Application of Over-Sample Policy and Rotated Angle Invariability of Radial Sampling Points in the Isaf Reconstruction Algorithm

2011 ◽  
Vol 216 ◽  
pp. 485-489
Author(s):  
Gong Ming Wang ◽  
Fa Zhang ◽  
Qi Chu ◽  
Zhi Yong Liu
Keyword(s):  
High Resolution ◽  
Reconstruction Algorithm ◽  
Icosahedral Symmetry ◽  
Running Speed ◽  
Radial Sampling ◽  
3D Space ◽  
B Virus ◽  
Sampling Points ◽  
Order Of Magnitude ◽  
Symmetry Adapted Functions

ISAF (icosahedral symmetry-adapted functions) algorithm is the new high-resolution algorithm of icosahedral macromolecules. But its running speed is very slow because of the time-consuming operations of mapping sampling points into 3D space. In this paper, a new sampling method is proposed to improve the running speed of this stage. First of all, the angle corresponding to one pixel arc in the maximum Fourier ring is taken as the sampling angle and the same angle sampling is applied in every rings. After that, the sampling points in radius one ring are mapped into 3D space. Finally, the 3D spatial positions of radial sampling points in other rings can be deduced quickly according to the rotate angle invariability of radial sampling points. The HBV (Hepatitis B Virus) Cryo-electron microscopy images are used for validating this strategy. At the high resolution of 6.64 angstrom, the local speedup in the stage of mapping sampling points reaches to 50, and the overall speedup can be improved in an order of magnitude. The overall speedup increases with the increasement number of EM images and the improvement of target resolution.

scholarly journals High-resolution dynamic oxygen-17 MR imaging of mouse brain with golden-ratio-based radial sampling and k-space-weighted image reconstruction

2017 ◽  
Vol 79 (1) ◽  
pp. 256-263 ◽  
Author(s):  
Yuchi Liu ◽  
Yifan Zhang ◽  
Chunying Wu ◽  
Junqing Zhu ◽  
Charlie Wang ◽  
...  
Keyword(s):  
High Resolution ◽  
Image Reconstruction ◽  
Mr Imaging ◽  
Mouse Brain ◽  
Golden Ratio ◽  
Weighted Image ◽  
Radial Sampling

scholarly journals Mexico City aerosol analysis during MILAGRO using high resolution aerosol mass spectrometry at the urban supersite (T0) – Part 1: Fine particle composition and organic source apportionment

2009 ◽  
Vol 9 (2) ◽  
pp. 8377-8427 ◽  
Author(s):  
A. C. Aiken ◽  
D. Salcedo ◽  
M. J. Cubison ◽  
J. A. Huffman ◽  
P. F. DeCarlo ◽  
...  
Keyword(s):  
High Resolution ◽  
Mexico City ◽  
Biomass Burning ◽  
Emissions Inventory ◽  
Secondary Sources ◽  
Diurnal Cycles ◽  
Aerosol Mass ◽  
Aerosol Mass Spectrometry ◽  
Order Of Magnitude ◽  
Primary Emissions

Abstract. Submicron aerosol was analyzed during the MILAGRO field campaign in March 2006 at the T0 urban supersite in Mexico City with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and complementary instrumentation. Mass concentrations, diurnal cycles, and size distributions of inorganic and organic species are similar to results from the CENICA supersite in April 2003 with organic aerosol (OA) comprising about half of the fine PM mass. Positive Matrix Factorization (PMF) analysis of the high resolution OA spectra identified three major components: chemically-reduced urban primary emissions (hydrocarbon-like OA, HOA), oxygenated OA (OOA, mostly secondary OA or SOA), and biomass burning OA (BBOA) that correlates with levoglucosan and acetonitrile. BBOA includes several very large plumes from regional fires and likely also some refuse burning. A fourth OA component is a small local nitrogen-containing reduced OA component (LOA) which accounts for 9% of the OA mass but one third of the organic nitrogen, likely as amines. OOA accounts for almost half of the OA on average, consistent with previous observations. OA apportionment results from PMF-AMS are compared to the PM2.5 chemical mass balance of organic molecular markers (CMB-OMM, from GC/MS analysis of filters). Results from both methods are overall consistent. Both assign the major components of OA to primary urban, biomass burning/woodsmoke, and secondary sources at similar magnitudes. The 2006 Mexico City emissions inventory underestimates the urban primary PM2.5 emissions by a factor of ~4, and it is ~16 times lower than afternoon concentrations when secondary species are included. Additionally, the forest fire contribution is underestimated by at least an order-of-magnitude in the inventory.

scholarly journals How Identifying Circumgalactic Gas by Line-of-sight Velocity instead of the Location in 3D Space Affects O vi Measurements

2021 ◽  
Vol 923 (2) ◽  
pp. 137
Author(s):  
Stephanie H. Ho ◽  
Crystal L. Martin ◽  
Joop Schaye
Keyword(s):  
High Resolution ◽  
Density Profile ◽  
Column Density ◽  
Line Of Sight ◽  
Lower Mass ◽  
Star Forming ◽  
3D Space ◽  
High Incidence ◽  
High Incidence Rate ◽  
Stellar Masses

Abstract The high incidence rate of the O vi λλ1032, 1038 absorption around low-redshift, ∼L * star-forming galaxies has generated interest in studies of the circumgalactic medium. We use the high-resolution EAGLE cosmological simulation to analyze the circumgalactic O vi gas around z ≈ 0.3 star-forming galaxies. Motivated by the limitation that observations do not reveal where the gas lies along the line of sight, we compare the O vi measurements produced by gas within fixed distances around galaxies and by gas selected using line-of-sight velocity cuts commonly adopted by observers. We show that gas selected by a velocity cut of ±300 km s−1 or ±500 km s−1 produces a higher O vi column density, a flatter column density profile, and a higher covering fraction compared to gas within 1, 2, or 3 times the virial radius (r vir) of galaxies. The discrepancy increases with impact parameter and worsens for lower-mass galaxies. For example, compared to the gas within 2 r vir, identifying the gas using velocity cuts of 200–500 km s−1 increases the O vi column density by 0.2 dex (0.1 dex) at 1 r vir to over 0.75 dex (0.7 dex) at ≈ 2 r vir for galaxies with stellar masses of 109–109.5 M ⊙ (1010–1010.5 M ⊙). We furthermore estimate that excluding O vi outside r vir decreases the circumgalactic oxygen mass measured by Tumlinson et al. (2011) by over 50%. Our results demonstrate that gas at large line-of-sight separations but selected by conventional velocity windows has significant effects on the O vi measurements and may not be observationally distinguishable from gas near the galaxies.

scholarly journals Estimation of hepatitis B virus cccDNA persistence in chronic infection using within-host evolutionary rates

2020 ◽  
Author(s):  
Katrina A. Lythgoe ◽  
Sheila F. Lumley ◽  
Jane A. McKeating ◽  
Philippa C. Matthews
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Chronic Infection ◽  
Standard Of Care ◽  
Evolutionary Rates ◽  
Mathematical Framework ◽  
Novel Approach ◽  
B Virus ◽  
Order Of Magnitude ◽  
Progressive Liver Disease

AbstractHepatitis B virus (HBV) infection is a major global health problem with over 240 million infected individuals at risk of developing progressive liver disease and hepatocellular carcinoma. HBV is an enveloped DNA virus that establishes its genome as an episomal, covalently closed circular DNA (cccDNA) in the nucleus of infected hepatocytes. Currently available standard-of-care treatments for chronic hepatitis B (CHB) include nucleos(t)ide analogues (NA) that suppress HBV replication but do not target the cccDNA and hence rarely cure infection. There is considerable interest in determining the lifespan of cccDNA molecules to design and evaluate new curative treatments. We took a novel approach to this problem by developing a new mathematical framework to model changes in evolutionary rates during infection which, combined with previously determined within-host evolutionary rates of HBV, we used to determine the lifespan of cccDNA. We estimate that during HBe-antigen positive (HBeAgPOS) infection the cccDNA lifespan is 61 (36-236) days, whereas during the HBeAgNEG phase of infection it is only 26 (16-81) days. We found that cccDNA replicative capacity declined by an order of magnitude between HBeAgPOS and HBeAgNEG phases of infection. Our estimated lifespan of cccDNA is too short to explain the long durations of chronic infection observed in patients on NA treatment, suggesting that either a sub-population of long-lived hepatocytes harbouring cccDNA molecules persists during therapy, or that NA therapy does not suppress all viral replication. These results provide a greater understanding of the biology of the cccDNA reservoir and can aid the development of new curative therapeutic strategies for treating CHB.

scholarly journals Avaliação de Desempenho no Georreferenciamento de Imagens do Sensor HR CCD (High Resolution Charge-Coupled Device) do Satélite CBERS-1

2005 ◽  
Vol 32 (2) ◽  
pp. 81
Author(s):  
RAFAEL PEREIRA ZANARDI ◽  
SILVIA BEATRIZ ALVES ROLIM ◽  
CLÁUDIO BIELENKI JÚNIOR ◽  
CARLOS ALUISIO MESQUITA DE ALMEIDA
Keyword(s):  
High Resolution ◽  
Geometric Transformation ◽  
Ground Control ◽  
Control Points ◽  
Differential Gps ◽  
Charge Coupled Device ◽  
Qualitative And Quantitative ◽  
Ground Control Points ◽  
Sampling Points ◽  
Nearest Neighborhood

In this work it was analyzed the validation of CBERS-1 (China and Brazillian Earth Resourses Satellite) data related to qualitative and quantitative parameters that define the precision of its georeferencing. A topographical survey was carried out for the acquisition of ground control points spatially well distributed in the study area, employing differential GPS, aiming at the georeferencing of the image. Tests with different numbers of sampling points and several methods of Geometric Transformation and Resampling were made during the georeferencing. These results were statistically analyzed to determine the best method to georeference CBERS-1 images. It was verified that the first-degree polinomial transformation with nearest neighborhood resampling presented the best result, showing a precision of 18,52m.

scholarly journals High‐resolution in vivo MR‐STAT using a matrix‐free and parallelized reconstruction algorithm

2020 ◽  
Vol 33 (4) ◽  
Author(s):  
Oscar Heide ◽  
Alessandro Sbrizzi ◽  
Peter R. Luijten ◽  
Cornelis A.T. Berg
Keyword(s):  
High Resolution ◽  
Reconstruction Algorithm ◽  
Matrix Free

scholarly journals Aspiration-assisted bioprinting for precise positioning of biologics

2020 ◽  
Vol 6 (10) ◽  
pp. eaaw5111 ◽  
Author(s):  
Bugra Ayan ◽  
Dong Nyoung Heo ◽  
Zhifeng Zhang ◽  
Madhuri Dey ◽  
Adomas Povilianskas ◽  
...  
Keyword(s):  
Self Assembly ◽  
Physical Mechanism ◽  
Single Cells ◽  
Three Dimensional ◽  
3D Bioprinting ◽  
Precise Control ◽  
3D Space ◽  
Magnitude Range ◽  
Wide Range ◽  
Order Of Magnitude

Three-dimensional (3D) bioprinting is an appealing approach for building tissues; however, bioprinting of mini-tissue blocks (i.e., spheroids) with precise control on their positioning in 3D space has been a major obstacle. Here, we unveil “aspiration-assisted bioprinting (AAB),” which enables picking and bioprinting biologics in 3D through harnessing the power of aspiration forces, and when coupled with microvalve bioprinting, it facilitated different biofabrication schemes including scaffold-based or scaffold-free bioprinting at an unprecedented placement precision, ~11% with respect to the spheroid size. We studied the underlying physical mechanism of AAB to understand interactions between aspirated viscoelastic spheroids and physical governing forces during aspiration and bioprinting. We bioprinted a wide range of biologics with dimensions in an order-of-magnitude range including tissue spheroids (80 to 600 μm), tissue strands (~800 μm), or single cells (electrocytes, ~400 μm), and as applications, we illustrated the patterning of angiogenic sprouting spheroids and self-assembly of osteogenic spheroids.

Crystallization of hepatitis B virus core protein shells: determination of cryoprotectant conditions and preliminary X-ray characterization

1999 ◽  
Vol 55 (2) ◽  
pp. 557-560 ◽  
Author(s):  
S. A. Wynne ◽  
A. G. W. Leslie ◽  
P. J. G. Butler ◽  
R. A. Crowther
Keyword(s):  
Hepatitis B Virus ◽  
Nucleic Acid ◽  
Hepatitis B ◽  
Inner Core ◽  
Core Protein ◽  
Sub Saharan Africa ◽  
Icosahedral Symmetry ◽  
Nucleic Acid Binding ◽  
Cell Parameters ◽  
B Virus

Hepatitis B virus causes liver cirrhosis and hepatocellular cancer and is a major cause of death, particularly in Asia and sub-Saharan Africa. The virus consists of an inner core or nucleocapsid, which encloses the viral nucleic acid, with an outer lipid envelope containing surface-antigen proteins. The core protein, when expressed in E. coli, assembles into spherical shells containing 180 or 240 subunits, arranged with T = 3 or T = 4 icosahedral symmetry. The C-terminal region of the protein is involved in nucleic acid binding, and deletion of this region does not prevent capsid formation. C-terminally deleted hepatitis B core shells containing 240 subunits have been crystallized and data has been collected to 3.6 Å resolution from frozen crystals, using butanediol as a cryoprotectant. The crystals have C2 symmetry, with unit-cell parameters a = 538.0, b = 353.0, c = 369.6 Å, β = 132.3°.

scholarly journals Estimation of the advection effects induced by surface heterogeneities in the surface energy budget

2016 ◽  
Author(s):  
J. Cuxart ◽  
B. Wrenger ◽  
D. Martínez-Villagrasa ◽  
J. Reuder ◽  
M.O. Jonassen ◽  
...  
Keyword(s):  
High Resolution ◽  
Surface Energy ◽  
Energy Budget ◽  
Surface Energy Budget ◽  
Temperature Fields ◽  
Direct Measurements ◽  
Advection Term ◽  
Thermal Cameras ◽  
Remotely Piloted Aircraft ◽  
Order Of Magnitude

Abstract. The effect of terrain heterogeneities in one-point measurements is a continuous subject of discussion. Here we focus on the order of magnitude of the advection term in the equation of the temperature as generated by documented terrain heterogeneities and we estimate its importance as a term in the surface energy budget (SEB). The heterogeneities are estimated from satellite and model fields for scales near 1 kilometer or broader, while the smaller scales are estimated through direct measurements with remotely-piloted aircraft, thermal cameras and also by high-resolution modeling. The variability of the surface temperature fields is not found to decrease clearly with increasing resolution, and consequently the advection term becomes more important as the scales become finer. The advection term provides non-significant values to the SEB at scales larger than few kilometers. On the contrary, surface heterogeneities at the meter scale yield large values of the advection, which are probably only significant in the first centimeters above the ground. The motions that seem to contribute significantly to the advection term in the SEB equation in our case are roughly those around the hectometer scales.

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