Compatibility of X-ray computed tomography with plant gene expression, rhizosphere bacterial communities and enzyme activities

2020 ◽  
Vol 71 (18) ◽  
pp. 5603-5614 ◽  
Author(s):  
Minh Ganther ◽  
Bunlong Yim ◽  
Zeeshan Ibrahim ◽  
Manuela Desiree Bienert ◽  
Eva Lippold ◽  
...  
Keyword(s):  
Gene Expression ◽  
Computed Tomography ◽  
Enzyme Activities ◽  
Growth Parameters ◽  
Expression Patterns ◽  
X Rays ◽  
X Ray ◽  
Antioxidative Enzyme Activities ◽  
X Ray Computed ◽  
Low X

Abstract Non-invasive X-ray computed tomography (XRCT) is increasingly used in rhizosphere research to visualize development of soil–root interfaces in situ. However, exposing living systems to X-rays can potentially impact their processes and metabolites. In order to evaluate these effects, we assessed the responses of rhizosphere processes 1 and 24 h after a low X-ray exposure (0.81 Gy). Changes in root gene expression patterns occurred 1 h after exposure with down-regulation of cell wall-, lipid metabolism-, and cell stress-related genes, but no differences remained after 24 h. At either time point, XRCT did not affect either root antioxidative enzyme activities or the composition of the rhizosphere bacterial microbiome and microbial growth parameters. The potential activities of leucine aminopeptidase and phosphomonoesterase were lower at 1 h, but did not differ from the control 24 h after exposure. A time delay of 24 h after a low X-ray exposure (0.81 Gy) was sufficient to reverse any effects on the observed rhizosphere systems. Our data suggest that before implementing novel experimental designs involving XRCT, a study on its impact on the investigated processes should be conducted.

Visualizing Fluid Flows With X-Rays

2007 ◽  
Author(s):  
Theodore J. Heindel ◽  
Terrence C. Jensen ◽  
Joseph N. Gray
Keyword(s):  
Computed Tomography ◽  
Flow Visualization ◽  
Three Dimensional ◽  
Fluid Flows ◽  
X Rays ◽  
Radiographic Images ◽  
Optical Access ◽  
X Ray ◽  
X Ray Computed ◽  
Density Map

There are several methods available to visualize fluid flows when one has optical access. However, when optical access is limited to near the boundaries or not available at all, alternative visualization methods are required. This paper will describe flow visualization using an X-ray system that is capable of digital X-ray radiography, digital X-ray stereography, and digital X-ray computed tomography (CT). The unique X-ray flow visualization facility will be briefly described, and then flow visualization of various systems will be shown. Radiographs provide a two-dimensional density map of a three dimensional process or object. Radiographic images of various multiphase flows will be presented. When two X-ray sources and detectors simultaneously acquire images of the same process or object from different orientations, stereographic imaging can be completed; this type of imaging will be demonstrated by trickling water through packed columns and by absorbing water in a porous medium. Finally, local time-averaged phase distributions can be determined from X-ray computed tomography (CT) imaging, and this will be shown by comparing CT images from two different gas-liquid sparged columns.

scholarly journals Optimization of the energy for Breast monochromatic absorption X-ray Computed Tomography

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Pasquale Delogu ◽  
Vittorio Di Trapani ◽  
Luca Brombal ◽  
Giovanni Mettivier ◽  
Angelo Taibi ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Imaging Techniques ◽  
Fixed Dose ◽  
X Rays ◽  
Reconstruction Algorithms ◽  
Contrast Resolution ◽  
X Ray ◽  
X Ray Imaging ◽  
X Ray Computed ◽  
Dose Levels

Abstract The limits of mammography have led to an increasing interest on possible alternatives such as the breast Computed Tomography (bCT). The common goal of all X-ray imaging techniques is to achieve the optimal contrast resolution, measured through the Contrast to Noise Ratio (CNR), while minimizing the radiological risks, quantified by the dose. Both dose and CNR depend on the energy and the intensity of the X-rays employed for the specific imaging technique. Some attempts to determine an optimal energy for bCT have suggested the range 22 keV–34 keV, some others instead suggested the range 50 keV–60 keV depending on the parameters considered in the study. Recent experimental works, based on the use of monochromatic radiation and breast specimens, show that energies around 32 keV give better image quality respect to setups based on higher energies. In this paper we report a systematic study aiming at defining the range of energies that maximizes the CNR at fixed dose in bCT. The study evaluates several compositions and diameters of the breast and includes various reconstruction algorithms as well as different dose levels. The results show that a good compromise between CNR and dose is obtained using energies around 28 keV.

scholarly journals K-edge Subtraction Computed Tomography with a Compact Synchrotron X-ray Source

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Stephanie Kulpe ◽  
Martin Dierolf ◽  
Benedikt Günther ◽  
Madleen Busse ◽  
Klaus Achterhold ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Contrast Agent ◽  
Imaging Techniques ◽  
X Rays ◽  
Synchrotron Source ◽  
X Ray ◽  
Inverse Compton Scattering ◽  
Inverse Compton ◽  
X Ray Computed ◽  
Compact Light Source

Abstract In clinical diagnosis, X-ray computed tomography (CT) is one of the most important imaging techniques. Yet, this method lacks the ability to differentiate similarly absorbing substances like commonly used iodine contrast agent and calcium which is typically seen in calcifications, kidney stones and bones. K-edge subtraction (KES) imaging can help distinguish these materials by subtracting two CT scans recorded at different X-ray energies. So far, this method mostly relies on monochromatic X-rays produced at large synchrotron facilities. Here, we present the first proof-of-principle experiment of a filter-based KES CT method performed at a compact synchrotron X-ray source based on inverse-Compton scattering, the Munich Compact Light Source (MuCLS). It is shown that iodine contrast agent and calcium can be clearly separated to provide CT volumes only showing one of the two materials. These results demonstrate that KES CT at a compact synchrotron source can become an important tool in pre-clinical research.

scholarly journals OBSERVATIONS ON THE PERFORMANCE OF X-RAY COMPUTED TOMOGRAPHY FOR DIMENSIONAL METROLOGY

2016 ◽  
Vol XLI-B5 ◽  
pp. 25-31
Author(s):  
H. C. Corcoran ◽  
S. B. Brown ◽  
S. Robson ◽  
R. D. Speller ◽  
M. B. McCarthy
Keyword(s):  
Computed Tomography ◽  
Reverse Engineering ◽  
X Rays ◽  
Dimensional Metrology ◽  
Beam Hardening ◽  
X Ray ◽  
Accuracy And Precision ◽  
Dimensional Measurements ◽  
X Ray Computed

X-ray computed tomography (XCT) is a rising technology within many industries and sectors with a demand for dimensional metrology, defect, void analysis and reverse engineering. There are many variables that can affect the dimensional metrology of objects imaged using XCT, this paper focusses on the effects of beam hardening due to the orientation of the workpiece, in this case a holeplate, and the volume of material the X-rays travel through. Measurements discussed include unidirectional and bidirectional dimensions, radii of cylinders, fit point deviations of the fitted shapes and cylindricity. Results indicate that accuracy and precision of these dimensional measurements are affected in varying amounts, both by the amount of material the X-rays have travelled through and the orientation of the object.

scholarly journals Finding fossils in Malapa breccia – medical CT scanning or micro-CT scanning?

2017 ◽  
Vol 113 (11/12) ◽  
Author(s):  
Jacqueline S. Smilg
Keyword(s):  
Computed Tomography ◽  
Lower Energy ◽  
Ct Scanning ◽  
Cost Effective ◽  
High Energy ◽  
X Rays ◽  
Micro Ct ◽  
X Ray ◽  
Mechanical Preparation ◽  
X Ray Computed

Computed tomography (CT) imaging of fossils has revolutionised the field of palaeontology, allowing researchers to gain a better understanding of fossil anatomy, preservation and conservation. Micro focus X-ray computed tomography (μXCT) has been far more extensively used for these purposes than medical CT (XCT) – mostly because of the exquisite detail that the μXCT scanning modality, using slices of micron thicknesses, can produce. High energy X-rays can potentially penetrate breccia more effectively than lower energy beams. This study demonstrates that lower energy beams produce superior images for prioritising breccia for preparation. Additionally, XCT scanners are numerous, accessible, fast and relatively cost-effective when compared to μXCT scanners – the latter are not freely available, scanning times are much longer and there are significant limitations on the size and weight of scannable objects. Breccia blocks from Malapa were scanned at high and lower energy and images were analysed for image quality, artifact and certainty of diagnosis. Results show that lower energy images are deemed superior to higher energy images for this particular application. This finding, taken together with the limitations associated with the use of μXCT for the imaging of the large breccia from Malapa, shows that XCT is the better modality for this specific application. The ability to choose fossil-bearing breccia, ahead of manual mechanical preparation by laboratory technicians, would allow for the optimal use of limited resources, manual preparatory skills as well as the curtailment of costs.

Micron X-ray computed tomography based on micro-particle-induced X-ray emission

2015 ◽  
Vol 25 (03n04) ◽  
pp. 187-215
Author(s):  
Keizo Ishii
Keyword(s):  
Computed Tomography ◽  
Particle Beam ◽  
Photoelectric Effect ◽  
X Rays ◽  
Mandibular Glands ◽  
Charged Particle Beam ◽  
Atomic Collisions ◽  
Clay Particles ◽  
X Ray ◽  
X Ray Computed

Particle-induced X-ray emission (PIXE) is a phenomenon of atomic inner shell ionization and characteristic X-ray emission due to ion-atomic collisions. The intensity of continuous X-rays in the PIXE energy spectrum is much lower than that of characteristic X-rays. Therefore, PIXE can be used as a semi-monochromatic X-ray source. Furthermore, PIXE produced by a heavily charged particle beam with a diameter of several micrometers (micro-PIXE) can be used as a monochromatic X-ray point source for Xray computed tomography (CT) to investigate internal structures of objects <1 mm. We developed micron X-ray CT based on micro-PIXE with a spatial resolution of about 4 μm. Because the photoelectric effect cross-section is proportional to the fifth power of the atomic number, the distributions of small amounts of heavy elements can be investigated using this CT technique, and the element can be identified using its absorption edge. We applied this CT to observe the internal structure of hair, a head of an ant, and Drosophila. We were able to identify the medulla configuration and cortex of the hair, and the mandibular glands, pharynx, and brain in the ant head. We confirmed a high Mn concentration in the mandibular glands. We used a contrast agent to visualize the internal organs of Drosophila. Furthermore, we applied this CT to research clay particles contaminated by the Fukushima Dai-ichi nuclear accident and confirmed that cesium atoms were distributed on the surfaces of clay particles.

scholarly journals Microbial Community Characteristics Largely Unaffected by X-Ray Computed Tomography of Sediment Cores

2021 ◽  
Vol 12 ◽  
Author(s):  
Erica Ewton ◽  
Scott Klasek ◽  
Erin Peck ◽  
Jason Wiest ◽  
Frederick Colwell
Keyword(s):  
Computed Tomography ◽  
Community Structure ◽  
Microbial Community ◽  
Microbial Communities ◽  
Sediment Cores ◽  
Microbial Community Composition ◽  
Ct Scanning ◽  
X Rays ◽  
X Ray ◽  
X Ray Computed

X-ray computed tomography (CT) scanning is used to study the physical characteristics of soil and sediment cores, allowing scientists to analyze stratigraphy without destroying core integrity. Microbiologists often work with geologists to understand the microbial properties in such cores; however, we do not know whether CT scanning alters microbial DNA such that DNA sequencing, a common method of community characterization, changes as a result of X-ray exposure. Our objective was to determine whether CT scanning affects the estimates of the composition of microbial communities that exist in cores. Sediment cores were extracted from a salt marsh and then submitted for CT scanning. We observed a minimal effect of CT scanning on microbial community composition in the sediment cores either when the cores were examined shortly after recovery from the field or after the cores had been stored for several weeks. In contrast, properties such as sediment layer and marsh location did affect microbial community structure. While we observed that CT scanning did not alter microbial community composition as a whole, we identified a few amplicon sequence variants (13 out of 7,037) that showed differential abundance patterns between scanned and unscanned samples among paired sample sets. Our overall conclusion is that the CT-scanning conditions typically used to obtain images for geological core characterization do not significantly alter microbial community structure. We stress that minimizing core exposure to X-rays is important if cores are to be studied for biological properties. Future investigations might consider variables, such as the length and energy of radiation exposure, the volume of the core, or the degree, to which microbial communities are stressed as important factors in assessing the impact of X-rays on microbes in geological cores.

Associations between beef density by X-ray computed tomography, intramuscular fat and fatty acid composition: preliminary results

2009 ◽  
Vol 2009 ◽  
pp. 117-117
Author(s):  
E A Navajas ◽  
R I Richardson ◽  
C A Glasbey ◽  
N Prieto ◽  
D W Ross ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Image Analysis ◽  
Fatty Acid ◽  
Intramuscular Fat ◽  
Carcass Composition ◽  
Eating Quality ◽  
X Rays ◽  
Muscle Density ◽  
X Ray ◽  
X Ray Computed

X-ray computed tomography (CT) scanning makes use of the different rates at which the tissues attenuate X-rays depending on their densities. CT muscle density (MD) is the average pixel value for this tissue in the CT images and is related to real density of the tissue, which depends on its chemical composition. One of the components determining muscle density is intramuscular fat (IMF). Studies in sheep have shown that MD, measured in vivo, was phenotypically and genetically correlated to IMF and to fatty acid (FA) composition in Scottish Blackface lambs (Karamichou et al. 2006). Intramuscular fat and FA are important traits to measure due to their association with the nutritional value and eating quality of meat. A novel automatic image analysis for spiral CT scans (SCTS) of beef primal cuts allows very accurate estimations of primal cut and carcass composition with R2 of 0.90 to 0.99 (Navajas et al., 2008). The aim of this study was to investigate the associations of MD of beef primal cuts with IMF and FA profile in Aberdeen Angus (AA) and Limousin (LIM) cattle, based on the CT thresholds estimated as part of the development of the image analysis described by Navajas et al. (2008).

SULFUR DISPERSION QUANTITATIVE ANALYSIS IN ELASTOMERIC TIRE FORMULATIONS BY USING HIGH RESOLUTION X-RAY COMPUTED TOMOGRAPHY

2021 ◽  
Author(s):  
Dayakar Penumadu ◽  
Jun-Cheng Chin ◽  
Stephen Young ◽  
Frederick Ignatz-Hoover ◽  
Tom Floyd ◽  
...  
Keyword(s):  
Computed Tomography ◽  
High Resolution ◽  
Mechanical Performance ◽  
Domain Size ◽  
Failure Criteria ◽  
Rubber Matrix ◽  
Mixing Efficiency ◽  
X Rays ◽  
X Ray ◽  
X Ray Computed

ABSTRACT Good dispersion of compounded ingredients in a rubber formulation is important for mechanical performance. After mixing, certain materials can remain undispersed within the rubber matrix, which could lead to critical flaws, influencing performance according to the Griffith failure criteria. High resolution X-ray computed tomography (XCT) offers a unique opportunity to measure phase domain size and distributions. Fillers such as carbon black or silica can be differentiated from sulfur or zinc oxide, providing an opportunity to determine dispersion characteristics of the various phases. The XCT technique has become an important characterization tool for three-dimensional and higher dimension material science due to the availability of polychromatic micro-focus x-ray sources and efficient high spatial resolution detectors with superior scintillators. High resolution XCT provides very rich data quantifying mixing efficiency of particulates in a matrix, such as insoluble sulfur or silica particles in rubber. Imaging with X-rays provides attenuation, phase, or scattering contrast and will prove to be a critical method for evaluating the field of rubber crosslinking, considering realistic environments in situ. This paper highlights methodology development and validation and provides insight on the dispersion of polymeric (insoluble) sulfur in rubber formulations. Dispersion assessment is compared using three techniques: high resolution XCT, population survival analysis in tensile testing, and optical microscopy.

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