotic plaques can vary to a great extent, due to different risk factors as smoking, hyperlipedemia, or genetic background ect. The individual plaque components can be spectroscopically easily identified. Furthermore, spectroscopic imaging technologies offer the possibility to study the plaque compositions in a more quantitative manner than traditional staining techniques. Here, we compare the potential of IR, Raman and CARS microscopy to characterize the constitution of atherosclerotic plaques as well as the structure of the surrounding tissue. For data analysis and image reconstruction spectral decomposition algorithms such as vertex component analysis (VCA) were introduced. The results are in good agreement with the histopathology. Aim of the study is to correlate the compositional characteristics of atherosclerotic plaques with individual disease patterns.

  2. LINEAR ACCELERATOR

    DOEpatents

    Christofilos, N.C.; Polk, I.J.

    1959-02-17

    Improvements in linear particle accelerators are described. A drift tube system for a linear ion accelerator reduces gap capacity between adjacent drift tube ends. This is accomplished by reducing the ratio of the diameter of the drift tube to the diameter of the resonant cavity. Concentration of magnetic field intensity at the longitudinal midpoint of the external sunface of each drift tube is reduced by increasing the external drift tube diameter at the longitudinal center region.

  3. M1 and M2 macrophage proteolytic and angiogenic profile analysis in atherosclerotic patients reveals a distinctive profile in type 2 diabetes.

    PubMed

    Roma-Lavisse, Charlotte; Tagzirt, Madjid; Zawadzki, Christophe; Lorenzi, Rodrigo; Vincentelli, André; Haulon, Stephan; Juthier, Francis; Rauch, Antoine; Corseaux, Delphine; Staels, Bart; Jude, Brigitte; Van Belle, Eric; Susen, Sophie; Chinetti-Gbaguidi, Giulia; Dupont, Annabelle

    2015-07-01

    This study aimed to investigate atherosclerotic mediators' expression levels in M1 and M2 macrophages and to focus on the influence of diabetes on M1/M2 profiles. Macrophages from 36 atherosclerotic patients (19 diabetics and 17 non-diabetics) were cultured with interleukin-1β (IL-1β) or IL-4 to induce M1 or M2 phenotype, respectively. The atherosclerotic mediators' expression was evaluated by quantitative reverse transcription-polymerase chain reaction (RT-PCR). The results showed that M1 and M2 macrophages differentially expressed mediators involved in proteolysis and angiogenesis processes. The proteolytic balance (matrix metalloproteinase-9 (MMP-9)/tissue inhibitor of metalloproteinase-1 (TIMP-1), MMP-9/plasminogen activator inhibitor-1 (PAI-1) and MMP-9/tissue factor pathway inhibitor-2 (TFPI-2) ratios) was higher in M1 versus M2, whereas M2 macrophages presented higher angiogenesis properties (increased vascular endothelial growth factor/TFPI-2 and tissue factor/TFPI-2 ratios). Moreover, M1 macrophages from diabetics displayed more important proangiogenic and proteolytic activities than non-diabetics. This study reveals that M1 and M2 macrophages could differentially modulate major atherosclerosis-related pathological processes. Moreover, M1 macrophages from diabetics display a deleterious phenotype that could explain the higher plaque vulnerability observed in these subjects.

  4. Mucosal Administration of Collagen V Ameliorates the Atherosclerotic Plaque Burden by Inducing Interleukin 35-dependent Tolerance.

    PubMed

    Park, Arick C; Huang, Guorui; Jankowska-Gan, Ewa; Massoudi, Dawiyat; Kernien, John F; Vignali, Dario A; Sullivan, Jeremy A; Wilkes, David S; Burlingham, William J; Greenspan, Daniel S

    2016-02-12

    We have shown previously that collagen V (col(V)) autoimmunity is a consistent feature of atherosclerosis in human coronary artery disease and in the Apoe(-/-) mouse model. We have also shown sensitization of Apoe(-/-) mice with col(V) to markedly increase the atherosclerotic burden, providing evidence of a causative role for col(V) autoimmunity in atherosclerotic pathogenesis. Here we sought to determine whether induction of immune tolerance to col(V) might ameliorate atherosclerosis, providing further evidence for a causal role for col(V) autoimmunity in atherogenesis and providing insights into the potential for immunomodulatory therapeutic interventions. Mucosal inoculation successfully induced immune tolerance to col(V) with an accompanying reduction in plaque burden in Ldlr(-/-) mice on a high-cholesterol diet. The results therefore demonstrate that inoculation with col(V) can successfully ameliorate the atherosclerotic burden, suggesting novel approaches for therapeutic interventions. Surprisingly, tolerance and reduced atherosclerotic burden were both dependent on the recently described IL-35 and not on IL-10, the immunosuppressive cytokine usually studied in the context of induced tolerance and amelioration of atherosclerotic symptoms. In addition to the above, using recombinant protein fragments, we were able to localize two epitopes of the α1(V) chain involved in col(V) autoimmunity in atherosclerotic Ldlr(-/-) mice, suggesting future courses of experimentation for the characterization of such epitopes.

  5. Production-passage-time approximation: a new approximation method to accelerate the simulation process of enzymatic reactions.

    PubMed

    Kuwahara, Hiroyuki; Myers, Chris J

    2008-09-01

    Given the substantial computational requirements of stochastic simulation, approximation is essential for efficient analysis of any realistic biochemical system. This paper introduces a new approximation method to reduce the computational cost of stochastic simulations of an enzymatic reaction scheme which in biochemical systems often includes rapidly changing fast reactions with enzyme and enzyme-substrate complex molecules present in very small counts. Our new method removes the substrate dissociation reaction by approximating the passage time of the formation of each enzyme-substrate complex molecule which is destined to a production reaction. This approach skips the firings of unimportant yet expensive reaction events, resulting in a substantial acceleration in the stochastic simulations of enzymatic reactions. Additionally, since all the parameters used in our new approach can be derived by the Michaelis-Menten parameters which can actually be measured from experimental data, applications of this approximation can be practical even without having full knowledge of the underlying enzymatic reaction. Here, we apply this new method to various enzymatic reaction systems, resulting in a speedup of orders of magnitude in temporal behavior analysis without any significant loss in accuracy. Furthermore, we show that our new method can perform better than some of the best existing approximation methods for enzymatic reactions in terms of accuracy and efficiency.

  6. Application of a low level, uniform ultrasound field for the acceleration of enzymatic bio-processing of cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Enzymatic bio-processing of cotton generates significantly less hazardous wastewater effluents, which are readily biodegradable, but it also has several critical shortcomings that impede its acceptance by industries: expensive processing costs and slow reaction rates. Our research has found that th...

  7. Principles of Induction Accelerators

    NASA Astrophysics Data System (ADS)

    Briggs*, Richard J.

    The basic concepts involved in induction accelerators are introduced in this chapter. The objective is to provide a foundation for the more detailed coverage of key technology elements and specific applications in the following chapters. A wide variety of induction accelerators are discussed in the following chapters, from the high current linear electron accelerator configurations that have been the main focus of the original developments, to circular configurations like the ion synchrotrons that are the subject of more recent research. The main focus in the present chapter is on the induction module containing the magnetic core that plays the role of a transformer in coupling the pulsed power from the modulator to the charged particle beam. This is the essential common element in all these induction accelerators, and an understanding of the basic processes involved in its operation is the main objective of this chapter. (See [1] for a useful and complementary presentation of the basic principles in induction linacs.)

  8. Deficiency of AXL in Bone Marrow-Derived Cells Does Not Affect Advanced Atherosclerotic Lesion Progression.

    PubMed

    Subramanian, Manikandan; Proto, Jonathan D; Matsushima, Glenn K; Tabas, Ira

    2016-12-13

    AXL, a member of the TAM (Tyro3, Axl, MerTK) family of receptors, plays important roles in cell survival, clearance of dead cells (efferocytosis), and suppression of inflammation, which are processes that critically influence atherosclerosis progression. Whereas MerTK deficiency promotes defective efferocytosis, inflammation, and plaque necrosis in advanced murine atherosclerosis, the role of Axl in advanced atherosclerosis progression is not known. Towards this end, bone marrow cells from Axl(-/-) or wild-type mice were transplanted into lethally irradiated Ldlr(-/-) mice. These chimeric mice were then fed the Western-type diet (WD) for 17 weeks. We demonstrate that lesional macrophages in WT mice express Axl but that Axl deficiency in bone marrow-derived cells does not affect lesion size, cellularity, necrosis, or inflammatory parameters in advanced atherosclerotic plaques. Moreover, apoptosis of lesional cells was unaffected, and we found no evidence of defective lesional efferocytosis. In contrast to previously reported findings with MerTK deficiency, hematopoietic cell-Axl deficiency in WD-fed Ldlr(-/-) mice does not affect the progression of advanced atherosclerosis or lesional processes associated with TAM receptor signaling. These findings suggest a heretofore unappreciated TAM receptor hierarchy in advanced atherosclerosis.

  9. Application of an Integrative Computational Framework in Trancriptomic Data of Atherosclerotic Mice Suggests Numerous Molecular Players

    PubMed Central

    Papadodima, Olga; Sirsjö, Allan; Kolisis, Fragiskos N.; Chatziioannou, Aristotelis

    2012-01-01

    Atherosclerosis is a multifactorial disease involving a lot of genes and proteins recruited throughout its manifestation. The present study aims to exploit bioinformatic tools in order to analyze microarray data of atherosclerotic aortic lesions of ApoE knockout mice, a model widely used in atherosclerosis research. In particular, a dynamic analysis was performed among young and aged animals, resulting in a list of 852 significantly altered genes. Pathway analysis indicated alterations in critical cellular processes related to cell communication and signal transduction, immune response, lipid transport, and metabolism. Cluster analysis partitioned the significantly differentiated genes in three major clusters of similar expression profile. Promoter analysis applied to functional related groups of the same cluster revealed shared putative cis-elements potentially contributing to a common regulatory mechanism. Finally, by reverse engineering the functional relevance of differentially expressed genes with specific cellular pathways, putative genes acting as hubs, were identified, linking functionally disparate cellular processes in the context of traditional molecular description. PMID:23193398

  10. Deficiency of AXL in Bone Marrow-Derived Cells Does Not Affect Advanced Atherosclerotic Lesion Progression

    PubMed Central

    Subramanian, Manikandan; Proto, Jonathan D.; Matsushima, Glenn K.; Tabas, Ira

    2016-01-01

    AXL, a member of the TAM (Tyro3, Axl, MerTK) family of receptors, plays important roles in cell survival, clearance of dead cells (efferocytosis), and suppression of inflammation, which are processes that critically influence atherosclerosis progression. Whereas MerTK deficiency promotes defective efferocytosis, inflammation, and plaque necrosis in advanced murine atherosclerosis, the role of Axl in advanced atherosclerosis progression is not known. Towards this end, bone marrow cells from Axl−/− or wild-type mice were transplanted into lethally irradiated Ldlr−/− mice. These chimeric mice were then fed the Western-type diet (WD) for 17 weeks. We demonstrate that lesional macrophages in WT mice express Axl but that Axl deficiency in bone marrow-derived cells does not affect lesion size, cellularity, necrosis, or inflammatory parameters in advanced atherosclerotic plaques. Moreover, apoptosis of lesional cells was unaffected, and we found no evidence of defective lesional efferocytosis. In contrast to previously reported findings with MerTK deficiency, hematopoietic cell-Axl deficiency in WD-fed Ldlr−/− mice does not affect the progression of advanced atherosclerosis or lesional processes associated with TAM receptor signaling. These findings suggest a heretofore unappreciated TAM receptor hierarchy in advanced atherosclerosis. PMID:27958361

  11. The Impact of Macrophage Insulin Resistance on Advanced Atherosclerotic Plaque Progression

    PubMed Central

    Tabas, Ira; Tall, Alan; Accili, Domenico

    2009-01-01

    Atherothrombotic vascular disease is the major cause of death and disability in obese and diabetic subjects with insulin resistance. Although increased systemic risk factors in the setting of insulin resistance contribute to this problem, it is likely exacerbated by direct effects of insulin resistance on the arterial wall cells that participate in atherosclerosis. A critical process in the progression of atherosclerotic lesions to those that cause clinical disease is necrotic breakdown of plaques. Plaque necrosis, which is particularly prominent in the lesions of diabetics, is caused by the combination of macrophage apoptosis and defective clearance, or efferocytosis, of the apoptotic macrophages. One cause of macrophage apoptosis in advanced plaques is activation of a pro-apoptotic branch of the endoplasmic reticulum stress pathway known as the Unfolded Protein Response (UPR). Macrophages have a functional insulin receptor signal transduction pathway, and down regulation of this pathway in the setting insulin resistance enhances UPR-induced apoptosis. Moreover, other aspects of the obesity/insulin-resistance syndrome may adversely affect efferocytosis. These processes may therefore provide an important mechanistic link among insulin resistance, plaque necrosis, and atherothrombotic vascular disease and suggest novel therapeutic approaches to this expanding health problem. PMID:20056946

  12. Emergency EC-IC bypass for symptomatic atherosclerotic ischemic stroke.

    PubMed

    Horiuchi, Tetsuyoshi; Nitta, Junpei; Ishizaka, Shigetoshi; Kanaya, Kohei; Yanagawa, Takao; Hongo, Kazuhiro

    2013-10-01

    Previous studies have shown that extracranial-intracranial (EC-IC) bypass surgery has no preventive effect on subsequent ipsilateral ischemic stroke in patients with symptomatic atherosclerotic internal carotid occlusion and hemodynamic cerebral ischemia. A few studies have assessed whether an urgent EC-IC bypass surgery is an effective treatment for main trunk stenosis or occlusion in acute stage. The authors retrospectively reviewed 58 consecutive patients who underwent urgent EC-IC bypass for symptomatic internal carotid artery or the middle cerebral artery stenosis or occlusion between January 2003 and December 2011. Clinical characteristics and neuroimagings were evaluated and analyzed. Based on preoperative angiogram, responsible lesions were the internal carotid artery in 19 (32.8%) patients and the middle cerebral artery in 39 (67.2%). No hemorrhagic complication occurred. Sixty-nine percent of patients showed improvement of neurological function after surgery, and 74.1% of patients had favorable outcome. Unfavorable outcome was associated with insufficient collateral flow and new infarction after bypass surgery.

  13. Mechanical functional role of non-atherosclerotic intimal thickening.

    PubMed

    Glagov, S; Zarins, C K; Masawa, N; Xu, C P; Bassiouny, H; Giddens, D P

    1993-01-01

    Arteries adjust to alterations in wall shear stress or tensile stress by changes in diameter, wall thickness, structure and composition. The intima participates in these adaptive reactions, particularly when changes in mechanical stresses are imposed after physiologic stress levels have been established during growth. Decreased wall shear stress due to decreased flow, flow separation or complex flow patterns, or increases in tensile stress due to increases in pressure or radius stimulate non-atherosclerotic intimal proliferation. Intimal fibrocellular hypertrophy (IFH), in the form of compact fibrocellular layers resembling the media, stabilizes when the lumen diameter is reduced sufficiently or wall thickness is increased sufficiently to restore baseline wall shear or tensile stress. Reactive-adaptive intimal proliferation is not necessarily self-limiting and may continue in the form of intimal hyperplasia (IH) which is relatively matrix-free and poorly organized. If mural and intimal changes do not result in restoration of baseline wall shear and tensile stress, IH may proceed to further narrowing and stenosis. Identification of the cellular and molecular mechanisms which underly the responses which link flow to diameter, diameter and pressure to mural restructuring, and mural restructuring to intimal thickening should provide new insights into the nature of vessel adaptations in the absence or presence of atherogenesis.

  14. Paramagnetic Manganese in the Atherosclerotic Plaque of Carotid Arteries

    PubMed Central

    Chelyshev, Yury; Ignatyev, Igor; Zanochkin, Alexey; Mamin, Georgy; Sorokin, Boris; Sorokina, Alexandra; Lyapkalo, Natalya; Gizatullina, Nazima; Orlinskii, Sergei

    2016-01-01

    The search for adequate markers of atherosclerotic plaque (AP) instability in the context of assessment of the ischemic stroke risk in patients with atherosclerosis of the carotid arteries as well as for solid physical and chemical factors that are connected with the AP stability is extremely important. We investigate the inner lining of the carotid artery specimens from the male patients with atherosclerosis (27 patients, 42–64 years old) obtained during carotid endarterectomy by using different analytical tools including ultrasound angiography, X-ray analysis, immunological, histochemical analyses, and high-field (3.4 T) pulse electron paramagnetic resonance (EPR) at 94 GHz. No correlation between the stable and unstable APs in the sense of the calcification is revealed. In all of the investigated samples, the EPR spectra of manganese, namely, Mn2+ ions, are registered. Spectral and relaxation characteristics of Mn2+ ions are close to those obtained for the synthetic (nano) hydroxyapatite species but differ from each other for stable and unstable APs. This demonstrates that AP stability could be specified by the molecular organization of their hydroxyapatite components. The origin of the obtained differences and the possibility of using EPR of Mn2+ as an AP stability marker are discussed. PMID:28078287

  15. Preventing restenosis in atherosclerotic miniswine with photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Hsiang, York N.; Crespo, M. T.; To, Eleanor C.; Sobeh, Mohammed S.; Greenwald, Stephen E.; Bower, Robert D.

    1995-05-01

    The purpose of this study was to determine whether the addition of Photodynamic Therapy (PDT) using the photosensitizer Photofrin* (P*) following balloon angioplasty (BA) could prevent restenosis in an atherosclerotic animal model. Bilateral iliac atherosclerosis was created in 21 Yucatan miniswine. Six weeks later, P* 2.5 mg/kg was given IV 24 hours prior to BA (4 mm X 20 mm, 1 inflation). Following BA, swine were randomly allocated to receive PDT via a fiberoptic probe with laser energy or the same probe without laser energy. The fiberoptic probe had a 1 cm cylindrical diffusing tip and was passed co-axially through a custom catheter to ensure central location of the probe. A continuous wave argon ion-pumped dye laser tuned to 630 nm was used to provide a fluence of 100 J/cm2. Four weeks later, swine were sacrificed and vessels perfusion-fixed in-situ with glutaraldehyde and analyzed by ocular micrometry. Five occlusions occurred, all in the PDT + BA group. Percentage intimal thickness (mean +/- SD) was 51.0 +/- 29.5 in the BA group and 71.2 +/- 35.2 in the BA + PDT group (p equals 0.21). These results suggest that the addition of PDT following BA does not prevent restenosis.

  16. Multimodal spectroscopy detects features of vulnerable atherosclerotic plaque

    NASA Astrophysics Data System (ADS)

    Šćepanović, Obrad R.; Fitzmaurice, Maryann; Miller, Arnold; Kong, Chae-Ryon; Volynskaya, Zoya; Dasari, Ramachandra R.; Kramer, John R.; Feld, Michael S.

    2011-01-01

    Early detection and treatment of rupture-prone vulnerable atherosclerotic plaques is critical to reducing patient mortality associated with cardiovascular disease. The combination of reflectance, fluorescence, and Raman spectroscopy-termed multimodal spectroscopy (MMS)-provides detailed biochemical information about tissue and can detect vulnerable plaque features: thin fibrous cap (TFC), necrotic core (NC), superficial foam cells (SFC), and thrombus. Ex vivo MMS spectra are collected from 12 patients that underwent carotid endarterectomy or femoral bypass surgery. Data are collected by means of a unitary MMS optical fiber probe and a portable clinical instrument. Blinded histopathological analysis is used to assess the vulnerability of each spectrally evaluated artery lesion. Modeling of the ex vivo MMS spectra produce objective parameters that correlate with the presence of vulnerable plaque features: TFC with fluorescence parameters indicative of collagen presence; NC/SFC with a combination of diffuse reflectance β-carotene/ceroid absorption and the Raman spectral signature of lipids; and thrombus with its Raman signature. Using these parameters, suspected vulnerable plaques can be detected with a sensitivity of 96% and specificity of 72%. These encouraging results warrant the continued development of MMS as a catheter-based clinical diagnostic technique for early detection of vulnerable plaques.

  17. Experimental Studies of Two Replicated Atherosclerotic Carotid Bifurcations

    NASA Astrophysics Data System (ADS)

    Bale-Glickman, Jocelyn; Selby, Kathy; Saloner, David; Savas, Omer

    2004-11-01

    Detailed flow visualization and particle image velocimetry (PIV) studies are carried out at the stenosis in two atherosclerotic carotid bifurcation models under physiological flow conditions. Companion experiments are also carried out with sinusoidal and steady input flows. The complex internal geometry of the diseased artery combined with pulsatile input flows gives complex, model-specific flow patterns, with details that vary from cycle to cycle. Both models show a jet leaving the stenosis, with an associated recirculation zone on one side. Other flow features include separation points, recirculation zones, internal jets, three-dimensional shear layers, and stagnation lines. The wall shear stresses (WSS) are estimated from the PIV data. The profile WSS along the arterial lumen is unique for each artery, but similar profiles are observed for both physiological and steady flow for each artery. The WSS at the narrowest point in the stenotic neck varies chaotically from cycle to cycle, but typically ranges from 5 Pa to -40 Pa. The peak WSS values are found at peak systole.

  18. Aldehyde dehydrogenase 2 inhibits inflammatory response and regulates atherosclerotic plaque

    PubMed Central

    Wei, Shu-jian; Zhang, Ming-xiang; Wang, Xu-ping; Yuan, Qiu-huan; Xue, Li; Wang, Jia-li; Cui, Zhao-qiang; Zhang, Yun; Xu, Feng; Chen, Yu-guo

    2016-01-01

    Previous studies demonstrated that aldehyde dehydrogenase 2 (ALDH2) rs671 polymorphism, which eliminates ALDH2 activity down to 1%-6%, is a susceptibility gene for coronary disease. Here we investigated the underlying mechanisms based on our prior clinical and experimental studies. Male apoE−/− mice were transfected with GFP, ALDH2-overexpression and ALDH2-RNAi lentivirus respectively (n=20 each) after constrictive collars were placed around the right common carotid arteries. Consequently, ALDH2 gene silencing led to an increased en face plaque area, more unstable plaque with heavier accumulation of lipids, more macrophages, less smooth muscle cells and collagen, which were associated with aggravated inflammation. However, ALDH2 overexpression displayed opposing effects. We also found that ALDH2 activity decreased in atherosclerotic plaques of human and aged apoE−/− mice. Moreover, in vitro experiments with human umbilical vein endothelial cells further illustrated that, inhibition of ALDH2 activity resulted in elevating inflammatory molecules, an increase of nuclear translocation of NF-κB, and enhanced phosphorylation of NF-κB p65, AP-1 c-Jun, Jun-N terminal kinase and p38 MAPK, while ALDH2 activation could trigger contrary effects. These findings suggested that ALDH2 can influence plaque development and vulnerability, and inflammation via MAPK, NF-κB and AP-1 signaling pathways. PMID:27191745

  19. Primary Prevention of Atherosclerotic Cardiovascular Disease in Women

    PubMed Central

    McKibben, Rebeccah A.; Al Rifai, Mahmoud; Mathews, Lena M.; Michos, Erin D.

    2016-01-01

    Atherosclerotic cardiovascular disease (ASCVD) is the leading cause of morbidity and mortality among women. Despite improvements in cardiovascular disease prevention efforts, there remain gaps in cardiovascular disease awareness among women, as well as age and racial disparities in ASCVD outcomes for women. Disparity also exists in the impact the traditional risk factors confer on ASCVD risk between women and men, with smoking and diabetes both resulting in stronger relative risks in women compared to men. Additionally there are risk factors that are unique to women (such as pregnancy-related factors) or that disproportionally affect women (such as auto-immune disease) where preventive efforts should be targeted. Risk assessment and management must also be sex-specific to effectively reduce cardiovascular disease and improve outcomes among women. Evidence supports the use of statin therapy for primary prevention in women at higher ASCVD risk. However, some pause should be given to prescribing aspirin therapy in women without known ASCVD, with most evidence supporting the use of aspirin for women≥65 years not at increased risk for bleeding. This review article will summarize (1) traditional and non-traditional assessments of ASCVD risk and (2) lifestyle and pharmacologic therapies for the primary prevention of ASCVD in women. PMID:28149430

  20. [Management of atherosclerotic renal-artery stenosis in 2016].

    PubMed

    Fournier, Thomas; Sens, Florence; Rouvière, Olivier; Millon, Antoine; Juillard, Laurent

    2017-02-01

    Endovascular revascularization as treatment of atherosclerotic renal-artery stenosis (aRAS) is controversial since 3 large and multicentric randomised trials (CORAL, ASTRAL, STAR) failed to prove the superiority of percutaneous transluminal renal-artery stenting (PTRAS) over medical treatment only (MT). However, considering the multiple bias of these trials, among which questionable inclusion criterias, these results must be extrapolated in clinical practice with caution. New pathophysiological data have been helping to understand why restoring blood flow does not necessarily lead to kidney function improvement. Today, the diagnostic approach must in one hand confirm the artery stenosis and on the other hand assess its severity and impact on the kidney. Therapeutic options still lie on the American guidelines published in 2006, since no study data can be reasonably used in everyday practice. However, particular sub-groups of patients who could benefit from revascularisation have been identified through recent cohort studies. Further prospective studies are needed in order to confirm the superiority of PTRAS in these populations. Meanwhile, multidisciplinary approach should be promoted, in order to provide the best treatment for each patient.

  1. Directional spatial frequency analysis of lipid distribution in atherosclerotic plaque

    NASA Astrophysics Data System (ADS)

    Korn, Clyde; Reese, Eric; Shi, Lingyan; Alfano, Robert; Russell, Stewart

    2016-04-01

    Atherosclerosis is characterized by the growth of fibrous plaques due to the retention of cholesterol and lipids within the artery wall, which can lead to vessel occlusion and cardiac events. One way to evaluate arterial disease is to quantify the amount of lipid present in these plaques, since a higher disease burden is characterized by a higher concentration of lipid. Although therapeutic stimulation of reverse cholesterol transport to reduce cholesterol deposits in plaque has not produced significant results, this may be due to current image analysis methods which use averaging techniques to calculate the total amount of lipid in the plaque without regard to spatial distribution, thereby discarding information that may have significance in marking response to therapy. Here we use Directional Fourier Spatial Frequency (DFSF) analysis to generate a characteristic spatial frequency spectrum for atherosclerotic plaques from C57 Black 6 mice both treated and untreated with a cholesterol scavenging nanoparticle. We then use the Cauchy product of these spectra to classify the images with a support vector machine (SVM). Our results indicate that treated plaque can be distinguished from untreated plaque using this method, where no difference is seen using the spatial averaging method. This work has the potential to increase the effectiveness of current in-vivo methods of plaque detection that also use averaging methods, such as laser speckle imaging and Raman spectroscopy.

  2. Primary Prevention of Atherosclerotic Cardiovascular Disease in Women.

    PubMed

    McKibben, Rebeccah A; Al Rifai, Mahmoud; Mathews, Lena M; Michos, Erin D

    2016-01-01

    Atherosclerotic cardiovascular disease (ASCVD) is the leading cause of morbidity and mortality among women. Despite improvements in cardiovascular disease prevention efforts, there remain gaps in cardiovascular disease awareness among women, as well as age and racial disparities in ASCVD outcomes for women. Disparity also exists in the impact the traditional risk factors confer on ASCVD risk between women and men, with smoking and diabetes both resulting in stronger relative risks in women compared to men. Additionally there are risk factors that are unique to women (such as pregnancy-related factors) or that disproportionally affect women (such as auto-immune disease) where preventive efforts should be targeted. Risk assessment and management must also be sex-specific to effectively reduce cardiovascular disease and improve outcomes among women. Evidence supports the use of statin therapy for primary prevention in women at higher ASCVD risk. However, some pause should be given to prescribing aspirin therapy in women without known ASCVD, with most evidence supporting the use of aspirin for women≥65 years not at increased risk for bleeding. This review article will summarize (1) traditional and non-traditional assessments of ASCVD risk and (2) lifestyle and pharmacologic therapies for the primary prevention of ASCVD in women.

  3. Phenotypic alterations in human saphenous vein culture induced by tumor necrosis factor-alpha and lipoproteins: a preliminary development of an initial atherosclerotic plaque model

    PubMed Central

    2013-01-01

    Background Atherosclerosis is a chronic progressive inflammatory disease of blood vessels particularly the arteries. The development of atherosclerotic plaques or atherogenesis is a complex process that is influenced by cardiovascular risk factors such as vascular inflammation and dyslipidemia. This study demonstrates the ability of tumor necrosis factor-alpha (TNF-α) and low density lipoproteins (LDL) to induce atherosclerotic plaque in human saphenous vein (HSV) organ culture. Methods Normal HSV segments, from male patients who had coronary bypass graft, were cultured in DMEM containing 5% heat inactivated fetal bovine serum. TNF-α (5 ng/ml) was applied in combination with native LDL (nLDL) or oxidized LDL (oxLDL) at the dose of 50 μg/ml for 14 days. The phenotypic changes of the organ cultures characteristic of initial atherosclerotic plaques were evaluated. The effect of anti-atherogenic agent, 17-β estradiol (E2), was also determined. Results Histologic, histomorphometric, and immunohistochemical examinations revealed that HSV rings stimulated with TNF-α + nLDL or TNF-α + oxLDL can exhibit the essential morphological features of atherogenesis, including fibrous cap formation, cholesterol clefts, evident thickening of the intimal layer, increased proliferation of smooth muscle cells (SMC) and migration to the subendothelial layer, significant SMC foam cell formation, and increased expression of adhesion molecules in the vascular wall. Addition of E2 (50 nM) to the culture significantly modulated the critical changes. Consistently, mRNA profiling of the HSV model revealed that 50 of 84 genes of atherosclerosis were up-regulated. Conclusions Phenotypic changes characteristic of the initial development of atherosclerotic plaques can be induced in HSV organ culture. PMID:24010774

  4. Acceleration Studies

    NASA Technical Reports Server (NTRS)

    Rogers, Melissa J. B.

    1993-01-01

    Work to support the NASA MSFC Acceleration Characterization and Analysis Project (ACAP) was performed. Four tasks (analysis development, analysis research, analysis documentation, and acceleration analysis) were addressed by parallel projects. Work concentrated on preparation for and implementation of near real-time SAMS data analysis during the USMP-1 mission. User support documents and case specific software documentation and tutorials were developed. Information and results were presented to microgravity users. ACAP computer facilities need to be fully implemented and networked, data resources must be cataloged and accessible, future microgravity missions must be coordinated, and continued Orbiter characterization is necessary.

  5. Particle acceleration

    NASA Technical Reports Server (NTRS)

    Vlahos, L.; Machado, M. E.; Ramaty, R.; Murphy, R. J.; Alissandrakis, C.; Bai, T.; Batchelor, D.; Benz, A. O.; Chupp, E.; Ellison, D.

    1986-01-01

    Data is compiled from Solar Maximum Mission and Hinothori satellites, particle detectors in several satellites, ground based instruments, and balloon flights in order to answer fundamental questions relating to: (1) the requirements for the coronal magnetic field structure in the vicinity of the energization source; (2) the height (above the photosphere) of the energization source; (3) the time of energization; (4) transistion between coronal heating and flares; (5) evidence for purely thermal, purely nonthermal and hybrid type flares; (6) the time characteristics of the energization source; (7) whether every flare accelerates protons; (8) the location of the interaction site of the ions and relativistic electrons; (9) the energy spectra for ions and relativistic electrons; (10) the relationship between particles at the Sun and interplanetary space; (11) evidence for more than one acceleration mechanism; (12) whether there is single mechanism that will accelerate particles to all energies and also heat the plasma; and (13) how fast the existing mechanisms accelerate electrons up to several MeV and ions to 1 GeV.

  6. Plasma accelerator

    DOEpatents

    Wang, Zhehui; Barnes, Cris W.

    2002-01-01

    There has been invented an apparatus for acceleration of a plasma having coaxially positioned, constant diameter, cylindrical electrodes which are modified to converge (for a positive polarity inner electrode and a negatively charged outer electrode) at the plasma output end of the annulus between the electrodes to achieve improved particle flux per unit of power.

  7. Accelerated Achievement

    ERIC Educational Resources Information Center

    Ford, William J.

    2010-01-01

    This article focuses on the accelerated associate degree program at Ivy Tech Community College (Indiana) in which low-income students will receive an associate degree in one year. The three-year pilot program is funded by a $2.3 million grant from the Lumina Foundation for Education in Indianapolis and a $270,000 grant from the Indiana Commission…

  8. ACCELERATION INTEGRATOR

    DOEpatents

    Pope, K.E.

    1958-01-01

    This patent relates to an improved acceleration integrator and more particularly to apparatus of this nature which is gyrostabilized. The device may be used to sense the attainment by an airborne vehicle of a predetermined velocitv or distance along a given vector path. In its broad aspects, the acceleration integrator utilizes a magnetized element rotatable driven by a synchronous motor and having a cylin drical flux gap and a restrained eddy- current drag cap deposed to move into the gap. The angular velocity imparted to the rotatable cap shaft is transmitted in a positive manner to the magnetized element through a servo feedback loop. The resultant angular velocity of tae cap is proportional to the acceleration of the housing in this manner and means may be used to measure the velocity and operate switches at a pre-set magnitude. To make the above-described dcvice sensitive to acceleration in only one direction the magnetized element forms the spinning inertia element of a free gyroscope, and the outer housing functions as a gimbal of a gyroscope.

  9. Generic chromatography-based purification strategies accelerate the development of downstream processes for biopharmaceutical proteins produced in plants.

    PubMed

    Buyel, Johannes F; Fischer, Rainer

    2014-04-01

    Plants offer a valuable alternative to cultured mammalian cells for the production of recombinant biopharmaceutical proteins. However, the target protein typically represents only a minor fraction of the total protein in the initial plant extract, which means that the development of product-specific chromatography-based purification strategies is often laborious and expensive. To address this challenge, we designed a generic downstream process that is suitable for the purification of recombinant proteins with diverse properties from plant production platforms. This was achieved by focusing on the binding behavior of tobacco host cell proteins (HCPs) to a broad set of chromatography resins under different pH and conductivity conditions. Strong cation exchanger and salt-tolerant anion exchanger resins exhibited the best resolution of tobacco HCPs among the 13 tested resins, and their selectivity was easy to manipulate through the adjustment of pH and conductivity. The advantages, such as direct capture of a target protein from leaf extract, and limitations, such as low binding capacity, of various chromatography ligands and resins are discussed. We also address the most useful applications of the chromatography ligands, namely recovery of proteins with a certain pI, in a downstream process that aims to purify diverse plant-derived biopharmaceutical proteins. Based on these results, we describe generic purification schemes that are suitable for acidic, neutral, and basic target proteins, as a first step toward the development of industrial platform processes.

  10. DNA and RNA isolated from tissues processed by microwave-accelerated apparatus MFX-800-3 are suitable for subsequent PCR and Q-RT-PCR amplification.

    PubMed

    Bödör, Csaba; Schmidt, Otto; Csernus, Balázs; Rajnai, Hajnalka; Szende, Béla

    2007-01-01

    Over the past decade, methods of molecular biology have appeared in diagnostic pathology and are routinely applied on formalin-fixed, paraffin-embedded histological samples, processed via conventional embedding methods. Due to its reagent- and cost-effectiveness, embedding techniques that utilize microwave acceleration in one or more steps of histoprocessing are increasingly used by numerous laboratories. The demand arises that tissues processed this way should also be suitable for the requirements of molecular pathology. In this study, both conventionally embedded and MFX-800-3 machine-processed tissue samples from the same source were used for isolation of DNA and RNA and for performing PCR and real-time PCR. PCR amplification of the beta-globin gene, as well as the real-time PCR amplification of the ABL mRNA was successful in all cases. Our conclusion is that samples processed by the vacuum assisted automatic microwave histoprocessor MFX-800-3 are perfectly applicable for DNA and RNA isolation and provide appropriate templates for further PCR and realtime PCR studies.

  11. From Cleanup to Stewardship. A companion report to Accelerating Cleanup: Paths to Closure and background information to support the scoping process required for the 1998 PEIS Settlement Study

    SciTech Connect

    None, None

    1999-10-01

    Long-term stewardship is expected to be needed at more than 100 DOE sites after DOE's Environmental Management program completes disposal, stabilization, and restoration operations to address waste and contamination resulting from nuclear research and nuclear weapons production conducted over the past 50 years. From Cleanup to stewardship provides background information on the Department of Energy (DOE) long-term stewardship obligations and activities. This document begins to examine the transition from cleanup to long-term stewardship, and it fulfills the Secretary's commitment to the President in the 1999 Performance Agreement to provide a companion report to the Department's Accelerating Cleanup: Paths to Closure report. It also provides background information to support the scoping process required for a study on long-term stewardship required by a 1998 Settlement Agreement.

  12. Mechanical modeling of cholesterol crystallization in atherosclerotic plaques base on Micro-OCT images (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Luo, Yuemei; Liu, Xinyu; Chen, Si; Cui, Dongyao; Wang, Xianghong; Liu, Linbo

    2016-02-01

    Plaque rupture is the critical cause of cardiovascular thrombosis but this process is still under discussion. Recent studies show that, during crystallization, cholesterol crystals in atheromatous plaques accumulate rapidly in a limited space and may result in plaque rupture. However, the actual role of cholesterol crystals on plaque rupture remains unclear due to the lack of detailed morphological information of cholesterol crystals. In this study, we used a Micro-optical coherence tomography (µOCT) setup with 1-2 µm spatial resolution to extract the geometry of cholesterol crystals from human atherosclerotic artery ex vivo firstly. With measured dimensions of cholesterol crystals by this µOCT system (the average length and thickness of 269.1±80.16 µm and 3.0±0.33 µm), we developed a two-dimensional mechanical model in which rectangular shaped cholesterol crystals distribute at different locations spatially. We predicted the stress on the thin cap induced by the expansion of cholesterol crystals by use of finite-element method. Since a large portion of plaques (58%) rupture at points of peak circumferential stress (PCS), we used PCS as the primary indicator of plaque stability with blood pressure of 14.6 kPa on the lumen. The results demonstrate that loading of the concentrated crystals especially at the cap shoulder destabilize the plaque by proportionally increasing the PCS, while evenly distributed crystals loading along the cap might impose less PCS to the plaque than the concentrated case.

  13. Automatic classification of atherosclerotic plaques imaged with intravascular OCT (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Rico-Jimenez, Jose D.; Campos-Delgado, Daniel U.; Villiger, Martin; Bouma, Brett; Jo, Javier A.

    2016-03-01

    A novel computational method for plaque tissue characterization based on Intravascular Optical Coherence Tomography (IV-OCT) is presented. IV-OCT is becoming a powerful tool for the clinical evaluation of atherosclerotic plaques; however, it requires a trained expert for visual assessment and interpretation of the imaged plaques. Moreover, due to the inherit effect of speckle and the scattering attenuation of the optical scheme the direct interpretation of OCT images is limited. To overcome these difficulties, we propose to automatically identify the A-line profiles of the most significant plaque types (normal, fibrotic, or lipid-rich) and their respective abundance by using a probabilistic framework and blind alternated least squares to achieve the optimal decomposition. In this context, we present preliminary results of this novel probabilistic classification tool for intravascular OCT that relies on two steps. First, the B-scan is pre-processed to remove catheter artifacts, segment the lumen, select the region of interest (ROI), flatten the tissue surface, and reduce the speckle effect by a spatial entropy filter. Next, the resulting image is decomposed and its A-lines are classified by an automated strategy based on alternating-least-squares optimization. Our early results are encouraging and suggest that the proposed methodology can identify normal tissue, fibrotic and lipid-rich plaques from IV-OCT images.

  14. Calibration of the Pooled Cohort Equations for Atherosclerotic Cardiovascular Disease: An Update.

    PubMed

    Cook, Nancy R; Ridker, Paul M

    2016-12-06

    The latest guidelines from the American College of Cardiology and American Heart Association, released in fall 2013, provide a long-anticipated update to the recommendations of the Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). The guidelines incorporate a new risk score for atherosclerotic cardiovascular disease that includes stroke as well as coronary heart disease. After publication, the new pooled cohort equations (PCEs) were evaluated in 15 studies from the United States and Europe, most of which used cohorts that were more contemporary than those used in developing the guidelines. In almost all of these external validation cohorts, the PCEs overestimated the observed risk. This narrative review provides an update of the published reports, an overview of the strengths and weaknesses of these validation efforts, and a discussion of possible reasons for the discrepancies. These issues may be useful in a recalibration process designed to better match predicted and observed risks relevant for current clinical practice.

  15. Anti-Atherosclerotic Actions of Azelaic acid, an End Product of Linoleic Acid Peroxidation, in Mice

    PubMed Central

    Litvinov, Dmitry; Selvarajan, Krithika; Garelnabi, Mahdi; Brophy, Larissa; Parthasarathy, Sampath

    2009-01-01

    Background Atherosclerosis is a chronic inflammatory disease associated with the accumulation of oxidized lipids in arterial lesions. Recently we studied the degradation of peroxidized linoleic acid and suggested that oxidation is an essential process that results in the generation of terminal products, namely mono- and dicarboxylic acids that may lack the pro-atherogenic effects of peroxidized lipids. In continuation of that study, we tested the effects of azelaic acid (AzA), one of the end products of linoleic acid peroxidation, on the development of atherosclerosis using low density lipoprotein receptor knockout (LDLr−/−) mice. Methods and results LDLr−/− mice were fed with a high fat and high cholesterol Western diet (WD group). Another group of animals were fed the same diet with AzA supplementation (WD+AzA group). After four months of feeding, mice were sacrificed and atherosclerotic lesions were measured. The results showed that the average lesion area in WD+AzA group was 38% (p<0.001) less as compared to WD group. The athero-protective effect of AzA was not related to changes in plasma lipid content. AzA supplementation decreased the level of CD68 macrophage marker by 34% (p<0.05). Conclusions The finding that AzA exhibits an anti-atherogenic effect suggests that oxidation of lipid peroxidation-derived aldehydes into carboxylic acids could be an important step in the body’s defense against oxidative damage. PMID:19880116

  16. A new murine model of stress-induced complex atherosclerotic lesions

    PubMed Central

    Najafi, Amir H.; Aghili, Nima; Tilan, Justin U.; Andrews, James A.; Peng, XinZhi; Lassance-Soares, Roberta M.; Sood, Subeena; Alderman, Lee O.; Abe, Ken; Li, Lijun; Kolodgie, Frank D.; Virmani, Renu; Zukowska, Zofia; Epstein, Stephen E.; Burnett, Mary Susan

    2013-01-01

    SUMMARY The primary purpose of this investigation was to determine whether ApoE−/− mice, when subjected to chronic stress, exhibit lesions characteristic of human vulnerable plaque and, if so, to determine the time course of such changes. We found that the lesions were remarkably similar to human vulnerable plaque, and that the time course of lesion progression raised interesting insights into the process of plaque development. Lard-fed mixed-background ApoE−/− mice exposed to chronic stress develop lesions with large necrotic core, thin fibrous cap and a high degree of inflammation. Neovascularization and intraplaque hemorrhage are observed in over 80% of stressed animals at 20 weeks of age. Previously described models report a prevalence of only 13% for neovascularization observed at a much later time point, between 36 and 60 weeks of age. Thus, our new stress-induced model of advanced atherosclerotic plaque provides an improvement over what is currently available. This model offers a tool to further investigate progression of plaque phenotype to a more vulnerable phenotype in humans. Our findings also suggest a possible use of this stress-induced model to determine whether therapeutic interventions have effects not only on plaque burden, but also, and importantly, on plaque vulnerability. PMID:23324329

  17. Human miR-221/222 in Physiological and Atherosclerotic Vascular Remodeling

    PubMed Central

    Chistiakov, Dmitry A.; Sobenin, Igor A.; Orekhov, Alexander N.; Bobryshev, Yuri V.

    2015-01-01

    A cluster of miR-221/222 is a key player in vascular biology through exhibiting its effects on vascular smooth muscle cells (VSMCs) and endothelial cells (ECs). These miRNAs contribute to vascular remodeling, an adaptive process involving phenotypic and behavioral changes in vascular cells in response to vascular injury. In proliferative vascular diseases such as atherosclerosis, pathological vascular remodeling plays a prominent role. The miR-221/222 cluster controls development and differentiation of ECs but inhibits their proangiogenic activation, proliferation, and migration. miR-221/222 are primarily implicated in maintaining endothelial integrity and supporting quiescent EC phenotype. Vascular expression of miR-221/222 is upregulated in initial atherogenic stages causing inhibition of angiogenic recruitment of ECs and increasing endothelial dysfunction and EC apoptosis. In contrast, these miRNAs stimulate VSMCs and switching from the VSMC “contractile” phenotype to the “synthetic” phenotype associated with induction of proliferation and motility. In atherosclerotic vessels, miR-221/222 drive neointima formation. Both miRNAs contribute to atherogenic calcification of VSMCs. In advanced plaques, chronic inflammation downregulates miR-221/222 expression in ECs that in turn could activate intralesion neoangiogenesis. In addition, both miRNAs could contribute to cardiovascular pathology through their effects on fat and glucose metabolism in nonvascular tissues such as adipose tissue, liver, and skeletal muscles. PMID:26221589

  18. An Experimental Fluid dynamics Study of Exact-Replica Atherosclerotic Carotid Bifurcations

    NASA Astrophysics Data System (ADS)

    Bale-Glickman, Jocelyn; Selby, Kathy; Saloner, David; Savas, Omer

    2003-11-01

    Physiological flow studies are carried out in two different models of atherosclerotic carotid bifurcations using flow visualization and particle image velocimetry (PIV). The flow models exactly replicate the lumen of plaques excised intact from patients with severe atherosclerosis. A boundary treatment technique is employed in PIV processing to estimate the flow strain rate near the wall, hence to estimate the wall shear stresses (WSS) to a first order accuracy. The systolic and diastolic Reynolds numbers are about 900 and 300, respectively, which match Doppler Ultrasound scans done on the patients just before surgery. The complex internal geometry of the diseased artery combined with the pulsatile input flows gives exceedingly complex flow patterns. The flows are highly three-dimensional and chaotic in which the details vary from cycle to cycle. The flow patterns include internal jets, three-dimensional shear layers, stagnation lines, separation zones and recirculation zones. The vorticity and streamline maps confirm the highly complex and three-dimensional nature of the flow. WSS are estimated to range from -7 Pa to 30 Pa at the stenotic neck over time. Companion experiments are also carried out with sinusoidal and steady CCA input flows for comparison.

  19. Optical detection of structural changes in human carotid atherosclerotic plaque

    NASA Astrophysics Data System (ADS)

    Korol, R. M.; Canham, P. B.; Finlay, H. M.; Hammond, R. R.; Quantz, M.; Ferguson, G. G.; Liu, L. Y.; Lucas, A. R.

    2005-08-01

    Background: Arterial bifurcations are commonly the sites of developing atherosclerotic plaque that lead to arterial occlusions and plaque rupture (myocardial infarctions and strokes). Laser induced fluorescence (LIF) spectroscopy provides an effective nondestructive method supplying spectral information on extracellular matrix (ECM) protein composition, specifically collagen and elastin. Purpose: To investigate regional differences in the ECM proteins -- collagen I, III and elastin in unstable plaque by analyzing data from laser-induced fluorescence spectroscopy of human carotid endarterectomy specimens. Methods: Gels of ECM protein extracts (elastin, collagen types I & III) were measured as reference spectra and internal thoracic artery segments (extra tissue from bypass surgery) were used as tissue controls. Arterial segments and the endarterectomy specimens (n=21) were cut into 5mm cross-sectional rings. Ten fluorescence spectra per sampling area were then recorded at 5 sites per ring with argon laser excitation (357nm) with a penetration depth of 200 μm. Spectra were normalized to maximum intensity and analyzed using multiple regression analysis. Tissue rings were fixed in formalin (within 3 hours of surgery), sectioned and stained with H&E or Movat's Pentachrome for histological analysis. Spectroscopy data were correlated with immunohistology (staining for elastin, collagen types I, III and IV). Results: Quantitative fluorescence for the thoracic arteries revealed a dominant elastin component on the luminal side -- confirmed with immunohistology and known artery structure. Carotid endarterectomy specimens by comparison had a significant decrease in elastin signature and increased collagen type I and III. Arterial spectra were markedly different between the thoracic and carotid specimens. There was also a significant elevation (p<0.05) of collagen type I distal to the bifurcation compared to proximal tissue in the carotid specimens. Conclusion: Fluorescence

  20. Global Overview of the Epidemiology of Atherosclerotic Cardiovascular Disease.

    PubMed

    Barquera, Simon; Pedroza-Tobías, Andrea; Medina, Catalina; Hernández-Barrera, Lucía; Bibbins-Domingo, Kirsten; Lozano, Rafael; Moran, Andrew E

    2015-07-01

    Atherosclerotic cardiovascular disease (ACD) is the leading cause of mortality worldwide. The objective of this paper is to provide an overview of the global burden of ACD and its risk factors and to discuss the main challenges and opportunities for prevention. Publicly available data from the Global Burden of Disease Study were analyzed for ischemic heart disease (IHD), ischemic stroke and ACD risk factors. Data from the WHO Global Health Observatory were used to describe prevalence of diverse cardiometabolic risk factors. World Bank Gross Domestic Product per capita (GDPc) information was used to categorize countries according to income level. Cardiovascular mortality decreased globally from 1990-2010 with important differences by GDPc; during 1990 there was a positive association between IHD mortality and GDPc. Higher-income countries had higher rates compared to those of lower-income countries. High levels of body mass index (BMI), blood pressure, glucose and cholesterol have a differential contribution to mortality by income group over time; high-income countries have been able to reduce the contribution from these risk factors in the last 20 years, whereas lower/middle income countries show an increasing trend in mortality attributable to high BMI and glucose. Although age-adjusted ACD mortality rate trends decreased globally, the absolute number of ACD deaths is increasing in part due to the growth of the population and aging, as well as to important lifestyle and food-system changes that likely attenuate gains in prevention. Population and individual level preventable causes of ACD must be aggressively and efficiently targeted in countries of lower economic development in order to reduce the growing burden of disease due to ACD.

  1. Atherosclerotic cardiovascular disease in patients with chronic inflammatory joint disorders.

    PubMed

    Agca, R; Heslinga, S C; van Halm, V P; Nurmohamed, M T

    2016-05-15

    Inflammatory joint disorders (IJD), including rheumatoid arthritis (RA), ankylosing spondylitis (ASp) and psoriatic arthritis (PsA), are prevalent conditions worldwide with a considerable burden on healthcare systems. IJD are associated with increased cardiovascular (CV) disease-related morbidity and mortality. In this review, we present an overview of the literature. Standardised mortality ratios are increased in IJD compared with the general population, that is, RA 1.3-2.3, ASp 1.6-1.9 and PsA 0.8-1.6. This premature mortality is mainly caused by atherosclerotic events. In RA, this CV risk is comparable to that in type 2 diabetes. Traditional CV risk factors are more often present and partially a consequence of changes in physical function related to the underlying IJD. Also, chronic systemic inflammation itself is an independent CV risk factor. Optimal control of disease activity with conventional synthetic, targeted synthetic and biological disease-modifying antirheumatic drugs decreases this excess risk. High-grade inflammation as well as anti-inflammatory treatment alter traditional CV risk factors, such as lipids. In view of the above-mentioned CV burden in patients with IJD, CV risk management is necessary. Presently, this CV risk management is still lacking in usual care. Patients, general practitioners, cardiologists, internists and rheumatologists need to be aware of the substantially increased CV risk in IJD and should make a combined effort to timely initiate CV risk management in accordance with prevailing guidelines together with optimal control of rheumatic disease activity. CV screening and treatment strategies need to be implemented in usual care.

  2. Graphics processing unit accelerated three-dimensional model for the simulation of pulsed low-temperature plasmas

    SciTech Connect

    Fierro, Andrew Dickens, James; Neuber, Andreas

    2014-12-15

    A 3-dimensional particle-in-cell/Monte Carlo collision simulation that is fully implemented on a graphics processing unit (GPU) is described and used to determine low-temperature plasma characteristics at high reduced electric field, E/n, in nitrogen gas. Details of implementation on the GPU using the NVIDIA Compute Unified Device Architecture framework are discussed with respect to efficient code execution. The software is capable of tracking around 10 × 10{sup 6} particles with dynamic weighting and a total mesh size larger than 10{sup 8} cells. Verification of the simulation is performed by comparing the electron energy distribution function and plasma transport parameters to known Boltzmann Equation (BE) solvers. Under the assumption of a uniform electric field and neglecting the build-up of positive ion space charge, the simulation agrees well with the BE solvers. The model is utilized to calculate plasma characteristics of a pulsed, parallel plate discharge. A photoionization model provides the simulation with additional electrons after the initial seeded electron density has drifted towards the anode. Comparison of the performance benefits between the GPU-implementation versus a CPU-implementation is considered, and a speed-up factor of 13 for a 3D relaxation Poisson solver is obtained. Furthermore, a factor 60 speed-up is realized for parallelization of the electron processes.

  3. Nontoxic chemical process for in situ permeability enhancement and accelerated decontamination of fine-grain subsurface sediments

    DOEpatents

    Kansa, Edward J.; Wijesinghe, Ananda M.; Viani, Brian E.

    1997-01-01

    The remediation of heterogeneous subsurfaces is extremely time consuming and expensive with current and developing technologies. Although such technologies can adequately remove contaminants in the high hydraulic conductivity, coarse-grained sediments, they cannot access the contaminated low hydraulic conductivity fine-grained sediments. The slow bleed of contaminants from the fine-grained sediments is the primary reason why subsurface remediation is so time-consuming and expensive. This invention addresses the problem of remediating contaminated fine-grained sediments. It is intended that, in the future, a heterogeneous site be treated by a hybrid process that first remediates the high hydraulic conductivity, coarse-grained sediments, to be followed by the process, described in this invention, to treat the contaminated low hydraulic conductivity fine-grained sediments. The invention uses cationic flocculents and organic solvents to collapse the swelling negative double layer surrounding water saturated clay particles, causing a flocculated, cracked clay structure. The modification of the clay fabric in fine-grained sediments dramatically increases the hydraulic conductivity of previously very tight clays many orders of magnitude.

  4. Nontoxic chemical process for in situ permeability enhancement and accelerated decontamination of fine-grain subsurface sediments

    DOEpatents

    Kansa, E.J.; Wijesinghe, A.M.; Viani, B.E.

    1997-01-14

    The remediation of heterogeneous subsurfaces is extremely time consuming and expensive with current and developing technologies. Although such technologies can adequately remove contaminants in the high hydraulic conductivity, coarse-grained sediments, they cannot access the contaminated low hydraulic conductivity fine-grained sediments. The slow bleed of contaminants from the fine-grained sediments is the primary reason why subsurface remediation is so time-consuming and expensive. This invention addresses the problem of remediating contaminated fine-grained sediments. It is intended that, in the future, a heterogeneous site be treated by a hybrid process that first remediates the high hydraulic conductivity, coarse-grained sediments, to be followed by the process, described in this invention, to treat the contaminated low hydraulic conductivity fine-grained sediments. The invention uses cationic flocculants and organic solvents to collapse the swelling negative double layer surrounding water saturated clay particles, causing a flocculated, cracked clay structure. The modification of the clay fabric in fine-grained sediments dramatically increases the hydraulic conductivity of previously very tight clays many orders of magnitude. 8 figs.

  5. Cast dielectric composite linear accelerator

    DOEpatents

    Sanders, David M.; Sampayan, Stephen; Slenes, Kirk; Stoller, H. M.

    2009-11-10

    A linear accelerator having cast dielectric composite layers integrally formed with conductor electrodes in a solventless fabrication process, with the cast dielectric composite preferably having a nanoparticle filler in an organic polymer such as a thermosetting resin. By incorporating this cast dielectric composite the dielectric constant of critical insulating layers of the transmission lines of the accelerator are increased while simultaneously maintaining high dielectric strengths for the accelerator.

  6. Multiscale investigation of USPIO nanoparticles in atherosclerotic plaques and their catabolism and storage in vivo.

    PubMed

    Maraloiu, Valentin-Adrian; Appaix, Florence; Broisat, Alexis; Le Guellec, Dominique; Teodorescu, Valentin Serban; Ghezzi, Catherine; van der Sanden, Boudewijn; Blanchin, Marie-Genevieve

    2016-01-01

    The storage and catabolism of Ultrasmall SuperParamagnetic Iron Oxide (USPIO) nanoparticles were analyzed through a multiscale approach combining Two Photon Laser Scanning Microscopy (TPLSM) and High-Resolution Transmission Electron Microscopy (HRTEM) at different times after intravenous injection in an atherosclerotic ApoE(-/-) mouse model. The atherosclerotic plaque features and the USPIO heterogeneous biodistribution were revealed down from organ's scale to subcellular level. The biotransformation of the nanoparticle iron oxide (maghemite) core into ferritin, the non-toxic form of iron storage, was demonstrated for the first time ex vivo in atherosclerotic plaques as well as in spleen, the iron storage organ. These results rely on an innovative spatial and structural investigation of USPIO's catabolism in cellular phagolysosomes. This study showed that these nanoparticles were stored as non-toxic iron compounds: maghemite oxide or ferritin, which is promising for MRI detection of atherosclerotic plaques in clinics using these USPIOs. From the Clinical Editor: Advance in nanotechnology has brought new contrast agents for clinical imaging. In this article, the authors investigated the use and biotransformation of Ultrasmall Super-paramagnetic Iron Oxide (USPIO) nanoparticles for analysis of atherosclerotic plagues in Two Photon Laser Scanning Microscopy (TPLSM) and High-Resolution Transmission Electron Microscopy (HRTEM). The biophysical data generated from this study could enable the possible use of these nanoparticles for the benefits of clinical patients.

  7. Leukocyte trafficking-associated vascular adhesion protein 1 is expressed and functionally active in atherosclerotic plaques

    PubMed Central

    Silvola, Johanna M. U.; Virtanen, Helena; Siitonen, Riikka; Hellberg, Sanna; Liljenbäck, Heidi; Metsälä, Olli; Ståhle, Mia; Saanijoki, Tiina; Käkelä, Meeri; Hakovirta, Harri; Ylä-Herttuala, Seppo; Saukko, Pekka; Jauhiainen, Matti; Veres, Tibor Z.; Jalkanen, Sirpa; Knuuti, Juhani; Saraste, Antti; Roivainen, Anne

    2016-01-01

    Given the important role of inflammation and the potential association of the leukocyte trafficking-associated adhesion molecule vascular adhesion protein 1 (VAP-1) with atherosclerosis, this study examined whether functional VAP-1 is expressed in atherosclerotic lesions and, if so, whether it could be targeted by positron emission tomography (PET). First, immunohistochemistry revealed that VAP-1 localized to endothelial cells of intra-plaque neovessels in human carotid endarterectomy samples from patients with recent ischemic symptoms. In low-density lipoprotein receptor-deficient mice expressing only apolipoprotein B100 (LDLR−/−ApoB100/100), VAP-1 was expressed on endothelial cells lining inflamed atherosclerotic lesions; normal vessel walls in aortas of C57BL/6N control mice were VAP-1-negative. Second, we discovered that the focal uptake of VAP-1 targeting sialic acid-binding immunoglobulin-like lectin 9 based PET tracer [68Ga]DOTA-Siglec-9 in atherosclerotic plaques was associated with the density of activated macrophages (r = 0.58, P = 0.022). As a final point, we found that the inhibition of VAP-1 activity with small molecule LJP1586 decreased the density of macrophages in inflamed atherosclerotic plaques in mice. Our results suggest for the first time VAP-1 as a potential imaging target for inflamed atherosclerotic plaques, and corroborate VAP-1 inhibition as a therapeutic approach in the treatment of atherosclerosis. PMID:27731409

  8. Particle Accelerators in China

    NASA Astrophysics Data System (ADS)

    Zhang, Chuang; Fang, Shouxian

    As the special machines that can accelerate charged particle beams to high energy by using electromagnetic fields, particle accelerators have been widely applied in scientific research and various areas of society. The development of particle accelerators in China started in the early 1950s. After a brief review of the history of accelerators, this article describes in the following sections: particle colliders, heavy-ion accelerators, high-intensity proton accelerators, accelerator-based light sources, pulsed power accelerators, small scale accelerators, accelerators for applications, accelerator technology development and advanced accelerator concepts. The prospects of particle accelerators in China are also presented.

  9. Accelerating Best Care in Pennsylvania: adapting a large academic system's quality improvement process to rural community hospitals.

    PubMed

    Haydar, Ziad; Gunderson, Julie; Ballard, David J; Skoufalos, Alexis; Berman, Bettina; Nash, David B

    2008-01-01

    Industrial quality improvement (QI) methods such as continuous quality improvement (CQI) may help bridge the gap between evidence-based "best care" and the quality of care provided. In 2006, Baylor Health Care System collaborated with Jefferson Medical College of Thomas Jefferson University to conduct a QI demonstration project in select Pennsylvania hospitals using CQI techniques developed by Baylor. The training was provided over a 6-month period and focused on methods for rapid-cycle improvement; data system design; data management; tools to improve patient outcomes, processes of care, and cost-effectiveness; use of clinical guidelines and protocols; leadership skills; and customer service skills. Participants successfully implemented a variety of QI projects. QI education programs developed and pioneered within large health care systems can be adapted and applied successfully to other settings, providing needed tools to smaller rural and community hospitals that lack the necessary resources to establish such programs independently.

  10. Compact accelerator

    DOEpatents

    Caporaso, George J.; Sampayan, Stephen E.; Kirbie, Hugh C.

    2007-02-06

    A compact linear accelerator having at least one strip-shaped Blumlein module which guides a propagating wavefront between first and second ends and controls the output pulse at the second end. Each Blumlein module has first, second, and third planar conductor strips, with a first dielectric strip between the first and second conductor strips, and a second dielectric strip between the second and third conductor strips. Additionally, the compact linear accelerator includes a high voltage power supply connected to charge the second conductor strip to a high potential, and a switch for switching the high potential in the second conductor strip to at least one of the first and third conductor strips so as to initiate a propagating reverse polarity wavefront(s) in the corresponding dielectric strip(s).

  11. FPGA Verification Accelerator (FVAX)

    NASA Technical Reports Server (NTRS)

    Oh, Jane; Burke, Gary

    2008-01-01

    Is Verification Acceleration Possible? - Increasing the visibility of the internal nodes of the FPGA results in much faster debug time - Forcing internal signals directly allows a problem condition to be setup very quickly center dot Is this all? - No, this is part of a comprehensive effort to improve the JPL FPGA design and V&V process.

  12. BICEP's acceleration

    SciTech Connect

    Contaldi, Carlo R.

    2014-10-01

    The recent Bicep2 [1] detection of, what is claimed to be primordial B-modes, opens up the possibility of constraining not only the energy scale of inflation but also the detailed acceleration history that occurred during inflation. In turn this can be used to determine the shape of the inflaton potential V(φ) for the first time — if a single, scalar inflaton is assumed to be driving the acceleration. We carry out a Monte Carlo exploration of inflationary trajectories given the current data. Using this method we obtain a posterior distribution of possible acceleration profiles ε(N) as a function of e-fold N and derived posterior distributions of the primordial power spectrum P(k) and potential V(φ). We find that the Bicep2 result, in combination with Planck measurements of total intensity Cosmic Microwave Background (CMB) anisotropies, induces a significant feature in the scalar primordial spectrum at scales k∼ 10{sup -3} Mpc {sup -1}. This is in agreement with a previous detection of a suppression in the scalar power [2].

  13. PKCβ Promotes Vascular inflammation and Acceleration of Atherosclerosis in Diabetic ApoE Null Mice

    PubMed Central

    Kong, Linghua; Shen, Xiaoping; Lin, Lili; Leitges, Michael; Rosario, Rosa; Zou, Yu Shan; Yan, Shi Fang

    2013-01-01

    Objective Diabetic subjects are at high risk for developing atherosclerosis through a variety of mechanisms. As the metabolism of glucose results in production of activators of protein kinase C (PKC)β, it was logical to investigate the role of PKCβ in modulation of atherosclerosis in diabetes. Approach and Results ApoE−/− and PKCβ −/−/ApoE−/− mice were rendered diabetic with streptozotocin. Quantification of atherosclerosis, gene expression profiling or analysis of signaling molecules was performed on aortic sinus or aortas from diabetic mice. Diabetes-accelerated atherosclerosis increased the level of phosphorylated ERK1/2 and JNK mitogen activated protein (MAP) kinases and augmented vascular expression of inflammatory mediators, as well as increased monocyte/macrophage infiltration and CD11c+ cells accumulation in diabetic ApoE−/− mice; processes which were diminished in diabetic PKCβ −/−/ApoE−/− mice. In addition, pharmacological inhibition of PKCβ reduced atherosclerotic lesion size in diabetic ApoE−/− mice. In vitro, the inhibitors of PKCβ and ERK1/2, as well as small interfering RNA (siRNA) to Egr-1 significantly decreased high glucose-induced expression of CD11c (Itgax), chemokine (C-C motif) ligand 2 (CCL2) and interleukin (IL)-1β in U937 macrophages. Conclusions These data link enhanced activation of PKCβ to accelerated diabetic atherosclerosis via a mechanism that includes modulation of gene transcription and signal transduction in the vascular wall; processes that contribute to acceleration of vascular inflammation and atherosclerosis in diabetes. Our results uncover a novel role for PKCβ in modulating CD11c expression and inflammatory response of macrophages in the development of diabetic atherosclerosis. These findings support PKCβ activation as a potential therapeutic target for prevention and treatment of diabetic atherosclerosis. PMID:23766264

  14. A Doping Lattice of Aluminum and Copper with Accelerated Electron Transfer Process and Enhanced Reductive Degradation Performance

    NASA Astrophysics Data System (ADS)

    Zhang, Lin; Gao, Xue; Zhang, Zhixuan; Zhang, Mingbo; Cheng, Yiqian; Su, Jixin

    2016-08-01

    Treatment of azo dye effluents has received increasing concerns over the years due to their potential harms to natural environment and human health. The present study described the degrading ability of the as-synthesized crystalline Al-Cu alloys for removal of high-concentration Acid Scarlet 3R in alkaline aqueous solutions and its degradation mechanism. Al-Cu alloy particles with Al/Cu ratios 19:1 were successfully synthesized by high-energy mechanical milling. Characterization results showed that 10 h mechanical alloying process could lead to the formation of crystalline Al(Cu) solid solution. Batch experiment results confirmed the excellent ability of Al-Cu alloy particles for the degradation of 3R in aqueous solution. Under a certain condition ([Al-Cu]0 = 2 g/L, [3R]0 = 200 mg/L, [NaCl]0 = 25 g/L, initial pH = 10.9), the 3R could be completely degraded within only 3 min. It was also found that the degradation reaction followed zero-order kinetics model with respect to the initial dye concentration. The intermediate compounds were identified by UV-vis, FT-IR and HPLC-MS, and a pathway was proposed. Additionally, post-treatment Al-Cu alloy particles were characterized by SEM and TEM, and the results showed that the degradation might be attributed to the corrosion effect of Al-Cu alloys.

  15. A Doping Lattice of Aluminum and Copper with Accelerated Electron Transfer Process and Enhanced Reductive Degradation Performance

    PubMed Central

    Zhang, Lin; Gao, Xue; Zhang, Zhixuan; Zhang, Mingbo; Cheng, Yiqian; Su, Jixin

    2016-01-01

    Treatment of azo dye effluents has received increasing concerns over the years due to their potential harms to natural environment and human health. The present study described the degrading ability of the as-synthesized crystalline Al-Cu alloys for removal of high-concentration Acid Scarlet 3R in alkaline aqueous solutions and its degradation mechanism. Al-Cu alloy particles with Al/Cu ratios 19:1 were successfully synthesized by high-energy mechanical milling. Characterization results showed that 10 h mechanical alloying process could lead to the formation of crystalline Al(Cu) solid solution. Batch experiment results confirmed the excellent ability of Al-Cu alloy particles for the degradation of 3R in aqueous solution. Under a certain condition ([Al-Cu]0 = 2 g/L, [3R]0 = 200 mg/L, [NaCl]0 = 25 g/L, initial pH = 10.9), the 3R could be completely degraded within only 3 min. It was also found that the degradation reaction followed zero-order kinetics model with respect to the initial dye concentration. The intermediate compounds were identified by UV-vis, FT-IR and HPLC-MS, and a pathway was proposed. Additionally, post-treatment Al-Cu alloy particles were characterized by SEM and TEM, and the results showed that the degradation might be attributed to the corrosion effect of Al-Cu alloys. PMID:27535800

  16. A Doping Lattice of Aluminum and Copper with Accelerated Electron Transfer Process and Enhanced Reductive Degradation Performance.

    PubMed

    Zhang, Lin; Gao, Xue; Zhang, Zhixuan; Zhang, Mingbo; Cheng, Yiqian; Su, Jixin

    2016-08-18

    Treatment of azo dye effluents has received increasing concerns over the years due to their potential harms to natural environment and human health. The present study described the degrading ability of the as-synthesized crystalline Al-Cu alloys for removal of high-concentration Acid Scarlet 3R in alkaline aqueous solutions and its degradation mechanism. Al-Cu alloy particles with Al/Cu ratios 19:1 were successfully synthesized by high-energy mechanical milling. Characterization results showed that 10 h mechanical alloying process could lead to the formation of crystalline Al(Cu) solid solution. Batch experiment results confirmed the excellent ability of Al-Cu alloy particles for the degradation of 3R in aqueous solution. Under a certain condition ([Al-Cu]0 = 2 g/L, [3R]0 = 200 mg/L, [NaCl]0 = 25 g/L, initial pH = 10.9), the 3R could be completely degraded within only 3 min. It was also found that the degradation reaction followed zero-order kinetics model with respect to the initial dye concentration. The intermediate compounds were identified by UV-vis, FT-IR and HPLC-MS, and a pathway was proposed. Additionally, post-treatment Al-Cu alloy particles were characterized by SEM and TEM, and the results showed that the degradation might be attributed to the corrosion effect of Al-Cu alloys.

  17. New methods for optical distance indicator and gantry angle quality control tests in medical linear accelerators: image processing by using a 3D phantom

    PubMed Central

    Shandiz, Mahdi Heravian; Anvari, Kazem; Khalilzadeh, Mohammadmahdi

    2015-01-01

    Purpose In order to keep the acceptable level of the radiation oncology linear accelerators, it is necessary to apply a reliable quality assurance (QA) program. Materials and Methods The QA protocols, published by authoritative organizations, such as the American Association of Physicists in Medicine (AAPM), determine the quality control (QC) tests which should be performed on the medical linear accelerators and the threshold levels for each test. The purpose of this study is to increase the accuracy and precision of the selected QC tests in order to increase the quality of treatment and also increase the speed of the tests to convince the crowded centers to start a reliable QA program. A new method has been developed for two of the QC tests; optical distance indicator (ODI) QC test as a daily test and gantry angle QC test as a monthly test. This method uses an image processing approach utilizing the snapshots taken by the CCD camera to measure the source to surface distance (SSD) and gantry angle. Results The new method of ODI QC test has an accuracy of 99.95% with a standard deviation of 0.061 cm and the new method for gantry angle QC has a precision of 0.43°. The automated proposed method which is used for both ODI and gantry angle QC tests, contains highly accurate and precise results which are objective and the human-caused errors have no effect on the results. Conclusion The results show that they are in the acceptable range for both of the QC tests, according to AAPM task group 142. PMID:25874177

  18. Chronic miR-29 antagonism promotes favorable plaque remodeling in atherosclerotic mice.

    PubMed

    Ulrich, Victoria; Rotllan, Noemi; Araldi, Elisa; Luciano, Amelia; Skroblin, Philipp; Abonnenc, Mélanie; Perrotta, Paola; Yin, Xiaoke; Bauer, Ashley; Leslie, Kristen L; Zhang, Pei; Aryal, Binod; Montgomery, Rusty L; Thum, Thomas; Martin, Kathleen; Suarez, Yajaira; Mayr, Manuel; Fernandez-Hernando, Carlos; Sessa, William C

    2016-06-01

    Abnormal remodeling of atherosclerotic plaques can lead to rupture, acute myocardial infarction, and death. Enhancement of plaque extracellular matrix (ECM) may improve plaque morphology and stabilize lesions. Here, we demonstrate that chronic administration of LNA-miR-29 into an atherosclerotic mouse model improves indices of plaque morphology. This occurs due to upregulation of miR-29 target genes of the ECM (col1A and col3A) resulting in reduced lesion size, enhanced fibrous cap thickness, and reduced necrotic zones. Sustained LNA-miR-29 treatment did not affect circulating lipids, blood chemistry, or ECM of solid organs including liver, lung, kidney, spleen, or heart. Collectively, these data support the idea that antagonizing miR-29 may promote beneficial plaque remodeling as an independent approach to stabilize vulnerable atherosclerotic lesions.

  19. MR histology of advanced atherosclerotic lesions of ApoE- knockout mice

    NASA Astrophysics Data System (ADS)

    Naumova, A.; Yarnykh, V.; Ferguson, M.; Rosenfeld, M.; Yuan, C.

    2016-02-01

    The purposes of this study were to examine the feasibility of determining the composition of advanced atherosclerotic plaques in fixed ApoE-knockout mice and to develop a time-efficient microimaging protocol for MR histological imaging on mice. Five formalin-fixed transgenic ApoE-knockout mice were imaged at the 9.4T Bruker BioSpec MR scanner using 3D spoiled gradient-echo sequence with an isotropic field of view of 24 mm3; TR 20.8 ms; TE 2.6 ms; flip angle 20°, resulted voxel size 47 × 63 × 94 pm3. MRI examination has shown that advanced atherosclerotic lesions of aorta, innominate and carotid arteries in ApoE-knockout mice are characterized by high calcification and presence of the large fibrofatty nodules. MRI quantification of atherosclerotic lesion components corresponded to histological assessment of plaque composition with a correlation coefficient of 0.98.

  20. Genesis and growth of extracellular vesicle-derived microcalcification in atherosclerotic plaques

    PubMed Central

    Hutcheson, Joshua D.; Goettsch, Claudia; Bertazzo, Sergio; Maldonado, Natalia; Ruiz, Jessica L.; Goh, Wilson; Yabusaki, Katsumi; Faits, Tyler; Bouten, Carlijn; Franck, Gregory; Quillard, Thibaut; Libby, Peter; Aikawa, Masanori; Weinbaum, Sheldon; Aikawa, Elena

    2015-01-01

    Clinical evidence links arterial calcification and cardiovascular risk. Finite-element modelling of the stress distribution within atherosclerotic plaques has suggested that subcellular microcalcifications in the fibrous cap may promote material failure of the plaque, but that large calcifications can stabilize it. Yet the physicochemical mechanisms underlying such mineral formation and growth in atheromata remain unknown. Here, by using three-dimensional collagen hydrogels that mimic structural features of the atherosclerotic fibrous cap, and high-resolution microscopic and spectroscopic analyses of both the hydrogels and of calcified human plaques, we demonstrate that calcific mineral formation and maturation results from a series of events involving the aggregation of calcifying extracellular vesicles, and the formation of microcalcifications and ultimately large calcification zones. We also show that calcification morphology and the plaque’s collagen content – two determinants of atherosclerotic plaque stability - are interlinked. PMID:26752654

  1. Vulnerable atherosclerotic carotid plaque evaluation by ultrasound, computed tomography angiography, and magnetic resonance imaging: an overview.

    PubMed

    Naim, Cyrille; Douziech, Maxime; Therasse, Eric; Robillard, Pierre; Giroux, Marie-France; Arsenault, Frederic; Cloutier, Guy; Soulez, Gilles

    2014-08-01

    Ischemic syndromes associated with carotid atherosclerotic disease are often related to plaque rupture. The benefit of endarterectomy for high-grade carotid stenosis in symptomatic patients has been established. However, in asymptomatic patients, the benefit of endarterectomy remains equivocal. Current research seeks to risk stratify asymptomatic patients by characterizing vulnerable, rupture-prone atherosclerotic plaques. Plaque composition, biology, and biomechanics are studied by noninvasive imaging techniques such as magnetic resonance imaging, computed tomography, ultrasound, and ultrasound elastography. These techniques are at a developmental stage and have yet to be used in clinical practice. This review will describe noninvasive techniques in ultrasound, magnetic resonance imaging, and computed tomography imaging modalities used to characterize atherosclerotic plaque, and will discuss their potential clinical applications, benefits, and drawbacks.

  2. Genesis and growth of extracellular-vesicle-derived microcalcification in atherosclerotic plaques

    NASA Astrophysics Data System (ADS)

    Hutcheson, Joshua D.; Goettsch, Claudia; Bertazzo, Sergio; Maldonado, Natalia; Ruiz, Jessica L.; Goh, Wilson; Yabusaki, Katsumi; Faits, Tyler; Bouten, Carlijn; Franck, Gregory; Quillard, Thibaut; Libby, Peter; Aikawa, Masanori; Weinbaum, Sheldon; Aikawa, Elena

    2016-03-01

    Clinical evidence links arterial calcification and cardiovascular risk. Finite-element modelling of the stress distribution within atherosclerotic plaques has suggested that subcellular microcalcifications in the fibrous cap may promote material failure of the plaque, but that large calcifications can stabilize it. Yet the physicochemical mechanisms underlying such mineral formation and growth in atheromata remain unknown. Here, by using three-dimensional collagen hydrogels that mimic structural features of the atherosclerotic fibrous cap, and high-resolution microscopic and spectroscopic analyses of both the hydrogels and of calcified human plaques, we demonstrate that calcific mineral formation and maturation results from a series of events involving the aggregation of calcifying extracellular vesicles, and the formation of microcalcifications and ultimately large calcification areas. We also show that calcification morphology and the plaque’s collagen content--two determinants of atherosclerotic plaque stability--are interlinked.

  3. [The effect of carotid endarterectomy on cognitive disturbances in patients with atherosclerotic stenosis of carotid arteries].

    PubMed

    Iakhno, N N; Fedorova, T S; Damulin, I V; Shcherbiuk, A N; Vinogradov, O A; Lavrent'ev, A V

    2011-01-01

    Clinical and neuropsychological features of non-dementia cognitive disturbances were studied in 102 patients with atherosclerotic carotid stenosis. Cognitive disturbances were assessed after the carotid endarterectomy (CEAE). Mild cognitive impairment was found in 37 (36,3%) of patients, moderate cognitive impairment was diagnosed in 36 (35,3%)patients. Moderate cognitive impairment was found more often in patients with symptomatic carotid stenosis with structural brain changes confirmed by neuroimaging data and with instable atherosclerotic plaques with the predomination of hypodensity component. It allows to suggest that both the reduction of perfusion and arterio-arterial microemboli may cause cognitive dysfunction in patients with atherosclerotic carotid stenosis. The data on the positive effect of CEAE on cognitive functions have been obtained. The positive changes were more distinct in patients with asymptomatic course of carotid stenosis. However CEAE may have a negative effect on cognitive functions in patients with moderate cognitive impairment of dysmnestic character and symptomatic carotid stenosis.

  4. Accelerators for research and applications

    SciTech Connect

    Alonso, J.R.

    1990-06-01

    The newest particle accelerators are almost always built for extending the frontiers of research, at the cutting edge of science and technology. Once these machines are operating and these technologies mature, new applications are always found, many of which touch our lives in profound ways. The evolution of accelerator technologies will be discussed, with descriptions of accelerator types and characteristics. The wide range of applications of accelerators will be discussed, in fields such as nuclear science, medicine, astrophysics and space-sciences, power generation, airport security, materials processing and microcircuit fabrication. 13 figs.

  5. Advanced concepts for acceleration

    SciTech Connect

    Keefe, D.

    1986-07-01

    Selected examples of advanced accelerator concepts are reviewed. Such plasma accelerators as plasma beat wave accelerator, plasma wake field accelerator, and plasma grating accelerator are discussed particularly as examples of concepts for accelerating relativistic electrons or positrons. Also covered are the pulsed electron-beam, pulsed laser accelerator, inverse Cherenkov accelerator, inverse free-electron laser, switched radial-line accelerators, and two-beam accelerator. Advanced concepts for ion acceleration discussed include the electron ring accelerator, excitation of waves on intense electron beams, and two-wave combinations. (LEW)

  6. Bacterial Communities Associated with Atherosclerotic Plaques from Russian Individuals with Atherosclerosis

    PubMed Central

    Ziganshina, Elvira E.; Sharifullina, Dilyara M.; Lozhkin, Andrey P.; Khayrullin, Rustem N.; Ignatyev, Igor M.; Ziganshin, Ayrat M.

    2016-01-01

    Atherosclerosis is considered a chronic disease of the arterial wall and is the major cause of severe disease and death among individuals all over the world. Some recent studies have established the presence of bacteria in atherosclerotic plaque samples and suggested their possible contribution to the development of cardiovascular disease. The main objective of this preliminary pilot study was to better understand the bacterial diversity and abundance in human atherosclerotic plaques derived from common carotid arteries of individuals with atherosclerosis (Russian nationwide group) and contribute towards the further identification of a main group of atherosclerotic plaque bacteria by 454 pyrosequencing their 16S ribosomal RNA (16S rRNA) genes. The applied approach enabled the detection of bacterial DNA in all atherosclerotic plaques. We found that distinct members of the order Burkholderiales were present at high levels in all atherosclerotic plaques obtained from patients with atherosclerosis with the genus Curvibacter being predominant in all plaque samples. Moreover, unclassified Burkholderiales as well as members of the genera Propionibacterium and Ralstonia were typically the most significant taxa for all atherosclerotic plaques. Other genera such as Burkholderia, Corynebacterium and Sediminibacterium as well as unclassified Comamonadaceae, Oxalobacteraceae, Rhodospirillaceae, Bradyrhizobiaceae and Burkholderiaceae were always found but at low relative abundances of the total 16S rRNA gene population derived from all samples. Also, we found that some bacteria found in plaque samples correlated with some clinical parameters, including total cholesterol, alanine aminotransferase and fibrinogen levels. Finally, our study indicates that some bacterial agents at least partially may be involved in affecting the development of cardiovascular disease through different mechanisms. PMID:27736997

  7. Bacterial Communities Associated with Atherosclerotic Plaques from Russian Individuals with Atherosclerosis.

    PubMed

    Ziganshina, Elvira E; Sharifullina, Dilyara M; Lozhkin, Andrey P; Khayrullin, Rustem N; Ignatyev, Igor M; Ziganshin, Ayrat M

    2016-01-01

    Atherosclerosis is considered a chronic disease of the arterial wall and is the major cause of severe disease and death among individuals all over the world. Some recent studies have established the presence of bacteria in atherosclerotic plaque samples and suggested their possible contribution to the development of cardiovascular disease. The main objective of this preliminary pilot study was to better understand the bacterial diversity and abundance in human atherosclerotic plaques derived from common carotid arteries of individuals with atherosclerosis (Russian nationwide group) and contribute towards the further identification of a main group of atherosclerotic plaque bacteria by 454 pyrosequencing their 16S ribosomal RNA (16S rRNA) genes. The applied approach enabled the detection of bacterial DNA in all atherosclerotic plaques. We found that distinct members of the order Burkholderiales were present at high levels in all atherosclerotic plaques obtained from patients with atherosclerosis with the genus Curvibacter being predominant in all plaque samples. Moreover, unclassified Burkholderiales as well as members of the genera Propionibacterium and Ralstonia were typically the most significant taxa for all atherosclerotic plaques. Other genera such as Burkholderia, Corynebacterium and Sediminibacterium as well as unclassified Comamonadaceae, Oxalobacteraceae, Rhodospirillaceae, Bradyrhizobiaceae and Burkholderiaceae were always found but at low relative abundances of the total 16S rRNA gene population derived from all samples. Also, we found that some bacteria found in plaque samples correlated with some clinical parameters, including total cholesterol, alanine aminotransferase and fibrinogen levels. Finally, our study indicates that some bacterial agents at least partially may be involved in affecting the development of cardiovascular disease through different mechanisms.

  8. Mapping elasticity moduli of atherosclerotic plaque in situ via atomic force microscopy.

    PubMed

    Tracqui, Philippe; Broisat, Alexis; Toczek, Jackub; Mesnier, Nicolas; Ohayon, Jacques; Riou, Laurent

    2011-04-01

    Several studies have suggested that evolving mechanical stresses and strains drive atherosclerotic plaque development and vulnerability. Especially, stress distribution in the plaque fibrous capsule is an important determinant for the risk of vulnerable plaque rupture. Knowledge of the stiffness of atherosclerotic plaque components is therefore of critical importance. In this work, force mapping experiments using atomic force microscopy (AFM) were conducted in apolipoprotein E-deficient (ApoE(-/-)) mouse, which represents the most widely used experimental model for studying mechanisms underlying the development of atherosclerotic lesions. To obtain the elastic material properties of fibrous caps and lipidic cores of atherosclerotic plaques, serial cross-sections of aortic arch lesions were probed at different sites. Atherosclerotic plaque sub-structures were subdivided into cellular fibrotic, hypocellular fibrotic and lipidic rich areas according to histological staining. Hertz's contact mechanics were used to determine elasticity (Young's) moduli that were related to the underlying histological plaque structure. Cellular fibrotic regions exhibit a mean Young modulus of 10.4±5.7kPa. Hypocellular fibrous caps were almost six-times stiffer, with average modulus value of 59.4±47.4kPa, locally rising up to ∼250kPa. Lipid rich areas exhibit a rather large range of Young's moduli, with average value of 5.5±3.5kPa. Such precise quantification of plaque stiffness heterogeneity will allow investigators to have prospectively a better monitoring of atherosclerotic disease evolution, including arterial wall remodeling and plaque rupture, in response to mechanical constraints imposed by vascular shear stress and blood pressure.

  9. Laser acceleration and its future

    PubMed Central

    Tajima, Toshiki

    2010-01-01

    Laser acceleration is based on the concept to marshal collective fields that may be induced by laser. In order to exceed the material breakdown field by a large factor, we employ the broken-down matter of plasma. While the generated wakefields resemble with the fields in conventional accelerators in their structure (at least qualitatively), it is their extreme accelerating fields that distinguish the laser wakefield from others, amounting to tiny emittance and compact accelerator. The current research largely falls on how to master the control of acceleration process in spatial and temporal scales several orders of magnitude smaller than the conventional method. The efforts over the last several years have come to a fruition of generating good beam properties with GeV energies on a table top, leading to many applications, such as ultrafast radiolysis, intraoperative radiation therapy, injection to X-ray free electron laser, and a candidate for future high energy accelerators. PMID:20228616

  10. Advanced accelerator theory development

    SciTech Connect

    Sampayan, S.E.; Houck, T.L.; Poole, B.; Tishchenko, N.; Vitello, P.A.; Wang, I.

    1998-02-09

    A new accelerator technology, the dielectric wall accelerator (DWA), is potentially an ultra compact accelerator/pulsed power driver. This new accelerator relies on three new components: the ultra-high gradient insulator, the asymmetric Blumlein and low jitter switches. In this report, we focused our attention on the first two components of the DWA system the insulators and the asymmetric Blumlein. First, we sought to develop the necessary design tools to model and scale the behavior of the high gradient insulator. To perform this task we concentrated on modeling the discharge processes (i.e., initiation and creation of the surface discharge). In addition, because these high gradient structures exhibit favorable microwave properties in certain accelerator configurations, we performed experiments and calculations to determine the relevant electromagnetic properties. Second, we performed circuit modeling to understand energy coupling to dynamic loads by the asymmetric Blumlein. Further, we have experimentally observed a non-linear coupling effect in certain asymmetric Blumlein configurations. That is, as these structures are stacked into a complete module, the output voltage does not sum linearly and a lower than expected output voltage results. Although we solved this effect experimentally, we performed calculations to understand this effect more fully to allow better optimization of this DWA pulse-forming line system.

  11. Prevalence and risk factors for atherosclerotic carotid stenosis and plaque

    PubMed Central

    Woo, Shin Young; Joh, Jin Hyun; Han, Sang-Ah; Park, Ho-Chul

    2017-01-01

    Abstract Atherosclerotic carotid stenosis (ACS) is a major cause of ischemic stroke. Screening for asymptomatic ACS is important to identify the patients who require longitudinal surveillance, medication, or endovascular surgery. The aim of this study was to assess the prevalence and risk factors for ACS and carotid plaque (CP) in Korea using a population-based screening study. We recruited participants during visits to several community welfare centers in Korea. The baseline characteristics of the study population were collected. All patients underwent duplex ultrasonography to examine their bilateral carotid arteries. ACS was defined as the presence of plaque with ≥50% vessel diameter reduction and peak systolic velocity (PSV) ≥125 cm/s or PSV ratio ≥2.0. CP was defined as the presence of plaque with <50% vessel diameter reduction. The Mann–Whitney test, χ2 test, Fisher exact test, and logistic regression were used in the statistical analysis. A total of 3030 participants were enrolled in this study (male 43.7% and female 56.3%). The prevalence of ACS and CP was 1.1% and 5.7%, respectively. Significant risk factors for CP included age ≥80 years (odds ratio [OR], 8.11; 95% confidence interval [CI], 3.45–18.93), male sex (OR, 2.16; 95% CI, 1.29–3.61), hypertension (OR, 1.72; 95% CI, 1.21–2.45), and hyperlipidemia (OR, 1.84; 95% CI, 1.30–2.62). The presence of ACS was significantly associated with age (OR, 1.07; 95% CI, 1.03–1.12), hypertension (OR, 3.16; 95% CI, 1.34–7.46), and being an ex-smoker (OR, 6.81; 95% CI, 1.66–27.93) or current smoker (OR, 6.97; 95% CI, 1.78–27.31) after adjusting for confounding factors. This population-based screening study revealed that ACS was uncommon and had a prevalence of 1.1% in the study population. Age, hypertension, and smoking were risk factors for ACS. Further investigations into the prevalence and risk factors of ACS are required, as are studies on the cost-effectiveness of a national screening

  12. A case of atherosclerotic inferior mesenteric artery aneurysm secondary to high flow state.

    PubMed

    Troisi, Nicola; Esposito, Giovanni; Cefalì, Pietro; Setti, Marco

    2011-07-01

    Inferior mesenteric artery aneurysms are very rare and they are among the rarest of visceral artery aneurysms. Sometimes, the distribution of the blood flow due to chronic atherosclerotic occlusion of some arteries can establish an increased flow into a particular supplying district (high flow state). A high flow state in a stenotic inferior mesenteric artery in compensation for a mesenteric occlusive disease can produce a rare form of aneurysm. We report the case of an atherosclerotic inferior mesenteric aneurysm secondary to high flow state (association with occlusion of the celiac trunk and severe stenosis of the superior mesenteric artery), treated by open surgical approach.

  13. Specific imaging of atherosclerotic plaque lipids with two-wavelength intravascular photoacoustics

    PubMed Central

    Wu, Min; Jansen, Krista; van der Steen, Antonius F. W.; van Soest, Gijs

    2015-01-01

    The lipid content in plaques is an important marker for identifying atherosclerotic lesions and disease states. Intravascular photoacoustic (IVPA) imaging can be used to visualize lipids in the artery. In this study, we further investigated lipid detection in the 1.7-µm spectral range. By exploiting the relative difference between the IVPA signal strengths at 1718 and 1734 nm, we could successfully detect and differentiate between the plaque lipids and peri-adventitial fat in human coronary arteries ex vivo. Our study demonstrates that IVPA imaging can positively identify atherosclerotic plaques using only two wavelengths, which could enable rapid data acquisition in vivo. PMID:26417500

  14. Immunostaining of macrophages, endothelial cells and smooth muscle cells in the atherosclerotic mouse aorta

    PubMed Central

    Menon, Prashanthi; Fisher, Edward A.

    2016-01-01

    The atherosclerotic mouse aorta consists of a heterogeneous population of cells, including macrophages, endothelial cells (EC) and smooth muscle cells (SMC), that play critical roles in cardiovascular disease. Identification of these vascular cells in the vessel wall is important to understanding their function in pathological conditions. Immunohistochemistry is an invaluable technique used to detect the presence of cells in different tissues. Here, we describe immunohistochemical techniques commonly used for the detection of the vascular cells in the atherosclerotic mouse aorta using cell specific markers. PMID:26445786

  15. Renovascular heart failure: heart failure in patients with atherosclerotic renal artery disease.

    PubMed

    Kawarada, Osami; Yasuda, Satoshi; Noguchi, Teruo; Anzai, Toshihisa; Ogawa, Hisao

    2016-07-01

    Atherosclerotic renal artery disease presents with a broad spectrum of clinical features, including heart failure as well as hypertension, and renal failure. Although recent randomized controlled trials failed to demonstrate renal artery stenting can reduce blood pressure or the number of cardiovascular or renal events more so than medical therapy, increasing attention has been paid to flash pulmonary edema and congestive heart failure associated with atherosclerotic renal artery disease. This clinical entity "renovascular heart failure" is diagnosed retrospectively. Given the increasing global burden of heart failure, this review highlights the background and catheter-based therapeutic aspects for renovascular heart failure.

  16. Characterization of atherosclerotic plaques by cross-polarization optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Gubarkova, Ekaterina V.; Dudenkova, Varvara V.; Feldchtein, Felix I.; Timofeeva, Lidia B.; Kiseleva, Elena B.; Kuznetsov, Sergei S.; Moiseev, Alexander A.; Gelikonov, Gregory V.; Vitkin, Alex I.; Gladkova, Natalia D.

    2016-02-01

    We combined cross-polarization optical coherence tomography (CP OCT) and non-linear microscopy based on second harmonic generation (SHG) and two-photon-excited fluorescence (2PEF) to assess collagen and elastin fibers in the development of the atherosclerotic plaque (AP). The study shows potential of CP OCT for the assessment of collagen and elastin fibers condition in atherosclerotic arteries. Specifically, the additional information afforded by CP OCT, related to birefringence and cross-scattering properties of arterial tissues, may improve the robustness and accuracy of assessment about the microstructure and composition of the plaque for different stages of atherosclerosis.

  17. Chimney stent technique for treatment of severe abdominal aortic atherosclerotic stenosis.

    PubMed

    Ritter, Jens C; Ghosh, Jonathan; Butterfield, John S; McCollum, Charles N; Ashleigh, Raymond

    2011-03-01

    Application of the "chimney" stent technique is described in a case of complex multilevel atherosclerotic disease involving the juxtarenal aorta. A patient with significant comorbidities was unsuitable for major open reconstructive surgery. He was treated with a combined procedure consisting of chimney stent placement in the juxtarenal aorta, iliac "kissing" stent placement, and right-sided common femoral artery (CFA) replacement. This case shows that the chimney stent technique can be a feasible alternative to leaving a safety wire in the renal arteries and observation during primary angioplasty in complex atherosclerotic lesions of the abdominal aorta.

  18. Impact accelerations

    NASA Technical Reports Server (NTRS)

    Vongierke, H. E.; Brinkley, J. W.

    1975-01-01

    The degree to which impact acceleration is an important factor in space flight environments depends primarily upon the technology of capsule landing deceleration and the weight permissible for the associated hardware: parachutes or deceleration rockets, inflatable air bags, or other impact attenuation systems. The problem most specific to space medicine is the potential change of impact tolerance due to reduced bone mass and muscle strength caused by prolonged weightlessness and physical inactivity. Impact hazards, tolerance limits, and human impact tolerance related to space missions are described.

  19. Low TLR7 gene expression in atherosclerotic plaques is associated with major adverse cardio- and cerebrovascular events

    PubMed Central

    Karadimou, Glykeria; Folkersen, Lasse; Berg, Martin; Perisic, Ljubica; Discacciati, Andrea; Roy, Joy; Hansson, Göran K.; Persson, Jonas; Paulsson-Berne, Gabrielle

    2017-01-01

    Aims Processes in the development of atherosclerotic lesions can lead to plaque rupture or erosion, which can in turn elicit myocardial infarction or ischaemic stroke. The aims of this study were to determine whether Toll-like receptor 7 (TLR7) gene expression levels influence patient outcome and to explore the mechanisms linked to TLR7 expression in atherosclerosis. Methods and results Atherosclerotic plaques were removed by carotid endarterectomy (CEA) and subjected to gene array expression analysis (n = 123). Increased levels of TLR7 transcript in the plaques were associated with better outcome in a follow-up study over a maximum of 8 years. Patients with higher TLR7 transcript levels had a lower risk of experiencing major cardiovascular and cerebrovascular events (MACCE) during the follow-up period after CEA (hazard ratio: 2.38, P = 0.012, 95% CI 1.21–4.67). TLR7 was expressed in all plaques by T cells, macrophages and endothelial cells in capillaries, as shown by immunohistochemistry. In short-term tissue cultures, ex vivo treatment of plaques with the TLR7 ligand imiquimod elicited dose-dependent secretion of IL-10, TNF-α, GM-CSF, and IL-12/IL-23p40. This secretion was blocked with a TLR7 inhibitor. Immunofluorescent tissue analysis after TLR7 stimulation showed IL-10 expression in T cells, macrophages and vascular smooth muscle cells. TLR7 mRNA levels in the plaques were correlated with IL-10 receptor (r = 0.4031, P < 0.0001) and GM-CSF receptor A (r = 0.4354, P < 0.0001) transcripts. Conclusion These findings demonstrate that TLR7 is abundantly expressed in human atherosclerotic plaques. TLR7 ligation elicits the secretion of pro-inflammatory and anti-inflammatory cytokines, and high TLR7 expression in plaques is associated with better patient outcome, suggesting that TLR7 is a potential therapeutic target for prevention of complications of atherosclerosis. PMID:27864310

  20. Accelerated oxidation processes is biodiesel

    SciTech Connect

    Canakci, M.; Monyem, A.; Van Gerpen, J.

    1999-12-01

    Biodiesel is an alternative fuel for diesel engines that can be produced from renewable feedstocks such as vegetable oil and animal fats. These feedstocks are reacted with an alcohol to produce alkyl monoesters that can be used in conventional diesel engines with little or no modification. Biodiesel, especially if produced from highly unsaturated oils, oxidizes more rapidly than diesel fuel. This article reports the results of experiments to track the chemical and physical changes that occur in biodiesel as it oxidizes. These results show the impact of time, oxygen flow rate, temperature, metals, and feedstock type on the rate of oxidation. Blending with diesel fuel and the addition of antioxidants are explored also. The data indicate that without antioxidants, biodiesel will oxidize very quickly at temperatures typical of diesel engines. This oxidation results in increases in peroxide value, acid value, and viscosity. While the peroxide value generally reaches a plateau of about 350 meq/kg ester, the acid value and viscosity increase monotonically as oxidation proceeds.

  1. Diffusive Shock Acceleration

    NASA Astrophysics Data System (ADS)

    Baring, Matthew

    2003-04-01

    The process of diffusive acceleration of charged particles in shocked plasmas is widely invoked in astrophysics to account for the ubiquitous presence of signatures of non-thermal relativistic electrons and ions in the universe. This statistical energization mechanism, manifested in turbulent media, was first posited by Enrico Fermi in 1949 to explain the observed cosmic ray population, which exhibits an almost power-law distribution in rigidity. The absence of a momentum scale is a key characteristic of diffusive shock acceleration, and astrophysical systems generally only impose scales at the injection (low energy) and loss (high energy) ends of the particle spectrum. The existence of structure in the cosmic ray spectrum (the "knee") at around 3000 TeV has promoted contentions that there are at least two origins for cosmic rays, a galactic one supplying those up to the knee, and perhaps an extragalactic one that can explain even the ultra-high energy cosmic rays (UHECRs) seen at 1-300 EeV. Accounting for the UHECRs with familiar astrophysical sites of acceleration has historically proven difficult due to the need to assume high magnetic fields in order to reduce the shortest diffusive acceleration timescale, the ion gyroperiod, to meaningful values. Yet active galaxies and gamma-ray bursts remain strong and interesting candidate sources for UHECRs, turning the theoretical focus to relativistic shocks. This review summarizes properties of diffusive shock acceleration that are salient to the issue of UHECR generation. These include spectral indices, anisotropies, acceleration efficencies and timescales, as functions of the shock speed and mean field orientation, and also the degree of field turbulence. Astrophysical sites for UHECR production are also critiqued.

  2. Integration Tests of the 4 kW-Class High Voltage Hall Accelerator Power Processing Unit with the HiVHAc and the SPT-140 Hall Effect Thrusters

    NASA Technical Reports Server (NTRS)

    Kamhawi, Hani; Pinero, Luis; Haag, Thomas; Huang, Wensheng; Ahern, Drew; Liang, Ray; Shilo, Vlad

    2016-01-01

    NASA's Science Mission Directorate is sponsoring the development of a 4 kW-class Hall propulsion system for implementation in NASA science and exploration missions. The main components of the system include the High Voltage Hall Accelerator (HiVHAc), an engineering model power processing unit (PPU) developed by Colorado Power Electronics, and a xenon flow control module (XFCM) developed by VACCO Industries. NASA Glenn Research Center is performing integrated tests of the Hall thruster propulsion system. This paper presents results from integrated tests of the PPU and XFCM with the HiVHAc engineering development thruster and a SPT-140 thruster provided by Space System Loral. The results presented in this paper demonstrate thruster discharge initiation along with open-loop and closed-loop control of the discharge current with anode flow for both the HiVHAc and the SPT-140 thrusters. Integrated tests with the SPT-140 thruster indicated that the PPU was able to repeatedly initiate the thruster's discharge, achieve steady state operation, and successfully throttle the thruster between 1.5 and 4.5 kW. The measured SPT-140 performance was identical to levels reported by Space Systems Loral.

  3. Accelerator system and method of accelerating particles

    NASA Technical Reports Server (NTRS)

    Wirz, Richard E. (Inventor)

    2010-01-01

    An accelerator system and method that utilize dust as the primary mass flux for generating thrust are provided. The accelerator system can include an accelerator capable of operating in a self-neutralizing mode and having a discharge chamber and at least one ionizer capable of charging dust particles. The system can also include a dust particle feeder that is capable of introducing the dust particles into the accelerator. By applying a pulsed positive and negative charge voltage to the accelerator, the charged dust particles can be accelerated thereby generating thrust and neutralizing the accelerator system.

  4. Ultrasound imaging versus morphopathology in cardiovascular diseases. Coronary collateral circulation and atherosclerotic plaque

    PubMed Central

    Baroldi, Giorgio; Bigi, Riccardo; Cortigiani, Lauro

    2005-01-01

    This review article is aimed at comparing the results of histopathological and clinical imaging studies to assess coronary collateral circulation in humans. The role of collaterals, as emerging from morphological studies in both normal and atherosclerotic coronary vessels, is described; in addition, present role and future perpectives of echocardiographic techniques in assessing collateral circulation are briefly summarized. PMID:15740620

  5. Indium-111-labeled LDL: A potential agent for imaging atherosclerotic disease and lipoprotein biodistribution

    SciTech Connect

    Rosen, J.M.; Butler, S.P.; Meinken, G.E.; Wang, T.S.; Ramakrishnan, R.; Srivastava, S.C.; Alderson, P.O.; Ginsberg, H.N. )

    1990-03-01

    Radiolabeling of low-density lipoprotein (LDL) and external imaging with a gamma camera would offer a means of taking advantage of the metabolic activity of developing atherosclerotic lesions in order to noninvasively detect and determine the extent of atherosclerotic cardiovascular disease. Indium-111-({sup 111}In) labeled LDL was prepared and its purity demonstrated by agarose electrophoresis and ultracentrifugation. In vitro studies with cultured human fibroblasts demonstrated significant inhibition of iodine-125-({sup 125}I) LDL binding to LDL receptors by {sup 111}In-LDL, although this was less than the inhibition produced by unlabeled LDL. Adrenal gland uptake of {sup 111}In-LDL by hypercholesterolemic rabbits was reduced by 86% compared to the level of uptake observed in normal rabbits. These results were compatible with downregulation of adrenal LDL receptors in the hypercholesterolemic rabbits. Uptake of {sup 111}In-LDL in the atherosclerotic proximal aorta of hypercholesterolemic rabbits was 2.5 times higher than in normal rabbits. These results suggest that {sup 111}In-LDL has the potential to be a useful agent for external imaging of atherosclerotic lesions and lipoprotein biodistribution.

  6. Prednisolone-containing liposomes accumulate in human atherosclerotic macrophages upon intravenous administration

    PubMed Central

    van der Valk, Fleur M.; van Wijk, Diederik F.; Lobatto, Mark E.; Verberne, Hein J.; Storm, Gert; Willems, Martine C.M.; Legemate, Dink A.; Nederveen, Aart J.; Calcagno, Claudia; Mani, Venkatesh; Ramachandran, Sarayu; Paridaans, Maarten P.M.; Otten, Maarten J.; Dallinga-Thie, Geesje M.; Fayad, Zahi A.; Nieuwdorp, Max; Schulte, Dominik M.; Metselaar, Josbert M.; Mulder, Willem J.M.; Stroes, Erik S.

    2015-01-01

    Drug delivery to atherosclerotic plaques via liposomal nanoparticles may improve therapeutic agents’ risk–benefit ratios. Our paper details the first clinical studies of a liposomal nanoparticle encapsulating prednisolone (LN-PLP) in atherosclerosis. First, PLP’s liposomal encapsulation improved its pharmacokinetic profile in humans (n = 13) as attested by an increased plasma half-life of 63 h (LN-PLP 1.5 mg/kg). Second, intravenously infused LN-PLP appeared in 75% of the macrophages isolated from iliofemoral plaques of patients (n = 14) referred for vascular surgery in a randomized, placebo-controlled trial. LN-PLP treatment did however not reduce arterial wall permeability or inflammation in patients with atherosclerotic disease (n = 30), as assessed by multimodal imaging in a subsequent randomized, placebo-controlled study. In conclusion, we successfully delivered a long-circulating nanoparticle to atherosclerotic plaque macrophages in patients, whereas prednisolone accumulation in atherosclerotic lesions had no anti-inflammatory effect. Nonetheless, the present study provides guidance for development and imaging-assisted evaluation of future nanomedicine in atherosclerosis. PMID:25791806

  7. Annexin A5-Functionalized Bimodal Nanoparticles for MRI and Fluorescence Imaging of Atherosclerotic Plaques

    PubMed Central

    van Tilborg, Geralda A. F.; Vucic, Esad; Strijkers, Gustav J.; Cormode, David P.; Mani, Venkatesh; Skajaa, Torjus; Reutelingsperger, Chris P. M.; Fayad, Zahi A.; Mulder, Willem J. M.; Nicolay, Klaas

    2011-01-01

    Apoptosis and macrophage burden are believed to correlate with atherosclerotic plaque vulnerability and are therefore considered important diagnostic and therapeutic targets for atherosclerosis. These cell types are characterized by the exposure of phosphatidylserine (PS) at their surface. In the present study, we developed and applied a small micellar fluorescent annexin A5-functionalized nanoparticle for noninvasive magnetic resonance imaging (MRI) of PS exposing cells in atherosclerotic lesions. Annexin A5-mediated target-specificity was confirmed with ellipsometry and in vitro binding to apoptotic Jurkat cells. In vivo T1-weighted MRI of the abdominal aorta in atherosclerotic ApoE−/− mice revealed enhanced uptake of the annexin A5-micelles as compared to control-micelles, which was corroborated with ex vivo near-infrared fluorescence images of excised whole aortas. Confocal laser scanning microscopy (CLSM) demonstrated that the targeted agent was associated with macrophages and apoptotic cells, whereas the nonspecific control agent showed no clear uptake by such cells. In conclusion, the annexin A5-conjugated bimodal micelles displayed potential for noninvasive assessment of cell types that are considered to significantly contribute to plaque instability and therefore may be of great value in the assessment of atherosclerotic lesion phenotype. PMID:20804153

  8. Atherosclerotic Lesion Progression Changes Lysophosphatidic Acid Homeostasis to Favor its Accumulation

    PubMed Central

    Bot, Martine; Bot, Ilze; Lopez-Vales, Rubén; van de Lest, Chris H.A.; Saulnier-Blache, Jean Sébastien; Helms, J. Bernd; David, Samuel; van Berkel, Theo J.C.; Biessen, Erik A.L.

    2010-01-01

    Lysophosphatidic acid (LPA) accumulates in the central atheroma of human atherosclerotic plaques and is the primary platelet-activating lipid constituent of plaques. Here, we investigated the enzymatic regulation of LPA homeostasis in atherosclerotic lesions at various stages of disease progression. Atherosclerotic lesions were induced in carotid arteries of low-density lipoprotein receptor–deficient mice by semiconstrictive collar placement. At 2-week intervals after collar placement, lipids and RNA were extracted from the vessel segments carrying the plaque. Enzymatic-and liquid chromatography-mass spectrometry–based lipid profiling revealed progressive accumulation of LPA species in atherosclerotic tissue preceded by an increase in lysophosphatidylcholine, a precursor in LPA synthesis. Plaque expression of LPA-generating enzymes cytoplasmic phospholipase A2IVA (cPLA2IVA) and calcium-independent PLA2VIA (iPLA2VIA) was gradually increased, whereas that of the LPA-hydrolyzing enzyme LPA acyltransferase α was quenched. Increased expression of cPLA2IVA and iPLA2VIA in advanced lesions was confirmed by immunohistochemistry. Moreover, LPA receptors 1 and 2 were 50% decreased and sevenfold upregulated, respectively. Therefore, key proteins in LPA homeostasis are increasingly dysregulated in the plaque during atherogenesis, favoring intracellular LPA production. This might at least partly explain the observed progressive accumulation of this thrombogenic proinflammatory lipid in human and mouse plaques. Thus, intervention in the enzymatic LPA production may be an attractive measure to lower intraplaque LPA content, thereby reducing plaque progression and thrombogenicity. PMID:20431029

  9. Detection of atherosclerotic lesions and intimal macrophages using CD36-targeted nanovesicles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Current approaches to the diagnosis and therapy of atherosclerosis cannot target to lesion-determinant cells in the artery wall. Intimal macrophage infiltration promotes atherosclerotic lesion development by facilitating the accumulation of oxidized low-density lipoproteins (oxLDL) and increasing in...

  10. Characterization of atherosclerotic arterial tissue using combined SHG and FLIM microscopy

    NASA Astrophysics Data System (ADS)

    Cicchi, Riccardo; Baria, Enrico; Matthäus, Christian; Lange, Marta; Lattermann, Annika; Brehm, Bernhard R.; Popp, Jürgen; Pavone, Francesco S.

    2015-07-01

    Atherosclerosis is among the most widespread cardiovascular diseases and one of the leading cause of death in the Western World. Characterization of arterial tissue in atherosclerotic condition is extremely interesting from the diagnostic point of view, especially for what is concerning collagen content and organization because collagen plays a crucial role in plaque vulnerability. Routinely used diagnostic methods, such as histopathological examination, are limited to morphological analysis of the examined tissues, whereas an exhaustive characterization requires immunehistochemical examination and a morpho-functional approach. Non-linear microscopy techniques offer the potential for providing morpho-functional information on the examined tissues in a label-free way. In this study, we employed combined SHG and FLIM microscopy for characterizing collagen organization in both normal arterial wall and within atherosclerotic plaques. Image pattern analysis of SHG images allowed characterizing collagen organization in different tissue regions. In addition, the analysis of collagen fluorescence decay contributed to the characterization of the samples based on collagen fluorescence lifetime. Different values of collagen fiber mean size, collagen distribution, and collagen anisotropy and collagen fluorescence lifetime were found in normal arterial wall and within plaque depositions, prospectively allowing for automated classification of atherosclerotic lesions and plaque vulnerability. The presented method represents a promising diagnostic tool for evaluating atherosclerotic tissue and has the potential to find a stable place in clinical setting as well as to be applied in vivo in the near future.

  11. A framework for the co-registration of hemodynamic forces and atherosclerotic plaque components

    PubMed Central

    Chiu, Bernard; Chen, Huijun; Chen, Yimin; Hatsukami, Thomas S.; Kerwin, William S.; Yuan, Chun

    2013-01-01

    Local hemodynamic forces, such as wall shear stress, are thought to trigger cellular and molecular mechanisms that determine atherosclerotic plaque vulnerability to rupture. Magnetic resonance imaging (MRI) has emerged as a powerful tool to characterize human carotid atherosclerotic plaque composition and morphology, and to identify plaque features shown to be key determinants of plaque vulnerability. Image-based computational fluid dynamics (CFD) has allowed researchers to obtain time-resolved wall shear stress (WSS) information of atherosclerotic carotid arteries. A deeper understanding of the mechanisms of initiation and progression of atherosclerosis can be obtained through the comparison of WSS and plaque composition and morphology. To date, however, advance in knowledge has been limited greatly due to the lack of a reliable infrastructure to perform such analysis. The aim of this study is to establish a framework that will allow for the co-registration and analysis of the three-dimensional (3D) distribution ofWSS and plaque components and morphology. The use of this framework will lead to future studies targeted to determining the role of WSS in atherosclerotic plaque progression and vulnerability. PMID:23945133

  12. Distinct metabolic and vascular effects of dietary triglycerides and cholesterol in atherosclerotic and diabetic mouse models.

    PubMed

    Laplante, Marc-André; Charbonneau, Alexandre; Avramoglu, Rita Kohen; Pelletier, Patricia; Fang, Xiangping; Bachelard, Hélène; Ylä-Herttuala, Seppo; Laakso, Markku; Després, Jean-Pierre; Deshaies, Yves; Sweeney, Gary; Mathieu, Patrick; Marette, André

    2013-09-01

    Cholesterol and triglyceride-rich Western diets are typically associated with an increased occurrence of type 2 diabetes and vascular diseases. This study aimed to assess the relative impact of dietary cholesterol and triglycerides on glucose tolerance, insulin sensitivity, atherosclerotic plaque formation, and endothelial function. C57BL6 wild-type (C57) mice were compared with atherosclerotic LDLr(-/-) ApoB(100/100) (LRKOB100) and atherosclerotic/diabetic IGF-II × LDLr(-/-) ApoB(100/100) (LRKOB100/IGF) mice. Each group was fed either a standard chow diet, a 0.2% cholesterol diet, a high-fat diet (HFD), or a high-fat 0.2% cholesterol diet for 6 mo. The triglyceride-rich HFD increased body weight, glucose intolerance, and insulin resistance but did not alter endothelial function or atherosclerotic plaque formation. Dietary cholesterol, however, increased plaque formation in LRKOB100 and LRKOB100/IGF animals and decreased endothelial function regardless of genotype. However, cholesterol was not associated with an increase of insulin resistance in LRKOB100 and LRKOB100/IGF mice and, unexpectedly, was even found to reduce the insulin-resistant effect of dietary triglycerides in these animals. Our data indicate that dietary triglycerides and cholesterol have distinct metabolic and vascular effects in obese atherogenic mouse models resulting in dissociation between the impairment of glucose homeostasis and the development of atherosclerosis.

  13. VCAM-1-targeting gold nanoshell probe for photoacoustic imaging of atherosclerotic plaque in mice.

    PubMed

    Rouleau, Leonie; Berti, Romain; Ng, Vanessa W K; Matteau-Pelletier, Carl; Lam, Tina; Saboural, Pierre; Kakkar, Ashok K; Lesage, Frédéric; Rhéaume, Eric; Tardif, Jean-Claude

    2013-01-01

    The development of molecular probes and novel imaging modalities, allowing better resolution and specificity, is associated with an increased potential for molecular imaging of atherosclerotic plaques especially in basic and pre-clinical research applications. In that context, a photoacoustic molecular probe based on gold nanoshells targeting VCAM-1 in mice (immunonanoshells) was designed. The molecular probe was validated in vitro and in vivo, showing no noticeable acute toxic effects. We performed the conjugation of gold nanoshells displaying near-infrared absorption properties with VCAM-1 antibody molecules and PEG to increase their biocompatibility. The resulting immunonanoshells obtained under different conditions of conjugation were then assessed for specificity and sensitivity. Photoacoustic tomography was performed to determine the ability to distinguish gold nanoshells from blood both in phantoms and in vivo. Ex vivo optical projection tomography of hearts and aortas from atherosclerotic and control mice confirmed the selective accumulation of the immunonanoshells in atherosclerotic-prone regions in mice, thus validating the utility of the probe in vivo in small animals for pre-clinical research. These immunonanoshells represent an adequate mean to target atherosclerotic plaques in small animals, leading to new tools to follow the effect of therapies on the progression or regression of the disease.

  14. Differentially expressed genes and canonical pathway expression in human atherosclerotic plaques – Tampere Vascular Study

    PubMed Central

    Sulkava, Miska; Raitoharju, Emma; Levula, Mari; Seppälä, Ilkka; Lyytikäinen, Leo-Pekka; Mennander, Ari; Järvinen, Otso; Zeitlin, Rainer; Salenius, Juha-Pekka; Illig, Thomas; Klopp, Norman; Mononen, Nina; Laaksonen, Reijo; Kähönen, Mika; Oksala, Niku; Lehtimäki, Terho

    2017-01-01

    Cardiovascular diseases due to atherosclerosis are the leading cause of death globally. We aimed to investigate the potentially altered gene and pathway expression in advanced peripheral atherosclerotic plaques in comparison to healthy control arteries. Gene expression analysis was performed (Illumina HumanHT-12 version 3 Expression BeadChip) for 68 advanced atherosclerotic plaques (15 aortic, 29 carotid and 24 femoral plaques) and 28 controls (left internal thoracic artery (LITA)) from Tampere Vascular Study. Dysregulation of individual genes was compared to healthy controls and between plaques from different arterial beds and Ingenuity pathway analysis was conducted on genes with a fold change (FC) > ±1.5 and false discovery rate (FDR) < 0.05. 787 genes were significantly differentially expressed in atherosclerotic plaques. The most up-regulated genes were osteopontin and multiple MMPs, and the most down-regulated were cell death-inducing DFFA-like effector C and A (CIDEC, CIDEA) and apolipoprotein D (FC > 20). 156 pathways were differentially expressed in atherosclerotic plaques, mostly inflammation-related, especially related with leukocyte trafficking and signaling. In artery specific plaque analysis 50.4% of canonical pathways and 41.2% GO terms differentially expressed were in common for all three arterial beds. Our results confirm the inflammatory nature of advanced atherosclerosis and show novel pathway differences between different arterial beds. PMID:28128285

  15. Non-linear imaging and characterization of atherosclerotic arterial tissue using combined SHG and FLIM microscopy

    NASA Astrophysics Data System (ADS)

    Cicchi, Riccardo; Matthäus, Christian; Meyer, Tobias; Lattermann, Annika; Dietzek, Benjamin; Brehm, Bernhard R.; Popp, Jürgen; Pavone, Francesco S.

    2015-03-01

    Atherosclerosis is among the most widespread cardiovascular diseases and one of the leading cause of death in the Western World. Characterization of arterial tissue in atherosclerotic condition is extremely interesting from the diagnostic point of view, especially for what is concerning collagen content and organization because collagen plays a crucial role in plaque vulnerability. Routinely used diagnostic methods, such as histopathological examination, are limited to morphological analysis of the examined tissues, whereas an exhaustive characterization requires immune-histochemical examination and a morpho-functional approach. Non-linear microscopy techniques offer the potential for providing morpho-functional information on the examined tissues in a label-free way. In this study, we employed combined SHG and FLIM microscopy for characterizing collagen organization in both normal arterial wall and within atherosclerotic plaques. Image pattern analysis of SHG images allowed characterizing collagen organization in different tissue regions. In addition, the analysis of collagen fluorescence decay contributed to the characterization of the samples on the basis of collagen fluorescence lifetime. Different values of collagen fiber mean size, collagen distribution, collagen anisotropy and collagen fluorescence lifetime were found in normal arterial wall and within plaque depositions, prospectively allowing for automated classification of atherosclerotic lesions and plaque vulnerability. The presented method represents a promising diagnostic tool for evaluating atherosclerotic tissue and has the potential to find a stable place in clinical setting as well as to be applied in vivo in the near future.

  16. Lysophosphatidic acid triggers mast cell-driven atherosclerotic plaque destabilization by increasing vascular inflammation.

    PubMed

    Bot, Martine; de Jager, Saskia C A; MacAleese, Luke; Lagraauw, H Maxime; van Berkel, Theo J C; Quax, Paul H A; Kuiper, Johan; Heeren, Ron M A; Biessen, Erik A L; Bot, Ilze

    2013-05-01

    Lysophosphatidic acid (LPA), a bioactive lysophospholipid, accumulates in the atherosclerotic plaque. It has the capacity to activate mast cells, which potentially exacerbates plaque progression. In this study, we thus aimed to investigate whether LPA contributes to plaque destabilization by modulating mast cell function. We here show by an imaging mass spectrometry approach that several LPA species are present in atherosclerotic plaques. Subsequently, we demonstrate that LPA is a potent mast cell activator which, unlike other triggers, favors release of tryptase. Local perivascular administration of LPA to an atherosclerotic carotid artery segment increases the activation status of perivascular mast cells and promotes intraplaque hemorrhage and macrophage recruitment without impacting plaque cell apoptosis. The mast cell stabilizer cromolyn could prevent intraplaque hemorrhage elicited by LPA-mediated mast cell activation. Finally, the involvement of mast cells in these events was further emphasized by the lack of effect of perivascular LPA administration in mast cell deficient animals. We demonstrate that increased accumulation of LPA in plaques induces perivascular mast cell activation and in this way contributes to plaque destabilization in vivo. This study points to local LPA availability as an important factor in atherosclerotic plaque stability.

  17. Monolithic Composite “Pressure + Acceleration + Temperature + Infrared” Sensor Using a Versatile Single-Sided “SiN/Poly-Si/Al” Process-Module

    PubMed Central

    Ni, Zao; Yang, Chen; Xu, Dehui; Zhou, Hong; Zhou, Wei; Li, Tie; Xiong, Bin; Li, Xinxin

    2013-01-01

    We report a newly developed design/fabrication module with low-cost single-sided “low-stress-silicon-nitride (LS-SiN)/polysilicon (poly-Si)/Al” process for monolithic integration of composite sensors for sensing-network-node applications. A front-side surface-/bulk-micromachining process on a conventional Si-substrate is developed, featuring a multifunctional SiN/poly-Si/Al layer design for diverse sensing functions. The first “pressure + acceleration + temperature + infrared” (PATIR) composite sensor with the chip size of 2.5 mm × 2.5 mm is demonstrated. Systematic theoretical design and analysis methods are developed. The diverse sensing components include a piezoresistive absolute-pressure sensor (up to 700 kPa, with a sensitivity of 49 mV/MPa under 3.3 V supplied voltage), a piezoresistive accelerometer (±10 g, with a sensitivity of 66 μV/g under 3.3 V and a −3 dB bandwidth of 780 Hz), a thermoelectric infrared detector (with a responsivity of 45 V/W and detectivity of 3.6 × 107 cm·Hz1/2/W) and a thermistor (−25–120 °C). This design/fabrication module concept enables a low-cost monolithically-integrated “multifunctional-library” technique. It can be utilized as a customizable tool for versatile application-specific requirements, which is very useful for small-size, low-cost, large-scale sensing-network node developments. PMID:23325169

  18. Spanning from the West to East: An Updated Review on Endovascular Treatment of Intracranial Atherosclerotic Disease.

    PubMed

    Hussain, Mohammed; Datta, Neil; Cheng, Zhe; Dornbos, David; Bashir, Asif; Sultan, Ibrahim; Mehta, Tapan; Shweikeh, Faris; Mazaris, Paul; Lee, Nora; Nouh, Amre; Geng, Xiaokun; Ding, Yuchuan

    2017-04-01

    Ischemic stroke is a major cause of morbidity and mortality, incurring significant cost. Intracranial atherosclerotic disease (ICAD) accounts for 10-15% of ischemic stroke in Western societies, but is an underlying pathology in up to 54% of ischemic strokes in Asian populations. ICAD has largely been treated with medical management, although a few studies have examined outcomes following endovascular treatment. Our objective was to summarize the major trials that have been performed thus far in regard to the endovascular treatment of ICAD and to provide direction for future management of this disease process. Systematic review of the literature from 1966 to 2015, was conducted in regard to intracranial angioplasty and stenting. Studies were analyzed from PubMed, American Heart Association and Society of Neurointerventional Surgery databases. SAMMPRIS and VISSIT are the only randomized controlled trials from which Western guidelines of intracranial stenting have been derived, which have displayed the superiority of medical management. However, pooled reviews of smaller studies and other nonrandomized trials have shown better outcomes with endovascular therapy in select patient subsets, such as intracranial vertebrobasilar stenosis or in the presence of robust collaterals. Suboptimal cases, including longer lesions, bifurcations and significant tortuosity tend to fair better with medical management. Medical management has been shown to be more efficacious with less adverse outcomes than endovascular therapy. However, the majority of studies on endovascular management included a diverse patient population without ideal selection criteria, resulting in higher adverse outcomes. Population analyses and selective utilization of endovascular therapy have shown that the treatment may be superior to other management in select patients.

  19. Spanning from the West to East: An Updated Review on Endovascular Treatment of Intracranial Atherosclerotic Disease

    PubMed Central

    Hussain, Mohammed; Datta, Neil; Cheng, Zhe; Dornbos, David; Bashir, Asif; Sultan, Ibrahim; Mehta, Tapan; Shweikeh, Faris; Mazaris, Paul; Lee, Nora; Nouh, Amre; Geng, Xiaokun; Ding, Yuchuan

    2017-01-01

    Ischemic stroke is a major cause of morbidity and mortality, incurring significant cost. Intracranial atherosclerotic disease (ICAD) accounts for 10-15% of ischemic stroke in Western societies, but is an underlying pathology in up to 54% of ischemic strokes in Asian populations. ICAD has largely been treated with medical management, although a few studies have examined outcomes following endovascular treatment. Our objective was to summarize the major trials that have been performed thus far in regard to the endovascular treatment of ICAD and to provide direction for future management of this disease process. Systematic review of the literature from 1966 to 2015, was conducted in regard to intracranial angioplasty and stenting. Studies were analyzed from PubMed, American Heart Association and Society of Neurointerventional Surgery databases. SAMMPRIS and VISSIT are the only randomized controlled trials from which Western guidelines of intracranial stenting have been derived, which have displayed the superiority of medical management. However, pooled reviews of smaller studies and other nonrandomized trials have shown better outcomes with endovascular therapy in select patient subsets, such as intracranial vertebrobasilar stenosis or in the presence of robust collaterals. Suboptimal cases, including longer lesions, bifurcations and significant tortuosity tend to fair better with medical management. Medical management has been shown to be more efficacious with less adverse outcomes than endovascular therapy. However, the majority of studies on endovascular management included a diverse patient population without ideal selection criteria, resulting in higher adverse outcomes. Population analyses and selective utilization of endovascular therapy have shown that the treatment may be superior to other management in select patients.

  20. Stroke radiology and distinguishing characteristics of intracranial atherosclerotic disease in native South Asian Pakistanis

    PubMed Central

    Khan, Maria; Rasheed, Asif; Hashmi, Saman; Zaidi, Moazzam; Murtaza, Muhammad; Akhtar, Saba; Bansari, Lajpat; Shah, Nabi; Samuel, Maria; Raza, Sadaf; Khan, Umer Rais; Ahmed, Bilal; Ahmed, Bilawal; Ahmed, Naveeduddin; Ara, Jamal; Ahsan, Tasnim; Munir, S. M.; Ali, Shoukat; Mehmood, Khalid; Maki, Karim Ullah; Ahmed, Muhammad Masroor; Sheikh, Niaz; Memon, Abdul Rauf; Frossard, Philippe M.; Kamal, Ayeesha Kamran

    2012-01-01

    Background There are no descriptions of stroke mechanisms from intracranial atherosclerotic disease (ICAD) in native South Asian Pakistanis. Methods Men and women aged >/= 18 years with acute stroke presenting to four tertiary care hospitals in Karachi, Pakistan were screened using Magnetic Resonance Angiography/Transcranial Doppler scans. TOAST criteria were applied to identify strokes from ICAD. Results 245 patients with acute stroke due to ICAD were studied. 230 scans were reviewed. 206 /230(89.0%) showed acute ischemia. The most frequent presentation was with cortically based strokes in 42.2% (87/206) followed by border zone infarcts (52/206, 25.2%).Increasing degrees of stenosis correlated with the development of both cortical and border zone strokes (p=.002). Important associated findings were frequent atrophy (166/230, 72.2%) silent brain infarcts (66/230, 28%) and a marked lack of severe leukoaraiosis identified in only 68 /230 (29.6 %). A total of 1870 arteries were studied individually. MCA was the symptomatic stroke vessel in half, presenting with complete occlusion in 66%. Evidence of biological disease, symptomatic or asymptomatic was identified in 753 (40.2%) vessels of which 543 (72%) were significantly (>50%) stenosed at presentation. Conclusion ICAD is a diffuse process in Pakistani South Asians, with involvement of multiple vessels in addition to the symptomatic vessel. The MCA is the most frequent symptomatic vessel presenting with cortical embolic infarcts. There is a relative lack of leukoaraiosis. Concomitant atrophy, silent brain infarcts and recent ischemia in the symptomatic territory are all frequently associated findings. PMID:23013556

  1. Meta-analysis of the effects of lifestyle modifications on coronary and carotid atherosclerotic burden.

    PubMed

    Jhamnani, Sunny; Patel, Dhavalkumar; Heimlich, Layla; King, Fred; Walitt, Brian; Lindsay, Joseph

    2015-01-15

    Lifestyle modifications are the crux of atherosclerotic disease management. The goal of this study was to determine the effectiveness of diet and exercise in decreasing coronary and carotid atherosclerotic burden. Randomized controlled trials examining the effects of intensive lifestyle measures on atherosclerotic progression in coronary and carotid arteries as measured by baseline and follow-up quantitative coronary angiogram and ultrasonographic carotid intimal-medial thickness (CIMT), respectively, were included. Studies were excluded if the intervention additionally included a medication. MEDLINE, EMBASE, CINAHL, Cochrane Controlled Trials Registers, reports, and abstracts from major cardiology meetings were searched by 2 researchers independently and verified by the primary investigator. Standardized mean difference (SMD) with 95% confidence intervals (CIs) was calculated using random-effects model. Publication bias and heterogeneity were assessed. Fourteen trials were included. Seven used quantitative coronary angiogram, and 7 used CIMT; 1,343 lesions in 340 patients in the coronary group and 919 patients in the carotid group were analyzed. Overall, lifestyle modifications were associated with a decrease in coronary atherosclerotic burden in percent stenosis by -0.34 (95% CI -0.48 to -0.21) SMD, with no significant publication bias and heterogeneity (p = 0.21, I(2) = 28.25). Similarly, in the carotids, there was a decrease in the CIMT, in millimeter, by -0.21 (95% CI -0.36 to -0.05) SMD and by -0.13 (95% CI -0.25 to -0.02) SMD, before and after accounting for publication bias and heterogeneity (p = 0.13, I(2) = 39.91; p = 0.54, I(2) = 0), respectively. In conclusion, these results suggest that intensive lifestyle modifications are associated with a decrease in coronary and carotid atherosclerotic burden.

  2. Xyloketal B Attenuates Atherosclerotic Plaque Formation and Endothelial Dysfunction in Apolipoprotein E Deficient Mice

    PubMed Central

    Zhao, Li-Yan; Li, Jie; Yuan, Feng; Li, Mei; Zhang, Quan; Huang, Yun-Ying; Pang, Ji-Yan; Zhang, Bin; Sun, Fang-Yun; Sun, Hong-Shuo; Li, Qian; Cao, Lu; Xie, Yu; Lin, Yong-Cheng; Liu, Jie; Tan, Hong-Mei; Wang, Guan-Lei

    2015-01-01

    Our previous studies demonstrated that xyloketal B, a novel marine compound with a unique chemical structure, has strong antioxidant actions and can protect against endothelial injury in different cell types cultured in vitro and model organisms in vivo. The oxidative endothelial dysfunction and decrease in nitric oxide (NO) bioavailability are critical for the development of atherosclerotic lesion. We thus examined whether xyloketal B had an influence on the atherosclerotic plaque area in apolipoprotein E-deficient (apoE−/−) mice fed a high-fat diet and investigated the underlying mechanisms. We found in our present study that the administration of xyloketal B dose-dependently decreased the atherosclerotic plaque area both in the aortic sinus and throughout the aorta in apoE−/− mice fed a high-fat diet. In addition, xyloketal B markedly reduced the levels of vascular oxidative stress, as well as improving the impaired endothelium integrity and NO-dependent aortic vasorelaxation in atherosclerotic mice. Moreover, xyloketal B significantly changed the phosphorylation levels of endothelial nitric oxide synthase (eNOS) and Akt without altering the expression of total eNOS and Akt in cultured human umbilical vein endothelial cells (HUVECs). Here, it increased eNOS phosphorylation at the positive regulatory site of Ser-1177, while inhibiting phosphorylation at the negative regulatory site of Thr-495. Taken together, these findings indicate that xyloketal B has dramatic anti-atherosclerotic effects in vivo, which is partly due to its antioxidant features and/or improvement of endothelial function. PMID:25874925

  3. Isolation and characterization of a complement-activating lipid extracted from human atherosclerotic lesions

    PubMed Central

    1990-01-01

    The major characteristics of human atherosclerotic lesions are similar to those of a chronic inflammatory reaction, namely fibrosis, mesenchymal cell proliferation, the presence of resident macrophages, and cell necrosis. Atherosclerosis exhibits in addition the feature of lipid (mainly cholesterol) accumulation. The results of the present report demonstrate that a specific cholesterol-containing lipid particle present in human atherosclerotic lesions activates the complement system to completion. Thus, lipid could represent a stimulatory factor for the inflammatory reaction, whose underlying mechanistic basis may be, at least in part, complement activation. The complement-activating lipid was purified from saline extracts of aortic atherosclerotic lesions by sucrose density gradient centrifugation followed by molecular sieve chromatography on Sepharose 2B. It contained little protein other than albumin, was 100-500 nm in size, exhibited an unesterified to total cholesterol ratio of 0.58 and an unesterified cholesterol to phospholipid ratio of 1.2. The lipid, termed lesion lipid complement (LCA), activated the alternative pathway of complement in a dose-dependent manner. Lesion-extracted low density lipoprotein (LDL) obtained during the purification procedure failed to activate complement. Specific generation of C3a desArg and C5b-9 by LCA indicated C3/C5 convertase formation with activation proceeding to completion. Biochemical and electron microscopic evaluations revealed that much of the C5b-9 present in atherosclerotic lesions is membraneous, rather than fluid phase SC5b-9. The observations reported herein establish a link between lipid insudation and inflammation in atherosclerotic lesions via the mechanism of complement activation. PMID:2373993

  4. A New Process for the Acceleration Test and Evaluation of Aeromedical Equipment for U.S. Air Force Safe-To-Fly Certification

    DTIC Science & Technology

    2010-10-01

    equipment and successfully introducing the use of the Equivalent Load Testing ( ELT ) method , which permits the use of alternative testing approaches...Data Conduct Acceleration Test Selection Meeting Acceleration Test Type Decision Determine Tasks for Component Level Tests ( ELT Method ) Analyze...mounting brackets, screws, beams, straps, etc. When the decision is a component-level test type, the ATB team applies the ELT method by conducting an in

  5. Observations of particle acceleration in solar flares

    NASA Technical Reports Server (NTRS)

    Hudson, H. S.

    1979-01-01

    Solar flares provide several examples of nonthermal particle acceleration. The paper reviews the information gained about these processes via X-ray and gamma-ray astronomy, which can presently distinguish among three separate particle-acceleration processes at the sun: an impulsive accelerator of more than 20 keV electrons, a gradual accelerator of more than 20 keV electrons, and a gradual accelerator of more than 10 MeV ions. The acceleration energy efficiency (total particle energy divided by total flare energy) of any of these mechanisms cannot be less than about 0.1%, although the gradual acceleration does not occur in every flare. The observational material suggests that both the impulsive and gradual accelerations take place preferentially in closed magnetic-field structures, but that the electrons decay in these traps before they can escape. The ions escape very efficiently.

  6. Acceleration modules in linear induction accelerators

    NASA Astrophysics Data System (ADS)

    Wang, Shao-Heng; Deng, Jian-Jun

    2014-05-01

    The Linear Induction Accelerator (LIA) is a unique type of accelerator that is capable of accelerating kilo-Ampere charged particle current to tens of MeV energy. The present development of LIA in MHz bursting mode and the successful application into a synchrotron have broadened LIA's usage scope. Although the transformer model is widely used to explain the acceleration mechanism of LIAs, it is not appropriate to consider the induction electric field as the field which accelerates charged particles for many modern LIAs. We have examined the transition of the magnetic cores' functions during the LIA acceleration modules' evolution, distinguished transformer type and transmission line type LIA acceleration modules, and re-considered several related issues based on transmission line type LIA acceleration module. This clarified understanding should help in the further development and design of LIA acceleration modules.

  7. Increased activity of guanylate cyclase in the atherosclerotic rabbit aorta: role of non-endothelial nitric oxide synthases.

    PubMed Central

    Rupin, A.; Behr, D.; Verbeuren, T. J.

    1996-01-01

    1. Experiments were performed to examine the effects of putative non-endothelial nitric oxide on the soluble guanylate cyclase activity of severe atherosclerotic aortae from hypercholesterolaemic rabbits fed a cholesterol rich diet for 45 weeks. 2. The guanosine 3':5'-cyclic monophosphate (cyclic GMP) content of aortae from rabbits fed either a control diet or a diet containing 0.3% cholesterol for 45 weeks was quantified in saline extracts or in trichloracetic acid/either extracts by use of a competitive immunoenzymatic assay. Rabbit anti-cyclic GMP immunoglobulin G was covalently linked to the solid phase, in order to avoid false positive results due to high rabbit immunoglobulin G concentrations in the atherosclerotic saline extracts. 3. Saline extracts of atherosclerotic aortae which were harvested immediately after death (intact aortae) contained about 6 fold more cyclic GMP than control aortae when expressed in pmol cyclic GMP mg-1 protein. The cyclic GMP concentrations in trichloracetic acid/ether extracts of atherosclerotic and control aortae expressed in pmol mg-1 fresh tissue were not significantly different. 4. Neointimal-medial explants from atherosclerotic and control aortae were placed in a physiological saline solution and incubated at 37 degrees C for six hours in an incubator gassed with 5% CO2. Before the incubation, the cyclic GMP concentrations in saline extracts of atherosclerotic explants (0.74 +/- 0.27 pmol mg-1) were found to be 17 fold higher than those of control explants (0.043 +/- 0.008 pmol mg-1). The cyclic GMP content of control explants decreased significantly after 6 h of incubation, while that of atherosclerotic explants remained elevated. 5. Chronic administration of NG-nitro-L-arginine methyl ester, a non selective inhibitor of nitric oxide synthases, at 12 mg kg-1 day-1 subcutaneously for one month did not reduce the cyclic GMP concentration of intact atherosclerotic aortae, while that of intact aortae from control rabbits

  8. Advanced glycation end products induce in vitro cross-linking of alpha-synuclein and accelerate the process of intracellular inclusion body formation.

    PubMed

    Shaikh, Shamim; Nicholson, Louise F B

    2008-07-01

    Cross-linking of alpha-synuclein and Lewy body formation have been implicated in the dopaminergic neuronal cell death observed in Parkinson's disease (PD); the mechanisms responsible, however, are not clear. Reactive oxygen species and advanced glycation end products (AGEs) have been found in the intracellular, alpha-synuclein-positive Lewy bodies in the brains of both PD as well as incidental Lewy body disease patients, suggesting a role for AGEs in alpha-synuclein cross-linking and Lewy body formation. The aims of the present study were to determine 1) whether AGEs can induce cross-linking of alpha-synuclein peptides, 2) the progressive and time-dependent intracellular accumulation of AGEs and inclusion body formation, and 3) the effects of extracellular or exogenous AGEs on intracellular inclusion formation. We first investigated the time-dependent cross-linking of recombinant human alpha-synuclein in the presence of AGEs in vitro, then used a cell culture model based on chronic rotenone treatment of human dopaminergic neuroblastoma cells (SH-SY5Y) over a period of 1-4 weeks, in the presence of different doses of AGEs. Cells (grown on coverslips) and cell lysates, collected at the end of every week, were analyzed for the presence of intracellular reactive oxygen species, AGEs, alpha-synuclein proteins, and intracellular alpha-synuclein- and AGE-positive inclusion bodies by using immunocytochemical, biochemical, and Western blot techniques. Our results show that AGEs promote in vitro cross-linking of alpha-synuclein, that intracellular accumulation of AGEs precedes alpha-synuclein-positive inclusion body formation, and that extracellular AGEs accelerate the process of intracellular alpha-synuclein-positive inclusion body formation.

  9. Modelling multi-phase liquid-sediment scour and resuspension induced by rapid flows using Smoothed Particle Hydrodynamics (SPH) accelerated with a Graphics Processing Unit (GPU)

    NASA Astrophysics Data System (ADS)

    Fourtakas, G.; Rogers, B. D.

    2016-06-01

    A two-phase numerical model using Smoothed Particle Hydrodynamics (SPH) is applied to two-phase liquid-sediments flows. The absence of a mesh in SPH is ideal for interfacial and highly non-linear flows with changing fragmentation of the interface, mixing and resuspension. The rheology of sediment induced under rapid flows undergoes several states which are only partially described by previous research in SPH. This paper attempts to bridge the gap between the geotechnics, non-Newtonian and Newtonian flows by proposing a model that combines the yielding, shear and suspension layer which are needed to predict accurately the global erosion phenomena, from a hydrodynamics prospective. The numerical SPH scheme is based on the explicit treatment of both phases using Newtonian and the non-Newtonian Bingham-type Herschel-Bulkley-Papanastasiou constitutive model. This is supplemented by the Drucker-Prager yield criterion to predict the onset of yielding of the sediment surface and a concentration suspension model. The multi-phase model has been compared with experimental and 2-D reference numerical models for scour following a dry-bed dam break yielding satisfactory results and improvements over well-known SPH multi-phase models. With 3-D simulations requiring a large number of particles, the code is accelerated with a graphics processing unit (GPU) in the open-source DualSPHysics code. The implementation and optimisation of the code achieved a speed up of x58 over an optimised single thread serial code. A 3-D dam break over a non-cohesive erodible bed simulation with over 4 million particles yields close agreement with experimental scour and water surface profiles.

  10. Effects of Cinacalcet on Atherosclerotic and Nonatherosclerotic Cardiovascular Events in Patients Receiving Hemodialysis: The EValuation Of Cinacalcet HCl Therapy to Lower CardioVascular Events (EVOLVE) Trial

    PubMed Central

    Wheeler, David C.; London, Gerard M.; Parfrey, Patrick S.; Block, Geoffrey A.; Correa‐Rotter, Ricardo; Dehmel, Bastian; Drüeke, Tilman B.; Floege, Jürgen; Kubo, Yumi; Mahaffey, Kenneth W.; Goodman, William G.; Moe, Sharon M.; Trotman, Marie‐Louise; Abdalla, Safa; Chertow, Glenn M.; Herzog, Charles A.

    2014-01-01

    Background Premature cardiovascular disease limits the duration and quality of life on long‐term hemodialysis. The objective of this study was to define the frequency of fatal and nonfatal cardiovascular events attributable to atherosclerotic and nonatherosclerotic mechanisms, risk factors for these events, and the effects of cinacalcet, using adjudicated data collected during the EValuation of Cinacalcet HCl Therapy to Lower CardioVascular Events (EVOLVE) Trial. Methods and Results EVOLVE was a randomized, double‐blind, placebo‐controlled clinical trial that randomized 3883 hemodialysis patients with moderate to severe secondary hyperparathyroidism to cinacalcet or matched placebo for up to 64 months. For this post hoc analysis, the outcome measure was fatal and nonfatal cardiovascular events reflecting atherosclerotic and nonatherosclerotic cardiovascular diseases. During the trial, 1518 patients experienced an adjudicated cardiovascular event, including 958 attributable to nonatherosclerotic disease. Of 1421 deaths during the trial, 768 (54%) were due to cardiovascular disease. Sudden death was the most frequent fatal cardiovascular event, accounting for 24.5% of overall mortality. Combining fatal and nonfatal cardiovascular events, randomization to cinacalcet reduced the rates of sudden death and heart failure. Patients randomized to cinacalcet experienced fewer nonatherosclerotic cardiovascular events (adjusted relative hazard 0.84, 95% CI 0.74 to 0.96), while the effect of cinacalcet on atherosclerotic events did not reach statistical significance. Conclusions Accepting the limitations of post hoc analysis, any benefits of cinacalcet on cardiovascular disease in the context of hemodialysis may result from attenuation of nonatherosclerotic processes. Clinical Trials Registration Unique identifier: NCT00345839. URL: ClinicalTrials.gov. PMID:25404192

  11. Neurodegeneration in accelerated aging.

    PubMed

    Scheibye-Knudsen, Moren

    2016-11-01

    The growing proportion of elderly people represents an increasing economic burden, not least because of age-associated diseases that pose a significant cost to the health service. Finding possible interventions to age-associated disorders therefore have wide ranging implications. A number of genetically defined accelerated aging diseases have been characterized that can aid in our understanding of aging. Interestingly, all these diseases are associated with defects in the maintenance of our genome. A subset of these disorders, Cockayne syndrome, Xeroderma pigmentosum group A and ataxia-telangiectasia, show neurological involvement reminiscent of what is seen in primary human mitochondrial diseases. Mitochondria are the power plants of the cells converting energy stored in oxygen, sugar, fat, and protein into ATP, the energetic currency of our body. Emerging evidence has linked this organelle to aging and finding mitochondrial dysfunction in accelerated aging disorders thereby strengthens the mitochondrial theory of aging. This theory states that an accumulation of damage to the mitochondria may underlie the process of aging. Indeed, it appears that some accelerated aging disorders that show neurodegeneration also have mitochondrial dysfunction. The mitochondrial alterations may be secondary to defects in nuclear DNA repair. Indeed, nuclear DNA damage may lead to increased energy consumption, alterations in mitochondrial ATP production and defects in mitochondrial recycling, a term called mitophagy. These changes may be caused by activation of poly-ADP-ribose-polymerase 1 (PARP1), an enzyme that responds to DNA damage. Upon activation PARP1 utilizes key metabolites that attenuate pathways that are normally protective for the cell. Notably, pharmacological inhibition of PARP1 or reconstitution of the metabolites rescues the changes caused by PARP1 hyperactivation and in many cases reverse the phenotypes associated with accelerated aging. This implies that modulation

  12. Menopause accelerates biological aging

    PubMed Central

    Levine, Morgan E.; Lu, Ake T.; Chen, Brian H.; Hernandez, Dena G.; Singleton, Andrew B.; Ferrucci, Luigi; Bandinelli, Stefania; Salfati, Elias; Manson, JoAnn E.; Quach, Austin; Kusters, Cynthia D. J.; Kuh, Diana; Wong, Andrew; Teschendorff, Andrew E.; Widschwendter, Martin; Ritz, Beate R.; Absher, Devin; Assimes, Themistocles L.; Horvath, Steve

    2016-01-01

    Although epigenetic processes have been linked to aging and disease in other systems, it is not yet known whether they relate to reproductive aging. Recently, we developed a highly accurate epigenetic biomarker of age (known as the “epigenetic clock”), which is based on DNA methylation levels. Here we carry out an epigenetic clock analysis of blood, saliva, and buccal epithelium using data from four large studies: the Women's Health Initiative (n = 1,864); Invecchiare nel Chianti (n = 200); Parkinson's disease, Environment, and Genes (n = 256); and the United Kingdom Medical Research Council National Survey of Health and Development (n = 790). We find that increased epigenetic age acceleration in blood is significantly associated with earlier menopause (P = 0.00091), bilateral oophorectomy (P = 0.0018), and a longer time since menopause (P = 0.017). Conversely, epigenetic age acceleration in buccal epithelium and saliva do not relate to age at menopause; however, a higher epigenetic age in saliva is exhibited in women who undergo bilateral oophorectomy (P = 0.0079), while a lower epigenetic age in buccal epithelium was found for women who underwent menopausal hormone therapy (P = 0.00078). Using genetic data, we find evidence of coheritability between age at menopause and epigenetic age acceleration in blood. Using Mendelian randomization analysis, we find that two SNPs that are highly associated with age at menopause exhibit a significant association with epigenetic age acceleration. Overall, our Mendelian randomization approach and other lines of evidence suggest that menopause accelerates epigenetic aging of blood, but mechanistic studies will be needed to dissect cause-and-effect relationships further. PMID:27457926

  13. Introduction to Particle Acceleration in the Cosmos

    NASA Technical Reports Server (NTRS)

    Gallagher, D. L.; Horwitz, J. L.; Perez, J.; Quenby, J.

    2005-01-01

    Accelerated charged particles have been used on Earth since 1930 to explore the very essence of matter, for industrial applications, and for medical treatments. Throughout the universe nature employs a dizzying array of acceleration processes to produce particles spanning twenty orders of magnitude in energy range, while shaping our cosmic environment. Here, we introduce and review the basic physical processes causing particle acceleration, in astrophysical plasmas from geospace to the outer reaches of the cosmos. These processes are chiefly divided into four categories: adiabatic and other forms of non-stochastic acceleration, magnetic energy storage and stochastic acceleration, shock acceleration, and plasma wave and turbulent acceleration. The purpose of this introduction is to set the stage and context for the individual papers comprising this monograph.

  14. Progress on plasma accelerators

    SciTech Connect

    Chen, P.

    1986-05-01

    Several plasma accelerator concepts are reviewed, with emphasis on the Plasma Beat Wave Accelerator (PBWA) and the Plasma Wake Field Accelerator (PWFA). Various accelerator physics issues regarding these schemes are discussed, and numerical examples on laboratory scale experiments are given. The efficiency of plasma accelerators is then revealed with suggestions on improvements. Sources that cause emittance growth are discussed briefly.

  15. Aggregatibacter actinomycetemcomitans induces Th17 cells in atherosclerotic lesions.

    PubMed

    Jia, Ru; Hashizume-Takizawa, Tomomi; Du, Yuan; Yamamoto, Masafumi; Kurita-Ochiai, Tomoko

    2015-04-01

    Th17 cells have been linked to the pathogenesis of several chronic inflammatory and autoimmune diseases. However, the role of Th17 cells and IL-17 in atherosclerosis remains poorly understood. We previously reported that Aggregatibacter actinomycetemcomitans (Aa) bacteremia accelerated atherosclerosis accompanied by inflammation in apolipoprotein E-deficient spontaneously hyperlipidemic (Apoe(shl)) mice. In this study, we investigated whether Aa promotes the Th17 inducing pathway in Aa-challenged Apoe(shl) mice. Mice were intravenously injected with live Aa HK1651 or vehicles. Time-course analysis of splenic IL-17(+)CD4(+) cell frequencies, the proximal aorta lesion area, serum IL-17, IL-6, TGF-β and IL-1β levels, the mRNA expression of Th17-related molecules such as IL-1β, IL-6, IL17RA, STAT3, IL-21, IL-23, TGF-β and RORγt, Th17-related microRNA levels and the levels of AIM-2, Mincle and NLRP3 were examined. Challenge with Aa time dependently induced tropism of Th17 cells in the spleen and increase in atheromatous lesions in the aortic sinus of Apoe(shl) mice. Serum IL-17, IL-6, TGF-β and IL-1β levels were significantly enhanced by Aa. The gene expression of IL-1β, IL-6, IL-17RA, IL-21, IL-23, TGF-β, STAT3, RORγt, AIM-2, Mincle and NLRP3 was also time dependently stimulated in the aorta of Aa-challenged mice. Furthermore, Aa challenge significantly increased the expression of miR-146b and miR-155 in the aorta. Based on the results, it seems that Aa stimulates Th17 induction that affects the progression of Aa-accelerated atherosclerosis.

  16. Wave Detection in Acceleration Plethysmogram

    PubMed Central

    2015-01-01

    Objectives Acceleration plethysmogram (APG) obtained from the second derivative of photoplethysmography (PPG) is used to predict risk factors for atherosclerosis with age. This technique is promising for early screening of atherosclerotic pathologies. However, extraction of the wave indices of APG signals measured from the fingertip is challenging. In this paper, the development of a wave detection algorithm including a preamplifier based on a microcontroller that can detect the a, b, c, and d wave indices is proposed. Methods The 4th order derivative of a PPG under real measurements of an APG waveform was introduced to clearly separate the components of the waveform, and to improve the rate of successful wave detection. A preamplifier with a Sallen-Key low pass filter and a wave detection algorithm with programmable gain control, mathematical differentials, and a digital IIR notch filter were designed. Results The frequency response of the digital IIR filter was evaluated, and a pulse train consisting of a specific area in which the wave indices existed was generated. The programmable gain control maintained a constant APG amplitude at the output for varying PPG amplitudes. For 164 subjects, the mean values and standard deviation of the a wave index corresponding to the magnitude of the APG signal were 1,106.45 and ±47.75, respectively. Conclusions We conclude that the proposed algorithm and preamplifier designed to extract the wave indices of an APG in real-time are useful for evaluating vascular aging in the cardiovascular system in a simple healthcare device. PMID:25995963

  17. Network acceleration techniques

    NASA Technical Reports Server (NTRS)

    Crowley, Patricia (Inventor); Awrach, James Michael (Inventor); Maccabe, Arthur Barney (Inventor)

    2012-01-01

    Splintered offloading techniques with receive batch processing are described for network acceleration. Such techniques offload specific functionality to a NIC while maintaining the bulk of the protocol processing in the host operating system ("OS"). The resulting protocol implementation allows the application to bypass the protocol processing of the received data. Such can be accomplished this by moving data from the NIC directly to the application through direct memory access ("DMA") and batch processing the receive headers in the host OS when the host OS is interrupted to perform other work. Batch processing receive headers allows the data path to be separated from the control path. Unlike operating system bypass, however, the operating system still fully manages the network resource and has relevant feedback about traffic and flows. Embodiments of the present disclosure can therefore address the challenges of networks with extreme bandwidth delay products (BWDP).

  18. Review of accelerator instrumentation

    SciTech Connect

    Pellegrin, J.L.

    1980-05-01

    Some of the problems associated with the monitoring of accelerator beams, particularly storage rings' beams, are reviewed along with their most common solutions. The various electrode structures used for the measurement of beam current, beam position, and the detection of the bunches' transverse oscillations, yield pulses with sub-nanosecond widths. The electronics for the processing of these short pulses involves wide band techniques and circuits usually not readily available from industry or the integrated circuit market: passive or active, successive integrations, linear gating, sample-and-hold circuits with nanosecond acquisition time, etc. This report also presents the work performed recently for monitoring the ultrashort beams of colliding linear accelerators or single-pass colliders. To minimize the beam emittance, the beam position must be measured with a high resolution, and digitized on a pulse-to-pulse basis. Experimental results obtained with the Stanford two-mile Linac single bunches are included.

  19. SUPERDIFFUSIVE SHOCK ACCELERATION

    SciTech Connect

    Perri, S.; Zimbardo, G.

    2012-05-10

    The theory of diffusive shock acceleration is extended to the case of superdiffusive transport, i.e., when the mean square deviation grows proportionally to t{sup {alpha}}, with {alpha} > 1. Superdiffusion can be described by a statistical process called Levy random walk, in which the propagator is not a Gaussian but it exhibits power-law tails. By using the propagator appropriate for Levy random walk, it is found that the indices of energy spectra of particles are harder than those obtained where a normal diffusion is envisaged, with the spectral index decreasing with the increase of {alpha}. A new scaling for the acceleration time is also found, allowing substantially shorter times than in the case of normal diffusion. Within this framework we can explain a number of observations of flat spectra in various astrophysical and heliospheric contexts, for instance, for the Crab Nebula and the termination shock of the solar wind.

  20. Towards the development of an in vitro model of atherosclerotic peripheral vessels for evaluating drug-coated endovascular technologies.

    PubMed

    Cunnane, Eoghan M; Walsh, Michael T

    2016-09-01

    Here, we review the in vitro models used to evaluate drug-coated endovascular technologies. The models are assessed in the context of representing the drug transport/uptake and mechanical properties of atherosclerotic peripheral vessels. Studies to date have incorporated a vessel-simulating hydrogel compartment to examine drug elution from endovascular devices. However, comparisons between in vitro models and atherosclerotic tissue are difficult because ex vivo data are limited in their applicability to diseased peripheral vessels. Furthermore, appropriate ex vivo mechanical properties are not incorporated into these models. Therefore, there is a need to characterise the drug transport/uptake properties of appropriate atherosclerotic tissue and incorporate existing ex vivo mechanical data into current in vitro models to more accurately represent drug behaviour in atherosclerotic peripheral vessels.

  1. David M. Hume memorial lecture. In situ vein bypass in the treatment of femoropopliteal atherosclerotic disease: a ten year study.

    PubMed

    Hall, K V; Rostad, H

    1978-08-01

    The in situ vein bypass technic for femoropopliteal atherosclerotic disease is described. Several factors influence the long-term results, the most important being a history of myocardial disease, the size of the vein graft, and sufficient runoff.

  2. Vacuum Brazing of Accelerator Components

    NASA Astrophysics Data System (ADS)

    Singh, Rajvir; Pant, K. K.; Lal, Shankar; Yadav, D. P.; Garg, S. R.; Raghuvanshi, V. K.; Mundra, G.

    2012-11-01

    Commonly used materials for accelerator components are those which are vacuum compatible and thermally conductive. Stainless steel, aluminum and copper are common among them. Stainless steel is a poor heat conductor and not very common in use where good thermal conductivity is required. Aluminum and copper and their alloys meet the above requirements and are frequently used for the above purpose. The accelerator components made of aluminum and its alloys using welding process have become a common practice now a days. It is mandatory to use copper and its other grades in RF devices required for accelerators. Beam line and Front End components of the accelerators are fabricated from stainless steel and OFHC copper. Fabrication of components made of copper using welding process is very difficult and in most of the cases it is impossible. Fabrication and joining in such cases is possible using brazing process especially under vacuum and inert gas atmosphere. Several accelerator components have been vacuum brazed for Indus projects at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore using vacuum brazing facility available at RRCAT, Indore. This paper presents details regarding development of the above mentioned high value and strategic components/assemblies. It will include basics required for vacuum brazing, details of vacuum brazing facility, joint design, fixturing of the jobs, selection of filler alloys, optimization of brazing parameters so as to obtain high quality brazed joints, brief description of vacuum brazed accelerator components etc.

  3. Older plasma lipoproteins are more susceptible to oxidation: a linking mechanism for the lipid and oxidation theories of atherosclerotic cardiovascular disease.

    PubMed

    Walzem, R L; Watkins, S; Frankel, E N; Hansen, R J; German, J B

    1995-08-01

    Increases in plasma cholesterol are associated with progressive increases in the risk of atherosclerotic cardiovascular disease. In humans plasma cholesterol is contained primarily in apolipoprotein B-based low density lipoprotein (LDL). Cells stop making the high-affinity receptor responsible for LDL removal as they become cholesterol replete; this slows removal of LDL from plasma and elevates plasma LDL. As a result of this delayed uptake, hypercholesterolemic individuals not only have more LDL but have significantly older LDL. Oxidative modification of LDL enhances their atherogenicity. This study sought to determine whether increased time spent in circulation, or aging, by lipoprotein particles altered their susceptibility to oxidative modification. Controlled synchronous production of distinctive apolipoprotein B lipoproteins (yolk-specific very low density lipoproteins; VLDLy) with a single estrogen injection into young turkeys was used to model LDL aging in vivo. VLDLy remained in circulation for at least 10 days. Susceptibility to oxidation in vitro was highly dependent on lipoprotein age in vivo. Oxidation, measured as hexanal release from n-6 fatty acids in VLDLy, increased from 13.3 +/- 5.5 nmol of 2-day-old VLDLy per ml, to 108 +/- 17 nmol of 7-day-old VLDLy per ml. Oxidative instability was not due to tocopherol depletion or conversion to a more unsaturated fatty acid composition. These findings establish mathematically describable linkages between the variables of LDL concentration and LDL oxidation. The proposed mathematical models suggest a unified investigative approach to determine the mechanisms for acceleration of atherosclerotic cardiovascular disease risk as plasma cholesterol rises.

  4. Targeted Delivery of Shear Stress-Inducible Micrornas by Nanoparticles to Prevent Vulnerable Atherosclerotic Lesions

    PubMed Central

    Wong, Wing Tak; Ma, Shuangtao; Tian, Xiao Yu; Gonzalez, Andrea Banuet; Ebong, Eno E.; Shen, Haifa

    2016-01-01

    Atherosclerosis is a chronic inflammatory vascular wall disease, and endothelial cell dysfunction plays an important role in its development and progression. Under the influence of laminar shear stress, however, the endothelium releases homeostatic factors such as nitric oxide and expresses of vasoprotective microRNAs that are resistant to atherosclerosis. Adhesion molecules such as E-selectin, exhibited on the endothelial surface, recruit monocytes that enter the vessel wall to form foam cells. Accumulation of these foam cells form fatty streaks that may progress to atherosclerotic plaques in the blood vessel wall. Interestingly, E-selectin may also serve as an affinity moiety for targeted drug delivery against atherosclerosis. We have recently developed an E-selectin-targeted platform that enriches therapeutic microRNAs in the inflamed endothelium to inhibit formation of vulnerable atherosclerotic plaques. PMID:27826369

  5. The role of near-infrared spectroscopy in the detection of vulnerable atherosclerotic plaques

    PubMed Central

    Hajek, Petr; Stechovsky, Cyril; Honek, Jakub; Spacek, Miloslav; Veselka, Josef

    2016-01-01

    Coronary artery disease is the leading cause of mortality worldwide. Most acute coronary syndromes are caused by a rupture of a vulnerable atherosclerotic plaque which can be characterized by a lipid-rich necrotic core with an overlying thin fibrous cap. Many vulnerable plaques can cause angiographically mild stenoses due to positive remodelling, which is why the extent of coronary artery disease may be seriously underestimated. In recent years, we have witnessed a paradigm shift in interventional cardiology. We no longer focus solely on the degree of stenosis; rather, we seek to determine the true extent of atherosclerotic disease. We seek to identify high-risk plaques for improvement in risk stratification of patients and prevention. Several imaging methods have been developed for this purpose. Intracoronary near-infrared spectroscopy is one of the most promising. Here, we discuss the possible applications of this diagnostic method and provide a comprehensive overview of the current knowledge. PMID:27904523

  6. Cholesterol and prevention of atherosclerotic events: limits of a new frontier

    PubMed Central

    de Macedo, Luís Eduardo Teixeira; Faerstein, E

    2016-01-01

    ABSTRACT Control of atherosclerotic cardiovascular disease – a highly prevalent condition and one of the main causes of mortality in Brazil and worldwide – is a recurrent subject of great interest for public health. Recently, three new guidelines on dyslipidemia and atherosclerosis prevention have been published. The close release of these important publications is a good opportunity for comparison: the Brazilian model has greater sensitivity, the English model does not work with risk stratification, and the American model may be overestimating the risk. This will allow reflection on current progress and identification of controversial aspects which still require further research and debate. It is also an opportunity to discuss issues related to early diagnosis and its efficiency as a preventive strategy for atherosclerotic disease: the transformation of risk into disease, the gradual reduction of cut-off points, the limitations of the screening strategy, and the problem of overdiagnosis. PMID:28099551

  7. [From myocardium to the atherosclerotic plaque: new perspectives in cardiologic imaging].

    PubMed

    Gargiulo, Paola; D'Amore, Carmen; Dellegrottaglie, Santo; Leosco, Dario; Rengo, Giuseppe; Musella, Francesca; Pirozzi, Elisabetta; Mosca, Susanna; Casaretti, Laura; Formisano, Roberto; Bologna, Ada; Parente, Antonio; Conte, Sirio; Perrone-Filardi, Pasquale

    2011-06-01

    Molecular imaging is an innovative and promising approach in cardiology for functional characterization of atherosclerosis. Nuclear, ultrasound and magnetic resonance imaging have been used for assessment of atherosclerosis of large and small arteries in several clinical and experimental studies. Positron Emission Tomography with fluorodeoxyglucose can measure metabolic activity and vulnerability of atherosclerotic plaques, identifying individuals at risk of future cardiovascular events. Magnetic resonance imaging can quantify carotid artery inflammation using iron oxide nanoparticles as contrast agent. In addition, macrophage accumulation of iron particles in atherosclerotic plaques may allow monitoring of inflammation during drug therapy, whereas contrast-enhanced ultrasound imaging may detect plaque neovascularization. Currently, technical factors, including cardiac and diaphragmatic motion and small size of coronary vessels, limit routine application of these techniques for coronary imaging. Purpose of this review is to describe state of the art and potential areas of clinical applications of molecular imaging of atherosclerosis.

  8. Electron Acceleration by Transient Ion Foreshock Phenomena

    NASA Astrophysics Data System (ADS)

    Wilson, L. B., III; Turner, D. L.

    2015-12-01

    Particle acceleration is a topic of considerable interest in space, laboratory, and astrophysical plasmas as it is a fundamental physical process to all areas of physics. Recent THEMIS [e.g., Turner et al., 2014] and Wind [e.g., Wilson et al., 2013] observations have found evidence for strong particle acceleration at macro- and meso-scale structures and/or pulsations called transient ion foreshock phenomena (TIFP). Ion acceleration has been extensively studied, but electron acceleration has received less attention. Electron acceleration can arise from fundamentally different processes than those affecting ions due to differences in their gyroradii. Electron acceleration is ubiquitous, occurring in the solar corona (e.g., solar flares), magnetic reconnection, at shocks, astrophysical plasmas, etc. We present new results analyzing the dependencies of electron acceleration on the properties of TIFP observed by the THEMIS spacecraft.

  9. Association of Thrombomodulin Gene Polymorphisms with Susceptibility to Atherosclerotic Diseases: A Meta-Analysis.

    PubMed

    Xu, Jie; Jin, Jun; Tan, Sheng

    2016-05-01

    Previous studies have proved that the dysfunction of thrombomodulin (TM) plays an important role in the pathogenesis of atherosclerotic diseases. In order to reveal their inherent relationship, we conducted a meta-analysis to uncover the association between two polymorphisms -33G/A and Ala455Val (c.1418C>T) in the TM gene and atherosclerotic diseases. We carried out a systematic search in PubMed, Science Direct, BIOSIS Previews, SpringerLink, the Cochrane library, the Chinese National Knowledge Infrastructure, the Chinese Biomedical Database, the Wei Pu database, and the Wanfang Database. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were computed to show the association. We included 22 eligible studies which involved 5472 patients and 7786 controls. There were statistically significant associations between -33G/A polymorphisms in TM and the MI group under the Allele and Recessive models in Asians (G vs. A: OR = 0.67, 95%CI = 0.56-0.78, P < 0.00001; GG vs. GA+AA: OR = 0.66, 95%CI = 0.56-0.78, P < 0.00001). However, these findings of the overall and subgroups showed that Ala455Val polymorphisms did not have any relationship with atherosclerotic diseases. After Bonferroni correction, the above associations remained statistically significant. This meta-analysis provides robust evidence of association between the -33G/A polymorphism in the TM gene and the risk of myocardial infarction in Asians. The A allele may increase the incidence of MI in Asians. However, the Ala455Val variant was not associated with atherosclerotic risk. Further studies with adequate sample size are needed to verify our findings.

  10. Intravascular electric impedance spectroscopy of atherosclerotic lesions using a new impedance catheter system.

    PubMed

    Süselbeck, T; Thielecke, H; Köchlin, J; Cho, S; Weinschenk, I; Metz, J; Borggrefe, M; Haase, K K

    2005-09-01

    Newer techniques are required to identify atherosclerotic lesions that are prone to rupture. Electric impedance spectroscopy (EIS) can characterize biological tissues by measuring the electrical impedance over a frequency range. We tested a newly designed intravascular impedance catheter (IC) by measuring the impedance of different stages of atherosclerosis induced in an animal rabbit model. Six female New Zealand White rabbits were fed for 17 weeks with a 5% cholesterol-enriched diet to induce early forms of atherosclerotic plaques. All aortas were prepared from the aortic arch to the renal arteries and segments of 5-10 mm were marked by ink spots. A balloon catheter system with an integrated polyimide-based microelectrode structure was introduced into the aorta and the impedance was measured at each spot by using an impedance analyzer. The impedance was measured at frequencies of 1 kHz and 10 kHz and compared with the corresponding histomorphometric data of each aortic segment.Forty-four aortic segments without plaques and 48 segments with evolving atherosclerotic lesions could be exactly matched by the histomorphometric analysis. In normal aortic segments (P0) the change of the magnitude of impedance at 1 kHz and at 10 kHz (|Z|(1 kHz) - |Z|(10 kHz), = ICF) was 208.5 +/- 357.6 Omega. In the area of aortic segments with a plaque smaller than that of the aortic wall diameter (PI), the ICF was 137.7 +/- 192.8 Omega. (P 0 vs. P I; p = 0.52), whereas in aortic segments with plaque formations larger than the aortic wall (PII) the ICF was significantly lower -22.2 +/- 259.9 Omega. (P0 vs. PII; p = 0.002). Intravascular EIS could be successfully performed by using a newly designed microelectrode integrated onto a conventional coronary balloon catheter. In this experimental animal model atherosclerotic aortic lesions showed significantly higher ICF in comparison to the normal aortic tissue.

  11. Medical and Surgical Management of a Descending Aorta Penetrating Atherosclerotic Ulcer and Associated Ascending Intramural Hematoma

    PubMed Central

    Henn, Matthew C.; Lawrance, Christopher P.; Braverman, Alan C.; Sanchez, Luis; Lawton, Jennifer S.

    2014-01-01

    A 69-year-old man presented with chest pain and a computed tomography scan demonstrated an acute penetrating atherosclerotic ulcer (PAU) of the proximal descending aorta with an associated intramural hematoma (IMH) extending retrograde to the aortic root and distally to the renal arteries. He successfully underwent endovascular repair of the PAU and medical management of the associated ascending intramural hematoma with complete resolution at 6 months. PMID:26798718

  12. Reduction in atherosclerotic events: a retrospective study in an outpatient cardiology practice

    PubMed Central

    Mercando, Anthony D.; Lai, Hoang M.; Kalen, Phoenix; Desai, Harit V.; Gandhi, Kaushang; Sharma, Mala; Amin, Harshad; Lai, Trung M.

    2012-01-01

    Introduction Although atherosclerotic disease cannot be cured, risk of recurrent events can be reduced by application of evidence-based treatment protocols involving aspirin, beta blockers, angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, and statin medications. We studied atherosclerotic event rates in a patient population treated before and after the development of aggressive risk factor reduction treatment protocols. Material and methods We performed a retrospective chart review of patients presenting for follow-up treatment of coronary artery disease in a community cardiology practice, comparing atherosclerotic event rates and medication usage in a 2-year treatment period prior to 2002 and a 2-year period in 2005-2008. Care was provided in both the early and later eras by 7 board-certified cardiologists in a suburban cardiology practice. Medication usage was compared in both treatment eras. The primary outcome was a composite event rate of myocardial infarction, cerebrovascular events, and coronary interventions. Results Three hundred and fifty-seven patients were studied, with a follow-up duration of 12.1 (±3.5) years. There were 132 composite events in 104 patients (29.1%) in the early era compared to 40 events in 33 patients (9.2%) in the later era (p < 0.0001). From the early to the later eras, there was an increase in use of β-blockers (66% to 83%, p < 0.0001), angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (34% to 80%, p < 0.0001), and statins (40% to 90%, p < 0.0001). Conclusions Application of aggressive evidence-based medication protocols for treatment of atherosclerosis is associated with a significant decrease in atherosclerotic events or need for coronary intervention. PMID:22457676

  13. Selepressin and Arginine Vasopressin Do Not Display Cardiovascular Risk in Atherosclerotic Rabbit

    PubMed Central

    Boucheix, Olivier; Blakytny, Robert; Haroutunian, Gerard; Henriksson, Marie; Laporte, Regent; Milano, Stephane; Reinheimer, Torsten M.

    2016-01-01

    Background Septic shock remains associated with significant mortality rates. Arginine vasopressin (AVP) and analogs with V1A receptor agonist activity are increasingly used to treat fluid-resistant vasodilatory hypotension, including catecholamine-refractory septic shock. Clinical studies have been restricted to healthy volunteers and catecholamine-refractory septic shock patients excluding subjects with cardiac co-morbidities because of presumed safety issues. The novel selective V1A receptor agonist selepressin, with short half-life, has been designed to avoid V2 receptor-related complications and long-term V1A receptor activation. Cardiovascular safety of selepressin, AVP, and the septic shock standard of care norepinephrine was investigated in a rabbit model of early-stage atherosclerosis. Methods Atherosclerosis was established in New Zealand White rabbits using a 1% cholesterol-containing diet. Selepressin, AVP, or norepinephrine was administered as cumulative intravenous infusion rates to atherosclerotic and non-atherosclerotic animals. Results Selepressin and AVP induced a slight dose-dependent increase in arterial pressure (AP) associated with a moderate decrease in heart rate, no change in stroke volume, and a moderate decrease in aortic blood flow (ABF). In contrast, norepinephrine induced a marked dose-dependent increase in AP associated with a lesser decrease in the heart rate, an increase in stroke volume, and a moderate increase in ABF. For all three vasopressors, there was no difference in responses between atherosclerotic and non-atherosclerotic animals. Conclusion Further studies should be considered using more advanced atherosclerosis models, including with septic shock, before considering septic shock clinical trials of patients with comorbidities. Here, selepressin and AVP treatments did not display relevant cardiovascular risk in early-stage rabbit atherosclerosis. PMID:27788216

  14. IL-35 improves Treg-mediated immune suppression in atherosclerotic mice

    PubMed Central

    Tao, Linlin; Zhu, Jie; Chen, Yuefeng; Wang, Qinghang; Pan, Ying; Yu, Qianqian; Zhou, Birong; Zhu, Huaqing

    2016-01-01

    Interleukin (IL)-35 is an anti-inflammatory cytokine that may have a protective role in atherosclerosis (AS). However, the exact role of IL-35 in the disease, and the etiology of AS, remain incompletely understood. The present study aimed to investigate whether exogenous IL-35 was able to attenuate the formation of atherosclerotic lesions in apoE−/− mice, and analyze alterations in the expression levels of forkhead box protein 3 (Foxp3) in peripheral blood and the lesions during the progression of AS. ApoE−/− mice were randomly divided into two groups that received either a basal diet (negative control group) or a high-fat diet (HFD) for 4 weeks. The HFD group was further subdivided into groups that received IL-35, atorvastatin or no treatment for 12 weeks. Diagnostic enzyme assay kits were applied for the detection of plasma lipids, and hematoxylin and eosin staining was used to analyze the severity of atherosclerotic lesions in apoE−/− mice. Immunohistochemistry and flow cytometry were performed to analyze the expression of Foxp3 in the plasma and atherosclerotic plaques. As compared with the negative control group, the plasma lipids were significantly increased, and the lesions were obviously formed, in the HFD groups. Furthermore, the area of the lesion was reduced in IL-35- and atorvastatin-treated groups, as compared with the AS control group. In addition, Foxp3 expression was upregulated in the plasma and lesions of the IL-35- and atorvastatin-treated groups, as compared with the AS control group. The present study demonstrated that IL-35 improved Treg-mediated immune suppression in atherosclerotic mice, thus suggesting that IL-35 may be a novel therapeutic target for AS. PMID:27698748

  15. Simulation of human atherosclerotic femoral plaque tissue: the influence of plaque material model on numerical results

    PubMed Central

    2015-01-01

    Background Due to the limited number of experimental studies that mechanically characterise human atherosclerotic plaque tissue from the femoral arteries, a recent trend has emerged in current literature whereby one set of material data based on aortic plaque tissue is employed to numerically represent diseased femoral artery tissue. This study aims to generate novel vessel-appropriate material models for femoral plaque tissue and assess the influence of using material models based on experimental data generated from aortic plaque testing to represent diseased femoral arterial tissue. Methods Novel material models based on experimental data generated from testing of atherosclerotic femoral artery tissue are developed and a computational analysis of the revascularisation of a quarter model idealised diseased femoral artery from a 90% diameter stenosis to a 10% diameter stenosis is performed using these novel material models. The simulation is also performed using material models based on experimental data obtained from aortic plaque testing in order to examine the effect of employing vessel appropriate material models versus those currently employed in literature to represent femoral plaque tissue. Results Simulations that employ material models based on atherosclerotic aortic tissue exhibit much higher maximum principal stresses within the plaque than simulations that employ material models based on atherosclerotic femoral tissue. Specifically, employing a material model based on calcified aortic tissue, instead of one based on heavily calcified femoral tissue, to represent diseased femoral arterial vessels results in a 487 fold increase in maximum principal stress within the plaque at a depth of 0.8 mm from the lumen. Conclusions Large differences are induced on numerical results as a consequence of employing material models based on aortic plaque, in place of material models based on femoral plaque, to represent a diseased femoral vessel. Due to these large

  16. Advances in immune-modulating therapies to treat atherosclerotic cardiovascular diseases.

    PubMed

    Chyu, Kuang-Yuh; Shah, Prediman K

    2014-03-01

    In addition to hypercholesterolemia, innate and adaptive immune mechanisms play a critical role in atherogenesis, thus making immune-modulation therapy a potentially attractive way of managing atherosclerotic cardiovascular disease. These immune-modulation strategies include both active and passive immunization and confer beneficial reduction in atherosclerosis. Preclinical studies have demonstrated promising results and we review current knowledge on the complex role of the immune system and the potential for immunization as an immune-modulation therapy for atherosclerosis.

  17. Caspase-3 Deletion Promotes Necrosis in Atherosclerotic Plaques of ApoE Knockout Mice

    PubMed Central

    Schrijvers, Dorien M.; Hermans, Marthe; Van Hoof, Viviane O.; De Meyer, Guido R. Y.

    2016-01-01

    Apoptosis of macrophages and vascular smooth muscle cells (VSMCs) in advanced atherosclerotic plaques contributes to plaque progression and instability. Caspase-3, a key executioner protease in the apoptotic pathway, has been identified in human and mouse atherosclerotic plaques but its role in atherogenesis is not fully explored. We therefore investigated the impact of caspase-3 deletion on atherosclerosis by crossbreeding caspase-3 knockout (Casp3−/−) mice with apolipoprotein E knockout (ApoE−/−) mice. Bone marrow-derived macrophages and VSMCs isolated from Casp3−/−ApoE−/− mice were resistant to apoptosis but showed increased susceptibility to necrosis. However, caspase-3 deficiency did not sensitize cells to undergo RIP1-dependent necroptosis. To study the effect on atherosclerotic plaque development, Casp3+/+ApoE−/− and Casp3−/−ApoE−/− mice were fed a western-type diet for 16 weeks. Though total plasma cholesterol, triglycerides, and LDL cholesterol levels were not altered, both the plaque size and percentage necrosis were significantly increased in the aortic root of Casp3−/−ApoE−/− mice as compared to Casp3+/+ApoE−/− mice. Macrophage content was significantly decreased in plaques of Casp3−/−ApoE−/− mice as compared to controls, while collagen content and VSMC content were not changed. To conclude, deletion of caspase-3 promotes plaque growth and plaque necrosis in ApoE−/− mice, indicating that this antiapoptotic strategy is unfavorable to improve atherosclerotic plaque stability. PMID:27847551

  18. Relationship between vascular endothelium and periodontal disease in atherosclerotic lesions: Review article

    PubMed Central

    Saffi, Marco Aurélio Lumertz; Furtado, Mariana Vargas; Polanczyk, Carisi Anne; Montenegro, Márlon Munhoz; Ribeiro, Ingrid Webb Josephson; Kampits, Cassio; Haas, Alex Nogueira; Rösing, Cassiano Kuchenbecker; Rabelo-Silva, Eneida Rejane

    2015-01-01

    Inflammation and endothelial dysfunction are linked to the pathogenesis of atherosclerotic disease. Recent studies suggest that periodontal infection and the ensuing increase in the levels of inflammatory markers may be associated with myocardial infarction, peripheral vascular disease and cerebrovascular disease. The present article aimed at reviewing contemporary data on the pathophysiology of vascular endothelium and its association with periodontitis in the scenario of cardiovascular disease. PMID:25632316

  19. Acceleration during magnetic reconnection

    SciTech Connect

    Beresnyak, Andrey; Li, Hui

    2015-07-16

    The presentation begins with colorful depictions of solar x-ray flares and references to pulsar phenomena. Plasma reconnection is complex, could be x-point dominated or turbulent, field lines could break due to either resistivity or non-ideal effects, such as electron pressure anisotropy. Electron acceleration is sometimes observed, and sometimes not. One way to study this complex problem is to have many examples of the process (reconnection) and compare them; the other way is to simplify and come to something robust. Ideal MHD (E=0) turbulence driven by magnetic energy is assumed, and the first-order acceleration is sought. It is found that dissipation in big (length >100 ion skin depths) current sheets is universal and independent on microscopic resistivity and the mean imposed field; particles are regularly accelerated while experiencing curvature drift in flows driven by magnetic tension. One example of such flow is spontaneous reconnection. This explains hot electrons with a power-law tail in solar flares, as well as ultrashort time variability in some astrophysical sources.

  20. Space Experiments with Particle Accelerators (SEPAC)

    NASA Technical Reports Server (NTRS)

    Roberts, W. T.

    1985-01-01

    The space experiments with particle accelerators (SEPAC) instruments consist of an electron accelerator, a plasma accelerator, a neutral gas (N2) release device, particle and field diagnostic instruments, and a low light level television system. These instruments are used to accomplish multiple experiments: to study beam particle interactions and other plasma processes; as probes to investigate magnetospheric processes; and as perturbation devices to study energy coupling mechanisms in the magnetosphere, ionosphere, and upper atmosphere.

  1. High-Density Lipoprotein Mimetics: a Therapeutic Tool for Atherosclerotic Diseases.

    PubMed

    Ikenaga, Masahiro; Higaki, Yasuki; Saku, Keijiro; Uehara, Yoshinari

    2016-01-01

    Clinical trials and epidemiological studies have revealed a negative correlation between serum high-density lipoprotein (HDL) cholesterol levels and the risk of cardiovascular events. Currently, statin treatment is the standard therapy for cardiovascular diseases, reducing plasma low-density lipoprotein (LDL) cholesterol levels. However, more than half of the patients have not been able to receive the beneficial effects of this treatment.The reverse cholesterol transport pathway has several potential anti-atherogenic properties. An important approach to HDL-targeted therapy is the optimization of HDL cholesterol levels and function in the blood to enhance the removal of circulating cholesterol and to prevent or mitigate inflammation that causes atherosclerosis. Cholesteryl ester transfer protein inhibitors increase HDL cholesterol levels in humans, but whether they reduce the risk of atherosclerotic diseases is unknown. HDL therapies using HDL mimetics, including reconstituted HDL, apolipoprotein (Apo) A-IMilano, ApoA-I mimetic peptides, or full-length ApoA-I, are highly effective in animal models. In particular, the Fukuoka University ApoA-I-mimetic peptide (FAMP) effectively removes cholesterol via the ABCA1 transporter and acts as an anti-atherosclerotic agent by enhancing the biological functions of HDL without elevating HDL cholesterol levels.Our literature review suggests that HDL mimetics have significant atheroprotective potential and are a therapeutic tool for atherosclerotic diseases.

  2. Laser-induced fluorescence: quantitative analysis of atherosclerotic plaque chemical content in human aorta

    NASA Astrophysics Data System (ADS)

    Dai, Erbin; Wishart, David; Khoury, Samir; Kay, Cyril M.; Jugdutt, Bodh I.; Tulip, John; Lucas, Alexandra

    1996-05-01

    We have been studying laser-induced fluorescence as a technique for identification of selected changes in the chemical composition of atherosclerotic plaque. Formulae for quantification of chemical changes have been developed based upon analysis of fluorescence emission spectra using multiple regression analysis and the principal of least squares. The intima of human aortic necropsy specimens was injected with chemical compounds present in atherosclerotic plaque. Spectra recorded after injection of selected chemical components found in plaque (collagen I, III, IV, elastin and cholesterol) at varying concentrations (0.01 - 1.0 mg) were compared with saline injection. A single fiber system was used for both fluorescence excitation (XeCl excimer laser, 308 nm, 1.5 - 2.0 mJ/ pulse, 5 Hz) and fluorescence emission detection. Average spectra for each chemical have been developed and the wavelengths of peak emission intensity identified. Curve fitting analysis as well as multiple regression analysis were used to develop formulae for assessment of chemical content. Distinctive identifying average curves were established for each chemical. Excellent correlations were identified for collagen I, III, and IV, elastin, and cholesterol (R2 equals 0.92 6- 0.997). Conclusions: (1) Fluorescence spectra of human aortas were significantly altered by collagen I, collagen III, elastin and cholesterol. (2) Fluorescence spectroscopic analysis may allow quantitative assessment of atherosclerotic plaque chemical content in situ.

  3. Regression of atherosclerotic lesions by high density lipoprotein plasma fraction in the cholesterol-fed rabbit.

    PubMed

    Badimon, J J; Badimon, L; Fuster, V

    1990-04-01

    The effects of homologous plasma HDL and VHDL fractions on established atherosclerotic lesions were studied in cholesterol-fed rabbits. Atherosclerosis was induced by feeding the animals a 0.5% cholesterol-rich diet for 60 d (group 1). Another group of animals were maintained on the same diet for 90 d (group 2). A third group was also fed the same diet for 90 d but received 50 mg HDL-VHDL protein per wk (isolated from normolipemic rabbit plasma) during the last 30 d (group 3). Aortic atherosclerotic involvement at the completion of the study was 34 +/- 4% in group 1, 38.8 +/- 5% in group 2, and 17.8 +/- 4% in group 3 (P less than 0.005). Aortic lipid deposition was also significantly reduced in group 3 compared with group 1 (studied at only 60 d) and group 2. This is the first in vivo, prospective evidence of the antiatherogenic effect of HDL-VHDL against preexisting atherosclerosis. Our results showed that HDL plasma fractions were able to induce regression of established aortic fatty streaks and lipid deposits. Our results suggest that it may be possible not only to inhibit progression but even to reduce established atherosclerotic lesions by HDL administration.

  4. A statin-loaded reconstituted high-density lipoprotein nanoparticle inhibits atherosclerotic plaque inflammation

    NASA Astrophysics Data System (ADS)

    Duivenvoorden, Raphaël; Tang, Jun; Cormode, David P.; Mieszawska, Aneta J.; Izquierdo-Garcia, David; Ozcan, Canturk; Otten, Maarten J.; Zaidi, Neeha; Lobatto, Mark E.; van Rijs, Sarian M.; Priem, Bram; Kuan, Emma L.; Martel, Catherine; Hewing, Bernd; Sager, Hendrik; Nahrendorf, Matthias; Randolph, Gwendalyn J.; Stroes, Erik S. G.; Fuster, Valentin; Fisher, Edward A.; Fayad, Zahi A.; Mulder, Willem J. M.

    2014-01-01

    Inflammation is a key feature of atherosclerosis and a target for therapy. Statins have potent anti-inflammatory properties but these cannot be fully exploited with oral statin therapy due to low systemic bioavailability. Here we present an injectable reconstituted high-density lipoprotein (rHDL) nanoparticle carrier vehicle that delivers statins to atherosclerotic plaques. We demonstrate the anti-inflammatory effect of statin-rHDL in vitro and show that this effect is mediated through the inhibition of the mevalonate pathway. We also apply statin-rHDL nanoparticles in vivo in an apolipoprotein E-knockout mouse model of atherosclerosis and show that they accumulate in atherosclerotic lesions in which they directly affect plaque macrophages. Finally, we demonstrate that a 3-month low-dose statin-rHDL treatment regimen inhibits plaque inflammation progression, while a 1-week high-dose regimen markedly decreases inflammation in advanced atherosclerotic plaques. Statin-rHDL represents a novel potent atherosclerosis nanotherapy that directly affects plaque inflammation.

  5. Ex vivo differential phase contrast and magnetic resonance imaging for characterization of human carotid atherosclerotic plaques.

    PubMed

    Meletta, Romana; Borel, Nicole; Stolzmann, Paul; Astolfo, Alberto; Klohs, Jan; Stampanoni, Marco; Rudin, Markus; Schibli, Roger; Krämer, Stefanie D; Herde, Adrienne Müller

    2015-10-01

    Non-invasive detection of specific atherosclerotic plaque components related to vulnerability is of high clinical relevance to prevent cerebrovascular events. The feasibility of magnetic resonance imaging (MRI) for characterization of plaque components was already demonstrated. We aimed to evaluate the potential of ex vivo differential phase contrast X-ray tomography (DPC) to accurately characterize human carotid plaque components in comparison to high field multicontrast MRI and histopathology. Two human plaque segments, obtained from carotid endarterectomy, classified according to criteria of the American Heart Association as stable and unstable plaque, were examined by ex vivo DPC tomography and multicontrast MRI (T1-, T2-, and proton density-weighted imaging, magnetization transfer contrast, diffusion-weighted imaging). To identify specific plaque components, the plaques were subsequently sectioned and stained for fibrous and cellular components, smooth muscle cells, hemosiderin, and fibrin. Histological data were then matched with DPC and MR images to define signal criteria for atherosclerotic plaque components. Characteristic structures, such as the lipid and necrotic core covered by a fibrous cap, calcification and hemosiderin deposits were delineated by histology and found with excellent sensitivity, resolution and accuracy in both imaging modalities. DPC tomography was superior to MRI regarding resolution and soft tissue contrast. Ex vivo DPC tomography allowed accurate identification of structures and components of atherosclerotic plaques at different lesion stages, in good correlation with histopathological findings.

  6. A Statin-Loaded Reconstituted High-Density Lipoprotein Nanoparticle Inhibits Atherosclerotic Plaque Inflammation

    PubMed Central

    Duivenvoorden, Raphaël; Tang, Jun; Cormode, David P.; Mieszawska, Aneta J.; Izquierdo-Garcia, David; Ozcan, Canturk; Otten, Maarten J.; Zaidi, Neeha; Lobatto, Mark E.; van Rijs, Sarian M.; Priem, Bram; Kuan, Emma L.; Martel, Catherine; Hewing, Bernd; Sager, Hendrik; Nahrendorf, Matthias; Randolph, Gwendalyn J.; Stroes, Erik S.G.; Fuster, Valentin; Fisher, Edward A.; Fayad, Zahi A.; Mulder, Willem J.M.

    2014-01-01

    Inflammation is a key feature of atherosclerosis and a target for therapy. Statins have potent anti-inflammatory properties but these cannot be fully exploited with oral statin therapy due to low systemic bioavailability. Here we present an injectable reconstituted high-density lipoprotein (rHDL) nanoparticle carrier vehicle that delivers statins to atherosclerotic plaques. We demonstrate the anti-inflammatory effect of statin-rHDL in vitro and show this effect is mediated through inhibition of the mevalonate pathway. We also apply statin-rHDL nanoparticles in vivo in an apolipoprotein E-knockout mouse model of atherosclerosis and show they accumulate in atherosclerotic lesions where they directly affect plaque macrophages. Finally we demonstrate that a three-month low-dose statin-rHDL treatment regimen inhibits plaque inflammation progression, while a one-week high-dose regimen markedly decreases inflammation in advanced atherosclerotic plaques. Statin-rHDL represents a novel potent atherosclerosis nanotherapy that directly affects plaque inflammation. PMID:24445279

  7. A statin-loaded reconstituted high-density lipoprotein nanoparticle inhibits atherosclerotic plaque inflammation.

    PubMed

    Duivenvoorden, Raphaël; Tang, Jun; Cormode, David P; Mieszawska, Aneta J; Izquierdo-Garcia, David; Ozcan, Canturk; Otten, Maarten J; Zaidi, Neeha; Lobatto, Mark E; van Rijs, Sarian M; Priem, Bram; Kuan, Emma L; Martel, Catherine; Hewing, Bernd; Sager, Hendrik; Nahrendorf, Matthias; Randolph, Gwendalyn J; Stroes, Erik S G; Fuster, Valentin; Fisher, Edward A; Fayad, Zahi A; Mulder, Willem J M

    2014-01-01

    Inflammation is a key feature of atherosclerosis and a target for therapy. Statins have potent anti-inflammatory properties but these cannot be fully exploited with oral statin therapy due to low systemic bioavailability. Here we present an injectable reconstituted high-density lipoprotein (rHDL) nanoparticle carrier vehicle that delivers statins to atherosclerotic plaques. We demonstrate the anti-inflammatory effect of statin-rHDL in vitro and show that this effect is mediated through the inhibition of the mevalonate pathway. We also apply statin-rHDL nanoparticles in vivo in an apolipoprotein E-knockout mouse model of atherosclerosis and show that they accumulate in atherosclerotic lesions in which they directly affect plaque macrophages. Finally, we demonstrate that a 3-month low-dose statin-rHDL treatment regimen inhibits plaque inflammation progression, while a 1-week high-dose regimen markedly decreases inflammation in advanced atherosclerotic plaques. Statin-rHDL represents a novel potent atherosclerosis nanotherapy that directly affects plaque inflammation.

  8. Anti-atherosclerotic and anti-inflammatory actions of sesame oil.

    PubMed

    Narasimhulu, Chandrakala Aluganti; Selvarajan, Krithika; Litvinov, Dmitry; Parthasarathy, Sampath

    2015-01-01

    Atherosclerosis, a major form of cardiovascular disease, has now been recognized as a chronic inflammatory disease. Nonpharmacological means of treating chronic diseases have gained attention recently. We previously reported that sesame oil has anti-atherosclerotic properties. In this study, we have determined the mechanisms by which sesame oil might modulate atherosclerosis by identifying genes and inflammatory markers. Low-density lipoprotein receptor knockout (LDLR(-/-)) female mice were fed with either an atherogenic diet or an atherogenic diet reformulated with sesame oil (sesame oil diet). Plasma lipids and atherosclerotic lesions were quantified after 3 months of feeding. Plasma samples were used for cytokine analysis. RNA was extracted from the liver tissue and used for global gene arrays. The sesame oil diet significantly reduced atherosclerotic lesions, plasma cholesterol, triglyceride, and LDL cholesterol levels in LDLR(-/-) mice. Plasma inflammatory cytokines, such as MCP-1, RANTES, IL-1α, IL-6, and CXCL-16, were significantly reduced, demonstrating an anti-inflammatory property of sesame oil. Gene array analysis showed that sesame oil induced many genes, including ABCA1, ABCA2, APOE, LCAT, and CYP7A1, which are involved in cholesterol metabolism and reverse cholesterol transport. In conclusion, our studies suggest that a sesame oil-enriched diet could be an effective nonpharmacological treatment for atherosclerosis by controlling inflammation and regulating lipid metabolism.

  9. Ex vivo detection of macrophages in atherosclerotic plaques using intravascular ultrasonic-photoacoustic imaging

    NASA Astrophysics Data System (ADS)

    Quang Bui, Nhat; Hlaing, Kyu Kyu; Lee, Yong Wook; Kang, Hyun Wook; Oh, Junghwan

    2017-01-01

    Macrophages are excellent imaging targets for detecting atherosclerotic plaques as they are involved in all the developmental stages of atherosclerosis. However, no imaging technique is currently capable of visualizing macrophages inside blood vessel walls. The current study develops an intravascular ultrasonic-photoacoustic (IVUP) imaging system combined with indocyanine green (ICG) as a contrast agent to provide morphological and compositional information about the targeted samples. Both tissue-mimicking vessel phantoms and atherosclerotic plaque-mimicking porcine arterial tissues are used to demonstrate the feasibility of mapping macrophages labeled with ICG by endoscopically applying the proposed hybrid technique. A delay pulse triggering technique is able to sequentially acquire photoacoustic (PA) and ultrasound (US) signals from a single scan without using any external devices. The acquired PA and US signals are used to reconstruct 2D cross-sectional and 3D volumetric images of the entire tissue with the ICG-loaded macrophages injected. Due to high imaging contrast and sensitivity, the IVUP imaging vividly reveals structural information and detects the spatial distribution of the ICG-labeled macrophages inside the samples. ICG-assisted IVUP imaging can be a feasible imaging modality for the endoscopic detection of atherosclerotic plaques.

  10. Lipoprotein lipase is synthesized by macrophage-derived foam cells in human coronary atherosclerotic plaques.

    PubMed Central

    O'Brien, K D; Gordon, D; Deeb, S; Ferguson, M; Chait, A

    1992-01-01

    Lipoprotein lipase (LPL), hydrolyzes the core triglycerides of lipoproteins, thereby playing a role in their maturation. LPL may be important in the metabolic pathways that lead to atherosclerosis, since it is secreted in vitro by both of the predominant cell types of the atherosclerotic plaque, i.e., macrophages and smooth muscle cells. Because of uncertainty concerning the primary cellular source of LPL in atherosclerotic lesions, in situ hybridization assays for LPL mRNA were performed on 12 coronary arteries obtained from six cardiac allograft recipients. Macrophages and smooth muscle cells were identified on adjacent sections with cell-specific antibodies and foam cells were identified morphologically. LPL protein was localized using a polyclonal antibody. LPL mRNA was produced by a proportion of plaque macrophages, particularly macrophage-derived foam cells, but was not detected in association with any intimal or medial smooth muscle cells. These findings were confirmed by combined immunocytochemistry and in situ hybridization on the same tissue sections. LPL protein was detected in association with macrophage-derived foam cells, endothelial cells, adventitial adipocytes, and medial smooth muscle cells, and, to a lesser extent, in intimal smooth muscle cells and media underlying well-developed plaque. These results indicate that macrophage-derived foam cells are the primary source of LPL in atherosclerotic plaques and are consistent with a role for LPL in the pathogenesis of atherosclerosis. Images PMID:1569193

  11. Myeloperoxidase, a catalyst for lipoprotein oxidation, is expressed in human atherosclerotic lesions.

    PubMed Central

    Daugherty, A; Dunn, J L; Rateri, D L; Heinecke, J W

    1994-01-01

    Oxidatively modified lipoproteins have been implicated in atherogenesis, but the mechanisms that promote oxidation in vivo have not been identified. Myeloperoxidase, a heme protein secreted by activated macrophages, generates reactive intermediates that oxidize lipoproteins in vitro. To explore the potential role of myeloperoxidase in the development of atherosclerosis, we determined whether the enzyme was present in surgically excised human vascular tissue. In detergent extracts of atherosclerotic arteries subjected to Western blotting, a rabbit polyclonal antibody monospecific for myeloperoxidase detected a 56-kD protein, the predicted molecular mass of the heavy subunit. Both the immunoreactive protein and authentic myeloperoxidase bound to a lectin-affinity column; after elution with methyl mannoside their apparent molecular masses were indistinguishable by nondenaturing size-exclusion chromatography. Peroxidase activity in detergent extracts of atherosclerotic lesions likewise bound to a lectin column and eluted with methyl mannoside. Moreover, eluted peroxidase generated the cytotoxic oxidant hypochlorous acid (HOCl), indicating that enzymatically active myeloperoxidase was present in lesions. Patterns of immunostaining of arterial tissue with antihuman myeloperoxidase antibodies were similar to those produced by an antimacrophage antibody, and were especially prominent in the shoulder region of transitional lesions. Intense foci of myeloperoxidase immunostaining also appeared adjacent to cholesterol clefts in lipid-rich regions of advanced atherosclerotic lesions. These findings identify myeloperoxidase as a component of human vascular lesions. Because this heme protein can generate reactive species that damage lipids and proteins, myeloperoxidase may contribute to atherogenesis by catalyzing oxidative reactions in the vascular wall. Images PMID:8040285

  12. Outcome of intracranial arterial stenting of symptomatic atherosclerotic disease: A single center experience from Saudi Arabia

    PubMed Central

    Said, Youssef Al; Kurdi, Khalil; Baeesa, Saleh S.; Najjar, Ahmed; Almekhlafi, Mohammed; Hassan, Ahmed

    2016-01-01

    Objectives: To present our local experience with intracranial angioplasty and stenting used for the treatment of symptomatic intracranial stenosis to assess its safety, efficacy, and outcome. Methods: This is a retrospective review of all the patients with symptomatic intracranial atherosclerotic disease who underwent endovascular treatment in King Faisal Specialist Hospital and research center, Jeddah, Kingdom of Saudi Arabia from January 2003 to December 2014. Clinical, procedural, and outcome variables were gathered. Results: We identified 22 patients who were referred for stenting of symptomatic intracranial atherosclerotic stenosis. In all but 3, the stents were deployed successfully (86% procedural success rate). The procedure was carried out under conscious sedation in 32%. Excellent flow was restored immediately in all successfully-stented cases. Post procedural strokes occurred in 4 patients (17.4%). One non-neurological death was identified in a patient who suffered a major post procedural stroke (4.3%). Conclusion: Intracranial atherosclerotic disease is not uncommon in our population. Angioplasty and stenting might be a valid option for the treatment of patients with recurrent symptoms despite optimal medical treatment. PMID:27744470

  13. A Proteomic Focus on the Alterations Occurring at the Human Atherosclerotic Coronary Intima*

    PubMed Central

    de la Cuesta, Fernando; Alvarez-Llamas, Gloria; Maroto, Aroa S.; Donado, Alicia; Zubiri, Irene; Posada, Maria; Padial, Luis R.; Pinto, Angel G.; Barderas, Maria G.; Vivanco, Fernando

    2011-01-01

    Coronary atherosclerosis still represents the major cause of mortality in western societies. Initiation of atherosclerosis occurs within the intima, where major histological and molecular changes are produced during pathogenesis. So far, proteomic analysis of the atherome plaque has been mainly tackled by the analysis of the entire tissue, which may be a challenging approach because of the great complexity of this sample in terms of layers and cell type composition. Based on this, we aimed to study the intimal proteome from the human atherosclerotic coronary artery. For this purpose, we analyzed the intimal layer from human atherosclerotic coronaries, which were isolated by laser microdissection, and compared with those from preatherosclerotic coronary and radial arteries, using a two-dimensional Differential-In-Gel-Electrophoresis (DIGE) approach. Results have pointed out 13 proteins to be altered (seven up-regulated and six down-regulated), which are implicated in the migrative capacity of vascular smooth muscle cells, extracellular matrix composition, coagulation, apoptosis, heat shock response, and intraplaque hemorrhage deposition. Among these, three proteins (annexin 4, myosin regulatory light 2, smooth muscle isoform, and ferritin light chain) constitute novel atherosclerotic coronary intima proteins, because they were not previously identified at this human coronary layer. For this reason, these novel proteins were validated by immunohistochemistry, together with hemoglobin and vimentin, in an independent cohort of arteries. PMID:21248247

  14. Science to Practice: Does FDG Differentiate Morphologically Unstable from Stable Atherosclerotic Plaque?

    PubMed

    Dilsizian, Vasken; Jadvar, Hossein

    2017-04-01

    It has been reported that fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) may detect the inflammatory state and macrophage burden of atherosclerotic plaques and potentially identify vulnerable plaques. However, published reports have been inconsistent in this area. Tavakoli et al ( 1 ) hypothesized that differential regulation of macrophage glucose metabolism by macrophage colony-stimulating factor (M-CSF; inflammation resolving) and granulocyte-M-CSF (GM-CSF; proinflammatory) may contribute to the inconsistency of FDG vessel wall inflammation. After the induction of inflammatory and metabolic profiles, both M-CSF and GM-CSF generated comparable levels of glucose uptake in cultured macrophages and murine atherosclerotic plaques. These findings suggest that although FDG uptake is an indicator of vascular macrophage burden (total number of macrophages), it may not necessarily differentiate morphologically unstable (inflammatory) from stable (noninflammatory) atherosclerotic plaque. Moreover, although atherosclerosis is characterized by macrophage-predominated inflammation, there is a wide range of other vascular diseases in which macrophages and inflammation play an important role in the absence of atherosclerosis. FDG uptake will be indistinguishable in atherosclerosis from large-artery inflammatory vascular disease, such as Takayasu arteritis, chemotherapy- or radiation-induced vascular inflammation, or foreign-body reaction, such as synthetic arterial graft. Because of the nonspecific nature of FDG uptake by any cell (upregulated under hypoxic conditions or other microenvironmental factors), this work calls for a more cautious approach to interpreting vascular FDG uptake as indicative of inflammatory atherosclerosis in the clinical setting.

  15. Relationship of MMP-14 and TIMP-3 Expression with Macrophage Activation and Human Atherosclerotic Plaque Vulnerability

    PubMed Central

    Johnson, Jason L.; Jenkins, Nicholas P.; Huang, Wei-Chun; Sala-Newby, Graciela B.; Scholtes, Vincent P. W.; Moll, Frans L.; Pasterkamp, Gerard; Newby, Andrew C.

    2014-01-01

    Matrix metalloproteinase-14 (MMP-14) promotes vulnerable plaque morphology in mice, whereas tissue inhibitor of metalloproteinases-3 (TIMP-3) overexpression is protective. MMP-14hi  TIMP-3lo rabbit foam cells are more invasive and more prone to apoptosis than MMP-14lo  TIMP-3hi cells. We investigated the implications of these findings for human atherosclerosis. In vitro generated macrophages and foam-cell macrophages, together with atherosclerotic plaques characterised as unstable or stable, were examined for expression of MMP-14, TIMP-3, and inflammatory markers. Proinflammatory stimuli increased MMP-14 and decreased TIMP-3 mRNA and protein expression in human macrophages. However, conversion to foam-cells with oxidized LDL increased MMP-14 and decreased TIMP-3 protein, independently of inflammatory mediators and partly through posttranscriptional mechanisms. Within atherosclerotic plaques, MMP-14 was prominent in foam-cells with either pro- or anti-inflammatory macrophage markers, whereas TIMP-3 was present in less foamy macrophages and colocalised with CD206. MMP-14 positive macrophages were more abundant whereas TIMP-3 positive macrophages were less abundant in plaques histologically designated as rupture prone. We conclude that foam-cells characterised by high MMP-14 and low TIMP-3 expression are prevalent in rupture-prone atherosclerotic plaques, independent of pro- or anti-inflammatory activation. Therefore reducing MMP-14 activity and increasing that of TIMP-3 could be valid therapeutic approaches to reduce plaque rupture and myocardial infarction. PMID:25301980

  16. Extensive demethylation of normally hypermethylated CpG islands occurs in human atherosclerotic arteries.

    PubMed

    Castillo-Díaz, Silvia A; Garay-Sevilla, María E; Hernández-González, Martha A; Solís-Martínez, Martha O; Zaina, Silvio

    2010-11-01

    Global DNA hypomethylation potentially leading to pro-atherogenic gene expression occurs in atherosclerotic lesions. However, limited information is available on the genomic location of hypomethylated sequences. We present a microarray-based survey of the methylation status of CpG islands (CGIs) in 45 human atherosclerotic arteries and 16 controls. Data from 10,367 CGIs revealed that a subset (151 or 1.4%) of these was hypermethylated in control arteries. The vast majority (142 or 94%) of this CGI subset was found to be unmethylated or partially methylated in atherosclerotic tissue, while only 17 of the normally unmethylated CGIs were hypermethylated in the diseased tissue. The most common functional classes among annotated genes adjacent to or containing differentially methylated CGIs, were transcription (23%) and signalling factors (16%). The former included HOX members, PROX1, NOTCH1 and FOXP1, which are known to regulate key steps of atherogenesis. Expression analysis revealed differential expression of all CGI-associated genes analysed. Sequence analysis identified novel DNA motifs with regulatory potential, associated with differentially methylated CGIs. This study is the first large-scale analysis of DNA methylation in atherosclerosis. Our data suggest that aberrant DNA methylation in atherosclerosis affects the transcription of critical regulatory genes for the induction of a pro-atherogenic cellular phenotype.

  17. Marked Acceleration of Atherosclerosis following Lactobacillus casei induced Coronary Arteritis in a Mouse Model of Kawasaki Disease

    PubMed Central

    Chen, Shuang; Lee, Young Ho; Crother, Timothy R.; Fishbein, Michael; Zhang, Wenxuan; Yilmaz, Atilla; Shimada, Kenichi; Schulte, Danica J; Lehman, Thomas J.A.; Shah, Prediman K.; Arditi, Moshe

    2012-01-01

    Objective To investigate if Lactobacillus casei cell wall extract (LCWE)-induced Kawasaki Disease (KD) accelerates atherosclerosis in hypercholesterolemic mice. Method and Resuslts Apoe−/− or Ldlr−/− mice were injected with LCWE (KD mice) or PBS, fed high fat diet for 8 weeks, and atherosclerotic lesions in aortic sinuses (AS), arch (AC) and whole aorta were assessed. KD mice had larger, more complex aortic lesions with abundant collagen, and both extracellular and intracellular lipid and foam cells, compared to lesions in control mice despite similar cholesterol levels. Both Apoe−/− KD and Ldlr−/− KD mice showed dramatic acceleration in atherosclerosis vs. controls, with increases in en face aortic atherosclerosis and plaque size in both the AS and AC plaques. Accelerated atherosclerosis was associated with increased circulating IL-12p40, IFN-γ, TNF-α, and increased macrophage, DC, and T cell recruitment in lesions. Furthermore, daily injections of the IL-1Ra, which inhibits LCWE induced KD vasculitis, prevented the acceleration of atherosclerosis. Conclusions Our results suggest an important pathophysiologic link between coronary arteritis/vasculitis in the KD mouse model and subsequent atherosclerotic acceleration, supporting the concept that a similar relation may also be present in KD patients. These results also suggest that KD in childhood may predispose to accelerated and early atherosclerosis as adults. PMID:22628430

  18. Osteopontin is elevated during neointima formation in rat arteries and is a novel component of human atherosclerotic plaques.

    PubMed Central

    Giachelli, C M; Bae, N; Almeida, M; Denhardt, D T; Alpers, C E; Schwartz, S M

    1993-01-01

    In an earlier report, we used differential cloning to identify genes that might be critical in controlling arterial neointima formation (Giachelli, C., N. Bae, D. Lombardi, M. Majesky, and S. Schwartz. 1991. Biochem. Biophys. Res. Commun. 177:867-873). In this study, we sequenced the complete cDNA and conclusively identified one of these genes, 2B7, as rat osteopontin. Using immunochemistry and in situ hybridization, we found that medial smooth muscle cells (SMC) in uninjured arteries contained very low levels of osteopontin protein and mRNA. Injury to either the adult rat aorta or carotid artery using a balloon catheter initiated a qualitatively similar time-dependent increase in both osteopontin protein and mRNA in arterial SMC. Expression was transient and highly localized to neointimal SMC during the proliferative and migratory phases of arterial injury, suggesting a possible role for osteopontin in these processes. In vitro, basic fibroblast growth factor (bFGF), transforming growth factor-beta (TGF-beta), and angiotensin II (AII), all proteins implicated in the rat arterial injury response, elevated osteopontin expression in confluent vascular SMC. Finally, we found that osteopontin was a novel component of the human atherosclerotic plaque found most strikingly associated with calcified deposits. These data implicate osteopontin as a potentially important mediator of arterial neointima formation as well as dystrophic calcification that often accompanies this process. Images PMID:8408622

  19. Future accelerator technology

    SciTech Connect

    Sessler, A.M.

    1986-05-01

    A general discussion is presented of the acceleration of particles. Upon this foundation is built a categorization scheme into which all accelerators can be placed. Special attention is devoted to accelerators which employ a wake-field mechanism and a restricting theorem is examined. It is shown how the theorem may be circumvented. Comments are made on various acceleration schemes.

  20. ACCELERATION AND THE GIFTED.

    ERIC Educational Resources Information Center

    GIBSON, ARTHUR R.; STEPHANS, THOMAS M.

    ACCELERATION OF PUPILS AND SUBJECTS IS CONSIDERED A MEANS OF EDUCATING THE ACADEMICALLY GIFTED STUDENT. FIVE INTRODUCTORY ARTICLES PROVIDE A FRAMEWORK FOR THINKING ABOUT ACCELERATION. FIVE PROJECT REPORTS OF ACCELERATED PROGRAMS IN OHIO ARE INCLUDED. ACCELERATION IS NOW BEING REGARDED MORE FAVORABLY THAN FORMERLY, BECAUSE METHODS HAVE BEEN…

  1. Laser driven ion accelerator

    DOEpatents

    Tajima, Toshiki

    2005-06-14

    A system and method of accelerating ions in an accelerator to optimize the energy produced by a light source. Several parameters may be controlled in constructing a target used in the accelerator system to adjust performance of the accelerator system. These parameters include the material, thickness, geometry and surface of the target.

  2. Laser driven ion accelerator

    DOEpatents

    Tajima, Toshiki

    2006-04-18

    A system and method of accelerating ions in an accelerator to optimize the energy produced by a light source. Several parameters may be controlled in constructing a target used in the accelerator system to adjust performance of the accelerator system. These parameters include the material, thickness, geometry and surface of the target.

  3. Calculation of arterial wall temperature in atherosclerotic arteries: effect of pulsatile flow, arterial geometry, and plaque structure

    PubMed Central

    Ley, Obdulia; Kim, Taehong

    2007-01-01

    Background This paper presents calculations of the temperature distribution in an atherosclerotic plaque experiencing an inflammatory process; it analyzes the presence of hot spots in the plaque region and their relationship to blood flow, arterial geometry, and inflammatory cell distribution. Determination of the plaque temperature has become an important topic because plaques showing a temperature inhomogeneity have a higher likelihood of rupture. As a result, monitoring plaque temperature and knowing the factors affecting it can help in the prevention of sudden rupture. Methods The transient temperature profile in inflamed atherosclerotic plaques is calculated by solving an energy equation and the Navier-Stokes equations in 2D idealized arterial models of a bending artery and an arterial bifurcation. For obtaining the numerical solution, the commercial package COMSOL 3.2 was used. The calculations correspond to a parametric study where arterial type and size, as well as plaque geometry and composition, are varied. These calculations are used to analyze the contribution of different factors affecting arterial wall temperature measurements. The main factors considered are the metabolic heat production of inflammatory cells, atherosclerotic plaque length lp, inflammatory cell layer length lmp, and inflammatory cell layer thickness dmp. Results The calculations indicate that the best location to perform the temperature measurement is at the back region of the plaque (0.5 ≤ l/lp ≤ 0.7). The location of the maximum temperature, or hot spot, at the plaque surface can move during the cardiac cycle depending on the arterial geometry and is a direct result of the blood flow pattern. For the bending artery, the hot spot moves 0.6 millimeters along the longitudinal direction; for the arterial bifurcation, the hot spot is concentrated at a single location due to the flow recirculation observed at both ends of the plaque. Focusing on the thermal history of different

  4. EDITORIAL: Laser and plasma accelerators Laser and plasma accelerators

    NASA Astrophysics Data System (ADS)

    Bingham, Robert

    2009-02-01

    This special issue on laser and plasma accelerators illustrates the rapid advancement and diverse applications of laser and plasma accelerators. Plasma is an attractive medium for particle acceleration because of the high electric field it can sustain, with studies of acceleration processes remaining one of the most important areas of research in both laboratory and astrophysical plasmas. The rapid advance in laser and accelerator technology has led to the development of terawatt and petawatt laser systems with ultra-high intensities and short sub-picosecond pulses, which are used to generate wakefields in plasma. Recent successes include the demonstration by several groups in 2004 of quasi-monoenergetic electron beams by wakefields in the bubble regime with the GeV energy barrier being reached in 2006, and the energy doubling of the SLAC high-energy electron beam from 42 to 85 GeV. The electron beams generated by the laser plasma driven wakefields have good spatial quality with energies ranging from MeV to GeV. A unique feature is that they are ultra-short bunches with simulations showing that they can be as short as a few femtoseconds with low-energy spread, making these beams ideal for a variety of applications ranging from novel high-brightness radiation sources for medicine, material science and ultrafast time-resolved radiobiology or chemistry. Laser driven ion acceleration experiments have also made significant advances over the last few years with applications in laser fusion, nuclear physics and medicine. Attention is focused on the possibility of producing quasi-mono-energetic ions with energies ranging from hundreds of MeV to GeV per nucleon. New acceleration mechanisms are being studied, including ion acceleration from ultra-thin foils and direct laser acceleration. The application of wakefields or beat waves in other areas of science such as astrophysics and particle physics is beginning to take off, such as the study of cosmic accelerators considered

  5. Atherosclerotic inferior mesenteric artery stenosis resulting in large intestinal hypoperfusion: a paradigm shift in the diagnosis and management of symptomatic chronic mesenteric ischemia.

    PubMed

    Lotun, Kapildeo; Shetty, Ranjith; Topaz, On

    2012-11-01

    Symptomatic chronic mesenteric ischemia results from intestinal hypoperfusion and is classically thought to result from involvement of two or more mesenteric arteries. The celiac artery and superior mesenteric artery are most frequently implicated in this disease process, and their involvement usually results in symptoms of small intestinal ischemia. Symptomatic chronic mesenteric ischemia resulting predominantly from inferior mesenteric artery involvement has largely been overlooked but does gives rise to its own, unique clinical presentation with symptoms resulting from large intestinal ischemia. We present four patients with atherosclerotic inferior mesenteric artery stenosis with symptomatic chronic mesenteric ischemia that have unique clinical presentations consistent with large intestinal ischemia that resolved following percutaneous endovascular treatment of the inferior mesenteric artery stenosis. These cases represent a novel approach to the diagnosis and management of this disease process and may warrant a further subclassification of chronic mesenteric ischemia into chronic small intestinal ischemia and chronic large intestinal ischemia.

  6. Vulnerable atherosclerotic plaque elasticity reconstruction based on a segmentation-driven optimization procedure using strain measurements: theoretical framework.

    PubMed

    Le Floc'h, Simon; Ohayon, Jacques; Tracqui, Philippe; Finet, Gérard; Gharib, Ahmed M; Maurice, Roch L; Cloutier, Guy; Pettigrew, Roderic I

    2009-07-01

    It is now recognized that prediction of the vulnerable coronary plaque rupture requires not only an accurate quantification of fibrous cap thickness and necrotic core morphology but also a precise knowledge of the mechanical properties of plaque components. Indeed, such knowledge would allow a precise evaluation of the peak cap-stress amplitude, which is known to be a good biomechanical predictor of plaque rupture. Several studies have been performed to reconstruct a Young's modulus map from strain elastograms. It seems that the main issue for improving such methods does not rely on the optimization algorithm itself, but rather on preconditioning requiring the best estimation of the plaque components' contours. The present theoretical study was therefore designed to develop: 1) a preconditioning model to extract the plaque morphology in order to initiate the optimization process, and 2) an approach combining a dynamic segmentation method with an optimization procedure to highlight the modulogram of the atherosclerotic plaque. This methodology, based on the continuum mechanics theory prescribing the strain field, was successfully applied to seven intravascular ultrasound coronary lesion morphologies. The reconstructed cap thickness, necrotic core area, calcium area, and the Young's moduli of the calcium, necrotic core, and fibrosis were obtained with mean relative errors of 12%, 4% and 1%, 43%, 32%, and 2%, respectively.

  7. Focal toxicity of oxysterols in vascular smooth muscle cell culture. A model of the atherosclerotic core region.

    PubMed Central

    Guyton, J. R.; Black, B. L.; Seidel, C. L.

    1990-01-01

    Cell necrosis and reactive cellular processes in and near the atherosclerotic core region might result from short-range interactions with toxic lipids. To model these interactions in cell culture, focal crystalline deposits of cholestane-3 beta,5 alpha,6 beta-triol, 25-OH cholesterol, and cholesterol were overlaid by a collagen gel, on which canine aortic smooth muscle cells were seeded. Oxysterols, but not cholesterol, caused focally decreased plating efficiency and cell death, leading to the formation of a persistent circular gap in the cell culture. Cholestanetriol was largely removed from the culture dishes over 3 to 4 weeks, whereas cholesterol and 25-OH cholesterol were largely retained. Smooth muscle cells were motile even in proximity to oxysterol crystals, with occasional suicidal migration toward the crystals. Chemoattraction, however, could not be demonstrated. Despite toxicity, cholestanetriol did not appear to alter the fraction of cells exhibiting 3H-thymidine uptake, even in areas close to the crystals. Thus, oxysterols may be toxic to some cells, without causing major impairment of the migration and proliferation of nearby cells. This would allow the simultaneous occurrence of cell death and proliferation evident in atherosclerosis. Images Figure 2 Figure 4 Figure 5 PMID:2201200

  8. Vulnerable Atherosclerotic Plaque Elasticity Reconstruction Based on a Segmentation-Driven Optimization Procedure Using Strain Measurements: Theoretical Framework

    PubMed Central

    Le Floc’h, Simon; Tracqui, Philippe; Finet, Gérard; Gharib, Ahmed M.; Maurice, Roch L.; Cloutier, Guy; Pettigrew, Roderic I.

    2016-01-01

    It is now recognized that prediction of the vulnerable coronary plaque rupture requires not only an accurate quantification of fibrous cap thickness and necrotic core morphology but also a precise knowledge of the mechanical properties of plaque components. Indeed, such knowledge would allow a precise evaluation of the peak cap-stress amplitude, which is known to be a good biomechanical predictor of plaque rupture. Several studies have been performed to reconstruct a Young’s modulus map from strain elastograms. It seems that the main issue for improving such methods does not rely on the optimization algorithm itself, but rather on preconditioning requiring the best estimation of the plaque components’ contours. The present theoretical study was therefore designed to develop: 1) a preconditioning model to extract the plaque morphology in order to initiate the optimization process, and 2) an approach combining a dynamic segmentation method with an optimization procedure to highlight the modulogram of the atherosclerotic plaque. This methodology, based on the continuum mechanics theory prescribing the strain field, was successfully applied to seven intravascular ultrasound coronary lesion morphologies. The reconstructed cap thickness, necrotic core area, calcium area, and the Young’s moduli of the calcium, necrotic core, and fibrosis were obtained with mean relative errors of 12%, 4% and 1%, 43%, 32%, and 2%, respectively. PMID:19164080

  9. Impaired gait pattern as a sensitive tool to assess hypoxic brain damage in a novel mouse model of atherosclerotic plaque rupture.

    PubMed

    Roth, Lynn; Van Dam, Debby; Van der Donckt, Carole; Schrijvers, Dorien M; Lemmens, Katrien; Van Brussel, Ilse; De Deyn, Peter P; Martinet, Wim; De Meyer, Guido R Y

    2015-02-01

    Apolipoprotein E deficient (ApoE(-/-)) mice with a heterozygous mutation in the fibrillin-1 gene (Fbn1(C1039G+/-)) show spontaneous atherosclerotic plaque ruptures, disturbances in cerebral flow and sudden death when fed a Western-type diet (WD). The present study focused on motor coordination and spatial learning of ApoE(-/-) Fbn1(C1039G+/-) mice on WD for 20 weeks (n=21). ApoE(-/-) mice on WD (n=24) and ApoE(-/-) Fbn1(C1039G+/-) mice on normal diet (ND, n=21) served as controls. Starting from 10 weeks of diet, coordination was assessed every two weeks by the following tests: gait analysis, stationary beam, wire suspension and accelerating rotarod. The Morris water maze test was performed after 13 weeks of diet to study spatial learning. At the end of the experiment (20 weeks of WD), the mice were sacrificed and the brachiocephalic artery and brain were isolated. From 12 weeks onward, gait analysis of ApoE(-/-) Fbn1(C1039G+/-) mice on WD revealed a progressive increase in track width as compared to ApoE(-/-) mice on WD and ApoE(-/-) Fbn1(C1039G+/-) mice on ND (at 20 weeks: 29.8±0.6 mm vs. 25.8±0.4 mm and 26.0±0.5 mm). Moreover, the stationary beam test showed a decrease in motor coordination of ApoE(-/-) Fbn1(C1039G+/-) mice on WD at 18 and 20 weeks. The wire suspension test and accelerating rotarod could not detect signs of motor impairment. Spatial learning was also not affected. Histological analysis of the brachiocephalic artery showed larger and more stenotic plaques in ApoE(-/-) Fbn1(C1039G+/-) mice on WD. Furthermore, the parietal cortex of ApoE(-/-) Fbn1(C1039G+/-) mice on WD showed pyknotic nuclei as a sign of hypoxia and the percentage of pyknosis correlated with track width. In conclusion, gait analysis may be an efficient method for analyzing hypoxic brain damage in the ApoE(-/-) Fbn1(C1039G+/-) mouse model. This test could be of value to assess the effect of potential anti-atherosclerotic therapies in mice.

  10. Risk factors for accelerated atherosclerosis in young women with hyperprolactinemia.

    PubMed

    Medic-Stojanoska, Milica; Icin, Tijana; Pletikosic, Ivana; Bajkin, Ivana; Novakovic-Paro, Jovanka; Stokic, Edita; Spasic, Dragan T; Kovacev-Zavisic, Branka; Abenavoli, Ludovico

    2015-04-01

    Prolactin is a metabolic hormone. The hypothesis is that hyperprolactinemia can cause metabolic and inflammatory changes which are associated with accelerated atherosclerotic process, but the treatment of hyperprolactinemia with dopamine agonists, leads to reversibility of these processes. The first aim of this study was to determine whether hyperprolactinemia in premenopausal women is accompanied with the increase in body mass index (BMI), changes in body composition, lipid disturbances, the presence of inflammation and changes in systolic and diastolic blood pressure as risk factors for the development of early atherosclerosis. The second aim was to know whether the therapy of hyperprolactinemia and prolactin normalization lead to improvement of the observed parameters. Twenty female patients with prolactinomas, before and during treatment with dopamine agonists and 16 healthy controls were evaluated. Prolactin, BMI, total body fat, free fat mass, total body water, total cholesterol, triglycerides, high density lipoprotein (HDL), low density lipoprotein (LDL) and fibrinogen as well as systolic and diastolic blood pressure were measured at baseline and during the therapy. Hyperprolactinemic patients had pathologic and significantly higher levels of prolactin (PRL) than the controls (p=0.000). The BMI, body fat, total body water (TBW), total cholesterol, triglycerides, LDL were in normal range and higher in the patients than in the controls. HDL was lower in hyperprolactinemic females than controls. The difference was significant only for body fat (fat % p=0.006; fat kg p=0.009). Fibrinogen was slightly increased in patients compared with the controls. Hyperprolactinemic patients had normal, but increased levels of systolic and diastolic blood pressure compared with the controls. The difference with border significance was found in diastolic blood pressure (p=0.065). The correlation of PRL with all the observed parameters was positive apart from HDL, but relatively

  11. Development of PUNDA (Parametric Universal Nonlinear Dynamics Approximator) Models for Self-Validating Knowledge-Guided Modelling of Nonlinear Processes in Particle Accelerators \\& Industry

    SciTech Connect

    Sayyar-Rodsari, Bijan; Schweiger, Carl; Hartman, Eric

    2007-10-07

    The difficult problems being tackled in the accelerator community are those that are nonlinear, substantially unmodeled, and vary over time. Such problems are ideal candidates for model-based optimization and control if representative models of the problem can be developed that capture the necessary mathematical relations and remain valid throughout the operation region of the system, and through variations in system dynamics. The goal of this proposal is to develop the methodology and the algorithms for building high-fidelity mathematical representations of complex nonlinear systems via constrained training of combined first-principles and neural network models.

  12. A novel biomarker of coronary atherosclerosis: serum DKK1 concentration correlates with coronary artery calcification and atherosclerotic plaques.

    PubMed

    Kim, Kwang-Il; Park, Kyoung Un; Chun, Eun Ju; Choi, Sang Il; Cho, Young-Seok; Youn, Tae-Jin; Cho, Goo-Yeong; Chae, In-Ho; Song, Junghan; Choi, Dong-Ju; Kim, Cheol-Ho

    2011-09-01

    DKK1 modulates Wnt signaling, which is involved in the atherosclerosis. However, no data exist regarding the usefulness of measuring serum DKK1 concentration in predicting coronary atherosclerosis. A total of 270 consecutive patients (62.8 ± 11.2 yr; 70% male) were included. A contrast-enhanced 64-slice coronary MDCT was performed to identify the presence of atherosclerotic plaques. Agatston calcium scores (CS) were calculated to quantify the coronary artery calcification (CAC). DKK1 concentrations were measured by enzyme-linked immunosorbent assay. For each subsequent DKK1 quartile, there was a significant increase in CAC (P = 0.004) and the number of segments with coronary atherosclerosis (P < 0.001). In addition, DKK1 concentration was significantly higher in patients with atherosclerotic plaques, regardless of plaque composition (P = 0.01). Multivariate analysis identified DKK1 as an independent risk factor for the presence of coronary atherosclerotic plaque. The adjusted odds ratio for coronary atherosclerotic plaque was 4.88 (95% CI, 1.67 to 14.25) for highest versus lowest quartile of the DKK1 levels. Furthermore, patients with DKK1 concentrations ≥ 68.6 pg/mL demonstrated coronary atherosclerotic plaques even when they had low CS. Serum DKK1 concentrations correlate with the coronary atherosclerosis and play an independent role in predicting the presence of coronary atherosclerosis.

  13. Cohort study of predictive value of urinary albumin excretion for atherosclerotic vascular disease in patients with insulin dependent diabetes.

    PubMed Central

    Deckert, T.; Yokoyama, H.; Mathiesen, E.; Rønn, B.; Jensen, T.; Feldt-Rasmussen, B.; Borch-Johnsen, K.; Jensen, J. S.

    1996-01-01

    OBJECTIVE: To examine whether slightly elevated urinary albumin excretion precedes development of atherosclerotic vascular disease in patients with insulin dependent diabetes independently of conventional atherogenic risk factors and of diabetic nephropathy. DESIGN: Cohort study with 11 year follow up. SETTING: Diabetes centre in Denmark. SUBJECTS: 259 patients aged 19-51 with insulin dependent diabetes of 6-34 years' duration and without atherosclerotic vascular disease or diabetic nephropathy at baseline. MAIN OUTCOME MEASURES: Baseline variables: urinary albumin excretion, blood pressure, smoking habits, and serum concentrations of total cholesterol, high density lipoprotein cholesterol, sialic acid, and von Willebrand factor. End point: atherosclerotic vascular disease assessed by death certificates, mailed questionnaires, and hospital records. RESULTS: Thirty patients developed atherosclerotic vascular disease during follow up of 2457 person year. Elevated urinary albumin excretion was significantly predictive of atherosclerotic vascular disease (hazard ratio 1.06 (95% confidence interval 1.02 to 1.18) per 5 mg increase in 24 hour urinary albumin excretion, P = 0.002). Predictive effect was independent of age; sex; blood pressure; smoking; serum concentrations of total cholesterol, high density lipoprotein cholesterol, sialic acid, and von Willebrand factor; level of haemoglobin A(lc); insulin dose, duration of diabetes, and diabetic nephropathy (hazard ratio 1.04 (1.01 to 1.08) per 5 mg increase PMID:8611873

  14. Community Petascale Project for Accelerator Science and Simulation: Advancing Computational Science for Future Accelerators and Accelerator Technologies

    SciTech Connect

    Spentzouris, P.; Cary, J.; McInnes, L.C.; Mori, W.; Ng, C.; Ng, E.; Ryne, R.; /LBL, Berkeley

    2011-11-14

    The design and performance optimization of particle accelerators are essential for the success of the DOE scientific program in the next decade. Particle accelerators are very complex systems whose accurate description involves a large number of degrees of freedom and requires the inclusion of many physics processes. Building on the success of the SciDAC-1 Accelerator Science and Technology project, the SciDAC-2 Community Petascale Project for Accelerator Science and Simulation (ComPASS) is developing a comprehensive set of interoperable components for beam dynamics, electromagnetics, electron cooling, and laser/plasma acceleration modelling. ComPASS is providing accelerator scientists the tools required to enable the necessary accelerator simulation paradigm shift from high-fidelity single physics process modeling (covered under SciDAC1) to high-fidelity multiphysics modeling. Our computational frameworks have been used to model the behavior of a large number of accelerators and accelerator R&D experiments, assisting both their design and performance optimization. As parallel computational applications, the ComPASS codes have been shown to make effective use of thousands of processors. ComPASS is in the first year of executing its plan to develop the next-generation HPC accelerator modeling tools. ComPASS aims to develop an integrated simulation environment that will utilize existing and new accelerator physics modules with petascale capabilities, by employing modern computing and solver technologies. The ComPASS vision is to deliver to accelerator scientists a virtual accelerator and virtual prototyping modeling environment, with the necessary multiphysics, multiscale capabilities. The plan for this development includes delivering accelerator modeling applications appropriate for each stage of the ComPASS software evolution. Such applications are already being used to address challenging problems in accelerator design and optimization. The ComPASS organization

  15. Treatment of patients with aortic atherosclerotic disease with paclitaxel-associated lipid nanoparticles

    PubMed Central

    Shiozaki, Afonso A.; Senra, Tiago; Morikawa, Aleksandra T.; Deus, Débora F.; Paladino, Antonio T; Pinto, Ibraim M.F.; Maranhão, Raul C.

    2016-01-01

    OBJECTIVE: The toxicity of anti-cancer chemotherapeutic agents can be reduced by associating these compounds, such as the anti-proliferative agent paclitaxel, with a cholesterol-rich nanoemulsion (LDE) that mimics the lipid composition of low-density lipoprotein (LDL). When injected into circulation, the LDE concentrates the carried drugs in neoplastic tissues and atherosclerotic lesions. In rabbits, atherosclerotic lesion size was reduced by 65% following LDE-paclitaxel treatment. The current study aimed to test the effectiveness of LDE-paclitaxel on inpatients with aortic atherosclerosis. METHODS: This study tested a 175 mg/m2 body surface area dose of LDE-paclitaxel (intravenous administration, 3/3 weeks for 6 cycles) in patients with aortic atherosclerosis who were aged between 69 and 86 yrs. A control group of 9 untreated patients with aortic atherosclerosis (72-83 yrs) was also observed. RESULTS: The LDE-paclitaxel treatment elicited no important clinical or laboratory toxicities. Images were acquired via multiple detector computer tomography angiography (64-slice scanner) before treatment and at 1-2 months after treatment. The images showed that the mean plaque volume in the aortic artery wall was reduced in 4 of the 8 patients, while in 3 patients it remained unchanged and in one patient it increased. In the control group, images were acquired twice with an interval of 6-8 months. None of the patients in this group exhibited a reduction in plaque volume; in contrast, the plaque volume increased in three patients and remained stable in four patients. During the study period, one death unrelated to the treatment occurred in the LDE-paclitaxel group and one death occurred in the control group. CONCLUSION: Treatment with LDE-paclitaxel was tolerated by patients with cardiovascular disease and showed the potential to reduce atherosclerotic lesion size. PMID:27626473

  16. MicroRNA-containing microvesicles regulating inflammation in association with atherosclerotic disease.

    PubMed

    Hulsmans, Maarten; Holvoet, Paul

    2013-10-01

    In addition to intracellular organelles, eukaryotic cells contain extracellular organelles which are released, or shed, into the microenvironment. In practice, most human studies have examined mixed populations containing both exosomes and shedding microvesicles (also called ectosomes or microparticles); only a few studies have rigorously distinguished between the two. Accordingly, in this review, exosomes and shedding microvesicles are collectively called microvesicles. The first aim of this review was to discuss the role of microvesicles in cell-to-cell communication in general and in specific interactions between cells in chronic inflammation associated with atherosclerotic disease. Hereby, we focused on cell-specific microvesicles derived from platelets, endothelial cells and monocyte and monocyte-derived cells. The latter were also found to be associated with inflammation in obesity and type 2 diabetes prior to atherosclerotic disease, and cancer. Our second aim was to discuss specific changes in microvesicle content in relation with inflammation associated with metabolic and atherosclerotic disease, and cancer. Because many studies supported the putative diagnostic value of microRNAs, we emphasized therein changes in microRNA content rather than protein or lipid content. The most interesting microRNAs in inflammatory microvesicles in association with metabolic and cardiovascular diseases were found to be the let-7 family, miR-17/92 family, miR-21, miR-29, miR-126, miR-133, miR-146, and miR-155. These data warrant further investigation of the potential of microvesicles as putative biomarkers and as novel carriers for the cell-specific transfer of microRNAs and other therapeutic agents.

  17. Anti-atherosclerotic potential of gossypetin via inhibiting LDL oxidation and foam cell formation

    SciTech Connect

    Chen, Jing-Hsien; Tsai, Chia-Wen; Wang, Chi-Ping; Lin, Hui-Hsuan

    2013-10-15

    Gossypetin, a flavone originally isolated from Hibiscus species, has been shown to possess antioxidant, antimicrobial, and antimutagenic activities. Here, we investigated the mechanism(s) underlying the anti-atherosclerotic potential of gossypetin. 1,1-Diphenyl-2-picrylhydrazyl (DPPH) scavenging activity assay showed that the addition of > 50 μM of gossypetin could scavenge over 50% of DPPH radicals. The inhibitory effects of gossypetin on the lipid and protein oxidation of LDL were defined by thiobarbituric acid reactive substance (TBARS) assay, the relative electrophoretic mobility (REM) of oxidized LDL (ox-LDL), and fragmentation of apoB in the Cu{sup 2+}-induced oxidation of LDL. Gossypetin showed potential in reducing ox-LDL-induced foam cell formation and intracellular lipid accumulation, and uptake ability of macrophages under non-cytotoxic concentrations. Molecular data showed that these influences of gossypetin might be mediated via peroxisome proliferator-activated receptor α (PPARα)/liver-X receptor α (LXRα)/ATP-binding cassette transporter A1 (ABCA1) and PPARγ/scavenger receptor CD36 pathways, as demonstrated by the transfection of PPARα siRNA or PPARγ expression vector. Our data implied that gossypetin regulated the PPAR signals, which in turn led to stimulation of cholesterol removal from macrophages and delay atherosclerosis. These results suggested that gossypetin potentially could be developed as an anti-atherosclerotic agent. - Highlights: • The anti-atherosclerotic effect of gossypetin in vitro was examined. • Gossypetin inhibited LDL oxidation. • Gossypetin showed potential in reducing on the formation of foam cells. • Gossypetin functions against ox-LDL through PPARa activation and PPARγ depression.

  18. Arsenic exacerbates atherosclerotic lesion formation and inflammation in ApoE-/- mice

    SciTech Connect

    Srivastava, Sanjay; Vladykovskaya, Elena N.; Haberzettl, Petra; Sithu, Srinivas D.; D'Souza, Stanley E.; States, J. Christopher

    2009-11-15

    Exposure to arsenic-contaminated water has been shown to be associated with cardiovascular disease, especially atherosclerosis. We examined the effect of arsenic exposure on atherosclerotic lesion formation, lesion composition and nature in ApoE-/- mice. Early post-natal exposure (3-week-old mice exposed to 49 ppm arsenic as NaAsO{sub 2} in drinking water for 7 weeks) increased the atherosclerotic lesion formation by 3- to 5-fold in the aortic valve and the aortic arch, without affecting plasma cholesterol. Exposure to arsenic for 13 weeks (3-week-old mice exposed to 1, 4.9 and 49 ppm arsenic as NaAsO{sub 2} in drinking water) increased the lesion formation and macrophage accumulation in a dose-dependent manner. Temporal studies showed that continuous arsenic exposure significantly exacerbated the lesion formation throughout the aortic tree at 16 and 36 weeks of age. Withdrawal of arsenic for 12 weeks after an initial exposure for 21 weeks (to 3-week-old mice) significantly decreased lesion formation as compared with mice continuously exposed to arsenic. Similarly, adult exposure to 49 ppm arsenic for 24 weeks, starting at 12 weeks of age increased lesion formation by 2- to 3.6-fold in the aortic valve, the aortic arch and the abdominal aorta. Lesions of arsenic-exposed mice displayed a 1.8-fold increase in macrophage accumulation whereas smooth muscle cell and T-lymphocyte contents were not changed. Expression of pro-inflammatory chemokine MCP-1 and cytokine IL-6 and markers of oxidative stress, protein-HNE and protein-MDA adducts were markedly increased in lesions of arsenic-exposed mice. Plasma concentrations of MCP-1, IL-6 and MDA were also significantly elevated in arsenic-exposed mice. These data suggest that arsenic exposure increases oxidative stress, inflammation and atherosclerotic lesion formation.

  19. Chronic intermittent mental stress promotes atherosclerotic plaque vulnerability, myocardial infarction and sudden death in mice.

    PubMed

    Roth, Lynn; Rombouts, Miche; Schrijvers, Dorien M; Lemmens, Katrien; De Keulenaer, Gilles W; Martinet, Wim; De Meyer, Guido R Y

    2015-09-01

    Vulnerable atherosclerotic plaques are prone to plaque rupture leading to acute cardiovascular syndromes and death. Elucidating the risk of plaque rupture is important to define better therapeutic or preventive strategies. In the present study, we investigated the effect of chronic intermittent mental stress on atherosclerotic plaque stability and cardiovascular mortality in apolipoprotein E-deficient (ApoE(-/-)) mice with a heterozygous mutation in the fibrillin-1 gene (Fbn1(C1039G+/)(-)). This mouse model displays exacerbated atherosclerosis with spontaneous plaque ruptures, myocardial infarction and sudden death, when fed a Western-type diet (WD). Female ApoE(-/-)Fbn1(C1039G+/-) mice were fed a WD for up to 25 weeks. After 10 weeks WD, mice were divided in a control (n = 27) and mental stress (n = 29) group. The chronic intermittent mental stress protocol consisted of 3 triggers: water avoidance, damp bedding and restraint stress, in a randomly assigned order lasting 6 h every weekday for 15 weeks. Chronic intermittent mental stress resulted in a significant increase in the amount of macrophages in atherosclerotic plaques of the proximal ascending aorta, whereas type I collagen and fibrous cap thickness were decreased. The coronary arteries of mental stress-treated mice showed larger plaques, more stenosis, and an increased degree of perivascular fibrosis. Moreover, myocardial infarctions occurred more frequently in the mental stress group. As compared to the control group, the survival of stressed ApoE(-/-)Fbn1(C1039G+/-) mice decreased from 67% to 52% at 25 weeks WD, presumably due to myocardial infarctions. In conclusion, chronic intermittent mental stress promotes plaque instability, myocardial infarctions, and mortality of ApoE(-/-)Fbn1(C1039G+/-) mice.

  20. Decreased early atherosclerotic lesions in hypertriglyceridemic mice expressing cholesteryl ester transfer protein transgene.

    PubMed Central

    Hayek, T; Masucci-Magoulas, L; Jiang, X; Walsh, A; Rubin, E; Breslow, J L; Tall, A R

    1995-01-01

    The human cholesteryl ester transfer protein (CETP) facilitates the transfer of cholesteryl ester from HDL to triglyceride-rich lipoproteins. The activity of CETP results in a reduction in HDL cholesterol levels, but CETP may also promote reverse cholesterol transport. Thus, the net impact of CETP expression on atherogenesis is uncertain. The influence of hypertriglyceridemia and CETP on the development of atherosclerotic lesions in the proximal aorta was assessed by feeding transgenic mice a high cholesterol diet for 16 wk. 13 out of 14 (93%) hypertriglyceridemic human apo CIII (HuCIII) transgenic (Tg) mice developed atherosclerotic lesions, compared to 18 out of 29 (62%) controls. In HuCIII/CETPTg, human apo AI/CIIITg and HuAI/CIII/CETPTg mice, 7 of 13 (54%), 5 of 10 (50%), and 5 of 13 (38%), respectively, developed lesions in the proximal aorta (P < .05 compared to HuCIIITg). The average number of aortic lesions per mouse in HuCIIITg and controls was 3.4 +/- 0.8 and 2.7 +/- 0.6, respectively in HuCIII/CETPTg, HuAI/CIIIg, and HuAI/CIII/CETPTg mice the number of lesions was significantly lower than in HuCIIITg and control mice: 0.9 +/- 0.4, 1.5 +/- 0.5, and 0.9 +/- 0.4, respectively. There were parallel reductions in mean lesion area. In a separate study, we found an increased susceptibility to dietary atherosclerosis in nonhypertriglyceridemic CETP transgenic mice compared to controls. We conclude that CETP expression inhibits the development of early atherosclerotic lesions but only in hypertriglyceridemic mice. PMID:7560101

  1. A computational fluid-structure interaction model for plaque vulnerability assessment in atherosclerotic human coronary arteries

    NASA Astrophysics Data System (ADS)

    Karimi, Alireza; Navidbakhsh, Mahdi; Razaghi, Reza; Haghpanahi, Mohammad

    2014-04-01

    Coronary artery disease is responsible for a third of global deaths worldwide. Computational simulations of blood flow can be used to understand the interactions of artery/plaque and blood in coronary artery disease and to better predict the rupture of atherosclerotic plaques. So far, the mechanical properties of animals' coronary artery have been mostly used for hemodynamic simulation of atherosclerotic arteries. The mechanical properties of animals' coronary arteries are often not accurate enough and can be only used for an approximate estimation and comparative assessment of the cognate parameters in human. In this study, a three-dimensional (3D) computational fluid-structure interactions model with three different plaque types is presented to perform a more accurate plaque vulnerability assessment for human atherosclerotic plaques. The coronary arteries of twenty-two male individuals were removed during autopsy and subjected to uniaxial tensile loading. The hyperelastic material coefficients of coronary arteries were calculated and implemented to the computational model. The fully coupled fluid and structure models were solved using the explicit dynamics finite element code LS-DYNA. The normal and shear stresses induced within the plaques were significantly affected by different plaque types. The highest von Mises (153 KPa) and shear (57 KPa) stresses were observed for hypocellular plaques, while the lowest von Mises (70 KPa) and shear (39 KPa) stresses were observed on the stiffer calcified plaques. The results suggest that the risk of plaque rupture due to blood flow is lower for cellular and hypocellular plaques, while higher for calcified plaques with low fracture stresses.

  2. Lectin Pathway of Complement Activation Is Associated with Vulnerability of Atherosclerotic Plaques

    PubMed Central

    Fumagalli, Stefano; Perego, Carlo; Zangari, Rosalia; De Blasio, Daiana; Oggioni, Marco; De Nigris, Francesca; Snider, Francesco; Garred, Peter; Ferrante, Angela M. R.; De Simoni, Maria-Grazia

    2017-01-01

    Inflammatory mechanisms may be involved in atherosclerotic plaque rupture. By using a novel histology-based method to quantify plaque instability here, we assess whether lectin pathway (LP) of complement activation, a major inflammation arm, could represent an index of plaque instability. Plaques from 42 consecutive patients undergoing carotid endarterectomy were stained with hematoxylin-eosin and the lipid core, cholesterol clefts, hemorrhagic content, thickness of tunica media, and intima, including or not infiltration of cellular debris and cholesterol, were determined. The presence of ficolin-1, -2, and -3 and mannose-binding lectin (MBL), LP initiators, was assessed in the plaques by immunofluorescence and in plasma by ELISA. LP activation was assessed in plasma by functional in vitro assays. Patients presenting low stenosis (≤75%) had higher hemorrhagic content than those with high stenosis (>75%), indicating increased erosion. Increased hemorrhagic content and tunica media thickness, as well as decreased lipid core and infiltrated content were associated with vulnerable plaques and therefore used to establish a plaque vulnerability score that allowed to classify patients according to plaque vulnerability. Ficolins and MBL were found both in plaques’ necrotic core and tunica media. Patients with vulnerable plaques showed decreased plasma levels and intraplaque deposition of ficolin-2. Symptomatic patients experiencing a transient ischemic attack had lower plasma levels of ficolin-1. We show that the LP initiators are present within the plaques and their circulating levels change in atherosclerotic patients. In particular, we show that decreased ficolin-2 levels are associated with rupture-prone vulnerable plaques, indicating its potential use as marker for cardiovascular risk assessment in atherosclerotic patients. PMID:28360913

  3. Accelerating Particles with Plasma

    ScienceCinema

    Litos, Michael; Hogan, Mark

    2016-07-12

    Researchers at SLAC explain how they use plasma wakefields to accelerate bunches of electrons to very high energies over only a short distance. Their experiments offer a possible path for the future of particle accelerators.

  4. Peak acceleration limiter

    NASA Technical Reports Server (NTRS)

    Chapman, C. P.

    1972-01-01

    Device is described that limits accelerations by shutting off shaker table power very rapidly in acceleration tests. Absolute value of accelerometer signal is used to trigger electronic switch which terminates test and sounds alarm.

  5. Linear Accelerator (LINAC)

    MedlinePlus

    ... equipment? How is safety ensured? What is this equipment used for? A linear accelerator (LINAC) is the ... Therapy (SBRT) . top of page How does the equipment work? The linear accelerator uses microwave technology (similar ...

  6. Accelerating Particles with Plasma

    SciTech Connect

    Litos, Michael; Hogan, Mark

    2014-11-05

    Researchers at SLAC explain how they use plasma wakefields to accelerate bunches of electrons to very high energies over only a short distance. Their experiments offer a possible path for the future of particle accelerators.

  7. Improved plasma accelerator

    NASA Technical Reports Server (NTRS)

    Cheng, D. Y.

    1971-01-01

    Converging, coaxial accelerator electrode configuration operates in vacuum as plasma gun. Plasma forms by periodic injections of high pressure gas that is ionized by electrical discharges. Deflagration mode of discharge provides acceleration, and converging contours of plasma gun provide focusing.

  8. Accelerator Technology Division

    NASA Astrophysics Data System (ADS)

    1992-04-01

    In fiscal year (FY) 1991, the Accelerator Technology (AT) division continued fulfilling its mission to pursue accelerator science and technology and to develop new accelerator concepts for application to research, defense, energy, industry, and other areas of national interest. This report discusses the following programs: The Ground Test Accelerator Program; APLE Free-Electron Laser Program; Accelerator Transmutation of Waste; JAERI, OMEGA Project, and Intense Neutron Source for Materials Testing; Advanced Free-Electron Laser Initiative; Superconducting Super Collider; The High-Power Microwave Program; (Phi) Factory Collaboration; Neutral Particle Beam Power System Highlights; Accelerator Physics and Special Projects; Magnetic Optics and Beam Diagnostics; Accelerator Design and Engineering; Radio-Frequency Technology; Free-Electron Laser Technology; Accelerator Controls and Automation; Very High-Power Microwave Sources and Effects; and GTA Installation, Commissioning, and Operations.

  9. In vitro atherosclerotic plaque and calcium quantitation by intravascular ultrasound and electron-beam computed tomography.

    PubMed

    Gutfinger, D E; Leung, C Y; Hiro, T; Maheswaran, B; Nakamura, S; Detrano, R; Kang, X; Tang, W; Tobis, J M

    1996-05-01

    The purpose of this investigation was to compare the accuracy of intravascular ultrasound (IVUS) and electron-beam computed tomography (EBCT) in quantitating human atherosclerotic plaque and calcium. In experiment 1, 12 human atherosclerotic arterial segments were obtained at autopsy and imaged by using IVUS and EBCT. The plaque from each arterial segment was dissected and a volume measurement of the dissected plaque was obtained by water displacement. The plaque from each arterial segment was ashed at 700 degrees F, and the weight of the remaining ashes was used as an estimate of the calcium mass. In experiment II, 11 calcified arterial segments were obtained at autopsy and imaged by using IVUS at one site along the artery. A corresponding histologic cross section stained with Masson's trichrome was prepared. In experiment I, the mean plaque volume measured by water displacement was 165.3 +/- 118.4 microliters. The mean plaque volume calculated by IVUS was 166.1 +/- 114.4 microliters and correlated closely with that by water displacement (r = 0.98, p < 0.0001). The mean calcium mass measured by ashing was 19.4 +/- 15.8 mg. The mean calculated calcium mass by EBCT was 19.9 mg and correlated closely with that by ashing (r=0.98, p<0.001). The mean calculated calcium volume by IVUS was 18.6 +/- 11.2 microliters and correlated linearly with the calcium mass by ashing (r = 0.87, p < 0.0003). In experiment II, the mean cross-sectional area of the calcified matrix was 1.71 +/- 0.66 mm2 by histologic examination compared with 1.44 +/- 0.66 mm2 by IVUS. There was a good correlation between the calcified cross-sectional area by histologic examination and IVUS (r = 0.76, p < 0.007); however, IVUS may underestimate the amount of calcium present depending on the intralesional calcium morphologic characteristics. In conclusion, IVUS accurately quantitates atherosclerotic plaque volume as well as the cross-sectional area and volume of intralesional calcium, especially if the

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